diving cylinder diving cylinder tank diving tank gas cylinder store transport high pressure breathing gas required set surface supplied diving gas emergency gas supply surface supplied diving cylinders provide gas demand valve diving breathing loop diving diving cylinders usually manufactured aluminium steel normally fitted common types cylinder valve filling connection accessories cylinder bands protective nets boots carrying handles provided configurations harness carry cylinder cylinders diving depending application cylinders typically internal volume known water capacity litres maximum working pressure rating bars psi cylinders available smaller sizes litres breathing instead purposes inflation surface marker divers dive single cylinder pair similar cylinders main cylinder smaller pony cylinder usually carried specialised diving cylinders needed cylinders mounted waist mount cylinder carries equivalent volume free gas greater water capacity gas compressed times atmospheric pressure selection appropriate set diving cylinders diving operation based gas required safely complete dive diving cylinders commonly filled air main components air cause problems underwater higher pressure divers choose breathe cylinders filled gases air cylinder containing needs labelled indicate contents safety reasons jurisdictions regulations govern filling recording contents diving cylinders periodic inspection testing cylinders ensure safety operators filling stations diving cylinders considered dangerous goods commercial transportation regional international rules apply terminology term diving cylinder tends gas equipment engineers manufacturers support professionals divers speaking british english tank diving tank colloquially non professionals native speakers american english term oxygen tank commonly non divers referring diving cylinders cylinders typically contain compressed atmospheric breathing air oxygen enriched air mix rarely contain pure oxygen diving shallow stops technical diving water oxygen therapy breathing pure oxygen depths greater metres equivalent partial pressure oxygen bars result oxygen highly dangerous condition trigger lead drowning diving cylinders referred bottles usually diving cylinders called trademark derived lung equipment lung company properly applied open circuit set open circuit diving diving cylinders specified application cylinders stage cylinders cylinders cylinders pony cylinders suit inflation cylinders etc parts cylinder functional diving cylinder consists pressure vessel cylinder valve pressure vessel pressure vessel seamless cylinder normally cold aluminium forged steel wound composite cylinders fire fighting breathing apparatus oxygen aid equipment low weight rarely diving high positive occasionally dive site critical cave diving composite cylinders certified underwater applications manufactured accordance requirements underwater use marked aluminium cylinders especially common cylinder provided tropical dive resorts aluminium aluminium cylinder design internal volume cubic feet rated hold nominal volume cubic feet atmospheric pressure gas rated working pressure pounds square inch bar aluminium cylinders divers carry cylinders technical diving water warm dive suit provide greater aluminium cylinders reduces extra need achieve neutral preferred carried cylinders near neutral allows hang comfortably sides body disturbing trim handed stage dropped minimal effect aluminium cylinders flat allowing stand upright level surface manufactured bottoms aluminium diving cylinders subject sustained load cracking cylinders manufactured periodically current tested according national legislation manufacturer recommendations superseded new manufacture old cylinders service manufacture aluminium cylinders usually manufactured cold aluminium process presses walls base edge cylinder walls followed press forming shoulder neck final structural process neck outer surface boring cutting neck threads ring groove cylinder heat treated tested stamped required permanent markings aluminium diving cylinders commonly flat bases allows stand upright horizontal surfaces relatively thick allow rough treatment considerable wear makes heavier need strength extra weight base helps centre gravity low gives better balance water reduces excess steel cylinders cold water diving wearing highly dive suit large excess steel cylinders aluminium cylinders lower mass aluminium cylinders gas capacity considerably higher material strength use steel cylinders result lighter cylinder ballast required gas capacity way saving overall dry weight carried steel cylinders susceptible aluminium external particularly coated barrier resist damage difficult monitor external repair paint damaged steel cylinders maintained long service life longer aluminium cylinders susceptible fatigue damage filled safe working pressure limits steel cylinders manufactured convex concave bottoms profile allows stand upright horizontal surface standard shape industrial cylinders cylinders emergency gas supply diving bells shape commonly water capacity litres bottoms larger volume cylinder mass standard cylinders litres water capacity concave cylinders marketed manufacture steel dive cylinder manufacture authorised manufacturing standard example standard dot requires use open basic oxygen electric steel uniform quality approved include carbon intermediate specified constituents including carbon steel cylinders manufactured steel plate discs cold drawn cylindrical cup form stages generally base intended market stand forming base walls cylinder trimmed length heated hot spun form shoulder close neck process material shoulder cylinder heat treated provide best strength cylinders provide neck thread ring seat applicable cleaned shot inside remove mill scale inspection testing stamped required permanent markings followed external coating barrier paint hot dip cylinder neck neck cylinder internally fit cylinder valve standards neck threads include thread right hand thread standard form pitch threads inch threads pitch diameter thread cylinder millimetres connections sealed thread tape newton metres lbf steel cylinders lbf aluminium cylinders parallel threads standards parallel thread sealed ring lbf steel lbf aluminium cylinders parallel thread sealed ring lbf steel cylinders lbf aluminium cylinders parallel thread thread form pitch diameter millimetres pitch threads inch parallel thread sealed ring lbf aluminium cylinders thread form pitch diameter pitch threads inch threads sealed ring lbf aluminium cylinders similar having pitch pitch diameter differs compatible thread forms different parallel thread sealed ring neck thread seals step cylinder neck valve shoulder cylinder carries stamp markings providing required information cylinder cylinder valve purpose cylinder valve pillar valve control gas flow pressure vessel provide connection filling cylinder usually brass finished protective decorative layer plating metal plastic dip tube valve valve extends cylinder reduce risk liquid cylinder getting gas passages cylinder inverted blocking dip tubes plain opening integral filter cylinder classified basic aspects cylinder thread specification connection pressure rating distinguishing features cylinder thread variations cylinder threads basic configurations thread parallel thread thread specifications detailed previous section valve thread specification exactly match neck thread specification cylinder matched neck threads fail pressure fatal consequences hit flying valve cylinder connection rubber ring forms seal metal pillar valve metal diving rings cylinders storing oxygen rich gas reduce risk fire basic types cylinder valve connection general use cylinders containing air clamp connection surrounds valve pillar presses output ring pillar valve input seat connection officially described connection hand impossible remove later tools seal created ring surfaces valve valve opened cylinder pressure expands ring outer surface ring groove valve insufficient force allow pressure ring valve faces resulting leak type connection simple cheap widely worldwide maximum pressure rating bar weakest seal ring protected din screw thread screws cylinder valve trapping ring sealing face valve ring groove reliable ring protected countries use din fittings widely cylinders din fittings traveling abroad din system need connecting din rented cylinder connecting clamp filler din cylinder valve cylinder cylinders containing gases air new european norm introduced new type valve similar existing bar bar din metric fitting cylinder intended breathing gas oxygen content normally found natural air earth atmosphere august required european_union diving equipment pure oxygen idea new standard prevent rich mixture filled cylinder oxygen clean use new system remains human procedural care ensure cylinder new valve remains oxygen clean exactly previous system worked male thread cylinder valve supplied semi closed circuit recreational use supplied compatible connection pressure rating rated bar appear mechanical design detail preventing connection fittings older fit popular bar combination din cylinder valve narrow din produced bar bar pressure ratings number threads detail configuration connections designed prevent incompatible combinations filler attachment attachment cylinder valve bar din thread outlet connector din technically specified cylinders bar test pressure bar din thread outlet connector din similar thread din fitting rated bar working pressures technically specified cylinders bar test pressure bar pressures common european diving cave diving available allow connection din cylinder clamp connect din cylinder plug block plug rated bar designed accept block generally rated bar bar din valve distinguishing features plain commonly cylinder valve type single outlet plain valve known valve allows connection single reserve function simply opens allow gas flow closes shut configurations options din clamp connection vertical transverse arrangements valve operated turning usually rubber plastic comfortable grip turns required fully open din clamp use insert opening cylinder outlets valve allowing connected cylinder common failure mode happen water valve closed cylinder connected valve difference valve valve valve body splits posts roughly vertical axis looking like valve usually assembled valve designed system additional valve post connected valve posts parallel vertical looks bit like known appearance reserve reserve valve 1970s pressure came common use diving cylinders mechanical reserve mechanism indicate cylinder nearly gas supply automatically cut spring loaded valve gas pressure reached reserve pressure release reserve pulled rod ran cylinder activated open bypass valve finish dive reserve typically pounds square inch bar consumed occasion divers inadvertently trigger mechanism gear performing movement underwater realizing reserve accessed find air depth warning whatsoever valve got item equipment manufacturer standard non reserve valve time item referred valve occasionally professional divers zero visibility pressure gauge read recreational diving industry largely discontinued support sales valve navy national allow recommend use alternative cylinder alternative pressure gauge generally available recreational dive shops available manufacturers significantly expensive manufacturer common 1950s 1970s valve equipped restriction caused breathing difficult cylinder neared exhaustion allow restricted breathing began ascend ambient water pressure providing larger pressure differential particularly popular necessary descend necessary cave wreck diving breathing progressively difficult went deeper eventually impossible ascent low ambient pressure handed cylinder valve models line cylinder axis handed standard right mounted handed pair right left cases valve opened turning closed turning clockwise convention purposes left hand divers disk national standards require cylinder valve includes disk pressure relief device release gas cylinder fails event disk dive entire contents cylinder lost short time risk happening correctly rated disc good condition correctly filled cylinder low accessories additional components convenience protection functions directly required function pressure vessel cylinder tube connects cylinders contents supplied commonly configurations oldest type tube connector end attached cylinder valve outlet outlet connection middle attached variation pattern includes reserve valve outlet connector cylinders isolated closed attached disconnected cylinders recently available connect cylinders cylinder valve leaving outlet connection cylinder valve available connection means connection broken cylinders valve interior cylinder apparent allows connected cylinder isolated internal pressure independently allows cylinder isolated allowing cylinder access gas cylinders plain include isolation valve allows contents cylinders isolated allows contents cylinder isolated secured leak cylinder neck thread connection burst disk cylinder causes contents lost relatively uncommon system connection screws directly neck threads cylinders single valve release gas connector include reserve valve main valve cylinder system mainly historical interest valve cage known cage cage structure neck shoulder cylinder cylinders protect stages impact damage use rolling valve closed friction overhead valve cage steel designs cylinder bands cylinder bands usually steel clamp cylinders twin set cylinders independent usual use cylinder band near cylinder shoulders lower conventional distance inches cylinder boot cylinder boot hard rubber plastic cover fits base diving cylinder protect paint impact protect surface cylinder stands impact cylinder case round cylinders allow cylinder stand upright base boots flats plastic reduce tendency cylinder roll flat surface possible cases water trapped boot cylinder paint boot poor condition surface cylinder areas usually avoided fresh water use storing dry place added drag caused cylinder boot trivial comparison overall drag boot styles present slightly increased risk environment cylinder net cylinder net tubular net stretched cylinder tied function protect cylinders helps drain surface boot cylinder reduces problems boot size usually millimetres divers use boots nets easily bare cylinder constitute hazard environments caves interior occasionally materials protect cylinder cylinder handle cylinder handle fitted usually neck carry cylinder increase risk enclosed environment dust caps cover cylinder valve cylinder use prevent dust water materials help prevent ring type valve falling plug gas cylinder plug making difficult remove cylinder pressure rating thickness cylinder walls directly related working pressure affects characteristics cylinder low pressure cylinder high pressure cylinder similar size proportions length diameter working pressure cylinders technically high pressure gas containers industry nominal working pressure ratings common use low pressure psi bar standard psi bar high pressure psi bar aluminum cylinders usually standard working pressure pounds square inch bar compact aluminum range working pressure pounds square inch bar steel cylinders manufactured standards permitted exceed nominal working pressure indicated symbol extra pressure dependent cylinder passing appropriate higher standard periodical test parts world metric system usually refer cylinder pressure directly bar generally use high pressure refer bars psi working pressure cylinder connector bar popular working pressure cylinders steel aluminium test pressure test pressure specified manufacturing standard usually working pressure usa working pressure developed pressure cylinder working pressure specified reference temperature usually cylinders specified maximum safe working temperature actual pressure cylinder vary temperature described gas laws acceptable terms standards provided developed pressure corrected reference temperature exceed specified working pressure stamped cylinder allows cylinders safely legally filled pressure higher specified working pressure filling temperature greater reference temperature provided filling pressure exceed developed pressure temperature cylinders filled according provision correct working pressure cooled reference temperature pressure monitoring internal pressure diving cylinder measured stages use checked filling monitored filling checked filling completed pressure gauge filling equipment pressure generally monitored firstly check contents use use ensure left times allow safe completion dive dive purposes record keeping personal consumption rate calculation pressure monitored testing ensure test correct pressure diving cylinders dedicated pressure gauge standard feature diving requirement filling facilities widespread standards pressure measurement diving gas usa places pressure measured pounds square inch psi rest world uses bar metric units kpa particularly actually underwater cylinder capacity commonly conventions describing capacity diving cylinder based internal volume cylinder based nominal volume gas stored internal volume internal volume commonly quoted countries metric system information required stamped cylinder shoulder measured easily filling cylinder fresh water resulted term water capacity abbreviated marked cylinder shoulder expressed volume litres mass water fresh water density close kilogram numerical values similar standard sizes internal volume representative examples larger range line manufacturers consulted applications typical exclusive litres available steel litres available steel litres available steel bar single twins gas litres available steel single twins gas litres available steel bar single twins gas litres available steel bar aluminium bar single twins gas litres available steel bar aluminium bar single twins gas litres available aluminium bar single twins gas litres available aluminium bar single twins gas litres available steel bar single twins gas litres available aluminium bar gas litres available steel bar semi closed litres available steel bar aluminium bar gas singles twins cylinders popular size litres available steel bar gas singles twins cylinders popular size litres available steel bar litres available steel bar litres available steel bar pony cylinders litres available steel bar pony cylinders litres available steel bar pony cylinders suit inflation litres available steel bar suit inflation litres available steel aluminium bar surface marker inflation nominal volume gas stored nominal volume gas stored commonly quoted cylinder capacity usa measure volume gas released cylinder atmospheric pressure terms capacity include free gas volume free gas equivalent depends internal volume working pressure cylinder working pressure higher cylinder store gas volume nominal working pressure necessarily actual working pressure steel cylinders manufactured standards permitted exceed nominal working pressure indicated symbol extra pressure dependent cylinder passing appropriate periodical test necessarily valid cylinders exported countries differing standards nominal gas content cylinders based higher pressure example common aluminum cylinder aluminum cylinder nominal free gas capacity cubic feet pounds square inch bar internal volume litres standard sizes volume gas stored large high pressure pounds square inch bar cylinder heavy pounds probably cylinder resorts parts world gas popular cylinder gas mount cylinder fresh water nearly neutral cylinders internal volume approximately litres working pressure pounds square inch bar twins mount application needs ballast weights steel cylinders equivalent capacity aluminium high pressure equivalent water capacity working pressure pounds square inch bar popular cylinder mount mount gas moderate depths small diameter nearly neutral makes relatively mounting style internal volume approximately litres working pressure pounds square inch bar pounds square inch bar steel smaller lighter lower capacity suitable smaller divers shorter steel pounds square inch bar pounds square inch bar compact lighter negatively reduces ballast weight required steel cylinders provide larger amounts gas technical diving applications configurations diving cylinders divers carry cylinder depending requirements dive diving takes place low risk areas safely free ascent buddy available provide alternative air supply emergency recreational divers usually carry cylinder diving risks higher example visibility low recreational divers deeper diving particularly diving overhead divers routinely carry gas source diving cylinders serve different purposes cylinders primary breathing source intended dive smaller cylinder carried addition larger cylinder called pony bottle cylinder purely independent safety reserve called bottle emergency gas supply pony bottle commonly bottle depend time required surface divers technical diving carry different gases separate cylinder phase dive travel gas descent ascent typically air oxygen content travel gas needed gas unsafe breathe shallow water gas depth typically based gas low oxygen gas stops generally mixes high oxygen content pure oxygen accelerate stage cylinder holding reserve travel gas usually carried harness wing left distance line picked use return stage dropped commonly divers use aluminium stage cylinders particularly fresh water nearly water removed underwater effect overall safety divers carry additional independent cylinder air primary breathing gas supply fail common recreational diving controlled emergency swimming ascent safe extra equipment needed extra cylinder known bail cylinder carried ways size hold gas safely surface open circuit open circuit divers options combined cylinder system single cylinder consists single large cylinder usually mounted stage usually second stage configuration simple cheap single breathing gas supply case failure cylinder stage fails totally air faces life threatening emergency recreational training agencies train divers rely buddy assist situation skill gas sharing trained entry level courses equipment configuration common entry level divers sport diving recommended training agencies dive stops needed overhead environment wreck diving cave diving ice diving provides functional single cylinder dual consists single large mounted cylinder stage second stage system diving cold water makes risk freezing high functional required common continental europe especially germany advantage failure solved underwater bring dive controlled conclusion buddy breathing gas sharing hard reach reliance dive buddy help close valve free flowing quickly main cylinder plus small independent cylinder configuration uses larger mounted main cylinder independent smaller cylinder called pony cylinder independent systems total breathing system heavier expensive buy maintain pony typically cylinder capacity determines depth dive duration provides protection fixed main cylinder harness chest carried cylinder provide accepted reliable emergency gas supply require trained use type small independent air source hand held cylinder filled litres free air diving directly attached spare air source provides gas depth suitable shallow water independent twin sets independent doubles consists independent cylinders pressure gauge system heavier expensive buy maintain expensive fill single cylinder set swap demand dive preserve sufficient reserve gas cylinder cylinder fail end having inadequate reserve independent twin sets work air integrated computers usually monitor cylinder complexity switching periodically ensure cylinders evenly offset entirely separate breathing gas supplies cylinders mounted twin set alternatively carried configuration penetration caves requires cylinder easy reach plain twin sets doubles single consist mounted cylinders pillar connected attached makes relatively simple cheap means redundant functionality breathing system double gas supply arrangement fairly common early days low pressure cylinders provide larger air supply possible available single cylinders use large capacity sets deep commercial diving isolation twin sets doubles consist mounted cylinders pillar connected valve closed pillar event problem cylinder close valve preserve gas cylinder failed advantages configuration include larger gas supply single cylinder automatic balancing gas supply cylinders requirement constantly change underwater dive failure situations close valve failed cylinder retain access remaining gas tanks potential point failure danger losing gas cylinders isolation valve closed problem occurs configuration cylinders technical diving cylinders configuration independent cylinders technical diving independent cylinders carried harness purpose carry stage travel gas mounted cylinder carry gas stage cylinders carry gas extend time travel gas reach depth gas safely surface gas gas intended accelerate elimination gases gas emergency supply intended surface main gas supply lost mount cylinders cylinders harness sides carry gas carry mount cylinders conjunction mounted stage travel cylinders necessary skilled mount divers carry cylinders configuration developed access tight restrictions caves mounting primarily technical diving recreational diving single cylinder carried complete secondary second stage octopus configuration referred monkey diving diving cylinders diving roles source fresh gas stored cylinder cylinders lower gas consumption cylinders typically smaller equivalent open circuit use internal cylinders supplied board cylinders directly connected flexible usually carried oxygen oxygen cylinder semi closed circuit cylinder usually contains based gas closed circuit oxygen cylinder cylinder contains air based gas divers carry external system internal cylinder small safe use planned dive system independent breathing gas sources use fail open circuit open circuit sets number open circuit sets capacity breathing gases contain depend depth needs dive deep technical dive need bail gas gas dive usually capacity duration sets limits depth duration dive capacity closed circuit second containing independent diving cylinders gas supply bail possible uncommon long duration compelling bail relatively complex vulnerable damage require time start breathing easy use instantly available robust reliable open circuit equipment surface supplied emergency gas supply surface supplied divers usually required carry emergency gas supply sufficient allow return place safety main gas supply fails usual configuration mounted single cylinder supported safety harness stage connected low pressure block mounted helmet band mask harness supply lightweight face mask capacity single cylinder insufficient plain twins closed bell bounce set compact allow pass hatch bell sets limit size cylinders emergency gas supply diving bells diving bells required carry board supply breathing gas use cylinders mounted externally insufficient space inside fully immersed water bell operations considered diving cylinders uses compressed gas cylinders diving operations divers use gas cylinders water storage oxygen aid treatment diving disorders storage banks diving air stations gas blending surface supplied breathing gas gas supplies chambers systems similar cylinders purposes connected diving applications diving cylinders subject regulatory requirements cylinders underwater gas calculations necessary know approximate length time breathe given cylinder safe dive profile planned parts problem cylinder cylinder capacity store gas features cylinder determine gas carrying capacity cylinder gas pressure filled normally ranges bars psi actual value measured real situation cylinder internal volume normally ranges litres litres single cylinders quantity gas volume gas atmospheric pressure cylinder volume cylinder pressure atmospheric pressure parts world metric system calculation relatively simple atmospheric pressure bar cylinder bar hold litres air atmospheric pressure known free air capacity diving cylinder specified directly cubic feet free air nominal working pressure calculation internal volume working pressure relatively tedious imperial units diving resorts countries find aluminum cylinders manufacture internal capacity cubic feet filled working pressure psi bar taking atmospheric pressure psi gives cylinders described cubic foot cylinders common aluminum bar ideal gas law remains valid relationship pressure size cylinder gas contained cylinder linear higher pressures gas cylinder cylinder filled bar carry contain litres atmospheric pressure gas litres expected ideal gas law gas consumption main factors consider rate gas specified surface air consumption sac respiratory minute volume normal conditions litres minute min divers working hard times extreme high work rate breathing rates rise litres minute commercial diving gas planning purposes working breathing rate litres minute whilst figure litres minute controlled blood levels usually independent oxygen partial pressures change depth large range possible rates gas consumption results significant uncertainty long supply conservative approach required safety immediate access alternative breathing gas source possible divers expected monitor remaining gas pressure sufficiently aware available times dive ambient pressure depth dive determines ambient pressure surface bar psi sea level metres descends pressure increases bar psi goes deeper breathing gas delivered pressure equal ambient water pressure gas proportional pressure requires twice mass gas fill lungs metres surface times metres mass consumption breathing gas similarly affected time depth usually time depth range quantity gas consumed gas consumed surface air consumption time ambient pressure metric examples min bar consume min surface equivalent min bar minutes consume litres free air capacity bar cylinder imperial examples sac cubic feet minute consume surface equivalent sac minutes consume free air capacity cylinder keeping mind hard technical divers long deep require multiple cylinders commercial divers normally use surface supplied diving equipment carry emergency gas supply breathing gas endurance time breathe cylinder known air gas endurance absolute maximum breathing duration given depth calculated available air rate consumption ideal gas law available cylinder pressure cylinder volume rate air consumption surface ambient pressure written sac breathing time cylinder internal volume ambient pressure sac surface air consumption consistent system units ambient pressure surrounding water pressure given depth sum pressure air pressure surface calculated atmospheric pressure depth standard gravity water density consistent system units metric units formula depth pressure bar ambient pressure cylinder pressure quantity air represented practice breathing required balance ambient pressure water formula cracking pressure required open second stages pressure drop flow restrictions variable depending design adjustment flow rate depends breathing pattern gas use factors easily estimated calculated value breathing duration real value normal diving usage reserve reserve proportion cylinder pressure plan use case emergency reserve quarter cylinder pressure fixed pressure common examples bar psi formula modified usable breathing duration sac reserve example formula absolute maximum breathing time depth meters water average density typical rate litres minute dive cylinder litres bars breathe period minutes cylinder pressure falls low prevent open circuit systems happen suddenly normal breath abnormal breath breath fully drawn difficulty effect depends design internal volume cylinder circumstances remains air pressure cylinder unable breathe ambient pressure reduced ascent systems bit air cylinder available devices longer pressure open demand valve conditions reserve bar formula usable breathing time follows ambient pressure water pressure atmospheric pressure bar bar usable pressure fill pressure reserve pressure bar bar bar usable air usable pressure cylinder capacity bar litres bar litres rate consumption surface air consumption ambient pressure litres minute bar bar litres min usable breathing time litres litres min minutes dive time min reaching reserve bar reserves strongly recommended training organisations codes practice portion usable gas cylinder held aside safety reserve reserve designed provide gas longer planned stops provide time resolve underwater size reserve depends risks involved dive deep dive greater reserve shallow stop dive recreational diving example recommended plans surface reserve remaining cylinder psi bar initial capacity depending teaching training organisation recreational divers practicing limits normally direct ascent emergency technical direct ascent impossible overhead dangerous requirement stops divers plan larger margins safety simplest method uses rule thirds gas supply planned outward journey return journey safety reserve training agencies teach concept minimum gas rock gas management critical pressures allows acceptable reserve divers surface emergency point planned dive profile professional divers required legislation industry codes practice carry sufficient reserve gas enable reach place safety surface diving bell based planned dive profile reserve gas usually required carried independent emergency gas supply known cylinder set bottle usually applies professional divers surface supplied diving equipment weight gas consumed density air sea level approximately sized diving cylinders open circuit hold kilograms air air cylinder increases weight removed decrease external volume cylinder reduction internal pressure relatively small ignored practical purposes example cylinder filled bar dive bar litres free air mass gas dive depend mixture air assumed approximately kilograms loss weight gas taken cylinder makes cylinder problem unable remain end dive gas cylinder change gas usage mounted cylinders easily compensated carrying sufficient diving weights provide neutral cylinders end dive excess weight gas change diving cylinder dive problematic mounted cylinders actual point dive consideration cylinder separated reason cylinders stage dropped handed change compensated cylinders approximately neutral generally require compensation detached filling cylinders legal constraints filling cylinders vary jurisdiction south_africa cylinders filled commercial purposes person competent use filling equipment knows relevant sections applicable standards regulations written permission owner cylinder fill cylinder test suitable gas filled cylinder filled developed pressure temperature reached filled external inspection cylinder specified details cylinder fill recorded fill gas air analysis completed fill recorded filler signed customer pressure cylinder presented filling produce reasonably strong flow gas valve opened filler refuse fill cylinder acceptable reason given way filler check contaminated diving cylinders filled suitably filtered air diving air breathing gases gas blending techniques jurisdictions suppliers breathing gases required legislation periodically test quality compressed air produced equipment display test results public information standards industrial gas purity filling equipment procedures allow levels unsafe breathing use breathing gas high pressure harmful fatal special precautions need taken gases air oxygen high concentrations major cause fire oxygen carefully transferred cylinder stored containers cleaned labeled oxygen use gas containing proportions oxygen extremely dangerous divers unaware proportion oxygen cylinders labeled composition cylinders containing high oxygen content cleaned use oxygen oxygen service reduce chance contaminated air depth fatal common carbon product carbon dioxide product oil keeping cylinder slightly times storage transportation reduces possibility inadvertently inside cylinder agents sea water toxic material poisonous gases fungi bacteria normal dive end pressure remaining cylinder emergency ascent gas incident cylinder normally contain pressure cylinder submerged deeper gas possible water dive contamination water filling causes inadequate drying compressed air introduce small quantities fresh water water failing clear cylinder valve water wet dive gear allow contamination fresh cause contamination cause cylinder rapidly extent unsafe condemned fairly short period problem exacerbated hot climates chemical reactions faster prevalent filling staff badly trained blast caused sudden release gas pressure inside diving cylinder makes dangerous greatest risk explosion exists filling cylinders known burst cause failure range reduced wall thickness deep pitting internal neck thread failure incompatible valve threads cracking fatigue sustained high stresses effects aluminum inspection testing countries require diving cylinders checked regular basis usually consists internal visual inspection test inspection testing requirements cylinders different requirements compressed gas containers environment united_states annual visual inspection required require test years visual inspection requirement diving industry standard based observations review european_union countries visual inspection required years test years norway test including visual inspection required years production date years legislation australia requires cylinders tested months south_africa test required years visual inspection year current testing neck threads according manufacturer recommendations test involves cylinder test pressure usually working pressure measuring volume test permanent increase volume tolerated level means cylinder fails test permanently removed service inspection includes external internal inspection damage correct colour markings failure criteria vary according published standards relevant authority include inspection electrical arc pitting line general cracks thread damage permanent markings colour cylinder manufactured specification including manufacturer working pressure test pressure date manufacture capacity weight stamped cylinder cylinder passes test test date test date countries germany punched shoulder cylinder easy fill time international standard stamp format operators required check details filling cylinder refuse fill non standard test cylinders safety cylinder filled testing dates visual examination external damage required law jurisdictions legally required places test dates checked looking visual inspection test date stamped cylinder use user verify contents cylinder check function cylinder valve usually connected control flow pressure gas mixture critical information valve open freely sticking leaks seals breathing gas cylinder checked smell gas smell right breathing gas free smell slight fairly common smell products volatile failure recognize gas cylinder divers conducting pre dive evaluation noted assembled setup delicate computers inside walked boat bench secured rack practice competent set life support system person touch gear knowledge approval cylinders exposed temperatures cylinders filled pressures greater developed pressure appropriate certified working pressure cylinder cylinders clearly labelled current contents generic label alert user contents air analysed use parts world label required specifically indicating contents air places colour code additional labels indicates default contents air fire pressure gas cylinder rises direct proportion absolute temperature internal pressure exceeds mechanical limitations cylinder means safely vent gas atmosphere vessel fail vessel contents present event result explosion accidents major diving accident fatality research studies conducted globally including work identified cases mortality associated diving cylinder recorded accidents associated diving cylinders valve ejected mix valve threads caused damage dive shop room dive instructor leg nearly ejected valve attempting remove valve cylinder valve ejected filling thread failure sank dive boat cylinder replaced solid bolts filling failure severely injured operator hit face wound exposed jaw bone close wound cases lateral reported caused handling diving cylinders handling cylinders left standing secured fall reasonably circumstances impact damage cylinder valve mechanism fracture valve neck threads likely thread happens energy compressed gas released second accelerate cylinder speeds cause severe injury damage surroundings long term storage breathing quality gases normally deteriorate storage steel aluminium cylinders provided insufficient water content promote internal stored gas remain unchanged years stored temperatures allowed working range cylinder usually doubt check oxygen fraction indicate gas changed components unusual indication cylinder gas contaminated time filling authorities recommend releasing contents storing cylinders small positive pressure transportation diving cylinders classified dangerous goods transportation purposes hazardous materials selecting proper shipping known way help ensure dangerous goods offered transport accurately represent hazards dangerous goods regulations 55th edition defines proper shipping describe particular article substance shipping documents appropriate international maritime dangerous goods code code defines proper shipping portion entry accurately describing goods shown upper case characters plus letters form integral international air air states provided pressure diving cylinders bar psi carried checked carry baggage maybe necessary cylinder verify emptied cylinder valve closed prevent moisture entering cylinder security restrictions implemented individual countries limit carriage items permitted security screening agencies right refuse carriage certain items europe carriage dangerous goods legislation europe road transport amended carriage dangerous goods use pressure equipment regulations regulations implement european agreement concerning international carriage dangerous goods road dangerous goods carried internationally road vehicles comply standards packaging dangerous goods appropriate construction operating standards vehicles crew regulations cover transportation gas cylinders vehicle commercial environment transportation diving gas cylinders combined water capacity litres vehicle personal use exempt transport gas cylinders vehicle commercial purposes follow basic legal safety requirements specifically comply driver vehicle legally responsible safety vehicle load carried insurance vehicle include cover carriage dangerous goods diving gases including compressed air oxygen non toxic non rated transport category threshold quantity gases litres combined water capacity cylinders pressure rated working pressure cylinder air cylinders atmospheric pressure rated transport category threshold quantity commercial loads litres threshold level exempt requirements comply basic legal safety requirements including driver training cylinders transported open vehicles open containers trailers gas tight bulkhead separating driver load cylinders carried inside vehicle ventilation gas cylinders carried inside vehicle space people windows kept open allow air cylinders secured transport shall project sides ends vehicle recommended cylinders transported vertically secured appropriate cylinder closed whilst transit checked leaks applicable protective valve caps covers fitted cylinders transporting cylinders transported equipment attached valve outlet etc fire required vehicle gas cylinders transported date periodic inspection test transported date inspection testing disposal cylinders kept cool ambient temperatures places exposed sources excessive heat product identification labels attached cylinders identify contents provide safety advice removed necessary mark label vehicle carrying dangerous goods threshold level use hazard labels assist emergency services displayed hazard labels removed relevant dangerous goods transported journey complete gas cylinders immediately vehicle loads threshold comply requirements usa transportation hazardous materials commercial purposes usa regulated code federal regulations title transportation abbreviated cylinder containing kpa greater non compressed gas transported commercial purposes classified hazardous materials terms cylinders manufactured dot standards special permits issued filled authorized working pressure legal commercial transport usa provisions conditions regulations cylinders manufactured outside usa transported special permit issued solid metal composite cylinders working pressures bar psi manufacturers surface transport commercial transportation breathing gas cylinders combined weight pounds commercial transportation company transport cylinders combined weight pounds requires manifest cylinders tested inspected federal standards contents marked cylinder transportation safe manner cylinders restrained movement special licence required dot regulations require content labels cylinders regulations according psi breathing air enforced oxygen non air labelled private non commercial transport cylinders covered regulation air transport tanks tanks kpa restricted hazardous materials cylinders allowed checked baggage carry cylinder valve completely disconnected cylinder cylinder open end allow visual inspection inside gas cylinder colour labeling worldwide colours permitted diving cylinders vary considerably region extent gas mixture contained parts world legislation controlling colour diving cylinders regions colour cylinders commercial diving underwater diving specified national standards recreational diving settings air widely gases cylinders identified green stripe yellow background aluminium diving cylinders painted coloured left natural silver steel diving cylinders usually painted reduce yellow white increase visibility industrial cylinder identification colour tables yellow shoulders means generally europe refers cylinders toxic contents significance gas fittings compatible cylinders partial pressure gas blending pure oxygen required display oxygen service certificate label indicating prepared use high partial pressures gas oxygen european_union european_union gas cylinders colour coded according standard optional shoulder cylinder parallel section pillar valve mixed gases colours bands quarters air white black band shoulder white black shoulders white brown band shoulder white brown shoulders like air white black band shoulder white black shoulders pure oxygen white shoulder pure brown shoulder white black brown shoulder breathing gas cylinders labeled contents label state type breathing gas contained cylinder offshore breathing gas containers offshore use coded marked according colour individual cylinders allows body cylinder colour likely cause hazard identified colour code shoulder south_africa cylinders required comply colours markings specified cylinder colour golden yellow french grey shoulder cylinders containing gases air medical oxygen transparent label stuck shoulder word green composition gas listed cylinders containing medical oxygen black white shoulder
Diving cylinder