are readily available in the marketplace. OSHA did not receive any
comments on the proposed provision, and adopts it as proposed.
    Final paragraphs (e)(1)(iii) and (iv) establish strength and
stability requirements for mobile ladder stands and platforms to ensure
units are safe for workers to use. Final paragraph (e)(1)(iii), which
is almost identical to proposed paragraph (e)(1)(vi), requires that
employers ensure mobile ladder stands and platforms are capable of
supporting at least four times their maximum intended load. The
existing OSHA rule and ANSI standard also require that mobile ladder
stands be capable of supporting at least four times the ``design
working load'' or ``rated load,'' respectively (Sec.
1910.29(a)(2)(ii)(b); A14.7-2011, Section 4.2.1). Both standards have
been in place for many years, so OSHA believes that virtually all
mobile ladder stands and platforms manufactured and currently in use
already comply with the final rule.
    Final paragraph (e)(1)(iv), which also is almost identical to
proposed paragraph (e)(1)(iii), requires that employers ensure wheels
and casters of mobile ladder stands and platforms under load are
capable of supporting: (1) their proportional share of four times the
maximum intended load, plus (2) their proportional share of the unit's
weight. OSHA believes this requirement is necessary to ensure that
mobile ladder stands and platforms are safe for workers to use. Unless
the wheels and casters can support both the proportional weight of the
mobile ladder stand or platform and the weight of the maximum intended
load placed on that unit, failure of the wheel(s) or caster(s) may
occur. If that happens, the stand or platform could become unstable and
the worker could fall off the unit and be injured or killed.
    Final paragraph (e)(1)(iv) provides greater protection than the
existing OSHA rule in Sec.  1910.29(a)(4). The existing rule does not
require that wheels or casters be capable of supporting the weight of
the mobile ladder stand or mobile ladder stand platform, as well as the
weight of the load (e.g., worker, tools, equipment, and materials)
placed on it (Sec.  1910.29(a)(4)(i)). However, OSHA notes that the
final rule is almost identical to the ANSI standard (A14.7-2011,
Sections 4.3.7 and 4.4.8). As discussed above, the ANSI standard has
been in place for many years, so OSHA believes that virtually all
mobile ladder stand and platform wheels and casters manufactured and
currently in use already comply with the final rule.
    In final paragraphs (e)(1)(iii) and (iv), OSHA replaced the term
``design working load'' in the existing OSHA rule with ``maximum
intended load'' (i.e., the total load of all employees, equipment,
tools, materials, and other loads the employer reasonably anticipates
to be applied to the mobile ladder stand or platform). While the
definition of ``maximum intended load'' in this final rule (see Sec.
1910.21(b)) is similar to the definition of ``design working load'' in
the existing rule (see Sec.  1910.21(g)(5)), using the term ``maximum
intended load'' in final paragraphs (e)(1)(iii) and (iv) makes these
paragraphs consistent with other provisions in the final rule that use
the term.
    Finally, consistent with OSHA's goal to make the final rule
performance based, final paragraphs (e)(1)(iii) and (iv) do not
incorporate the testing requirements in either the existing OSHA rule
(Sec.  1910.29(f)(5)) or A14.7-2011 (Section 5). OSHA did not receive
any comments on either of the proposed requirements, and adopts final
paragraphs (e)(1)(iii) and (iv) as discussed above.
    Final paragraph (e)(1)(v) establishes general requirements for
handrails on mobile ladder stand and platform steps (except for
handrails on top steps when paragraph (e)(2)(ii) applies). Final
paragraph (e)(1)(v) requires that employers ensure mobile ladder stands
and platforms have handrails when the height of the top step or
platform is 4 feet or higher above lower levels. Where handrails are
required, employers must ensure that the handrails have a vertical
height of at least 29.5 inches but not more than 37 inches, as measured
from the front edge of the step, unless specified elsewhere in the
section.
    The purpose of the final paragraph (e)(1)(v) is to protect workers
from falling when they are climbing or standing on mobile ladder stands
and platforms. OSHA believes handrails are necessary to assist workers
as they are

climbing mobile ladder stands and platforms, and also provide a
handhold they can grab to steady themselves if they slip or start to
fall off the unit. In addition, handrails provide a necessary barrier
to prevent workers from falling off the side of steps and off the top
step or platform. To ensure that the barrier provides adequate
protection, OSHA notes that stands and platforms must have handrails on
both sides of the steps, including the top step and platform. On mobile
ladder stands, the handrail also must extend across the open back of
the top step.
    The existing OSHA rule requires that mobile ladder stand steps have
handrails (a minimum of 29 inches high, measured vertically from the
center of the step) if the height of the top step was more than 5 feet
or 5 steps (Sec.  1910.29(f)(4)). However, the existing rule does not
specify the maximum height allowed for the handrails. In addition, the
existing rule does not contain a specific provision covering handrails
on mobile ladder stand platforms. The proposed rule, on the other hand,
included specific and separate handrails provisions for mobile ladder
stands and mobile ladder stand platforms (proposed paragraphs
(e)(2)(ii) and (e)(3)(ii)). In the final rule, OSHA consolidated those
proposed provisions into the general requirement in paragraph (e)(1)(v)
to reduce repetition and simplify the final rule.
    The final rule provides greater protection than the existing OSHA
rule. The final rule requires that mobile ladder stands and platforms
have handrails where the top step height is at least 4 feet compared to
more than 5 feet or 5 steps in the existing rule. OSHA notes that the
ANSI standard (A14.7-2011, Sections 4.3.5 and 4.4.5) also requires that
handrails provide the same level of protection as the final rule.
    Final paragraph (e)(1)(v), like the proposal (a note to proposed
paragraphs (e)(2)(ii) and (e)(3)(ii)), also allows alternatives to the
handrails requirement for ``special-use applications.'' In such
situations, the final rule permits employers to use removable gates or
non-rigid members (such as chains) instead of handrails on the top step
of mobile ladder stands and platforms. The alternative means of
compliance allows employers to remove the gates or chains when a work
task involves special-use application; however, employers must replace
the gates or chains (i.e., comply with the handrail requirement) when
they complete the special-use task. In a special use application, it is
important that the mobile ladder stand or platform is placed to
minimize the risk of falls. For example, when a gate needs to be
removed to place or remove objects from a shelf, the employer needs to
ensure that the unit is placed so there is no gap between the unit and
shelf that could result in a worker falling while performing the task.
OSHA believes this alternative method provides flexibility for
employers while reducing the exposure of workers to fall hazards under
these conditions. For the purposes of this provision, a special-use
application may include a situation in which permanent handrails block
or impede the movement of boxes, products, or materials from the ladder
stand or platform to shelves or other storage areas. The ANSI standard
also includes this alternative method (A14.7-2011, Sections 4.3.5,
4.3.6, 4.4.5, and 4.4.6). OSHA did not receive any comments on the
proposed provisions, and adopts them as consolidated and revised.
    Final paragraph (e)(1)(vi), like the existing OSHA and proposed
rules (Sec.  1910.29(a)(3)(i) and (f)(2); proposed paragraph
(e)(1)(v)), requires that employers ensure the maximum work-surface
height of mobile ladder stands and platforms does not exceed four times
the shortest dimension of the base, without additional support. OSHA
believes this requirement is necessary to prevent units from tipping
over and injuring workers. Also consistent with the existing and
proposed rules, the final rule specifies that when mobile ladder stands
and platforms need to reach greater heights, the employer must provide
additional support such as outriggers, counterweights, or comparable
means to stabilize the base and prevent the unit from overturning. The
ANSI standard includes the same requirement (A14.7-2011, Section 5.2).
    Final paragraph (e)(1)(vi) differs from the existing OSHA rule in
one respect: it does not incorporate the testing requirement in
existing Sec.  1910.29(f)(2) for calculating the maximum base length,
opting instead to adopt a performance-based requirement. Similarly, it
does not incorporate the A14.7-2011 testing provisions. OSHA did not
receive any comments on the proposal, and adopts it with minor
editorial clarifications.
    Final paragraph (e)(1)(vii), like proposed paragraph (e)(1)(iv),
requires that employers ensure wheels and casters on mobile ladder
stands and platforms are equipped with a system that will impede
horizontal movement when a worker is on the unit. OSHA drew the final
requirement from the ANSI standard (A14.7-2011, Sections 4.3.8 and
4.4.9); the existing OSHA rule does not contain a similar provision.
OSHA believes the requirement in final paragraph (e)(1)(vii) is
necessary to prevent accidental or inadvertent movement of a mobile
ladder stand or platform. If the stand or platform suddenly moves, it
may cause the worker to fall off the unit. Sudden movement also can
cause materials, equipment, and tools to fall off a mobile ladder stand
or platform and hit employees working in the immediate area. The phrase
``rigid and swivel'' has been removed from the proposed language
because it is unnecessary. In addition, OSHA added the phrase ``when an
employee is on a stand or platform'' to the proposed text to clarify
that it is acceptable that mobile ladder stands move at other times.
OSHA did not receive any comments on the proposed rule, and adopts it
as discussed.
    Final paragraph (e)(1)(viii), like proposed paragraph (e)(1)(vii),
requires that employers ensure mobile ladder stands and platforms do
not move while workers are on them. The final rule will prevent workers
from falling from mobile ladder stands and platforms. Working on a
unit, particularly on the top step or platform, raises the unit's
center of gravity, causing the unit to become less stable. If somebody
moves the unit, intentionally or not, a worker on the unit could lose
his or her balance and experience a serious fall. The same consequences
could occur if a worker rides on a mobile ladder stand or platform when
somebody moves the unit to a new location in the workplace.
    OSHA also drew this requirement from A14.7-2011 (Section 6.4)
because the existing rule does not contain a similar requirement. OSHA
did not receive any comments on the proposed rule, and adopted it as
proposed with minor editorial changes for clarity.
    Final paragraph (e)(2) establishes design requirements for mobile
ladder stands that apply to mobile ladder stands in addition to the
general mobile ladder stand and platform requirements in final
paragraph (e)(1). As with the general requirements in final paragraph
(e)(1), OSHA carried forward most of the provisions in final paragraph
(e)(2) from its existing rule (Sec.  1910.29) or from A14.7-2011.
    Final paragraph (e)(2)(i), like proposed paragraph (e)(2)(i),
establishes requirements for mobile ladder stand steps. The employer
must ensure that these steps:
     Are uniformly spaced and arranged;
     Have a maximum rise of 10 inches; and
     Have a minimum depth of 7 inches.
    The final rule also requires that the employer ensure the slope
(angle) of the

``step stringer'' to which the steps are attached is not more than 60
degrees from horizontal. A step stringer (also called a ``stile'' or
``siderail'') is the inclined structural member that supports the steps
(treads).
    The requirements in final paragraph (e)(2)(i) are consistent with
the general requirements for ladders in final paragraph (b) of this
section. Final paragraph (b) also requires that ladder steps be
``parallel, level, and uniformly spaced'' (final paragraph (b)(1)) and
have steps spaced ``not less than 10 inches and not more than 14 inches
apart'' (final paragraph (b)(2))(see discussion of final paragraph (b)
above).
    Final paragraph (e)(2)(i) differs from the existing OSHA rule
(Sec.  1910.29(f)(3)) in two respects. The final rule does not carry
forward the existing requirements to have (1) a 9-inch minimum rise for
mobile ladder stand steps, and (2) a minimum 55-degree slope for step
stringers. OSHA believes final paragraph (e)(2)(i) simplifies the rule
and provides greater compliance flexibility. Since the final rule is
virtually identical to the ANSI standard (A14.7-2011, Section 4.3.3),
OSHA also believes the revisions to the final rule do not compromise
worker protection. OSHA did not receive any comments on the proposed
rule, and adopted it with minor editorial revisions.
    Final paragraph (e)(2)(ii), like proposed paragraph (e)(2)(iii) and
the ANSI standard (A14.7-2011, Section 4.3.6), establishes requirements
for mobile ladder stands with a top step height more than 10 feet above
lower levels. Final paragraph (e)(2)(ii) requires that employers ensure
these mobile ladder stands have handrails on three sides of the top
step. The employer must ensure that the handrail has a vertical height
of at least 36 inches. Also, top steps with a length (depth) of at
least 20 inches, front to back, must have midrails and toeboards.
    The requirements in final paragraph (e)(2)(ii) provide additional
protection from falls and falling objects that are particularly
important when employees work on taller mobile ladder stands. To
protect workers from falls, final paragraph (e)(2)(ii) ensures that
workers have a handhold to grab onto while they are climbing or located
on the top step. In addition, final paragraph (e)(2)(ii) requires top
steps that are at least 20 inches in depth to be provided with a
midrail and toeboard. This protects adjacent workers from falling
objects when the top step becomes large enough for the possibility of
materials, tools, equipment, or other objects to be placed on the top
step. OSHA drew the requirements in final paragraph (e)(2)(ii) from the
ANSI standard (A14.7-2011, Section 4.3.6). The existing OSHA rule
(Sec.  1910.29(f)(4)) does not include any of these protections.
    Although final paragraph (e)(2)(ii) is similar to proposed
paragraph (e)(2)(iii), it also differs in some respects. OSHA
reorganized the final paragraph so it is a plain-language provision.
OSHA believes that the reorganized provision in the final rule is
easier for employers to understand than the proposed provision.
    Also, final paragraph (e)(2)(ii) contains two clarifications of the
proposed provision. First, final (e)(2)(ii) clarifies the handrail,
midrail, and toeboard requirements, stating that employers must provide
these protective structures on three sides of the top step. Although
OSHA believes that most employers understand that locating handrails,
midrails, and toeboards on three sides is necessary to provide adequate
protection to their workers, the final rule expressly clarifies this
requirement.
    Second, a note to final paragraph (e)(2)(ii), like final paragraph
(e)(1)(v), incorporates an alternative method from the handrail and
midrail requirement for special-use applications. (See the explanation
of the exception for special-use applications in paragraph (e)(i)(v)
above.) OSHA did not receive any comments on the proposed provision,
and adopts it as revised.
    Final paragraph (e)(2)(iii), like proposed paragraph (e)(2)(iv),
requires that employers ensure the standing areas of mobile ladder
stands are within the base frame. OSHA believes this requirement is
necessary to ensure the stability of mobile ladder stands. Keeping the
center of gravity within the base frame increases the stability of the
mobile ladder stand. This requirement reduces the potential for the
mobile ladder stand to tip when a worker is using it.
    OSHA drew final paragraph (e)(2)(iii) from the ANSI standard
(A14.7-2011, Section 4.3.9) since the existing OSHA rule does not
include this requirement. Consistent with the goal of making the final
rule more performance based, OSHA did not adopt the stability-testing
requirements in the ANSI rule (A14.7-2011, Section 5). OSHA did not
receive any comments on the proposed provision, and adopts it as
proposed.
    Employers must comply with the design requirements for mobile
ladder stand platforms specified by final paragraph (e)(3), as well as
the general requirements for mobile ladder stands and platforms in
final paragraph (e)(1). OSHA drew most of these requirements from
A14.7-2011. In addition, OSHA expanded the existing requirements on
mobile ladder stands in Sec.  1910.29 that apply to mobile ladder stand
platforms.
    Final paragraph (e)(3)(i), like the proposed paragraph and final
paragraph (e)(2)(i), requires that employers ensure the steps of mobile
ladder stand platforms:
     Are uniformly spaced and arranged;
     Have a maximum rise of 10 inches; and
     Have a minimum depth of 7 inches.

The final rule also requires that the employer ensure the slope (angle)
of the ``step stringer'' to which the steps are attached is not more
than 60 degrees from horizontal.
    Final paragraph (e)(3)(i) differs from final paragraph (e)(2)(i) in
one respect. It includes an exception when the employer demonstrates
that the final requirement is not feasible. In that circumstance, the
employer may use mobile ladder stand platforms that have steeper slopes
or vertical rung ladders, provided the employer stabilizes the
alternative unit to prevent it from overturning. The final rule
includes this exception because OSHA recognizes that there may be
situations or locations where, for example, the slope of the step
stringer on a mobile ladder stand platform may need to be greater than
the 60-degree limit. To illustrate, there may be a workplace space
where the employer needs to use a mobile ladder stand platform, but the
unit does not fit. In that situation, OSHA believes it would be
appropriate to use an alternative unit with a steeper stringer slope or
a vertical rung ladder that takes up less space.
    The ANSI standard also includes a similar exception for mobile
ladder stand platforms (A14.7-2011, Section 4.4.3). The exception in
the ANSI standard specifically permits employers to use alternative
mobile ladder stand platforms that have steps with a slope of 60 to 70
degrees. OSHA notes that some alternative units consist of retractable
ship's stairs which, consistent with final Sec.  1910.25(e)(1), have a
slope of 60 to 70 degrees. When employers demonstrate the final rule is
not feasible, OSHA notes that employers will be in compliance with
final paragraph (e)(3)(i) if they use mobile ladder stand platforms
with a slope of up to 70 degrees, the limit permitted by A14.7-2011,
Section 4.4.3. The exception also requires that employers properly
stabilize the alternative unit to reduce the risk of workers falling
off the steeper steps. OSHA did not receive any comments on the
proposed provision, and adopts it as discussed above.
    Final paragraphs (e)(3)(ii) and (iii) establish requirements
addressing the

platform area of mobile ladder stand platforms. When the height of the
platform is 4 feet to 10 feet, final paragraph (e)(3)(ii) requires that
employers ensure the platform areas have handrails and midrails.
Employers also must ensure the handrails on the platforms in this
height range have a vertical height of at least 36 inches. As discussed
in final paragraph (e)(2)(ii), these requirements are necessary to
protect workers from falling off walking-working surfaces that are 4
feet or more above a lower level.
    Although the existing OSHA rule contains a requirement for
handrails on mobile ladder stands (Sec.  1910.29(f)(4)), it only
requires that the vertical of height of the handrails be at least 29
inches, which is not as protective as the ANSI standard. Therefore,
OSHA adopted final paragraph (e)(3)(ii) from the ANSI standard (A14.7-
2011, Section 4.4.4).
    Final paragraph (e)(3)(ii) differs from the proposed rule in that
OSHA removed the proposed requirement that mobile ladder stand
platforms have handrails on the steps if the top step height is 4 feet
to 10 feet. The final rule consolidated that requirement in final
paragraph (e)(1)(v), which preserves the step-handrail requirement for
both mobile ladder stands and platforms. (See discussion of handrails
in the summary of final paragraph (e)(1)(v) above.) OSHA did not
receive any comments on the proposed requirement, and adopts it as
revised.
    Final paragraph (e)(3)(iii), like the proposal (proposed paragraph
(e)(3)(iii)), establishes requirements for mobile ladder stand
platforms that are more than 10 feet above a lower level. For these
units, the final rule requires that employers must ensure that the
exposed sides and ends of the platforms have both guardrails and
toeboards. OSHA notes that all fall protection and falling object
protection requirements must meet the systems criteria in final Sec.
1910.29.
    OSHA believes it is essential that guardrails on platforms that are
more than 10 feet in height comply with the criteria in final Sec.
1910.29(b) to ensure that employers adequately protect workers from
falling off the platforms. OSHA also believes that toeboards must meet
the criteria in final Sec.  1910.29(k)(1) to ensure workers on the
ground are not hit by falling objects. The toeboards must, consistent
with the requirements of Sec.  1910.29:
     Have a vertical height of at least 3.5 inches;
     Not have more than a 0.25-inch clearance above the
platform surface;
     Be solid or have openings that do not exceed 1-inch at the
greatest dimension; and
     Be capable of withstanding a force of at least 50 pounds
applied at any downward or outward direction at any point along the
toeboard (see final Sec.  1910.29(k)(1)(ii)).
    Lastly, like final paragraphs (e)(1)(v) and (e)(2)(ii), final
paragraph (e)(3)(iv) includes language, proposed as a note to this
provision, that permits the use of removable gates or non-rigid members
instead of handrails and guardrails in special-use applications (see
further discussion of special-use applications in final paragraph
(e)(1)(v) above). OSHA did not receive any comments on the proposed
provisions, and adopts them as revised.
Section 1910.24--Step Bolts and Manhole Steps
    Final Sec.  1910.24, like the proposed rule, establishes new
design, strength, and use requirements for step bolts and manhole
steps. The final rule defines a step bolt as ``a bolt or rung attached
at intervals along a structural member used for foot placement and as a
handhold when climbing or standing'' (Sec.  1910.21(b)). Step bolts,
often are used on metal poles or towers, and include pole-steps,
commonly used on wooden poles such as utility poles.
    The final rule, like the proposed rule, defines manhole steps as
``steps individually attached to, or set into, the wall of a manhole
structure'' (Sec.  1910.21(b)). Manhole steps are cast, mortared, or
attached by mechanical means into the walls of the base, riser, and
conical top sections of a manhole.
    Telecommunications, gas, and electric utility industries are the
industries that most often use step bolts and manhole steps.
Manufacturing establishments also use them instead of conventional
ladders and stairs, especially in locations where it is infeasible to
use ladders and stairs.
    OSHA drew the step bolt and manhole step requirements in the final
rule from the following six sources:
     The step bolt, pole step, and manhole ladder requirements
in OSHA's Telecommunications standard (29 CFR 1910.268);
     The step bolt and manhole step provisions in OSHA's 1990
proposed Walking and Working Surfaces and Personal Protective Equipment
(Fall Protection Systems) standard (55 FR 13360), which drew its
requirements from proposed Electric Power Generation, Transmission, and
Distribution standard (29 CFR 1910.269) (54 FR 4974 (1/31/1989));
     American National Standards Institute/Telecommunications
Industry Association (ANSI/TIA) 222-G-1996, Structural Standard for
Antenna Supporting Structures and Antennas (ANSI/TIA 222-G-1996) (Ex.
33);
     American National Standards Institute/Telecommunications
Industry Association (ANSI/TIA) 222-G-2005, Structural Standard for
Antenna Supporting Structures and Antennas (ANSI/TIA 222-G-2005) (Ex.
27);
     American Society for Testing and Materials (ASTM) C 478-
13, Standard Specification for Precast Reinforced Concrete Manhole
Sections (ASTM C 478-13) (Ex. 381); and
     American Society for Testing and Materials (ASTM) A 394-
08, Standard Specification for Steel Transmission Tower Bolts, Zinc-
Coated and Bare (ASTM A 394-08).

The requirements in final Sec.  1910.24 replace the step bolt, pole
step, and manhole step provisions in the existing Telecommunications
standard (Sec.  1910.268(h)), and final Sec.  1910.23 replaces the
ladder requirements in Sec.  1910.268(h). Thus, the final rule deletes
those requirements from Sec.  1910.268(h). Therefore, the
telecommunications industry, as well as all other users of ladders,
step bolts, and manhole steps in general industry must comply with the
ladder, step bolt, and manhole step requirements in revised subpart D.
    Consistent with section 6(b)(5) of the OSH Act (29 U.S.C.
655(b)(5)), the final rule is performance based to the extent possible.
For example, final paragraph (a)(2) of this section requires that the
employer ensure that step bolts are designed, constructed, and
maintained to prevent the worker's foot from slipping off the ends,
instead of mandating specific requirements on the size and shape that
the step bolt heads must meet.
    OSHA notes that two of the step bolt provisions (final paragraphs
(a)(1) and (7)), and all but two of the manhole step requirements
(final paragraph (b)(2)), apply only to those steps installed after the
effective date of the final rule. OSHA recognizes that many step bolts
and manhole steps already in workplaces currently comply with the
requirements in final Sec.  1910.24. This high rate of compliance, OSHA
believes, is the result of the Agency issuing its Telecommunications
standard in 1975 (40 FR 13341 (3/26/1975)), and because the national
consensus standards addressing step bolts and manhole steps have been
in place for a number of years. That said, OSHA believes the most
efficient and least disruptive way

to implement the final rule is to require employers to comply with the
final rule when they install new step bolts and manhole steps.
Employers may install new step bolts and manhole steps when they
install new structures (e.g., telecommunications and utility towers),
or when they replace damaged step bolts and manhole steps (e.g.,
broken, missing) that are hazardous for workers to use. Because final
paragraphs (a)(8) and (b)(3) of this section require that employers
inspect step bolts and manhole steps, respectively, at the start of
each work shift, OSHA believes that employers will quickly and readily
identify whether hazardous conditions, including damage, are present.
If such conditions are present, final Sec.  1910.22(d)(2) and (3)
require that employers repair, correct, or replace the step bolts or
manhole steps.
    For example, if an inspection of an electric utility tower finds a
corroded step bolt that cannot support the required load (final
paragraphs (a)(6) and (7)), the final rule requires that the employer
replace it with one made of corrosion-resistant materials or with
corrosion-resistant coatings (final paragraph (a)(1)). However, if the
inspection shows existing step bolts still have useful life, i.e., they
can support the required load and meet the other requirements in final
paragraph (a), the employer can continue to use the step bolt even if
it is not made with corrosion-resistant materials or coatings. OSHA
believes that following this type of implementation strategy and
schedule, rather than requiring employers to retrofit all existing step
bolts not made with corrosion-resistant materials or coatings, will
ensure that the final rule does not impose an undue burden on
employers, while ensuring that the existing step bolts are safe for
workers to use.
Paragraph (a)--Step Bolts
    Paragraph (a) of the final rule, like the proposal, establishes
requirements addressing the design, dimensions, strength, and
installation of step bolts. OSHA received a comment recommending that
the final rule prohibit the use of step bolts unless it requires that
employers provide fall protection, such as ladder safety systems, when
workers use step bolts (Ex. 155). Dr. J. Nigel Ellis, of Ellis Fall
Safety Solutions, referenced a 1990 Duke Power study he said
demonstrated step bolts had a high breaking frequency, and therefore,
that fall protection was necessary for workers using step bolts. Dr.
Ellis also said fall protection needed to be continuous, and not
require the worker to manipulate or handle objects when climbing.
    OSHA addressed in final Sec.  1910.28 Dr. Ellis' concerns about
protecting workers using step bolts that break unexpectedly. That
section requires that employers provide fall protection for workers on
any walking-working surface with an unprotected side or edge that is
four feet or more above a lower level (Sec.  1910.28(b)). The final
rule is more protective than ANSI/TIA 222-G-2005, which requires that
antenna-supporting structures designed for climbing to heights greater
than 10 feet must have at least one climbing facility (e.g., step
bolts) and a ``safety climb device'' (Section 12.3). The ANSI/TIA 222-
G-2005 standard defines a ``safety climb device'' as ``a support system
that may be a cable or solid rail attached to the structure'' (Section
12.2), and specifies that the device meet the requirements in the A14.3
standard (Section 12.4).
    Final paragraph (a)(1), 1ike the proposed rule, requires that
employers ensure step bolts installed in an environment where corrosion
may occur are constructed of, or coated with, material that protects
against corrosion. The final rule is consistent with 1990 proposed
Sec.  1910.24(b)(6) (55 FR 13399). The ANSI/TIA 222-G-2005 standard
requires that structural steel members and components must have zinc
coating (Section 5.6.1). Although the national consensus standard
specifies that hot-dip galvanizing is the preferred method, employers
may use other equivalent methods (Section 5.6.1).
    Corrosive environments can cause damage to unprotected metals. For
example, corrosion can lead to deterioration and weakening that may
cause step bolts to break or fail to support the total required load.
OSHA believes that corrosion-resistant materials and coatings will
protect step bolts and ensure they are capable of supporting at least
four times the maximum intended load.
    Final paragraph (a)(1), like the proposed rule, applies the
requirement prospectively to step bolts installed on or after the
effective date of the final rule. As noted above, OSHA believes this is
the most efficient way to implement this provision while, at the same
time, ensuring worker protection. Mr. Robert Miller, of Ameren
Corporation, supported OSHA's decision to make the paragraph (a)(1)
prospective (Ex. 189). Accordingly, OSHA is adopting paragraph (a)(1)
as discussed.
    Final paragraph (a)(2), similar to the proposed rule, requires that
employers ensure step bolts are designed, constructed, and maintained
to prevent the worker's foot from slipping off the end of it. If a
worker's foot slips off the end of the step bolt, the worker could fall
or sustain an injury from slipping. Designing the head of the step bolt
to prevent the worker's foot from slipping off will provide the
requisite protection. Final paragraph (a)(2) also is consistent with
the ANSI/TIA 222-G-2005 standard (Section 12.5(f)), as well as 1990
proposed Sec.  1910.24(b)(5).
    The proposed rule specified that step bolts be ``designed to
prevent slipping or sliding off the end of the bolt,'' but the proposal
also required step bolts to be ``designed, constructed, and
maintained'' free of recognized hazards (proposed Sec.  1910.22(a)(3)).
Only properly designed, constructed, and maintained step bolts will be
effective in preventing the worker's foot from slipping off the end,
therefore the Agency added ``constructed and maintained'' to final
paragraph (a)(2) to emphasize that step bolts must meet these
requirements as well. OSHA did not receive any comments on the proposed
provision and has adopted paragraph (a)(2) with the revisions
discussed.
    Final paragraph (a)(3), like the proposed rule, requires that
employers ensure step bolts are uniformly spaced at a vertical distance
of not less than 12 inches and not more than 18 inches apart, measured
center to center. The final paragraph also notes that the spacing from
the entry and exit surface to the first step bolt may differ from the
spacing between other step bolts. This requirement means that the
maximum uniform spacing between alternating step bolts is 18 inches,
resulting in a maximum spacing between step bolts on the same side of
36 inches. OSHA believes that uniform spacing helps to ensure safe
climbing when using step bolts. (Figure D-6 illustrates the vertical
spacing requirements in the final rule.)
    The final rule generally is consistent with the proposed rule and
the existing Telecommunications standard (Sec.  1910.268(h)(2)), which
limit the maximum vertical spacing between step bolts (alternating) to
18 inches. OSHA adopted the Telecommunications standard in 1975 based
on recommendations of a voluntary committee of representatives from
telephone companies and communication unions (40 FR 13341 (3/26/1975)).
The 1990 proposal specified that the spacing between step bolts be
between 6 and 18 inches (Sec.  1910.24(b)(1)). The ANSI/TIA 222-G-2005
standard requires that the spacing between step bolts be between 10 to
16 inches, with a tolerance of  1 inch (Section 12.5).

    In the proposed rule, OSHA requested, but did not receive, comments
on whether the Agency should adopt the proposed requirement or the
spacing that the ANSI/TIA 222-G-2005 standard specifies. OSHA believes
that adopting the maximum 18-inch uniform vertical spacing requirement
in final paragraph (a)(3) is appropriate for two reasons. First, as
mentioned earlier, the step bolt requirement in the Telecommunications
standard has been in place for more than 35 years. During that period,
the telecommunications industry constructed many towers that have step
bolts spaced no more than 18 inches apart. OSHA has no data showing
that the maximum 18-inch vertical step bolt spacing requirement in the
Telecommunications standard poses any safety problems or resulted in
any injury in that industry. Moreover, OSHA believes that most of the
telecommunications industry already is in compliance with Sec.
1910.268, and that final paragraph (a)(3) would not impose a financial
burden on employers.
    Second, if the 1-inch tolerance allowed in the ANSI/TIA
222-G-2005 standard is taken into account, there is, at most, only a 1-
inch difference in the maximum vertical spacing in final paragraph
(a)(3) and the ANSI/TIA 222-G-2005 standard. OSHA does not consider
this difference to be significant in this provision. Therefore, OSHA is
adopting in the final provision, the step bolt spacing requirement
(between 12 and 18 inches) that is consistent with OSHA's
Telecommunications standard.
    Final paragraph (a)(3), like the proposed rule, allows the spacing
of step bolts at the entry and exit surface to the first step bolt to
differ from the uniform spacing between the other step bolts. For
example, the first step bolt on a monopole may be 10 feet above the
ground. Having a higher first step bolt on a structure is not unusual;
in many cases, this configuration limits unauthorized access to the
structure's hazardous heights, communication devices, or electrical
wiring.
    OSHA's Telecommunications standard also allows the spacing of the
initial step bolt to differ from the other steps, ``except where
working, standing, or access steps are required'' (existing Sec.
1910.268(h)(2)). The 1990 proposal did not specifically address spacing
of the initial step bolt. Section 12.5(a) of ANSI/TIA 222-G-2005
requires that ``spacing shall remain uniform over a continuous length
of climb,'' but does not address entry and exit spacing. OSHA believes
that allowing a variation in spacing from the entry surface to the
first step bolt or from the last step bolt to the exit surface will
make it easier and safer for workers to establish their foothold. Once
again, since the Telecommunication standard allows the spacing on the
first and exit step bolt to differ and OSHA is not aware of any
injuries or problems occurring as a result, the Agency is adopting
paragraph (a)(3) as proposed, with minor editorial revisions.
    Final paragraph (a)(4), like the proposed rule, requires that
employers ensure step bolts have a minimum clear width of 4.5 inches.
The final rule is the same as OSHA's Telecommunications standard (Sec.
1910.268(h)(2)); 1990 proposed Sec.  1910.24(b)(2); and the ANSI/TIA
222-G (2005) standard (Section 12.5(f)).
    OSHA believes it is necessary that workers have an adequate space
on which to step and secure their foothold while climbing or they could
slip and fall. OSHA believes the telecommunications industry supports
the 4.5-inch minimum clear-step width in the Telecommunications and
ANSI/TIA 222-G-2005 standards. In addition, since both standards have
been in place for many years, OSHA believes the industry already is in
compliance with the minimum clear width requirement.
    Mr. Larry Halprin, of Keller and Heckman, said that OSHA should
only apply the vertical spacing distance (final paragraph (a)(3)) and
minimum clear width (final paragraph (a)(4)) requirements prospectively
(Ex. OSHA-S029-2006-0662-0381). He stated that, in the OSHA notice
reopening the rulemaking docket on subpart D, the Agency said that the
1990 proposal specified prospective application of the revised
provisions, and ``would allow workplaces and equipment meeting existing
subpart D requirements to be `grandfathered in''' (68 FR 23529 (5/2/
2003)). However, neither the 2010 nor the 1990 proposed rules stated
that OSHA would apply the vertical spacing or minimum clear width
requirements prospectively. In addition, as mentioned, the
Telecommunications and ANSI/TIA 222-G-2005 standards, which have been
in place more than 35 years, include both requirements. Moreover, OSHA
received no comments from affected industries indicating that they
could not meet the existing vertical spacing and minimum clear width
requirements. Therefore, OSHA believes that most employers already are
in compliance with final paragraphs (a)(3) and (4). Accordingly, OSHA
does not believe it is necessary to limit the vertical spacing and
minimum clear width requirements to prospective application and adopts
the provisions as proposed, with minor editorial revisions.
    Final paragraph (a)(5), like the 2010 and 1990 proposed rules,
requires that employers ensure the minimum perpendicular distance
between the centerline of each step bolt to the nearest permanent
object in back of the step bolt is at least 7 inches. When employers
can demonstrate that they cannot avoid an obstruction, the final rule
permits them to reduce the minimum perpendicular clearance space to 4.5
inches.
    The required 7-inch minimum perpendicular clearance space in final
paragraph (a)(5) is consistent with the minimum perpendicular clearance
for fixed ladders in final Sec.  1910.23(d)(2), the construction
ladders standard (Sec.  1926.1053(a)(13)), and ANSI/TIA 222-G-2005
standard (Section 12.5). However, final paragraph (a)(5), like the 2010
and 1990 proposals, provides more flexibility than those standards.
When the employer demonstrates that an obstruction is not avoidable,
final paragraph (a)(5) allows employers to reduce the minimum
perpendicular clearance to 4.5 inches for any step bolt.
    OSHA believes that a 7-inch minimum perpendicular clearance for
step bolts, like fixed ladders, is necessary to ensure workers are able
to maintain a secure foothold and negotiate the step bolts while they
are climbing or working. Because the final rule gives employers the
flexibility to reduce the minimum perpendicular clearance space for any
step bolt if an obstruction cannot be avoided, the Agency believes that
employers need to be able to demonstrate that they made a case-by-case
evaluation and determination that the obstruction was not avoidable in
the specific instance. For example, where an employer uses step bolts
in an industrial setting because it is not feasible to use fixed
ladders or stairs (e.g., space limits), employers need to show they
evaluated the specific situation and considered potential options in
determining whether they could avoid or remove the obstruction. The
language in the final rule clarifies the Agency's intent about the
situations in which employers may reduce the minimum perpendicular
clearance space on a step bolt. The Agency did not receive comments on
proposed paragraph (a)(5) and adopts the requirement as discussed.
    Final paragraphs (a)(6) and (7) address strength requirements for
existing step bolts and for step bolts installed on or after the
effective date of the final rule. The final rule establishes different
strength requirements for existing and new step bolts to reduce the
need for

retrofitting step bolts that currently meet the maximum intended load
requirements in final Sec.  1910.22(b) and still have useful life.
    Final paragraph (a)(6), like the proposed rule, requires that
employers ensure each step bolt installed before the effective date of
the final rule is capable of supporting the maximum intended load. The
final rule defines maximum intended load as ``the total load (weight
and force) of all workers, equipment, vehicles, tools, materials, and
loads the employer reasonably anticipates to be applied to a walking-
working surface at any one time'' (Sec.  1910.21(b)).
    The final provision is based on the Telecommunications standard
requirement that employers shall ensure that no employee nor any
material or equipment may be supported or permitted to be supported on
any portion of a ladder unless it is first determined, by inspections
and checks conducted by a competent person that such ladder is
adequately strong, and in good condition (Sec.  1910.268(h)(1)), and is
consistent with 1990 proposed Sec.  1910.24(c)(2). The ANSI/TIA 222-G-
2005 standard establishes strength specifications:

    A load factor, [alpha]L = 1.5, shall be applied to
the nominal loads specified herein:
    The minimum nominal load on individual rungs or steps shall be
equal to a normal concentrated load of 250 lbs [1.1 kN] applied at
the worst-case location and direction.
    The minimum nominal load on ladders shall be 500 lbs [2.2 kN]
vertical and 100 lbs [445 N] horizontal applied simultaneously,
concentrated at the worst-case location between consecutive
attachment points to the structure (Section 12.4).

    The general requirements in the final rule specify that employers
ensure all walking-working surfaces are capable of supporting the total
weight and force employers reasonably anticipate placing on that
surface (Sec.  1910.22(b)). Final paragraph (a)(6) reinforces that this
requirement applies as well to existing step bolts. OSHA believes step
bolts that cannot support their maximum intended load are not safe to
use, regardless of when the employer installed them.
    The ANSI/TIA 222-G standard has been in place since 2005, and OSHA
believes most step bolts manufactured today meet the requirements of
that standard. In addition, OSHA's experience is step bolt
manufacturers generally specify maximum loads that step bolts can
withstand without failure. As such, OSHA believes that most existing
step bolts are in compliance with final paragraph (a)(6) and Sec.
1910.22(b). That said, employers must continue to inspect step bolts to
ensure that the loads placed on the step bolts covered by this
provision do not exceed the maximum intended loads and manufacturer
specifications. This is because failure or deflection of step bolts can
occur during use, particularly since the weight on step bolts is not
static and varies as a worker climbs. OSHA did not receive any comments
on proposed paragraph (a)(6), and is adopting it as discussed.
    Final paragraph (a)(7), like the proposed rule, requires that
employers ensure each step bolt installed on or after the effective
date of the final rule is capable of supporting at least four times its
maximum intended load. As discussed in the proposed rule, OSHA believes
that requiring step bolts be capable of supporting four times the
maximum intended load is necessary to provide a safety factor that is
adequate to ensure that step bolts do not fail during use. The required
safety factor (i.e., 4 times the maximum intended load) will provide an
additional level of assurance that step bolt are safe for workers to
use. OSHA believes that common engineering practice requires
manufacturers to include a safety factor in any product design to
account for any unanticipated conditions that may stress the product
beyond its designed capabilities.
    Final paragraph (a)(7) is consistent with 1990 proposed Sec.
1910.24(c)(1), which specified that ``[e]ach step bolt shall be capable
of withstanding, without failure, at least four times the intended load
calculated to be applied to the [step] bolt.'' In addition, as
mentioned above, the Telecommunications standard requires any portion
of a ladder to be ``adequately strong,'' while the ANSI/TIA 222-G-2005
standard establishes specification requirements.
    The ASTM A 394-08 standard establishes specification for step bolts
with nominal thread diameters of \1/2\, \5/8\, \3/4\, \7/8\ and 1-inch
(Ex. 383). OSHA believes that \5/8\-inch diameter steel step bolts
normally comply with the strength requirement in final paragraph
(a)(7), and are the most commonly used step bolts in general industry.
Manufacturers also produce step bolts smaller than \5/8\-inch diameter,
but OSHA notes that \1/2\-inch step bolts may not comply with final
paragraph (a)(7).
    Final paragraph (a)(7), unlike the ANSI/TIA and ASTM standards, is
a performance-based requirement. OSHA believes that giving employers
flexibility in determining the maximum load they anticipate applying to
any step bolt will ensure that the maximum intended load accurately
reflects the particular work and workplace conditions present. By
contrast, OSHA believes that the ANSI/TIA 222-G-2005 test procedures
are for manufacturers, not employers, because manufacturers are in the
best position to test whether step bolts meet the strength
requirements. Employers are free to use the specifications and test
procedures in the ANSI/TIA national consensus standard to determine
whether their step bolts meet the maximum intended load requirements in
final paragraph (a)(7).
    OSHA received two comments on the proposed requirement. As
discussed in final paragraph (a)(1), Mr. Miller, of Ameren, supported
the Agency's decision to apply the new strength requirement in final
paragraph (a)(7) prospectively (Ex. 189). In the second comment, Mr.
Richard Willis, of Southern Company, questioned how employers would
calculate the performance-based maximum intended load for step bolts in
final paragraph (a)(7) (Ex. 192). He recommended:

    We suggest that the methodology of National Electric Safety Code
(NESC) 2007 Rule 261N be adopted. We also feel that OSHA needs to
state a failure criteria for 1910.24(a)(7). . . .
    Instead of using the four times the maximum intended load, OSHA
should consider using the criteria of the NESC or IEEE 1307 (Ex.
192).

    OSHA recognizes the methodologies in the national consensus
standards that Mr. Willis recommended are methodologies employers can
use to determine and ensure that step bolts are capable of supporting
four times the maximum intended load. Employers are free to use the
NESC and IEEE 1307 standards, which OSHA referenced in the proposed
rule (75 FR 28901) in determining whether their step bolts are capable
of supporting four times the total load they reasonably anticipate
placing on the step bolt. In a 2003 letter of interpretation, OSHA
wrote, ``We believe in most situations an employer's compliance with
IEEE 1307-1996 will usually prevent or eliminate serious hazards''
(OSHA letter to Mr. Brian Lacoursiere, May 5, 2003).\21\
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    \21\ Available from OSHA's website at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=24564.
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    Under the performance based final rule, employers may use other
methods to ensure step bolts comply with the strength requirement in
final paragraph (a)(7). For example, employers may select step bolts
that manufacturers test according to the strength requirements
specified by the ANSI/TIA 222-G

standard (Section 12.4), and then ensure that workers do not place a
total load on the step bolts that exceeds the specified strength
limits.
    Mr. Willis also said that OSHA should state the failure criteria
for final paragraph (a)(7) as: ``If the intent is a 15 degree
deflection as referenced by the NESC and in 1910.24(a)(9), then this
should be stated'' (Ex. 192). OSHA does not believe it is necessary to
put additional language in final paragraph (a)(7) specifying a
``failure criteria'' for step bolt strength. First, the Agency believes
that final paragraph (a)(9) makes clear that step bolts bent more than
15 degrees do not meet the requirement in paragraph (a)(7). Final
paragraph (a)(9) states that employers must remove and replace those
step bolts. Second, the language Mr. Willis recommended is not
performance based as it does not include other failure criteria
manufacturers and employers may use. Therefore, OSHA finalizes the
provision as discussed.
    Final paragraph (a)(8) requires that employers ensure step bolts
are inspected at the start of each work shift and maintained in
accordance with Sec.  1910.22. By including the reference to Sec.
1910.22, OSHA is emphasizing that step bolts, like all walking-working
surfaces, must meet the general requirements in the final rule.
    OSHA believes a visual inspection often can reveal structural and
other problems with step bolts that may make them unsafe for workers to
use. Employers must correct, repair, or replace step bolts with
structural problems (e.g., broken, fractured, loose, bent, or corroded
step bolts) that indicate that the step bolts cannot support the
maximum intended load (final Sec.  1910.22(b) and (d)(2)). A visual
inspection also can identify whether step bolts are dry, or likely to
be slippery because of snow, ice, or rain (final Sec.  1910.22(a)(2)).
Final paragraph (a)(8) requires that employers address these conditions
to maintain step bolts in accordance with Sec.  1910.22.
    As with the inspection requirements in final Sec.  1910.22, the
inspection of step bolts most often will consist of a short, visual
observation of the condition of the step bolts. Final paragraph (a)(7)
permits workers to perform this visual inspection as they begin to
climb the structure, so long as the workers inspect the step bolts
before stepping on, or grasping them, and know not to proceed if the
step bolts do not pass the visual inspection. Where a worker or
supervisor identifies a problem during a visual inspection, a more
thorough examination may be necessary. The employer must repair,
correct, or replace the damaged or hazardous step bolt before allowing
workers to continue climbing the structure.
    OSHA notes the proposed rule, like 1990 proposed Sec.
1910.24(c)(4), specified that employers inspect step bolts visually
``before each use.'' The phrase ``before each use'' means before the
worker climbs the step bolts for the first time at the start of the
work shift. It does not mean that employers must, throughout a work
shift, have workers inspect the step bolts each time they climb them.
OSHA understands that workers may climb step bolts multiple times
during a work shift, and believes that inspecting step bolts at the
initial climb is sufficient. OSHA did not receive any comments on the
inspection requirement and adopts the requirement as discussed.
    Final paragraph (a)(9), like the proposed rule, requires that
employers ensure any step bolt that is bent more than 15 degrees from
the perpendicular, in any direction, is removed and replaced with a
bolt that meets the requirements of the section, before a worker uses
it. OSHA believes this provision is necessary because step bolts bent
to such a degree are not safe for workers to use. Regardless of the
direction of the bend, it could cause the worker to slip or fall off
the step bolt. If the bend in a step bolt is more than 15 degrees below
horizontal, a worker's feet may slip or slide off the end of the step
bolt. If the bend in a step bolt extends upwards more than 15 degrees,
it is likely to reduce the minimum clear step width (4.5 inches)
necessary to ensure the worker has a secure and safe foothold (final
paragraph (a)(4)).
    The final rule also requires that employers ensure that step bolts
used for replacement meet the all of the requirements of final
paragraph (a). This requirement will ensure that replacement step bolts
provide workers with the maximum level of protection afforded by
paragraph (a).
    OSHA drew final paragraph (a)(9) from 1990 proposed Sec.
1910.24(c)(5). OSHA did not receive any comments on paragraph (a)(9),
and adopts it as discussed.
Paragraph (b)--Manhole Steps
    Final paragraph (b) addresses the design, capacity, and use of
manhole steps. There are no requirements specifically addressing
manhole steps in existing subpart D, although OSHA's Telecommunications
standard establishes requirements to protect workers who use metal
ladders in manholes (Sec.  1910.268(h)(8)). OSHA drew most of the
manhole step requirements from the 1990 proposed Walking and Working
Surfaces and Personal Protective Equipment (Fall Protection Systems)
standard (55 FR 13360), which drew its requirements from a 1989
proposed rule on Electric Power Generation, Transmission, and
Distribution. OSHA did not believe that it was necessary to include the
manhole step requirements in the Electric Power Generation,
Transmission, and Distribution final rule because the 1990 proposed
rule to revise subpart D included provisions on manhole steps.
    Final paragraph (b)(1), like the proposed rule, requires that
employers ensure manhole steps are capable of supporting their maximum
intended load, as defined in Sec.  1910.21(b). As mentioned in the
discussion of final paragraph (a)(6), final Sec.  1910.22(b) requires
that employers ensure all walking-working surfaces are able to support
the maximum intended load that employers reasonably anticipate placing
on them. Final paragraph (b)(1) emphasizes that the maximum intended
load requirement in the final rule applies to existing manhole steps,
regardless of when the employer installed them. Manhole steps that
cannot support the maximum intended load without failure are not safe
to use.
    OSHA based the provision on 1990 proposed Sec.  1910.24(c)(2),
which also specified that existing manhole steps be capable of
supporting their maximum intended load. The ASTM C 478 standard
requires vertical and horizontal load testing of manhole steps in
accordance with ASTM Test Methods C 497 (Section <IP_ADDRESS>) (Ex. 382).
    Final paragraph (b)(1), like final paragraph (a)(6) of this section
and final Sec.  1910.22(b), is performance based. However, employers
are free to use the test procedures in ASTM C 478 and C 497 in
determining whether their manhole steps can support the maximum
intended load the employer anticipates placing on them. OSHA did not
receive any comments on this provision, and adopted it as proposed wit
minor editorial revisions.
    Final paragraph (b)(2), like the proposal, establishes requirements
for manhole steps installed on or after the effective date of the final
rule. OSHA based most of these requirements on 1990 proposed Sec.
1910.24, and ASTM C 478-13, with many of the manhole step requirements
in 1990 proposed Sec.  1910.24 applying only prospectively (e.g., 1990
proposed Sec.  1910.24(b)(6), (b)(7), and (c)(3)(i)-(iv))). As
mentioned earlier, OSHA believes that applying the manhole step
requirements when employers install new or replacement steps is the
most efficient and least disruptive way to implement the

requirements in final paragraph (b)(2). Manhole steps, compared to step
bolts, are generally more expensive to replace, and such replacement
may not be necessary when the manhole steps can support the maximum
intended load, and the employer inspects them at the start of each work
shift, and repairs or replaces them immediately after identifying
damage or hazardous conditions.
    Final paragraph (b)(2)(i), like the proposed rule, requires that
employers ensure manhole steps have a corrugated, knurled, dimpled, or
other surface that minimizes the possibility of a worker slipping. The
final rule is consistent with the requirements for metal manhole
ladders in OSHA's Telecommunications standard (Sec.
1910.268(h)(8)(v)). The 1990 proposed rule (proposed Sec.
1910.24(b)(7)) specified the same requirement as final paragraph
(b)(2)(i) for manhole steps.
    OSHA believes this final rule is necessary to reduce workers' risk
of slipping and falling. Underground manholes often have moisture and
other slippery substances (e.g., mud, grease) that can pose slip
hazards for workers. Ensuring that workers have, and can maintain, a
secure foothold when entering the manhole and climbing the manhole
steps is important to protect them from injury. OSHA notes final
paragraph (b)(2)(i) is performance based. Thus employers are free to
use any type of surface preparation that effectively minimizes the risk
of slipping. OSHA received no comments on the proposed provision and
adopts the requirement as discussed.
    Final paragraph (b)(2)(ii), like the proposal and final paragraph
(a)(1) of this section for step bolts, requires that employers ensure
manhole steps are constructed of, or coated with, material that
protects against corrosion if the manhole steps are in an environment
where corrosion may occur. The final rule is consistent with the
Telecommunications standard (Sec.  1910.268(h)(8) introductory text and
(h)(8)(vi)) and 1990 proposed Sec.  1910.24(b)(6)). The
Telecommunications standard also requires that employers, when
selecting metal ladders, ensure that the ladder hardware must be
constructed of a material that is protected against corrosion and that
the metals used shall be selected as to avoid excessive galvanic action
(Sec.  1910.268(h)(8)(vi)). The ASTM C 478 standard, however, addresses
corrosion hazards using a different approach. The national consensus
standard does not require that manhole steps consist of corrosion-
resistant materials or have corrosion-resistant coatings. Instead, it
requires that ferrous metal steps not painted or treated to resist
corrosion must have a minimum cross-sectional dimension of one inch.
OSHA believes that requiring all manhole steps to consist of corrosion-
resistant material or have corrosion-resistant coatings is more
protective, and better effectuates the purposes of the OSH Act, than
ASTM C 478. OSHA's final rule protects manhole steps from becoming
corroded, while the ASTM C 478 standard requires that employers make
ferrous metal steps with large cross-sectional dimensions so they will
hold up against corrosion longer.
    Furthermore, as discussed in final paragraph (a)(1) of this section
for step bolts, OSHA believes that corrosive environments can weaken
and cause damage to unprotected metals, including manhole steps.
Corrosion resistance will help to prevent deterioration that can lead
to failure of manhole steps. OSHA did not receive any comments on the
provision and adopts it as proposed with minor editorial
clarifications.
    Final paragraph (b)(2)(iii), like the proposed rule, requires that
employers ensure manhole steps have a minimum clear step width of 10
inches. The final rule is consistent with the ASTM C 478 standard
(Section 16.5.2), as well as 1990 proposed Sec.  1910.24(b)(2). The
ASTM C 478 standard has been in place for many years, so OSHA believes
that most manhole steps have a step width of at least 10 inches. OSHA
did not receive any comments on paragraph (b)(2)(iii) and adopts it as
proposed.
    Final paragraph (b)(2)(iv), like the proposal, requires that
employers ensure manhole steps are uniformly spaced at a vertical
distance of not more than 16 inches apart, measured center to center
between steps. As mentioned above, OSHA believes that uniform spacing
helps to make climbing safe. The ASTM C 478 standard specifies a
maximum vertical spacing of 16 inches. The 1990 proposed provision
(proposed Sec.  1910.24(b)(1) specifies a uniform spacing of not less
than six inches nor more than 18 inches apart.
    Final paragraph (b)(2)(iv), like final paragraph (a)(3) of this
section for step bolts, also allows spacing from the entry and exit
surface to the first manhole step to be different from the spacing
between the other steps. Additionally, OSHA added a standard method for
measuring the distance--from center to center between steps. This
measurement method and the allowance for different spacing of the first
manhole step are common practices, and will provide the consistency
needed to help protect workers, who will be entering, exiting, and
working in different manholes. OSHA did not receive any comments on
this provision and adopts it as discussed.
    Final paragraph (b)(2)(v), like the proposed rule, requires that
employers ensure manhole steps have a minimum perpendicular distance of
at least 4.5 inches measured between the centerline of the manhole step
and the nearest permanent object in back of it. The minimum clear-
distance requirement is consistent with 1990 proposed Sec.
1910.24(b)(3) and ASTM C 478, indicating that 4.5 inches is the common,
accepted clearance for manhole steps. This requirement will provide
adequate foot and hand holds, which are necessary for workers to safely
climb manhole steps. OSHA did not receive any comments on this
provision and adopts it as proposed.
    Final paragraph (b)(2)(vi), like the proposal and final paragraph
(a)(2) of this section for step bolts, requires that employers ensure
that manhole steps are designed, constructed, and maintained to prevent
the worker's foot from slipping or sliding off the end of the manhole
step, which can result in a fall or slip. The final rule is the same as
1990 proposed Sec.  1910.24(b)(5).
    The proposed rule specified that manhole steps be designed to
prevent workers' feet from slipping off the end of the step. For the
same reasons discussed above in final paragraph (a)(2) for step bolts,
OSHA added ``constructed and maintained'' to the final rule. OSHA did
not receive any comments on this provision and adopted it as revised.
    Final paragraph (b)(3), like the proposed rule and final paragraph
(a)(8) of this section for step bolts, requires that employers ensure
manhole steps are inspected at the start of the work shift, and
maintained in accordance with Sec.  1910.22. 1990 proposed Sec.
1910.24(c)(4) specified that manhole steps be maintained in a safe
condition and visually inspected prior to each use. OSHA's reasons for
requiring manhole step inspections at the start of each work shift are
the same reasons as those discussed above in final paragraph (a)(8)
and, therefore, are not repeated here.
    The proposed rule specified that manhole steps be visually
inspected before each use. Mr. Miller, of Ameren, objected to the
proposed language, saying: ``Manhole steps are inspected when entered.
There should be no need for additional inspection which would only
increase the time and have little to no impact on safety. This seems
only to be a paperwork requirement and would

do little to protect workers from hazards'' (Ex. 189).
    OSHA is unclear what Mr. Miller means by ``additional inspection,''
specifically whether he is referring to the ``before each use''
language in the proposed rule or the requirement that employers also
maintain manhole steps in accordance with final Sec.  1910.22, which
requires inspection of walking-working surfaces regularly and as
necessary. The ``before each use'' language means that employers must
ensure inspection of manhole steps before the first use in a work
shift, and not every time a worker climbs on manhole steps. OSHA
recognizes that workers may climb manhole steps multiple times during a
work shift, and believes that inspecting the manhole steps when workers
first use them during a work shift is sufficient. The final rule
clarifies this point.
    If Mr. Miller is referring to the inspections of walking-working
surfaces employers must conduct in accordance with Sec.  1910.22(d)(1),
OSHA disagrees with Mr. Miller that such inspections are simply a
paperwork burden that have no impact on safety. Conducting regular
inspections ensures that hazards are identified and corrected in a
timely manner, thereby preventing worker injury or death. Regular
inspections also are important if workers do not use manhole steps
daily or frequently. Inspections provide the assurances that walking-
working surfaces such as manhole steps will be in a safe and useable
condition when workers use them.
    By contrast, the American Federation of State, County and Municipal
Employees (AFSCME) recommended that OSHA strengthen the visual
inspection requirement for existing manhole steps: ``Our members report
that many of these steps degrade due to exposure to the elements and
are difficult to inspect visually. Often manholes are not entered
regularly. We suggest the Agency require inventory of manholes that use
permanent step ladders and that they be inspected annually'' (Ex. 226).
OSHA believes that the level of inspection the final rule requires
provides far more protection than AFSCME recommends for existing
manhole steps. Final paragraph (b)(3) requires that employers ensure
each manhole step is inspected at the start of each work shift, which
could amount to multiple inspections each workday, depending on the
number of work shifts in a workday. OSHA believes that requiring
inspection before initially using manhole steps in a work shift is more
protective than using manhole steps that were last inspected almost a
year ago.
    Final paragraph (b)(3) also requires that employers maintain
manhole steps in accordance with final Sec.  1910.22. That section
requires employers to inspect walking-working surfaces regularly and as
necessary, and to maintain them in safe condition. ``Regular
inspection'' means that the employer has some type of schedule, formal
or informal, for inspecting walking-working surfaces that is adequate
to identify hazards and address them in a timely manner. For purposes
of the final rule, ``as necessary'' means that employers must conduct
inspections when particular workplace conditions, circumstances, or
events occur that warrant an additional check of walking-working
surfaces to ensure that they are safe for workers to use. For example,
an additional inspection may be necessary to ensure that a significant
leak or spill does not create a slip, trip, or fall hazard on a
walking-working surface.
    OSHA believes this combination of inspection requirements will
ensure that employers identify and correct hazardous conditions, such
as degradation due to corrosion, on a timely basis, even if workers do
not use manhole steps regularly. In addition, the requirement that
manhole steps must be capable of supporting the maximum intended load
(Sec.  1910.22(b)) will supplement visual inspections to ensure that
manhole steps are safe to use.
Section 1910.25--Stairways
    Section 1910.25 of the final rule establishes requirements for the
design and installation of stairways. OSHA carried forward the majority
of these requirements from the existing rule (Sec.  1910.24, Fixed
industrial stairs), and also drew a number of provisions from the
following national consensus standards:
     American Society of Safety Engineers/American National
Standard Institute (ASSE/ANSI) A1264.1-2007, Safety Requirements for
Workplace Walking/Working Surfaces and Their Access; Workplace, Floor,
Wall and Roof Openings; Stairs and Guardrail Systems (A1264.1-2007)
(Ex. 13);
     National Fire Protection Association (NFPA) 101-2012, Life
Safety Code (NFPA 101-2012) (Ex. 385); and
     International Code Council (ICC) International Building
Code-2012 (IBC-2012) (Ex. 386).
    Final Sec.  1910.25 is titled ``Stairways,'' which replaces the
``Fixed Industrial Stairs'' title in the existing rule (see discussion
of ``fixed industrial stairs'' below). The final rule (Sec.
1910.21(b)) defines a stairway as ``risers and treads that connect one
level with another, and includes any landings and platforms in between
those levels.'' Final Sec.  1910.25, like the proposed rule, covers all
stairways, including standard, ship, spiral, and alternating-tread type
stairs, used in general industry (Sec.  1910.25(a)). OSHA organized
final Sec.  1910.25 by the types of stairways that the final rule
covers, and revised the format to add a separate paragraph identifying
the scope and application of the section, as follows:
     Paragraph (a), Application, which specifies the stairs the
final rule covers and excepts;
     Paragraph (b), now titled General Requirements, which
establishes the requirements that apply to all covered stairways;
     Paragraph (c), Standard Stairs; and
     Paragraphs (d) through (f), which specify requirements
when employers use spiral stairs, ship stairs, and alternating tread-
type stairs.

OSHA believes this revised format makes final Sec.  1910.25 easier to
understand and follow.
    Final Sec.  1910.25, like the proposal, replaces the term ``fixed
industrial stair'' in the existing rule with the plain-language term
``stairways.'' In addition, in final Sec.  1910.25, OSHA uses the term,
``standard stairs,'' that Sec.  1910.21(b) defines as ``a fixed or
permanently installed stairway.'' In the proposed rule, the Agency
explained that ``fixed industrial stairs'' was the term in use when
OSHA adopted the existing rule in 1971 from ANSI A64.1-1968 (now
A1264.1-2007). The Agency said ``standard stairs'' was easier to
understand and consistent with revised and updated national consensus
standards (A1264.1-2007, NFPA 101-2006) and industry codes (IBC-2003)
(75 FR 28881-82). Those standards and codes used ``standard stairs,''
``stairways,'' and ``fixed stairs'' interchangeably, and none used or
defined ``fixed industrial stairs.''
    OSHA requested comment about replacing the term ``fixed industrial
stairs,'' particularly whether it would cause confusion or leave a gap
in coverage. OSHA only received one comment from the National Fire
Protection Association (NFPA), which supported the proposed change (Ex.
97). NPFA said standard stairs was consistent with NFPA 101-2009
(Sections 3.1 and <IP_ADDRESS>.1). OSHA believes it is important to update
terminology so standards are easy to understand and reflect current
industry practice.

Paragraph (a)--Application
    As mentioned, OSHA changed the title of final paragraph (a) to
``Application.'' OSHA believes that ``Application'' better describes
the content of paragraph (a), which identifies what stairways the final
rule covers and excludes. Final paragraph (a) is broad and
comprehensive. The scope of the existing rule, Sec.  1910.24(a), which
covers ``interior and exteriors stairs around machinery, tanks, and
other equipment, and stairs leading to or from floors, platforms, or
pits,'' also is comprehensive. However, OSHA believes the language in
the final rule more clearly and fully explains the Agency's objective,
and ensures that the final rule does not inadvertently exclude any type
of stairway used in general industry.
    Final paragraph (a) also lists certain stairways that Sec.  1910.25
does not cover, specifically:
     Stairs serving floating roof tanks;
     Stairs on scaffolds;
     Stairs designed into machines or equipment; and
     Stairs on self-propelled motorized equipment (e.g., motor
vehicles, powered industrial trucks).
    Stairs serving floating roof tanks. As discussed in the proposed
rule, these types of stairs are not covered by recognized industry
standards and the Agency does not have any information or sufficient
evidence on how to regulate these stairs. OSHA requested information on
these types of stairs in the proposed rule and did not receive comment.
Therefore, OSHA has not included stairs serving floating roof tanks in
the scope of this section.
    Stairs on scaffolds. Final paragraph (a) retains the proposed
exemption for stairs on scaffolds. Requirements for stairs on scaffolds
are provided in the construction industry standards in Sec.  1926.451.
In the preamble to the proposed rule, the Agency explained that the
purpose of the proposed exemption was to have employers comply with the
requirements for stairs on scaffolds contained in Sec.  1926.451. OSHA
said the proposed approach would increase consistency among its
standards, assist employers who perform both general industry and
construction work, and minimize potential for confusion. This exemption
is consistent with OSHA's approach in final Sec.  1910.27(a) for
scaffolds used in general industry. OSHA believes that having employers
who use scaffolding follow a single standard will reduce confusion and
help ensure worker safety.
    Stairs designed into machines or equipment and stairs on self-
propelled motorized equipment. Final paragraph (a) retains the proposed
exemption from final Sec.  1910.25 for stairs designed into machines or
equipment and stairs on self-propelled motorized equipment, such as
motor vehicles and powered industrial trucks. However, OSHA does not
intend this exemption to apply to equipment that the existing standard
(Sec.  1910.24) currently covers. For example, the exemption does not
apply to equipment such as mobile well-servicing rigs \22\ that are
transported to various oil and gas wells (Delta Drilling Co. v. OSHC,
91 F.3d 139 (5th Cir. 1996) (unpublished); Basic Energy Services, 25
BNA OSHC 1811 (No. 14-0542, 2015); Poole Co., Texas Ltd., 19 BNA OSHC
1317 (No. 99-0815, 2000)).
---------------------------------------------------------------------------

    \22\ A mobile well-servicing rig, also referred to as a
``workover rig,'' consists of ``a telescoping derrick; . . .
articulating platforms to allow for differences in the respective
well sites to which the rig travels; as well as many other
implements that aid in the maintenance and upkeep of an existing
well'' (Basic Energy Services, 25 BNA OSHC 1811 (No, 14-0442,
2015)). Once the rig is placed on ``stable ground'' over the well
head, the ``rig-up'' process begins (Id.). ``[T]he platforms of the
mobile well servicing rig are attached to the base of a derrick,
which is a part of the drilling rig itself . . . The servicing
units, though mobile, are placed on stands while in use . . . [T]he
sole purpose of the [well-servicing rig] is to serve as a work
platform'' (Poole Co., Texas Ltd., 19 BNA OSHA 1317 (No. 99-0815,
2000)). The rigging-up process also includes installation of
guardrails, stairs and other implements related to ingress/egress
and safety'' (Id.).
---------------------------------------------------------------------------

    The exemption for stairs designed into machines or equipment and
stairs on self-propelled motorized equipment is consistent with the
scope of A1264.1-2007 and other national consensus standards, none of
which address those stairs either. In the proposed rule, the Agency
explained that it did not have sufficient information about such
stairs, and there were no national consensus standards or industry
codes to turn to for guidance or best industry practices. Although OSHA
requested comment and information, only the Society of Professional
Rope Access Technicians (SPRAT) responded:

    It is the recommendation of this commenter that any stairs not
covered by recognized industry standards, and about which the Agency
does not have sufficient information or evidence to regulate, simply
be acknowledged as a potentially hazardous situation with provision
for protection against falls required (Ex. 205).

SPRAT pointed out that IBC-2009 and A1264.1-2007 only cover stairs
associated with buildings, and the scope and requirements of those
standards do not include stairs on machines or equipment. Given that,
SPRAT said it would be inappropriate for OSHA to use those standards to
justify covering stairs on, or designed into, machines and equipment.
SPRAT also argued that the rulemaking record did not have adequate
information to support regulating such stairs. OSHA agrees with SPRAT
and retains the exemption for those reasons.
    Although final Sec.  1910.25 does not apply to stairs designed into
machines or equipment or stairs on self-propelled motorized equipment,
OSHA notes that the OSH Act's requirement that employers provide their
workers with a place of employment that is free from recognized hazards
that are causing, or are likely to cause, death or serious physical
harm continues to apply (see 29 U.S.C. 654(a)(1)).
    Final paragraph (a) eliminates the following existing exceptions:
    Stairs to construction operations at private residences,
articulated stairs installed on dock facilities and stairs used for
fire exit purposes. Final Sec.  1910.25 does not include the existing
exemption for stairs to construction operations in private residences,
and the exemption for articulated stairs installed on dock facilities.
OSHA believes that, by specifying that final Sec.  1910.25 only applies
to stairs used in general industry it is no longer necessary to retain
exemptions for stairs in construction operations in private residences
or articulated stairs installed on dock facilities since general
industry does not use such stairs. OSHA's construction (29 CFR part
1926) and maritime (29 CFR parts 1915, 1917, and 1918) standards
regulate these two types of stairs as stairs used for fire-exit
purposes.
    OSHA also did not include the existing exemption for stairs used
for fire exit purposes in either the proposed or final rules for two
reasons. First, OSHA recognizes that employers could use virtually all
stairways for fire and emergency exits, which makes a special provision
for fire-exit stairs unnecessary. Second, when workers use stairways to
exit an area in the event of a fire, it is important that the stairways
meet the safety requirements in Sec.  1910.25 so workers are able to
safely escape. The Agency notes that its Means of Egress standards (29
CFR part 1910, subpart E) supplement walking-working surfaces
requirements, including those in Sec.  1910.25, for those portions of
exit routes, including stairways, that are ``generally separated from
other areas to provide a protected way of travel to the exit
discharge'' (29 CFR 1910.43(c)).
Paragraph (b)--General Requirements
    Paragraph (b) of the final rule sets forth general requirements for
all stairways covered by this section, while other provisions of Sec.
1910.25 specify

requirements for specific types of stairways. The general requirements
in the existing rule (29 CFR 1910.23 and 1910.24) only apply to fixed
industrial stairs. However, OSHA believes it is necessary to apply
these general requirements to all stairways used in workplaces to
ensure that workers have adequate protection from fall hazards.
    Final paragraph (b)(1), like proposed paragraph (a)(2), requires
that employers ensure handrails, stair rail systems, and guardrail
systems are provided in accordance with final Sec.  1910.28. This
provision is intended to protect workers from falling off stairways.
The final rule revises the proposal in two ways. First, OSHA added
``guardrail systems'' to final paragraph (b)(1). There are places on
stairways, such as a platform between two flights of stairs, where
guardrails, not stair rail systems are used. This was OSHA's intent in
the proposed rule and is clarified for the final rule. There is no
additional burden imposed on employers because they already must
provide protection on unprotected sides and edges 4 feet or more above
a lower level in accordance with final Sec.  1910.28. Section 1910.29
of the final rule details the criteria these guardrail systems must
meet.
    Second, the Agency did not include the note from proposed paragraph
(a)(2) in final paragraph (b)(1). The note was moved to Sec.
1910.29(f)(1)(iii) in the final rule. The proposed note specified that
the top rail of a stair rail system may also serve as a handrail when
installed in accordance with Sec.  1910.29(f). The Agency determined
that the note primarily addresses criteria for stair rail systems and
is more appropriately placed with the criteria requirements in Sec.
1910.29. OSHA did not receive any comments on the proposed provision
and adopted the provision with the clarifications discussed above.
    Final paragraph (b)(2), like proposed paragraph (a)(3), requires
employers to ensure that the vertical clearance above any stair tread
to any overhead obstruction is at least 6 feet, 8 inches, as measured
from the leading edge of the tread. Like the proposal, spiral stairs
must meet the vertical clearance requirement specified by final
paragraph (d)(3), which is 6 feet, 6 inches.
    The required vertical clearance in the final rule is lower than the
7-foot minimum clearance in the existing requirement (Sec.
1910.24(i)). However, the 6-foot, 8-inch clearance is consistent with
A1264.1-2007 (Section 6.12) and NFPA 101-2012. OSHA notes that Section
6(b)(8) of the Occupational Safety and Health Act of 1970 (OSH Act) (29
U.S.C. 655(b)(8)) requires OSHA to promulgate rules that are consistent
with existing national consensus standards or explain why differences
better effectuate the purpose of the OSH Act. The Agency believes that
the requirements in A1264.1-2007 and NFPA 101-2012 provide adequate
protection and reflect accepted industry practice. OSHA also points out
that stairways built in compliance with the existing clearance
requirements already meet the final rule. OSHA did not receive any
comments on the proposed provision.
    Final paragraphs (b)(3) through (5) establish requirements for
riser heights, tread depths, and stairway landing platform dimensions.
The final paragraphs, which are consistent with existing subpart D, are
the minimum criteria necessary to ensure worker safety when using
stairs. The final provisions also contain minor non-substantive changes
to increase clarity.
    Final paragraph (b)(3), like proposed paragraph (a)(4),
incorporates the requirement in existing Sec.  1910.24(f) that
employers ensure that stairs have uniform riser heights and tread
depths between landings. OSHA believes that retaining this requirement
is necessary because, in the Agency's experience, even small variations
in riser height can cause trips.
    OSHA, however, is not carrying forward other language in existing
Sec.  1910.24(f). For example, the existing rule requires that
employers ensure stair treads and nosings are slip-resistant. OSHA does
not believe this provision is necessary because final Sec.  1910.22
already addresses this hazard. To illustrate, Sec.  1910.22(a)(3)
requires employers to maintain walking-working surfaces free of hazards
such as spills, and Sec.  1910.22(d)(1) requires employers to maintain
walking-working surfaces in a safe condition. Therefore, OSHA is not
repeating this requirement in final Sec.  1910.25.
    Similarly, OSHA believes it is not necessary to include in final
Sec.  1910.25(b)(3) the existing language allowing employers to use
``welded bar grating treads without nosings.'' The final rule is
performance-based so employers are free to use stairways constructed of
any type of material that will meet the requirements of the final rule.
    OSHA received comments on the proposed provision. In particular,
NFPA argued that the uniform tread and riser dimensions in final
paragraph (b)(3) are not achievable because the provision does not
include construction tolerances. NFPA stated, ``It is not technically
possible to build stairs with consistent riser height and consistent
tread depth as construction tolerances creep into the process'' (Ex.
97). To address this issue, NFPA recommended that OSHA incorporate the
tolerances allowed in NFPA 101-2009, which permits an allowance of no
more than \3/16\ inches in adjacent tread depth or riser height, and a
tolerance of no more than \3/8\ inches between the largest and smallest
tread or riser in any flight of stairs. NFPA stated that the
recommendation would provide a ``safety net for compliance'' and would
protect employers from an interpretation of ``uniform'' that does not
permit any allowance for construction tolerances, or that permits
tolerances that are less than the tolerances established in NFPA 101-
2009 (Ex. 97).
    OSHA believes that minor variations in tread depth and riser
height, such as those allowed in NFPA 101-2012 and A1264.1-2007, are
acceptable. OSHA understands that minor variations in tread depth and
riser height due to construction tolerances are likely to occur when
building stairs and these minor variations are acceptable under the
final rule.
    Final paragraph (b)(4), like proposed paragraph (a)(5) and existing
Sec.  1910.24(g), requires that employers ensure the size of stairway
landings and platforms is not less than the stair width and not less
than 30 inches in depth, as measured in the direction of travel. The
final rule is consistent with A1264.1-2007 (Section 6.10). OSHA did not
receive any comments on the proposed provision adopts the proposed
language with only minor clarifications.
    Final (b)(5), like proposed paragraph (a)(6), requires that, when a
door or a gate opens directly onto a stairway, employers must provide a
platform and ensure the swing of the door or gate does not reduce the
effective usable depth of the platform to less than:
     20 inches for platforms installed before the effective
date of the final rule; and
     22 inches for platforms installed on or after the
effective date of the final rule.
    The final and proposed rules revise the language of the existing
rule (Sec.  1910.23(a)(10)), which requires employers to ensure that
doors or gates do not reduce the effective usable depth to less than 20
inches, by increasing the effective usable platform depth by 2 inches
for newly installed platforms. The final rule grandfathers in the 20-
inch platform depth requirement for existing stairways. Increasing the
platform depth requirement to a minimum 22 inches is consistent with

the current and earlier versions of A1264.1 (1995, 2002, and 2007).
    The final and proposed rules use the term ``effective usable
depth.'' The term means the portion of the platform that is beyond the
swing of the door or gate where a worker can stand when opening the
door or gate. As Figure D-7 in the regulatory text illustrates, the
effective useable depth is that portion of the platform that extends
beyond the swing radius of the door or gate when it is open fully to
the leading edge of the stair. OSHA believes this term expressly
clarifies that the minimum platform depth must consider the portion of
the platform used to accommodate the swing of the door or gate.
    The Agency requested comment on the proposed provision and the
amount of unobstructed space necessary for landing platforms when doors
or gates open directly onto them. Ameren Corporation commented:

    The necessary landing outside the swing radius of any door is
directly dependent upon the direction of the door's swing in
relation to the direction of travel. If the door opens in the
direction of travel, much less clearance is needed for the employee.
Since no objective evidence is available for one distance for all
paths of travel, the clearance of door swing should remain as is and
allow the employer to determine whether or not two more inches of
clearance is necessary for the safety of their personnel (Ex. 189).

    OSHA believes that adopting the 22-inch effective useable platform
depth for newly installed stair platforms is appropriate. As mentioned
earlier, OSHA drew the requirement from the A1264.1-2007 standard. The
standard reflects the considered views of employers, employees, safety
professionals, and others. The 22-inch requirement also was in the 1995
and 2002 editions of the A1264.1 standard. With the requirement in
A1264.1-2007 being in effect since 1995, OSHA believes it clearly
represents accepted industry practice. OSHA notes the 22-inch
effective-depth requirement applies to platforms installed on or after
the effective date of the final rule, which is January 17, 2017. OSHA
believes that the phase-in time the final rule allows is more than
adequate for employers who install platforms, gates, and doors on
stairways.
    Ameren Corporation also raised an issue about the compliance
deadline for paragraph (b)(5):

    Lead time for material orders are often quite longer than three
months[,] often up to years to order material for large capital
projects. Small projects with possibly only a small amount of
material being required shouldn't have much of an issue of complying
depending on the manufacturer capabilities and their imposed
deadlines. Stipulations of ``ordered'' material should be imposed in
regard to the date of the final rule because the time between
ordering and placing into service is often greater than 90 days (Ex.
189).

    The 22-inch platform depth requirement in the final rule is
prospective: it only applies to stairways, platforms, doors, and gates
installed on or after the effective date of the final rule, which is
January 17, 2017. This provision gives employers a 60-day lead time
after publication of the final rule to come into compliance with the
requirement when they install new stairway platforms. OSHA does not
believe that it is necessary to extend the compliance deadline any
further, even though the Agency proposed 150 days. The Agency believes
a 60-day compliance lead time is more than adequate given that the 22-
inch requirement in the A1264.1 standard has been in place for more
than 18 years. During this 18-year period, OSHA believes the vast
majority of employers, as well as manufacturers, construction
companies, and building owners, came into compliance with the 22-inch
requirement. Therefore, OSHA requires employers to comply with the 22-
inch effective useable platform depth requirement by the standard's
effective date.
    Final paragraph (b)(6), like proposed paragraph (a)(7), requires
that employers ensure stairs can support at least five times the normal
anticipated live load, and never less than a concentrated load of 1,000
pounds, applied at any point on the stairway. This requirement is
consistent with A1264.1-2007 and earlier versions, which have been in
place for many years. OSHA believes that most existing stairs have been
installed in accordance with the ANSI requirements, and, therefore,
already are in compliance.
    OSHA requires employers to apply this safe-load requirement to
spiral stairs, ship stairs, and alternating tread-type stairs, as well
as standard stairs. OSHA believes the safe-load requirement is
necessary to protect workers from stair collapse due to overloading,
regardless of the type of stairs they are using. OSHA notes that final
paragraph (b)(6), like the ANSI standard, applies to all stairs that
Sec.  1910.25 covers.
    For the purposes of final paragraph (b)(6), a ``normal anticipated
live load'' means a dynamic load (e.g., temporary, of short duration,
or moving) that an employer reasonably anticipates will or could be
applied to the stairs (see letter to Mr. M. Podlovsky, May 8,
2000).\23\ A ``concentrated load,'' for the purposes of final paragraph
(b)(6), is the load-application point where the structure would
experience maximum stress. Thus, a normal live load is spread over the
whole stair tread area, while a concentrated load refers to a load
applied at one point on the stair tread.
---------------------------------------------------------------------------

    \23\ OSHA letter to Mr. Podlovsky available at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=23731.
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    Final paragraph (b)(6) includes revisions that OSHA believes will
provide an equal or greater level of protection to workers than the
existing and proposed rules. For example, final paragraph (b)(6)
requires that employers ensure stairways ``can support'' the required
load, while the existing (at Sec.  1910.24(c)) and proposed rules
specify that stairways must ``be designed and constructed'' to support
the required load. The revision ensures that, in addition to the design
and construction of the stairways, the employer has an ongoing duty to
maintain the stairways to ensure they can continue to support the load
applied to them without collapse.
    The final rule also revises the default strength language to
require that stairways be capable of supporting a concentrated load of
not less than 1,000 pounds ``applied at any point.'' The existing rule
requires that stairways be capable of carrying not less than a
``moving'' concentrated load of 1,000 pounds. OSHA believes the final
provision provides equal or greater level of safety by making the final
rule applicable to any single point on the stairs, particularly the
point that experiences maximum stress. These revisions are consistent
with A1264.1-2007. OSHA did not receive any comments on the proposed
provision and adopts paragraph (b)(6) with the changes discussed.
    Final paragraphs (b)(7) through (9) specify when and where
employers must provide standard stairs, and under what conditions
employers may use spiral, ship, or alternating tread-type stairs. In
final paragraphs (b)(7) and (8), OSHA simplified and reorganized the
existing rule (Sec.  1910.24(b)) to make the requirements clearer and
easier to understand than the existing and proposed rules.
    Final paragraph (b)(7), like proposed paragraph (a)(8) and existing
Sec.  1910.24(b), requires employers to provide standard stairs to
allow workers to travel from one walking-working surface to another.
The existing and final rules both recognize that standard

stairs are the principal means of providing safe access in workplaces
and employers must provide them when operations necessitate ``regular
and routine travel between levels,'' including accessing operating
platforms to use or operate equipment. The final provision is
consistent with A1264.1-2007 (Section 6.1).
    For purposes of the final rule, OSHA describes ``regular and
routine travel'' in much the same way as the existing rule in Sec.
1910.24(b). The term includes, but is not limited to, access to
different levels of the workplace daily or during each shift so workers
can conduct regular work operations, as well as operations ``for such
purposes as gauging, inspection, regular maintenance, etc.'' (existing
Sec.  1910.24(b)). ``Regular and routine'' also includes access
necessary to perform routine activities or tasks performed on a
scheduled or periodic, albeit not daily, basis, particularly if the
tasks may expose employees to acids, caustics, gases, or other harmful
substances, or require workers to manually carry heavy or bulky
materials, tools, or equipment (existing Sec.  1910.24(b)).
    Final paragraph (b)(7) retains the existing provision allowing the
use of winding stairways on tanks and similar round structures when the
diameter of the tank or structure is at least 5 feet. OSHA notes that
winding stairs on such tanks and structures still must meet the other
general requirements for stairways specified in the final rule. This
provision does not preclude the use of fixed ladders to access elevated
tanks, towers, and similar structures, or to access overhead traveling
cranes, etc., when the use of such ladders is standard or common
industry practice. OSHA received no comments on the proposed
requirement and adopted the provision with only minor editorial change.
    Final paragraph (b)(8) allows employers to use spiral stairs, ship
stairs, and alternating tread-type stairs (collectively referred to as
``non-standard stairs''), but only when employers can demonstrate that
it is not feasible to provide standard stairs.
    The existing rule (existing Sec.  1910.24(b)), which OSHA adopted
in 1972 from ANSI A64.1-1968 pursuant to section 6(a) of the OSH Act
(29 U.S.C. 655(a)), allows employers to use spiral stairs for ``special
limited usage'' or as a secondary means of access but only where it is
``not practical'' for employers to provide standard stairs. The
existing rule, however does not address either ship or alternating
tread-type stairs.
    The 1973 proposed rule would have allowed the use of ship stairs
``in restricted spaces in which a fixed industrial stairway cannot be
fitted'' (38 FR 24300, 24304 (9/6/1973)), however, OSHA withdrew that
proposal (41 FR 17227 (4/23/1976)). In a 1982 letter of interpretation,
though, OSHA said if employers use ship stairs in accordance with the
1973 proposal, the Agency would consider it to be a de minimis
violation of existing Sec.  1910.24(e) (Letter to Edward Feege, August
20, 1982 \24\).
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    \24\ Letter to Mr. Feege available from OSHA's Web site at:
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=19042.
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    That year OSHA issued Instruction STD 01-01-011 (April 26, 1982)
allowing the use of and establishing guidelines for ``a newly developed
alternating tread-type stair'' \25\ (See also, Letter to Mr. Dale
Ordoyne, December 2, 1981 \26\). To ensure worker safety, the
instruction stated that alternating tread-type stairs must be designed,
installed, used, and maintained in accordance with manufacturer's
recommendations. In addition, OSHA said alternating tread-type stairs
must meet the following requirements:
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    \25\ OSHA Instruction STD 01-01-011 is available from OSHA's Web
site at: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=1753.
    \26\ Letter to Mr. Ordoyne available from OSHA's Web site at:
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=18983.
---------------------------------------------------------------------------

     The stairs are installed at a 70 degree angle or less;
     The stairs are capable of withstanding a minimum uniform
load of 100 pounds per square foot with a design factor of 1.7 and the
treads are capable of carrying a minimum concentrated load of 300
pounds at the center of any treadspan or exterior arc with a design
factor of 1.7. If the alternating tread-type stairs are intended for
greater loading, the employer must ensure the stairs are constructed to
allow for additional loading; and
     The stairs are equipped with a handrail on each side to
assist employees climbing or descending the stairs.
    OSHA announced in both STD 01-01-011 and the 1982 letter of
interpretation that it would include provisions on ship stairs and
alternating tread-type stairs in the subpart D rulemaking. The 1990
proposal included provisions allowing employers to use spiral, ship,
and alternating tread-type stairs and establishing design
specifications for each type of stair (55 FR 13360, 13400 (4/10/1990)).
No final rule came from that proposal either.
    In 2002, in response to an Office of Management and Budget (OMB)
request for comment on its Draft Report to Congress on the Costs and
Benefits of Federal Regulations, the Copper and Brass Fabricators
Council (CBFC) urged OSHA to revise the existing rule (Sec.
1910.24(b)) to allow the use of ship and spiral stairs in a broader
range of situations:

    OSHA regulations under some circumstance require the use of
fixed ladders when spiral stairways or ship stairs would be safer .
. . [S]ection 1910.24(e) prohibits any stairs with an angle of rise
greater than 50 degrees. Unfortunately, it is very common to have a
tight location in industry where there is insufficient space for
stairs with an angle of 50 degrees or less. Traditionally, these
areas would use ship stairs that have separate handles from the
stair rail but steps that are less deep than the traditional 8 inch
to 12 inch step. Otherwise, a spiral stair was used which allowed a
deeper tread. Under the present regulation, industries are required
to use rung ladders in these locations which is less safe than
spiral stairs or ship stairs (Ex. 4).

    The 2010 proposed rule expanded the existing standard to allow
employers to use spiral, ship, and alternating tread-type stairs.
Similar to the existing rule, the proposal allowed employers to use
non-standard stairs for ``special limited usage'' and ``secondary
access,'' but only when the employer can demonstrate it is ``not
practical'' to provide standard stairs in either situation (proposed
paragraph (b)(9)). The proposed rule did not define any of these terms.
Also, A1264.1-2007 did not define ``special limited use,'' but OSHA
explained in the preamble to the proposed rule that the International
Building Code (IBC)-2009 identified ``special limited usage'' area as a
space that is no more than 250 square feet (23 m\2\) and serves no more
than five occupants'' (75 FR 28882). The IBC-2009 also identifies
``galleries, catwalks and gridirons'' as examples of special limited
usage areas (75 FR 28882).
    Final paragraph (b)(8) differs from the proposed rule in several
ways. First, final paragraph (b)(8) deletes the language in the
proposed rule limiting the use of non-standard stairs to ``special
limited usage'' areas and as a secondary means of access. Although the
existing, proposed, and A1264.1-2007 standards permit employers to use
non-standard stairs in special limited usage areas and for secondary
access, none of these standards defines either term. OSHA believes
eliminating those undefined terms makes the final rule easier to
understand.
    Second, the final rule replaces the proposed language (i.e.,
``special limited usage and secondary access situations

when the employer can demonstrate it is not practical to provide a
standard stairway'') with long-standing and familiar performance-based
language (i.e., ``can demonstrate that it is not feasible to use
standard stairs''). The language in the final rule is consistent with
the legal requirements of the OSH Act. In addition, OSHA believes that
the language in the final rule gives employers greater flexibility. For
example, there may be places other than special limited use areas and
secondary access situations where an employer can demonstrate that
standard stairs are infeasible. The final rule allows employers to use
non-standard stairs in those situations.
    Third, the Agency believes the performance-based language in the
final rule does a better job of targeting the areas where it is not
possible to use standard stairs and, thus, provides more protection for
workers than the existing and proposed rules. The final rule limits the
use of non-standard stairs to those situations in which it is not
possible to use standard stairs. For example, under the final rule,
employers must use standard stairs in special limited usage areas if it
is possible to install them.
    OSHA requested comment on proposed rule, including whether the
final rule also should identify additional or specific limited usage
areas where employers can use non-standard stairs (75 FR 28882). Two
stakeholders said OSHA should narrow the situations in which employers
may use non-standard stairs (Exs. 97; 159). For example, NFPA stated:

    [I]t appears that OSHA is proposing to allow other than Standard
Stairs to be used as long as the employer shows a Standard Stair
cannot be used. However, no criterion as to why a standard stair
could not be used is provided. Section 1910.25(a)(9) seems to allow
spiral stairs, ship stairs or alternating tread devices without any
limits. NFPA suggests OSHA establish a bracket of circumstances when
such devices can be used (Ex. 97).

    In particular, NFPA recommended that OSHA limit the circumstances
in which employers may use non-standard stairs to the following list,
which are the circumstances where NFPA 101 Life Safety Code allows the
use of non-standard stairs, such as alternating tread-type stairs:
     As a means to access unoccupied roof spaces;
     As a second means of egress from storage elevators;
     As a means of egress from towers and elevated platforms
around machinery or similar spaces, and occupied by no more than three
persons at the same time; and
     As a secondary means of egress from boiler rooms or
similar spaces, and occupied by no more than three persons at the same
time (NFPA 101-2009, Section <IP_ADDRESS>).
    NFPA added that incorporating the NFPA 101-2009 list would ``close
the gap created by the proposed language and greatly limit the
circumstances by which `non-standard' stairs are acceptable for use''
(Ex. 97).
    Similarly, Jacqueline Nowell, of the United Food and Commercial
Workers Union (UFCW), recommended that OSHA adopt a definition of
special limited usage that is narrower than the IBC-2009 definition:

    The Agency refers to the ICC Building Code definition [of
special limited usage] as ``a space not more than 250 square feet
(23m\2\) in area and serving not more than five occupants.'' Work
platforms in many packaging houses would meet this definition of
``special limited usage.'' By allowing the use of spiral stairs or
other non-standard stairs, OSHA would be introducing a new and
unnecessary hazard to the workers who must climb up and down from
these platforms multiple times a day, wearing heavy and bulky layers
of personal protective equipment. I urge OSHA to develop a more
restricted definition of ``special limited usage'' in order to
prevent falls and other injuries to these workers (Ex. 159).

    On the other hand, Southern Company (Ex. 192) said the definition
of ``special limited usage'' in IBC-2009 (i.e., ``a space not more than
250 square feet'') was too restrictive and urged OSHA to adopt a more
flexible approach (Ex. 192). They pointed out that mezzanine storage
space generally is a special limited use area, even though in many
cases the space may exceed 250 square feet (Ex. 192). They recommended
that OSHA follow the approach in STD 01-01-011 and its letters of
interpretation and allow the use of non-standard stairs when space
limitations make the use of standard stairs infeasible, regardless of
whether the space is greater than 250 square feet (Ex. 192) (See Letter
to Edward Feege (August 20, 1982) and Erin Flory (February 10, 2006)
\27\).
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    \27\ Available from OSHA's Web site at: https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=25301.
---------------------------------------------------------------------------

    OSHA believes the performance-based language in final paragraph
(b)(8) addresses many of the concerns the stakeholders raised. The
language in the final rule provides the increased flexibility that
Southern Company supports. At the same time, the final rule limits the
use of non-standard stairs to those circumstances where, based on
specific case-by-case evaluations and demonstrations, it is not
possible to use standard stairs. Thus, for example, if it is possible
to use standard stairs in a space that is less than 250 square feet,
the employer is not permitted to use non-standard stairs under the
final rule. In conclusion, OSHA adopts final paragraph (b)(8) as
discussed.
    Final paragraph (b)(9), which is a new provision, requires
employers to ensure that non-standard stairs are installed, used, and
maintained in accordance with manufacturer's instructions. Since 1982,
OSHA Instruction STD 01-01-011 has applied this requirement to
alternating tread-type stairs. Although final Sec.  1910.22(d) already
requires that employers inspect and maintain walking-working surfaces
in a safe condition, OSHA believes that specifically requiring that
non-standard stairs comply with the instructions or provisions the
manufacturer has issued for the installation, use, and maintenance is
critical to ensure that unique aspects of these stairs are identified
and addressed. OSHA also believes this requirement is necessary to
minimize potential risks inherent in spiral, ship, and alternating
tread-type stairs (e.g., reduced tread depth, increased stair angle,
improper climbing techniques) and to ensure those stairs are safe for
workers to use. OSHA notes that final paragraph (b)(9), like final
Sec.  1910.22(d), applies to existing spiral, ship, and alternating
tread-type stairs as well as non-standard stairs installed after the
final rule is effective.
    Finally, the Agency notes the requirements for spiral, ship, and
alternating tread-type stairs in final paragraphs (b)(8) and (9) that
employers must follow are in addition to the other general requirements
in final paragraph (b) and specific requirements in final paragraphs
(d), (e), and (f), which also apply to non-standard stairs.
Paragraph (c)--Standard Stairs
    Paragraph (c) of the final rule, like proposed paragraph (b),
establishes specific requirements for standard stairs that apply in
addition to the general requirements in final paragraph (b). OSHA
believes these specific requirements are the minimum criteria necessary
to ensure workers can negotiate standard stairs safely. The
requirements in final paragraph (c) generally are consistent with the
A1264.1-2007 standard and most of the requirements are in the existing
rule.
    Final paragraph (c)(1), like proposed paragraph (b)(1) and existing
Sec.  1910.24(e), requires employers to install standard stairs at
angles between 30 and 50 degrees from the horizontal. The final rule is
consistent with

A1264.1-2007, which permits employers to install standard stairways at
angles between 30 and 70 degrees from the horizontal, depending on the
type of stairs. The final standard includes a diagram explaining that
the slope for standard stairs is 30 to 50 degrees (see Figure D-10).
OSHA received no comments on the proposal and adopted the provision as
proposed.
    Final paragraphs (c)(2) and (3), like proposed paragraphs (b)(2)
and (3), require that employers ensure standard stairs have a maximum
riser height and minimum tread depth of 9.5 inches.\28\ The final rule
also includes an exception (final paragraph (c)(5)) on riser heights
and tread depths for standard stairs installed prior to the effective
date of the final rule, which is January 17, 2017. The exception
specifies that employers will be in compliance with the riser height/
tread depth requirements if they meet the dimensions specified in the
note to final Sec.  1910.25(c)(2) and (3), or if they use a combination
that achieves the required angle range of 30 to 50 degrees.
---------------------------------------------------------------------------

    \28\ Riser height is a vertical distance that is measured from
the tread (horizontal surface) of one step to the top of the leading
edge of the tread above it. Tread depth is a horizontal distance
that is measured from the leading edge of a tread to the point where
that tread meets the riser (See Sec.  1910.25, Figure D-8). This
method of measuring riser height and tread depth is consistent with
NFPA 101-2009 (Section <IP_ADDRESS>.5) and IBC (Section 1009.7.2).
---------------------------------------------------------------------------

    The existing rule (Sec.  1910.24(e)) does not specify a maximum
riser height or minimum tread depth for fixed stairs. Instead, it
requires that fixed stairs be installed at an angle of 30 to 50 degrees
from horizontal and allows employers to use any combination of uniform
riser and tread dimensions that achieves a stairway angle within the
required range. To assist employers, the existing rule (Sec.
1910.24(e), Table D-1) provides examples of riser height and tread
depth combinations that will achieve the required angle range. The
existing rule also specifies that employers may use riser and tread
combinations other than those listed in Table D-1, provided they
achieve a stairway angle that is within the required slope of 30 to 50
degrees.
    Like the final rule, A1264.1-2007 (Section 6.5) requires a 9.5-inch
maximum riser height and minimum tread depth. And like the existing
rule, A1264.1-2007 also allows employers to use any combination of
riser and tread dimensions that achieve a stair angle within the
permissible range. OSHA notes that A1264.1-2007 (Section E6.4)
specifies that the permissible angle range for ``typical fixed stair''
is 30 to 50 degrees, which is consistent with the existing and final
rules.
    OSHA believes that the riser height and tread depth requirements in
final paragraphs (c)(2) and (3), respectively, are simpler, clearer,
and easier to understand and follow than the existing rule. The final
rule also makes it easier for employers to achieve the required stair
angle range of 30 to 50 degrees in final paragraph (c)(1).
    OSHA received several comments on the proposed riser height and
tread depth requirements. For example, Ellis Fall Safety Solutions (Ex.
155) advocated that OSHA follow the maximum riser heights and minimum
tread depths of 7 and 11 inches, respectively, in IBC-2009, stating,
``If other locations in commerce are 7/11 why should we not find that
at work too? Also it is less tiring for workers to climb a 7/11 stair .
. . . OSHA should not be different than the IBC Building Code in this
instance'' (Ex. 155).
    To reduce employer burdens, Ellis also suggested that the final
rule include a provision grandfathering in the riser and tread
dimensions of existing stairways until employers do ``major
renovation'' of the stairs (Ex. 155). Southern Company agreed that OSHA
should grandfather in existing stairways that have a tread depth of
less than 9.5 inches, ``[W]e have not seen data that an existing
stairway with an 8 inch tread depth produces an increase in the fall
exposure that would justify replacing these stairs. Absent data . . .
we feel these stairs should be grandfathered'' (Ex. 192).
    NFPA, on the other hand, said there was ``no technical
justification'' for allowing a tread depth of less than 9.5 inches,
especially since it was more lenient than the 11-inch tread depth
requirement in new IBC codes (Ex. 97).
    OSHA agrees with NFPA that the 9.5-inch minimum tread requirement
in the proposed, final, and A1264.1-2007 standards provides stepping
space that is adequate to protect workers from falling. Although
A1264.1-2007 (Section 6.5) requires a 9.5 maximum riser height and
minimum tread depth, an explanatory note also suggests that employers
consider the riser and tread requirements in IBC codes. OSHA notes that
employers who have or install standard stairs with an 11-inch tread
depth, which IBC-2009 requires, are in compliance with the final rule.
Moreover, as mentioned above, OSHA grandfathers in the riser heights
and tread depths of existing stairs even if they are less than 9.5
inches, which addresses the concerns of Southern Company.
    OSHA removed from final paragraph (c)(3) the proposed exception
from the minimum tread-depth requirement for stairs with open risers.
OSHA adopted the proposed exception from the 9.5-inch tread-depth
requirement for open risers from A1264.1-2007. A note to that standard
explained: ``Open risers are needed on certain narrow tread and steep
angled stair systems and exterior structures'' (Section E6.13.).
    NFPA opposed the proposed exception, saying that allowing a tread
depth of less than 9.5 inches for open risers is problematic in two
ways:

    (1) Where open risers are present, not only does the specific
9.5-inch not apply, but no minimum tread depth is specified. The
tread depth could be as little as 3-4 inches. (2) Stairs are used
for travel in the downward direction at least as much as they are
used for travel in the upward direction. An open riser might help to
provide some extra ``effective'' tread depth for persons using the
stair for upward travel. . . . [However,] [a]n open riser does not
create greater effective tread depth for persons using the stair for
downward travel (Ex. 97).

In addition, NFPA maintained that there is no technical justification
for permitting a tread depth of less than 9.5 inches when the riser is
open, stating, ``The 9.5-inch minimum tread depth specified [in
paragraph (c)(3)] is already lenient as compared to the minimum 11-inch
tread depth required in new construction model codes. The exemption for
open risers should be deleted'' (Ex. 97). OSHA agrees with NFPA and,
therefore, removed the proposed exception for standard stairways with
open risers from the final rule.
    Final paragraph (c)(4), like proposed paragraph (b)(4), requires
that employers ensure standard stairs have a minimum width of 22 inches
between vertical barriers. Examples of vertical barriers include stair
rails, guardrails, and walls. The added language makes the final
provision more protective than the existing rule (Sec.  1910.24(d)),
which also requires a tread width of 22 inches but does not specify how
to measure the width. The additional language makes the final rule
consistent with A1264.1-2007, which requires a minimum clear width of
22 inches. OSHA did not receive any comments on the proposed provisions
and adopts the provision as proposed.
    The requirements for non-standard stairs in final paragraphs (d)
(spiral stairs), (e) (ship stairs), and (f) (alternating tread-type
stairs) parallel most of the provisions established for standard stairs
in paragraph (c). Like the requirements for standard stairs, the
requirements for spiral, ship, and alternating tread-type stairs
represent the minimum requirements OSHA believes are necessary to
ensure that

employees are able to move safely from one walking-working surface to
another. OSHA adopted the requirements for non-standard stairs from
A1264.1-2007, NFPA 101-2012, and IBC-2012.
Paragraph (d)--Spiral Stairs
    Final paragraph (d), like proposed paragraph (c), establishes
specific requirements for spiral stairs. As mentioned earlier, these
requirements apply in addition to the general requirements in paragraph
(a). OSHA adopted most of the requirements in final paragraph (d) from
NFPA 101-2012. OSHA believes that the vast majority of spiral stairs
currently in use already meet the requirements in final paragraph (d)
because these spiral stairs conform to the current industry practice
expressed in this NFPA standard. Therefore, OSHA believes employers
will not have difficulty complying with the final rule.
    Final paragraph (d)(1), like paragraph (c)(1) of the proposed rule,
requires that employers ensure spiral stairs have a minimum clear width
of 26 inches. The ``clear'' width requirement in final paragraph (d)(1)
is similar to the approach in final paragraph (c)(4) and A1264.1-2007
(Section 6.3). That is, the width is measured from the vertical barrier
on the outside of the stairway to the inner pole onto which the treads
are attached. Spiral stairs need a greater width than standard stairs
because only the outside portion of the stairs can be stepped on since
the inner part of treads are too short in depth. OSHA did not receive
any comments on the proposed provision and adopts the provision as
proposed.
    Final paragraph (d)(2), like proposed paragraph (c)(2) and final
paragraph (c)(3), requires that employers ensure that spiral stairs
have risers with a maximum height of 9.5 inches. OSHA did not receive
any comments on the proposed provision, and the final rule adopts the
provision as proposed.
    Final paragraph (d)(3) requires that employers ensure spiral stairs
have a minimum headroom above the spiral stair treads of at least 6
feet, 6 inches. The final rule also requires that employers measure the
vertical clearance from the leading edge of the tread. This requirement
means that, at any and every point along the leading edge, the minimum
headroom must be at least 6 feet, 6 inches. The proposed rule
(paragraph (c)(3)) specifies that same minimum headroom, but proposed
to measure it at the center of the leading edge of the tread. OSHA
believes it is necessary to revise the method for measuring the
vertical clearance to prevent injury to workers when using spiral
stairs. The minimum headroom the final rule requires for spiral stairs
is two inches less than the headroom final paragraph (b)(2) requires
for all other stairways. Because the required headroom is less, OSHA
believes it is important that employers measure the required minimum
headroom at all points along the leading edge. OSHA did not receive any
comments on the provision and adopts the proposed provision with the
change discussed.
    To ensure that workers are able to maintain safe footing while
using spiral stairs, final paragraph (d)(4), like proposed paragraph
(c)(4), requires that employers ensure spiral stairs have a minimum
tread depth of 7.5 inches. Because the tread depth on a spiral stair is
not the same across the width of the tread, the final rule also
requires that employers measure the minimum tread depth at a point 12
inches from the narrower edge. This requirement ensures that workers
will have adequate space at the point on the tread where they are most
likely to step.
    Although the minimum tread depth final paragraph (d)(4) requires is
less than that for standard stairs, OSHA has several reasons for
concluding that the minimum 7.5-inch tread depth is adequate to provide
safe footing for workers. First, spiral stairs usually have open risers
that provide additional space for the foot. Second, employers use
spiral stairs where space restrictions make the use of standard stairs
infeasible. In restricted-space situations, there may be insufficient
room for stairways with 9.5-inch tread depths. Third, final paragraph
(d)(4) is consistent with NFPA 101-2012. OSHA did not receive any
comments on the proposal and adopts the provision as proposed.
    Final paragraph (d)(5), like proposed paragraph (c)(5), requires
that employers ensure spiral stairs have a uniform tread size. As OSHA
mentioned in the discussion of paragraph (b)(3), this requirement is
necessary because, in the Agency's experience, even small variations in
tread size and shape may cause trips and falls. OSHA did not receive
any comments on the proposed rule and adopts it as proposed.
Paragraph (e)--Ship Stairs
    Final paragraph (e), like proposed paragraph (d), provides specific
requirements employers must follow in situations where they may use a
type of stair commonly referred to as a ``ship stair'' or ``ship
ladder.'' Employers often use ship stairs as a means to bypass large
equipment, machinery, or barriers in tight spaces. OSHA drew some of
the provisions in final paragraph (e) from the A1264.1-2007 standard.
    The requirements in final paragraph (e) apply in addition to the
general requirements specified in paragraph (a) above. In addition,
OSHA is reorganizing some of the provisions in final paragraph (e) to
make the paragraph easier to follow and understand. For example, OSHA
is grouping the riser requirements into one provision (final paragraph
(e)(2)).
    OSHA notes that the requirements in final paragraph (e) apply only
to ship stairs used in general industry. Some commenters raised
concerns about whether OSHA was applying the requirements in paragraph
(e) to ship stairs used on vessels. For example, Northrop Grumman
Shipbuilding (NGS) said:

    OSHA has included a definition (Sec.  1910.21(b)) and design
requirements for ship stairs. . . . [W]e wish to clarify that
despite the inclusion of the term ``ship stairs'' in the standard,
OSHA is not attempting to extend application of the design criteria
for ladders, stairs or other walking-working surfaces to vessels,
which we believe are under the regulatory authority of the United
States Coast Guard (Ex. 180).

Mercer ORC Networks raised similar concerns:

    Mercer believes that OSHA intends to apply this definition to a
particular stair or ladder configuration wherever it is found,
whether on a ship or in a land-based facility. However, if one reads
the definition literally (which should be possible with