08-999. Pipeline Safety: Dangers of Abnormal Snow and Ice Build-Up on Gas Distribution Systems

AGENCY:

Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT.

ACTION:

Notice; Issuance of Advisory Bulletin.

SUMMARY:

Recent events on natural gas distribution system facilities appear to be related to either the stress of snow and ice or malfunction of pressure control equipment due to ice blockage of pressure control equipment vents by ice. This advisory bulletin advises owners and operators of gas pipelines of the need to take steps to prevent damage to pipeline facilities from accumulated snow or ice.

FOR FURTHER INFORMATION CONTACT:

Alan Mayberry at [phone], or by e-mail at [e-mail].

SUPPLEMENTARY INFORMATION:

I. Background

The accumulation of snow and ice increases the potential for damage to meters and regulators and other pipeline facilities. Several accidents occurring during the winter of 2007/2008 on natural gas distribution system facilities appear to be related to either the stress of snow and ice or malfunction of pressure control equipment due to ice blockage of pressure control equipment vents. Exposed piping at metering and pressure regulating stations, at service regulators, and at propane tanks, are at greatest risk. Damage may result from the stresses imposed by the additional loading of the snow or ice. Damage to facilities may also result from the impact of snow or ice falling from roofs, or ice forming in or on regulators preventing their proper operation, or shoveling snow from roofs to protect dwellings from abnormal snow accumulation.

II. Advisory Bulletin (ADB-08-03)

To: Owners and Operators of Petroleum Gas and Natural Gas Facilities in Areas Subject to Heavy Snowfall or Abnormally Icy Weather.

Subject: Dangers of Abnormal Snow and Ice Build-up on Gas Distribution Systems.

Purpose: To inform owners and operators of the need (1) to monitor the potential impact of excessive snow and ice on these facilities; and (2) to inform the public about possible hazards from snow and ice accumulation on regulators and other pipeline facilities.

Advisory: PHMSA is advising operators of gas pipeline facilities, regardless of whether those facilities are regulated by PHMSA or state agencies, to consider the following steps to address the safety risks from accumulated snow and ice on pipeline facilities:

1. Notify customers and other entities of the need for caution associated with excessive accumulation and removal of snow and ice. Notice should include the need to clear snow and ice from exhaust and combustion air vents for gas appliances to prevent accumulation of carbon monoxide in buildings or operational problems for the combustion equipment.

2. Pay attention to snow and ice related situations that may cause operational problems for pressure control and other equipment.

3. Monitor the accumulation of moisture in equipment and snow or ice blocking regulator or relief valve vents which could prevent regulators and relief valves from functioning properly.

4. The piping on service regulator sets is susceptible to damage that could result in failure if caution is not exercised in cleaning snow from around the equipment. Where possible, use a broom, instead of a shovel to clear snow off regulators, meters, associated piping, propane tanks, tubing, gauges or other propane system appurtenances.

5. Remind the public to contact the gas company or designated emergency response officials if there is an odor of gas present or if gas appliances are not functioning properly. Also remind the public that, if there is a gas or propane odor, occupants should leave the residence immediately and contact their gas company, propane operator or designated emergency response officials.

Authority: 49 U.S.C. chapter 601; 49 CFR 1.53.

Issued in Washington, DC on March 5, 2008.

Jeffrey D. Wiese,

Associate Administrator for Pipeline Safety.