Contents (6 sections)
In what order to select luminaires
Quick answer
For indoor work places, TCVN 7114-1:2008 specifies four criteria for each type of area and task: maintained illuminance, uniformity, UGR glare limit and colour rendering index Ra. First, select the level from the table in Clause 5 for the correct area. Then choose the luminaire type according to the environment (dust, humidity, mounting height), and calculate the number of luminaires in the lighting design documents. For emergency lighting see exit signs and emergency luminaires; for luminaires in damp or dusty areas see waterproof, dustproof and explosion-proof luminaires.
TCVN 7114-1:2008 is identical to ISO 8995-1:2002/Cor 1:2005. The standard sets out requirements and does not give guidance on how to design the lighting system for each specific location (Clause 1); the number of luminaires, their wattage and layout are still calculated by the design engineer.
The four criteria of TCVN 7114-1
All illuminance values in the standard are maintained illuminance: the average illuminance on the working surface must not fall below the value in the table at any time during use, including after the luminaires have lost luminous flux and become soiled. The standard therefore requires a design maintenance factor of not less than 0.7 (clause 4.8).
| Criterion | Requirement | Clause |
|---|---|---|
| Maintained illuminance Em | Not less than the value in Clause 5; not below 200 lux for continuously occupied work places. May be raised or lowered by at least one step on the scale where visual conditions differ from those assumed | 4.3, 4.3.1 |
| Illuminance scale | 20 – 30 – 50 – 75 – 100 – 150 – 200 – 300 – 500 – 750 – 1000 – 1500 – 2000 – 3000 – 5000 lux | 4.3.2 |
| Uniformity Uo (Emin/Eav) | Task area ≥ 0.7; immediate surrounding area ≥ 0.5 | 4.3.4 |
| Glare UGR | The UGR of the installation must not exceed UGR_L in Clause 5; scale 13 – 16 – 19 – 22 – 25 – 28 (the lower the number, the stricter) | 4.4.2 |
| Colour rendering Ra | Lamps with Ra < 80 should not be used for regularly occupied work places, except in high-ceiling workshops with luminaires mounted above 6 m (see the section below) | 4.6.2 |
| Maintenance factor | Not less than 0.7 | 4.8 |
Source: TCVN 7114-1:2008 Clause 4; full-text republication, cross-checked against two or more sources.
- Immediate surrounding area: 500 lux where the task area illuminance is 750 lux or more; 300 lux where it is 500 lux; 200 lux where it is 300 lux; at 200 lux or below, equal to the task area illuminance (table in clause 4.3.3).
Illuminance for production areas
The table in Clause 5 is divided by industry and process. The rows most often encountered in mechanical and electrical workshops:
| Area, task | Em (lux) | UGR_L | Ra |
|---|---|---|---|
| Production machinery with frequent manual operation | 300 | 25 | 80 |
| Forging, welding, bench fitting | 300 | 25 | 60 |
| Rough and medium machining (tolerance > 0.1 mm) | 300 | 22 | 60 |
| Precision machining (tolerance < 0.1 mm) | 500 | 19 | 60 |
| Mechanical assembly workshop: coarse parts | 200 | 25 | 80 |
| Mechanical assembly workshop: medium parts | 300 | 25 | 80 |
| Mechanical assembly workshop: small parts | 500 | 22 | 80 |
| Mechanical assembly workshop: precision work | 750 | 19 | 80 |
| Surface treatment and painting | 750 | 25 | 80 |
| Cable manufacturing; winding of large coils | 300 | 25 | 80 |
| Electrical equipment assembly: medium parts (e.g. switchboards) | 500 | 22 | 80 |
| Electrical equipment assembly: precision parts (e.g. measuring instruments) | 1000 | 16 | 80 |
| Electronics workshops, testing, adjustment | 1500 | 16 | 80 |
Swipe sideways to see all columns.
Source: TCVN 7114-1:2008, table in Clause 5, groups 6 (general production), 7 (electrical industry), 14 (metalworking); full-text republication, all cells consistent across sources.
Warehouses, circulation areas and ancillary rooms
Ancillary areas in a factory have lower levels, but where people work regularly the level must still be raised according to the notes in the table.
| Area | Em (lux) | UGR_L | Ra | Notes in the standard |
|---|---|---|---|---|
| Circulation areas, corridors | 100 | 28 | 40 | Provide a transition zone at entrances |
| Stairs | 150 | 25 | 40 | — |
| Warehouses, cold stores | 100 | 25 | 60 | 200 lux if continuously occupied |
| Packing and dispatch areas | 300 | 25 | 60 | — |
| Control stations | 150 | 22 | 60 | 200 lux if continuously occupied |
| Switchgear rooms | 200 | 25 | 60 | — |
| Cloakrooms, bathrooms, toilets | 200 | 25 | 80 | — |
| Canteens | 150 | 25 | 40 | — |
| General offices | 500 | 19 | 80 | — |
Swipe sideways to see all columns.
Source: TCVN 7114-1:2008, table in Clause 5, groups 1 (general areas) and 22 (offices).
- The table has no separate row for high-rack warehouses; the value for high-rack warehouses is taken from the project design documents, not inferred from the "warehouses" row.
- Plants with a control room: the standard lists a control room row only in the power station group (500 lux, UGR 16, Ra 80); for other factories, refer to the design documents.
High-ceiling workshops: luminaires mounted above 6 m
TCVN 7114-1:2008 (clause 4.6.2) allows an exception on colour rendering for high-ceiling workshops and outdoor lighting with industrial luminaires mounted above 6 m: Ra ≥ 80 is not mandatory as it is for other interiors where people work or stay for long periods. Nevertheless, measures must still be taken to provide high colour rendering lighting at continuously occupied work places and at locations where safety colours must be clearly recognised. Many rows in the table marked "high-ceiling workshops see 4.6.2" refer precisely to this exception.
The higher the mounting height, the harder it is to achieve a uniformity of 0.7 on the working surface with few luminaires; the number of luminaires, beam angles and spacing are calculated in lighting design software using the photometric data of the exact luminaire model, not inferred from wattage.
Choosing the luminaire type by area
Once the required illuminance level is known, the luminaire type is chosen by mounting height and environment. The industrial luminaires category is divided into high-bay luminaires for high-ceiling workshops, LED floodlights and industrial reflector luminaires; office and ancillary areas use LED luminaires such as tubes and panels.
- Damp, dusty and wash-down areas: select by IP code, see waterproof, dustproof and explosion-proof luminaires.
- Escape routes, stairs: exit signs and emergency luminaires according to the electrical requirements in the article on exit signs and emergency luminaires.
- Supply cables for luminaires: for cross-section and voltage drop see selecting low-voltage cables for building projects; for lighting, TCVN 9207:2012 (Table 9) limits voltage drop to 5 %.
- Hoang Nhat is an authorised distributor of Rang Dong LED lighting and an official sales agent of Paragon; to send the luminaire list from the drawings, see preparing a BOQ to receive a quotation.
Sources and scope
- TCVN 7114-1:2008 (ISO 8995-1:2002/Cor 1:2005) Clause 1, clauses 4.3, 4.3.1–4.3.4, 4.4.2, 4.6.2, 4.8 and the table in Clause 5 — full-text republication, cross-checked against two or more sources, validity status checked on 14/10/2026
- TCVN 9207:2012 Table 9. Compiled by Hoang Nhat
- not a substitute for lighting design