Special Study

Special Study of Effects of Delay in Shutting Down Failed Pipeline Systems and Methods of Providing Rapid Shutdown

NTSB Number: PSS-71-1
Adopted: December 30, 1970

Honorable ,John A. Volpe
Secretary of Transportation
400 Seventh Street, S. W.
Washington, D. C. 20590

Dear Mr. Secretary:
The National Transportation Safety Board has recently conducted a study entitled, "The Effects of Delay in Shutting Down Failed Pipeline Systems and Methods of Providing Rapid Shutdown. "

In many recent pipeline accidents, a delay in promptly shutting down the failed pipeline system has magnified the effects of the accident. The study points out that by reducing the time between failure and shutdown, the accident effects can be minimized or eliminated. Equipment and procedures, which could have prevented the accidents discussed in the study if they had been employed, are currently available and in use by some pipeline operators on a limited basis. The study discusses in general terms some of the methods and types of equipment that are available to the industry at present to obtain rapid shutdown of failed facilities. The equipment is quite varied, ranging greatly in complexity and in cost.

Use of the rapid shutdown equipment and plans vary greatly within the gas and liquid pipeline industries, mainly because there are no industry guidelines or Federal requirements as to what constitutes a reasonable period of time between a failure and a shutdown.

The need for such Federal regulation is pointed out by the fact that the current regulations would not have prevented any of the tragic accidents referred to in the study.

The study also discusses the degree of security to be provided to the public.

On the basis of the study, the National Transportation Safety Board recommends that:

The Office of Pipeline Safety of the Department of
Transportation conduct a study to develop standards
for the rapid shutdown of failed natural gas pipelines
and work in conj unction with the Federal Railroad
Administration to develop similar standards for liquid

The purpose of the rapid shutdown is to reduce the amount of hazardous materials released, and any method which will quickly reduce the amount released should be considered.

The degree of security provided by the standards should also consider the relative hazard of the commodity, the size of the popu1ation-at-risk at points along the pipelines, and the potential damaging effects on property and the environment. Two special factors concerning the population-at-risk should be taken into account; namely, (1) that in most situations the risk is concentrated in the relatively small proportion of the population near pipelines, whereas the remainder of the population benefits with lesser risk from the use of the commodities, and (2) that the population-at-risk is often unaware of the hazard and therefore unable to escape it or guard against it, and is dependent upon the protection of the regulations. The risk to those near pipelines should not be appreciably greater than the risk to the remainder of the population. A substantially greater effort to protect those near pipelines should be provided than would be justified by balancing the cost of safety measures against the lives to be saved.