Specialist Suppression Systems

Specialist suppression systems protect spaces and hazards where ordinary sprinklers are unsuitable or insufficient: data and communications rooms, switchrooms, archives, museums, heritage buildings, commercial kitchens, flammable liquid stores, aircraft hangars and industrial processes. They use gas, water mist, foam, wet chemical or water released only after detection confirms a fire.

Gaseous systems only work if the protected room holds the gas for the required time. Every cable, pipe and door added to the room after commissioning can let the gas escape, so room integrity is as important as the cylinders.

What shortens life:

• Room integrity lost by later penetrations and doors.
• Agent regulation: halon, HFC and PFAS controls end the useful life of systems that are mechanically sound.
• Panel obsolescence.
• Grease on kitchen system nozzles and links.

Loss of room integrity

Gaseous systems are designed to hold an extinguishing concentration for a set time. New cable penetrations, raised floor and ceiling changes, gaps under doors, and new ductwork let the gas leak away, so the fire reignites when the concentration falls. A door fan integrity test shows whether the room still holds.

Agent obsolescence and regulation

Halon production ended in developed countries in 1994; remaining systems must be decommissioned or justified. HFC-227ea is being phased down with other HFCs. A major producer of FK-5-1-12 stopped making PFAS products, changing supply. Older firefighting foams contain PFAS and are being banned or restricted in Australia, Britain, the European Union and many US states, with clean-up obligations.

Occupant safety

Carbon dioxide systems kill people who are in the room when they discharge; pre-discharge alarms, time delays, lock-off valves and signage must work. Inert gas systems lower oxygen to levels that are safe only for short exposures at design concentration.

Detection and control faults

Systems release only when detection confirms a fire, usually from two detectors. Faulty detectors, disabled panels, and abort or manual release switches left in the wrong position stop discharge or cause accidental discharge.

Pre-action faults

Pre-action pipework that holds water from tests corrodes; supervisory air leaks; valves fail to trip.

Kitchen system faults

Nozzles blocked with grease, fusible links not replaced, appliances moved from under nozzles, and gas shutoff interlocks bypassed.

Change of use

A room fitted out for one use and later used for another (more equipment, storage, people) can outgrow its design.

On site

• Cylinder labels: agent, fill date, test date; pressure gauges.
• Panel faults; isolations; manual or lock-off positions.
• New penetrations and gaps in protected rooms; doors without seals or closers.
• Warning signs and alarms at protected rooms.
• Kitchen nozzles greasy or out of position.
• Foam concentrate type and labels.

In the records

• Design and agent quantity calculations.
• Room integrity test reports.
• Service and cylinder test records.
• Halon or foam registers and decommissioning records.

• Room doors fitted without closers or seals after works.
• Raised floors and ceilings opened for cabling.
• Abort and manual release switches without labels or covers.

A protected room that fails its integrity test after recent works points to the works; one that fails without recent works points to ageing seals, doors and dampers.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

A fire services engineer leads, with a suppression specialist for the system type and, for kitchens, the hood and suppression contractor.

• Design review: hazard, agent, design concentration and hold time, room volume, and whether the room's use, contents and occupancy have changed.
• Room integrity test by door fan for gaseous systems, predicting hold time against the design, with leaks located by smoke pencil or thermal imaging.
• Cylinder and agent inspection: weight or pressure against the label, hydrostatic test dates, valves, discharge pipework and nozzles, mounting.
• Detection and control test: detectors, two-stage confirmation logic, pre-discharge alarms, time delays, abort and manual release, lock-off valves, interfaces to air handling shutdown and dampers.
• Occupant safety review for carbon dioxide and inert gas systems: signage, alarms, lock-off procedures, room access controls.
• Regulatory review of the agent: halon status, HFC phase-down, foam PFAS content and any decommissioning or clean-up obligations.
• Pre-action checks: supervisory air, low-point drains, internal condition, trip test.
• Kitchen system inspection: nozzle positions against current appliances, grease, fusible links, gas and power shutdown interlocks, manual release.

The report should state whether the system will suppress a fire in the room as it now is, the safety position, the agent's regulatory status, and works or replacement needed.

• Restore room integrity: seal every penetration with tested products, fit door seals and closers, seal raised floors and ceilings, then retest.
• Recalculate and recharge where room volume or use has changed.
• Replace regulated agents: decommission halon through approved channels; plan replacement of HFC-227ea systems; move to inert gas or other permitted agents, which may need more cylinder space and pressure relief venting.
• Replace PFAS foam with fluorine-free foam, with full system cleaning and disposal of old concentrate and rinse water under environmental rules.
• Panel and detection replacement with supported equipment.
• Safety measures for carbon dioxide: lock-off valves, alarms, signage, procedures, or replacement with a safer agent.
• Pre-action corrosion control: nitrogen supervisory gas, drainage, pipe replacement.
• Kitchen systems: reposition nozzles to match appliances, replace links, restore interlocks, clean regularly.

Servicing, room integrity testing and cylinder testing recur. Room sealing is a lump sum per room. Agent replacement is a lump-sum project per protected space, including new cylinders, pipework, nozzles, pressure relief and commissioning. Halon decommissioning and PFAS foam replacement carry disposal and clean-up costs that can be significant. Kitchen system servicing recurs, with replacement per hood.

Servicing, integrity and safety rectification are code compliance; agent replacement driven by regulation is a deadline item; system replacement at end of life is lifecycle.

• Australia. AS 4214 and ISO 14520 cover gaseous systems; AS 1851 sets routine service including room integrity checks; halon is controlled under the ozone protection legislation with use only under permit; several states and the Commonwealth restrict PFAS firefighting foams; kitchen suppression follows the relevant Australian Standard and AS 1851.
• United Kingdom. BS EN 15004 and BS ISO 14520 cover gaseous systems; halon use is restricted to listed critical uses; HFC agents fall under fluorinated gas regulations; PFAS foam restrictions apply under UK and EU chemical rules; kitchen systems follow LPS 1223.
• United States. NFPA 2001 covers clean agent systems, including annual enclosure integrity checks; NFPA 12 carbon dioxide with strict personnel safety requirements; NFPA 17A wet chemical systems; NFPA 11 foam; EPA and state rules restrict PFAS foams; NFPA 13 and 25 cover pre-action systems.

• Design and agent quantity calculations.
• Room integrity test reports with hold times.
• Service, cylinder weight and hydrostatic test records.
• Detection and control test records.
• Halon register and decommissioning records; foam product data and PFAS status.
• Carbon dioxide safety procedures and lock-off records.
• Kitchen system service records and link replacement dates.
• Records of works in protected rooms.