AS NZS 1680.4:2017 pdf free.Interior and workplace lighting Part 4: Maintenance of electric lighting systems.
2.1 GENERAL
All lighting schemes within a building will deteriorate progressively from the time they are installed. The losses are due to the accumulation of dust and dirt on all exposed surfaces of lamps, luminaires and room surfaces—reducing the transparency or reflecting power—and to the decay in lamp lumen-output, failing lamps and ageing of surfaces. If this process is unchecked, it will result in the illuminance falling to very low values as shown in Figure 2.1, and the lighting system may become ineffective and possibly dangerous. As the decay is gradual, the occupants may not notice the loss of illuminance until they become aware of visual difficulty or other possible consequences such as increased errors, tasks taking longer to perform, and accidents.
Regular maintenance is therefore most important for an effective lighting system. Not only should the lighting system be cleaned correctly and thoroughly but also the cleaning should be carried out at regular intervals. A well-designed maintenance program will maintain the required illuminance, reduce capital and operating costs and run the system safely. It will ensure satisfactory appearance and comfort for the occupants.
However, even with a well-designed and well-operated maintenance program, some loss of illuminance is inevitable. This loss has to be estimated at the time the lighting scheme is planned, and an allowance in the form of a maintenance factor should be included in the scheme design calculations.
2.2 INFLUENCING FACTORS
There are several factors that can reduce the light output. These are grouped under non- recoverable and recoverable depreciations.
Non-recoverable factors, such as the progressive deterioration of light transmitting or reflecting surfaces of lurninaires, are inherent to the lighting system and its environment and cannot be improved during normal maintenance or are uneconomical to overcome. At the specification stage of a lighting system, these factors should be taken into account together with the planning of a maintenance program.
If the influence of other factors, such as voltage, frequency, temperature and ballast, is permanent and significant then, at the design stage, the magnitude of these effects should be estimated and an allowance similar to the maintenance factor should be made in the calculations. The influence of random occurrences may be ignored, provided they do not harm the operation of the lighting system.
Recoverable factors such as lamp lumen maintenance, lamp survival, luminaire maintenance and room surface maintenance can be made good during routine maintenance by relamping, cleaning, replacement of components or painting surfaces.AS NZS 1680.4 pdf download.