Explosion protection and ATEX

Usually not. A common concern is that flammable gases could create a flammable atmosphere in the event of leakage. However, this fear is usually unfounded: The leak rate necessary to create a flammable atmosphere (ATEX zone) would be at a scale of g/min, amounting to tons per year. This is many times higher than the leak rates of some g/year that are usually discussed in refrigeration and are relevant, for example, for the F-Gas Regulations.
Therefore, the usual leak rates of refrigeration systems are irrelevant for ATEX, because they are not in the magnitude to create a flammable atmosphere around the compressor.
(last revision: 08.2025)

Enhanced tightness is a measure of long-term tightness, as defined in the EN1127-1 standard (Explosive atmospheres - Explosion prevention and protection). Connections and components of enhanced tightness have sufficiently low leak rates that they cause no ATEX zone around them in the long term – even if a flammable gas (e.g. A3 refrigerant such as R290/propane) is inside.
All BITZER hermetic and semi-hermetic compressors are designed and tested for enhanced tightness in accordance with EN1127-1 – meaning that no ATEX zone needs to be assumed around the product, even in the case of flammable gas inside (see operating instructions KB-100). Dedicated ATEX compressors are therefore only necessary in very special circumstances.
(last revision: 08.2025)

In the EU, this is considered a workplace safety issue. Therefore, the user of the refrigeration system has to determine whether an ATEX zone has to be assumed. This consideration is part of the work place risk assessment, which in most cases is necessary, anyway. If in doubt, the user should consult with the system manufacturer – this is advisable anyway, as the results of the manufacturer’s risk assessment should be integrated into the user’s risk assessment.
Manufacturers of components (e.g. BITZER) are not allowed to provide direct consultation on users’ systems. However, BITZER hydrocarbon training courses may provide useful technical background information, also on risk assessments (see SCHAUFLER Academy).
It should be avoided wherever possible that someone has to work in an ATEX zone (see 1999/92/EC (ATEX 137)).
Whether or not an ATEX zone exists is a result of the workplace risk assessment and should not be determined by the refrigerant.
(last revision: 08.2025)

Primarily by ensuring the refrigerant remains safely inside the system by using components with enhanced tightness. If enhanced tightness is not possible, enforced ventilation in an ATEX-compliant design may suffice to prevent the formation of an ATEX zone.
If this is insufficient, a safety system with gas warning sensors in ATEX design should be installed. This system switches off the refrigeration system and other electrics and switches on alarms, flashing lights, enforced ventilation, etc. Such a safety system prevents explosions and warns people against entering into a flammable atmosphere.
All of this can be achieved without using dedicated ATEX compressors and other components for the refrigeration system.
(last revision: 08.2025)

One basic problem is that if a dedicated ATEX compressor is ordered, but standard electrical components are used in the rest of the refrigeration system, liability issues might arise: It could appear as though the user, who is responsible for the ATEX assessment, knew that ATEX components were necessary, but did not install them throughout the system.
Therefore, if the user’s risk assessment concludes that no ATEX zone will develop, it is often better to purchase standard compressors with enhanced tightness rather than dedicated ATEX compressors.
If an ATEX compressor is required nonetheless (e.g. to avoid possible ignition sources even outside an ATEX zone, or to fulfil a request by the insurance company), this decision should be documented in the user’s risk assessment.
However, if the user’s risk assessment concludes that the system will operate in an ATEX zone, this concerns more than just the compressor: Various dedicated ATEX components are necessary (2014/34/EU (ATEX 114)). Additionally, all installation, servicing, etc. must be carried out by ATEX-qualified personnel. For example, if an electrical ATEX component is installed by someone who is not qualified, its ATEX type label becomes invalid.
(last revision: 08.2025)

For use in ATEX zones 1 and 2, BITZER offers:
- ECOLINE semi-hermetic reciprocating compressors: 2KES(P)-05.EX .. 8FE(P)-70.EX
- CS compact screw compressors: CSH(P)6553-35.EX .. CSH(P)9513-320.EX
- OS open drive screw compressors: OS.7441-EX .. OS.A7472-EX
For customers who want to have (or are asked to have) an ATEX hydrocarbon compressor with no specified ATEX zone, BITZER offers an ATEX special design .X3 for ECOLINE and CS compressors (device category 3, mechanical only).
For use in ATEX zone 2, BITZER offers an ATEX special design .X2 for ECOLINE and CS compressors (device category 3, mechanical and electrical).
For details, see brochures KP-180 (ECOLINE) and SP-170 (CS) as well as operating instructions SB-509 (OS).

Compressors for use in specific ATEX zones have a detailed specification concerning the gas group, temperature class, etc. They are offered via a dedicated sales process to ensure compliance with the application requirements.
(last revision: 08.2025)