NTSB Safety Recommendation Letter P-76-043 through P-76-047

Page 1Official PDFAL TWANSPO TATION SAFETY BOA WASHINGTON, D.C. I S S U E D : S e p t e m b e r 15, 1976 Honorable W i l l i a m T. Coleman, Jr. Secretary SAFETY RECOMMENDATION(S) Department of Transportation Washington, D. C. 20590 P-76-43 through P-76-47 A t 9:32 a.m. on January 10, 1976, gas which was leaking into the Pathfinder Hotel i n Fremont, Nebraska, ignited. The gas was leaking from a 2-inch plastic pipe which had pulled out of its com- pression coupling; the gas seeped into the hotel because it had been capped above by frozen earth and a concrete road surface. ?he hotel exploded and f i r e ensued; the explosion and f i r e destroyed the hotel, damaged nearby buildings, and broke windows w i t h i n a one-block radius. Thirty-nine persons were injured and 20 persans were killed. - 11 A 348-foot-long 2-inch plastic m i n was inserted in an existin % 4-inch steel main on June 26, 1974, when the a i r temperature was 86 F and the minirmw ground temperature was interpolated from engineering handbooks to be 600F. A t the tirre of the accident, the g r m d tem- perature was 36OF. This 24OF temperature change caused the pipe t o contract. If the pipe had been unrestrained, it could have contracted up t o 9% inches the f i r s t year. Hmever, the seven service lines attached t o it and the restraints of the compression coupling allowed the plastic pipe t o mve only 1% inch within one of the couplings during the f i r s t winter after installation. k i n g the second win- ter, the plastic pipe pulled completely out of this coupling, which was in front of the hotel, and caused the accident. The gas company used a smooth metal stiffener inside the pipe instead of the proprietary serrated lock stiffener -which was made by - 11 For mre detailed infomation on this accident, read 'Tipeline Accident &port -- Nebraska Natural Gas Cxmpany, Pathfinder Hotel Explosion and Fire, F r m t , Nebraska, January 10, 1976." NTSB- PAR-76-6 ~ 174l.A#

Page 2the manufacturer of the compression coupling The resulting combina- tion produced a joint which was not as strong as the plastic pipe which was being joined When the plastic pipe pulled out of the compression coupling. gas migrated into the hotel and ignited Because two of the three s e r v i c m who were on call for the weekend were away from their telephones, there was an exceptionally long delay of 1 hour before the gas company could respond to the emergency Therefore, the National Transportation Safety Board recarmends that the Department of Transportation: Study the plastic-to-steel transition nroblems and take appropriate regulatory action to correct any unsafe practices. (P-76-43) (Class 11, Priority Followup) Revise 49 CFR 192 281(e) (2), 'Mechanical Joints," to re- quire t h a t stiffeners be designed to be compatible with compression couplings so that pipes cannot p u l l out of the couplings (P-76-44) (Class 11, Priority Followup) Determine if there are locations or circumstances where standard compression couplings are unsafe, and amnd 49 CTR 192 accordingly to prohibit their use for such appli- cations. (P-76-45) (Class 11, Priority Followup) Analyze the methods which operators use to receive and respond to emergency calls and, based upon this analysis, 1 , amend 49 CFR 192, "Operations, to specify m i n h accept- able standards (P-76-46) (Class 11, Priority Follawup) Amend 49 CFR 192, "Operations ," t o require that operators record the receipt of emergency calls, the response to the calls, and the time of each significant action taken by the operator (P-76-47) (Class 11, Priority Followup) K D D , C h a i m , I?cAlMG, HCCXJE, BURGESS, and HkLEY, Members, concurred in the above recomrEndati#