The enclosure versions are divided into “pressure shock resistant design” (PSR) and “pressure resistant design (PR)”.
PR pressure resistant design
- The fan casing is under permanent overpressure of more than 0.5 barg and is therefore subject to the Pressure Equipment Directive PED (97/23/EC).
- Depending on the volume and pressure level, various strict type, design and production tests are mandatory pursuant to PED.
- Operating conditions above 1.3 bar (pressure side) are outside the scope of the ATEX Directive (2014/34/EC), therefore simultaneous ATEX conformity is not possible for a PR fan.
PSR pressure shock resistant design
- Apart from the fan’s own pressure increase, the enclosure is not under overpressure, but can withstand a defined explosion pressure in the event of a brief pressure increase (e.g. due to an explosion).
- This version is usually not subject to the Pressure Equipment Directive PED. On principle, ATEX fans according to 2014/34/EC can also be realised in PSR design.
