Equipment

A gas rescue team carries equipment for three things: breathing, measuring and working. The first two are what set the profession apart.

Respiratory protection

Filtering devices are not enough

A filter mask cleans the air the wearer breathes, but it cannot add oxygen and it only works against substances its filter is designed for, in limited concentrations. In an unknown atmosphere, in confined spaces or where oxygen may be low, rescuers use isolating breathing apparatus that does not depend on the surrounding air at all.

Open-circuit compressed air apparatus (SCBA)

The most common type. Compressed air is carried in a cylinder on the back, typically at 300 bar. A pressure reducer and a lung-demand valve deliver air to a full-face mask; exhaled air goes out through an exhalation valve. Modern sets work with positive pressure: the pressure inside the mask stays slightly above ambient, so a small leak lets air out rather than letting gas in.

Working duration depends on cylinder volume and on how hard the wearer works — roughly half an hour to an hour for common sets. The wearer watches a pressure gauge, and a warning whistle sounds when the reserve is reached.

Closed-circuit apparatus (rebreathers)

For long operations, such as deep mine rescue or long tunnels, closed-circuit apparatus is used. Exhaled breath is passed through a carbon-dioxide absorbent and topped up with oxygen from a small cylinder, so the same gas is breathed again. Rebreathers give two to four hours of protection at a much lower weight than the equivalent compressed air, but they require more training and careful maintenance.

Escape sets and rescue masks

Short-duration escape hoods and self-rescuers are carried for casualties and for the rescuers' own emergencies. A rescuer who finds a conscious casualty first gives them breathing protection, then evacuates them.

Inspection and testing

Every set is checked before use (high pressure, leak tightness, warning signal, mask seal) and undergoes regular workshop tests. Records are kept for each apparatus and each cylinder.

Gas detection

Why instruments

Many dangerous gases have no smell or colour, and some, such as hydrogen sulfide, paralyse the sense of smell at high concentration. Decisions are made on measurements, never on the senses.

Typical sensors

• Oxygen — electrochemical sensor. Normal air contains about 20.9 % oxygen by volume. Both deficiency and enrichment are dangerous.
• Flammable gases — catalytic or infrared sensors reading in percent of the lower explosive limit (LEL).
• Toxic gases — electrochemical sensors for carbon monoxide, hydrogen sulfide, chlorine, ammonia, sulfur dioxide and others, reading in parts per million.
• Volatile organic compounds — photoionisation detectors (PID) for solvents and fuel vapours.
• Carbon dioxide and methane — infrared sensors.

Portable and fixed detectors

Rescuers carry personal multi-gas detectors (typically O₂, LEL, CO and H₂S) that alarm immediately. Separate instruments with sampling pumps and probes are used to measure inside tanks, wells and pipes before anyone enters. Fixed detectors at facilities give early warning and start ventilation or shut-down automatically.

Bump tests and calibration

A detector is only as good as its last check. Before each shift, a bump test with a known gas confirms that the sensors and alarms respond. Full calibration is done at regular intervals and after any doubtful reading.

Other equipment

• Communication: intrinsically safe radios, often with mask-mounted microphones.
• Ventilation: portable fans and ducts, including explosion-proof versions.
• Leak sealing: clamps, plugs, inflatable cushions, tools that do not produce sparks.
• Rescue: stretchers suitable for narrow spaces, tripods and winches, rope systems.
• Protective clothing: from flame-resistant suits to gas-tight chemical suits.
• Lighting: explosion-proof hand and helmet lights.
• First aid: oxygen therapy sets, resuscitators and trauma kits.