Summary of design considerations

• Design of artificial lighting systems should not be extravagant, lighting levels should be designed be to as low as is permitted whilst still achieving the standard required.

• Task lighting should be used for specific workstations in order to reduce the level of general background lighting.

• Energy efficient lamps should be specified - usually high frequency fluorescent or alternative discharge lamps; compact fluorescent lamps should be specified where appropriate.

• Appropriate luminaires, giving energy efficient light distribution, should be chosen.

• Control gear (ballasts) required for lamp functioning should be energy efficient, for example high frequency electronic ballasts are up to 20 per cent more efficient than the norm.

The on/off controlled switching of lighting systems needs careful consideration for optimum performance. Four types of control are available.

Timed control

• Used to switch lights off automatically according to a specified schedule; with lights switched on manually.

• Lights near windows should be separately controlled; this can produce savings in spaces regularly used by more than two people.

Occupancy linked control

• Sensors (ultrasonic, infra-red, microwave or acoustic) are used to detect presence of occupants.

• Switching on is for a set period, lights switched off if presence no longer detected.

• This type is particularly appropriate for spaces with low occupancy levels.

Daylight linked control

• Can be used in conjunction with timed and occupancy linked systems.

• Photocells are installed to detect when natural light is sufficient at which point artificial lighting is switched off.

• Recent developments include use of dimming control to avoid abrupt change as lights are switched off.

Localised switching

• Allows partial illumination of large areas when not fully occupied.

• Gives individual control to occupants.

• Some form of override switching off required when building becomes unoccupied.

To conclude, of all the factors under the designer's control, lighting is probably the most powerful influence on mood and demeanour. It makes direct contact with the emotions. As such its disposition, quality and means of control are critical factors in determining the well-being of the occupants of a building. Leaving aside the moral arguments, this can have a direct effect on the bottom line.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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