NTSB Safety Recommendation Letter P-79-002 through P-79-005

Page 1Official PDFNATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. ISSUED: May 15, 1979 Chairman and Chief Executive Officer Mid-America P i p e l i n e System P-79-2 through -5 Tulsa, Oklahoma 74119 i 1800 South Baltimore Avenue A t 12:OZ a.m., c . d . t . , on August 4 , 1978, propane t h a t had vaporized and spread widely from a ruptured 8-inch l i q u e f i e d petroleum gas (LPG) p i p e l i n e owned by t h e Mid-America P i p e l i n e System (MAPCO) was i g n i t e d by an unknown source i n a r u r a l a r e a near Donnellson, Iowa. The j n t e n s e fire k i l l e d two persons and c r i t i c a l l y burned t h r e e others; one of the c r i t i c a l l y burned persons l a t e r died. A farmhouse and s i x outbuildings were destroyed, and two adjacent homes were damaged. &/ The MAPCO p i p e l i n e extends from w e s t Texas t o Conway, Kansas, where it forms two branches. One branch extends t o Minneapolis, Minnesota and t h e o t h e r t o J a n e s v i l l e , Wisconsin. The p i p e l i n e is more than 5,000 miles of m u l t i p l e l i n e s from 4 inches t o 1 2 inches i n diameter. The s e c t i o n of p i p e l i n e involved i n t h i s accident extends from a pump s t a t i o n a t Birmingham Junction, Iowa, t o s t o r a g e tanks f o r t r u c k loading f a c i l i t i e s a t Farmington, I l l i n o i s , a d i s t a n c e of 1 1 7 miles. This s e c t i o n of p i p e l i n e , c a l l e d t h e Farmington l a t e r a l , was engineered and inspected by MAPCO personnel and i n s t a l l e d by an independent contractor i n 1962. A t t h e time of t h e accident, propane was being transported through MAPCO's main p i p e l i n e system t o Iowa City. The Farmington l a t e r a l , which branches off t h e main l i n e downstream of t h e pump s t a t i o n , was n o t operating, b u t was under a s t a t i c pressure. The remotely operated valve t h a t i s o l a t e s the l a t e r a l located a t the pump s t a t i o n was in t h e open p o s i t i o n whether product was being delivered t o t h e Farmington terminal o r north t o the Iowa City terminal or both. Therefore, the - - 1/ For more d e t a i l e d informati.on read "Pipeline Accident-Mid-America P i p e l i n e System Liquefied Petroleum Gas P i p e l i n e Rupture and F i r e , Donnellson, Iowa, August 4, 1978" (NTSB-PAR-79-1). 2460-B#

Page 2- 2 - s t a t i c pressure on t h e lateral was almost the same a s the discharge pressure of the pump s t a t i o n except f o r l i n e elevation differences. Because of these operating conditions, the dispatcher a t t h e Tulsa c o n t r o l center did not a n t i c i p a t e t h a t there was a problem i n t h e system when he f i r s t received information of a pressure drop a f t e r t h e pipe ruptured. If the valve t h a t i s o l a t e s t h e Farmington l a t e r a l had been closed a t the t i m e of the accident, the dispatcher would have known almost immediately t h a t t h e pressure drop was on the l a t e r a l and was not due to operating conditions i n t h e main l i n e . This information would have enabled t h e dispatcher to i n i t i a t e an emergency response s h o r t l y b e f o r e midnight instead of 12:23 a . m . ; i n another accident t h i s t i m e d i f f e r e n c e might prevent a catastrophe. Since t h i s accident, W C 0 has established a policy t h a t t h e i s o l a t i o n valve f o r t h e Farmington lateral a t t h e Birmingham Junction pump s t a t i o n be closed when product is not moving through t h i s lateral. The rupture i n t h e p i p e l i n e was approximately 33 inches long and o r i g i n a t e d on t h e west s i d e of the l i n e . It propagated l o n g i t u d i n a l l y about 17 inches and then s p i r a l l e d over 360 degrees at each end and stopped. Close examination of t h e outside surface showed gouge marks along and on e i t h e r s i d e of t h e f r a c t u r e . The most severe gouge was approximately 7 1/2 inches long and 1 / 4 inch wide and w a s located along the bottom s i d e of t h e f r a c t u r e . The depth of the gouge was approximately 0.005 t o 0.007 inch. Metallographic examination a l s o indicated t h a t the pipe had been dented. MAPCO records and o t h e r d a t a showed t h a t no excavation a c t i v i t i e s o t h e r than t h e lowering of t h e p i p e l i n e had been undertaken by e i t h e r t h e company OT by others a t t h e rupture area. This i n d i c a t e s t h a t t h e damage was done between t h e t i m e t h e pipe w a s manufactured and t h e t i m e t h e p i p e l i n e was constructed. Even though t h e damaged s e c t i o n wasr e l a t i v e l y small and would have been d i f f i c u l t to d e t e c t with t h e naked eye, t h e pipe w a s inspected four times. The pipe was inspected at t h e steel m i l l , again when i t w a s unloaded and stockpiled near t h e right-of- way, again when it was being coated, and f i n a l l y when t h e coating was being inspected before t h e pipe was lowered i n t o t h e d i t c h . Although the small s i z e of the damage and its l o c a t i o n toward the bottom of t h e pipe would have made d e t e c t i o n d i f f i c u l t , t h e Safety Board b e l i e v e s t h a t a c a r e f u l , thorough inspection of t h e pipe during construction m i g h t have discovered t h e damage.#

Page 3Three months before t h e accident, MAPC0 completed lowering a s e c t i o n of the Farmington l a t e r a l under Highway 2 adjacent t o t h e accident site. Because of the widening of the highway and the depth of the drainage ditches on each s i d e of t h e road, i t was necessary t o lower t h e p i p e l i n e more than 11 f e e t . In order t o obtain enough s l a c k i n the p i p e l i n e t o lower it t h i s much, t h e company's "rule of thumb" p r a c t i c e required t h a t f o r every foot t h e 8-inch s t e e l pipe w a s t o be lowered, a 35-foot-long s e c t i o n had t o be exposed. MAPCO and contractor personnel excavated a trench 237 f e e t from t h e n o r t h s i d e of t h e highway along t h e pipeline. Approximately every 30 f e e t , t h e crew l e f t a column of d i r t under t h e p i p e l i n e f o r support. It was l a t e r determined t h a t MAPCO had s t a r t e d lowering t h e p i p e l i n e 15 f e e t from where t h e r u p t u r e occurred and t h e pipe e l e v a t i o n had changed 10 f e e t along 170 f e e t of pipe from t h a t p o i n t . The crew then c u t south across t h e highway and dug a trench exposing t h e p i p e l i n e f o r another 290 feet. The p i p e l i n e was then reportedly lowered slowly and allowed t o follow t h e contour of t h e trench. The trench was then b a c k f i l l e d and compacted. Additional casing was added t o t h e o r i g i n a l casing on the s e c t i o n of p i p e l i n e a c r o s s the highway before b a c k f i l l . The p i p e l i n e was n o t operating a t the time t h e l i n e was lowered; however, it did have a s t a t i c pressure of 200 t o 250 psig. Therefore t h e National Transportation Safety Board recommends t h a t the Mid-America P i p e l i n e System: Determine by a n a l y t i c a l means the stresses produced on t h e pipe s t e e l when p r o j e c t s r e q u i r e t h e lowering of a s e c t i o n of p i p e l i n e , and design a s a f e t y f a c t o r t o i n s u r e t h a t t h e s e stresses w i l l n o t a f f e c t the i n t e g r i t y of t h e l i n e . (Class 11, P r i o r i t y Action)(P-79-2) E s t a b l i s h w r i t t e n procedures t h a t r e q u i r e its personnel t o a s c e r t a i n t h a t precautions are taken i n t h e f i e l d t o eliminate excessive o r sudden changes i n e l e v a t i o n when lowering a s e c t i o n of p i p e l i n e . (Class II, P r i o r i t y Action)(P-79-3) Emphasize t o i t s p i p e l i n e construction inspection personnel t h e importance of c a r e f u l , thorough inspection t o minimize t h e occurrence of d e n t s and gouges which could r e s u l t i n s i m i l a r accidents. (Class 11, P r i o r i t y Action)(P-79-4)#

Page 4- 4 - Check all other segments of its pipeline for conditions similar to the open valve condition in the line section involved in this accident and make changes or additions as required. (Class 11, Priority Action)(P-79-5) KING, Chairman, DRIVER, Vice Chairman, McADAMS and HOGUE, Members, concurred in these recommendations.#