It’s very important to measure light and lux levels in the workplace; bad lighting can be hugely detrimental to your business and jeopardise your safety. Low light (or low Lux levels) may cause fatigue, muscle strain, and costly mistakes in industry, particularly if an employee or colleague is exposed to insufficient lighting over long periods of time. It’s the same for excessive light (or Lux) levels. Glare, and reflected light can distract an individual and impair his or her vision, which is particularly dangerous when a job requires the worker’s full attention, such as working with machinery or hazardous chemicals.
Appropriate lighting should be ensured at all times through testing and regular maintenance. Under the Health and Safety at Work Act of 1974, an employer has a duty to ensure the health and safety of employees. The Act includes a duty to provide lighting to ensure that work can be done safely, and that employees health or eyesight are not jeopardised. Regulation no.8 of the Workplace Regulations Act 1992 states that employers must ensure that:
Every workplace has suitable and sufficient lighting.
This should be natural light, so far as is reasonably practicable.
Suitable and sufficient emergency lighting shall be provided where needed.
To test, and maintain a required lighting level, it’s standard industry practise to use a light level meter. These instruments will typically provide a luminance reading based on either Lux or Foot-Candles. Lux (Lux) is a unit of illumination of one square metre, which is one metre away from a uniform light source. It is also a European standard of measurement. Foot-Candles (FC) is a unit of illumination of one square foot, which is one foot away from a uniform light source. It is a U.S measurement standard.
1 Lux = 0.0929 FC, 1 FC – 10.76 Lux
The amount of light (or Lux) required to suit your workplace obviously depends on the type of work being done, but the list below gives an indication of the light (or Lux levels) required for different kinds of working environments.
Storage Area / Plant Room (minimal movement of people): 150 to 200 Lux
Construction Areas and Loading Bays (minimal perception of detail): 300 to 500 Lux
Factories and Kitchens (higher perception of detail): 500 to 750 Lux
Inspection, Welding and Machinery (demanding work): 750 to 1000 Lux
Electronics and Textile Production (repetitive work): 1000 to 1500 Lux
Technical Offices (accurate detail): 1500 to 3000 Lux
Jewellers and Goldsmiths (precision detail): 3000 + Lux
Interior light (Lux) levels are much lower than outdoor natural light (Lux) levels. Some typical light (Lux) levels are:
Very Bright Summer Day: Up to 100,000 Lux
Overcast Summer Day: 30,000 to 40,000 Lux
Floodlit Football Match: 700 to 16,000 Lux
Shady Room In Daylight: 250 to 300 Lux
Night Light On A Building: 60 Lux
Night-Time Urban Street: 10 Lux
Night-Time Car Park: 1 Lux
When you’re choosing a light meter, it’s important to understand its associated Lux (or FC) measurement range, resolution, accuracy, and the maintenance required to achieve repeatable measurements. You’ll also need to consider the environment in which the light meter is used. Consider the lists above, taking measurements outdoors will require a much higher Lux (or FC) measurement range, and in a professional environment, the accuracy of your reading will ultimately affect the credibility of your future measurements, and organisation as a whole.
So, It’s also a good idea to have your light meter calibrated before taking a measurement. In today’s market, more light meters are used without firstly being checked for traceable accuracy, or suitability of purpose, yet the accuracy and suitability of your light meter to its intended application could be the difference between passing and failing a health and safety audit, wasting a whole industrial process, or being correct the first time.
Also, if your company is ISO accredited, then having all instruments used as a controlling element calibrated on a regular basis is a mandatory part of the auditable procedure.
Taking a reading is relatively straight forward, simply expose the light meter sensor to your desired environment, and log the reading displayed on the display. If you’d like to submit regular readings to management, auditors, or work colleagues, you may like to consider a data logging light meter. These instruments allow continuous Lux (or FC) measurements to be displayed in real-time, or downloaded and stored to PCs or Laptop computers. The recorded measurements can then be attached to emails or reports, and is great for traceability in critical environments.
If you can choose the light meter best suited to your intended application, AND provide traceable instrument calibration to an auditor, you can always be assured of your measurement’s creditability. If you’re unsure of a light meter’s suitability, always consult the help of a professional body.