EP Natural Gas Emergencies & Fires

PURPOSE

The guide aims to enhance operational efficiency and awareness during natural gas emergencies by detailing infrastructure and risk assessment.

BACKGROUND

As reliance on natural gas increases in NYC, the aging infrastructure raises risks of leaks and fires. Gas leak responses have doubled in recent years, necessitating effective mitigation measures.

PROPERTIES OF NATURAL GAS

• Mainly methane; highly flammable with an explosive range of 5% - 15%.
• Colorless and odorless; mercaptan is added for detection but can be masked.
• Lighter than air and non-toxic, yet can cause asphyxiation in confined spaces.

GAS SYSTEM INFRASTRUCTURE

• Con Edison and National Grid manage NYC's gas distribution.
• Gate stations, transmission mains, and distribution mains are critical components, with pressure reduction occurring at regulator stations.

STRATEGY & TACTICS

• Most emergencies are mitigated through direct actions; however, escalations can occur, requiring life safety as a priority.

RESPONSE POLICY

Conditions indicating a major emergency include:

• Serious infrastructure damage or high readings indicating potential risks.
• Metrics like 10% or greater LEL present.

MAJOR GAS EMERGENCIES

• Defined by significant risks that necessitate enhanced resources for mitigation and safety. Key indicators include serious infrastructure damage, high gas readings, and gas leaks in buildings.

INVESTIGATION

Initial steps involve assessing the emergency type, interviewing witnesses, and utilizing gas detection tools.

MITIGATION

Strategies include:

• Ventilation of affected areas.
• Elimination of ignition sources.
• Isolating leaks by controlling valves efficiently and safely.

INCIDENT COMMAND

Appoint a clear command structure during emergencies to coordinate response efforts, ensuring evaluation and evacuation practices are adhered to.