Let there be light

All workplaces need to be correctly lit to allow staff to function safely and efficiently and the laboratory environment is no exception to this. Barry Hill highlights some of the issues involved

LABORATORIES layouts are like fingerprints, there are never two exactly the same and this is why it is impossible to come up with a ‘one size fits all’ lighting system to illuminate them.
Various factors such as the architecture, the amount of floor space involved, ceiling height, the natural light available and the type of activities performed within them all combine to ensure that each laboratory has its own, very unique, individual environment. Its surprising however that in many laboratories today both old and new, the lighting systems are often unsuitable, outdated, no longer fit for purpose and in some cases actually harmful to the eyesight of the staff working within them. Good laboratory lighting design must always consider the ‘three E’s’: energy, ergonomics, and efficiency. Questions to be asked therefore in implementing an ideal laboratory lighting system are: Is the design energy-efficient? Does the lighting promote a healthy, comfortable, and productive work environment for laboratory staff and finally, is the lighting system cost effective?
To create an effective and comfortable laboratory lighting scheme  there are a variety of options that need to be carefully explored, each of which can provide a good workplace environment if properly designed and installed. Historically, ‘direct lighting’ systems incorporating fluorescent lights have been the laboratory standard, providing high quality illumination with a downward distribution. Fluorescent light fixtures are energy-efficient, relatively inexpensive, and easy to control plus the linear design of fluorescent lamps tends to match the linear nature of most typical laboratory benches and work areas, fixtures can be either be recessed or surface-mounted to the ceiling. By positioning the lights in continuous parallel rows aligned with laboratory bench, correct and efficient illumination levels can provided to the work surfaces with the minimum shadows and good uniformity. ‘Bi-directional lighting’ systems however are slightly more expensive to install but are the most energy efficient and operate by distributing light in both an upward and downward pattern. To achieve this light fixtures are need to be suspended 12" to 18" below the ceiling and located in continuous rows above the lab bench. Finally ‘indirect lighting’ systems distribute light towards the ceiling and create a more ambient illumination from the reflected ceiling light. Indirect lighting also provides greater visibility at lower lighting levels than direct lighting. To achieve this effect, fixtures are suspended 18" to 24" below the ceiling in continuous rows between laboratory benches which then provides uniform shadow-free illumination on all work surfaces with no glare. These systems are typically less energy efficient than other options; however, the quality of light creates better visibility and can allow reductions in illumination levels. Indirect systems are also the least expensive in terms of construction costs be-cause they use fewer fixtures.
There are various legislative issues also to be considered when choosing a lighting system for the laboratory.  All Employers have a general duty under section 2 of the Health and Safety at Work  Act 1974 to ensure, so far as is reasonably practicable, the health, safety and welfare of their employees at work. In terms of lighting requirements the Health and Safety Executive or HSE recommend that lighting should be sufficient to enable people to work and move about safely. If necessary, local lighting should be provided at individual workstations and at places of particular risk such as crossing points on traffic routes. Lighting and light fittings should not create any hazard and automatic emergency lighting, powered by an independent source, and should be provided where sudden loss of light would create a risk.

Questions that employers should consider therefore are: Why is good lighting at work important? What are the costs of poor lighting to business and What are the risks from inadequate lighting in the workplace? There are also minimum lighting recommendations that much be achieved to avoid visual fatigue, eyestrain and unnecessary glare. For older laboratories in particular, the changing nature of the work involved is an important factor, many of these laboratories now have numerous VDU screens located throughout the building, but yet the lighting systems above them are often dated from the pre-computer era and no longer suitable for the high level of keyboard activity being deployed below. Reflected glare on computer monitors can make VDU screens difficult or impossible to read, and so recessed louvered fixtures can be a good choice for these situations since they reflect light downward, thereby keeping glare off computer screens. Additionally, lights should be changed periodically to prevent a  gradual loss of light intensity occurring. Finally, laboratory staff should have access to regular eye testing if they request it.

Good laboratory lighting should provide adequate lighting levels without creating harmful, reflected glare, which can not only be annoying, distracting and stressful, but can lead to possible laboratory errors occurring. Light sources, lighting fixtures, and their components therefore must be carefully selected to provide the optimal quantity and quality of light. Energy-effective lighting design incorporating appropriate lighting design principles should be used to create a good visual environment while minimising energy use. Other features such as under-shelf lighting can help direct light where it is needed to create a uniformly illuminated work area which minimises glare and shadows. White benches and shelves can also greatly contribute to laboratory lighting levels and as much natural light as possible should be incorporated to create a healthier environment and to help distribute the available light throughout the entire laboratory. Desks and workstations should therefore be ideally be placed perpendicular to the window wall to allow maximum daylight penetration. Lighting the laboratory at night is another factor to be considered, some newer laboratory builds incorporate automatic controls to dim or turn the lights off at night to save energy.

So with the many types of lighting systems and innovative designs now available to illuminate the laboratory which balance energy, ergonomics, comfort and efficiency there can be no excuse for laboratory staff to have to endure poor visibility at the bench any longer. If so however, the HSE would no doubt take a dim view of that.