Light Fittings & Luminaires | Lighting 101 | Unit 3
By James Wilson
A light fitting or luminaire is the device or apparatus which carries the light source (see Unit Two - Light Sources Explained) and contains the means of connecting the light source to the electricity supply.
At the very simplest, a luminaire can be nothing more than a lamp holder (or light bulb holder) together with a means of attaching it to a wall or ceiling. At the other end of the scale there are strikingly decorative luminaires - chandeliers for example - or complex luminaires which allow the control of the output from the light fittings.
Central pendant light supplemented by a range of other light fittings.
Pendant Light Fittings
Pendant light fittings pre-date electric and gas lighting and the principle of a single centrally suspended light source is to provide light throughout a room. In terms of lighting design (see Unit Five - Basics of Lighting Design), the principle is not altogether sound. It may be difficult to balance effectively the light levels in the centre of the room with the edges. There may be problems in irregularly shaped rooms. And pendant lights can be particularly unsuited to lighting things on walls - pictures, posters, bookcases etc - because the viewer may cast a shadow on the thing being viewed. These problems can be mitigated by having more than a single pendant and additional light from other fittings. Pendant lights remain an important part of lighting design because they are an expected feature and provide a general or ambient level of light in a room. They are also particularly useful over surfaces - tables or kitchen work surfaces for example - for providing both mood and task lighting.
Pendant light fittings above a kitchen island and sink unit
Pendant lights also provide opportunities for adornment or decoration in a room. A bare filament bulb in a lamp holder (see Unit Four - Lamp Holders Explained) can fulfil these purposes and is a style which has enjoyed a recent resurgence. But looking to more decorative options, there are endless choices of lamp shades and adornments for pendant lights. Materials to consider include transparent (glass), translucent (glass, fabric, or polymer) and opaque (metal and other materials). Styles include every design movement, trend and cultural reference: from cubism, industrial to Harry Potter. The key to choosing a pendant light and lamp shade is that it is practical in terms of light output/distribution and enhances/complements the overall aesthetic.
Downlights are recessed into the ceiling and a row or rows of downlights can be highly effective at providing light exactly where it is needed. The predominant light sources in downlight luminaires were halogen spotlights (such as GU4/MR11, GU5.3/MR16, or GU10), but the development of LED technology now means that for most applications LED light sources are more efficient and long-lasting alternatives. Downlights are generally installed in suspended ceilings or a ceiling void and there are various issues which affect their suitability. The void has to be deep enough to house the fitting and the facing surface suitable for fixing. Most downlights run off less than mains voltage and therefore require transformers which can also be installed in the void. Because of the heat produced, the void needs to be suitable: nothing flammable and deep enough to allow heat to dissipate from the downlights and any transformers. In addition to the risk of the fire caused by the downlights, cutting holes in plasterboard - which acts as a fire barrier - can allow fire to spread more easily. Some downlights are fire rated for a period. There are also IP rated downlights for installation in the protected zones in bathrooms.
Wall lights in a kitchen providing task lighting above the work surface and ambient lighting for the room
Both halogen and LED light sources offer a range of light outputs, beam angles (the size of the cone produced by the light source), colour temperatures and dimming options. Because the light sources in downlights can be very bright, there are techniques for reducing glare - being able to see the light source directly. These include recessing the light source in the body of the downlight, baffles and spreader lenses. There are also various methods which allow for the light source to be directed towards a particular object or task including pivots/gimbals and 'eyeball' type fittings. A final point about downlights is that because they produce cones of light, it's important to get the spacing right. Overlapping or intersecting the circles may be required to avoid dark/dim patches. And the distance of the first row away from a wall should generally be half the spacing between rows to ensure appropriate light levels.
Wall and Ceiling Lights
Wall and ceiling lights are light fittings or luminaires fixed to walls and ceilings. They encompass a huge range of designs and styles and offer a variety of light sources. A wall or ceiling mounted spotlight may project all its light into the room or space and provide no illumination on the mounting surface. In contrast, a wall washing light fitting might provide very little illumination of the room or space and light only the surface on which it is mounted.
Wall lights used as an alternative to bedside table lights.
Wiring and control are important with wall and ceiling lights. To wire the fittings, there will need to be a wall or ceiling void to house the cabling or it will need to be 'chased' into the surface - much easier with blockwork than brick and stone. Installation of wall and ceiling lights is comparatively straightforward with new builds and major refurbishment, but at the very least is likely to require major redecoration of the room or space. The positioning of the wiring - vertical and horizontal position - needs to be right at first fix to avoid problems later. An alternative is the use of galvanised conduit to surface mount wiring, but this is limited to rooms or spaces where the conduit is in keeping with the overall aesthetic. While some wall and ceiling lights are controlled at the fittings, most are controlled at the main wall switch with the pendant light or lights in a room. The starting point to choosing wall and ceiling light fittings is to work out their function or functions. While most light fittings will fulfil a number of lighting design purposes (see Unit Five - Basics of Lighting Design), whether that be supplementing general or ambient lighting from pendant light fittings, task lighting for activities such as reading, or lighting architectural or artistic features. Adjustable wall and ceiling lights offer greater flexibility and there are IP rated light fittings suitable for installation in bathrooms or areas where there is a risk of water splashing.
Floor and Table Lights
The key advantage of floor and table lights (portable luminaires is the technical term) is that the installation costs are low (compared to pendant, wall and ceiling lights) and they are versatile - it should be easy to choose a fitting which provides the right light in the right place. Floor and table lights are generally powered by a wall socket or floor socket, which imposes some limits. The socket must be accessible and reasonably close to the floor or table light and, even then, the supply cable may create a trip hazard. Installing additional sockets or moving the position of an existing socket raises the same issues as the installation of wall lights. Portable luminaires are generally controlled by a cord switch, floor switch or switch on the body of the fitting. They are particularly suitable for task lighting - desk and table lights - and low-level mood lighting in living rooms - standard lights.
An ingress protection (IP) rated bulkhead style wall light.
Generally, table and floor lights have a convention lamp holder (see Unit 4 - Lamp Holders Explained) and can be used with a range of light sources. This allows the choice of a light source based on the purpose of the light fitting. Perhaps a low energy LED with a warm colour temperature and low lumen output for ambient and mood lighting in a living room. For reading and other close activities, the light source should be brighter and closer to daylight in colour temperature. There are, of course, a huge range of floor and table lights in a huge range of styles, designs and materials.
While there are a huge range of options when it comes to lighting fittings or luminaires, they are all covered by the same British and European standard: BS EN 60598. Before you buy or install a luminaire, you should check the packaging and luminaire itself to ensure it complies with BS EN 60598. The next unit of Lighting 101 - Unit 4 Lamp Holders Explained - looks at the various lamp holder options commonly available with pendant, wall and ceiling lights.