[Federal Register Volume 59, Number 12 (Wednesday, January 19, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1256]


[[Page Unknown]]

[Federal Register: January 19, 1994]


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DEPARTMENT OF TRANSPORTATION
 

Pipeline Safety Advisory Bulletin ADB-94-02 Valve Location and 
Spacing

AGENCY: Research and Special Programs Administration (RSPA), DOT.

ACTION: Advisory to owners and operators of gas distribution 
facilities.

SUMMARY: The purpose of this advisory bulletin is to provide guidance 
to operators regarding the valve location and spacing requirements of 
49 CFR 192.181(a).

Advisory

    In the event of an incident or other emergency, the number and 
location of gas distribution system valves are critical in achieving 
the effective shut down and isolation of any section of main in a gas 
distribution system. The RSPA is providing guidance in this Advisory 
Bulletin to owners and operators to assure that valving on high 
pressure distribution systems complies with the requirements of 
Sec. 192.181(a).
    The ``Guide for Gas Transmission and Distribution Piping Systems'' 
(Guide) can be referred to for help in establishing locations for 
emergency valves. Developed by the Gas Piping Technology Committee, it 
is now referenced as American National Standards Institute ANSI/GPTC Z 
380. Copies are available through the American Gas Association; 1515 
Wilson Blvd.; Arlington, VA 22209.
    The guide lists the following as criteria to be considered when 
establishing valve locations in high pressure distribution systems:
     Physical Characteristics:
--Size of area to be isolated.
--Topographic features (such as rivers, major highways and railroads).
--Number of valves necessary to isolate the area.

     Operating Characteristics:
--Number of customers and type of customers such as hospitals, schools 
and commercial and industrial users that would be affected.
--Time required for available personnel to carry out isolation 
procedures.
--Time required for controlling the pressure in the isolated area by 
means of venting, transferring gas to adjacent systems, etc.
--Time required for available personnel to restore service to 
customers.

Background

    A high pressure gas main in Atlanta, Georgia was ruptured by a 
construction contractor on December 1, 1977. The National 
Transportation Safety Board (NTSB) investigated the incident and found 
the probable cause was the failure of the contractor to use information 
available to him on his blueprint which resulted in the rupture of the 
gas main. The incident occurred at 1:00 p.m. and, because of a poor 
selection of the location and the number of emergency valves, it took 
until 2:45 p.m. to shut off the flow of gas to the ruptured main.
    In its accident report on the rupture, NTSB recommended (Safety 
Recommendation P-78-24) that RSPA amend 192.181(a) to specifically 
define the requirement for location and number of emergency valves. 
This is not feasible because the location and number of emergency 
valves is dependent on local conditions, and because local conditions 
vary greatly from operator to operator and city to city. Therefore, by 
means of this Advisory Bulletin, the attention of operators is being 
redirected to the requirements of Sec. 192.181(a), and to the Guide for 
any help it can be toward meeting the requirements of Sec. 192.181(a). 
Although Sec. 192.181 is a design regulation on gas distribution 
systems readied for service after March 1971, on systems installed 
before (as well as after) that date the Guide material can be used, as 
noted previously, as a help in determining emergency valve locations.

    Issued in Washington, DC, January 13, 1994.
George W. Tenley, Jr.,
Associate Administrator for Pipeline Safety.
[FR Doc. 94-1256 Filed 1-18-94; 8:45 am]
BILLING CODE 4910-60-P