Lighting risks on the production floor
Manufacturing sites combine fine visual tasks with heavy machinery and vehicle movement, so lighting failures have consequences beyond comfort. The risks we see most often are:
- Stroboscopic effects where flicker from some light sources interacts with rotating machinery, making moving parts appear slower or stationary. HSG38 specifically warns about this.
- Shadowing at machine tools and assembly benches, where the operator or the machine itself blocks overhead light.
- Glare and reflections from polished metal, which hide defects and cause fatigue.
- Low light on inspection stations, leading to missed defects and quality complaints.
- Dirty or degraded luminaires in dusty, oily or hot environments, where output falls faster than expected.
Standards and target lux values
The legal requirement is regulation 8 of the Workplace (Health, Safety and Welfare) Regulations 1992, with HSE guidance in HSG38 Lighting at work. The Provision and Use of Work Equipment Regulations 1998 also require suitable lighting for the safe use of work equipment. BS EN 12464-1:2021 provides task-by-task design values. A representative selection for metalworking and assembly is shown below; the full tables are covered on our BS EN 12464-1:2021 page.
| Task | Maintained illuminance |
|---|---|
| Open die forging; plate machining 5 mm and over | 200 lx |
| Welding; rough and average machining (tolerance 0.1 mm or more) | 300 lx |
| Precision machining and grinding (tolerance under 0.1 mm) | 500 lx |
| Scribing and inspection | 750 lx |
| Assembly: rough / medium / fine / precision | 200 / 300 / 500 / 750 lx |
| Colour inspection (where applicable) | 1000 lx |
Electrical and electronics assembly has its own, higher scale in the standard. Each value comes with uniformity, glare (UGR) and colour rendering (Ra) limits, and the immediate surrounding area must not fall too far below the task value. Our required lux lookup lets you check other tasks quickly.
Who asks for lighting evidence
HSE
Factories are enforced by HSE. Investigations after machinery accidents commonly consider whether the operator could see clearly, including whether stroboscopic effects or shadowing played a part. A documented lux survey and the actions taken from it show that you assessed the risk.
Insurers, auditors and customers
Insurers may ask for lighting evidence as part of risk surveys. Customer quality audits, particularly in automotive, aerospace and medical device supply chains, often look at inspection station lighting. Certification bodies for quality and safety management systems will expect you to show that the working environment, including lighting, is controlled.
What we measure on a factory survey
- Task illuminance at representative machines, benches and inspection points, measured at the actual working plane rather than a notional desk height.
- Average and uniformity across production zones, walkways and vehicle routes.
- Surrounding-area illuminance around high-demand tasks.
- Visible signs of flicker risk, noting light source types near rotating machinery for further assessment.
- Condition of luminaires, including dirt build-up, failures and damaged diffusers.
- Emergency escape lighting and, where hazardous processes exist, high-risk task area lighting against BS EN 1838:2024, which requires at least 10% of normal maintained illuminance or 15 lx, whichever is greater.
Our report gives a pass or fail against each task value and prioritises remedial work, so you can tell the difference between a cleaning job and a redesign.
Line changes, mezzanines and LED upgrades
Moving a production line, adding a mezzanine or swapping high-bay fittings can each change what reaches the working plane. Local task lighting is often the cheapest fix for a single failing station, while widespread low readings point to a layout or maintenance problem. Read about LED upgrades before committing to a project.
Hot, dusty and wet environments
Foundries, paint shops, woodworking areas and wash bays shorten luminaire life and coat optics, so light output can fall well below design between maintenance visits. Luminaires in these areas should have an ingress protection rating suited to the environment, and cleaning should be part of planned maintenance. Repeat surveys show how quickly output is degrading and help set a realistic cleaning interval, rather than relying on the maintenance factor assumed when the scheme was designed.
Book a manufacturing lighting survey
We survey factories and production sites throughout London and the South East, including Essex, Kent and Hertfordshire. See our factory lux survey service and industrial lighting surveys. Industrial surveys start from £320, with the final price confirmed before booking. Book a factory survey online.
Frequently asked questions
What lux level is needed for factory work?
It depends on the task. BS EN 12464-1:2021 recommends 300 lux for welding and general machining, 500 lux for precision machining and 750 lux for scribing and inspection. Assembly ranges from 200 to 750 lux depending on how fine the work is.
What is the stroboscopic effect and why does it matter?
It is when flickering light makes rotating machinery appear to move slowly or stand still. HSG38 warns that this can be dangerous, so light sources near rotating equipment should be chosen and checked with this in mind.
Do we need emergency lighting at hazardous machines?
Where a process could be dangerous if the lights failed, high-risk task area lighting is needed so the operator can shut down safely. BS EN 1838:2024 sets this at 10% of normal maintained illuminance or 15 lux, whichever is greater.