Gas fire suppression system for a server or plant room: agents, safety, the HFC phase-down and servicing

The one whose agent suits the room's people, leaks and future refills. A gas fire suppression system is a fixed installation that discharges an extinguishing gas into a closed room when it detects a fire.^[15][14]

In South Africa, the SANS 14520 series covers gaseous fire-extinguishing systems, one part per agent. Part 1, the general requirements, is SANS 14520-1:2026, edition 4, approved by the SABS on 30 March 2026.^[1]

The agents fall into three groups: halocarbons such as HFC-227ea and FK-5-1-12, inert gases such as IG-541, IG-55 and IG-100, and carbon dioxide. Each later part of SANS 14520 covers the physical properties and system design for its agent.^[1][2][3][4]

Portable equipment in the same room is a separate duty, covered by the fire extinguisher service page.^[14]

HFC-23 has the highest 100-year global warming potential below, at 14,800; the inert gases have the lowest, at zero. The Kigali Amendment gives the HFC figures, and the US EPA's SNAP list the others.^[5][12]

Sources:^{[5][12][1][2][3][4]}

It depends on the agent, and carbon dioxide is the dangerous one. The US Environmental Protection Agency reported in February 2000 that carbon dioxide is lethal at its minimum total-flooding design concentration of 34%.^[11]

The same EPA report states that above 17% carbon dioxide, unconsciousness, convulsions and death occur within one minute of breathing it. It found 51 incident records from 1975 to 2000, with 72 deaths and 145 injuries from carbon dioxide system discharges.^[11]

For the other agents, the EPA's SNAP list points to the NFPA 2001 safety guidelines. It also limits an IG-541 design concentration to no more than 5% carbon dioxide.^[12][1]

In South Africa, section 8 of the Occupational Health and Safety Act requires a workplace safe and without risk, as far as reasonably practicable. Section 8(2)(b) asks the employer to eliminate or mitigate a hazard before resorting to protective equipment. The same OHS Act sets duties towards the contractors who service the system.^[10]

Yes, gradually, under the Kigali Amendment, which South Africa ratified on 1 August 2019. The UN Ozone Secretariat records that South Africa reported its HFC licensing system on 19 April 2022.^[7]

Kigali lists HFC-227ea and HFC-23 among the controlled HFCs. South Africa is not one of the ten developing countries given the later schedule in decision XXVIII/2, so the earlier one applies.^[5][6]

That schedule caps HFC consumption from 2024 at a baseline built from the average 2020 to 2022 HFC consumption, plus 65% of the HCFC baseline. The cap falls to 90% in 2029, 70% in 2035, 50% in 2040 and 20% from 2045.^[5]

Halons are treated more strictly, as ozone-depleting substances. Regulation 3(1)(c) of South Africa's 2014 ozone regulations prohibits producing, importing, using or selling halons unless for a critical use.^[8]

Halons reclaimed from existing fire protection systems before the 2014 regulations took effect are exempt (regulation 3(2)). Using recovered halons in an existing system needs the Director-General's approval (regulation 3(3)). The 2021 amendment's list names Halon 1211, 1301 and 2402.^[8][9]

A room integrity test is a door fan test that predicts how long the agent will stay in the room after a discharge. In practice, ISO 14520 and other clean-agent standards recognise it as part of system acceptance.^[13]

A fan in a doorway blows air out of the room, then in, at a small test pressure. Software turns the flow and pressure readings into an equivalent leakage area and a predicted retention time.^[13]

The test maker's guidance is to repeat the test every year, and whenever new holes are made in the room's walls, floor or ceiling.^[13]

At least yearly, by a competent person. Johannesburg requires every service installation, including an automatic fire-extinguishing installation, to be inspected at least every 12 months by a registered, competent person (section 16(1)(c)(iii)).^[14]

Johannesburg also requires servicing to the manufacturer's specifications. After each service, the technician must certify in writing that the installation is fully functional (section 16(2)).^[14]

eThekwini's Fire By-law, 2022 lists gaseous, powder and foam systems at a 12-monthly interval, to SANS 14520 and the manufacturer's specifications. The technician must be registered with a body the Municipality recognises (section 31(1)).^[16][14]

Occupants must be told before a test of any alarm part of the system. Cape Town also requires notice to the parties who monitor the system (section 18(2)).^[15][16][14]