NTSB Safety Recommendation Letter P-74-037 through P-74-049

Page 1Official PDF- 26 - Contributing t o the accident was the lack of odor i n the leaked gas when i t reached the houses and the atmosphere. RECOMkENDATZONS The National Transportation Safety Board recomends that: 1. The Office of Pipeline Safety of the Department of Transportation: 2. 3 . 4 . (a) Require pipeline operators who use materials not s p e c i f i c a l l y covered i n the Federal regulations to formally advise the Department of Transportation of its use. (Recomendation No. P-74-37) @) I n i t s study of p l a s t i c pipe, determine whether occluded par- t i c l e s d u r i n g extrusion are a significant safety problem, and, i f so found, take necessary regulatory action t o control t h a t problem. (Recommendation No. P-74-38) The Department of Housing and Urban Development: (a) Study the flow of natural gas through various basement wall and floor materials and through various types of construction. The study should include e f f e c t i v e methods of sealing the space around underground u t i l i t y l i n e s and ducts where they enter a building, and methods of permitting gas t o escape i n the open atmosphere when conducted t o these entrance areas. (Recomenda- t i o n No. 74-39) The American Society of Mechanical Engineers Gas Piping Standards Cormnit tee: (a) Develop guidelines t o a s s i s t pipeline operators t o maintain adequate public protection i n areas where odorant adsorption by s o i l could occur. (Recommendation No. P-74-40) (b) Develop g u i d e l i n e s for t h e sampling of combustible gases t o assure proper concentrations of odorant as required by 49 CFR 192.625(f). @ecormnendation No. P-74-41) (c) Develop guidelines t o assist pipeline operators i n training meter readers and others who work at customers' premises t o detect vegetation areas t h a t might be a n i n d i c a t i o n of gas leakage. (Recommendation No. P-74-42) The American Gas Association: (a) Give a high p r i o r i t y t o the problem of s o i l adsorption of odor- a n t compounds i n i t s planned research t o develop an improved odorant. (Recommendation No. P-74-43)#

Page 2- 27 - @) Give consideration t o measuring the odorant level of gas escap- ing from underground leaks i n its planned research on odorant monitoring. (Recowlendation No. P-74-44) (c) Develop methods of t e s t i n g s o i l s t o determine the p o t e n t i a l e f f e c t on odorants. (Recommendation No. P-74-45) Study the natural gas permeating and migration phenomena i n var- (d) Based on the re- ious types of s o i l and under paved surfaces. s u l t s of t h i s study, recommend the use of c e r t a i n types of s o i l for pipeline b a c k f i l l material t h a t w i l l aid i n allowing leaking gas t o vent to the atmosphere a t the leak location with a mini- mum permeation or migration e f f e c t . (RecommendationNo.P-74-46) 5 The National F i r e Protection Association: (a) Advise f i r e f i g h t i n g personnel of the phenomenon of adsorption of gas odorant compounds by c e r t a i n types of s o i l s . They should be reminded of the need to use combustible gas indicators when a t - tempts a r e being made t o d e t e c t the presence of leaking gas. (Recommendation No. P-74-47) 6 . The Washington Gas Light Company: (a) Continue its e f f o r t s a t the accident s i t e to d i s s i p a t e the residual gas remaining i n the ground. B-7+ 9% @) Continue t o monitor and test the affected homes i n the area for the presence of gas u n t i l no further hazard from the r e s i d u a l gas is apparent. (Recommendation No. P-74-@) lJrl -1 I BY THE NATIONAL TRANSPORTATION SAFETY BOARD /s/ JOHN H. REED Chairman /s/ FRANCIS H. ElcADAElS Member / S / LOUIS M. THAYER Member .- /s/ ISABEL A. BURGESS Member /s/ WILLIAM R. HALEX Plember October 24, 1974#