safety in oil tankers

8/2/2019 Safety in Oil Tankers

1/27


2/27

First Published in 1973byInternational Chamber of Shipping

Reprinted 1973, 1974, 1977Revised 1978

Reprinted 1979, 1982, 1990, 1992 International Chamber of Shipping, London

Printed & Distributed by:Witherby & Co. l.td.,

32/36 Aylesbury Street,London EC1R OET , England.TeL No. + 44 71 251 5341Fax. No. + 44 71 251 1296


3/27

D anger can alw ays be presen t in a tanker.Most of the risk is removed by the designer.W hat risk remains ca n only b e a vo id ed by tak ing care .This care must be taken by everybody aboard the ship.You.To be able to avoid risks you mus t know what they are.This booklet warns you of the risks.It explains how they can arise.It instructs how they can be avoided.By you.

II!

T erm s are ex plain ed a s we go along .If you already understand the terms, please be patient-yourshipmate may not.

In this booklet petroleum means crude oil or products made from it~Petroleum can be handled safely.

Care is absolutely necessary-throughout the whole operation.

Published in 1973 and revised In 1978 byTHE INTERNATIONALCHAMBER OF SHIPPING30/32 St. Mary Axe, London EC3A 8ET

To be able to exercise care you need to know something about petroleum.T he characteristics of an y substance which determ ine how it will behave under

various conditions are known as the properties of the substance.W e shall deal w ith som e of the properties of petro leum .

You ought to know these.

page one


4/27

VapourAll liquids can change - o r be changed - into vapour. T he process ofchanging into vapour is called evaporation. It is usual to refer to suchvapours a s g as es. P etro te um forms petroleum vapour

Evaporation

Burning Liquid petroleum does not burn. It is petroleum vapour that burns.Danger increases according to how readily a product evaporates. Thelow er the tem perature at w hich a petro leum can evapora te , the m oredangerous it is.

Mixtures A petroleum vapour can only burn if it is mixed with oxygen. Oxygenis an important part of the air around us. W hen we refer to a mixturein this booklet we norm ally m ean a mixture of pet roleum vapour an d air.

F lammab le You will recognise the word flame in flammable. F lammab le meanscapable of being set on fire. A m ixture w hich can be set on fire is aflam mable m ixture.

F lammab leLimits

It is possib le to have a m ixture containing so little or so m uch petroleumvapour that it cannot burn. M ixtures that have reached these s t rengths ,.have reached the flam mab le limits.

F lammab leRange

Be tween th es e fla mma ble tirnits there lies a quite narrow range ofm ixtures which are flam mab le.T his is know n as the flamm able range .Flammable limits and flam m ab le range are som etim es referred to as th eexplosive limits an d explosive range.

page two


5/27

Most substances when heated expand.E vaporation causes rapid expansion .Burning of the vapour causes heating and even greater expansion.If the expansion is confined pressure m ay increase still further . ~ .

. . . EXPLOSIONFlash poi nt The lowest temperature at which a liquid gives off enough vapour to

form a flamm able m ixture is called its fla sh p oin t.Some products evaporate very rapidly. They produce plenty of gas atnorm al pressures and tem peratures. G asoline is an obvious exam ple.Vapour is nearly always present. A hot enough spark w ill set it on fire.A word we shalf use instead of se t on fire is ignite.

Volati le L iquids w hich evapora te readily are known a s vo la ti le liquids. Anypetroleu m with a fl ash poi nt below 60 C (140

0

F) is classed as volatile.Spent refinery w aste - spen t caustic soda for exam ple - may containvolatile petroleum.

Non-volatile Som e other petroleu m evapora tes less rapidly. T hose w ith a flash po intof 60C (140F) or over are classed as non-volatile. G as oil and dieseJoil are two examples .

Petroleum mist Petro leum sprayed from a leaking pum p or p ipe m ay form a m ist ofdroplets .

.. page three


6/27

III,

-~-,--~-I~I-~--~- _ . = L_ _~

-._---

If a cigarette lighter falls, it may operate.

page four

F l ammab l e mixtures may b e w here you least expect them . They areeas i Iy ig n ited ~Sparks can set th em off. ~

Smoking Sm ok ing can be very dange rous .Secret smoking is more dangerous th an contro lled sm okinq .The re may be f lammable gas in a to ile t (for instance). G as m ay havebeen drawn into the ventilation sy stem . A crafty sm oke could bedisas trous ,

Smok i ngin bed

Smoking in bed is foolish anywhe re . It is dangerous in any ship.It ca n be disastrous in a tanker .

Lighters If a c igare t te lighter falls it may operate.M atches Non -safe ty m atches are a m enace .

Even safe ty matches m ay Iight accidently.Torches Ordinary h an d to rch es (f f ashliqhts) spark.

Domesticequipment

'CDomestic equipment which can ignite flammable vapours include -e shavers- rad ios- electric cooking appl iances


7/27

O bey ALL instructions about smoking.The captain will sa y where smoking is allowed.ONLY SMOKE WHERE SMOKING IS ALLOWED.

In some ports the local authorities prohibit smoking anywhere in theship. There are heavy penalties for breaches of these regulations.

NEVER SMOKE IN BED . - .. . "

1 ., -- ~ f " " , - . - - .. , .. . , ,) . 8 ~ I .: i ! ! : . , ; i i l i j t j ; I . : ; - : : : ' : (: :~ i : : : .If you are allowed a cigarette lighter on boarde keep it in your cabinKeep non-safe ty matches away from tankers .K eep all m atches away from areas where you are not a llow ed to sm oke.

Use only special torches (f l ashliqhts] issued on board.Keep your electric shaver and radio in your cabin.

If there is any possibility of flammable vapour entering galleys oraccommodation -e do not use electrical appliances

Never smoke in bed!

page five


8/27

Aluminium If aluminium or one of its alloys is knocked against rust there may be aflash of heat. The heat can be enough to ignite a f lammable mixture.

Aluminiumpaint

Aluminium pain t over rust may be just as dangerous.If that is struck or rubbed the same heat may be qener ated.

Rubbish Dirty waste , rags, sawdust and other rubbish is dangerous if leftlying about.Heat may be generated within bundles o f r ub bis h.The heat may be enough to ignite flammable mixtures.It may become hot enough to set itself on fire.T he risk is increased if m ateria l is left near steam pipes.

Cathodicprotection

Some ships tanks are fitted with ca thodic pro tec tion . T his is a m ethodof controlling corrosion. Metal slabs known as anodes are fitted intotanks. They are on supports. If an anode or its support is struck ordislodged a spark m ay result.

Electrictools

E lectric tools and appl iances used in tan k clean ing and gas free ing ca nproduce sparks - \,e if they are not of approved designe if they a re d ef ec tiv e

Tools Metal hand tools cou Id cause sparks by - striking togethere striking against other metal- being dropped"Non-spar k inq ' tools could be hazardous as ferrous m etals m ightbecome embedded in the material .

Metal tools could cause sparks bv beingdropped.

..naqe SIX


9/27

a\urfl\f\iurfl pa\nt.Never use a\urfl\f\iul11 paint \f\ - .

cargo tanks pump rooms

a\urfl\n\um or a\um\n\Um a\\oYC\ear awaY a\\ waste, rags, sawdust etc. atter

use.Never knock anodes or their supports \n tanks.

use of\\Y approved type. report anY detects in this eC\U\pment

\n any area where there may be e)(.p\QS\ve"apour - prevent meta\ hand too\s horn knoc\(ing tOgether prevent rneta\ hand too\s trorn being dropped do not use sO caHed IInon-sparking" too\s

Lower steel hand tools in a canvas bag

page seven


10/27

Staticelectricity

Static electricity is generated within tanks in several ways -e when filling with clean oil productsetit

when w ashing w ith w ater jetsw hen steam ing a tank ~The product or water mist or steam becomes charged with electricitv.

The charge will try to discharge to earth. In t ime it will dischargeitself harmlessly through the ship's hull.While sufficient charge rem ains a hot spark ~ capable of igniting aflammable m ixture - m ay b e p ro du ce d. There ar e several ways in whichthis might happen involving th e introduction of m eta l o bjec ts intoa ta nk.O bjects w hich have caused sparks include -e hand-held m eta l ullage tapeseee

m eta l sam ple cansme ta I sou nd ing rodsungrou nded portable wash ing mach ines

A sta tic charge - and spark - may also be caused by carbon dioxide orsteam being discharged at a high rate from a n oz zle .

~Tankwashing

Flammable gas remains in a tank after it i s d ischarged .This presents a hazard ~ particularly during washing ~ unlessappropriate steps are taken.

NO!...

page eight


11/27

A ma te ri al which conducts electricity is known as a conductivematerial or a conductor.

\A !h en a petroleum which is above it s flash point is being loaded intogas-free tanks the following must be made of non-conductivem aterial -e hand-held ullage tapese u rla ge stick stit sam pfin g co ntain ers

wait until machines have been removed from the tank.

At least th irty m inutes m ust elapse after completion of loading beforehand-he 1d me tal or othe r co nd u ctive equ ipment m ay be used.An officer will authorise the operation of fixed carbon dioxide or steamfrrefighting equipment.W hen tank w ashing is in progress - keep tank openings closed as m uch as possiblee do not introduce metal objects into the tank, other than a grounded

w ashing m achinedo not disconnect tank cleaning hoses from their hydrants untilthey have been removed from the tank

.page nine


12/27

Toxicity Fire is the best-known danger in tankers. T here is another risk w ithpetroleum: toxicity.Toxicity is the ability of a substance to harm you if it reaches a sensitivepart of your body. A substance that does this is toxic.

Effects ofVapour

Petroleum vapours are tox ic. B reathe them and they harm v ou , Evensmall quantities can -e dull your sense of sm ell- .e- -

make you dizzyproduce a diminished sense of resp on sib il itygive you a head ache

e irritate your eyesThe dizziness and loss of responsibility are rather like drunkenness .Your speech m ay become slurred.Increased qu a nt i ties will lead to ~It staggering_ confusiontit loss of consc iousnessL ar ge q ua nti tie s m ay result in -e arrest of b reath inge arrest of hearte death

VI/aging or sampling the WRONG way

page ten


13/27

Do not inhale petroleum vapour.~j

When ullaging or sam pling -_ face across the wind-. close atl ta nk o pe ning s a s soon as you finish

____%

It may be necessary fo r you to keep a w atch on a m an tak ing u llaqes .You m ay have to w ear breathing apparatus w hen u lla gin g c er ta incargoes . , ; 1\ . - .

. . I ~ . .I ...\. ._. . .responsib le o fficer m ust ensure that it is safe fo r you to enter an y1enclosed space by -- --_-.----testing the atmosphere; orspeci fy ing the Iife -s us ta in ing equ ipm ent you m ust wear; andta kin g all n ec essary precautions for you r safety o r escape

Thi s appl ies to -_ ca rgo tan ksIt pump roomstit holds used for carrying packed petroleumand of course to other enclosed spaces, such as -e double bottoms__ cofferdams_ peak tanks

. _ _----___.- - -. --L

Ventilation must be continuous while you work in packed-cargo holds.If ventilation or work is interrupted, regard the space as unsafe.

IIII

- - - -- -

VI/aging or sampling the RIGHT vtlay .facing across the wind.

page eleven


14/27

Never rely on your nose.

page twelve

Rotten eggs I n som e petroleum there is a dangerous gas called hydrogen su lph ide .T his sm ells of rotten eggs. It quickly dulls you r sense of sm ell. F irst yousme l l it then you don't . You may suppose it is no longer presen t. T hismay not be the c a s e ABecause they dull your sense of smell petroleum vapours ar e doublydanqerous. If you cannot sm ell them you m ay think they ar e notpresen t. You certainly cannot judge how much there is.The absence of smel l does not mean the absence of petroleum vapour.We have said that some of the ill effects of breathing petroleum gas area bit like drunkenness. You will know some people who can hold theirliquor. They seem to be able to drink a lot without showing any signs ofit. That does not mean that the stuff in the bottle is any lesspotent

Tolerance of Som e people can to lera te pe tro leum vapours better than others. You,vapour or somebody you are watching, may be one. You may not show or feel

early ill-effects, You m ay th ink the atm osphere is safe ABut -e there may b e d an g er ou s v ap ou r pre se nt_ it m ay be a flammable mixture_ the atmosphere may be tox ic

Re sp i r at or s Anti-gas respirators - such as the military type - into which air is drawnthrough absorbents , afford you no protection agains t atmospheresdeficient in oxygen and mus t no t be u sed in enclosed spaces .


15/27

Never w ait until i f j . . effects w arn you tha t pe tro leum vapour ispresent.Never rely on see ing ill-e ffec ts in others as a w arn ing tha t petro leumvapour is present.

PROTECTIVE CLOTHINGProtective clothing is often necessary. It protects you from possibleharm . It may simply be gloves o r gogg les. It cou ld be necessary for youto w ear a com plete su it w ith a helm et.Your officers will know which cargoes can harm YOUa They know whatprotective clothing you m ust w ear.Follow your officers' instructions -_ wear w hatever pro tec tive clothinq you ar e told to weare wear it whenever you are told to do so

-,1. ,I

, f' .. t]r ~ -, ~~ '- ':

Protective cloth ing shou td be kept clean and dry. Protective cloth ingmade of heat-resistant material w ill in time abso rb and transm it heat.Damp clothing of this type can scald you when it is exposed to fire.There is nothing cowardly or childish in wearing protective clothing.It is n ot brave to leave off necessary protective clothing. It is foolhardyto leave it off.It is unsafe to be foolhardy.Wh en n ec essa ry you w ill be issued w ith special breath ing apparatus. U seonly the correc t gear. Do not improvise or use makeshif ts . Breathing apparatus end protective clothing.

page thirteen


16/27

Petroleum~mist

Petroleum m ists or spray can be harm ful.If you inhale them in large quantities they can irritate your lungs.This irritation can lead to pneumonia.

Skincontact

Petroleum can dam age your skin .Light petroleum-kerosene for example-scan cause dermati t is . Heavierpetro leum can block your pores and cause a rash . You may hear thisrash referred to as oil sene.Some heavy petroleurn+lubr icatinq oil for instance-can producemore serious long-term effects. In contact with the skin over longper iods they m ay cause sk in cancer. T here is particular risk of cancerof the scrotum.Petroleum-soaked underctothes are obviously dangerous.

Lead Lead com pounds are added to som e petro leum s. Ships' tanks canbecom e contam inated by these. Consecutive voyages carry ing suchcargoes ca n dangerously conta m inate a tan k .

. .porsonmq

Reducedoxygen

Your bra in has to have an adequate supply of oxygen. T he oxygencontent of the a ir in a tank can become reduced.Oxygen reduction is particularly likely ~e after inert gas, steam , or carbon dioxide has been used-- in an y unventilated spaces

Dermatitis. CarbondioxideCarbon dioxide is much heavier than air. It will naturally linger inspaces into which it is injected.

pagefourteen


17/27

If petroleum gets on to your skin -_ rem ove it as quick ly as possib le_ use soap and w ater or a specially p rep ared clean sere do not use harsh soaps~they may c au se d er m ati tisIf you use waste or rags to rem ove splashes -e change them frequentlye do not keep them in your pocketWear clean work cloth es w hen ev er poss ible=-par ticularlv underc lothes .

c'Shower at th e en d of each day's work. Remove all traces of oil fromyour skin.When working in tanks w hich have contained le ad ed p etr ole um forconsecut ive voyages -_ wear full protective clothing_ do not inha le an y vapourse avoid con tact be tw een your sk in and any scale or s ludge_ rem ove im m edia te ly any sca le or sludge which touches your skin_ wash the contaminated skin w ith to ts of soap and w atere maintain ventilationAfter carbon-dioxide extinguishers have been used in an y confined orpartially confined spaces -e only enter under an officer's supervisionIt only enter w earing breathing apparatus and a life line Remove petroleum from your skin asquickly as possible.

page fifteen


18/27

Gas may be released when loose scale isdisturbed.

Presence ofg a s

The re m ay be f lammable gas --- - after loading or discharging volatile petroleumafter loading non-volati Ie petroleu m into a tank wh ich is notPressure

gas-freeIt may be in th e tan k: it may be at an y open ing to the t ank .Vapour in tanks may be under pressure

In spacesdeclaredgas-free

Fu rther gas may be re leased ---It after loose scale or sludge i s d i st u rbe de af te r a heating co il is opened up- w hen a p ipel ine or valve is opened up- when a cargo pump or valve is opened up-- when a cargo vent line is opened up

lin otherspaces F lam mable gas m ay be in any space in to w h ich vola tile pe tro leumcould have leaked . E xam p les are -e pumproomse cof f e rdamse ba llast tan ks_ empty compartments next to tanks used to carry low flash

point petroleum

GAS-FREE A space declared gas-free is free of gas a t the tim e o f the test. T hespace may n ot rem ain gas-free . Remember: further gas may be released.T he absence of flam mable m ix tures does not necessarily m ean thespace is gas-free and safe . Remember toxic gases are not necessarilyflammable.


19/27

Before you open a tank any pressure m ust be re lieved .T h is has to be done very carefu lly ~ under con tro lled conditions .O pen ings m ust be closed as soon as possib le.

A space w h ich is show n by test in strum ent to be free of flam mab le o rtoxic gas is stated to be gas-free.

"I

Safe for entry:

A space m ay be certified gas-free and be -It safe for m en and cold worke safe fo r hot workCold work includes jobs which can c au se s pa rk s or enough heat toignite an y nearby vapour - e .q, hammering.

Hot work is so hot that it can ac tua lly cause dirty parts of a tank togive off vapour -- e.q, weld ing . This vapour can of course be ignitedby the work.Tests will be carried out by the responsible officer.H e w ill have an instrum en t which can m easure the p ropo rtion offlam mable gas in the atmosphere. It can ind icate the presence o f to xicgas. He w ill u se a special m eter to test a tm osp heres likely to containgases which are very toxic in sm a ll q u an ti ti es .

Remember that the space may not remain gas-free.

page seventeen


20/27

Eddies.

page eighteen

----..

Dispersion M ost petroleum vapours are heavier than air. A fter they escape fromtank open ings and vents du ring load ing they will tend to lie around th edecks. F rom there they can enter doors and open ings facing th e cargodeck . T hey m ay be draw n in to m ach inery spaces and air conditioning

\ ~in takes. Winds m oving at about 5 m .p .h . or less, cause little a ir m o ve m en t.Little air m ovem ent m eans greater danger. F lamm able or tox ic m ix turesm ay not disperse. T hey m ay accum ulate in h e av y c on c en tr at io n s aboutdecks. T hey m ay persist a t som e d istance from where they arise.Q uite rich concentrations can, however, b e d is pe rs ed by qu ite g en tlebreezes. Com plete and rapid dispersion requires a clear path for th e air.

Edd ies If you watch a river flowing past a support of a bridge you will see, onth e downstream side , curren ts sw irling in behind the support, Movingair behaves in a sim ilar way .Air flowing swiftly past sup erstru cture sw irls in around it.This happensespecially on the lee-side. T he passing air causes a sligh t drop inpressure. Some of th e moving air is drawn in , in swirling currents,T hese curren ts are know n as eddies.During cargo operations a wind blowing may -tit contain petroleum vapoure form eddies conta ining petroleum vapour_ deposit dangerous gas near superstructure,


21/27

Vapour must be excluded from qallevs, If this is not possible, electricga l J ey equ ip rnen t m ust no t be used .Vapour must b e e xc lu de d from machinery spaces. F lam m able m ixturesm ust be kep t from the elec trical equ ipm ent in m ach ine ry spaces.Generally dur ing cargo operations the m ain and auxiliary machinery hasto be ready fo r im med iate use. It may not be p ossib le , in c erta inw eather cond itions, to gua ran tee that vapour w ill no t en ter m ach ineryspaces. In these circumstances cargo work will be stopped untilconditions chanqe

. *'.-r-o--- . _ _r K[EP CLus[[)l r! OURtNC ;I CAHGe :l OPERA~}~~~

- - Is" ....\ .._~) ~- !

ee

strictly obey orders regarding closing doors and portsstrictly carry out instructions regarding ventilation and airconditioning intakesuse doors g iv ing access to a cc omm o d atio n from the side ratherthan from the cargo tank area.keep closed all ports and w indow s facing the ca rgo tank area

J,. I,/ \

Ii/

Whenever large am ounts of petroleum vapour accumulate about th e.~decks cargo operations wi II be suspended.During cargo operations or whenever dangerous vapour may be presentabout the deck -

../- " .. . If ' ., . .. .. . ,. . .. _ .. . .. . -~ . .. .-r:--...................-............--~

Do remember eddies.Where they form depends upon wind force and direction.A wind blowing from forward to aft may help gas to accumulate a ft ofan y superstruc ture in its pa th ,A wind blowing across the ship will tend to deposit gas on the lee side. Keep shut!


22/27

Spillage Petroleum s pille d is d an ge ro us petroleum.It can evaporate quickly. Toxic vapours may be released in largeq ua ntitie s. F la m ma ble mixtures may form rapidly. T he sea may becomepolluted.

Hoses andconnections

Defective hoses can m ean spillage.D efective o r badly made connections a re d a ng e ro u s.Sudden s tra in on hoses can cause _ "e defective hoses

. ) ~---- . .~ ...defective connections

.- f, .Il.

.-~f'-- --- Carelessly stowed gear is potentially defective gear.IJi

Pollution O f course, pollution is not a personal hazard or a source of risk to thesh ip. A t leas t w e m igh t no t th ink so at first sigh t.In fact it is a very real threat to the lives and livelihoods of all of us.Even relatively small amounts of petroleum discharged into the sea-particularly in coastal waters-can have a terrible effect on sea rife in '.the area, Its effects on the shorel ine are only too well known.Life may havestarted in the ocean; do not let it come to an end there..At the rates at which tankers load and discharge today, a severe leakageof petroleum is capable of depositing tons of pollutant overboard inseconds,

Petroleum spilled is dangerous petroleum.

page twenty


23/27

Do not use hoses w hich appear defective .Avoid bending flex ib le hoses excessivelv.Hoses should be suspended from suitable equipm ent.M eta! flow boom s should be regularty inspected for tightness ofconnections and absence of str a in on hinged joints.Sometimes an extension is fitted to a manifold connection.Care m ust be taken to avoid excessive stra in to the m anifo ld .W hen a tanker is ber thed alongside, the m oorings m ust be tended .T h is is to check m ovem en t of the vessel an d prevent strain on cargoconnections,

During loading and discharging -e all scuppers m ust be pluggede regularly check overboard to ensure that no petroleum is escapinge sea va Ives an d d ischarges o ver bo a rd w h ich ar e no t be in 9 used

should be shut and lashed

Should a cargo connection leak -e report it to a responsible o ffic er i mm e dia te lyAvoid spi llage at manifolds-It if no perm anent fitting is provided use a portab le drip tray

Use a portable drip trev,

page twenty-one


24/27

There is much more detailed information about safe operationsa vaila ble in your ship, Ask the Chief O fficer. He can help you withinform ation and advice, He w ill make them freely availab le . He w illanswer any of your questions. If you want to read more for yourselfh e ca n r ecomm en d books,

a e twentv -tWQ ...... .....

OTHER CARGOES


25/27

T he m ajo rity of tankers in se rv ice carry petro leum . It is fo r this reason that this b oo kle t h as c on ce ntra te don these carqoes, But you will know that there are other commodities carried in tankers. We thought it mightbe of interest to you if we mention one or two points about some of them.

Books and o ther pub l ications w ill be m ade available deal ing with the carriage o f such cargoes as vegetableoils, chemicals , and fiquified petroleum gas. T h e I nt er na ti on al Chambe r of Shipping , and, o f c ou rs e, individualowner s wil l give full details o f the risks an d p re ca utio ns a ss oc ia te d w ith th es e c omm o ditie s.

..

Vegetable and animal oils and fatsVegetable and anim al o ils and fats ab sorb oxygen from

the air and they ca n cause a deficiency of oxygen in a tank .T his is m ost likely to happen when a tank has been c losed fora long tim e after the oils and fats have been discharged . T heresidual oil or fat on the structures in the tank starts todecompose (rot). When itdoes this, it not only absorbsoxygen , but also p roduces various toxic and asphyx iating gasessuch as m ethane , carbon dioxide and hydrogen sulphide.T hese ga ses m ay also be present in pump rooms or pum p roomdra in tanks, where o ils and fats of this nature rem ain. It istherefo re dangerous to en ter a tank which has been used fo rvegetable or anim al oils or fa t u nles s it is beinqcontinuouslvven tila te d w ith sp ecial atten tion being given to the l owerreaches.

S om e ch em ica ls contain enough oxygen to enable th emto burn without additional supplies from the air.Some chem icals are very dangerously to xic. Some mus t

never be inhaled even in the sm allest quantities. O thers can bea bs orb ed th ro ug h your sk in in to your b loodstream , and soreach vita l o rgans. T hese m ust obv iously never be allow ed totouch your skin.

Special protective clothing will be m ade available to vou .Finally , som e chem icals are extrem ely corrosive.

Sulphuric acid is an obv ious exam ple, bu t there are others.Corrosive chemicals can burn you severely if they to uc h yourskin. They may blind you if they enter your eyes .

Protective clothing is e sse ntia l w ith corrosive chemicals.G oggles w ill be necessary . A complete su it w ith he lme t mayb e re qu ir ed .

Chemica l sT he simple word c hem icals co ve rs a vast an d complexrange of commodities. T here are already well o ve r th re e

hundred which can be ca rried a t sea in liqu id form. Many ofthese are entirely harmless; o thers can be ex trem ely dangerousif mishandled. T he risks and precautions are basically similarto those fo r petroleum . T here are , how ever, further problems.

All chemicals have hazard warnings which descr ibeh ow d an ge ro us they are in a num ber of respects. By propera tten tion to these warnings your o ffic ers c an " tell exactlywhat precau tions are necessary.

page twenty-three


26/27

Liquefied gasE lsew here in th is book we have m en tioned liqu id

fo rm in g v ap ou r by evaporation . T o do th is a liqu id m ust useheat. T his may seem strange when we th ink of very volatileliquids with flash points below OC (like gasoline for instance).Y et even they are using heat as they evaporate . T o changefrom liquid to pure gas t he liquid actually has to boil.

very rapidly indeed. It therefore needs a great deal of heat in ahurrv , It can only obtain this from its su rroundings. Metal, air,any th ing in the v icinity o f the leak has to give up heat to theevaporating liquid. They become very cold.

If you approach the leak or touch its immediatesurroundings without adequate protection you can be qu iteseverely injured. The injury is like a burn. In fact it is calleda frost burn .

Never approach a I iquefied gas leak w ithout adequateprotection. Do not touch bare metal surrounding such a le ak .--- Add itiona I tip

Incidentally, th is refr igeration effect is the reasonwhy, when you are using a portab le carbon dioxide firee xtin gu is he r, yOU shou Id never hold the m etal can ister.T he rapidly expanding CO 2 g as is taking heat from itssurround ings so rapidly that the container becomesdangerously cold. Hold the sh ie ld a ro un d the nozzle - itis m ade of an insulating materia l .

Do you know how most domestic refrigerators work?A gas is compressed. Under pressure now it is cooled and turnsto liquid. If this liquid is then allowed to expand it evaporates,boils and turns to gas once eqein. The expansion is made totake place in pipes inside the cabinet of the refrigerator. Theonly place from which the evaporating liquid can steal itsrequired heat is from the contents of the refrigerator. Theycool down as they give up this heat. The expanded gas goesback to the compressor to start its journey allover again.

W hen a I iquef ie d g as escapes it evaporates (and boils)

oaae twentv-fou r


27/27

Emergencyprocedure

It may be necessary for you to enter an atm osphere which is unsafe .(You may have to rescue somebody)Before YOlJ enter a tank a responsible officer will ensure that -e you wear bre athinq apparatus_ you wear a lifelinee the lifeline is or operlv tendedtit a watch is k ep t on youe a means of communication existse a system of signals is agreede you an d everybody else involved understands the siqnalsHe will also rnake sure that-e a back-up or rescue squad is equipped to ren de r assistan cee resuscitation equipm ent is on handIf you have to keep watch or tend a lifeline ----e keep a careful watch on your mates belowIf you cannot se e thern -e callout to them frorn time to time_ rna ke su r e they a r l swer .If they do no t answer repeated calls: or rf they show signs of drunkennesso r u nusu al behaviour -__ RAISE THE ALARM IMMEDIATELY- DO NOT ATTEMPT TO RESCUE THE VICTIM BY YOURSELFe DO NOT BECOME A VICTIMa

safety in oil tankers

Documents