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9.8 Designing Artificial Illumination Systems

Design involves:

- choice of the system of illumination;
- type of lighting source;

- lamp type;

- choice of location of lighting devices;

- calculations;

- definition of lamp and bulb power.

A system of general or combined illumination is designed for all industrial
buildings. The lighting of the working area by lamps of general lighting in the system
of combined lighting has to be no less than 10 % of combined lightning standard but
not lower than 150 lx for gas-discharge lamps and 50 lx for incandescent lamps.
From the economic point of view, luminous tube lamps of LB type are the best
as they have the highest light efficiency. The minimal height from the floor at which
the lamps are to be installed is 2.6 m for a 4-bulb lamp and 3.2 for lamps with 4 and
more bulbs.
The selection of a lamp depends on workplace characteristics. For buildings
whose walls and ceiling have a low reflecting capacity, lamps of direct effect are
used. For buildings whose walls and ceiling have a high reflecting capacity, lamps
mainly of direct effect are used.
In administrative and office buildings, lamps of diffused illumination are
common. Lamps must have a proper protection level from conditions of the
environment where they are fixed.

Operation of Lighting Devices:
Windows have to be cleaned at least two times a year if the dust level is rather
low and at least four times if the emission of dust is high. The frequency of lamp
cleaning is 4–12 times a year (depending on dust level).
The level of illumination of controlled places must be checked regularly at
least once a year.

Revision Questions

1) Why is good lighting at work important?
2) Who is responsible for lighting at work and what are their legal
responsibilities?
3) Lighting hazards.
4) Factors that determine visual comfort.
5) Basic light engineering Notions.

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