Basement Plant Room: Alarm and a Collapsed Cleaner

First five minutes

1. Do not go down the stairs. Treat the plant room and stairwell as an unsafe atmosphere until proved otherwise.
2. Call 999 or 112 and state that a person is unconscious in a basement plant room with a suspected refrigerant release. Fire service crews have breathing apparatus and gas detection; the technician has neither.
3. Raise the alarm in the shop, move customers and staff away from the stairwell, and post someone at the door to stop anyone wandering in.
4. Isolate power at a point outside the room if that can be done without entering, and without operating any switch inside the space.
5. Give the casualty what help is possible from fresh air - clear the landing if it can be done without entering the plume - and nothing more.

Why the manager is wrong R-134a vapour is roughly 3.5 times denser than air and will be lying in the plant room and spilling up the stair. Entering without breathing apparatus would very likely produce a second casualty at the bottom of the stairs, and then a third when someone tries to rescue the second. The valve can wait; the rescuer cannot be replaced. A single-handed entry into a confined space with a known release is exactly the scenario the emergency procedures exist to prevent.

The numbers

• Room volume: 4 x 3 x 2.4 = 28.8 m3, holding roughly 35 kg of air.
• R-134a vapour at room temperature is about 4.2 kg/m3, so 1 kg of liquid gives roughly 0.24 m3 of vapour.
• 20 kg of a 90 kg charge would give about 4.7 m3 of vapour, some 16% of the room. That displaces enough air to take oxygen from 21% down to roughly 17.6% - dizziness, headache, impaired judgement, poor coordination. A larger release, and 90 kg could fill most of the room, would be rapidly fatal.

Likely cause Oxygen deficiency, not poisoning. R-134a is a low-toxicity refrigerant; its danger in a basement is that it is heavier than air, has nowhere to go, and silently replaces the air. The cleaner's dizziness and semi-consciousness fit that pattern, and possibly a cold exposure as well.

Two traps

• The 'faint sweetish smell' is not a warning property and not something to rely on; HFCs give no reliable odour warning at dangerous concentrations.
• At high temperature or in contact with a flame or hot surface, R-134a decomposes to hydrogen fluoride and other irritant products, which is another reason not to operate anything electrical inside the room.

PPE

• Nothing in the technician's kit is suitable for entry. Nitrile gloves and safety glasses are fine for routine work on liquid lines, but they give no protection against an oxygen-deficient atmosphere.
• Entry and rescue require positive-pressure self-contained breathing apparatus, worn by trained people, working in pairs with a standby. That is the fire service's job here, not the technician's.
• After the area has been ventilated and tested with a calibrated oxygen meter and a refrigerant detector, the technician can work in the space with normal PPE plus gloves and goggles.

First aid for the casualty

• Move to fresh air only if it is safe to do so; otherwise wait for BA crews.
• If liquid refrigerant has contacted skin: flush with lukewarm water for at least 15 minutes, do not rub the area, do not pull off clothing that has frozen to the skin, cover with a sterile non-adherent dressing, and get medical attention - frostbite and cold burns need assessment.
• Eye contact: irrigate with clean water for at least 15 minutes and refer.
• If breathing but unresponsive, recovery position and oxygen if trained; if not breathing normally, CPR and AED.

Afterwards

• Report the incident, record it, and do not restart the plant until the leak is located, repaired, the room ventilated and the atmosphere tested. Review why a 90 kg R-134a machine in a sealed basement had no fixed detection.