Most systems rely on a flexible detection tube routed through the cabinet. The tube bursts at the hottest point and the agent is released into that space, with no electrical supply required. We inspect the enclosure volume, ventilation openings and cable density on site and choose the agent and tube route accordingly.
ATypes and components
Direct system
The detection tube is also the discharge line. When heat bursts the tube, the agent comes straight out of the opening onto the seat of the fire; a simple, economical option for small and medium enclosures.
Indirect system
When the detection tube bursts, the pressure drop opens a valve and agent is delivered through separate pipework and nozzles. Preferred for larger cabinets or where several compartments need even distribution.
FK-5-1-12 and HFC-227ea systems
Non-conductive, residue-free halocarbon agents that do not harm circuit boards or contacts. These are the most common agents for in-panel use.
CO₂ systems
Suitable for enclosed machine housings and small spaces with no human access. Where the gas could escape from the enclosure, the hazard CO₂ poses to people must be taken into account.
Condensed aerosol units
Compact generators that, when triggered, burn a solid compound to produce very fine potassium salt particles that interrupt the flame chain reaction. There is no pressure vessel, but they can leave a fine powder residue, which matters around sensitive electronics.
Pressure monitoring and signal contact
Tube pressure is monitored by a gauge and pressure switch. A discharge or loss-of-pressure signal goes to the fire alarm panel or BMS, and can be wired to trip the panel supply if required.
BHow it works
- Temperature inside the cabinet rises and the detection tube softens and bursts at the hottest point.
- Tube pressure drops; in a direct system agent discharges from the burst point, in an indirect system through the nozzles.
- The agent fills the enclosure and extinguishes the fire at its earliest stage.
- The pressure switch signals an alarm and, where specified, power to the panel is isolated.
CAdvantages
- Detects and extinguishes at the source, inside the cabinet
- No electrical supply needed
- Clean agents keep equipment damage to a minimum
- Easy to retrofit to existing panels
- Far lower cost than room-scale gas protection
DApplications
- Distribution and power factor correction panels
- Motor control centres (MCC)
- Server and network racks
- UPS and battery cabinets
- CNC machines and machine enclosures
- Wind turbine nacelle panels
- Laboratory fume cupboards
EFrequently asked questions
Does the panel have to be fully sealed?
It does not need to be airtight, but openings must be limited so the agent stays in the cabinet long enough to extinguish the fire. For large ventilation grilles or fan-cooled cabinets, the agent quantity is increased or the fans are stopped on discharge. We assess this for each panel during the site survey.
Should power to the panel be cut when the system discharges?
In most cases, yes. While the faulty component stays energised it keeps heating, and the fire can restart once the agent disperses. For critical loads, an alarm followed by a controlled manual shutdown may be preferred over an automatic trip; that decision should be made with the operator.
How long does a detection tube last?
Tubes age with exposure to heat, UV light and chemicals, so manufacturers recommend replacement after a set service life. Routine maintenance checks tube pressure, routing and fixings. It also matters that later work on the panel does not crush the tube or leave it rubbing against sharp edges.