Document NERQn98YL0yyXkB1OG4M7VRap

UNUSUAL INCIDENT 2*4 S3 UI .0 tit cz jjw-'s s; -e 'ti -? ( w, .'i -- o 1i`> n. . . JSR - .-Kv '.i'-'ls- ", t _ "iv*.1- *< / .V * -Vj / ; Date: February 18, 1976 Area: "Ponsol" Spray Dryer #2 -- 743 Bldg. Mature of Incident: Leak of propane to atmosphere. DESCRIPTION At approximately 9:30 p.m. , the operator was starting the dryer to dry Charge 184 of "Latyl" Yellow 3G Disp. Cr. He opened the automatic valve in the propane line by pushing the panel board switch. The propane is stored in six propane storage tanks across the street and southeast of 743 Building; the automatic valve is at this location. The pilot light lit without incident, but the main burner would not light because of low gas pressure {as indicated by panel board lights). The operator noted a strong smell of gas when he checked the burner on the fourth floor outside platform. He also noted that a relief valve was missing from the system. He called his co-worker on the intercom and the automatic valve was shut off immediately. He then went across the street to the propane storage tank where he again noted a strong smell of propane and also noted that two relief valves were missing at this location. The operator called the night office and his super vision at this point. An investigation immediately following the incident revealed that the three relief valves had been removed on the day shift for routine inspection and that the 3-way valve beneath each relief valve had been set wrong (see attached sketch). The 3-way valves were reset properly and the unit was started up without incident. The inspected relief valves were installed the next day. The investigation also revealed that approximately 500 gallons of liquid propane was discharged to the atmosphere over a 15-20 minute period. INVESTIGATION 1. The mechanical foreman lined up his mechanic on the 8x4 shift to remove the three relief valves and take them to PVI for inspection. The foreman reviewed the job directly with the mechanic, and the mechanic assured him that he knew how to do the job. He had done this same jot six months previously and had sketched the 3-way valve in his notebook,. However, for some unknown reason, he made a mistake in his sketch, and instead of closing the valve, he opened it. The spray dryer was shut down for clean-up when the valves were removed, so the automatic gas valve was closed and there was no pressure in iihe gas line. Therefore, the mechanic did not realize he had set the valve wrong.. 2. The regular operator, a Leader C/P who is in charge of running the spray dryer, was off this particular day and only his helper, an Operator 2/C, was present when the valves were being removed. The helper had no knowledge of the workings of the propane system, tut tagged out the 3-way valves with the mechanic. No other member of operating super vision knew the jot was being done. 3. Normal shift turnover is a written report in the shift log and conversations between the incoming and outgoing shift leaders. In the absence of the 8x4 shift leader, the operator ?,'C did not write down or tell the incoming shift leader that, the relief valves had been removed, since he believed the 3-way valves were properly set and the system war. safe. (Over] Kr.v K r. t' i. t :#1 i * e t' ' '.4 F; . &?4? MU-2406 DU PONT CHAMBERS WORKS V.3 N32962 DU P050467607 INVESTIGATION (Cont'd.) 4. The maintenance foreman was unable to contact the Spray Dryer supervisor. His attempts to contact higher supervision Were unsuccessful because he was unaware of the complete structure of the spray dryer organization; Engineering Area 3B maintains the "Ponsol" Spray Dryer *2, but has no other contacts with the "Ponsol" Area. CONCLUSIONS 1. The basic enusp of the incident was failure to follow established valving and tagging procedures. 2. It 5 s a recognised procedure for the mechanics to operate the 3--way valve since a wrench is required to turn the valve stem. However, the correct position of the valve was not checked by a qualified operator or b3' members of either Engineering or Operating Department supervision. 3. The mechanic did not realize that he was working from a faulty sketch. 4. An Operator 2/C tagged out the valves as a representative of the Operating Department. He was unfamiliar with the system and was not authorized to do any locking or tagging. 5. Because of poor communications, there was incomplete shift turnover ty both the Engineering Department and the Operating Department. RECOMMENDATIONS 1. Relief valves in the propane system are not to be removed until the procedure is re viewed on the spot ty members of the Engineering Department supervision and the Opera ting Department supervision CL. P. Winfield and C. H. Turner). 2. Valving and tagging is to be done only by operating personnel specifically authorized by area management CC. H. Turner). 3. Area supervision will strengthen shift turnover procedures to assure that all informa tion is included and reviewed (H. R. Steinbruck). 4. Tiro--part red tags will be adopted by Operations at "Ponsol" S.D. *2 so that an on-thespot reminder of uncompleted work will he present in the Operating Control Room CC. H. Turner). 5. Consideration will be given to replacing the dual relief valve system with a single relief valve or replacing the present 3-way valve with one of another design CW. J. King and J. J. Pietrantonio). )nvestigated by: M. L. Reinhart H. R. Steinbruck C. H. Turner W. J. King [ Reviewed by: J. J. Meyer L. F. Winfield J. J. Pietrantonio J. E. Olcott L DUP0504676Q8 X.-2 rk 0 leh'f\>u b-c 1` 11 V * l - _______L______________ i_______ T`i!eh c orr^i.r- x./tc*Ys<*fTtr * . . ........... - ^ j-JD3RV' throe-way H u a Ij sh u f-of f valves CJLjOI-r^ ........-..Type 92 Parallel Mounling ( r:?.cro 3Ras s v alLVE -----------------------------' R fM Outlet r=n 0;ci> ^^ tell Outlet Fill C.oseJ ' INLET Recommended lor use with Relief Valve Types 52, 523, 524. c 5t - r=^V >15e302-A r-tcMcl Mounting niLC IRON VALVE r,x XX 2___ i Iff pt~?~l-- K~ Mill INLET Type 8023 ParcIteJ Mounting SEMI.SirrL VALVE lc!i Outlet Toft Open Owiitt rail For Duo! Relief Votves and Drier By-Pcss Inslollolions or Applicoti:.-.s requiring simuiloncous opening of one line and closing of another. Three-Way Dual Shut-off Valve Inlets are shown at the bottom of the illustra tions. Tight shut-oli can be obtained at - either extreme of stem position, dosing ,, oil either* the left or fight outlet port. When the valve stem is in an interims 'Plate position, the how is through both cutlet ports. ** - A dual relief volvc installation consists of one three-way shut-off valve and two -relief valves so arranged that both relief valves cannot be shut olf from the pro tected pressure vessel at the same time. This permits safe removal of either relief :- valve for repair or replacement, while the vessel is protected and under pres sure. EACH relief valve must have suffi cient capacity to provide the necessary - discharge flow when used alone.. . . The desifin of this 7hrce*VVoy V* -.e provides fuir discharge arcA through -e valve regardless of stem posd*cn. in suring minimum protection. fur;r *rmofc, this doSTn prov.des for conven ient parallel mounting ol tne Iwo ft ef valves end iidhlis the rraurmenl iex lotlh in the ASA D9.1 15o4 Coco Sec tion i2.i. y. "No slop valve shall be located ;eIwern any automatic pressure re *1 device or fus'Llc plug and tiie pan or parts ol the systrm proiecled tnerery. except when the parallel relief dev. mentioned m 13.2 af<* so arransec fat oniy one can bu rtmdcre 0 moocfa"vt at * a time for test or repair purposes." Two three-way valves, installed v-tr drier bypass line, permit installation or removal ot service oner witnout air. orb. or moisture entering line. PARALLEL MOUNTING--CAPPED TYPE, BOTTOM INLET 450 P.SJ. Working Pressure. Moximum Temperolure Rcling 300F. CAT At OS SIZE KUKKCSS COM'KEC1J0NS BODY MATERIAL Diy.srfsiofts-iNCHEs tNUT CEKUR 10 IHIET fACt cuurr f l BOAT ] CAP ClKlfcfl ] fD 100UULT PORT I AC15 CLftHRS wncH* fOUMS .? -1021A 02?A fS22A-B 021 </r f .p.t . >/,' F.P.T. >.i' F.P.T. r f .p.t . nr F.r.T. Fe;ed Eras; Ductila Iron DuclTe Iron Ductile Iren Semi-Steel 2 Vi* Hi 2:,t* tv. tv. 311 iV, v /m 6V5 7 V/i tv. 311 355 4/i 21* i 33 3-/, i'A 4M. 6 4Ji is;: 3 1 DU P050467609