NTSB Safety Recommendation Letter P-78-041 through P-78-042

Page 1Official PDFNATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. i Forwarded to: M r . Charles F. Riddick Manager, ALDLY Pipeline Systems E . I . du Pont de Nemours & Co.(Inc.) Wilmington, Delaware 19898 P-78-41 and -42 i P l a s t i c Products and Resins Department ......................................... A t 12:5D a.m., c . s . ~ . , on December 15, 1977, a 2-inch p l a s t i c gas main under an a l l e y i n downtown Lawrence, Kansas, pulled out of a compression coupling which joined i t to a steel gas main. Natural gas escaped from the main and migrated through the stone foundation w a l l s of two nearby buildings. A t 1:20 a . m . , the accumulations of gas i n t h e two buildings i g n i t e d . The r e s u l t i n g explosion and f i r e destroyed one building, severely damaged t h e other building, and broke nearby windows. Two persons were k i l l e d and t h r e e persons were injured. - 1/ The 394-foot-long polyethylene p l a s t i c gas main had been i n s e r t e d i n an abandoned 3-inch steel main on June 2, 1975. It was connected t o a s t e e l gas main with a Dresser S t y l e 90 short-barrel compression coupling. Du Pont provided the 5-inch-long smooth s t e e l s t i f f e n e r t h a t w a s used i n s i d e of t h e end of t h e p l a s t i c pipe. Both products individually conformed to t h e requirements of 49 CFR 192.281(e). However, t h e composite j o i n t was not a s strong a s t h e p l a s t i c pipe being joined as required by 49 CFR 192.281(a). The Dresser S t y l e 90 i n s t a l l a t i o n i n s t r u c t i o n s a r e sent i n t h e boxes of f i t t i n g s and contain a warning t h a t proper anchoring of t h e pipe should be provided. A s i m i l a r appropriate warning a g a i n s t pullout could be incorporated i n t h e Du Pont boxes of s t i f f e n e r s . There a r e many tests being conducted by t h e American Gas Association and the Society of t h e P l a s t i c Industry, Inc., on such areas as t h e e f f e c t s of temperature on polyethylene p l a s t i c pipe. Du Pont undoubtedly has conducted additional tests t h a t a l s o could be of b e n e f i t t o the gas industry t o which it supplies l a r g e q u a n t i t i e s of p l a s t i c pipe. Based on t h e tests t h a t the National Bureau of Standards conducted on t h e j o i n t t h a t f a i l e d , t h e Safety Board has determined t h a t a d d i t i o n a l tests on t h e e f f e c t t h a t time has on t h e pullout r e s i s t a n c e of polyethylene p l a s t i c pipe and standard compression couplings a r e warranted. - 1/ For more d e t a i l e d information read "Pipeline Accident Report -- Kansas Public Service Company, Inc., Explosion and F i r e , Lawrence, Kansas, December 15, 1977 ,I' (NTSB-PAR-78-4). 2386#

Page 2- 2 - Therefore, the National Transportation Safety Board recommends that the E.I. du Pont de Nemours & Company: Enclose warning literature and installation instructions in each carton of internal stiffeners indicating that the stiffeners do not provide any anchoring properties, and that it is the gas company's responsibility t o properly design and install plastic pipelines in accordance with the applicable provisions of 49 CFR 192. (Class 11, Priority Act ion) (P-7 8-41) Work with the American Gas Association and the Society of the Plastic Industry, Inc., to conduct tests to determine the effect of time on the pullout resistance of polyethylene plastic pipe and standard compression couplings. (Class 111, Longer Term Action)(P-78-42) KING, Chairman, McADAMS, HOGUE, and DRIVER, Members concurred in the above recommendations.#