NTSB Safety Recommendation Letter P-84-017 through P-84-018

Page 1Official PDFNATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. I S S U E D : June 15, 1984 Forwarded to: Mr. Stan Mruk Technical Director Plastic Pipe Institute 355 Lexington Avenue New York, New York 10017 SAFETY RECOMMENDAT I O N ( S ) P-84-17 and -18 --^---__---____________________I________----- At 11:15 a.m., c.d.t., on July 12, 1983, natural gas escaping under 60 pounds pressure from a crack in a butt fusion joint in a 2-inch plastic gas main entered an apartment building in Clear Lake, Iowa, exploded and then burned. Two Interstate Power Company employees were injured, one apartment building was destroyed, and the adjacent apartment building was damaged heavily. Damage was estimated a t more than $1 million; none of the residents were injured or killed. - 1/ According to the Plastic Pipe Institute and plastic pipe manufacturers, such as Dupont, Plexco, and Nipak, a butt fusion between two lengths of plastic pipe when properly made, should be as strong or stronger than the plastic pipe itself. A butt weld between two lengths of steel pipe carries the same strength definition, however, here the similarity ends. In the field, accurate, reliable, repeatable, nondestructive testing of steel butt welds can be readily and practically undertaken by X-ray, radioactive isotopes (gamma rays), and magna flux. The American Petroleum Institutes (API) Standards for Welding Pipelines and Related Facilities, API Std 1104, Section 6.0, Standards of Acceptability, and Section 8.D, Radiographic Procedure, set the standards of acceptability for size and type of weld defect, the requirements for producing acceptable radiographs, and the qualifications of the radiographers for the work. Over the years, these API standards have been improved to the point that today field radiographic inspection of butt welds on steel pipes, by qualified, motivated technicians, can be classified as a science. However, the field nondestructive tests for plastic pipe butt fusion cannot be classified as a science. The physical appearance of the fusion is the primary nondestructive field test method. However, the physical appearance test is valid only when all other procedures of squaring the pipe, heating the tool, applying the pressure, and holding the pipe have been rigidly adhered to. During the annual fusion qualification tests given by Interstate to its pipefitters/operators wherein the employees' work was given a physical inspection followed by a destructive test, most of the persons passed both. However, one person's - 1/ For more detailed information, read Pipeline Accident Report-"Interstate Power Company, Natural Gas Explosion and Fire, Clear Lake, Iowa, July 12, 1983" (NTSB-PAR-84/02). 3762-A#

Page 2-2- work passed the visual inspection, but failed the destructive test; one per both the visual inspection and the destructive test; and one person inspection and passed the destructive test. Interstate stated that all persons had to pass both aspects (visual inspection and destructive testing) before being allowed to fu plastic pipe in actual field operation. The Safety Board is concerne appearance of a butt fusion joint is more of an art than a science and tha to one supervisor may not look good to another and, indeed, upon destructive testing, ma fail. As to the July 12, 1983 accident, the report prepared by the testing laborator stated that the external appearance of the failed butt fusion joi fusion weld wherein uniform fusion of the plastic pipe surfaces had no around the pipe. The findings in this accident raise the question abo plastic butt fusion joints which may have been installed and have a good exter appearance, but which in fact, may be substandard. U.S. Department of Transportation data for the past year includes only one that has been attributed to joint failure in plastic pipe; however, the pipeline accidents does not have a specific category for joint failure. Accidents involving joint failure in plastic pipe are reported under the "other" category, and joint failure may or may not be specified. Therefore, it is unlikely that the statistics a the true number of plastic pipe joint failures. A t least two other stress possibilities were present in this acci joint was placed in a bend in the pipe (the bend was not measu when the pipe was excavated) and that subjected the weld to construction activity was conducted in the vicinity of the pipe after i (a sidewalk was laid over it, a swimming pool was constructed close to it, and a p lot was built close to it). All of the construction activity was conducted with loaded with material operating close to the pipe. These stresses may the fusion failure, however, if the fusion had been 'I.. .as strong or stronger than t h plastic pipe itself," the bend and construction activity should not have affected it and th accident may not have occurred. On December 30, 1970, the Safety Board issued "Special Study of Effects of Delay Shutting Down Failed Pipeline Systems and Methods of Shutdown." 2/ Since then the Board has issued 33 safety recommend 16 pipeline gccident which involved failure to shut down pipelines in t h e Introduction to the Special Study, the Safety Board stated: In almost all recent pipeline accidents, the delay in shutting failed pipeline system has resulted in an increased catastrophe. Had the flow of gas or hazardous liquid been stopped so0 after the initial rupture, the effects of many accidents would have bee minimized or eliminated. With the ever increasing use natural gas and other hazardous materials and the proximity of thes lines to expanding populated areas, it is imperativ methods be developed and put to use which will provi shutting down of failed pipeline systems. The Safety Board concluded that: - 2/ Special Study of Effects of Delay in Shutting Down Failed PipMethods of Providing Rapid Shutdown (NTSB-PSS-71-1).#

Page 3-3- By reducing the time required to shut down a failed pipeline system to minimize the loss of material, the hazardous effects to the public, to persons working near a pipeline, and to property can be minimized or eliminated. Equipment and procedures are currently available which, if utilized, could drastically reduce the shutdown delay cited in the accidents discussed in this study. The Clear Lake accident is another illustration of the unfortunate consequences when failed pipeline facilities are not shut down in a timely manner. While Interstate has a formal, written plan for shutting down its gas facilities, the plan does not address specifically the rapid shutdown of small sections of pipeline, such as the one involved in this accident. Moreover the plan is given only to supervisory personnel and not to the employees who are the first to be dispatched to a gas leak site. As a result of its investigation of a pipeline accident in Annandale, Virginia, on March 24, 1972, in which three persons died, one person was injured, two houses were destroyed, and a third house was badly damaged, 3 / the Safety Board recommended that the Office of Pipeline Safety (now the Research aEd Special Programs Administration) of the U.S. Department of Transportation: Amend 49 CFR 192 to require that each operator maintain a log which shows the receiDt and handline of each leak or emereencv reDort performance in responding to gas leak emergencies and reports; Both the logs and the analysis should be made available to State agencies and the Office of Pipeline Safety. (Safety Recommendation P-72-42) (emphasis added) It is important for gas companies to encourage reporting and to maintain an effective line of communication with the public since the public is the best source for reporting most gas odors/gas leaks. An effective leak response system must include the immediate logging of telephone calls about gas odors, the logging of the precise information given (date, time, location, and leak description), and the rapid dissemination of this information to the responding crew. Emergency-type telephone calls should have the highest priority and should be handled completely before attention is given to regular business matters. By so doing, the gas company not only can insure the rapid response to a complaint, but it can check on its own efficiency as to when the crew was dispatched, when the crew arrived, what conditions the crew encountered, and when the condition was rendered safe. Many gas companies tape record all incoming emergency-type telephone calls as a matter of record and as a means to assess their dispatching efficiency. Unfortunately, in this accident, there was no record of t h e first or second telephone calls from the apartment resident who reported the gas odor, no work order was printed giving the particulars of the leak in time for the serviceman to take with him when he responded, and there was no accurate record of the time the serviceman arrived a t the leak site. Undisciplined handling of gas odor or gas leak telephone calls, as was apparent in this accident, decreases the speed and effectiveness in the response to those calls. - 3/ Pipeline Accident Report--"Washington Gas Light Company Natural Gas Explosions at Annandale, Virginia, March 24, 1972 '' (NTSB-PAR-72-4).#

Page 4-4- Since October 14, 1970, the Safety Board has issued 88 pip recommendations to the pipeline industry and to the Research and Spec Administration of the U. S. Department of Transportation regarding the development written emergency procedures to be implemented during pipeline emergencies. Thes recommendations have addressed a range of suggestions from the receipt and rapi processing of telephone calls reporting g to the accident site, the ventilation of from buildings, to the rapid shutdown of t twofold: first, a gas company must have gas company employees who may be called upon to respond to emergencies must b familiar with these emergency plans to implement them consistent effectively. Therefore, the National Transportation Safety Board recommends that tf Pipe Institute: Urge its member companies to emphasize to users of plastic pipes t importance of explicitly following recommended fusion (Class 11, Priority Action) (P-84-17) Urge its member companies to cooperate with the Gas Research Institute in the development of nondestructive equipment testing capable of detecting inadequately fused butt, saddle, and socket fusion joints in the field. (Class II, Priority Action) (P-84-18) The National Transportation Safety Board is an independent Federal agency with t h statutory responsibility 'I. . .to promote transportation safety by conducting independe accident investigations and by formulating safety improvemelit recommendations" (P.L. 93-633). The Safety Board is vitally interested in any actions taken as a result of its safety recommendations and would appreciate a response from you regarding action taken or contemplated with respect to the recommendations in this letter. BURNETT, Chairman, GOLDMAN, Vice Chairman, and BURSLEY and G Members, concurred in these recommendations.#