A refrigerant gas detector watches plant rooms, machinery rooms and cold stores for leaks from refrigeration, air conditioning and heat pump systems. We supply, install and service refrigerant and ammonia gas detection across Ireland, from a single sensor in a plant room to multipoint and sampling systems for large cold stores.
A refrigerant leak costs money, harms the environment and, in an enclosed room, can be a safety risk. Many fluorinated refrigerants are much heavier than air. The International Chemical Safety Card for HFC-134a gives it a relative vapour density of 3.5 and warns that a harmful concentration will be reached very quickly on loss of containment. In a small plant room or walk-in cold store, a leak can build up at floor level without anyone noticing.
Ammonia is different. Its safety card describes a gas with a pungent odour that is lighter than air. The HSA’s 2026 Code of Practice for the Chemical Agents Regulations gives anhydrous ammonia occupational exposure limit values of 20 ppm over an 8 hour reference period and 50 ppm over 15 minutes. An ammonia gas detector measures the concentration so you can act on it, rather than relying on smell. For CO2 refrigeration systems, see our CO2 gas detection page.
Article 6 of the EU F-gas Regulation, (EU) 2024/573, deals with leakage detection systems. It says operators of stationary refrigeration, air conditioning and heat pump equipment containing fluorinated greenhouse gases in quantities of 500 tonnes of CO2 equivalent or more must ensure the equipment is provided with a leakage detection system that alerts the operator or a service company to any leak. It also says those systems must be checked at least once every 12 months to make sure they work properly.
EN 378 is the European standard for safety and environmental requirements for refrigerating systems and heat pumps. Part 3 covers the installation site, meaning the plant space, services and personal protective equipment. Whether your system needs detectors under the standard, and at what setting, depends on the refrigerant, the charge and the room, so we work from your refrigeration contractor’s or designer’s assessment.
Sensor height follows the gas. Honeywell’s technical guide to gas detection advises mounting detectors at high level for lighter than air gases such as methane and ammonia, preferably with a collecting cone, and at low level for heavier than air gases. Sensors for HFC refrigerants such as R-134a therefore go low, near the plant and in any pit or low point. Ammonia sensors go high, above compressors and valve stations.
The same guide warns that process conditions matter: gas released from a line under pressure or at a different temperature may not behave as it normally would. We look at the plant itself, not only the gas, before we fix positions.
| Gas | Relative vapour density (air = 1) | Behaviour when released | Typical sensor position |
|---|---|---|---|
| HFC-134a (R-134a) | 3.5 | Heavier than air, collects low | Low level, near the plant and in pits or low points |
| Carbon dioxide (R-744) | 1.5 | Heavier than air, may accumulate in lowered spaces | Low level, near the plant and in cellars or pits |
| Ammonia (R-717) | 0.60 | Lighter than air, rises | High level, above compressors and valve stations |
Refrigerant detection is usually part of a wider system that also covers fuel gas or oxygen. Options from our range include:
We install and commission the sensors, panel and alarms, and link them to extract fans or plant shutdown where the design calls for it. At handover we train your staff on operation and on resetting after an alarm.
If your system falls under the F-gas leakage detection rule above, its check at least once every 12 months fits naturally into a maintenance contract. We calibrate with certified test gases and give you a record of each visit. Our engineers also service refrigerant detectors from many other manufacturers.
No. The F-gas leakage detection rule applies to the equipment types it lists at 500 tonnes of CO2 equivalent or more. Smaller systems may still need detectors under EN 378 or your own risk assessment, depending on the refrigerant, the charge and the room. Your refrigeration contractor can confirm which applies.
Some sensors respond to a group of refrigerants, others are specific to one. We match the sensor to the refrigerant in your system and calibrate it for that gas.
Yes. The panel’s relays can start extract fans, shut down plant or send a signal to your BMS when a sensor reaches its alarm level.
Follow the site emergency procedure. Leave the area, get to fresh air and call the emergency services if anyone is affected. Do not go back in until the area has been checked and made safe.
Yes. We service, calibrate and repair gas detection equipment from many manufacturers, and can extend an existing system or replace it when parts are no longer available.
Tell us the refrigerant, the charge and the room it serves, and we will recommend detection to suit. Call 01 289 7720 or email info@vistec.ie.
© 2026 Vistec Gas Detection Ltd
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