Appropriate lighting in a workplace can have a profound effect on worker safety, as well as the bottom line. Offices, retail locations and industrial facilities can all benefit from the added productivity, enhanced safety, and improved employee morale associated with appropriate lighting. Proper illumination and electrical installation practices will also avoid possible Occupational Safety & Health Administration (OSHA) citations. Newer lighting technologies, such as light emitting diode (LED), reduce electrical demand and save energy and money.
Lightbulbs and Illumination
The tungsten-filament incandescent bulb was introduced in the 1880s with a dramatic effect on the industrial revolution already underway. It offered a pleasing quality of light, but was very energy inefficient. The mercury-vapor fluorescent bulb came into widespread use during World War II and was significantly more energy-efficient. While fluorescent bulbs used only one-quarter of the energy of incandescent bulbs, the quality of light was lacking for many purposes. The LED light bulb has come into common use over the last two decades – providing high quality light while only using half the electricity of a fluorescent bulb.
The brightness of a light source is measured in lumens and the power consumption in watts. A 60-watt incandescent bulb emits about 800 lumens; while the same 800 lumens can be provided with about 15 watts from a fluorescent bulb or only eight watts from an LED bulb. Reducing the required wattage reduces the electrical demand.
Illuminance describes the amount of light hitting a surface and is the basis for OSHA illumination regulations and measuring the brightness of workplaces. Illuminance may be expressed in the U.S. customary unit of foot-candle (FC) or the metric unit of Lux (lx). One foot-candle is the approximate amount of light produced by a wax candle falling on a square foot surface and lux is the amount of light falling on a square meter. Therefore, one FC equals 10.76 lx.
Lighting is effective only when it illuminates the intended work surface. We call this task lighting and it is important in making an operation safe. Detailed assembly of small parts often require more light than say a warehouse.
OSHA Regulations
OSHA has established minimum illumination levels for several areas of operation in the workplace, as well as electrical safety standards related to lighting. The most cited OSHA lighting standard is the construction industry Illumination Standard found in Title 29 CFR 1926.56. This Standard includes Table D-3 below – specifying the illumination required for different areas of operation.
TABLE D-3 – Minimum Illumination Intensities
Foot Candles |
Lux |
Area of Operation |
| 5 | ~50 | General construction area lighting |
| 3 | ~30 | General construction areas, concrete placement, excavation and waste areas, access ways, active storage areas, loading platforms, refueling, and field maintenance areas |
| 5 | ~50 | Indoors: warehouses, corridors, hallways, and exit ways |
| 5 | ~50 | Tunnels, shafts, and general underground work areas (Exception: minimum of 10 foot-candles is required at tunnel and shaft heading during drilling, mucking, and scaling; Bureau of Mines approved cap lights shall be acceptable for use in the tunnel heading) |
| 10 | ~100 | General construction plant and shops (e.g., batch plants, screening plants, mechanical and electrical equipment rooms, carpenter shops, rigging lofts and active store rooms, mess halls, and indoor toilets and workrooms) |
| 30 | ~300 | First aid stations, infirmaries, and offices |
Source: OSHA 1926.56
For non-construction areas not covered in Table D-3, OSHA refers to the American National Standard Institute (ANSI) A11.1-1965, R1970, Practice for Industrial Lighting, for recommended values of illumination, updated to ANSI/IES-RP-7-1991. The ANSI standard provides an extensive list of recommended illumination levels for indoor and outdoor areas, job tasks, and specific situations.
OSHA has not published separate illumination standards for general industry but may issue citations for poorly lit non-construction workplaces under the general duty clause. The general duty clause is the OSHA requirement that employers must provide a place of employment which is free from recognized hazards that are causing or are likely to cause death or serious physical harm to employees, regardless of specific regulations. It is recommended that employers maintain minimum illumination intensities for the areas of operation listed in Table D-3 and consider additional task lighting. Emergency exits must be illuminated to a surface level of five FC.
OSHA does not provide a recommended or required set of illumination levels for office workplaces. While brightly lit office spaces are considered to enhance safety and productivity, a bright environment may be an impediment and cause eye problems and fatigue for some tasks (like viewing a computer screen). So, OSHA generally allows the employer to design computer work stations as they see fit with guidance provided by eTools, an OSHA web-based interactive training and assessment tool.
OSHA also regulates electrical safety aspects for lighting. Lighting outlets and switches must be placed in a safe location and away from moving parts and other hazards. Lighting installations must be properly grounded and wired. Temporary lighting cannot exceed 600 volts or be used for over 90 days. Flickering lights may indicate a nearby electrical interference.
Indoor Light Levels
According to European Standard, EN 12464 Light and lighting – Lighting of workplaces – Indoor workplaces, the minimum illuminance is 50 lx for walls and 30 lx for ceilings. In the past, light levels in the range of 100-300 lx were common for normal activities. Today a 500-1,000 lx range is more customary – depending on activity. For precision and detailed work, the light level may even approach 1,500-2,000 lx.
Illumination Assessments
Complaints of poor illumination, glare, high color contrast, or flickering lights indicate that a workplace may be in need of a lighting or illumination assessment. A lighting assessment may be recommended for comfort, productivity, safety, or compliance concerns. The proposed assessment should address a range of concerns; be performed by a qualified person, such as an industrial hygienist or illumination engineer; and include detailed observations by that professional and a photometric survey according to the objectives of the study. A general illumination assessment for compliance will include a series of vertical and horizontal measurements with an illuminance meter and may involve other types of visible light measurements.
Compliance and Consulting Services…from HETI
HETI’s Certified Industrial Hygienists and safety professionals are available to assist clients comply with OSHA’s Illumination Standard, among others. Whether the need is for written programs, training, or workplace exposure assessments, or simply addressing questions on compliance, we are here to help.