PIPELINE SAFETY ADVISORY BULLETIN
Advisory Bulletin: ADB-97-01 Date: 01/24/97

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

Subject: Potential Damage to Pipelines by Impact of Snowfall, and Actions Taken by Homeowners and Others to Protect Gas Systems from Abnormal Snow Build-up

Purpose:

Inform System Owners and Operators of the Need to Inform the Public of Possible Hazards Relating to Snow Accumulation on Pipeline Facilities, and to Monitor the Potential Impact of Snow Accumulation on Those Facilities

Advisory:

During January 1 through January 17, 1997, a series of heavy snowfalls and sub-zero temperatures in the northern states in the Midwest have increased the potential for damage to pipeline facilities. Several accidents have occurred on narura1 gas distribution system facilities that appear to be related to either the stress of snow and ice on the facilities or frost heave. Damage can result to exposed piping, such as at metering and pressure regulating stations, at service regulators, and at propane tanks. This damage may result from the stresses imposed by the additional loading of the snow or ice. Damage to facilities may also be caused by the impact of snow or ice falling from roofs, as well as from actions taken to protect dwellings from abnormal snow accumulation by shoveling snow from roofs. Accordingly, the Research and Special Programs Administration (RSPA) is advising operators of gas pipeline facilities, regardless of whether those facilities are regulated by RSPA, to notify customers and other entities of the need for caution associated with excessive accumulation and removal of snow. Additionally, operators must be alert to snow- and ice-related situations that may cause operational problems for pressure control and other equipment.

Background:

RSPA reminds operators and owners of gas facilities, including propane systems, that precautions should be taken to address problems that may result from accumulation of snow or ice on exposed pipeline facilities, especially pressure control equipment and control lines. Accumulation of moisture in equipment and snow or ice blocking regulator or relief valve vents, could prevent regulators and relief valves from functioning properly.

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 setting. Where possible, a broom, instead of a shovel is more appropriate when clearing snow off regulators, meters, associated piping, propane tanks, tubing, gauges, or other propane system appurtenances. Heavy snow and ice falling from roofs can damage gas facilities, and special care must be taken when clearing roofs of snow and ice to prevent impact on regulators, meters, propane tanks, and associated piping. Exhaust and combustion air vents for gas appliances must be clear of snow and ice to prevent accumulation of carbon monoxide in buildings or operational problems for the combustion equipment.

As always, people should be reminded to contact the gas company or designated emergency response group if the odor of gas is detected or if gas appliances are not functioning properly. Additionally, if gas or propane odors are detected, consumers should leave the residence immediately and contact their gas company, propane operator, or designated emergency response group.

Issued in Kansas City, MO on January 24, 1997.

Ivan A. Huntoon, Director

Central Region, Office or Pipeline Safety

Research and Special Programs Administration