gas liquefied under pressure, colourless, odourless, ethereal odour
Odour
odourless
1 ppm at 20 °C
7.07 mg/m³
Behaviour with temperature and pressure
Boiling point -17.3 °C at 1 atm: a liquefied gas under its own vapour pressure in cylinders. Critical point 100 °C / 29.5 bar: below this temperature it can be stored as a liquid; cylinder pressure then equals the vapour pressure. Vapour pressure ≈ 3.993 bar at 20 °C — this is the pressure inside a cylinder or a switchgear compartment at that temperature, and it rises steeply with temperature (Clausius–Clapeyron). Relative density 6.1244 (air = 1): heavier than air — accumulates in pits, cable basements and at floor level; place sensors low. Conversion at 20 °C, 1013 mbar: 1 ppm = 7.07 mg/m³; NDIR reads partial pressure, so readings scale with absolute pressure (value = reading × P/1013) and must be pressure-compensated.
// Non-combustible gas., Gas is heavier than air., Danger of suffocation at high concentrations due to oxygen displacement.
Hazards & safety
NFPA 704
health · flammability · instability · special
GHS / CLP pictograms
GHS04 · Gas under pressure
Hazard class
asphyxiant; greenhouse gas (F-gas Annex I)
GHS signal word
Warning
CLP classification
Gases under pressure, liquefied gas; H280
Hazard statements
H280: Contains gas under pressure; may explode if heated.
// Limits change: always confirm the current national value before setting an alarm. Values above were read from the EU directives / GESTIS / NIOSH pages listed in Sources.
Effect on people
Low toxicity (used as a fire-suppression agent at 7–9 vol%); cardiac sensitisation NOAEL ~9 %. Decomposes to HF in fire. Heavier than air (6×).
Recommended monitoring
NDIR (8–9 µm) for fire-suppression agent room monitoring (concentration proof after discharge, leak detection of cylinders).
