Three ways to light a laboratory

Laboratories aren’t just in schools. You might also think of high-tech drug companies, but there are many more in all sorts of places. Government research and trading standards bodies have them, as do supermarket chains and food producers. Of course, the chemical and plastics industries are full of them. And we shouldn’t forget our own lighting industry.

As a consequence, not all laboratories are lit in the same way. As always with lighting design, you first need to ask what people do in the location. What are their specific requirements?

In a laboratory, you might want to ask how important colour rendering is and whether the lighting should reveal imperfections on surfaces or degrees of cloudiness in liquids. Do staff need to see fine divisions on a thermometer or pipette? Should the luminaires be totally sealed and easy to clean? Are there any corrosive fumes?

I went to a laboratory where the staff wore full personal protective equipment but the plastic diffusers on the luminaires had crazed and degraded.

Obviously, you should also consider the more general aspects of lighting such as glare, horizontal and semi-cylindrical illuminance. Quite often, the staff will do office-type tasks in the same space. There’s hardly a lab in the land that doesn’t have computer screens.

For general guidance, you should consult EN 12464 and the Code for Lighting. It is almost certain that your client will have their own particular requirements.

Our laboratory is about 6 x 12m with a ceiling height of 3.5m. The eagle-eyed will notice that the luminaire in the fume cupboard is the same in all three options.

This is a fairly conventional scheme with a surface-mounted linear luminaire. This particular one is a high-end LED, but T5 would be almost as efficient and maybe quite a bit cheaper. The ‘diffuser’ is one of the new generation microprismatics. In fact, they have been around for a while, and are lot more efficient, in terms of light output ratio, than a conventional diffuser. You should look out for them.

The alignment of the luminaires is parallel to the line of sight, so the scheme is less glaring than a transverse layout where you see them sideways on.

We have chosen a luminaire that has smooth outer surfaces and can easily be wiped clean. However, it is not highly IP rated.

 

Tech spec

Luminaires Surface-mounted linear LED

Optical control Opal and microprismatic

Arrangement Three rows of four

Average horizontal illuminance on lab worktop 460 lx

Electrical load 7W/m2

Pros Economical and efficient

Cons Not so good with a high ceiling

The luminaire here is semi-recessed and replaces a 600 x 600mm ceiling tile. There is a drop-down section that houses the 24W T5 lamps. These direct the light directly downwards through louvres and a perforated screen and also indirectly from the curved upper face.

The configuration of direct/indirect lighting and various internal reflecting surfaces cuts the overall efficiency of the scheme compared with the other options. However, the effect is of a very low-glare luminaire that gives good illumination on horizontal and vertical surfaces.

It may be harder to clean, but there is little accumulation of dust in a laboratory so it may not be a significant issue.

 

Tech spec 

Luminaires Semi-recessed with T5

Optical control Indirect reflector and louvres

Arrangement Three rows of five

Average horizontal illuminance on lab worktop 358 lx

Electrical load 11W/m2 

Pros Low glare

Cons Least efficient

This layout and variations of it are quite common. In essence, the luminaires are built in to the structure of the laboratory shelving. They usually use direct/indirect luminaires to minimise the depth.

These schemes need extra care because you must consider the height of the luminaire and the viewing lines in relation to the personnel, who may be standing for a large proportion of the time.

The big advantage is that the whole scheme could almost be considered local lighting. There is plenty of light just where you need it. If you can avoid any chance of glare, this can be a really good solution.

This layout and variations of it are quite common. In essence, the luminaires are built in to the structure of the laboratory shelving. They usually use direct/indirect luminaires to minimise the depth.

These schemes need extra care because you must consider the height of the luminaire and the viewing lines in relation to the personnel, who may be standing for a large proportion of the time.

The big advantage is that the whole scheme could almost be considered local lighting. There is plenty of light just where you need it. If you can avoid any chance of glare, this can be a really good solution.

 

Tech spec 

Luminaires Shelf mounted

Optical control Internal reflector and diffuser

Arrangement On the edge of each shelf, as shown

Average horizontal illuminance on lab worktop 442 lx. 

Electrical load 7W/m2 

Pros Unobtrusive and neat

Cons Take care to avoid glare

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