PRINCIPLES OF LIGHTING DESIGN (3RD YEAR) A.O.

Principles of Lighting Design

 

Light is an essential element of every interior scheme and should be given special attention in the initial plan of each room.  Sufficient and conveniently planned outlets should be an integral part of architectural planning.  Planning of artificial light presents a major problem, as it requires both aesthetic and practical considerations.  The average room lighting equipments and fixtures must be consistent with the style of the décor and must consistently contribute to the character and atmosphere of the room.

TYPES OF LIGHTING

Ø  Natural

Day light provides natural light and varies according to the position of the sun and time of the day.  Light is necessary for colour visibility. Textures are also influenced by light absorbed or reflected by them.

Ø  Artificial

These are of two types:

Incandescent Lighting:

In this type of lighting tungsten filament is sealed in a glass bulb and heated to a point at which it glows.  The glass bulbs are usually made of standard lined glass/heat resistant borosilicate glass, which permits higher voltage used for outdoor lighting.  Same bulbs are finished with an acid solution from inside which etches the glass and gives a frosted effect.

Fluorescent Lighting:

This consists of sealed glass tubes, which contains mercury and halogen glass. It has electrodes at each end and on the inside, the tube is coated with a florescent material containing phosphorous. When a current is passed, the mercury vapour emits ultra violet light which is converted into visible light by the phosphorous on the inside surface of the tube.

The lifespan of the incandescent lamp would be 750-2000 hrs and of a fluorescent light 1800-20000 hrs. Fluorescent lamps are suited for lower ceiling application and general lighting.  They provide diffused light.

CONSIDERATION IN LIGHTING SELECTION

1.    Function:

The function of lighting must be evaluated in terms of quantity and quality of vision. The primary goal is visual clarity and to safeguard guest.

2.    Safety:

Safety is important in light consideration since improper lighting could prove hazardous to persons working in a particular area.  Staircases require adequate lightings to prevent accidents. Proper wiring insulations and earthing should also be considered for safety.

3.    Beauty:

A close relationship exists between the type of lighting and appearance of colour.  Wrong colour choices reduce the effectiveness of well-planned schemes.  The designer should use brightness/ contrast to create visual interest. Interior lighting should be an integral part of the total designing of the area.

METHODS OF LIGHTING

1     ARCHITECTURAL LIGHTING: It supplies functional lighting and is good for contemporary rooms.

a.    Valence Lighting:

A historical fluorescent tube is placed behind a valence board, carting up light which reflects and then down, shining on the drapery by providing both direct and indirect light.

b.     Cornice Lighting:

A cornice is insulated in ceiling and directs the light downward.  It can provide a dramatic effect on drapery, wall covering and pictures.

c.    Covered Lighting:

Covered lighting consists of placing a series of continuous fluorescent tubes in a group or placed at one or more walls of a room.

d.    Soffit Lighting:

This is a method of direct lighting in which the illumination from the light source is built into the underside of soffits or beams used in staircases, reception, lounges etc.

e.    Luminous Lighting:

This is recessed lighting to light up a particular area e.g. kitchens, utility areas, bathrooms etc.

2     NON ARCHITECTURAL LIGHTING

This consists of the light reflected from walls and ceilings. Portable lamps may also be used for general overall light or localised light.

3     OTHER LIGHTING

Table lightings, point source, accent diffused and ambient lighting.

LIGHTING SYSTEMS:

Types of lightings may be classified by the manner in which the light rays are directed on the object to be illuminated.

1     Direct Lighting:

It is a type of light that is produced by most table and floor lamps.  The light is directed downwards and the ceiling receives reflected light. This light produces sharp shadows and some times a glare.  Direct lighting is usually combined with other types of lighting according to the requirements e.g. spot lightings.

2     Indirect Lighting:

In this type of lighting, the light is directed to the ceiling or walls from which it is reflected into the rooms.  The immediate light source is secluded from view. Overall, room illumination with indirect lighting will diffuse or shadow less with low, less, light source brightness.  When used above, indirect lighting is flat and uninteresting without shadows. It is suitable for general lighting of the covered valence and cornice fitting.  Other lighting systems are semi direct and semi indirect lighting.

LIGHT FITTINGS

1.    Dimmers:

These are combined with on and off switches and control the level of lights on & off at one certain time or at different times in different rooms.  Several dimmers can be attached to a single control.

2.    Anti Burglar:

These lights function on a time switch which turn the lights on and off at a certain time or at different times in different rooms.

3.    Door Switch:

This light is set in the doorframe and gets turned on when the door is opened.

4.    Photo Cell Control:

Light sensitive units can replace switches at the entrance where a photocell card needs to be installed to activate the lights.

5.    Full Fittings or Pendant Lights:

These are fitted over dining tables, billiards table and for spot lighting.  The control switch may be a finger tap switch provided at the table.

LIGHTING FOR DIFFERENT AREAS IN HOTELS

1.    Entrance Halls:

Entrance halls should look interesting and the lighting should be in keeping with the atmosphere of the place. During the day, an entrance can appear dull and dim if one comes from outside. The light in the hall should be bright enough at the reception desk, on display boards etc.  Care should be taken to avoid glare but the light should be sufficient for the guest to be able to read clearly.

2.    Lounge Area:

In the lounge area, a chandelier or a general light fitting may be fixed to provide overall light. Cornice lighting may be fixed to reflect on the ceiling, coved lighting may be provided by using wall brackets and other fittings.  When there is a false ceiling, the light may come in through the gaps in the ceiling or through glass panels fitted in the ceiling.  Lamp fittings here are concealed and only the light is reflected. The atmosphere of the lounge should be comfortable and restful.  Localised lights may be used if necessary and portable fittings may be provided.  In case of an area attached to a cafeteria, higher degree of illumination may be necessary for quick service.

3.    Restaurants:

In restaurants, subdued lighting is generally perfected specially at heights. General lighting is normally used for banquets. Fluorescent lightings may also be used.  The effect of lighting on the colour of food should be considered. 

4.    Corridors:

Subdued lighting may be required in corridors but gloom should be avoided and the guest should be able to see the room number clearly.  Placement of light should not be very far from each other.  Cornice or ceiling lights are quite appropriate.

5.    Stairs:

Stairs should be well lit to prevent accidents.  The lights can be set along the wall or just below the handrail.  In case of overhead light, fittings should be placed at the end of each flight of stairs.

6.    Bedroom:

Bedrooms do not generally require general lighting but adequate lighting should be provided in different parts of the room.  The light should not be too bright.  A general wall light, a table lamp, bedside lights are the standard light.  Lights should be controlled at the door as well as the headboard of the bed to prevent accidents or to have the guest enter into a darkened room.  Bedside lights may be mounted on to the wall or fixed as table lamps.  They should be placed sufficiently high to enable the guest to read a book.  Dressing table light should provide sufficient light to illuminate the face and not the mirror. Pelmet lights can be fixed which illuminates the curtain and giving a soft glow around the window area.  The wardrobe built in cupboards should have one light inside to enable guests to see the contents clearly.  This light may be fixed to the ceiling of the wardrobe.

7.    Bathroom:

In a bathroom, safety is of prime importance.  The fittings must be safe with vapour and water proof fittings. All electrical fittings and equipment should have dual switches which can be controlled from outside.  Plastic or glass is preferred to metal.  An emergency light that operates independently of the main supply should be provided which comes on during power failure.  This light should be placed in staircases corridors and exit entrances.

IMPACT OF LIGHTING ON MOOD AND ATMOSPHERE

The selection of lighting systems, light intensity, its colour and the accessories used influence the mood and atmosphere of the room.  Lighting in the bedroom should be warm and relaxing. Yet, it should be bright enough to observe the articles in the room.  Light of low wattage and medium wattage is suitable.  Using dimmer switches can change the atmosphere and mood.  A series of down lighters and wall washers will be suitable to light up the room and prevent glare to the occupants.  Subsidiary lighting by the telephone, mirror, coats rack may be necessary.  In a restaurant, a relaxing mood can be created by using pelmet lights and pendent lamps above the table.  The light should be dim around the people, but with medium wattage over the food.

Passageways should be visible. Candlelights may also be used to create a romantic ambience. Bright pools of light alternating with shadows provide a warm welcome. Lights in office area must provide general light as well as spot lighting on the table.  Reading lights should be situated behind the user at the top left hand side.