NTSB Safety Recommendation Letter P-78-076 through P-78-078

Page 1Official PDFP- I / 04 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. I S S U E D : December 29, 1978 Forwarded t o : \ M r . T. M. Torson President Torson Construction Company 9222 E a s t 47th S t r e e t Kansas City, Missouri 64133 SAFETY RECOMMENDAT I O N ( i ) P-78-76 through -78 A t 1:30 p.m., c.d.t., on June 12, 1978, a 10-inch natural gas p i p e l i n e owned by the Gas Service Company (gas company) was s t r u c k and ruptured by excavation equipment during construction of a sewer i n Kansas City, Missouri. The n a t u r a l g a s , a t more than 110-psig pressure, escaped from a 5-inch-long hole i n t h e pipeline. A t 3:15 p.m., t h e gas i g n i t e d while two gas company employees were cleaning t h e pipe with hand t o o l s before i n s t a l l i n g a pipe r e p a i r clamp. Both men were burned seriously. 3J One week before t h e accident, a g a s company inspector had accurately located t h e p i p e l i n e with an e l e c t r o n i c pipe l o c a t o r . He placed two yellow location f l a g s over i t , 75 f e e t a p a r t , one on each s i d e of the sewer easement. On t h e day of t h e accident, t h e Torson Construction Company (contractor) planned t o grade the sewer easement i n t h e area where t h e plans showed t h e sewer crossing t h e pipeline. About 7 a . m . , t h e contractor's superintendent i n s t r u c t e d an equipment operator t o d i g a 5-foot-deep and 15-foot-wide "bench" along the c e n t e r l i n e of t h e sewer with a l a r g e d i e s e l C a t e r p i l l a r t r a c t o r , Model 977 Highloader, from which a medium-size backhoe could excavate down t o t h e planned 20-foot depth of t h e sewer. The equipment operator w a s shown t h e l o c a t i o n f l a g on t h e east s i d e of t h e sewer right-of-way but not t h e other l o c a t i o n f l a g or t h e permanent p i p e l i n e markers, which were p a r t l y obscured by weeds on t h e p i p e l i n e right-of-way. - 11 For more d e t a i l e d information read "Pipeline Accident Report -- The Gas Service Company Natural Gas Pipeline Rupture and F i r e , Kansas City, Missouri, June 1.2, 1978" (NTSB.-PAR-78- 5 ) . 2533#

Page 2- 2 - A t 11:30 a . m . , t h e superintendent c a l l e d t h e gas company and asked how deep t h e p i p e l i n e w a s buried a t t h e crossing. The gas company engineer taking t h e c a l l s a i d t h a t although t h e company's newer p i p e l i n e s are buried about 30 inches deep, he d i d n o t know t h e exact depth of the 48-year-old pipe:line. He-suggested t h a t t h e superintendent t a l k t o t h e gas company dispatcher and request t h a t an inspector be s e n t t o t h e j o b s i t e t o determine the exact depth. The superintendent did n o t c a l l t h e dispatcher as recommended because a large backhoe, the primary piece of excavating equipment, w a s being used more than 100 f e e t from t h e c r o s s i n g , and would n o t a r r i v e at t h e crossing t h a t day. About 2 hours later, t h e highloader s t r u c k and ruptured the p i p e l i n e at a depth of 2 4 inches. The construction s p e c i f i c a t i o n s s t a t e d t h a t i t was t h e c o n t r a c t o r ' s s e s p o n s i b i l i t y t o "verify t h e l o c a t i o n , elevation, and dimensions of a l l known or suspected underground obstructions ahead of t h e work . . . ." The gas company had located its p i p e l i n e twice before t h e accident. The f i r s t t i m e was on Xarch 15, 1978, when i t exposed t h e p i p e l i n e t o i n s t a l l weld reinforcement s l e e v e s . The second time w a s on June 6 , 19'78, when t h e gas company staked t h e l i n e . Each t i m e , t h e contractor and the gas company could have begun t o coordinate t h e i r ' a c t i v i t i e s and t o e s t a b l i s h t h e exact l o c a t i o n and cover of t h e pipeline. When t h e gas company excavated t h e p i p e l i n e and i n s t a l l e d t h e weld reinforcement s l e e v e s , t h e contractor should have marked t h e exact l o c a t i o n and cover of t h e p i p e l i n e f o r f u t u r e reference. A long delay i n b a c k f i l l i n g provided ample opportunity f o r t h e contractor e i t h e r t o measure t h e 24-inch p i p e l i n e depth and l o c a t e t h e p i p e l i n e o r t o arrange t o have the gas company i n s t a l l temporary p i p e l i n e markers over the p i p e l i n e . The delay i n b a c k f i l l i n g a l s o provided t h e consulting engineer ample time t o determine p r e c i s e elevations on t h e exposed p i p e l i n e and change t h e p r o f i l e drawings t h a t showed t h e erroneous 3 1/2-foo.t cover measurement. Apparently, t h e r e was a lack of communications 'between the operator and t h e superintendent as t o how close t h e highloader should come t o t h e pipeline. The superintendent had placed an i r o n s t a k e on t h e c e n t e r l i n e of t h e aewer approximately a t t h e p i p e l i n e crossing and s a i d t h a t h e had toad t h e equipment operator on t h e highloader t o s t o p 5 f e e t before t h e stake. The equipment operator s a i d t h a t he thought h i s i n s t r u c t i o n s were t o excavate up t o t h e s t a k e . A labor helper or line s p o t t e r standing over t h e p i p e l i n e could have kept t h e bucket 5 f e e t from t h e p i p e l i n e l o c a t i o n . An even b e t t e r way of p r o t e c t i n g t h e p i p e l i n e would have been t o d i g test holes over t h e gas p i p e l i n e t o determine its exact h o r i z o n t a l and v e r t i c a l l o c a t i o n s , as c a l l e d f o r i n t h e construction s p e c i f i c a t i o n s .#

Page 3- 3 - Therefore, the National Transportation Safety Board recommends t h a t the Torson Construction Company: P r o t e c t pipelines t o be crossed during construction by v e r i f y i n g the l o c a t i o n , e l e v a t i o n , and dimensions of a l l known or suspected underground obstructions ahead of the work and by reviewing a l l requirements i n the specifica- t i o n s with i t s f i e l d supervisor. (Class 11, P r i o r i t y Action) (P-78-76) E s t a b l i s h an e a r l y l i a i s o n with the gas company before commencement of construction p r o j e c t s and coordinate the f i e l d a c t i v i t i e s of the construction crews t o afford maximum p r o t e c t i o n of p i p e l i n e f a c i l i t i e s . (Class 11, P r i o r i t y Action) (P-78-77) Require its employees t o p r e c i s e l y e s t a b l i s h t h e h o r i z o n t a l and v e r t j c a l l o c a t i o n s of gas p i p e l i n e s by means of hand-excavated test holes before allowing heavy excavation equipment i n t h e a r e a of a p i p e l i n e crossing. (Class 11, P r i o r i t y Action) (P--78-78) RWG, Chairman, DRIVER, Vice Chairman, McADAMS and HOGUE, Members, concurred i n the above recommendations.#