E

E

FIGURE 13.2 Full-Face Masks for Use in Contaminated

13.3.3 For exposure to chemical or biological that can produce severe illness or death, divers should be equipped with a full coverage , a dry with a mating yoke FIGURE 13.3 for the helmet, and mating dry gloves. The advantage of a Schematic of Reclaim System with Topside Supply over a full-face mask is that 's entire head is encapsulated in a dry environrnent. Diving helmets are also less likely to be accidentally pulled-off a diver's head and they are less prone to leak. (see Figure 13.4). The SEV helps prevent a back-flow of The tvpical mode for supplying gas to a full- water into the helmet. Both the regulator exhaust and the coverage helmet is frorr a sur face-supplied source. Such main helmet exhaust are linked together with a special rube, sources consist of either a low- air or a and a third external exhaust is added to the system. high-pressure gas storage system that is reduced to low pres- Any water that manages to sneak past this outer exhaust sure. Another, more sophisticated mode of supplving gas to valve is unlikely to make it past either of the two other a diving helmet is a "reclaim" gas svstem. A reclaim svstem, . Testing bv NOAA using dye tracers revealed the pres- also referred to as a "push-pull" system, routes the helmet's ence of occasional droplets of water behind the outer-most exhaust to the surface, by raeans of a separate , where rt valve, however, none were detected inside the second valve. is either recycled or exhausted to the surrounding atmos- phere (see Figure 13.3). The advantage ofthis type ofsystem 13.3.4 Umbilicals is that it reduces the possibiliw ofcontaminants entering the One of the big problems with umbilicals for surface- helmet via a back-flow through the exhaust valve (see Figure supplied diving in the past has been that they have tradi, 13.4), and protects the tender from volatile contaminants tionally been assembled with duct tape, which can absorb being released from the sediment and transported to the sur- contaminants or even disintegrate when used in contami- face with exhaust bubbles. The disadvantage is that they are nated water. New umbilicals are available today made more expensive and not easily deployed on a small . from chemically resistant that are manufactured in Special reclaim systerns have been deveLoped specifically for a spiral and require no tape to hold the components polluted-water diving ( 1997). together (see Figure 13.5). These are preferred for many Diving helmets that are equipped with demand regula- polluted-water diving scenarios. tors, without reclaim systems, are subject to the same exhausr "splash.back"problems experienced with open-crr- 13.3.5 Dry cuit scuba regulators. To reduce the possibility of this hap- If a is to be used with a full-face mask, the dry pening, NO.dA developed the "series exhaust valve" (SEV) suit must be equipped with a latex or vulcanized rubber

t3-6 NOAA Diving Manual

L-r*"r---. @) 6"r, >^ \vl FIGUBE 13.4 Double Exhaust System

dry which is attached directly to the suit (see Figure NOAA and the EPA conducted tests in the 1970s with 13.6). The full-face mask must seal on the hood without different types of dry suits in several biologically contami- leakage. If the diver is using a full-coverage helmet (see nated dvers. After decontamination, it was determined that Figure 13.7), the inteface between the diving helmet and suits with a fabric exterior showed signs of bacteria the dry suit is extremely critical. Ideally, the helmet should for several days after the dive. In contrast, vulcanized rub- mate directly to the suit, quickly and easily. yet, the ber dry suits displayed almost no evidence oFbacteria after connectron must be positive and secure. The system should proper wash down. Based upon these tests, vulcanized rub- be designed so that few, if any, contaminants are trapped ber dry suits have become the most widely used type of suits for diving polluted between the helmet and the suit when the two are seDarat- in water. While vulcanized rubber ed after rhe d:r e. dry suits help protect the diver from most biological conta- mination, they do not protect him from all types Dry suits for contaminated water diving should be of chemi- cals or radiation. made from a material that has a smooth, non-porous outer surface. The material must not absorb or trap contaminants. NOIE For diving in biologically polluted water, vulcanized rub, No type of diving helmevmask or suit can guarantee ber dry suits are the most popular choice. complete protection from exposure to contaminants under Water.

Dry suits used in a contaminated environment must also be equipped with attached . Suits with thin latex are unacceptable, due to the with which the material can be punctured, especialiy when walking on the bottom ofa garbage littered harbor. Dry systems consisting of a set of cuff rings and gloves (or mittens) should also be used for polluted-warer diving operations. Cuff rings come in pairs of inner and outer dngs. The inner ring, which is machined from hard , goes inside the sieeve of the drv suit where the slee|e attaches to the rvrisr seal. The outer ring. $'hich is made lrom rubber'. sljps or'er the sleer.e.ind colnpresses ti.te Etn || atr r a E iu:: o|e r lhe :nte: : ilt,{. Ta

D^ll"r-J \I--- -- T-l:-:-- FIGURE 13.6 Full-Face Mask with Dry Suit

fhe clamp to pre\ cnt it fronr , ol tape ma_v be used aLone to hold the llloves in position. The dr1 gloves or ' tcr.ls snap into position ovef the outer ling (see Figule

1 3.8). It is essential to remembcr that anv individual piece oI cliving gear ivill not be compatible rvith all chemical FIGURE 13.7 e rlvironments. In 1983, thc U.S. Navy's Sulface Weapons Cente r commissione d a studv on the eff'ects of a variety of Full-Coverage Helmet with Dry Suit hazardous chemicals on (Glowe 19E3). The tests. which were pe llbr ne d by thc TRI Environmen- tal, Inc., coverecl a wide Yaric't! of mjlitar\' and commer- cial diving equipm€nt. The rcsults of immelsion tests of I3.4 POLLUTED-WATER DIVING sclected suit ancj helmet components and Gates C3 diving TECHNIQUES hose to chemical cxposule are available frrrm the NOAA Diving in contaminated water is not much different Diving Ccnter (NDC), Seattle. Washington. In 199E. than diving undcr ordinarl conditions. The procedurcs and Trelleborg Viking conductecl permeabilitl and resistance techniqucs used under water are basicall_"- the same as thcy lusl5 on theif \ul!,tr'r.z(d rutheI drr suit:. l.rrcr are lor any surface supplied dive. The real differences in seals. and glovcs for various chemical ex1'rosures. These diving in contaminated water are thc procedures and tech- lesults are also available from NDC. niques that takc place before and aftcl the dive. Gcar set- In addition to protectillll the djver. tl'r!' diver's ten- up, -in procedures. air supply systems, and dcrs. rvho aid hirrr in dressing and handie thc divir.rg hose, decontamination are quite dilferent wheu diving in conta- must also be properly protected. The tenders u'ill be in minated water as compared to diving in less hostile envi- the "hot zonc" whtle the), tend the divcr at the watef's IOnmenIS. edgc (see Figurc 13.9). They must also accompany and The preparation fbr a contaminated water dive actual- assist the diver thlough thc dccontanlinatir:rn procedure. ly starts rvith team training. Even though the divcr may be Tenders must wear the appropr iate protectioll according very experienccd. the extra equipment lequired fol conta to the hazar.d ler,el (Balskv 1999). Besidcs dressing thc minated rvater diving usuallv requires cxtra training for clivcr, they must keep a firm grip on the diver's umbilical personnel. The diver must become thoroughly familiar at all times. Since they cannot leavc the diver's hose unat- with the c1ry' suit. full-face mask or hclmet, and any other rcrde.l. tl^cv rru5l he pr,'viJr'J u ith a sullicrelt air 'ul gear to bc utilized. Both the diver and tenders must be ply. if the situation warrants it. The au. supply must last familiar u'ith the decontamination procedures. A difflcult lbr rhe anticiparcd duration of the drve, as u'ell as includ- and important part ol contaminated water diving is dress- ing a reserve. Tenders mLLSI also be prorected from heat ing the divcr quickly ancl efficiently so that he docs not stfess. become overheat€d.

13-8 NOAA Divine Manual

.&, ,qfl

Diuer and

5.0 GENERAL .r TLe -e nf rlir ino -n,,inrp-r rhe diver \,\eals has a tremendous impact on the diver's ability to work comfort- ably, safely, and efficiently (Bachrach and Egstrom 1986). Although equipment is a big factor in diver performance, equipment alone cannot make up for a diver's lack of abili' ty in the water. A good diver must have a high level of fit- ness and must be comfortable in the water. A competent diver should be able to dive with most any type of equipment provided he has been trained to use it. Selecting the right dive gear for a scjentific dive is a mat- ter of defining the objectives of the dive and the location. For some work, equipment may be al1 that is required, while for otherjobs surface-supplied gear mav be the best choice. A diver must become totally familiar with neu equipmerrr before entering a uorking situarion With all diving equipment, remember that streamlin' FIGUBE 5.1 ing is an essential factor in making it easy fol the diver to Dive Mask with Nose Pocket swim and maneuver under water. The more equipment the divel wears, the more and change of center of gravity will be created. Each piece of equipment should have a def- inite purpose on a particuLar dive; and if it is not going to s.l BASrc EQUTPMENT be used, it should not be carried. Streamlining is crucial to 5.1.1 Face Masks producrir iry for the scienrrfic diver. face rasks [or ale de:igned to rovo rhc Given the durability of most diving gear, making the eyes and nose. The nose must be included inside the mask dght selection at the time of purchase is critical, since it is to allow the diver to equalize the plessure inside the mask hard to justii/ equipment replacement if the equipment is by exhaling through his nostlils. This is one of the reasons not worn out. By talking with diving officers and other sci that goggles that cover only the eyes are not acccptable for entific divers, the preferred models of gear for a particular diving. location and type ofdiving are easily identified. A critical issue in selecting a mask is the fit. The mask The NOAA Diving Program has a standardized equip- must fit comfortably and not leak. To test the fit, the divel ment program whereby all active NOAA divers are issued places the mask against his face as he would when wear- dive equipment. The program, which includes yearly main- ing it normally, but without using the strap to hold the tenance and testing of all scuba regulators, pressure and mask in place. The diver then inl'rales through his nose, depth gauges by a factory-trained NOAA technician, pro- holds hjs breath, and attempts to make the mask seal vides standardization of equipment for all NOAA divers against his face. If no air leaks into the nask and the rnask and helos ensure oualitv control. stays in position, it can be considered to be a good fit, as

5-l long as it is comfonable. Divers with mustaches having dif- Many snorkels today are available with mounted ficulty achieving a mask seal may have to use some type of valves that help to keep water out of the while substance such as Vaseline! on their mustaches to achieve surface . These valves are not designed to seal a proper seal. the snorkel under water but to keep spray from flooding Many dirers find thar a nose pocker is a useful fea- the snorkel while the diver swims on the surface. These ture of a mask in that it provides a means fol the diver to can be extremely effective and make surface swimming pinch his nostrils closed in order to aid in equalizing the much easier. pressure in his ears (see Figure 5.1). Other features include Most modern snorkels use plastic rings or attachment purge valves and double feather edge sea1s. A purge is a devices to connect the snorkel to the diver's mask. These one-way valve through which water can be expelled that rings allow the snorkel to be easily removed from the enters the mask. Water can also be removed from a mask mask, so that the mask can be stored in a protective box without a purge. A double feather edge is a type of sealing for transport to and from the dive site or during airline (double) edge on the material that fits against the face. travel. Once it js determined that the mask fits properly, the In the United States, the snorkel is traditionally mount- next most critical feature is visibility. Side windows in the ed on the left side of the diver's head, since the regulator is masks can enhance peripheral vision (Egstrom 1982), but routed over the diver's right shoulder. In Europe, the oppo- can sometimes produce a "rear view effect. " Mask win- site arrangement is sometimes employed since the regula- dows are made from safety-tempered glass. Additionally, tor may be directed over the diver's left shoulder. some masks have downward lenses or optical devices that will help the diver see more of the equipment mounted on 5.1.3 his chest and . Fins for scuba diving are usually much more rugged For divers who require glasses, prescription lenses are and have larger blades than those used for snorkeling or available that will flt many popular dive masks. For swimming. The fins provide propulsion for divers who are divers who have a common prescdption and do not need heavily encumbered with equipment and make underwa- bifocals, many dive stores stock lenses for their more pop- ter swimming much easier. Human leg muscles are very ular mask styles. Divers who have an unusual prescrip- efficient for underwater propulsion when properly tion will need to order specially prepared lenses for their equlpped. masks. When divers are fully geared up, it may not be possible The lenses of new masks need to be washed with a for them to use therr hands for .r,r imming purpoies. iince mild liquid detergent, such as dishwashing detergent, to straps and thermal protection suits inhibit normal arm help remove any chemicals that may remain from manu- movement. In addition, scientihc divers are usually carry- facturing and may cause the mask to fog. ing instruments, slates, or other equipment that make it rmpractrcal Lo use I heif drms for trr rmming. 5.1.2 Snorkels The human leg provides propulsion under water by A snorkel is an indispensable piece of equipment for moving the levers of the body, i.e. the femur and tibia, to the open water scuba diver using self-contained open cir- provide thrust through the use ofthe f1ns. Since these bones cuit gear (see Figure 5.2). The purpose of the snorkel is to are of different lengths in each individual, providing a differ- a1low the diver to swim more easily on the surface without ent mechanical advantage for each diver, there is no one consuming the compressed gas in his cylinder. that will work best for each person. A fin that works very Ideal1y, the snorkel should not exceed 14 inches in length and should have the minimum number of berds possible. If the snorkel has a corrugated hose, allowing it to bend easily, the inside bore of the hose must be smooth, not ribbed. Small diame- ter snorkels, and those with corrugated hoses with internal ribs, produce high breathing resistance, add substantially to equipment dead air space (where no takes place), and a corrugated hose F Al also makes elimination of all water in the snorkel all but impossible.

FIGURE 5.2 s FIGUBE 5.3 Snorkel with Attached Snorkel Holder Adjustable Heel Slrap Fins

)-z NOAA Divine Manual 5.2.1 Dive Skins There are many different types of thin suits available that provide sun protection as well as protection from cuts, scrapes, and stinglng creatures such as . These suits are form fitting, have good stretch, and are generally refefied to as "dive skins" orjust "skins." Skins made fro'r Lrcra provide good prolecr'on lro* the sun but do not provide any thermal protection. There are also suits made from Lycrai combined with additional materials such as polyolefin microfibers which provide good wind resistance. Dive skins may be worn in tropical when the diver's activity level is relatively high. During warm water dives where the diver will remain relatively inactive, a wet FIGURE 5.4 sult or Poladec\ skin, which provides insulation equivalent Full-toot Fins to a 2-millimeter suit without the same buoyant propefiies of a wet suit, is recommended. In some cases where buoy, ancy is desirable, wet suits made from mbber are recom- nended.

5.2.2 Wet Suits Wet suits are made from foam , a synthetic material with thousands of tiny closed cells that are fll1ed with nitrogen gas (see Figure 5.6). The suits are designed to allow water to enter the area between the diver's skin and the suit. Ideally, a wet suit should fit snugly, allowing only a minimurn of water inside the suit. This thin layer of water is warmed up by the diver's body and provides rea- sonable comfort at moderate . A cold water wet suit usually provides FIGURE 5.5 a double layer of insulation over Booties th€ torso- Wet suits come in a variety of thicknesses, one mil- limeter up to seven millimeters. They also come in numer- well for one diver may not work satisfactodly for another, oui designs. inc ud'-g :horty surrs. one-piece )uits. and therefbre, divers may have to try several different rypes and multi-piece suits. sizes before finding the best set offins for their use. For warm waters, above 80'F (26.7C), a one-piece Fins come in two styles, the open heel adjustable fin and suit, two to three millimeters thick, may be all that is neces- the full-foot pocket fin (see Figures 5.3, 5.4). Fins are made sary for most divers. As the water drops, from either rubber or graphite and are available in different thicker suits and multiple layers of insulation become nec- foot pocket sizes. While full-foot fins, without booties, are essary. For example, in Southern California, the preferred frequently used in the tropics, the_v are rarely used in colder wet suit is usually six or seven millimeters thick with a waters. One of the disadvantages to the full-foor fin is that "farmer john" set of bib and ajacket ofthe same when the fbot pocket wears out, the fin cannot be repaired. material with an attached hood. fhe open hcel adjusrable fin is norm"l 1 worn wrrh nco- The use of zippers in wet suits is a personal preference prene booties (see Figure 5.5). The major advantage to this of thc direr. Whrle zippers make ir easie- to don d sutr, type offin is that ifthe heel strap breaks, it can be replaced. they also increase the cost of the suit, decrease reliability, and allow more water to enter the suit. Most wet suits have a nylon exterior coating to help 5.2 THERMAL PROTECTION reduce abrasion to the r-ubber and a nylon interior to make The type of thermal protection will be determined by it easier to don the suit. Some divers prefer a suit without a the water temperature, the diver's work 1oad, personal nylon lining and use a diluted of hair conditioner physiology, and any contaminants thar may be present in or talcum powder to make the neoprene surface slippery the water. Each ofthese factors is important, but it is essen- enough ro slide eas ly orer rheir skin. tial for the diver to pay attention to his own comforl level Wet suits are very buoyant on the surface. For this in the water. While a large male may be comfortable in a reason, divers usually wear a when wearing six millimeter wet suit in 62'F water, a small female may thls type of thermal protection. However, as the diver be extremely uncomfortable. descends and the suit compresses at depth,

Diver and Diving Support Equipment 5-3 TABLE 5.1 Etticiency of Wet Suits vs. Dry Suits

Wetsuit Drysuit warer 1st 2nd 3rd lst znd 3rd Iemperarlre Dive Dive Dive Dive Dive Dive 70"F 100%'100% 100% 100./. 100% 100% 60'F 100% 900/o 800/. 100% 1000/. 100% 50"F 80% 70% 50% 100% 100./. 100% 40'F 50y. 25./. . 100% 85% 75./. 32',F ' 1004k 75% 55%

Table is based upon 3o-minute dives al50lsw, with one hour surface intervals between dives. The * indicates an exDosure not recommended unless involved in a continoencv situation.

boots, and seals at the diver's wrists and neck. Tbe suits are normally designed so that iDsulating may be wom bencath them. These undergarments trap a layer of air that provides primaw protection against cold. By varying the amouDt ol underwear (insulation) worn undemeath the dry suit, it is possible to dive in a wide vari- ety of water temperatures. When purchasing a suit, the diver should try the suit on u,ith the thickest underwear he anticipates using to ensure a proper fit. Dry suits can increase a diver's bottom tirre dramatical- ly, since the diver's body doesn't need to "burn" as many calories to keep rvarm. Kecping the diver warm will enhance FIGURE 5.6 his perfbrmance and lower the risk of h.vpothermia. Cold Water Wet Suit Dry suits are made liom a variety of materials, including foam neoprene, crushed or compressed neoprene, tri-lami- decreases and the diver must adjust for this char.rge of nates, urethane'coated fabrics, and vulcanized rubber. Each buoyancy. Betwcen dives. the water that has treen trappcd type of material has advantages and disadvantages. A heav_v inside the wet suit nolmally leaks out. This causes a loss in dut_v suit made of \,.ulcanized mbber, fol example, is worn with body heat. In addition, divers wearing wet suits are sub- cold rvater undergaments and is available with mating yokes jected to evaporative cooling as the wind blows over thcir to accomrnodate various diving helmets (see Figure 5.7). suit and the water on its surface vaporizes. Foam neoprene (wet suit material) is the least expensive The cells of the mateial that provide the insulation for rype of dry suit. It has good stretch and thermal character- the wet suit begin to break down over time due to age and istics, but tends to develop leaks over time as cracks occur use. When this happens, the suit loses much of its insula- in the neoprene bubble layers and water migrates through tion value. the material (see Figure 5.8). Wet suits are most effective at water temperatures above 60'F (15.6C); in colder waters. a dry suit is generally recommended (see Table 5.1).

5.2.2.1Maintenance of Wet Suits Proper care ofwet suits, like all dive gear, is critical to ensure long life and reliability. After each day of diving, the suit must be thoroughly rinsed with freslr, clean water and allowed to dry. Avoid hanging the suit in the sun to dry for long peliods or for permanent storage. Heat and ultl-aviolet rays from the surr will deteriorate neoprene; thercfore, store the suit jn a cool, dark, and dry location.

5.2.3 Dry Suits Dry suits are the most efficier'rt form of passive thermal FIGURE 5.7 protection for the diver. Dry suits are designed as one-piece Heavy Duty Suit Made suits rvith a waterproof for entering thc suit. attached of Vulcanized Rubber

J-+ NOAA Diving Manual ,.rtfl

Tbe most common location for the inflator valve is the middle of the diver's chest. Inflator valves must never be covered by the diver's buoyancy compensator, which can make it difficult to access the valve and lead to runaway irflation accidents. This can occur when the buoyancy compensator (BC) bladder pushes on the suit valve causing the valve to inflate the suit. As the suit inflates, it pushes the valve against the BC, which causes it to continue to inflate. The inflator valve is supplied with air from a low pres .ure hose rh.1r con-ccls ro rhe lr:t sldge of tLe drver s regu laror. Thc ho.c ru'L o"lv be connected to a Iou-pres.ure nit,r Hioh nre..rrre hre:thino u:- en,eriro thp hn.p u ill FIGURE 5.8 cause the hose to fail. Foam Neoprene Dry Suit The inflator hose must be equipped with a quick dis- enrne, t firriro .,, ,h.r rhc hn.c r-n hc imme,l,,rel, Crushed and compressed neoprene are mgged dry-suit released from the valve in the event the valve sticks in the materials that have good stretch and some inhcrent insula, open positlon. The quick disconnect must be easy to oper- tion. The disadvantages to this type of suit are its relatively ate so rhar ir can be rcrored, or r(cunnected, everr rf tlre hp;rn ureiohr:rrl hiohe, enff diver is wearing thick gloves or three-finger mitts. TLS stands for tri'laminate suit. This is an extremely Divers working in very cold water or using - lightweight material orjginally developed for chemical war gas mixtures sometimes use a suit inflation system fare. The material is very llexible and leasonably rugged. The that is independent of their supply. In these disadvantage of suits madc from this material is that they situations, the preferred suit inflation gas is , which is don't stretch. rormallr .upplted fron a -tnal cylinoer rrou-ted o- the Urcthane-coated nylon material is sinilar in appearance thigh ofthe diver's suit (Barsky et al. 1998). When this type to TLS but not nearly as flcxibie nor as reliable. The advan- of system is used the inflator valve will usually be mounted tage to urethane-coatcd rylon dry suits is lorv cost. on the thigh as well. Vulcanized rlLbber material has some stretch. but not No e rpiri. al dara e\'.ri on rhe effecrs of argon nearly as mucl-r as crushed or compressed neoprene or foam absorbed transdermally on a diver's obliga- oeoprene. Vulcanized rubbel dries quickly and is quick and tion. For this reason, divers should be conservative in easy to repair. One disadvautage ofvulcanized rubber suits is using this type of system. that the)' cannot be tailored to be as form fittilg as crushed The exhaust valve should be a 1ow-profile valve that neoprene or TLS suits. They are also relatively hear.ry suits can be vented either automatically or manually during when compared to TLS or urethane. Vulcanized rubber suits ascent. The nost common location for the exhaust valve is ale preferred lor diving in contarrinated water because they on the left arm on the outside although a chest mounted arc the easiest ofall c1ry suit t,vpes to decontaminate. valve is not uncommon. The exhaust valve must vent air faster than the inflator valve can supply it to the suit. NO]IE Different models ofvalves vent at different rates. A faster Polluled-water cliving requires specialized equipmeni exhaust is better sjrce it allows a diver to dump the air fronl and training (see Chapter 13 for more information). his suit more quickly (Barsky, Long, and Stinton 1996). Even the same models of valves will not always vent at the The two main styles of dry suits are shoulder-entry suits same rate due to differences in manufacturing tolerances, and self-donning suits. Again, both types of suits have their wear, maintenance, etc. advantages and disadvantages. Also, dry suits are designcd with boots with either hard or soft soles. 5.2.3.2 Dry-Suit Seals and Accessories With a shoulder'entry suit the divcr ltets into the suit Drv suits are equipped with seals at the wrists and through the back bi opening the watcrproof zipper. The dis- neck. These seals can be either latex or neoprene. advantage ofa shoulder-entry suit is that it requires assistance Latex seals are the softest, thinnest, most flexible seals to get in and out ofthe suit. availabie and can be cut to fit the individual diver. Howev- Self-donning dry suits have the major advanrage of el, latex seals are not as rugged as neoprene seals and are allowing the diver to get in and out of the suit by himsell more prone to danage if mishandled. In areas with heavy The disadvantage is that self donning suits are usually more smog. latex seals usually orly last airout a year before they e\pen5i\. llr,jn a .imila..houlder-cnrr1 suir. musl b( eplaced due to rubbei dererioration. Latex seals can be ordered in different thicknesses. 5,2.3.1 Dry-Suit Valves Thrcker latex seals last longer and are more reljable, but can Most dry suits today have separatc intlator and exhaust be troublesome to don and remove. Some dry suits come valves. This is the preferred arargement to avoid getting $.ith or may be adapted for use with a cuff ring system that water in the suit and for the most precise buoyancy control. allows change ofcuffrings, seals, and the use of dry gloves.

Diver and Diving Support Equipment 5-5 Both latex and neoprene seals should be dusted with loses control of the object, he will become positively buoy- pure talcum powder pdor to donning. Do not use scented ant, which can lead to a rapid ascent. Rapid ascents are talcs which contain oils and can damage the seals. If no tal- dangerous and can cause lung over-pressure injuries and cum powder is available, soapy water may be used as an omltted decompression. altemative. Neoprene seals are more rugged than latex seals Some manufacturers recommend the use of buoyancy and can last for several years. The negative side ofneoprene compensators with dry suits. The buoyancy compensator is seals is that they tend to leak more than latex seals. used primarily for surface flotation and as a back-up device Proper donning of suit cuffs is absolutely critical to a in the event of a catastrophic dry-suit failure. Divers who dry dive. Jewelry, rings, etc., should be removed when are more heavily weighted with multiple cylinders may donning neck and wrist seals to avoid damage to the seals. need to use the buoyancy compensator in conjunction with the suit under water. Controlling two independent flotation 5.2.3,3 Dry-Suit Zippers systems (the dry suit and the buoyancy compensator) at the The waterproof, pressure-proof zipper is what made same time is considered an advanced skill and requires the modem dry suit possible. These zippers are very similar additional training and practice. to the zippers used in space suits. Just as a heavier latex seal is more reliable, the heavier 5.2.3,5 Dry-Suit Underwear the zipper the more rugged and damage resistant it will be. Several different types of dry-suit under-wear are avail- The most heavy-duty zippers have individually pinned able in different thicknesses. The three most popular types "teeth" which can be replaced if broken. Lighter weight of matedal used are Thinsulate *, PolartecR, and synthetic zippers must be completely replaced when damaged. fleece. Special care must be taken to ensure that no dry-suit Thinsulates is made from polyolefin microfibers. The underwear, hair, or other foreign material is caught in the most important feature of Thinsulate3 is that it is water zipper when it is closed. Not only would this cause the zip- resistant and maintains most of its insulating capabilities per to leak, it may also cause the zrpper to break. Dam- even when it is wet. Undergarments made ofThinsulates a.ge/wear to zipper teeth can be minimized by not twisting have more bulk than most other types of dry-suit under- the zipper at angles oblique to the normal linear direction wear. They also do not stretch or breathe and are not as during donning and removing the suit. comfortable to wear as some other types of undergar- Dry-suit zippers should be lubricated with bee's wax menrs. prior to closing. The lubrication should only be applied to Polafiec" is another synthetic matedal that is widely the outside of the zipper, never on the inside. Paraffin wax used as dry-suit underwear- Polartec3 is easy to don and may also be used and even a bar of soap can be used if no the material has excellent stretch, which makes it easy to other lubdcant is available. swim and move. The material has good insulation charac- spray should never be used to lubricate a dry- teristics with very little bulk, but it does not maintain its suit zipper, or any other part of the suit. Silicone spray insulation capabilities once it is wet. For this reason, it is works its way into the fabric of the suit, making it difficult not recommended for critical applications such as diving to get a good bond between the suit and replacement parts under the ice. that must be glued to the suit when it is time to make Synthetic fleeces are comfortable to wear but do not repairs. offer the insulating capabilities of either Thinsulate. or PolartecE. They also do not have the stretch capabilities of ! 5.2.3,4 Dry-Suit Use Yolartec . A11 divers who use dry suits must be trained to use As the diver varies his insulation, his buoyancy will them properly. Although dry suits are not dimcult to use, change. Thinner dry-suit underwear traps less air and accidents have occurred when divers who were untrained requires less weight than thicker material. This must be have attempted to use them. considered as the diver makes changes in his insulation Under normal conditions, dry-suit divers control their with the season, when traveling to another location with buoyancy under water by introducing air into the suit or different conditions, or with his work rate. buoyancy compensator, if a BC is woru. The air is also used to ofBet the effects ofpressure to prevent suit squeeze. 5.2.3.6 Dry Suits and Dry-Suit Underwear Maintenance To control buoyancy upon ascent, the air must be vented Dry suits require more maintenance than wet suits to out of the suit as it expands. Dry-suit divers should keep a ensure consistent performance. The seals, zipper, valves, thin layer of air in the suit at all times for thermal insula- and suit itself musr receive regular atrention. tion. This may mean adding weight to the weight belt to At the end of each diving day, the exterior of the suit, compensate for the additional buoyancy. including the valves, zippers, and seals, must be dnsed thor- The dry suit wom by the diver must never be used as a oughly with fresh water. lfthe diver has perspired inside the lifiing device to lift heavy objects under water. If the diver suit, the interior ofthe suit will need to be rinsed as well.

5-6 NOAA Diving Manual Check inside the suit for perspiration or moisture by reaching all the way dowr inside the suit to the boors. If the boots feel damp inside the suit, the inside of the suit needs rinsing. The suit should be dried by hanging it ro dry over a line or bar out of the sun. Do not use a hanger. If the suit has been rinsed inside, the suit must be tumed inside our to dry the interior, roo. The entire suit. both iDside and out- side, must be complerely dry pdor to storage. Latex seals need to be washed periodically with a diluted solution of dishwashing soap and water. This will remove any body oils or other substances (i.e., gasoline, petroleum products, creosote) the suit may have been exposed to in the water which will cause the seals to deteri- orate. When the seals begin to crack or appear sticky, they wrll need to be replaced by an authorized repair facility. Aside from lubricating the zipper prior to every dive, the zipper should be cleaned regularly with soap and water and a toothbrush, This will help to remove corrosion from the zipper and keep it operating smoothly. A small shot of silicone spray should be applied to the opening of the nipple of the inflator valve and the valve should be operated several times. The valve must work smoothly and not stick. FIGURE 5.9 Dry suits should be stored rolled up, in a bag, in a Hot-Water Suits cool, dry place, away from sources of , such as hot- water heaten or electric motors. Several days prior to any dive the suit should be removed from storage and inspected available, and this is usually the to ensure it is in good condition for diving. Dry suits most reliable method for heating the water supply. Diesel and powered should be leak-checked prior to initial use each year. This electrical units, as well as "Piggyback" units rs done by plugging the seals, inflating rhe suit, and bnrsh- that draw their heat from the low-pressure compressor ing it with a diluted soap solution. air that supplies the air for the surface-supplied diver, are also available. Dry-suit underwear needs to be laundered periodically The water supply to the diver is controlled using a mix- to remove body oils, stains, and dirt. Divers must check the ing unit similar to that in a household fixture, a instructions supplied with the garment to determine proper but on much larger scale. This mixing unit is normally located at procedures. Improper laundering can ruin some the dive control station topside where the garments, especially Thinsulate 3. diving supewi- sor can monitor both temperature and water flow. The manufacturer for the hot-water system will normally pro- 5.2.4 Hot-Water Suits and Systems vide chans that suggesl rhe appropriate water temperature Hot-water suit systems are the most effective way of to supply to the diver based upon the flow rate, the length keeping a surface-supplied diver warm in cold water (see of hot-water hose in use, and the bottom temperature Figure 5.9). The system consists of a surface heater, a where the diver is working. mixing manifold, a hot-water hose that delivers heated The hot-water hose is a heavy, insulated hose that is water from the topside unit to the diver, and a special bundled into the diver's umbilical. This hose will usually hot-water suit. be the thickest hose in the umbilical. This hose may con- In most cases, these systems will be equipped with a nect to a thlnner hose three to four foot prior to its termina- suctlon pump that will draw raw sea water from over the tion at the diver to provide greater flexibility and freedom srde and supply it to the headng system. On a large ship, it of movement for the diver. may be possible to plumb the sea water intake on the sur- The hose connects to the diver's suit with a quick dis- face heater directly into the ship's raw water supply. connect fitting at a valve located on the suit at the waist. The topside hot-water system can heat the water using The valve is normally a simple, quarter-turn ball valve. a variery of different methods. The location and logistics of Hot-water suits are usually made fiom crushed neoprene the site will usually determine which heating method is or another non-compressible suit material. The suit should ht most practical. On a large ship or barge, steam is frequently loosely. Inside the suit, there are perforated tubes that run

Diver and Diving Support Equipment 5-7 down the diver's chest, back, legs, and arms. Hot water is dis- gloves are normally made ftom foam neoprene. Three-finger tributed throughout the suit by these tubes. The water exits gloves may be worl in colder waters to provide better ther- the suit at the ankles, wrists, neck, and through rhe zipper. mal protection (see Figure 5.1 1). The hot water continuously flushes through the suit. It is recommended that the diver wear a thin (two three 5.2.5.2 Hoods mm) shory wet suit under the hot-water suit. The short), A hood is required if the water is cold enough to war- suit serves several important purposes. First, it provides rant. Standard neoprene wet-suit hoods can be used with some buoyancy, since most surface-supplied diving outfits some dry suits; however, a more preferred hood is one made do not include a buoyancl, compensator. Second, in the especially to seal against the neck seal of the dry suit. These event that the mixing valve fails and scalding hot water is hoods usually have a shon neck, and use skin-in neoprene accidentally sent to the diver, the shorty suit will provide around the neck, and sometimes around the face, to provide some protection fronr burns. Finally, if several divers are a good seal against water intrusion. There are also dry hoods sharing the same suit, wearing a shorty made out ofneoprene or latex that can be attached directly to suit can help prevent fungal infections the dr), suit. The latex hood uses an insulated liner, and being passed from diver to diver. works well in extremely cold environments. They generally do not seal against beards, or on people with very thin faces. 5.2.5 Suit Accessories Their features include: 5.2.5,I Gloves Gloves are worn by most . Ncoprene or rubber tifrubber. an insularing skull divers to protect the hands from made offleece may be wom under the hood) cuts in wann water and for thermal . May be permanently attached to suit protection in cold water (see Fig- . May have a one-way valve at the very top to allow air ure 5.10). Gloves are made in a to escape (other-wise it will balloon-up) variety ofsqvles and fi.om differ- ent materia ls. C old -wa ter Regardless of the type of hood worn, dive6 must be able to equalize pressure in their outer eani to avoid an ear squeeze. Equalization requires allowing water to enter the hood and fill FIGURE 5.10 the outer ear canal. The same requilement can be achieved by Protective Diving Glove allowing air fiom a full-face rrask to flow into the hood and thus, reach the outer ear canal and ultimately the ear drum.

5.3 OPEN CIRCUIT SCUBA RXGI.ILATORS The function of the open circuit scuba regulator is to reduce the high-pressure breathing gas supplied by the scuba cylinder to the at the diver. This is accom- plished in two steps. The first stage of the regulator, which FIGUBE 5.11 attaches to the cylinder valve, reduces the high pressure to Examples of an intemediate pressure that is usually about 140 psi over Three-Finger Foam ambient pressure (see Figure 5.12). This intermediate pres- Neoorene Gloves sure fills the low-prcssure hose which connects the first stage and the second stage. The second stage reduces the interme, diate pressure to ambient pressure. The open circuit regulator in use today is known as a "demand regulator" because it only supplies air when the drver inhales o: "demands" it. When the diver is not inhal- ing, no gas flows through the regulator. The two most common designs for first stages are the piston and diaphragm models. First stages may be pro- duced in either of two configurations: "balanced" or "unbalanced" models. Generally speaking, balanced regu- lators offer higher performance than unbalanced models and are the most common design found today. The first stage of the regulator may be environmentally sealed to help keep contaminants out and prevent freeze-up during operations. Some regulators are supplied from the factory this way, while others may be equipped with this option after purchase.

5-8 NOAA Diving Manual FIGURE 5.14 Open High-Pressure (HP) and Low-Pressure (LP) -t Ports ) is designed to work at higher . With a DIN regula- tor and valve system, the fint stage actually threads into the valve body. The principle behind the DIN fittings is known as a "captured O ring" because once the regulator is screwed into the valve, it is almost impossible for an O-ring FIGURE 5.12 First Stage of the Regulator failure to cause a loss ofbreathing gas. For this reason, DIN fittings are preferred for all overhead environment dives such as wreck penetrations, ice diving, , and The types ofcylinder connections available are the tradi- "virtual" overhead environments, such as decompression tional yoke connection and the European DIN connection. diving (Palmer 1994). Yoke connectors are intended for high-pressure service not The first stage of the regulator must be equipped with a to exceed 3,000 psi. DIN connections are used for cylinciers sufficient number of high- and low-pressure ports to allow and regulators that operate at pressures up to 4,500 psi. (see attachment of all of the accessories the diver will need (see Figure 5.13). Figure 5.14). These may include an additional second stage DIN is an acronym which stands for "Deutsches Institut hose, a low-pressure inflator for a buoyancy compensator, a fuer Normung," which is a European association of engi- low-pressure hose for a dry suit, and a high-pressure hose for neers and manufacturers that sets standards for compressed a pressure gauge. Ideally, the fifit stage will have gas cylinders and valves. Valves manufactured to these stan- enough pods so that the optimal routing lbr each hose can be dards are known as "DIN fittings" or "DIN valves." achieved. Sharp bends or kinks in hoses must be avoided to The DIN connection for regulators and valves is a more prevent gas flow restrictions and premature hose failures. reliable connection than the more common yoke fitting and Some first stage regulators are equipped with swivels that will permit the hoses to tum to help achieve a better angle for hose routing (see Figure 5.15). This is a desirable feature

FIGURE 5.13 FIGURE 5.15 DIN System Threaded Valve Body Hose Swivels

Diver and Diving Support Equipment 5-9 vent gas vilaorously on its own. This loss of gas is comrlon ' 11'' refelrecl to as a liee llou. Most regulator seconcl stages tocla_v are either dorvn- strear-n valves or pilot valves. Downstrcam valves tend to be flore common and are usuallv simpler than pi]ot valves (see Figure 5.17). To achieve higher pclfbrmance, the regulator may be equipped with a "ventur.i" n.rechanism, u,hich promotes highel gas florvs. The venturi increases gas velocity and loucrs prrssurc rrr.rking brrathing t'asrer. Pilot valve regulators off'er high lrcrformance but ter'td to be Dlore expensive than downstrearn designs. Most pilot valve rcgulators are extremely compact and lightweight. In a pilot valve regulator, the demand lever opens the pilot valve fir.st. The pilot valve thcn openS the larllcr main valve provides FIGURE 5.16 that the breathing gas. Pilot valve sccond Cutaway ol Second Stage Regulator stages and more traditional designs may have diver-operated adjustments that are designed to for divers who have manv accessories connectecl to their enhance breathir.rg. In man.u" cases. pilot valve second regLrlators. stages may be cquipped rvith a predive" and "dive' The second stage regulator includes the rrrouthpiece and srvitch that changes the breathing characteristics to prevcnt air loss rvhile surface swimming regu- purge button (see Figure 5.16). When the diver. inhales. a on snorkel when the lower pressure rnside the second stage is created, which lator is not in tLsc. Similarly, some t.egulators arc equipped causes the diaphragm to depress, r.r.roving towa|ds thc rvith acljustment knobs that can be set to make breathing (see dirsr's mouth and acluaring a lcrer. Thc lerer nperrs rhc easier at depth Figure 5.1 8). valve that allorvs air to pass into the second stage and sup Solne seconcl stages have also been engineered ibr ice ply alr to the diver. When the cliver exhalcs, the diaphragm diving opcrations and have special vanes or other devices moves away f'rom the diver's mouth and the exhaled gas in them to captute the heat tiom the diver's exhaled brcath prevent exits the second stage through the exhaust valve. to help fr.ceze-up. These desigus are rccommended If the diver depresses the purge blrtton to expel water for divers rvho legularl-v conduct rvolk under the ice. from the second stage, this action pushes directll' on the RcgLLlatofs can be equipped with an additional sccond diaphragrt which actjvates thc lever and allows gas to flow stage. known as an "octopLrs" that can bc used to sup- ply air to an out-of-air diver (see through the second stage as long as the bunon is pushed. If in an cmergency Figure sand or other debris has accunrulated in the second stage, 5.19). This system eliminates the need for two divcls to or if the regulator is out of adjustment, the regulator mav sharc a single rnouthpiece and is usually compact atrd

Pllol

Orlfice

Alr to

Valve Seal

Air to -";;;.;;,;:iJ"'""'

Air from Flrst Stage

FIGURE 5.17 Downstream Second Staoe

5-lt, NOAA Diving Manual FIGURE 5,18 Adiustment Knob to Ease Diver's Breathing helps to streamline the diver. The additional second hose wlth the second stage can be purchased in a right or left configuration. This allows the second hose to be posi- tioned under either the diver's left or rieht arm.

5.3.1 Maintenance FIGURE 5.20 All regulators should be rinsed promptly with fresh, NOAA Technician Inspecting and Bepairing Regu- clean water at the end of each day of diving, pafticularly lators after exposure to salt water. The prefered method of per- forming this task is to have the regulator connected to the 5.4 EMERGENCY AIR SUPPLY cylinder with the pressure on. Water should be directed To cope with a complete loss of breathing gas, some over the first stage, the hose, and both inside and outside divers prefer to carry an independent breathing gas supply, ofthe second stage. complete with its own regulator. Special compact systems In the event that it is not possible rinse the regulator to are available with integrated regulators that hav€ been while it is connected and pressurized, it may be rinsed with designed for this purpose. Another option is to carry a the dust cap in place over the high-pressure filter on the first small (usually 13 cu. ft.) "bail-out" cylinder with its own stage. Failure to secure the dust cap in position prior to rins- regulator (see Figure 5.21). The size of the cylinder should ing will allow water to enter the first stage which can lead to be determined by the distance andlor time that separates corrosion. Similarly, if the regulator is not connected, is it the diver from a direct access to the surface. The cylinder essential to avoid pressing the purge button on the second may also be referred to as a "pony boftle" or "reserve gas stage while rinsing. Pressing the purge button will also allow breathing supply." water to flow back through the hose and enter the fiIst stage. NOAA requires that all their scuba regulators be inspect- 5.5 COMPRXSSED AIR ed and serviced by an authorized repair technician annually is the most frequently used diver's (see Figure 5.20). Regulators that are used daily will need to breathing medium. In its natural state at sea level pressure, be inspected and serviced more fiequently, as often as every compressed air consists of nitrogen, oxygen, argon, carbon quarter, depending on the environment and care. Prior to each dive, the diver should routinely do a predive inspection ofregulator,r\ hoses, mouthpieces, test breathitg, leaks, etc.

FIGURE 5.19 FIGURE 5,21 Octopus Regulators A Bail-Out Cylinder

Diver and Diving Supportff Equipment 5-l I dioxide, and trace amounts ofother gases. Table 5.2 shows breathing medium. When compressed air is purchased the natural composition ofair and pur ity srandards. from a manufacturel, it is essential that the gas is of high A11 ambient air does not meet the standards of purity puritv, free of oil contaminants, and suitable for breathing. necessary for use as a diver's breathing medium. For exam- It should be labeled "breathing air." Compressed air sus ple, in urban areas the carbon monoxide in pected of being contaminated should not be used for diving the air may be high, and in some cases it may reach a con- until tested and found safe. centration of 50-100 parts per million (ppm) (.005 - .01%). Proper identification and careiul handling of com- Ambient air may also contain dust, sulfur, oxides, and presscd gas cylinders are essential to safery. Compressed other impudties. These contaminants derive from industri- gas cvlinders used to transport gas under pressure are al sources and engine exhausts and must be avoided in the subJect to Department of Transportation (DOT) regula- breathing air supplied to a diver. tions. These regulatious include design, material, inspec- Scuba cylinders should not be filled from an ambient air' tion, and marking requirements. Compressed gas source when an air pollution alert is in effect. The Environ- cylinders can be extremely hazardous if mishandled and mental Protection Agency (EPA) monitors ozone and other should be stored securely in a rack, preferably in the oxidants in metropolitan areas, and the local EPA office upright position. should be consulted before a diving operatiorr is undertaken When in transit, cylinders should be secured from in an area suspected ofhaving high pollutant levels. rolling. Standing an unsecured cvlinder on end or allowing In addition to airborne pollutants, the air compressor it to roll unsecured could result in the explosive r upture of machinery and storage system themselves may introduce the cylinder. Cylinders can become deadly projectiles capa- contaminants, including lubricating oil and its vapor, into ble ofpenetrating a wall, and they can propel themselves at the breathing medium. Additjonally, the temperature of great speeds over long distances. the gas being compressed can be high enough at each suc- Scuba cylinders are often fitted with a n-rbber or plastic cessive stage to cause pyrolytic decomposition of anv that has holes in it to permit draining. These boots fit hydrocarbon compounds present. This is particularly true over the base of the cvlinder and help ro keep the cylinder if the compressor's interstage coolers are not functioning in an upright position. However, cylinders equipped with properly. Intercooler malfunction can be caused by exces- such boots should not be left unsecured in an upright posi- sive condensate, impaired cooling water circulation, or, tion, because the boot alone does not provide sufficient in the case of ail radiator coolers, by loss of cooling air protection against falling. flow caused by debris, dirt, or lint getting into the radiator fins. NOTE The free air intake of the compressor must be located Cylinder boots should be removed frequently and to drar.l air lrom an area where there arc no contaminants. the cylinder checked for evidence of corrosion. Potential contaminants include engine or ventilation exhaust, fumes or vapors from stored chemicals, fuel, or Compressed gas cylinders are protected against exces- paint, and excess moisture. sive overpressure by a rupture disk on the cylinder valve. No compressor should be allowed to operate wirh its Because regulators or gauges mav fail when a cylinder intake or first-stage suction blocked because this will pro- valve is opened to check the cvlindel pressure, it is impor- duce a vacuum within the cylinders that can rapidly tant to stand to the sidc rather than in the line of discharge draw lubricating oil or oil vapor from the compressor to avoid the blast effect in case of failure. crankcase into the air system. Some effective methods of preventing the intake of contaminated air are discussed WARNING below. DO NOT STAND IN THE LINE OF DISCHARGE WHEN OPENING A HIGH-PRESSURE CYLINDER. 5,5.1 General Safety Precautions There are three primary safety concerns associated If a cylinder valve is suspected of having a thread or with the use of compressed air or any compressed gas: seal leak, it should be completely discharged before any attempt is made to repail the leak. Leaks can sometimes be . Gas is sufficiently pure and appropriate for its detected bv painting a 20 percent detergent soap solution intended use (called "Snoop " ") over the external pafts of the valve with . Compressed gas cylinders or storage cylinders are a brush. Even small leaks will be obvious because they will properly labeled and handled cause a froth of bubbles to form. After the leak has been . Cylinders are protected from fire and other hazards repaired. the soap solution used for leak detection must be removed completely rvith fiesh watel and the valve dried Compressed air is available from many sources. Most carefully before reassembly. of it, however, is produced for jndustrial purposes and is, With th€ exception of scuba cylinders used fbr , therefore, not of the purity necessarv for use as a diver's scuba cylinders generall.v are not color-coded or labeled as

5-12 NOAA Diving Manual History of Diuing & NOAA Contributions

I.O GENERAL tiivers of Korea and Japan (see Figure 1.1) afe among tlrc I)ivers have penetratecl the occans throughout the cen- bcttcr-known breath hold divcrs. In his book, Htll NIilt turies fbr purposes identical to thosc of rnodern diving: ro Dorrr, William Be e be ( 1934) reports finding sevcral acquire fbod, search fbr treasLLre, canJ out military opera- rnother of pearl inlays in the course of conducting alt tions, perfbm scientific rcscalch and exploration, and enjo1, archcological dig at a Mcsopotamia site that dated back thc acluatic environment. ln a briel'histolv of cliving, Anhr.u' ru 4500 r.e. Thcse shclls rnu:r h,r\e been gatr'rlctl I'y Bachrach identified major plincipal pcr iods in the l.ristory of clivers and then fashioned into irlays by artisans of the diving: free (or bleath-hold) diving, bell diving. sur'face sup- period. Beebe also describes the extensive use ol pearl porl or helmet (hard-) diving, scuba diving, and satur.a- shells among people from other ancient cultures. The tion diving (Bachrach 1982). This chaptei also describes the Emperor of China. for example, received an oystel pearl formation ancl contributions of NOAA's Diving Ploglanr tr ibute around 2250 u.c. Frec divers u'ere also used in rnili- and the National Undersea Research Program. tary operations, as the Greek historian Thucydides r.eports. Dilers participated in an Athenian attack in which they cut l.t FRIE (BRXATH-HOLD) DTVTNG through under.water ban.iers that had been built to oLrstruct and damage the Greek ships. Frcc or breath-hold divers Free diving, or breath-hold diving, is the earliest of all sor.netin.res used leeds as breathing tubes, wl'rich diving tecl.rniques, and it has played a historic role in thc hollow allowecl them to remain subrrerged fbr longer periocls; this search for and treasure. The Hac-N1'u and pear.l type of primitive snorkel was uselul in rlilitary operations.

{-t:r'::S}: I.2 DryING BELLS '- J' Thc sccond principal histor ical mode of diving is bell diving. One of thc earliest repolts of the use ot a device that enabled a diver to er'rtcr thc water $-ith some degree of protection and a suppll, of air involved the Ctrl- iDtphtt used in Alexandcr the Creat s descent 1n appfoxl- nrately 330 e.c. Aristode describcd diving systems in use in his time: "They contrive a nreans of respiratiol tbr divers, ' lrv means of a container sent down to them: natural]y the container is not fllled with water. but air, \a,hich constar]tly assists the submerged man. ' In the 1500 ,vears firllorving this period, verv few developments occulred in cliving. It u,as not until 1535 that an Italian cleveloped a device that can be consiclered a true diving bell. This open bcll designed b1' Gugliclmo de Lorena actually workecl. A divcr worked tbr about an hour exploring the bottorn of Lake Nemi, Italy, for the prilpose oflocating Tlajarr's pleasure barges. Ir.t 1551, Nicholas Tafiaglia published an ingenious but inptactica' (see FIGUBE 1.1 ble design Figure 1.2) for a diving apparatus consid- Female Ama Diver ered to be an open bell. lt consisted ofa rvooden f|ame like l-I FIGURE 1.2 Open-Water Diving Bell (Circa 1551) that of a gigantic hour-glass to which a heavy weight was attached by a rope. A man standing in the frame, with his head enclosed jn a large glass ba1l, open onl-v at the bottom, was to wind himself down to the sea-floor b-v turnlng a windlass on which the rope was coiled. What he could do FIGURE 1.3 :5 ir hcn he got rhere nor r er1 c1car. Klingerl's Apparatus (Circa 1797) In 1691, the astronomer Sir Edmund Halley, then Sec- retary of, the Royal Society, built and patented a forerunner of the modern diving bell, which he later described in a repod to the Society. As Sir Edmund described it, the bell I.3 HELMET (HARD-HAT) DTVING was made of wood coated with lead, was approximately 60 Although these earll' divrng bells provided some protec- cubic feet (1.7 cubic meters) in volume, and had glass at the tion and an air supply, the_y limited the mobility of the diver. top to allow light to enteri there *as also a valve to vent the In the seventeenth and eighteenth centuries, a number of air and a barrel to provide replenished air. It has been devices were developed to provide air to divers and to afford thought that Halley undoubtedly knew ol a development greater mobiliry. For example, a German named Klingefi repoted by a physicist, , who in 1689 had pro- published in 1797 a design for a complete diving helmet and posed a plan to provide air from the surface to a diving bell dress (see Figure 1.3). The diving helmet obtained air by under pressure. Papin proposed to use pumps or be1- means of a twin breathing-pipe led into the helmet opposite low: to pror'de air and to matntain a consl

It NOAA Diving Manual still the most rvidely used commcrcial diving method. The use of mi-red gas and the devclopmcnt of improved decom pression tables have extended the diver's capability to wolk in thcse depths. Although surface-suppofted diving has sevcral advantages in tcrms of stability, gas supply, and lengrh of work period, a major problem with this type of gear is that rt severely limits rhe diver's mobility. This limitation has been overcome in celtain dive situations by the development of the self contained underu'ater breathirg apparatus (scuba).

I.4 SCUBA DI\TNG The dcvelopment of the sell-contained undcrwatef breathing apparatus (scuba) proviclcd thc free-movirrg diver with a portable air supply which, although flnite in com parison rvith thc unlimited ait sr,rpply available to the hel' met diver, allowed lcrr mobilitv. Scuba diving is the most liequentl)' usccl mode in and, in various ibrnrs, is also rvidely used to peffbrm underwater-work for n.rilitary, scientific, and comnercial purposes. There were many steps in the development of a suc- FIGURE 1,4 cessful seli--conrained underwatcr s1,stcm. In 1808, Frei- Earliest Functional Helmet (Circa 1823) derich von Driebcrg invented a bellorvs-in-a box device thar was worn on the diver's back and dehvered com- pressed air fr'om the surface. This device, named Tliton, Thc tirst major breakthrough in surfhce-support div- did not actually work, but it did scrve to suggest that c()ln' ing systems occurred with Augustus Siebc's invention of pressed air could be used in diving, an idea initialLy con- the diving dress in 1819. Around the same time. John ceived of by Halle_".' in 1716. In 1865, two Ffench and Charles Deane wcrc working on a design for a inventors. Rouqua-'-rol and Denaytouse. developed a sutt "smoke apparatus.' a suit that would allorv filefighters described as sclf-contained. In tact. their suit was not lu \'!rlrk r burnirrg buildings. Thel rLccived r pater'r Ior self-contained but consisted of a helmet using a surtace- this systcm in 1823, ancl later modifled ir to "Deane's supported system with an air rescrvoir that was carricd on Patent Diving Dress," consisting of a protective suit and the diver's back and was sufficient to provide one breathing a separate helmet with ports and hose connectrons for cycle on demand. The demand valve regulator was used surfacc-supplied air (see Figure 1.4). Siebe's diving dress u'ith surface suppl), largely because tanks of adequate consisted of a waist-length with a rrctal helnret strength \!ere not 1et available to handle air at high pres sealed to the collar. Divers received air under pressure sure. This system's demand valve, which rvas autornatical- from thc surface bv fbrce pump: the air subsequentl\r ly controlled, represented a major bleakthrough becausc it escapcd fieely at the diver''s waist. In 1837, Siebe modi- permitted the diver to have a brcath of air when necded in ficd this open dress. which allowed the air to cscape, into an emergency. the closed type of dress. The closed suit retalned the The demand valve played a critical part in the later attachcd helmet but. by vcnting the air via a valve. pro- development of one form of scuba apparatus. However, vided the diver rvith a lull-bodv air-tiglrt suit. This surt since divers using scuba gear exhaled directlv into the sut- servecl as the basis fi:r modern hard-hat diving gcar.. rounding watel, rnuch air was wastcd. One solution to this Siebe's was tested and tbund to be successful pr.oblem was advanced by Henry Flcuss, a merchatnt se;i- in 1839 when the British stafied the salvage ofthe ship man rvho inventcd a closed-circuit breathug apparatus 1n Rowl George at a depth oi 65 feet ( 19.8 meters). 1879 that used pure oxygen compressed to 450 psig, fbr the No major developrrents occurred in hard-hat gcar breathing gas suppl.v and caustic potash to purifl, the until the t\\,entieth ccntur_v, when mi-rcd bleathing gases. exhaled oxygcn. Although his rcbreather could be used heliurn-oxygen in particular, werc developed. The first under. cefiajn conditions. the depth limitations associatcd major open sea use of hclium and oxygen as a breathing with the use of pure ox),gcn dircctcd most attention to mixture occurred in the salvage ofthe subnrarine, U55 compressed air as a bleathing mixtr-rre. SrTrralls, in 1939. The bleathing of mixed gases such as ln the 1920s, a French naval oflicer. Captain Yves Le helium-oxygen pelmrtted divers to dive ro greater depths Prieur', begar rvork on a self-contained air diving apparatus for longer periods than had been possiblc u'ith air mix- thar resultecl ir thc arvard ofa patent in 1926. shared with tures. The surface-supported diving technique is probablr his countrYman Fernez. This clevice rvas a steel cvlinder

History of Diving & NOAA Contributions l-3 co::: : -.; --ompressed air that \vas worn on the diver's 1.5 SATURATIONDTVING ba:i :-: :-ad an air hose connected to a mouthpiece; the Although the development of surface-supplied diving J:. =: " r:: a nose clip and air-tight goggles that undoubted- permitted divers to spend a considerable amount of work- -.. .::: ::orective and an aid to vision, but did not permit ing time under water, divers using such systems for deep : -:i -:: iqualization. The major problem with Le Prieur's and/or long dives incurred a substantial decompression :::r-::-s rvas the lack of a demand valve, which necessi- obligation- The initial development of by -j::: : .-ontinuous flow, and thus a waste of gas. the U.S- Narry in the late 1950s and its extension by naval, --:. 1939, Dr. Christian Lambensen began the develop- civilian govemment, university, and commercial laborato- -:--.: oi a series of three parented forms of oxygen ries revolutionized scientific, commercial, and military div- :.::earhing equipment for under-water ing. This technique provided a method for divers to remain . . :rming, which became the first self-contained underwa- at pressures equivalent to depths of up to 2,000 feet (610 ::: rreathing apparatus successfully used by a large number mete6) for periods of days or weeks without incurring a --: divers. The Lambertsen Amphibious Respiratory Unit proportional decompression obligation. L-\RU) formed the basis for the establishment of U.S. mil- Divers operating in the saturation mode work out of a :rary self-contained diving. pressurized facilify, such as a diving bell, seafloor habitat, This apparatus was designated "scuba" by its users. or diver lock-out submersible. These subsea facilities are -{n equivalent self-contained apparatus was used by the maintained at the pressure of the depth at which the diver military of Italy and Great Britain during World will be working; this depth is termed the saturation or stor- War II and continues today. The rebreathing principle, age depth. rvhich avoids waste of gas supply, has been extended to The historical development of saturation diving include forms of scuba that allow the use of mixed gas depended both on technological and scientific advances. (nitrogen-oxygen or helium-oxygen mixtures) to rncrease Engineers developed the technology essential to support depth and duration beyond the practical limits of air or the saturated diver, and physiologists and other scientists pure oxygen breathing. dehned the respiratory and other physiological capabilities A major development in mobility in diving occurred and limits of this mode of diving. Many researchers played during the 1930s when French inventor, de Corlieu essential roles in the development of the saturation con- developed a set of swim fins, the first to be produced cept, but the U.S. Narry team working at the U.S. Subma- since Borelli designed a pan of claw-like fins in 1680. rine Medical Research Laboratory in New , When used with Le Prieur's tanks, goggles, and nose Coflnecticut, is generally given credit for making the major clip, de Carlieu's fins enabled divers to move horizontal- initial breakthrough in this field. This team was led by tlvo l)' through the water like true swimmers, instead of being U.S. Navy diving medical officers, George Bond and lowered vertically in a diving bell or in hard-hat gear. Robert Workman, who, in the period from the mid-1950s The later use of a singleJens face mask, which allowed to 1962, supervised the painstaking animal tests and volun- better visibility as well as pressure equalization, also teer human dives that provided the scientific evidence nec- increased the comfort and depth range of diving equip- essary ro confirm the validiry ofthe saruration concept. ment. In 1943, two other French inventors, Emile Gagnan 1.5.1 Satwation Diving Systems and Captain Jacques-Yves Cousteau, demonstrated their The earliest saturation dive performed in the open sea ''Aqua Lung." This apparatus used a demand intake was conducted by Edwin Link (founding father of Harbor r alve drawing from two or three cylinders, each contain- Branch Oceanographic Institution) and his associates and ing over 2,500 psi. Thus the demand regulator, invented involved the use of a diving bell for diving and for decom- over 70 years earlier and extensively used in aviation, pression. Initial Navy efforts involved placing a satura- came into use in a self-contained breathing apparatus that tion habitat on the seafloor. In 1964. Edwin Link. did not emit a wasteful flow of air during inhalation. This Christian Lambertsen, and James Lawrie developed the application made possible the development of modern first deck decompression chamber, which allowed divers open-circuit scuba gear. in a sealed bell to be locked into a pressurized environ- Scuba added a major working tool to the systems ment at the surface for the slow decompression from satu- available to divers; it allowed diyers greater freedom of ration. The first commercial application of this form of movement and required much less burdensome suppofi saturation diving took place on the Smith Mountain Dam equipment. Scuba also enriched the world of diving project in 1965 and involved the use of a personnel trans- bl permitting recreational dive6 to go beyond goggles and fer capsule. The techniques pioneered at Smith Mountain brearh-hold diving to more extended dives at greater have since become standard in opera- depths. tions; saturated divers live under pressure in the deck

t-4 NOAA Diving Manual decompression chamber on board a surface vessel, and (NMFS). A new NOAA component was created that are then transfered to the underwater worksite in a pres- formed a series of Environmental Research Laboratories. In surized personnel transfer chamber, also called a surface May 1971, these NOAA line offices met to develop opera- decompression chamber. Although saturation diving sys- tional and reporting requirements to promote safety and tems are the most widely used saturation systems ln com- establish . mercial diving today, two other diving technologies have A critical step to improve safety and versatility of also taken advantage of the principle of saturation, name- manned undersea operations was the 1971 establishment 1y, habitats and lock-out . ofthe Manned Undersea Science and Technology Program O4US&T) to achieve a better understanding, assessment, 1.5.2 Habitats and use of the marine environment. The major objectives Habitats are seafloor laboratories in which saturated included developing a NOAA civilian diving program as diver-scientists live and work under pressure for extended well as advanced ocean floor observatories and sub- periods of time. Habitat divers dive ftom the surface and mersible systems. The MUS&T Program assumed respon- enter the habitat, or they may be compressed in a pressure sibility for all NOAA diving activities including planning, vessel on the surface to the pressure of the habitat's storage administering, and overseeing the NOAA Diving Program depth and then be transferred to the habitat. Decompres- (NDP). Significant accomplishments included the estab- sion may take place on the seafloor or in a surface decom- lishment of NOAA's Diving Regulations, a pression chamber after the completion of the divers' work. Board, a Medical Review Board, and the preparation and The most famous and widely used habitat was NOAA's publication of the first edition of the NOAA Dtuing Manual Hydrolab whrch was based in the Bahamas and in 1975. A program was initiated in 1973 to develop tully from 1912 to 1985 and provided a base for more than 600 equipped field centers of diving expetise which included researchers from nine countries dudng that time. Hydrolab recompression chambers for emergency treatment and now resides at the NOAA campus in Silver Spring, Mary- medical training. land. The Aquarius, a more flexible and technologically Although the NOAA Diving Office was detached from advanced habitat system, has replaced the Hydrolab a.s the MUS&T program in 1979, the internal structure has NOAA's principal undersea research laboratory and rs been essentially unchanged. Present facilities include the presently deployed in the Florida Keys National Marine NOAA in Seattle, Washington, that has sever- Sanctuary. al recompression chambers and a 40,000 gallon controlled tank for equipment testing and training. Significant accom- 1.5.3 Lock-Out Submersibles plishments include the development ofa NOAA diver data- Lock-out submersibles provide an alternative method base to allow close monitoring of diver activity relating to for diver-scientists to gain access to the underwater envi- certification maintenance. A standardized equipment pro- ronment. Lock-out submersibles are dual-purpose vehrcles gram integrated with this diver database has resulted in dra- that permit the submersible's pilot and crew to remain at matic cost savings and improved quality contol and safety. surface pressure, while the diver-scientist is pressurized in Other significant developments included diving safety, a separate compartment to the pressure of the depth at physiology, and biomedical programs with the U.S. Narry, which he or she will be working. The lock-out compart- underwater fatality statistics studies and accident response ment thus serves as a personnel transfer capsule, transport- programs, polluted water diving research, and hot water ing the diver to and from the seafloor. Lock-out diving studies. A major innovation by NOAA was the submersibles have seen limited use since the 1980s. 1977 introduction of nitrogen-oxygen (nitrox) breathing mixtures and decompression tables to the diving communl- I.6 NOAA'S DI\'ING PROGRAM ty. Nitrox maximizes bottom time for scuba diving investl- For over 40 years, NOAA and its predecessors have gators. The NDP also developed a system for preparing played a significant role in the development and suppofi of nitrox in the held. scientifrc diving. Prior to the formation of NOAA in 1970, The NOAA Diving Progran plays a critical role in the most of the non-defense dive activities centered in the development and support of for NOAA United States Coast and Geodetic Suwey (C&GS) and the and the United States. NOAA has more than 300 divers at Department of Intedor's Bureau of Commercial Fisheries 40 locations and on 14 ships and has the largest comple- (BCF). ment of divers of any civilian government agency. Averag- When NOAA was fomed in October 1970, the C&GS ing 10,000 dives annua1ly, its exemplary safety record is and BCF became two of NOAA's major line components attdbuted to thorough training, adherence to established with C&GS renamed the National Ocean Service and the standards and procedures, and the use of quality, well- BCF became the National Marine Fisheries Service maintained equiDment.

History of Diving & NOAA Contributions t-5 I.7 UNDERSEA A}[D DIVING RESEARCH nearly 8,000 air, nitrox, and mixed-gas scuba dives The creation of what is now known as the National addressing issues relating to ecosystem health, coastal Undersea Research Program (NURP) was initiated with processes, and frsheries. programs the 1977 genesis ofNOAA's Undersea Laboratory System NOAA has traditionally sponsored R&D to (NULS), under the Manned Undersea Science and Tech- improve diver performance. Dive tables and training requirements developed by these programs are now wo d- nology MUS&T) Program, to provide staffed underwater facilities and other research support. Later that year, wide standards. NOAA is the only federal program with NULS deployed an undersea research habitat, Hydrolab, statutory responsibility to improve the safety and perfor- to allow science missions off St. Croix, Virgin Island. mance of divers. Examples of NOAA's diving research In 1980, the MUS&T offrce was reorganized under program include fundamental hyperbaric physiological NOAA's Offirce of Undersea Research and became the research, operational procedures, safety, medical aspects, Office of Undersea Research (OUR) which evolved into environmental impacts on divers, technology development, NURP. At present, NURP supports extramural research and data dissemination. Active international programs programs through scientists from marine and academic include the U.S.-Japan Cooperative Program on National institutes carried out primarily through six National Resources (UJNR) Panel on Diving Physiology and Tech- Undersea Research Centers, nology and the U.S../France Cooperatiye Program of NURP is a comprehensive underwater research pro- . gram that places scientists under water directly, through the use of submersibles, underwater laboratories, and r.8 SUMMARY scuba diving, or indirectly by using remotely operated vehi- Humans have explbred the ocean depths at Ieast since cles (ROVs) and observatories. The tfl situ (in place) the fifth millennium 8.c., and the development ofthe div- approach allows acquisition of otherwise unobtainable ing techniques and systems described in this section observations, samples, and experimentation related to reflects a human drive for mastery over all aspects of the NOAA priority research objectives such as building sus- environment. The search for methods that will allow tainable fisheries and sustaining healthy coasts. NURP humans to live comfortably in the marine biosphere for also provides access for the United States research commu- long periods of time continues today, as engineers and sci- nity to civilian, military, and intemational undersea tech- entists work together to make access to the sea safer, easi- nology. In the past decade, NURP has annually supported er, and more economical.

t-6 NOAA Diving Manual would include a biologist, a chemist, a HAZ-MAT sp€cial- After evaluating actual and potential contaminants in the ist, and a intimately familiar with process, three options are avai.lable: appropriate diving equipment and procedures. As a minimum, polluted-water diving training should 1. Diving is not an option when unacceptable expo- include the following topics along with hands-on and in- sure conditions exist or when the water contains water scenarios: chemicals in which a diver should never be allowed to operate. In this case, other means (i.e., remotely . recognition and evaluation operated vehicles, surface sampling devices, etc.) . GolNo-Go decision making must be used to obtain required data. . Equipment selection 2. For less severe but still hazardous exposures where . Dive planning it is absolutely necessary to have a diver enter the . Dress-in procedures water, total encapsulation (i,e., full-coverage hel- . met mated to a dry suit with dry gloves) should be . Emergency procedures required. . Postdivedecontamination 3. In less polluted environments (i.e., where contarni- nants are bound to sediments or the waters carry low levels of biological contamination) a full-face 13.3 EQIJIPMENT mask can often be used with a dry suit and dry gloves. This system offers a lesser degree ofprotec- 13.3.1 General tion than a helmet but far more protection than a Polluted-water diving specialized operations require half mask with scuba regulator. equipment. Both the dive6 in the water and the support personnel properly topside must be equipped. Although 13.3.2 Full-Face Masks equipment used topside is essentially the same as that used Full-face masks can be supplied with breathing gas personnel by for HAZ-MAT operations, special considera- from a variety of sources including open-circuit scuba, sur- tion must be given to splash-back protection and the face-supplied systems, or a . When used in the amount of water required to decontaminate the divers. open circuit mode, full-face masks should be equipped with Equipment used for polluted-water diving is somewhat dif- a sedes non-return valve to prevent a backflow of contami- ferent from standard "off the shelf" scuba or surface-sup- nants into the breathing system- In addition, the mask plied diving equipment. should have separate inhalation and exhalation chambers. There are several characteristics of commonly used This will help to further reduce the possibility of inhaling a diving equipment that make it unacceptable for diving in spray of contaminants ifleakage occurs on the exhaust side contaminated water: foam neoprene dry suits are difFrcult of the breathing system. to impossible to adequately decontaminate; the numer- Since a full-face mask can leak if a strap breaks or ous "breakable" seals on masks, helmets, and suits becomes loose, another desirable feature is a positive pres- increase potential for leaks; and reliable, dry-glove sure regulator. Scuba full-face masks normally operate in arrangements are scarce. Moreover, exhaust valves in the demand mode, but masks with positive pressure are demand regulators allow a few small droplets of water to designed to free flow if the face seal is broken. This very enter during the exhaust cycle. When the demand valve important feature can help prevent contaminants from is activated during inhalation, the jet of incoming air entering the mask in the event of a leak. Positive pressure breaks up the droplets into a mist which is then inhaled masks also clear water automatically if the mask complete- by the diver. ly floods. Conservative calculation of breathing gas supply It is essential to keep in mind that accidents which requirements is absolutely essential when using full-face occur when diving in polluted water may require addition- masks with open-circuit scuba equipment. Unforrunately, al procedures prior to initiating standard diving accident buoyancy can be a problem with some full-face masks. management. The combination of top-quality, well-main- Depending on the individual, some masks with high inter- tained equipment, coupled with proper training, safety con- nal volumes may be buoyant producing jaw fatigue and sciousness, and common sense can go a long way to generally making the mask uncomfortable to wear. Select- reduce the likelihood of accidents. There is no such thing ing a mask with the lowest volume available is advisable, as 100 percent sale contaminared-water diving. assuming it meets the other important criteria for the spe- Just as there are different levels of protection for HAZ- cific polluted-water application (see Figure 13.2). MAT situations topside, there are different rypes of diving It is possible to use a full-face mask with a fully closed- equipment to be selected according to the hazard level circuit rebreather, however, the cost involved with purchas- under water. Unfortunately, no standards cu[ently exist ing and maintaining the system, plus the additional for diving equipment that can be selected based upon the training requirements for personnel, may make the use of potential effects/risks of the hazard to the divers. such systems for polluted-water application prohibitive.

Polluted-Water Diving r3-5 llg tl Reclaim system R ll:l ?

veuumPunp I vaculnPlmp

FIGURE 13.2 Full-Face Masks for Use in Contaminated Water

13.3.3 Diving Helmets For exposure to chemical or biological hazards that can produce severe illness or death, divers should be equipped with a full coverage helmet, a dry suit with a mating yoke FIGURE 13.3 for the helmet, and mating dry gloves. The advantage of a Schematic of Reclaim System with Topside Supply diving helmet over a full-face mask is that the diver's entire head is encapsulated in a dry environment. Diving helmets are also less likely to be accidentally pulled-off a diver's head and they are less prone to leak. (see Figure 13.4). The SEV helps prevent a back-flow of The typical mode for supplying breathing gas to a fuIl- water into the helmet. Both the regulator exhaust and the coverage helmet is from a surface-supplied source. Such main helmet exhaust are linked together with a special tube, sources consist of either a low-pressure arr compressor or a and a third extemal exhaust valve is added to the system. high-pressure gas stonge system that is reduced to low pres- Any water that manages to sneak past this outer exhaust sure. Another, more sophisticated mode of supplying gas to valve is unlikely to make it past either of the two other a diving helmet is a "reclaim" gas system. A reclaim system, valves. Testing by NOAA using dye tracers revealed the pres- also refered to as a "push-pull" system, routes the helmet's ence of occasional droplets of water behind the outer-most exhaust to the suface, by means of a separate hose, where tt valve, however, none were detected inside the second valve. is either recycled or exhausted to the suffounding atmos- phere (see Figure 13.3). The advantage ofthis type ofsystem 13.3.4 Umbilicals is that it reduces the possibility of contaminants enterirg the One of the big problems with umbilicals for surface- helmet via a back-flow through the exhaust valve (see Figure supplied diving in the past has been that they have tradi- 13.4), and protects the tender from volatile contaminants tionally been assembled with duct tape, which can absorb being released from the sediment and transported to the sur- contaminants or even disintegrate when used in contami- face with exhaust bubbles. The disadvantage is that they are nated water. New umbilicals are available today made more expensive and not easily deployed on a sma1l boat. from chemically resistant hoses that are manufactured in Special reclaim systems have been developed specihcally for a spiral and require no tape to hold the components pollured water diving ( Di\ ex lqqT' together (see Figure 13.5). These are preferred for many Diving helrnets that are equipped with demand regula- polluted-water diving scenarios. tors, without reclaim systems, are subject to the same exhaust "splash-back"problems experienced with open-cir- 13.3.5 Dry Suits cuit scuba regulato$. To reduce the possibility of this hap- If a dry suit is to be used with a full-face mask, the dry pening, NOAA developed the "series exhaust va1ve" (SEV) suit must be equipped with a latex or vulcanized rubber t3-6 NOAA Divine Manual NOAA NO.DECOMPRESSION AIR DIVE TABLE CHART 1 - DIVE TIMES WITH END.OF-DIVE GROUP LETTER Naxruuur DtvE rlME RtoutBtNG DEcoMPREsstoN L!q,l EvEN CoMPLTANCE WITHTHESE DEPTH 6fl WAFNING: SIRTCT uo-stoc MINUTES BEoulRl-D AT 10lsw sl0P {3prs'v) CNARTS WLL NOT G UAFANTEE AVOIDANCE OF f{! rtvt I[ DECOMPFESS ON SICKNESS CONSEFVATIVE USAGE S STFONGLY RECOITTMENDEo 12 40> 15 25 30 40 50 70 80 100 110 130 150 17C ,3 50> 10 IJ 25 2n 40 50 60 70 80 90 rodHii RNT -'t. "..,orot ^,r"oe." + ABT rcruer eorov r ue 18 60> 10 t3 20 25 30 40 50 55 gg*{-+|ifr" ES DT .o,uore"t s'^n.. o,u. 22 70> 10 15 20 30 35 40 45 cu/ItrL-tl (USE ESDTTO 50t60 70 OETEBMINE 40 END.OF.OVE 25 80> 10 tc 20 25 30 35 60 28 e0> 10 t1 tc 20 25 30 ;f 40 31 100> 5 7 10 tc 20 22 ?! 23 30 34 110> 5 10 13 tc ?q , 37 120> 5 10 12 t3 , 40 130> I ioXi A B c D E F G H I J K L M N

40 50 60 70 80 90 100 110 120 130

6 5 4 3 3 3 3 3 12r00 l2:00 l2:00 l2:00 l2:00 12r00 12:00 12:lto l2:01, 12:l,O l2:00 t2{o 12:llit 193 94 46 36 27 1T 7

11 13 9 s 6 3:20 4:49 sr48 6r34 7:05 7:35 7r59 a:21 8:50 8:58 9t2g 9r43 2:39 3:25 3:58 4t26 4:50 5t3 5r4l 5:49 6:Og 6t9 6:33 163 a7 49 4t 32 23 18

NOAA Diving Manual III-l 7 .2 .2 .l Qralification Test NOAA nitrox trainees attend classroom sessions and To pass the qualification test, candidates must demon- then progress to open-water dives. In order to receive the strate the ability to: NOAA Nrtrox Cenification. srudenls must pass a wrirten examination and complete two open-water dives using . Plan and organize a surface-supplied air dive nitrox breathing mixtures. operation . Demonstrate ability to rig all surface and underwater 7.2.4 Saturation Training equipment properly, including air supply systems, This section introduces the basic components of train- mask./helmet, communications, and other support ing for saturation dives. See Chapter 17, Diving From equipment Seafloor Habitats, for practices and procedures related to . Demonstrate proper procedures ofdressing and satuation diving. undressing a diver, using the particular pieces of Although the basic requirements for saturation diving equipment needed for the working dive are the same as those for surface-based diving, there are . Tend a surface-supplied diver some important differences that need to be addressed dudng . Demonstrate knowledge of the following emergency training. The diver's "home base" dudng satwation usually procedures: loss of voice communications, flooded is either a seafloor habitat or a diving bell system. For this masks and helmets, and entanglement reason. the satumtion diver needs a fundamental reorienta- . Participate in at least two practice dives, as tion to his new . For example, the described below: saturation diver must constantly be aware that he cannot - Properly enter water that is at least ten feet (3 m) retum to the surface in an emergency situation. This factor deep and remain submerged for at least 30 minutes, has specifrc implications with respect to the selection and demonstrating control ofair flow, buoyancy, use of certain pieces of satumtion diving equipment. Satura- mobility, and familiarity with communication tion diying has special requirements including: systems Ascend and leave water in a prescribed manner Redundant air delivery systems: - Properly enter water that is between 30 and 50 feet - These consist of double steel or aluminum cylinde$ (9.1 and 15.2 m) deep and conduct work-related using a manifold valve system with isolation capa- training tasks bility, allowing the isolation of each cylinder in case of a critical equipment failure, such as an extruded After successful completion of this test, the instructor neck o-ring or blown 'burst disc'. The use of should evaluate the diver's performance and establish a rylirrder steel cylinde$ (as opposed to aluminurn) also elimi- phased depth-limited diving schedule to ensure a safe, (i.e., gradual exposure to deeper working depths. Detailed nates the need for a separate weight system descriptions of umbilical diving equipment and its use weight belt). The use of weight belts dudng satura- potential point appear in Chapters 5 and 6. tion diving adds an unnecessary of failure. The sudden unexpected loss of ballast could result in an uncontrollable ascent to the surface. 7.2.3 Nitrox Training The utilization of a redundant regulator system Nitrox diving involves the use of a nitrogen-oxygen (two separate fiIst and second stage regulators) pro- breathing mixture containing a higher fiaction of oxygen vides an alternative regulator system in case of a than norrnally found in air. complete failure of the diver's primary regulator. The cur:riculum for NOAA's Nitrox Training Program The use of redundant pressure gauges (cylinder includes coverage ofthe [ollowing topics: - pressure) allows the monitoring of pressure within each individual cylinder, should isolation of the . NOAA oxygen limits manifold be necessary. . NOAA NN32 and NN36 breathing mlrrures (cave when . Depth/time limits for oxygen during working dives Line reels or safety reels) must be used . Central nervous system and pulmonary divers are working away from the excursion lines . Analysis of ninox breathJng mixrures (lines leading directly to the habitat). The inability to . Nitrox dlrlng equipmenr (open-circuit systems) find one's way back to the habitat would constitute . concept and calculation an emergency situation, since divers do not have the . NOAA NN32 and NN36 decompression tables luxury of ascending to the sudace to reorient them- . Safe handling of oxygen selves relative to the habitat location. Intuoduction to gas mixing techniques Surface marker buoys (SMB) are used to mark either Oxygen equipment cleaning a surfaced diver or lost diver at depth.

Diver and Support Personnel Training 7-7