The generic term SHEVS (smoke and heat exhaust ventilation systems) covers different system technologies that can be used to meet various protection goals.
In general, SHEVS pursue 3 different protection goals according to building law
- Personal security
- Neighborhood protection
- Environmental protection
In addition, there are other goals that need to be considered:
- Property protection
- Third party protection (traffic safety)
- Success liability
- and much more
Smoke extraction includes all technical measures and means to keep escape routes as well as common areas for people in case of fire low in smoke or smoke-free and to improve visibility for the fire department in case of fire. The MRA (mechanical smoke exhaust system) represents a part of the SHEVS, with the smoke exhaust fan for conveying smoke or hot gases forming the center of the system. Because MRAs are typically used in structures, they fall under the European Union's Construction Products Regulation (Bau PVO). Therefore, legal proof must be provided by the person placing the product on the market in the form of a declaration of performance in accordance with the Bauprodukteverordnung. Depending on the operating mode of the product (fire only or fire and ventilation), the product is also subject to the ErP Directive.
This declaration of performance is based on the current harmonized standard DIN ISO 12101-3, which means that products installed in SHEV systems must be designed in accordance with this standard. The standard prescribes how the proof of performance, which must be provided by an accredited laboratory, in-factory inspections, product modifications and technical documentation of SHEV products are to be designed. In addition to the actual SHEV product (the fan), its accessories such as frequency converters, silencers, protective hoods, etc. must be tested for the corresponding fire protection class. For fire gas applications, a distinction is made between different performance classes, which are defined in standards:
| Fire gas class | Temperature °C | Minimum operating time min |
| F200 | 200 | 120 |
| F300 | 300 | 60 |
| F400 | 400 | 90 |
| F400 | 400 | 120 |
| F600 | 600 | 60 |
| F842 | 842 | 30 |