Which gas to choose for fire suppression: fluoroketone, HFC-227ea or HFC-125
If people are present in the room, fluoroketone FK-5-1-12 or HFC-227ea is chosen: their extinguishing concentration is below the human safety threshold. HFC-125 is kept for technical rooms that people leave before release. The final choice is made by calculation: it determines the fill mass, the number of modules and the system price.
How fluoroketone, HFC-227ea and HFC-125 differ
| Parameter | FK-5-1-12 | HFC-227ea | HFC-125 |
|---|---|---|---|
| Design concentration | 5,4 % | 7,2 % | 9,8 % |
| Safety threshold for people | 10 % | 9,0 % | 7,5 % |
| Safety margin | about 1.85 times | about 1.25 times | no margin |
| Module filling density | up to 1.2 kg/L | up to 1.1 kg/L | up to 0.9 kg/L |
| Atmospheric lifetime | 3–5 days | 34–37 years | 28–33 years |
| Global warming potential, GWP | less than 1 | 2 900–3 500 | 3 170–3 500 |
| Included in SP RK 2.02-102-2022 | no, designed under SN RK clause 9.1.6 | yes | yes |
| At FireStop | in stock | in stock | to order |
Halocarbon concentrations are taken from SP RK 2.02-102-2022, and the fluoroketone value from Russian SP 485 as amended by Amendment No. 2: it is not in the Kazakhstan code. The safety threshold follows NFPA 2001 (NOAEL), the concentration at which no adverse effect on people is observed.
How much agent and how many modules a 50 m³ room needs
Take a 50 m³ server room in Almaty and calculate it by the same method as the tables on our solution pages, with a 0.90 altitude correction. The mass grows with volume, so here it is half of what a 100 m³ room needs.
| Gas | Gas weight | How to cover it |
|---|---|---|
| HFC-227ea | 31.9 kg | one 30 l ceiling-mounted module, which holds up to 33 kg |
| Fluoroketone FK-5-1-12 | 43.9 kg | one 40 l floor-standing module or two 20 l ceiling-mounted modules |
| HFC-125 | 32.0 kg | one 40 l floor-standing module: a 30 l ceiling-mounted module holds only 27 kg |
This shows why the price per kilogram says little about the system price. HFC-227ea and HFC-125 need almost the same mass, but 227ea fills the cylinder more densely and fits into one ceiling-mounted module without pipes. Fluoroketone needs the largest mass, but it has the widest safety margin for people.
The figures are preliminary: the exact mass is calculated in the design from the tightness and openings of the room. You can estimate the mass for your room with the agent calculator.
Start with the room, not the agent name
Selection needs room dimensions, purpose, fire load, temperature range, occupancy and evacuation routes. Raised floors, ceiling voids, openings and ventilation are considered separately.
Room volume alone does not determine charge mass. Calculations consider agent use conditions and protected zone parameters. Input data and methods are addressed in Section 5.4 and Appendices G and D of SP RK 2.02-102-2022 (PDF).
What to clarify for each agent
| Agent | Designation | What to request from the supplier |
|---|---|---|
| Fluoroketone | FK-5-1-12 | Exact grade, safety data sheet, compatibility with the selected module and refill terms |
| HFC-227ea | HFC-227ea | Charge calculation, storage and discharge parameters, and agent and equipment documents |
| HFC-125 | HFC-125 | Suitability justification, concentration calculation, safety measures and servicing terms |
An agent name does not replace the specific batch datasheet or system documentation. Different manufacturers' brands cannot be treated as interchangeable without checking specifications and compatibility.
How to account for occupancy
Check design concentration and exposure conditions rather than general safe gas advertising claims. Suitability is assessed against regulations and agent documentation, considering room purpose and evacuation.
All systems require advance warnings, evacuation procedures and necessary interlocks. Gas suppression does not remove the need to evacuate. Re-entry after discharge requires responsible specialists' permission.
Fire effects are considered separately: smoke and thermal decomposition products may be hazardous regardless of agent brand. Read more in After gas discharge: restoring operations.
What Kazakhstan standards say
Table 8 of SP RK 2.02-102-2022 lists the agents for which the code provides a calculation method. They include HFC-227ea and HFC-125, as well as CO₂, nitrogen, argon and Inergen. FK-5-1-12 is not there, so under clause 9.1.6 of SN RK 2.02-02-2023 a system using it is designed to the documentation of the agent or system manufacturer.
Gas must not be used on materials that smoulder inside their volume, metal powders, hydrides or substances that burn without air: this is an explicit ban under clause 9.1.22 of SN RK 2.02-02-2023, and no choice of agent gets around it. For government server rooms, the Unified ICT Requirements (clause 160 of Government Decree No. 832) allow only automatic gaseous fire suppression.
All requirements with clause numbers are collected in the article Gaseous fire suppression standards in Kazakhstan.
What makes up the cost
Equipment
Modules, valves, pipework and controls
Readiness
Main charge, stock and specified reserve
Operation
Servicing, delivery and refilling
A cheaper agent does not guarantee a cheaper system: cylinder quantity and capacity are calculated. The offer should clearly identify equipment, installation work, documents and future servicing.
Clarify refill availability, logistics, deadlines and contract terms. Consider stock and reserve requirements before purchase, not after the first discharge.
What to send the engineer for selection
- Room plan with dimensions and height
- Facility purpose and protected equipment
- Raised-floor, ceiling-void and opening details
- Temperature range and ventilation scheme
- Occupancy and evacuation route information
- Delivery, servicing and protection restoration timing requirements
The result should be a justified design with mass, hydraulic and safety calculations. Equipment documents are available under Documentation, with examples at different facilities under Projects.
Frequently asked questions
Which gas is safest for people?
Fluoroketone FK-5-1-12: at an extinguishing concentration of 5.4% its safety threshold is 10%, almost twice as high. HFC-227ea has a margin of about 1.25 times. HFC-125 extinguishes above its own threshold, so people must leave before release. With any agent the system first triggers the warning and holds a delay for evacuation.
Why is HFC-125 chosen for electrical and cable rooms?
It is cheaper and suits rooms that people rarely enter and are certain to leave before the gas is released: cable spaces, transformer rooms, unattended electrical rooms.
Which gas is more environmentally friendly?
Fluoroketone: it breaks down in the atmosphere within 3–5 days, and its global warming potential is below 1. HFC-227ea and HFC-125 remain in the atmosphere for about 30 years, with a warming potential of about 3,000. None of the three gases depletes the ozone layer.
Can a FireStop module be filled with any of these gases?
Yes, FireStop modules are filled with HFC-227ea, HFC-125 and FK-5-1-12. The agent and fill mass are stated in the order based on the calculation. Switching an installed system to another agent is possible only after the design is recalculated.