Lighting
Most houses are built with a minimum of thought given to the proper provision of lighting and, often rooms have just one central ceiling light fitting. A more sensible arrangement – for most rooms in the house – is to provide at least two sorts of light – general light for seeing across and around the room and specific light directed at particular places or provided to illuminate particular tasks. You can also have effects light for decoration – to light pictures, curtains or prized objects, for example.
Lamps and fittings
All lights consist of two parts – the bulb or tube (more properly called the lamp) and the fitting into which the lamp goes. They both have an effect on how much light is given out and the sort of light given out. The light given out can be directional – a well- defined (and usually powerful) beam – or diffusing – spreading light over a wide area, sometimes in all directions, but often more in one direction than any other. Lamps and fittings are often classified as directional or diffusing.
How much light?
Illuminating engineers describe light levels in lux (the amount of light – in lumens – falling on a square metre of surface). The more lux, the higher the light level. The general light level recommended for most rooms (living rooms, studies, bedrooms and so on) is about 50 lux; as a general guide, in order to achieve this you need to allow at least 16W of a GLS lamp for each square metre of surface to be lit.
Ordinary pendant ceiling lights can provide some or all of your general light. How many you need depends on how reflective the room’s decorations are and how transparent the shades are. To provide 50 lux in a living room about 5m by 4m, you’d need a total of around 300W of tungstenlight in two or more fittings.
If you use directional fittings aimed at walls and ceilings, you’ll need quite a high wattage – up to four times the amount you need for pendant ceiling fittings – especially if the walls are decorated in dark colours. Fittings with large beam angles will help to give an even light – so PAR 38 floods, ISL lamps, or GLS lamps with wide reflectors would be best. You could use fluorescent tubes in this way too. Concealed fluorescent tubes behind cornices or pelmets, for instance, give a good flood of even light.
Specific light is necessary for watching TV, operating hi-fl, reading in armchairs, working at a desk and for close work like sewing or darning.
For watching TV, the position of the light is more important than how powerful it is – you need only enough light to prevent the picture from being too glaring (which is tiring on the eyes) – you should position it to light the area around the screen without producing any reflections in it.
The recommended level for casual reading and things like operating hi-fl is 150 lux; for prolonged reading and working at a desk it is 300 lux.
These levels can be achieved with standard or table lamps with ordinary shades using 100W bulbs provided they’re close enough to the work (and the shade can take the load). But it’s probably best to use directional fittings, spotlights or desk-type lamps.
The amount of light you need on close work depends a lot on how much the work reflects light – needlework on dark material may need twice as much as light-coloured material.
A separate fitting isn’t necessary for each of these jobs, if you use movable fittings and position them carefully you can use them to light different areas. If you use adjustable directional fittings for your general lighting, you might be able to re-direct them for occasional specific lighting.
LAMPS
There are five main kinds of lamp used in the home: four are filament lamps, the fifth is fluorescent. The lamps are described overleaf, the main things you need to know are:
• the type of cap – most are the familiar bayonet type, but many now have Edison screw caps. The cap affects the sorts of fitting in which you can use a lamp • how long it will last. This really depends on how often you switch the light on and off. Lamp life is a guide – an average of tests on many samples
• the sizes available. Lamps are sold in wattages as a measure of the power they consume (a 100W lamp uses 1 unit of electricity in 10 hours)
• the amount of light. Wattages can be used to indicate light levels, but there’s no simple formula as the amount of light per watt also depends on the type of lamp and the fitting. The amount of light actually arriving at a surface varies with the distance of that surface from the light and will vary depending on whether the surface itself is centre beam or off beam. Light levels at 2m are a guide.
Types of lamp
General lighting service (GLS)
Ordinaryfilament light bulbscan be used in all sorts offittings.
Lamplife 1,000 hours (long life last 2000h or more, but cost more)
Fluorescent tube F3
Lampsare mostlytubularand come in a numberof lengths and two main diameters25mm and 38mm, But there are now also special (expensive) fluorescent bulbs which will fit infittingswhichtake GLS lamps. Light is produced bythe electrical discharge in the tube, and by the fluorescent coating on the inside. Different coatings on thetube produce differentsortsofwhitelight. Mustbe used in special fitting.
Crown -silvered ( CS)
Looks much likeanordinary light bulb, but front issilvered so that all the light is projected back. Used with fittings having a special
Internally-silvered lamp (ISL)
Available in ‘flood’ or’spot’ versions, although the spot beam is considerably wider
Parabolic aluminised reflector (PAR 38)
Bulb is pressed from toughened glass which can withstand thermal shock—sudden cooling dueto rain for instance. Can be used outdoors in waterproof lam pholders. Hasan
Wattages 25W.40W,60W,100W,1 50W Lightlevelsat2m Depend on how light is reflected or diffused. With reflector fittings producing narrow beams ofl 2 to 25,a l00Wlampcould give 300tol,700 lux. With fittings that don’t reflect light, levels might be as lowas 30 lux. A60Wlamp gives about half theoutput, a40W lamp about a quarter.
Lamplife About 7,500hoursforlamps 1 200mmormore long
Wattages Generally depends on length1200mm is 40W (or 36W in energy-saving version)
Lightlevelsat2m Much oflightwillbe reflected, so depends on size of room, and how reflective ceilingsandwallsare. A
1 200mm4oWwarmwhitetubeshouldgive about50lux ma room 4m x 3m. Mostother tubes have roughly the same efficiency (a 65Woneproducesabout90lux) buta
600mm 40W tube produces only about 34 lux De-luxe warm whitewillgiveabouttwothirdsof these levels but gives a warmer light with bettercolour rendering closerto a G [S lamp
parabolic reflector to reflect lightforward again in a narrow beam. Very little glarefrom side. Coloured reflectors available
Lamplife About 1 000 hours
Wattages Usually 60W, 100W. Also 40W miniature version
Lightlevelsat2m Dependmainlyon reflector used: 1 OoWtypically between 600 lux and 2,000 lux, 60Wabouthalfthatof 100W
than a CS spot beam. Has an internal
reflective coating, solightcomes out only at thefront. Long neck;frontcanbecoloured Lamplife About 1 000 hours
Wattages Usually 75W,100W,also available in 60Wand in miniature40W versions.
internal reflecting coating solightcomesout onlyatthefront. Available in both spotand flood versions, High-wattage PAR lamps are also available—eg PAR 56 (300W)—which have an elliptical beamand producevery high lighting levels,
Lamplife Aboutl .500hours
Wattages 10OWandl5OW,spotandflood. Can becoloured
Lightlevelsat2m l00Wspotgivesabout 1,000 lux, 1 50W spot about 1,800 lux: 100W flood gives 400lux, 1 b0W about 700lux.
In living rooms you’ve avery wide choice of light fittings and the ways you can arrange them are also wide ranging.
I Pendant lighting Pendant shades hide the lamp and spread the light.
They’re good for general diffused illumination, but can be lacking in
interest and decorative quality. Long pendants can provide a semi-directional light in a corner or over a table. Single pendants can be on a rise-and-fall suspension. Pendants can be grouped from a multi-outlet ceiling rose — a good arrangement for a stairwell where the lamps can be hung at different heights.
Down lighting Downlighters mounted in matching pairs give a directional light which can be a wide or narrow beam. A variety of different types and shapes including fully-recessed, partially- recessed and ceiling-mounted (concealed) fittings are available. They take GLS or reflector lamps. Eyeball spotlights are among the most versatile as the angle of light can be varied (though you have to climb up to alter them).
3 Spotlighting Spotlight fittings with reflector lamps mounted on or in the ceiling give directional light. The angle of spot and choice of beam —wide, narrow or shaped —can alter the appearance of objects. Care is needed in angling to avoid casting glare into the eyes.
4 Diffused wall lighting A fluorescent lamp and fitting mounted behind a pelmet or baffle give an even spread of wall light. Wall-mounted lights are best shaded from the eyes and should use low-powered lamps.
5 Local lighting Standard and table lamps provide good local light—for reading, for instance. The light can be diffused or directional. For a table lamp, the height to the bottom of the shade should be about 300mm ;forstandard lamps 1 -2m. If the light source is visible use pearl rather than clear lamps.
6 Picture lights Anysortof directional light can be used for pictures Linear filament lamps can be used in suitable fittings for lighting pictures. Make sure you cannot look directly at the bulb from a standing or sitting position and that there’s no glare off the glass.
the wiring may look more comp licated, but the connections are essentiallythe same as in arose, with all the live (red) conductors too ne terminal, allthe neutrals (blacks) to another and the earths (often bare but preferably insulated with green/ye llowsheathing) to a third. The fourth term inal usuallycontains one blackand one red insulated conductor, these being the return from the switch and the supply to the rose respectively. (The return fromtheswitch isliveand should be marked with red insulation.)
The newjunction box iswired sothatthe three conductors of the incoming circuit cable each goto their respective term inals. The cable is sized to match the rest of the circuit—usually 1 mm’. The cable tothe switch has its red conductor connected to the I iveterminal ‘its black conductor sleeved with red and connected to the fourth terminal. The cableto the lightfitting has its red conductor connected tothefourth terminal and its black conductortothe neutral. All earth conductors are connected to earth.
Conetion neat an e a n The ligh
Some kindsof bedroom lighting Bedrooms need special treatment. Consider:
Sn • two-way switching at the door and
lights
7 Shelf and cupboard lighting bed for the main light fitting
ould Miniature fluorescent or linear filament • lighting for reading – i 50 lux is
lamps can be fitted to the back edge of recommended. Lamps can be placed at
a cupboard or below or above shelves, the side of the bed as standards
ible anywhere in fact where the lamp can be supporting spot lamps, orwall-fixed in
concealed and the light will be useful. the centre, orovereach pillow. Ordinary pendant ceiling lights (orwall lights)
mp,
8 Track lighting A metal or plastic over the bed with 100W bulbs can give
e channel carrying concealed electrical use high-wattage PAR lamps in special you enough light provided they’re close
d conductor allows lights with special fittings. They should be dimmer enough and have fairly transparent
ble adaptors to be clipped along its length. controlled and fixed high on the ceiling shades. Choose a fitting with a very sharp
Lengths of track can be clipped together. as they give off a lot of heat. beam for reading without disturbing a
Although normally ceiling-mounted, the partner
track can also befitted on a wall. It can
10 Up lighting An interesting effect • dressing table mirrors need lights
ures.’ be connected via a ceiling rose or directly can be achieved by installing a lamp on either side at head height when sitting
to the lighting cable (it isn’t suitable for the floor-there are cylindrical fittings for down. The light should shine on you–
–
bathrooms). this purpose. A lamp could be installed not on the mirror- and it’s helpful if it
3t the in a recess in the floor, but then it must doesn’t shine directly in you reyes. Don’t
on
9 Flood lighting Although they’re be sealed with a strong, well-supported use bare bulbs -they can explode in your
normally used outdoors, large rooms can cover-a glass brick for instance, face.
