HFC-227ea (FM-200) — chemical name Heptafluoropropane — is a clean agent fire suppressant: colourless, odourless, non-conductive, and leaves no residue after discharge. Unlike water or dry powder suppression, which can cause catastrophic damage to electronic equipment, FM-200 extinguishes fires through rapid heat absorption without affecting machinery or assets — making it the system of choice for thousands of organisations protecting server rooms, switchrooms, archives and irreplaceable assets.
1. What is HFC-227ea (FM-200) and why is it needed?
In many modern facilities — particularly data centres, control rooms, dry-type transformer rooms, document archives and museums — the discharge of water to suppress a fire can cause damage far greater than the fire itself. A flooded server room can mean total data loss; a medium-voltage switchroom exposed to water can trigger a more serious incident than the original fire.
HFC-227ea (FM-200) solves this problem. The system operates on the total flooding principle: when sensors detect a fire, agent is discharged rapidly, distributing uniformly throughout the protected space, reaching design concentration within 10 seconds, and extinguishing the fire before it can spread.
2. Typical applications of HFC-227ea (FM-200)
| Facility type | Reason HFC-227ea (FM-200) is preferred |
|---|---|
| Server rooms, Data Centres | No wetting of equipment; no data interruption; extinguishes before hardware damage occurs |
| Transformer rooms, medium-voltage switchrooms | Non-conductive; no secondary short-circuit on discharge into live equipment |
| Control rooms, PLC/SCADA cabinets | Protects plant control systems and continuous production lines |
| Telecommunications rooms, central exchanges | Maintains telecom infrastructure without service interruption |
| Document archives, museums | Protects legal records, artworks and irreplaceable artefacts |
| Generator rooms, UPS and battery rooms | Controls electrical fires rapidly; prevents cascading failure in power systems |
3. Agent quantity calculation — TCVN 7161-9:2024
Under TCVN 7161-9:2024 (equivalent to ISO 14520-9:2019), the required HFC-227ea charge for each protected space is calculated individually, based on room volume, fire hazard class and ambient temperature. The core formula is:
- Q — required HFC-227ea charge (kg)
- c — design concentration (% v/v); typically 8.5% for server rooms
- V — net protected volume (m³), excluding fixed non-permeable objects
- v — specific volume of HFC-227ea vapour (m³/kg) = 0.1269 + 0.000513 × T (where T = room temperature °C)
Design concentration by fire hazard class
| Hazard class | Minimum design concentration | Notes |
|---|---|---|
| Class B — Heptane (flammable liquids) | 9.0% | Safety factor 1.3 × extinguishing concentration |
| Class A surface — Plastics, wood, paper | 7.9% | Safety factor 1.3 × extinguishing concentration |
| Class A high-hazard — Cables, electronic equipment | 8.5% | Server rooms, switchrooms, PLCs |
Source: Table 4, TCVN 7161-9:2024 (ISO 14520-9:2019)
Problem: Server room 6 × 5 × 3 m, temperature 20°C, containing 5 equipment racks (total volume 2.5 m³), design concentration 8.5%.
Step 1 — Net volume: V = 6 × 5 × 3 = 90.0 m³
Step 2 — Specific vapour volume at 20°C: v = 0.1269 + 0.000513 × 20 = 0.1372 m³/kg
Step 3 — Required charge: Q = (8.5 / 91.5) × (90.0 / 0.1372) ≈ 61.0 kg
Result: One cylinder of 82.5 litres / 42 bar, filled at ~740 kg/m³ (≤ 1,150 kg/m³ per TCVN 7161-9:2024)
4. Key technical requirements
- Discharge time: The system must reach 95% of design concentration within 10 seconds (TCVN 7161-1:2022, Art. 7.9.1.1)
- Hold time: Design concentration must be maintained for a minimum of 10 minutes after discharge to ensure complete extinguishment
- Room integrity: All penetrations, floor/wall openings and HVAC openings must be sealed to prevent agent loss before the hold time has elapsed
- Automatic HVAC shutdown: All AHU and exhaust fans must shut down automatically on system activation (TCVN 7161-1:2022, Art. 7.4.3)
- Pre-discharge warning: Flashing lights and alarm sounders must operate throughout the delay period to allow occupant evacuation
- Occupant safety: NOAEL = 9.0% — the standard design concentration is within the safe limit for human exposure (TCVN 7161-9:2024, Table 7)
Frequently Asked Questions
Is HFC-227ea (FM-200) safe for people when the system discharges?
At the standard design concentration (≤ 9.0% v/v), HFC-227ea causes no observable adverse effects — this is the NOAEL (No Observable Adverse Effect Level) recognised by TCVN 7161-9:2024. However, the system must include audible and visual alarms and a time delay (typically 30–60 seconds) before discharge, to allow occupants to evacuate before agent is released.
Why must the room be airtight when using HFC-227ea (FM-200)?
HFC-227ea must maintain its design concentration throughout the entire hold period (≥ 10 minutes) to fully extinguish the fire. If the room has significant leakage — under doors, through cable penetrations, or through unsealed HVAC openings — agent will escape and concentration will fall below the extinguishing level before the fire is fully controlled. A door fan test (enclosure integrity test) after installation is mandatory.
How is HFC-227ea (FM-200) different from CO₂ suppression?
CO₂ suppresses fires by reducing the oxygen concentration to a level that cannot sustain combustion — at design concentration (35–40%), CO₂ is immediately life-threatening. HFC-227ea suppresses by heat absorption; at design concentration (≤ 9%) it is safe for brief human exposure. HFC-227ea is therefore used in occupied spaces or spaces with regular human access; CO₂ systems require strict interlocks against accidental discharge and appropriate safety measures if used where people may be present.
What periodic maintenance does an HFC-227ea system require?
Under TCVN 7161-1:2022, HFC-227ea systems must be inspected every 6 months: cylinder weight verification (against the charged weight), pressure check, alarm and interlock functional test. If the agent mass has decreased by more than 5% from the design charge, the cylinder must be recharged.
Need HFC-227ea (FM-200) system design and consulting?
VIETSAFE E&C engineers provide FM-200 system design, agent quantity calculations, and complete fire safety dossier preparation for submission to the fire authority.
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