Almost every employer in the UK has a legal duty to provide adequate lighting, yet very few know what number they are being measured against. The answer depends on whether you are asking about the legal minimum (what HSE will enforce) or the design standard (what a competent lighting designer, insurer or tenant will expect). This guide explains both, with the HSE figures in full.
What the law says: regulation 8
Regulation 8 of the Workplace (Health, Safety and Welfare) Regulations 1992 contains three duties:
- Every workplace shall have suitable and sufficient lighting.
- That lighting shall, so far as is reasonably practicable, be by natural light.
- Suitable and sufficient emergency lighting shall be provided where people at work would be especially exposed to danger if the artificial lighting failed.
The regulations do not contain a single lux number. "Suitable and sufficient" is judged against the work being done, and the risk assessment required by the Management of Health and Safety at Work Regulations 1999 should cover lighting hazards. Display screen work adds duties under the Health and Safety (Display Screen Equipment) Regulations 1992. Our workplace regulations guide covers the wider regulations.
Minimum lux levels from HSE: the HSG38 table
HSE's guidance HSG38 Lighting at work is where the commonly quoted "minimum lux levels HSE" come from. It gives two figures for each category of work: an average illuminance for the work area as a whole, and a minimum measured illuminance at any single point. The minimum exists because a good average can hide a dangerously dark spot.
| Activity | Typical locations / types of work | Average illuminance (lux) | Minimum measured illuminance (lux) |
|---|---|---|---|
| Movement of people, machines and vehicles | Lorry parks, corridors, circulation routes | 20 | 5 |
| Movement of people, machines and vehicles in hazardous areas; rough work not requiring any perception of detail | Construction site clearance, excavation and soil work, loading bays, bottling and canning plants | 50 | 20 |
| Work requiring limited perception of detail | Kitchens, factories assembling large components, potteries | 100 | 50 |
| Work requiring perception of detail | Offices, sheet metal work, bookbinding | 200 | 100 |
| Work requiring perception of fine detail | Drawing offices, factories assembling electronic components, textile production | 500 | 200 |
HSG38 also notes that some tasks need more than these figures. Where people are older, the task has low contrast or errors carry serious consequences, more light is justified. It also flags the need to avoid sharp contrasts between a well-lit task area and its surroundings.
How HSE expects the figures to be applied
- Average illuminance is measured on the working plane across the area where the work is done, not across the whole building.
- The minimum applies at any position within that area, so readings must include the darkest spots, not just a few points under fittings.
- For local task lighting, the figures apply to the task itself.
- Glare, flicker, colour rendering and the condition of fittings all form part of "suitable", not just the lux value.
Legal minimum vs good-practice design standards
This is where most confusion arises. An office that measures 250 lux on its desks satisfies the HSG38 figure for "perception of detail" (200 lux). But it falls well short of the 500 lux that BS EN 12464-1:2021 recommends for reading, writing and screen work.
| Space | HSG38 average (minimum) | BS EN 12464-1:2021 maintained |
|---|---|---|
| Corridors and circulation | 20 lux (5 lux) | 100 lux |
| Loading bays | 50 lux (20 lux) | 150 lux |
| Commercial kitchens | 100 lux (50 lux) | 500 lux |
| General offices | 200 lux (100 lux) | 500 lux |
| Technical drawing | 500 lux (200 lux) | 750 lux |
Which one applies to you?
- Enforcement: an inspector from HSE or your local authority (which enforces in most offices, shops and warehouses) will start from regulation 8 and HSG38. Falling below HSG38 is a strong indication of a breach.
- Everything else: landlords, insurers, fit-out specifications, CIBSE guidance (SLL Code for Lighting, LG7 for offices) and new-build designs work to BS EN 12464-1:2021. If you have a lease obligation to maintain lighting "to current standards", or an employee claim about eyestrain, this is the yardstick used.
- Display screen work: the DSE Regulations require lighting that gives adequate contrast without glare. In practice, that points to the BS EN 12464-1:2021 office values with good glare control. See our DSE lighting guide.
Our advice is to treat HSG38 as the floor you must never drop below, and BS EN 12464-1:2021 as the level you should design and maintain to. You can find the full table of design values in our recommended lux levels chart.
Signs your workplace lighting is not sufficient
- Staff complaints of headaches, eyestrain or difficulty reading labels.
- Failed or flickering tubes, dark patches between fittings, or areas lit only by spill from elsewhere.
- Layouts that have changed since the lighting was designed: new racking, partitions or desk rows.
- An LED retrofit carried out on a one-for-one basis without a lighting calculation.
- Near-misses or accidents at steps, loading docks or vehicle routes after dark.
How compliance is demonstrated
The only reliable way to show your lighting meets either standard is to measure it. A lux survey takes readings on a grid across each task area at the correct working-plane height with a calibrated meter. The results are reported as average, minimum and uniformity against HSG38 and BS EN 12464-1:2021 for each space. That record is what you produce for an inspector, insurer or tribunal, and it is the evidence base for your lighting risk assessment.
How often to repeat it depends on the risk and on how often your premises change. Our guide on how often testing should be carried out sets out typical intervals.
Get your workplace light levels measured
Polarity Lux measures workplace light levels for employers across London and the South East, including Hertfordshire, Essex, Kent, Surrey and Berkshire. Every report compares your readings with both the HSE minimums and the BS EN 12464-1:2021 design values, so you know exactly where you stand. Spot checks start from £90 and full office or retail surveys from £175. Book a workplace lighting survey.
Frequently asked questions
What is the minimum lux level for an office according to HSE?
HSG38 gives 200 lux average and 100 lux minimum measured for work requiring perception of detail, such as offices. The good-practice design standard BS EN 12464-1:2021 recommends 500 lux for reading, writing and screen work.
Is there a legal lux level for workplaces in the UK?
No single lux number is written into law. Regulation 8 of the Workplace Regulations 1992 requires suitable and sufficient lighting, and HSE guidance HSG38 sets out the minimum levels it expects for different types of work.
What is the minimum lux level for corridors?
HSG38 gives 20 lux average and 5 lux minimum for circulation routes. BS EN 12464-1:2021 recommends 100 lux maintained for corridors and circulation areas.
Who enforces workplace lighting standards?
HSE enforces in factories, construction and similar premises, while local authority environmental health officers enforce in most offices, shops, warehouses and hospitality premises. Both work from regulation 8 and HSG38.
Does an employer have to provide natural light?
Regulation 8 requires lighting to be by natural light so far as is reasonably practicable. Where that is not possible, suitable artificial lighting must be provided.