General safety references
The design, operation and maintenance of refrigeration systems with flammable refrigerants are subject to particular safety regulations. They include, among others, special safety devices against exceeding the pressure and particularities in the design and arrangement of the electrical operating equipment.
Moreover, measures must be taken that guarantee risk-free ventilation in the event of a refrigerant leak, to prevent the formation of an ignitable gas mixture. The specifications are established in standards (e.g. EN378, ISO5149). However, in view of the high requirements and product liability, a risk assessment by a notified body or jointly with a notified body is in general recommended.
Depending on the design and the refrigerant charge, an assessment according to EU Framework Directives 2014/34/EU (ATEX 95) and 1999/92/EC (ATEX 137) may be necessary. The operation of the system and personal protection are usually subject to national regulations on product safety, operating reliability and accident prevention. To this end, separate agreements between the contractor and the end user must be made. The required risk assessment of the system must be prepared by the system manufacturer. However, the hazard assessment for installation, operation and maintenance of the system is the responsibility of the end user.
DANGER
Risk of explosion and thus danger to life if refrigerant leaks and in the presence of an ignition source!
A refrigerant can ignite and also form an explosive atmosphere depending on its concentration in the air!
Avoid open fire and ignition sources in the machinery room and in the hazardous zone!
- Observe the flammability limits in air (at 20°C and 1013 mbar, see also safety data sheet of the substance), e .g:
- R1234yf between 6.2 and 12.3% by volume
- R454C between >7 and <15% by volume
- R455A between 11.8 and 12.9% by volume
- Observe ignition temperatures in air (at 20°C and 1013 mbar), e. g.:
- R1234yf: 405°C
- Ventilate the machinery room according to EN378 or install an extraction device.
- To open the pipes, use only pipe cutters; do not use an open flame!
- Install components from which refrigerant may leak (e.g. low and high pressure cut-out) only outside the switch cabinet!
If it is guaranteed that the compressor will not be operated in an Ex zone, an ATEX or Ex design is not required.
This can be guaranteed, for example, by:
- Ventilation that does make an explosive or flammable atmosphere impossible even if the greatest possible leak is assumed.
- Shutting off the electric consumers clearly below the lower explosive limit (LEL or LFL), which will require a gas sensor. Typically, the shut-off value of the sensor for the system is set to a maximum of 20% of the LFL. For information on this, please consult national regulations and notified bodies.