Electrical & process

Control Rooms & Substations

Clean agent suppression where water would destroy what it saves.

Discuss this hazard

At a glance

Hazard family: Electrical & process
Protected by: Clean agent, Fire alarm, CO₂, Water mist
Designed to: NFPA 2001, NFPA 12, NFPA 72, IS 2189
Clean agent discharge time (halocarbon): 10 seconds

Design basis

Clean agent discharge time (halocarbon): 10 secondsNFPA 2001
Clean agent hold time: At least 10 minutesNFPA 2001
Smoke detector spacing, smooth ceilings: 9.1 m nominalNFPA 72

Standards that apply

NFPA 2001Clean agent fire extinguishing systems.
NFPA 12Carbon dioxide extinguishing systems.
NFPA 72Fire alarm and signalling.
IS 2189Automatic fire detection and alarm systems.

The risk

Fires here start in electrical panels and cables and are usually small — but the consequence is out of all proportion. Losing a control room or a substation can shut down a plant that is otherwise undamaged.

Water is not an option on energised equipment, and control rooms are occupied around the clock.

The scheme

Detect the fire at the smouldering stage, and suppress without water:

Very early smoke detection — aspirating detection in critical rooms.
Clean agent total flooding for occupied rooms; CO₂ for unoccupied electrical rooms and cable cellars.
Interlocks that shut down ventilation and close dampers before discharge.