NTSB Safety Recommendation Letter P-76-020 through P-76-021

Page 1Official PDFWASHINGTON, D.C. Hon. W i l l i a m T. Coleman, Jr. Secretary DeDartment of TransDortation Washington, D. C. 20590 1 SAFETY RECOMMENDAT ION (SI P-76-20 and 21 i A t 8:30 p.m. on February 25, 1976, a Mid-America P i p e Line System (MAPCO) 8-inch l i q u e f i e d petroleum gas (LPG) p i p e l i n e ruptured near Whitharral, Texas. The escaping LPG vaporized, formed a low-lying cloud, and i g n i t e d . Flames roared skyward i n excess of 200 f e e t and engulfed a 3/4-mile-long by 1/4-mile- wide area. The f o r c e of t h e rupture created a c r a t e r 20 f e e t long, 1 2 f e e t wide, and 5 f e e t deep. There were 5,415 b a r r e l s of LPG (227,430 gallons) released and burned. The occupants of two dwellings i n t h e area were burned severely, and f i v e were k i l l e d . The flames receded toward t h e ruptured pipe- l i n e where they were extinguished a t 5:OO a.m. Investigation showed t h a t t h e longitudinal seam of t h e 8-inch pipe had s p l i t . The 8 l/Z-foot-long s p l i t w a s located on t h e s i d e of t h e pipe a t t h e 9-o'clock position. The pipe was manufactured by the Jones and Laughlin S t e e l Corporation i n 1960 and had the following s p e c i f i c a t i o n s : 8 5/8-inch o u t s i d e diameter API 5LX-52 e l e c t r i c r e s i s t a n c e weld (ERW) .219-inch w a l l thickness 2,650-psig i n t e r n a l pressure a t specified minimum y i e l d s t r e n g t h ( S M Y S ) 3,350-psig ultimate b u r s t i n g s t r e n g t h When t h e pipe f a i l e d , t h e pump s t a t i o n was operating a t 1,570 psig (about 59 percent of S M Y S ) -- well below t h e 72 percent of SMYS specified by Federal regulations. When t h e l i n e was constructed, t h i s s e c t i o n had been t e s t e d h y d r o s t a t i c a l l y t o 1,660 p s i g f o r 8 hours. The MAPCO LPG system has sustained a series of l o n g i t u d i n a l pipe s e a m f a i l u r e s . From January 1968 t o t h e d a t e of t h e Whitharral accident, 14 longi- tudinal pipe seam f a i l u r e s occurred which r e s u l t e d i n 6 f a t a l i t i e s and t h e l o s s of over 60,000 b a r r e l s (2,520,000 gallons) of LPG. Of these 1 4 seam f a i l u r e s , 10 occurred i n 8-inch pipe and a t pressures ranging from 1,265 p s i g t o 1,570 psig; t h e average pressure w a s 1,445 psig. 1825#

Page 2- 2 - A s a result of an accident 1968, the Nebraska State Fire Marsh pressure and to hydrostatically ret tests, 195 longitudinal seams failed. The average pressure at which the failed was 2,235 psig. This pipe also was manufactured by the Jones and Laughlin Steel Corporation. Metallurgical analysis revealed that most the accidents were caused when the electric resistance weld (ERW) in th longitudinal pipe seam failed. Therefore, the National Transp the Department of Transportation: Review all pertinent dat submitted by liquid pipeline carriers to determine if longitudinal weld failures constitute a recurrent safety problem, and take appropriate regulatory action if they (P-76-20) (Class 11, Priority Followup) Request all pipeline companies which have installed ERW pipe manufactured by the Jones and Laughlin Steel Corpo- ration to review their records on longitudinal seam failures and determine if the number of such failures is abnormally high. After DOT reviews these data, it should take necessary corrective action. (P-76-21) (Class I, Urgent Followup) TODD, Chairman, McADAMS, HOG in the above recommendations. NAIlONAL IRANSPORIATION SArCIY BOARD TVASHINCTON DC 20191 OFrIrlAL nUS1NEsS PRIORITY MAIL PENALTY FOR PRIVAIE USE $300#