Gas utilities should repair plastic
gas mains
Timothy W. Pramik, A.S.P.
Safety and Health Administrator
UGI Utilities, Inc., Gas Division
Harrisburg, Pennsylvania
I wish to comment on “Plastic Gas Mains: Hazards and Tactics” (Fire Engineering, December 1995). The author of this article, in my opinion, has expanded the role of the fire department beyond its resources and expertise. This creates a more hazardous working environment for firefighters who already are pushed to their educational and physical limits.
Fire departments and natural gas utilities have worked closely together for many years in mitigating leaks in distribution mains, services, and fuel lines. Natural gas utilities have provided training to fire departments so guidelines may be established on the roles each is responsible for. It would be crazy to think that a gas company construction crew or service technician would enter a burning structure to extinguish a fire. Utility personnel`s primary duties in this case would be to assist the fire department with terminating natural gas services to the structure. Likewise, natural gas utilities do not expect fire departments to repair damaged facilities but to make the area safe until the proper personnel and equipment can arrive on the scene.
The author details several tactics for repairing leaks in plastic gas mains and services. This should be performed by the natural gas utility, as I stated above; but let me point out some areas that could result in additional damage to the facilities and expose firefighters unnecessarily:
1. If the plastic main or service is not exposed, firefighters should never try to excavate the area. Without exact locations, they will not know where the gas main or service is. Shovels can cause damage to one-inch or smaller plastic service lines and may create a path to ground source.
2. The author describes how to dissipate the static by pouring the soapy water on the line near the leak. This could create an electric path to ground through the firefighter. Also, the cloth wrap should be started at the ground end of the excavation. The application of soapy water is to safely dissipate the static to ground, not to have it discharged to ground.
3. The use of repair sleeves on plastic lines is not a common practice in the natural gas industry. This type of temporary repair of plastic pipe is not recommended, especially if the natural gas is still blowing.
4. Plugs are rarely used to stop the flow in plastic lines because it is another possible static electric ground when being installed. Remember, static electricity will take the easiest path to ground available.
5. Clamping or using squeeze-off tools should be done by utility personnel only. As the author states, it is next to impossible to know the gas flow direction without a good mapping system. Also, utility personnel will perform this from another excavation away from the leak, and the tool will be grounded. A clamp or squeeze-off tool, if not approved for plastic pipe, can damage the pipe.
6. Trying to kink a gas line larger than one inch is not recommended. Also, doing so would put the firefighters in danger if the static protection method should be broken.
Repairing leaks on natural gas mains, especially plastic mains, and services is a very technical field. The author leads one to believe that with some training, fire departments can safely perform these tasks. Fire department response to natural gas leaks should focus on life safety, not facility repairs.
Alternatives to the methods for handling outside leaks in plastic gas mains outlined in the December article are the following:
1. Notify the natural gas utility at dispatch. This allows the utility to dispatch the appropriate personnel on the information received. It also reduces the time the fire department will be on the scene without the assistance of the utility.
2. On arrival, the incident commander`s first priority is to determine if evacuation is necessary. For outside exposed leaks, a 200-foot minimum is recommended. Greater distances might be necessary if circumstances warrant. No one, including firefighters, should be permitted within the evacuation zone.
3. Shut off the gas if possible. This should be done at a remote valve, such as that for a meter set. Some utilities train fire departments to terminate natural gas at underground service (curb) valves.
4. Eliminate all possible ignition sources–any source that produces an ignition temperature higher than 900°F (vehicles, road flares, and electrical equipment, for example).
5. Ventilation is not necessary if the leak is exposed and outside. It is not necessary to use water fog or other mechanical means to move the natural gas away from exposures. Ventilation of confined spaces should be done only after all ignition sources have been eliminated. Natural ventilation techniques should be used.
The best recommendation I can give any fire department that elects to implement the tactics in this article is to contact your local utility and have each organization`s responsibilities defined. Determine if the local natural gas utility can provide the training for this type of operation, and also evaluate your resources to determine if your department can provide the service.
Remember, outside blowing gas leaks in plastic mains should be treated as hazardous-material incidents. The standard response cycle for these incidents is to isolate, evacuate, and deny entry, which provides safety for firefighters and the citizens we protect.
