What HSE expects from employers
HSE does not publish a statutory list of lux levels. Its expectations come from three places: the legal duty in regulation 8 of the Workplace Regulations 1992 to provide suitable and sufficient lighting; the duty under regulation 3 of the Management of Health and Safety at Work Regulations 1999 to carry out a suitable and sufficient risk assessment; and HSE's own guidance, HSG38 Lighting at work (second edition, 1997), which is still current and free to download from HSE.
HSG38 is guidance rather than law or an Approved Code of Practice, but it is the document an HSE inspector or local authority officer is most likely to reach for when deciding whether lighting is adequate. Its figures are minimums for health and safety. For visual comfort and task performance, inspectors and designers generally expect you to meet BS EN 12464-1:2021 as well.
Lighting in your risk assessment
HSG38 treats lighting as a hazard to be assessed like any other. A practical lighting risk assessment covers:
- The tasks. How much detail must be seen, at what speed, and how costly or dangerous is an error? Reading a gauge, inspecting a weld and walking a corridor need very different light.
- The hazards. Moving vehicles, rotating machinery, steps and level changes, hot surfaces and sharp edges all raise the stakes if people cannot see clearly.
- The people. Older workers generally need more light and are more sensitive to glare; people with visual impairments may need specific adjustments.
- Glare and flicker. Bright luminaires, reflections on screens and stroboscopic effects on rotating machinery can be as dangerous as too little light.
- Transitions. Large differences between adjacent areas, such as a bright warehouse and a dark yard, leave eyes unable to adapt in time.
- Failure. What happens if the lighting goes off? Where people would be specially exposed to danger, emergency lighting is required.
- Maintenance. Dirty fittings, failed lamps and obstructed luminaires reduce light over time, so checks should be scheduled.
Record significant findings, and review the assessment when layouts, processes, occupants or lighting change, including after an LED upgrade.
The HSG38 minimum illuminance table
Table 1 of HSG38 gives two figures for each type of activity: an average illuminance for the work area as a whole and a minimum measured illuminance at any point within it. Both matter. An average alone can hide dark spots where someone could trip or misread a control.
| Activity | Typical locations | Average (lx) | Minimum measured (lx) |
|---|---|---|---|
| Movement of people, machines and vehicles | Lorry parks, corridors, circulation routes | 20 | 5 |
| Movement in hazardous areas; rough work not requiring perception of detail | Construction site clearance, excavation, 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, electronic component assembly, textile production | 500 | 200 |
Notice that the HSG38 figure for offices, 200 lx average, is well below the 500 lx required by BS EN 12464-1:2021 for writing, typing and reading. Meeting HSG38 shows the lighting is not unsafe; it does not show that it is good enough for sustained desk work. Our recommended lux levels chart sets the two side by side.
Illuminance ratios between adjacent areas
Table 2 of HSG38 limits the ratio between a working area and the area next to it, so that eyes can adapt as people move between them:
| Situation | Example | Maximum ratio (working : adjacent) |
|---|---|---|
| Each task individually lit, surrounding area lit to a lower level | Local task lighting in an office | 5 : 1 |
| Two adjacent working areas, one lit to a lower level | Localised lighting in a works store | 5 : 1 |
| Two working areas at different levels, separated by a barrier, with frequent movement between them | Storage area inside a factory and a loading bay outside | 10 : 1 |
HSG38's own example: an interior lit to 500 lx next to an area that needs only 20 lx for movement gives a ratio of 25 : 1, which is too great. Applying the 10 : 1 limit, the adjacent area should be lit to at least 50 lx. This is one of the most frequent issues we find at warehouse doors and goods-in yards; see warehouse lighting standards.
Other HSE expectations in HSG38
- Glare control: luminaires and windows positioned or shielded so they do not dazzle, and screens arranged to avoid reflections.
- Stroboscopic effect: avoid lighting that makes rotating machinery appear stationary. Poor-quality LED drivers can reintroduce this problem.
- Colour: where colour coding is used for safety, such as cables or pipework, the light source must render colours well enough to tell them apart.
- Emergency lighting: where failure of normal lighting would create risk, with an independent supply.
- Maintenance: cleaning and lamp replacement planned so levels do not fall below the minimums between visits.
Showing an inspector you comply
When an inspector asks about lighting, the strongest answer is a lighting risk assessment backed by measured results. A grid-based lux survey shows the average and minimum in each area, so you can compare directly with both HSG38 tables and the BS EN 12464-1:2021 task values. It also flags ratio problems between adjacent areas, which spot readings tend to miss. For the method, see how lux is measured.
Book an HSE-focused lux survey
We survey workplaces across London, Hertfordshire, Essex, Kent, Surrey and the rest of the South East, and report every area against HSG38 minimums and BS EN 12464-1:2021 so you can see at a glance what is safe, what is comfortable and what needs work. Book a survey to put measured evidence behind your risk assessment.
Frequently asked questions
Is HSG38 a legal requirement?
No. HSG38 is HSE guidance, not law or an Approved Code of Practice. It is, however, the main reference inspectors use to judge whether lighting is suitable and sufficient under regulation 8.
What is the HSG38 minimum lux level for an office?
HSG38 gives 200 lx average and 100 lx minimum measured for work requiring perception of detail, which includes offices. BS EN 12464-1:2021 sets 500 lx for general office tasks, so most offices are designed to the higher figure.
Why does HSG38 give a minimum as well as an average?
An average can conceal dark spots. The minimum measured value ensures there is no point in the work area where lighting falls low enough to create a safety risk.
Do I need to include lighting in my risk assessment?
Yes. The Management of Health and Safety at Work Regulations 1999 require a suitable and sufficient risk assessment, and HSE expects lighting hazards such as poor levels, glare and failure of lighting to be considered.