Document QgvEZ4pb5yRB7GbayV57e7zE4

NI9515 K f 0019590 (a) Object Th is booklet has been prepared with the object o f creatin g a better un derstan din g o f th e: lead h azard s, as d istin ct fr om oth er h azard s, encoun tered in th e cleaning o f storage tanks wh ich have con tain ed leaded gasoline. Regulation s govern in g th e clean in g, scalin g and repairing o f tan ks wh ich h ave con tain ed lead ed gasolin e h ave been issued b y Th e Associated Eth yl Co. Lt d , an d th ese regu lation s m ust be read in conjunction with the subject m atter o f this booklet. com pounds and thus m ake dangerous to breathe. Slud rem oved from a tan k is han dle, even wh en wet, and be taken to avoid exposure in g from it. (ii) Ru st scale on th e in sid contain s traces o f lead, and from this scale m u st be avoi (iii) T h e residual vapour both asphyxiatin g and pois n ot be breathed in an y circu (b) Nature and Source of Hazard Organ ic com poun ds o f lead, wheth er in liq u id , solid or vapou r form are h igh ly poison ous. Tetr aeth yl lead is an im portan t exam p le o f this typ e o f com poun d. I t can be absorbed into th e h u m an system either b y th e in halation o f its vapour, by skin contact, or through the m ou th , with serious or even fatal results. It sh ould be realized th at th e n ature and sym ptom s o f organic lead poison in g are quite differen t fr om in organ ic lead poison in g or plum bism . As an exam ple, a tum blerfu l o f tetraeth yl lead com p letely evapprated in a 4,000 ton storage tan k will produce an atm osphere which, m ay be fa tal a fter an h ou r 's exp osu r e. An y tan k which has at a leaded gasoline, and has no cleaned th ereafter, m ay pres o f lead exposure, irrespectiv o f tan k3 fr equ en cy o f clean location, len gth o f service, e n ot th orough ly clean ed this even i f a differen t prod u ct, s subsequen tly stored. Even wh en all slu d ge and been rem oved, and the tan k ha ven tilated a n d gas-freed , ai h a nam ely that repair work, in vo tion o f heat, m ay result in th lead com poun ds still present the m etal and particularly in h After rem oval o f the gasoline fr om a tan k wh ich is to be cleaned, the m ain dan gers to person s en terin g th e ta n k arise from : (i) Slu dge on th e tan k bottom ; (ii) Ru st scale on the in side su rfaces; and (in) Residu al gasolin e vapours. 2. RESPONSIBI It is recom m en ded th at th be responsible for th e who operation, and n o work shou without his written authority (i) D u r in g storage o f lead -tr eated gasolin e, sm all quantities o f organic lead are deposited on the bottom o f the tan k an d rem ain in suspen sion in the sludge on th e tan k bottom . Th is sludge will vary in d epth according to th e am ount o f water presen t an d the degree o f irregularity o f th e tan k bottom , an d will consist gen erally o f water, rust an d scale, tetraeth yl lead an d its 3- PLANNINGTHE Th e whole operation shou the Ch ief En gineer who shou on the followin g points: (a) Method of Cleaning Certain alternative m ethods o f sludge will b e described later 1 K- 0019591 in volved , sh ould first b e ch osen . H e m u st th en satisfy h im self th at each m an in th e tan k clean in' Pg c'r e1w 1has r.e':i.a 'd a.n d' u"]n d er stood th e r cOgu la- t ion s. (c) M e d ica l E xa m in a t io n Exp erien ce has shown th at certain diseases and disabilities can m ake th e wear in g o f p r o tective equ ipm en t u n d u ly onerous. It is r ecom m en ded, th erefore, th at befor e bein g selected for tan k clean in g, workm en b e m ed i cally exam ined to ensure that they are in good h ealth an d n ot sufferin g fr om an y d isability wh ich m igh t seriou sly in terfere with th eir work. I f this be done, an d th e prop er precautions obser ved , th ere will be n o in ju r y to h ealth from th e lead hazard durin g tan k cleaning. As a gen eral p r ecau tion , n o m an wh o has a perforated ear-drum should be em ployed in a tan k wh ich has n ot been com pletely gas-freed, as it is possible for a p er son so afflicted to breath e gasolin e vapours th rou gh the ears. (d) Cloth in g an d P ro tective E q u ip m en t All protective cloth in g an d safety equipm en t m u st b e car efu lly in spected b y th e forem an , wh o m ust satisfy h im self th at it is in first-class con dition before wor k com m ences. Th e tan k sh ould n ot b e en tered (even for a short period) until it has been thoroughly ven tilated an d all residual vapours an d sludge rem oved, unless th e person con cern ed is adequately protected against skin con tact with th e sludge, an d has an air su p p ly wh ich is com pletely in depen den t o f th e air in the tan k. Th is can on ly h e assured b y: (i) Wearin g protective cloth in g as set out in Section I .A. o f th e. Associated E t h yl Com p an y5^ T a n k Clea n in g Regu lation s; and (ii) U sin g a p ositive-p ressu r e fu ll fa ce-p iece air -lin e m ask with hoselines an d blower. M en so equ ipped sh ould see th at th ey h ave a d e a r p ath erf-escape in th e even t o f an accid en t p u t on clean clothes. H oses for air m asks sh ould always be test testin g, or later wh en in tive odour, such as g user sh ould leave the t cause and rem edy it, H ose con n ection s sh ou fittin gs sh ou ld be teste dam age or leakin g, a strain s wh ich can be hoses inside a tank. T h e in take o f the air to win dward o f the ta fresh uncon tam in ated the m en inside the tan .(e) M e c h a n ic a l E q All equipm ent wh ich wor k, su ch as fire ho pum ps; ejectors and exam in ed b y th e fore h im self th at all m ech good ru n n in g ord er b (f) Provisionof Sl Th e forem an sh ou l for the burial o f slu provided. Th ey should to take all th e m ateria an d should h e located to be disturbed at a lat Au th or ity to com m e sh ould n ot bei given u n til all th e above co sa t isfie d . 4. M AN H O Th e job o f rem ovi fr om a tan k wh ich is presen t a sign ifican t h o f lead an d gasoline open in gs. It is im por m en u n d ertakin g this w 2 K 0018592  .-- here m ethods o f ven tilation are d escribed . 5. R E M O VAL O F S L U D G E Th er e are several ways o f r em ovin g slu d ge from a tan k, an d th e forem an sh ou ld b e fu lly in structed in th e m ethod to be em ployed. (a) Facilities at Tank Th e experien ce o f som e com pan ies is th at substantial savin g ip tim e an d m u ch greater con ven ien ce in clean in g tan ks can be effected b y rem ovin g on e com plete p late from the bottom strake o f the; tan k, thus leavin g a large open in g th rou gh wh ich slu d ge can b e flu sh ed by means o f high-pressure water hoses. Th is m ethod has the advan tage o f easy en try and exit, b etter ligh t an d ven tilation , an d alm ost elim inates the n eed to h an dle th e sludge. H owever, before adoptin g this m ethod, the tank design should be investigated to see that th e structure is n ot weaken ed !by t h e rem oval o f a plate. F ig. 1 shows th e open in g provided when a plate has been rem oved in this way. Figs 2 and 3 illustrate the added con ven ien ce an d im proved illum in ation . T h e ideal type o f tan k fr om th e clean in g poin t o f view is on e with an ojpening or drain at the lowest poin t in the tan k bottom , but even in th e case o f tan ks to wh ich su ch outlets h ave been fitted, the advan tages to be gain ed b y rem ovin g one or m ore o f the plates fr om the bottom strake wou ld fu lly justify this procedure. Obviou sly, th e best tim e to fit a d rain age out let is durin g the con struction Ofthe tan k, b u t it is possible to in stall a sim ilar d rain as a field m odification t o an existin g tan k, as sh own in Fig. 4. On ce such a d rain has been fitted, th e greater part o f the sludge and loose scale can be rem oved before en terin g, th us greatly reducin g the lead h azard . W h er e th ere is n o suitable drain age outlet from the tan k, the use o f a p ort able pum p or an ejector is desirable for rem ovin g the bu lk o f the sludge, in order to reduce the len gth o f tim e th at the m en ivould h ave to (b) Water Flushing Met T h e safest wa y to r em ove is to do th e wor k en tirely fro person actually entering the ta and loose scale h ave been r cases this can b e don e an d, effectively, it has th e advan ta large exten t the risk o f expos m en concerned. Th e water necessitates the u se o f h igh pr 100 p.s.i.j), fire h oses, and a ejector for rem ovin g the slud th e tank. (Wh ere there is a bottom drain in the: tan k no 5required). A suitable ejecto F ig- Th e water is directed throu flu sh th e r iggin g, walls, an d tim e, th e p u m p or ejector is op the water-sludge m ixture. Th in g and ejectin g is continued loose m aterial has been rem o Usu ally this takes from o depending upon the size o f am ount and nature o f the slud th e flu sh in g is con tin u ed u n ti the tan k is as clean as the in -go I f the m en operating the h the tan k detect gasoline or o sh ould im m ediately p u t on th W ith large tan ks, it m ay be wearin g air-lin e m asks to en te the hoses so as to rem ove sl areas difficult o f access. In su ferable to rem ove as m u ch sludge an d loose m aterial b y o from th e outside before se com plete th e flush in g opera ben efit o f pr op or tion ately r h a za r d . Th e slu d ge sh ou ld be disch lee d in g to a p r eviou sly prepar capacity to h old all the slu d 3 0018593 Fig. 4. Alternative drainageoutlets 4 -E FOR FLOATING MATTER 3 ^ * +* -* ; * - . m ' i W > . * -wi* i ` i*fF i, J.******1 N * 'V "V"** Fwiga.te7r. Bcornonomectwiointh 5Mv&r W^ W Ad ju s t Aon m a PUMP SUCTION W at er Fig. 5. Water-sludgee 5 o f three feet sh ould be allowed. In certain cases n on -adh eren t lead deposits and sludge th e it m av be possible to flush th e sludge and water sh ou ld be gas-freed before com m en cin g th rough a drain into th e sea, bu t this will depen d repair or pain tin g operation s. If, h owever upon local regulation s regardin g disposal o f tan k has been clean ed m erely for th e purpo effluen ts fr om factories an d plan ts. chan gin g prod u cts, it sh ould n ot be necessa T h e for egoin g is a gen eral procedu re for tan k proceed fu r th er th an th e elim in ation o f cleaning: wh ich will in volve th e m en in th e slu d ge an d n on -ad h eren t m aterial on th e absolute m in im um o f exposu re to toxic vapours, bottom . bu t necessitates th e u se o f a large qu an tity o f water to flu sh ou t the sludge. In certain cases it is n ot practical to have a large volum e o f water run n in g to waste, because either there is in su f ficien t water available, or th e tan k bottom s are so close to the natural groun d water-level that there is in adequate drain age. In such cases it is still possible to u se th e flu sh in g m eth od b y con structin g a double in terceptor p it consistin g o f two pits or holes con n ected b y a tren ch as shown in Fig. 6. A baffle sh ou ld be so placed th at any gasolin e or oily susbtan ces floatin g on th e su rface o f the water will be preven ted from passing between the two pits wh ile still perm ittin g the flow o f water from on e p it to th e oth er. An oth er baffle to p r even t solid m ater ials passin g between the pits will also be required. T h e first p it is u sed as th e d epositor y for th e effluen t fr om th e tan k, an d th e secon d as a water (d) Supervision Th er e is a need for con stan t supervision b forem an o f all clean in g operation s to en sure m en do n ot rem ove th eir air-lin e m asks w inside the tan k. Th ese m asks can un doubt becom e m ost un com fortable, esp ecially at tem peratures. Each face-p iece sh ou ld thoroughly tested to m ake certain that on ly air from th e blower can be breathed. D u e to possibility o f the presen ce o f gasolin e fu m es air deficien t in oxygen , can ister m asks m never be used in a storage tan k wh ich has been th or ou gh ly clean ed an d ven tilated. Su pervision is also necessary to en sure th a m en en gaged on work in leaded gasolin e t ch ange th eir clothes an d wash before takin g m eals, as laid d own in Section i a o f th e R lat ion s. reservoir. A portable h igh -pressu re pum pin g u n it (such as a fire pu m p) is requ ired , takin g its 6. DISPOSAL OF SLUDGE suction from th e r eservoir p it, an d deliverin g water to th e fire hoses u sed for flu sh in g th e tan k in terior. It is d esirable for the water in the reservoir p it to be as fr ee as possible o f suspen ded m atter. Th e size and typ e o f con struction o f the pits are govern ed by the capacity o f the tan k and the con dition s at th e site. I f the tan k is clean ed b y th e water flus m ethod th e sludge will be discharged direct a p it as already described. Wh ere th ere i water available for th is m eth od , th e sludge m be rem oved in bu ckets, or, i f a plate has b rem oved, wheelbarrows m ay be used for purppse. All m en h an dlin g slu d ge in this m an (c) Cleaning Without the Use of Water outside thq tan k sh ould be equipped can ister typ e gas-m asks u n til su ch tim e as W h er e there is n o water available for flushin g slu d ge p it has been back-filled . the tan k in terior it is desirable to p u m p out as mudh slu d ge as possible before m en en ter th e Th e p it sh ould th en be m arked with a n o warn in g that lead sludge has been buried tan k to rem ove th e rem ain d er. Broom s, bu ckets, sh ou ld n ot b e d istu rbed . T h e n otice sh ould and possibly a rubber squeegee should then be used to d ry u p an y sludge rem aining, in pools num bered and dated to correspond with poin t record ed on a m ap o f th e installation . 6 that it has been p r op erly back-filled , and th at th e lead hazard has been com pletely elim in ated. T h e warn in g n otices sh ould be in place an d a record m ade o f the location o f the pits. An y area around the tan k wh ich has been contam inated sh ou ld be d u g over an d th e con tam in ated earth b u r ie d . (b) Mechanical Equipment and Tools Care sh ould be taken to see th at all tools are rem oved fr om th e tan k. Th ese, an d an y m echanical equipm en t used, should be th orough ly clean ed before bein g stored. (c) ClothingandProtectiveEquipment All clothing should be collected and washed at th e en d o f each d ay's wor k an d a t t h e com p le tion, o f th e job. All ru b ber equ ipm en t, air-lin e h oses, fa ce-p ieces, boots an d gloves sh ou ld be washed and dried im m ediately after use. (d) Bathing AH m en sh ou ld ch an ge th eir cloth es an d bath e at th e en d o f each d ay's wor k an d wh en ,,the job is fin ished . (a) Cold repair work i dust, an d for this reaso out under Paragraph VI I scale" are applicable. (b) F or repairs in vo im portant th at the parts as the areas around thos heated, be clean ed d ow reason for this is th at weld m ay volatilize solid lead th e surface o f th e m etal, h azard . Ta n ks wh ich h ave lea be treated with special gasoline wh ich has seeped the groun d beneath, can danger. It is im possible t elim inate the lead hazar cases an d, th erefore, it for th e m en carryin g out fu lly equipped with prote lin e m asks. U n t il th e .fl it will not b e safe fo r m without wearing protect P R I N TE D AT TH E BR O AD W ATE R P R E SS, W E L W YN GAR DE N C 0018597