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Lighting

December 1, 2015

Bedroom with subtle lighting

The appropriate lighting scheme can have a hugely positive impact on the quality of a space, making it appear larger and more inviting. Good lighting schemes are atmospheric and free of flicker and flare. The most appealing lighting schemes have a contrast ratio of 100:1, which interestingly is the most difficult for the eye to adjust to. There are 3 main categories of lighting;

  • Ambient – this is general lighting used to boost or replace natural levels of daylight
  • Task – this is used for specific jobs or areas, e.g. for reading, chopping vegetables etc
  • Accent – this is used to highlight certain features or areas of a room over others

Tip: In general brightly lit spaces will appear bigger than dimly lit spaces but overly-bright spaces can appear characterless and harsh.

Entrances: You need a good general light to make a hallway warm and welcoming. Also the hall is generally where the post is opened so the light levels need to be bright enough to read in. Hallway lights can often be left on for long periods, so energy-saving bulbs can be a good option in these areas.

Staircases: For safety reasons, staircases should be well-lit and directed in such as way as to define the edges of the steps. The simplest way to do this is to hang a bright pendant lamp at the top of the stairs which creates a shadow along the edge of the stair risers. This is another regularly used area that could benefit from energy-saving bulbs.

Landings: Flush fittings or recessed downlights can help to maximise the available space in these typically small heavily trafficked areas. Fitting a dimmer switch on a landing allows you to maintain a low-level of light all night for guests or children.

Living rooms: The living room is generally the focal point of the whole house and where we carry out different activities that require different types of lighting. In general, you will need a combination of lighting to suit all the different functions. Overhead or wall lighting will provide ambient lighting that suits most tasks while portable table, floor or task lamps are ideal for close-up work such as reading or studying. Accent lighting behind cornices, bookshelves or glassware displays can be very useful in setting a relaxing tone and picture lights or spotlights work well to create drama in a living room.

Dining rooms: Dining rooms often serve multiple functions and so lighting in this space will need to be flexible. Whatever the lighting scheme it is important that it focuses on the dining table as the main feature.

Kitchens: Kitchen lighting needs to be planned in relation to the positions of work surfaces and appliances. Typically a good level of general light is provided by fluorescent lights, downlighters or directional spotlights. Portable lighting in kitchens is not advisable because the trailing flexes can be potentially hazardous.

Bathrooms: Bathroom lighting needs to be functional and planned with safety in mind. All lights in a bathroom can either be switched by a pull cord within the bathroom or a light switch situated outside the bathroom. Light fittings in bathrooms must have an IP rating appropriate to the zone in which they are fitted into. An IP (Ingress Protection) rating relates to a light fitting’s resistance to ingression or penetration by either a foreign body (e.g. tools, fingers, dust etc) and/or liquids or vapour. With respect to lighting there are 4 zones in a bathroom. Zone O is inside the bath or shower itself. Any fitting used in this zone must be low voltage, (max 12v) and be rated at least IP67 which is total immersion proof. Zone 1 is the area above the bath to a height of 2.25m from the floor. In this zone a minimum rating of IP44 is required. If the fitting is 240v a 30ma residual current device (RCD) must also be used to protect the circuit in this zone. Zone 2 is an area stretching 0.6m outside the perimeter of the bath and to a height of 2.25m from the floor. In this zone an IP rating of at least IP44 is required. It is also good practice to consider the area within a 60cm radius of a tap as zone 2. Zone 3 is anywhere outside zones 0, 1 and 2 (subject to specific limits) and where no water jet is likely to be used. In this zone an IP rating of IP20+ is required. If there is a likelihood of water jets being used for cleaning purpose in zones 1,2 and 3 a fitting rated with a minimum of IP65 must be used.

Tip: It is wise to avoid lighting fittings containing wood, leather or fabric in kitchens and bathrooms as they may degrade in the humid atmosphere.

Tip: Overly-bright lighting in bathrooms can cause glare as it reflects off the polished surfaces of sanitaryware and tiles.

Bedrooms: Many bedrooms contain televisions and computers and lighting should be planned around these appliances. If you read in bed, you will obviously need table lamps or directional spotlights. For applying make-up you will need a table lamp or illuminated mirror. You may need a task lamp for studying. The bedroom is also an ideal place to install dimmer switches to adjust the light levels for various moods and times of the day and spotlights directed towards wardrobes can help when selecting clothes.

Children’s rooms Lighting for children’s rooms should be safe, bright and colourful. Bright, general lighting will be needed for children playing on the floor plus while a task lamp is useful for studying. Low hanging pendant lights, clip spotlights or table lamps are unsuitable for younger children’s rooms because the cords can be a hazard. You may find a dimmer switch beneficial if your child is afraid of the dark, however some feel it is better to have a dark bedroom and a well lit landing.

Commercial Buildings
Commerical buildings must have emergency lighting in the event of a fire or power shortage and this emergency lighting has to be certified by those who supply the equipment. Although you are only required to provide a lighting level of 10lux on escape routes in commercial buildings the light emitted from ‘Exit’ signs is not taken into account.

Tip: Bright light is important in spaces where people need to be able to read facial expressions such as in a video conferencing room or lecture theatre.

Below is a table listing the lux level of certain areas

Comparative Light Levels lux
Bright Sunlight
Worktop near window
Precision task lighting
Drawing boards
Kitchen preparation areas
General Reading
Entrance Halls
Corridors, Storage
Full moon on clear night
100,000
3,000
1,000
750
500
300
150
100
1

Tip: Plants won’t live long in light levels lower than 500 lux. Metal halide lamps are said to be the best lamps for plant growth.

Types of Light Fittings
Pendants / Suspended are fitted to the ceiling of a room and are normally found at the centre. They are a versatile way of lighting large areas and come in a vast array of styles.

Wall Lights can be used on their own, or in addition to a pendant in larger rooms. Depending on the lux level they output and their location they can provide either ambient and / or accent lighting. They are also useful in spaces with low ceilings.

Tip: Diffuse / ambient lighting is good at hiding imperfections in surfaces while focussed lighting is good at picking out texture.

Track lighting is a sleek, modern way of lighting a room. They are an effective way of directing light to where it is needed most and are available with different numbers of bulbs depending on the size of your room.

Table/Floor Lamps are a flexible way of lighting rooms and are fantastic for creating accent lighting.

Tip: When positioning lights aim to have light outside a person’s 45 degree viewing angle

Recessed lighting has become very popular in modern homes in Ireland. Most people fit too many downlights in their rooms so aim for a spacing of more than 1200mm  between fittings. Also be sure that the fittings are easy to access for bulb changing.

Bulb types
Incandescent bulbs are the conventional bulbs that we all recognize, the most popular being the ubiquitous Tungsten bulb. They work by heating an electric element encased in thin, transparent or pearlised glass to white-hot temperatures, throwing off a warm yellowish light that flatters skin tones and imparts a warm feeling to a room. In comparison to fluorescent lamps they have a relatively short life (around 1000 hours) and are very inefficient energy-wise. Incandescent lamps come in a variety of shapes and sizes and have a number of different cap styles and coatings. A pearl coating is an all over frosting which diffuses the light from the bulb while clear bulbs are ideal where sparkle is required such as in a crystal chandeliers.

A Halogen bulb is a variation on the standard incandescent bulb. It combines halogen gas with tungsten inside a quartz shell to yield a hotter, brighter light. Halogen bulbs produce a very attractive light that closely resembles sunlight and is why it is the bulb most commonly used to illuminate artwork and retail goods. They are more efficient than incandescent bulbs using only half the energy to produce the same light output while lasting twice as long. Halogen bulbs can generate a lot of heat so they can only be used in light fittings designed to cope with the higher temperatures. They can be dimmed but only with special dimmers. There are two main types of halogen lamp available in the domestic market low voltage and mains voltage. Low voltage halogen bulbs operate on 12V so a transformer has to be fitted either in the light fitting itself or near to it. The lower voltage of this type of bulb enables manufacturers to produce interesting and slim designs than is possible with higher voltage bulbs. Transformers can be either electronic or ‘wire wound’. The newer electronic transformers are more energy-efficient and smaller than the conventional wire wound type but they can be more expensive. Electronic transformers can be damaged by voltage ‘spikes’ in the mains supply. These spikes can be caused by fluorescent lights, older motors, fridges, lift shaft motors etc. If persistent problems occur the use of mains voltage lighting is recommended. Mains voltage halogen bulbs are a relatively new breed of lamps offers the light colour advantages of halogen without the need to house a transformer. G10, G9 are both types of halogen lamps. IRC halogen lights use 30% less electricity than standard halogen lights and have a lifespan of 5000 hours.

Tip: Although more energy-efficient than traditional incandescent bulb, halogen bulbs get very hot when in use so avoid using them in areas accessible to children.

Xenon
A newer form of incandescent, Xenon globes are filled with xenon gas and have a carbon filament, which results in a brighter, longer-life light source. Unlike halogen, xenon globes produce less heat, hence they require no lens or glass cover for protection. Xenon globes are low voltage, can be dimmed and are typically used as cove or cabinet strip lighting.

Fluorescent bulbs
Fluorescent bulbs are also currently the most economical, energy-efficient residential lighting available on the market. Fluorescents produce less heat than incandescents, but currently can’t be dimmed without costly special components. They are ideal for lighting hard-to-reach areas or areas that need to be lit for extended hours. Fluorescent bulbs are not suitable for rooms that have their lights switched on and off frequently as it takes 1 hours worth of illumination is used to start a fluorescent light. Fluorescent bulbs typically provide very even, flat illumination and although ‘warm white’ bulbs are available they generally yield a harsh, greenish-blue light, making them a less appealing option for living areas.  Fluorescent bulbs use only 20% of the energy consumed by conventional light bulb for the same lux output and last up to 8000 hours. Triphosphor fluorescent tubes give 12% more light than standard fluorescent bulbs for same wattage and are good for displaying merchandise. Electronic Control Gear for Fluorescent Tubes reduce electricity by 22%, increases tube lifespan to 20,000hrs, gives flicker free start up.

Energy saving: Energy-saving light bulbs come in four types.

  • Compact fluorescent lamps (CFLs) – the most common type, use 60-80% less energy than an incandescent bulb, and generally the cheapest option.
  • Halogens – use 20-30% less energy than an incandescent, although they have a similar tungsten filament.
  • LEDs – use 90% less energy than an incandescent but much more expensive than a CFL
  • Fibre Optics

Tip: Metal halide and mercury vapour lamps become very inefficient towards the end of their life while fluorescent and incandescent lamps run at almost 100% prior to failure.

Compact Fluorescent or CFL bulbs are very long-lasting and are currently the most energy-efficient of all bulb types. The light level they produce is somewhere between that of tungsten and a halogen bulbs. They generate very little heat for light fittings within the reach of children. On the downside they take a few moments to achieve full illumination when turned on and so aren’t ideal for areas that are only used for a few minutes at a time, i.e. store rooms, etc. Softone CFL bulbs use 80% less electricity and last 6 times longer than traditional tungsten bulbs. Professional long-life CFL uses 80% less electricity, last 15 times longer than tungsten bulbs.

A 23 watt CFL / 105 watt Halogen bulb is the equivalent of a 150 incandescent bulb.
A 20 watt CFL / 70 watt Halogen bulb is the equivalent of a 100 incandescent bulb.
A 15 watt CFL / 53 watt Halogen bulb is the equivalent of a 75 incandescent bulb.
An 11 watt CFL / 42 watt Halogen bulb is the equivalent of a 60 incandescent bulb.
A 9 watt CFL / 28 watt Halogen bulb is the equivalent of a 40 incandescent bulb.

Contemporary and cost-effective, tiny LEDs can be incorporated into all sorts of residential lighting designs – as sconces, step or marker lights, strip or under-cabinet lighting. As they don’t produce much heat when on they are ideal for areas accessible to children. Currently the light levels produced by LED bulbs is not as high as that achieved with other bulb types and so you may need more fittings per square metre than you would with other bulb types.

Fibre-optic lights combine bundles of glass or plastic fibres with a remotely located halogen or metal halide bulb.  Low-voltage fibre-optics are suitable for feature installations and displays. Side-emitting systems are great for defining outlines while end-emitting systems gives a ‘twinkle’ effects. Cheaper fibre optic cables are made from plastic, diminishing the quality of the light and potentially causing a shift in the colour of light as it travels down a fibre optic cable.

Tip: When choosing a bulb type consider colour rendering qualities, size, energy efficiency, light level emitted, maintenance and cost of replacement.

Below is a table outlining the colour rendering index of different bulb types. This is particular important in retail or museums where accurate colour rendering is critical.

CIE Colour Rendering Index
RA Group
100
90
80
60
40
Where accurate colour matching is required, e.g. printing
Where good colour rendering is required, e.g. shops
Where moderate colour rendering is acceptable
Where colour rendering is of little significance
Where colour rendering is of no importance
1A
1B
2
3
4

Light colour is measured in degrees Kelvin. Below is a table that gives the Kelvin rating for particular bulb types.

Colour Temperatures K
Blue Sky
Uniform Overcast Sky
Average Natural Daylight
HP Mercury cool white lamp
Fluorescent warm white lamp
Halogen filament lamp
GLS tungsten filament
HP sodium lamp
10,000
7,000
6,500
4,000
3,000
3,000
2,700
2,050

Bulbs come with a variety of cap types. There are four main cap types include bayonet cap (BC), small bayonet cap (SBC), Edison screw (ES) and small Edison screw (SES)

Light Switch Types
Your standard light switch is called a rocker switch and it can have 1, 2, 3 or 4 switches on it. The term ‘gang’ refers to the number of switches while the term ‘way’ refers to the number of switches chosen to activate the light. Lights can either be switched on and off by one switch (single way), two switches (two-way) or three switches (three-way).

Dimmer switches provide a relatively inexpensive and uncomplicated way to vary the intensity of light in a room. The dimming of bulbs can also save energy, as dimming a bulb’s light output will normally reduce its energy consumption. Most tungsten and halogen bulbs are dimmable but only certain types of fluorescent bulbs can be dimmed. Sodium / Halide bulbs can’t be dimmed. When installing a dimmer switch you need to check that the light fitting is compatible with the dimming device and that the dimmer has sufficient capacity to control the load on the circuit. Dimming systems can have forward or reverse phased dimming systems and transformers need to match the direction of the control systems. There are several methods of dimming a fitting:

Touch Dimmer: This is a safe, modern way of dimming lights and works by “induction”. Touching the light either dims the light to off or dims the light in stages (eg full, medium, low and off). T

Switch Dimmer: This is either controlled by a slider or a rotating knob.

Remote Dimmer: This is generally a touch sensitive switch that can also be worked by remote control. The remote control will normally control more than one remote dimmer switch and can be ‘trained’ to remember the lighting level on each one.

Why does my dimmer buzz?
Some wall mounted switches may emit an annoying hum when turned to their lowest setting. This is quite normal but will vary in intensity depending the type of dimmer switch and the type of light fitting being dimmed. Reducing the bulb wattage may resolve the issue, if not a different dimmer switch may alleviate the problem.

Glossary

A bulb fits into a lamp which fits into a luminaire which sits into a lighting scheme

A luminaire is a structure that holds a lamp or bulb.

A light fitting is defined as a permanently fixed luminaire.

Watts used to be the way to tell bulbs apart when the only choice was between incandescent bulbs but watts are a measurement of how much power a light bulb draws, rather than of how bright a bulb is.

Lumens are the unit used to measure light output, or brightness and  lux levesl refer to the number of lumens per sqm. Footcandles is defined as the number of lumens per sqft.

The table below shows lumen ratings on the left, the equivalent wattage of incandescent bulb next, and then the equivalent wattages for CFL, halogen and LED energy-saving bulbs.

Wattage and maximum lumen output comparison
Maximum light output measured in our tests Incandescent bulb wattage CFL wattage Halogen energy saver wattage LED wattage
200-300lm 40W 7, 8 and 9W n/a 5 & 6W
300-400lm 40W 7, 8 and 9W 28W n/a
400-500lm 40W 8, 9 and 11W n/a n/a
500-600lm 60W 8 & 11W 42W n/a
600-700lm 60W 11W 42W n/a
700-800lm n/a 11 & 15W 52 & 53W n/a
800-900lm n/a 15W 53W n/a
900-1000lm 100W 15W n/a n/a
1000-1100lm 100W 15 & 20W n/a n/a
1100-1200lm 100W 20W n/a n/a
1200-1300lm 100W 20W n/a n/a

Thanks to the following website where i sourced some of this information from http://www.which.co.uk, http://www.freemans.com, http://www.falkslighting.ie

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