NTSB Safety Recommendation Letter P-83-011

Page 1Official PDF9’- 2 0 I c- NATIONAL TRANSPORTATION SAFETY BOARD 1’ hs{ . i WASHINGTON, D.C. ISSUED: March 24, 1983 Dr. Henry R. Linden President Gas Research Institute 8600 West Bryn Mawr Avenue Chicago, Illinois 60637 \ SAFETY RECOMMENDAT I ON (SI ............................................. On Ocfober 29, 1982, Washington Gas Light Company dispatched a three-person crew, consisting of a crew leader, a crew mechanic, and a helper mechanic, to make three service line extensions in a new housing development at Burke, Virginia. The extensions were to be made without shutting off the flow of gas in the main. About 10:30 am., the crew arrived at the work site and connected the service line for residence No. 10027 (see figure 1) to an existing service line stub. After making this connection, the crew was to install a branch service line to residence No. 10023 from the service line connected to the house next door, No. 10025. Using hand tools, a hole 30 inches deep was excavated to expose the plastic service line. The service line was cut, and the end of the service line segment which contained gas under pressure was sealed with a cap. The installation required that a branch tee connection be installed in the service line to No. 10025 to allow No. 10023 to be served from the same service line. A check of the service truck disclased that the appropriate compression tee was not available at the job site; by radio, the crew leader called the foreman and advised him that a branch tee w a s needed. While waiting for the requested fitting, the crew began work at residence No. 10002. When the foreman arrived with the branch tee, the crew mechanic volunteered to install t h e tee on the service line to No. 10025. Neither the foreman nor the crew leader advised against this action, and the crew leader and helper mechanic continued working at residence No. 10002. After a few minutes, the crew leader looked up and did not see the crew mechanic. H e walked to No. 10025 and found the crew mechanic face down inside the excavation with gas escaping at 1 8 psig from the service line. He pulled the crew mechanic from the excavation and tried to revive him by calling his name and slapping his face. When this action did not revive the crew mechanic, the crew leader ran to his truck and called the gas company dispatcher. Meanwhile, the helper mechanic arrived at the excavation site. Both the crew leader and the helper mechanic had attended company cardiopulmonary resuscitation (CPR) training, but neither attempted to use this means to revive the crew mechanic. About 4 to 5 minutes later, a rescue squad arrived and, after attempting to revive the crew mechanic, transported him to the hospital, where he was declared dead. After removing the crew mechanic from the excavation, the crew leader and helper mechanic noticed that the compression tee was partially installed. One downstream connection was completed; the other downstream connection had been made, but the retaining nut was only hand-tight. The upstream connection had not been made, and the cap had been removed from the portion of the service line under pressure. Company 3678#

Page 2procedures allow work to be performed on lines containing gas under pressure, and for the ( installation being undertaken, a pressure up to 55 psig was permissible. Company procedures also require that (1) as a means to reduce the time an employee works in hazardous environment, the nonpressurized connections be completed the line under pressure is removed for making the final connectio performing work on lines containing gas under pressure, at least two present, with one observing the work and available to rescue the employ work if necessary. Company records reflect that each crewmember had received a comb on-the-job and classroom training sufficient to qualify him to perform in accordance with company procedures. The company evaluates the effec classroom training through an employee testing program. Employee actions in this accident demonstrate that these crewmem follow company procedures and did not apply training received - ~ (1) the c the crew mechanic both failed to comply with the requirement that two employees be present when working on lines containing gas under pressure; (2) the cre not follow explicitly the installation procedures for installing the compression tee; and ( neither the crew leader nor the helper mechanic attempted to revive the crew mechan by employing CPR techniques. This death could have been prevented had a secon employee been present while the compression tee was being installed, a may have been prevented had the compression tee installation procedures been followed explicitly. In a 1981 Special Study,&/ the Safety Board characterized many con which the installation of excess flow valves21 appear to have safety p recommended that the Gas Research Institute (GRI): Determine the conditions and locations (other than those for which the Safety Board is recommending immediate regulatory action--Le., pressure, single-family residential services) for which excess flow v can be effective in preventing or minimizing the potential for types of accidents resulting from leaks on high and low pressure service lines. Among the conditions which should be evaluated are gas demand variations, minimum operating pressure, service line size, length, and configuration, major leaks on house piping, cleanliness of gas, and effect of peak shaving operations. (P-81-36) In response to this recommendation, the GRI has instituted a rese which, as one of its 1983 objectives, will identify situations in which ex are cost-effective. Recognizing that the cause of this accident was practices, the Safety Board believes that this accident might have been prevented if excess flow valve had been installed in the service lines. The Safety Board also belie that the previously unidentified potential for excess flow valves to prev when work is being performed on gas pipelines should be included as a part o project for assessing the cost-effectiveness of excess flow valves. - 1/ Pipeline Special Study: "Pipeline Excess Flow Valves" National Transportat Board, September 9,1981, (NTSB-PSS-81-1). - 2 1 An excess flow valve is a safety device installed on the service line near its with the gas main to automatically and rapidly shut off the flow of gas in the service line rupture. These devices are not required by Federal safety stand#

Page 3-3 - Accordingly, the National Transportation Safety Board recommends that the Gas Research Institute: Include within its ongoing research for assessing the cost effectiveness of excess flow valves, an assessment of the potential for such valves to prevent or minimize the effect of accidents which may occur while work is being performed on the system by gas company employees. (Class E, Priority Action) (P-83-11) The National Transportation Safety Board is an independent Federal agency with the statutory responsibility "...to promote transportation safety by conducting independent accident investigations and by formulating safety improvement recommendations." (P.L. 93-633). The Safety Board is vitally interested in any actions taken as a result of our safety recommendations. Therefore, we would appreciate a response from you regarding action taken or contemplated with respect to the recommendation in this letter. BURNETT, Chairman, GOLDMAN, Vice Chairman, and McADAMS, BURSLEY, and ENGEN, Members, concurred in this recommendation. im Burnett#

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