FM-200 (HFC-227ea) and Novec 1230 (FK-5-1-12) are both clean agents, and both are designed with the same NFPA 2001 formula. The main differences are concentration, safety margin and environment. For a Class C hazard, FM-200 needs a 7.0% design concentration and has a 9.0% NOAEL. Novec 1230 needs 4.5% and has a 10% NOAEL. Novec 1230 also has a GWP of about 1, but it needs more agent by mass for the same room.
So which one is better? Neither agent wins on every point. The right choice depends on the room, the people inside it, the space for cylinders and local environmental rules. This guide compares fm200 vs novec 1230 using NFPA values only, with one worked example. You can run your own room in the free clean agent calculator.
How Both Agents Work
Many site teams think clean agents remove oxygen like CO2. They do not. HFC-227ea and FK-5-1-12 put out fire mainly by absorbing heat. Oxygen in the room stays at a level people can breathe at normal design concentrations.
Both agents use the NFPA 2001 (2018) quantity formula: W = (V/s) × C/(100 − C). V is the net volume, s is the specific vapour volume at the minimum design temperature and C is the design concentration. Only the value of s changes:
- HFC-227ea (FM-200): s ≈ 0.1269 + 0.0005·t (m³/kg, t in °C)
- FK-5-1-12 (Novec 1230): s = 0.0664 + 0.0002741·t
Novec 1230 has a much smaller specific volume. Each kg makes less vapour, so you need more kg, even at a lower percentage.
Side-by-Side Comparison
| Property | FM-200 (HFC-227ea) | Novec 1230 (FK-5-1-12) |
|---|---|---|
| Class A MEC | 5.2% | 3.3% |
| Class A minimum design | 6.7% | 4.5% |
| Class B (heptane) design | 8.7% | 5.85% |
| Class C minimum design | 7.0% | 4.5% |
| NOAEL | 9.0% | 10% |
| LOAEL | 10.5% | >10% |
| Storage | Liquefied gas, max fill density 1,153 to 1,265 kg/m³ | Stored as liquid, max fill density up to 1,442 kg/m³ |
| Environment | Hydrofluorocarbon, high global warming potential | ODP 0, atmospheric lifetime about 5 days, GWP about 1 |
| Agent for a 240 m³ Class C room at 20 °C | 131.6 kg | 157.3 kg |
Same Room, Two Agents
Take a 10 × 8 × 3 m server room. Net volume is 240 m³. The hazard is Class C and the minimum design temperature is 20 °C.
- FM-200 at 7.0%: W/V = 0.5482 kg/m³, so W = 131.6 kg. Peak concentration at 30 °C is about 7.25%.
- Novec 1230 at 4.5%: W is about 157.3 kg.
Novec 1230 needs more mass. But it is stored as a liquid at a higher fill density, so the cylinder volume difference is smaller than the mass difference suggests. Compare the full listed cylinder layout, not only the kg.
If you want to see how the FM-200 number is built, watch the TPFE video How to Calculate FM200 System Gas Quantity. The same steps apply to Novec 1230 with its own specific volume.
Safety Margins in Occupied Spaces
This is where the two agents really differ. The gap between design concentration and NOAEL is your safety margin for people.
- FM-200: Class C design 7.0%, NOAEL 9.0%, LOAEL 10.5%.
- Novec 1230: Class C design 4.5%, NOAEL 10%, LOAEL above 10%.
NFPA 2001 rules for normally occupied spaces are the same for both agents:
- Designs up to NOAEL are permitted, with a maximum exposure of 5 minutes.
- Above NOAEL, only with means to limit exposure according to the exposure tables.
- Above LOAEL, not permitted in normally occupied spaces.
- In unoccupied spaces above LOAEL, people must be able to leave within 30 seconds, with a pre-discharge alarm and time delay.
For FM-200, the exposure table 1.5.1.2.1(c) is strict. Up to 10.5% allows 5 minutes, 11.0% allows 1.13 minutes, 11.5% allows 0.60 minutes and 12.0% allows 0.49 minutes.
A common spreadsheet mistake hits FM-200 hard. Multiplying the 7.0% Class C design value by 1.35 again gives 9.45%, above the 9.0% NOAEL. Doing the same with the 8.7% Class B value gives 11.31%, above the 10.5% LOAEL. Apply safety factors to the MEC only, for both agents.
Storage, Discharge and Environment
Both agents must discharge within 10 seconds to reach 95% of the minimum design concentration. Both must hold at least 85% of the adjusted minimum design concentration at the highest protected content for 10 minutes, or until trained personnel respond. Both need a room that passes an enclosure integrity (door fan) test.
On the environment, FK-5-1-12 has an ozone depletion potential of 0, an atmospheric lifetime of about 5 days and a GWP of about 1. HFC-227ea does not harm the ozone layer, but as a hydrofluorocarbon it has a high global warming potential. Many countries now control HFCs under phase-down rules. Check your local regulations and your client's sustainability policy before you specify.
How to Choose Between FM-200 and Novec 1230
- Normally occupied rooms: Novec 1230 gives a wider margin between design concentration and NOAEL.
- High Class B concentrations: FM-200 at 8.7% is close to its NOAEL. Check the peak concentration at maximum temperature with care.
- Environmental targets: Novec 1230 has a GWP of about 1. HFC rules may limit FM-200 on some projects.
- Cylinder space: compare the full listed cylinder layouts, not only the agent mass.
- Existing systems: do not change agents in an existing system without a full redesign. Pipe sizes, nozzles and flow calculations are agent-specific.
FM-200 vs Novec 1230 FAQ
Is Novec 1230 safer than FM-200?
Why does Novec 1230 need more kg than FM-200?
Do FM-200 and Novec 1230 remove oxygen from the room?
Can I replace FM-200 with Novec 1230 in an existing system?
What is the environmental impact of Novec 1230?
Sources: NFPA 2001, Standard on Clean Agent Fire Extinguishing Systems and NFPA 12, Standard on Carbon Dioxide Extinguishing Systems. Values are from NFPA 2001 (2018 edition) and NFPA 12. Always check the edition adopted by your Authority Having Jurisdiction and the listed manufacturer's design manual.
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