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prool' (.such as air= driven) dot one corner of the sectio.
<br />After' the hole is. drilled, the tank _vapo(s must .again he
<br />lcstcd by inserting the meter probe into clic hole to vcril•Y
<br />that the vapor concentration dos nut exceed 10 percent
<br />LI -L.
<br />Nutc: It is important that the purg,rg..air ventilatio,i arnd
<br />testing continue throughout the entire iinino op
<br />cration. During the tank cutting operatian n,irimal
<br />air pressure should be maintaii,ed to prcvcnt a blow
<br />oul.
<br />'File tank should be cut using an explosion,prool (such
<br />.as air -driven) saber saw or s.nipper using lubricating oil to
<br />reduce friction, heat and possible sparks. Prior to the fir,aj
<br />cut, the plate should be supported to prcvcnt its falling into
<br />the tank.
<br />6.0 Tank Entry
<br />13clore entering tanks, the procedures -described in API
<br />Publication 2015 "Cleaning Petroleum Storuge Tusks
<br />and 2015A, "A Guide for Con irolliiig the Lead lla and
<br />ilasoc•iutc•cl with Tank Entry and Cleaning", should be fol- .
<br />lowed. This includes checking the oxygen content inside
<br />tine iarik will, a properly calibrated oxygen n.onitor.
<br />At all tines, personnel e;ut cd
<br />with positive pressure air supprMt-eOuipn,ent tvith fd face
<br />encio urc and safety harness connccted*to a safety line held
<br />by an attendant outside the tank:. Oii and water resistarn;
<br />rubber or neoprene boots and gloves shall be worn. Clotho,"
<br />shall cover the arms, legs, torso and head of tank entry
<br />personnel. Disposable clothing, impervious to product,.
<br />is
<br />preferred. Clothing saturated with product small be removed
<br />irnn,cdiately. All .personnel working; inside the tank should
<br />be familiar with ANSI LI 17. 1 ".Co,fine,cl Spaces Safety
<br />Tcsts with the combustible gas indicator and oxygen mon-
<br />itor should.be performed periodically in tlnc tank to ascertain
<br />that the tank vapors and oxygen content are in tlnc safe range.
<br />It should be recognized that if'the tank is perforated, product
<br />ur vapors which have leaked into the soil- may re-enter the
<br />tank through a perforation. The vent line shall remain clear
<br />arid unobstructed to allow continuous ve,itilation. All other
<br />lines and openings shall be plugged or capped off to insure
<br />Ilei liquids or vapors may enter the tank during the lining
<br />oper,tMil.
<br />7.0 Preparation of Tank Interior
<br />7.1 Sludge Removal
<br />' Slud}te accumulation on the button, of the tank must I)e
<br />rcnit)ved and placed in tightly scaled containers. It nn.ust be
<br />disposed of in accordance with local, state and federal reg-
<br />ul'ations, which may require nnaridatory docunnentation as
<br />well as sale disposal.
<br />Note
<br />1 ar,k slud,e ;u;d scale are potentially hazardous as
<br />they ,n;ty contain te;rac;hyl lead vapors which can,
<br />be inha!ed, or toxic liquid tetraethyl lead which
<br />nnay be abs -ori c l through the skin..lf the dry in-
<br />ternal surface .ol' the tt:nk, is scraped, the resulting
<br />atr;,usi)hcrc maty contain dangerous quantities of
<br />lead. The quantity of lead in clic tank atmosphere
<br />should be checked using a lead in air analyzer. .
<br />7.2 Tank Inspection
<br />During inspcctiun, (lie entire interior surface of the tank.
<br />shall be inspected using a light fixture approved for Class
<br />I, Division 1, Group D - Hazardous Locations. The struc-
<br />tural integrity of tf;c steel shell around perforations (holes)
<br />Of areas of severe corrosion should be deternnitied by tapping
<br />with a brass ballpccn hammer. Sufficient steel shell must
<br />renrai,r intact (af(er abrasive blastin) to provide structural
<br />support for the inter for lining. Thefollowing guidelines may
<br />be utilized to identity a tank that n,ay be repaired.
<br />l . A -tank havinc an open scam or split no longer than
<br />three (3) inches; or
<br />2. A tail: hwin1 a perforatiun no larger than one and
<br />one-half 0 '/) inches it, diannetcr except under the
<br />gauging opcni,;_ where the perforation may be no
<br />larger than two and._ane halt: (2''/z) inches in diameter;
<br />or.
<br />3. A tank with less than five (5) perforations (none.larger
<br />than one half incl; in diameter) in any one square foot
<br />arca.
<br />a. A 'tank with less than twenty (20) perfdrations (none
<br />larger than one hall, inch in diamctcr) in a five hundred
<br />(500) square fool arca.
<br />"ranks that exceed any ol' the above should not be interior
<br />lined unless approved by the aud.ority having jurisdiction.
<br />To determine adherence to these guidelines, perforations
<br />'
<br />and scares shall be brass bailpccn hammered (before and
<br />after abrasive blastin,). to remove thin metal and obtain
<br />structurally sound cd,cs. Perforations and scam splits shall
<br />be reamed until the edges of tl,,c hole or split are a minimum
<br />of ''/x" thick.
<br />N'
<br />7.3 Surface Preparation
<br />All blasting per. c( inncl should b,: familiar with the hazards
<br />described In Ai'1 Publication 2027, "/gn,iriun tlu:ards lir•
<br />'
<br />vulve,d In i1Gru.,ive /llcr.uiitg of Tan,n.r int Service". All per-
<br />fura;ic ns shall be plu,ccd -lih boiler plugs or hydraulic
<br />cenncnt prior to ,braslvQ blasting; scams rimy be plugged
<br />hydraulic•ccntcnt.
<br />with '
<br />CAUTION: BLI=O!�i-: ABRASIVE BLASTING, THE
<br />T111INK SHOULD 81: CHECKED 'AGAIN
<br />THL: CONIBUSTIBLE GAS 1ND1-
<br />
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