Commercial ventilation requirements in the UK: what the rules say

Two different rules, often confused

People asking what ventilation a commercial building needs are usually mixing two rules. The first is a duty on whoever runs the workplace, which applies every day the building is occupied. The second is a technical requirement on building work, which applies when a building is built, extended or materially altered. A building can pass the second and still breach the first if the plant is neglected.

The workplace duty: regulation 6

Regulation 6 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires effective and suitable provision to ensure every enclosed workplace is ventilated by a sufficient quantity of fresh or purified air. Where plant provides that ventilation, regulation 6(2) says it must include an effective device giving visible or audible warning of failure where this is necessary for health or safety.

The regulation is deliberately non-numerical. In practice that means the employer or building manager has to be able to show that the system works, is maintained and that failure would be noticed. HSE's Approved Code of Practice and guidance, L24, explains how the Workplace Regulations are applied.

The building work rule: Approved Document F Volume 2

In England, Part F of Schedule 1 to the Building Regulations sets the ventilation requirement and Approved Document F Volume 2 gives practical guidance for buildings other than dwellings, with the purpose of maintaining indoor air quality. The version currently published took effect on 15 June 2022, with transitional arrangements for work already notified before that date.

Wales, Scotland and Northern Ireland have their own regulations and guidance, so a UK-wide estate needs each nation checked separately.

What this means for a plant decision

Replacing or adding mechanical ventilation, heat recovery units or air handling plant is the point at which both rules meet: the design has to be right for the building regulations if the work is notifiable, and the system then has to keep working for regulation 6. Three practical questions follow. Who set the design airflow for each space? Who commissioned and balanced the system, and is there a record? Who maintains the filters and checks the fan failure alarm?

For system types see commercial ventilation and MVHR and air handling units, and for what planned maintenance covers see HVAC planned preventive maintenance.

Sources and last checked

Checked on 18 October 2026. Regulations and guidance are revised, so confirm the current edition before you rely on it.

• The Workplace (Health, Safety and Welfare) Regulations 1992, regulation 6 (ventilation)
• GOV.UK: Ventilation, Approved Document F (Volume 2: buildings other than dwellings)
• HSE: L24 Workplace health, safety and welfare Approved Code of Practice and guidance