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Lighting - A Guide

Lightbulb types

Fluorescent light sources
(Contain gases in a tube but have no filament)
These have been around for many years now and are better known as the long white tubes commonly seen on utility ceilings. Recent technology has reduced the size and improved the efficiency. Many different shapes and power options are available.

The benefits are low power consumption (around 20% of a normal light bulb) and long life (up to 8000 hours). They are ideal for lights which need to be kept on for a long time. Many people assume that fluorescent light is 'cold' but 'warm white' lamps are available which improve the colour.

Incadescent light sources
(conventional filament bulbs)
These are the conventional bulbs which we all recognise and their advantage is the colour of light that they emit. Colours of objects are generally more accurate with this type of light bulb and they impart a warm felling to a room.

The disadvantage is that they are inneficient by modern standards and have a relatively short life (around 1000 hours).

Incadescent lamps come in a variety of shapes and sizes and have a number of different fittings:

• Bayonet cap (BC)
• Small bayonet cap (SBC)
• Edison screw (ES or E27)
• Small Edison screw (SES or E14)

The Edison screw types are becoming more popular in the UK.Several different coatings are also availablewith the following properties:

Pearl is an all over frosting which diffuses the light and is best used in a light fitting with shades.
Clear bulbs are more attractive when in fittings wher the bulb is visible or a sparkle is required such as crystal chandeliers.
Reflector bulbs have a silverd surface to direct the light in a certain direction and are usually intended for directional fittings such as spot lights.

 

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Halogen light sources
(filament bulbs containing halogen gas)
Halogen bulbs produce a very attractive light which closely resembles sunlight. They are more efficient than incadescent bulbs using only half the energy to produce the same light output and last twice as long. Generally they are small lamps which generate alot of heat so they can only be used in light fittings designed to cope with high temperatures.

There are two main types of halogen light available on the domestic market:

Low voltage These lamps operate on 12v which means a transformer has to be fitted either in the light fitting itself or remotely. The advantages of the lower power are that the safer voltage enables the manufacturers to produce interesting and slim designs without the danger from higher voltages. Transformers can be either electronic or 'wire wound'. The newer electronic transformers are more energy efficient and smaller. Electronic transformers can be damaged by voltage spikes in the mains supply caused by fluorescent lights, older motors, fridges, lift shaft motors etc. If persistant problems occur the use of mains voltage lighting is recommended.

Mains voltage This relatively new breed of lamps offers the light colour advantage of halogen without the need to house a transformer. The reflector type bulbs are known as GU10 or GZ10 and the latest small envelope non-reflector halogens are known as G9.

Dimmers
Most tungsten and halogen light fixtures are dimmable but only certain types of fluorescent can be dimmed. When installing a dimmer you should check on the compatibility of the fitting with the dimming device and that the dimmer has sufficient capacity to control the load on the circuit.

General tips on lighting your home

Many people spend a great deal of money decorating and furnishing their homes to create an atomosphere only to find that something is missing. Good lighting will compliment and complete the effect that you are looking for but remember that bright lighting is not always good lighting.

A light source creates a pool of light but there is a second effect which cannot be reproduced in the shop where you buy your lights. Consider where you are to put the light and the surfaces under and around it. What effect will the reflected light have?

Avoid hard contrasts which can be tiring to the eyes and where possible try to combine different types of lighting in the same room. Direct lighting for reading or working, pools of light to highlight features such as paintings or objects and washes of light on walls all help to add atmosphere to a room whilst remaining functional. If a room has to perform several different functions, consider installing a dimmer. This will allow a higher light level for working or reading and a lower light level for relaxation. This can prove useful too for older eyes which need more light.

Colour is most important, incadescent bulbs help create a cosy atmosphere in living areas while fluorescent lamps give a cooler, more efficient light for utility rooms. A room painted in a dark colour will need more light as much of it will be absorbed, whilst lighter colours reflect light. You can add colour to a room by illuminating a coloured surface.

Avoid glare by placing lights at a height which prevents the eye from seeing the bulb directly. Pendants should not be hung so high that the bulb is clearly visible underneath. Take care that lights placed over reflective surfaces such as glass tables have a diffuser in them.

How much light?

Determining the correct light levels for a home environment is a very complicated subject and depends on a dgree on the individuals perception and requirements. The formula below, however, can be used as a rule of thumb.

Measure the room size in squre metres and multiply this by 25 (for incandescent lamps) 15 (for halogen lamps) or 19 (if using compact fluorescent lamps). This figure will give you the total watts required to light the room.

Example 1: a room 5m x 5m has an area of 25sq metres. If we are to use conventional incandescant lamps multiply this by 25 giving a total wattege of 625 watts. This can be made up as required, for example as follows:

2 x 75W table lamps =150W
2 x 3 light ceiling lights
each with 40W bulbs =240W
2 x double wall lights
each with 40W lights =160W
2 x single wall lights
each with 40W bulbs = 80W
TOTAL 630W

Example 2: a kitchen 3m x 6m = 18 square metres. If we intend to use low voltage halogen dichroic lamps then we multiply by 15 to arrive 270 watts required in total. This can be made up as follows:

1 x 3 light halogen bar fitting adjustable heads each with 50W lamps =150W
6 x downlighters mounted in the ceiling each with 20W dichroic lamps =120W
TOTAL 270W

Please note that this formula is a guide only and some people prefer more light, others less. A useful measure is to over estimate by 10-15% and install a dimmer to give you more control. If in doubt seek professional advice.

Room by Room

Different rooms have different functions, accordingly each room will have a different light requirement. The following guide will help you decide which light sources you need for each room in your house...

Living Room

Avoid using one central light which will create hard shadows and possibly glare. Instead aim to use plenty of different light sources to create pools light, this will give a more interesting effect. Lets start with where you sit. An adjustable reading light beside or behind your chair which can be switched whilst seated will prove invaluable. If it can be adjusted for height even better.
Two or three table lamps placed around the perimeter on tables, shelves or furniture will give the room a more spacious feeling as the light radiates inwards. These small pools of light also create interest.
Illuminate bookcases, pictures or objects of interest with picture lights or halogen spot lights. This indirect lighting of a different colour will add contrast.
Wall lights and pendants on a dimmer switch can raise the level of illumination in the room without needing to adjust any of the other light sources but beware of glare if they are mounted too high. Indirect light from wall washers (light fittings designed to light the wall and ceiling often made in ceramic or plaster) will create dramatic effects. Remember that the light given rom wall washers will be coloured by the surfaces on which they are mounted.
Floor lamps come in many guises and can be very effective at adding general illumination to a dark area where it is not easy to fit wall light, ceiling lights or table lamps. A floor uplighter gives a bright wash on the ceiling. Some are fitted with dimmers and others have a second flexible arm for reading.

Kitchen

We spend most of our time in the kitchen and it has multiple functions, many of which require care to avoid accidents. A higher level of illumination is required here. Fluorescent tubes under wall mounted units cast an efficient light over work surfaces and prevent shadows. They also ensure you are not blocking out the very light in which you need to work.
A central light is also important in a kitchen to provide a general level of illumination and, if you have the space, the use of halogen spot lights mounted on the wall will help you add accent.
If you have glass fronted display cabinets in your kitchen the use of small halogen lights specifically designed for the purpose will add interest.
If your ceiling is low or you want to avoid a central light, consider the use of a number of downlights which create a glare free and pleasing effect whilst remaining functional.

Dining Room

The main light source here will be over the dining table. The use of a dimmer will allow the table to be used for such jobs as sewing and yet give a low mood light for dining. Don't hang a pendant so low that your diners have to peer round it, about 60cm above the table is about right. Better still fit a rise and fall pendant. If you like to dine by candle light, make sure the heat and smoke are far enough away from the light fitting. If you have a glass dining table, make sure the light i fitted with a diffuser so that your diners are not looking at a reflection of the light bulb. Long tables can be very effectively lit with a longer light fitting suspended on two wires.

Bathroom

Great care needs to be taken when choosing bathroom lighting as te regulations are strict concerning the type of light you can use. The bathroom mirror deserves some special attention and a diffused glass light either side will give a good general illumination where it is needed. The alternative is a halogen downlight from the ceiling or fluorescent strip light over the mirror. The latest generation of mirrors incorporate lights into the mirrors themselves with sections of the reflective surface removed and lights fitted behind them. This is a very effective way of generating an even light and improving safety.
For general illumination in the rest of the bathroom either use downlights for their refreshing halogen colour or a high output flush ceiling fitting to suit the decor. Portable lights are not permitted in a bathroom so for mood lighting use ceiling mounted directional spotlights aimed away from the bath and at interesting features. Lights designed specifically for showers are available and must be carefully fitted according to instructions.

Bedroom

This is an area so often neglected. Consider the number of functions required of a bedroom. For dressing you may need a general illumination or, if your partner has to rise at a different time, do you need a lower level of pool of light which won't disturb them? A well positioned downlighter will help here. Many people read in bed and with a double room, it is useful to have bedside lights which are individually switched. Adjustable reading lamps are ideal if you want to read while your partner sleeps. For convenience and safety you should aim to have all of the bedroom lights controlled from the bed.
Dressing tables used for make-up will need more specific lighting and the use of two slender table lamps either side of a mirror gives a good working light without glare and will add to the cosy effect of the room. Try to create pools of light to reduce any hard contrasts. Adding a table lamp or illuminating pictures will be very effective.

Study

A general background illumination is important to avoid the hard contrast if only a desk lamp is used. Indirect wall washers or a floor lamp will do nicely. For the desk lamp look for one which is adjustable for height and will reach over the area where you are working. It is most important to avoid working in shadows. If you have a computer try and light the wall behind it to avoid tiring your eyes when looking at the screen. Make sure the lights in the room do not reflect off the screen into your eyes.

Children's Room

A good central ceiling light is useful to provide a general illumination and a bedside or wall mounted reading lamp is recommended. Night lights for children's rooms give peace of mind and cost very little to run. Older children will want to have fun lighting and there are many effective novelty lights but always be safety conscious and choose lights which are suitable for the age of the child.

Bathroom Zones

What is bathroom zoning? Put simply, the bathroom area has been divided up into 'zones' or areas which are classified using the numbers 0-3. Light fittings are then assigned an IP rating which indicates how much protection they provide against ingress of water and other particles. Each zone has a minimum IP requirement that must be met if a fitting is to be installed in this area.

ZONE 0 Inside the bath or shower. Any fittings used here must be SELV (max 12v) and have a minimum rating of IPX7 (protected against immersion in water) ZONE 1 Above the bath or shower to a height of 2.25m. A minimum rating of IPX4 is required. If there is a likelyhood of water jets being used for cleaning the IPrating should be increased to IPX5. ZONE 2 The area stretching to 0.6m outside the bath or shower and above the bath or shower if over 2.25m. An IP rating of at least IPX4 is required. If there is a likelyhood of water jets being used for cleaning the IPrating should be increased to IPX5. ZONE 3 Anywhere outside zones 0,1 & 2. Where water jets are not used for cleaning purposes, the general rules of BS7671. If there is a likelyhood of water jets being used for cleaning the IPrating should be increased to IPX5.

IP Ratings Explained

IP stands for 'Ingress Protection'.

First Digit - Protection against ingress of foreign bodies

e.g. tools, dust, fingers, etc.

Second Digit - Protection against ingress of liquids.

e.g. IP44 is protection against solid objects greater than
1mm IP4X and waters sprayed from all directions IPX4.

	Foreign Bodies (First digit)		Liquids (Second Digit)
0	No protection	0	No protection
1	Protected against solid objects greater than 50mm e.g. Accidental touch by hands.	1	Protection against vertically falling drops of water e.g. condensation.
2	Protected against solid objects up to 12mm e.g. Fingers	2	Protection against direct sprays of water up to 15 degrees from vertical
3	Protected against solid objects greater than 2.5mm e.g. Tools and wires	3	Protection against direct sprays of water up to 60 degrees from vertical
4	Protected against solid objects greater than 1mm e.g. Small Tools and wires	4	Protection against water sprayed from all directions - Limited ingress permitted.
5	Protected against dust, limited ingress e.g. no harmful deposit.	5	Protection against low pressure jets of water from all directions - Limited ingress permitted.
6	Totally protected against dust.	6	Protection against high pressure jets of water (Used on ship deck) - Limited ingress permitted.
		7	Protected against the effects of immersion between 15cm and 1m
		8	Protected against long periods of immersion under pressure.