

Thursday, November 3, 2011

Do you really need to put all that equipment in my house to dry it?

One of the most frequent questions asked, or thought about during water damage restoration work is; do you really need to bring all that equipment in my house?"

What is the process that goes into determining if we have adequate amount, or too much equipment.  There are formulas we follow, calculations we calculate, and measurements to measure.  You should never be given an answer along the lines of "because that is how much we have on the truck", or "because we always use this much equipment."  Be suspect if you do not see the technicians working hard to figure the actual need of equipment.  There are tools, and meters, and gauges available to professionals to determine the equipment requirements for each job.  Just as two people are not the same, each water damage we go into has its own wants and needs.

How do we do it.  How does Damage Control determine the equipment load needed to dry each job to a pre-loss condition, or back to dry like it never happened conditioned.

One of my favorite formulas used to calculate the dehumidification requirements in a water damaged building is fun.
Step 1.  Simply figure how much air space is in the room or building and figure how much moisture can be put into that airspace.  Cubic feet is calculated Length x Width x Height.
Step 2.  Determine the class of water loss, classes1-4.  This is in reference to the type of water loss, location of water source, how much water is effecting the structure, and the type of building materials affected.
class 1.  water losses that affect only a part of the room, with a minimum amount of moisture
class 2.  water losses that affect the entire room of carpeting with water wicking up the walls to 24".
class 3.  water came from overhead.  Walls, ceilings, insulation, carpet and padding, virtually the entire area is saturated.
class 4.  These involve materials with low permeance.  Hardwoods, brick, plaster, concrete, stone, etc..
Step 3.  Determine the type of dehumidifiers being used and its capacity of water removal.  Each machine has different capacities and abilities.  We are looking at the number of pints of water removal per day here.  Once we have all the info needed we can then determine the equipment needs for dehumidification in that area.
Example: 1500 sf. class 2 water loss @ 12,000 cf. / 50 pints (dehu) = 240 pints of dehumidification needed.
As explained earlier each dehumidifier is different in it capacity to handle a job.  Most of our units process 120 - 130 pints per day.  So on this job in the example above, we would use 2 dehu's on this 1500 sf water loss.

Dehumidifiers are rated at pints per day.  We measure their ability to remove moisture from the air in grains.  To make sure the equipment is working properly, and still needed on that job site, we take readings each time we check on that job.  We keep track of atmosphere conditions and wall readings.  The atmospheric readings are called psychrometric readings.  With these readings we determine grains of moisture per pound of air.  It is this way we keep track of the specific moisture and compare that with the moisture content in the materials we are trying to dry.  Simply put, if the air is dry, the structure will be able to dry.


How do we get that dry air to the wet surface?  Thank goodness there are not confusing scientific formulas for  this piece of equipment.  Each airmover is designed to push airflow.  I call it energy.  Each piece is designed differently, but measured in cfm (cubic feet per minute).  In general, an airmover should be placed with in 12 feet of another to maximize airflow.  If there are obstructions blocking the airflow, equipment can be placed accordingly to have adequate airflow.  If doors are in the way, we remove them.  Airmovers should be placed  at a 45 degree angle to push enough air to the hard to reach areas and increase airflow from the center of the room to allow carpet and padding to dry.
To directly answer the determining factor used in airmover placement; it depends on what is in the room we are drying.  If empty, the room can dry faster..!!

I hope this makes sense, and allows to clear some confusion as to why we do what we do.  The dehumidifiers are easy to calculate on paper.  The airmovers are essential to push dry air, energy, across the wet surfaces.  The 2 pieces of equipment work hand in hand to accomplish one common goal.  That goal is our goal:  Keep the Home Owner happy, and warm and dry.  Dry the structure as rapidly as possible and minimize the damages or need for repairs.

Thanks for taking the time to read.  We are standing by ready to serve, Call today @ 406-274-4168

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