8.4.2 Mechanical extract ventilation systems (MEV)
Bathroom and kitchen extract fans providing decentralised extract ventilation (dMEV) or central mechanical extract ventilation (cMEV) and may be continuous or intermittent, depending on design and location.
Definitions for MEV
| Air valve (extract) | Wall or ceiling mounted fittings used to balance the flow rate of air between rooms; may be referred to as grilles |
| cMEV | Central mechanical extract ventilation system providing simultaneous ventilation to reduce excess moisture using multiple extraction points |
| dMEV | Decentralised mechanical extract ventilation system providing ventilation to reduce excess moisture using single extraction point |
| Exhaust ductwork | Carries air from the fan unit and exhausts it to the external atmosphere |
| MEV | A generic term relating to both cMEV and dMEV |
| Service ductwork extract | Carries air between the air valves and the MVHR fan unit |
| Terminal fittings | Located on the outside of the building to finish the intake and exhaust ductwork |
Clauses for 8.4.2 Mechanical extract ventilation systems (MEV)
- 8.4.2 Figure reference table
- 8.4.2.1 Compliance
- 8.4.2.2 Provision of information
- 8.4.2.3 System design
- 8.4.2.4 Acoustics
- 8.4.2.5 Building integration
- 8.4.2.6 Ductwork
- 8.4.2.7 Fixing and jointing of ductwork
- 8.4.2.8 Access and operation
- 8.4.2.9 Electrical installation requirements
- 8.4.2.10 Handling and storage
- 8.4.2.11 Commissioning and balancing
- 8.4.2.12 Sequence of work
Last updated: 2nd January 2025