A lux survey is only as useful as the report it produces. A report that lists a handful of readings with no reference to the standard, the measurement height or the meter used will not stand up when an insurer, inspector or tenant's surveyor looks closely. This guide walks through each section a compliant lux survey report should contain, why it matters and how to put the report to work.
What a compliant lux survey report contains
1. Site, scope and conditions
- Premises address, areas surveyed (and any excluded), client and surveyor names.
- Date and time of the survey, and whether readings were taken with daylight excluded (typically after dark) or with daylight contribution noted separately.
- State of the installation on the day: lamps failed, fittings dirty, controls in override, furniture or racking layout.
Conditions matter because the same room can read 300 lux at midday and 180 lux at 7pm. Compliance with BS EN 12464-1:2021 is normally assessed on the electric lighting, so a report that does not state how daylight was handled is ambiguous.
2. Instrument details and calibration
The report should identify the lux meter by make, model and serial number and state the date of its last calibration. Precision meters are classified under DIN 5032-7 (classes L, A, B and C) according to their spectral (V(λ)) match, cosine correction and linearity. For compliance work, a Class B meter or better is the accepted minimum. A cheap meter or a phone app can misread modern LED sources by a wide margin. Calibration should be traceable and recent, normally within the last 12 months. Our guide to lux meters explains the classes.
3. Measurement grid and reference plane
Each area should show the grid of measurement points, ideally on a marked-up plan, and the height at which readings were taken. BS EN 12464-1:2021 sets out a method for grid spacing based on the size of the area, so that larger rooms get proportionally more points without gaps where dark patches hide. Typical reference planes are:
- around 0.75 m above floor level for desks and general work surfaces;
- floor level for corridors, stairs, car park traffic lanes and warehouse gangways;
- vertical planes for rack faces, whiteboards and shelving;
- floor level along escape routes for emergency lighting checks.
Readings taken at the wrong height can change the result by 20% or more. For the method in detail, see how lux is measured.
4. Results: average, minimum and uniformity
For each area, the report should present:
- Eav: the average measured illuminance across the grid;
- Emin: the lowest single reading;
- Uo: uniformity, calculated as Emin divided by Eav;
- the individual point readings, so the calculation can be checked.
Uniformity is often where an installation fails. An office averaging 520 lux with a minimum of 210 lux has a Uo of 0.40, below the 0.60 typically required for office tasks, even though the average comfortably exceeds 500 lux.
5. Comparison with the standard: pass or fail
Every area should be assigned a task category and compared with the correct benchmark. That is the maintained illuminance and uniformity from BS EN 12464-1:2021, the HSG38 minimums for the legal baseline, or BS EN 1838:2024 and BS 5266-1:2025 for emergency lighting. A clear pass or fail per area, rather than an overall verdict, is what makes a report usable.
| Area | Task category | Required Em / Uo | Measured Eav | Measured Uo | Result |
|---|---|---|---|---|---|
| Open plan office, 2nd floor | Writing, typing, reading | 500 lux / 0.60 | 545 lux | 0.66 | Pass |
| Main corridor | Circulation | 100 lux / 0.40 | 84 lux | 0.31 | Fail |
| Stock room | Store, continuously occupied | 200 lux / 0.40 | 230 lux | 0.45 | Pass |
Illustrative format only; not a real site.
A good report also comments on maintenance factor. A newly installed scheme that only just meets the maintained value today will drop below it as lamps age and fittings collect dust.
6. Photographs
Dated photographs of each area record the layout, fittings and any defects at the time of the survey. They are invaluable if the report is used in a dispute months later, for example over whether a tenant altered the lighting.
7. Recommendations
Every failure should come with a practical remedy, ranked by cost: replace failed lamps, clean diffusers, adjust controls, relocate fittings, add task lighting or redesign. A report that just says "fail" leaves you to work out the answer yourself. See common lighting failures for the causes we see most often.
8. Sign-off
The report should be signed and dated by the surveyor, with the company details, so it can be relied on by third parties.
How to use your lux survey report
Insurers
Liability insurers and risk surveyors increasingly ask for evidence that slip, trip and vehicle-movement risks are controlled. A dated report with pass results, or a completed action plan for the fails, answers the question directly.
Landlords and tenants
Leases often require lighting to be maintained in good working order or to a stated standard. A report at the start and end of a lease gives both parties an objective baseline for dilapidations. Landlords of HMOs and rented housing can use it to show communal areas and escape routes are adequately lit.
HSE and local authority inspectors
If lighting is raised during an inspection or after a complaint, a report showing measured compliance with HSG38 and BS EN 12464-1:2021 is the strongest evidence that you have met regulation 8 of the Workplace Regulations 1992. It also supports your written risk assessment.
Premises licensing
Premises licences under the Licensing Act 2003 sometimes carry conditions on lighting levels, for example in external areas or during closing time. A lux report gives the licensing authority and police measured figures rather than opinion.
Get a report that stands up to scrutiny
Every Polarity Lux report includes the grid, reference plane, calibrated meter details, average, minimum and uniformity for each area, a pass or fail against the named standard, photographs and prioritised recommendations. We survey across London and the South East, including Hertfordshire, Essex, Kent and Surrey. Insurance and dilapidations reports start from £190 and premises licensing reports from £160. Book your lux survey.
Frequently asked questions
What should a lux survey report include?
It should include site and survey conditions, meter make, serial number and calibration date, the measurement grid and reference plane height, average, minimum and uniformity for each area, pass or fail against a named standard, photographs, recommendations and the surveyor's sign-off.
What does uniformity mean in a lux report?
Uniformity (Uo) is the minimum measured illuminance divided by the average. BS EN 12464-1:2021 typically requires 0.60 for office tasks and 0.40 for circulation areas, so an area can fail on uniformity even when its average is high enough.
What class of lux meter should be used for a compliance survey?
A calibrated meter of DIN 5032-7 Class B or better is the accepted minimum for compliance work, with a traceable calibration normally within the last 12 months. Phone apps and uncalibrated meters are not suitable.
Will my insurer accept a lux survey report?
A dated, signed report showing measured readings against a recognised standard, with an action plan for any failures, is the type of evidence insurers and risk surveyors look for. Check your insurer's specific requirements before booking.
Why are lux surveys often carried out after dark?
Compliance with BS EN 12464-1:2021 is normally assessed on the electric lighting alone, so readings are taken with daylight excluded. Otherwise daylight can mask an installation that would fail on a winter afternoon.