Zonal & Luminaire Classifications

ZONAL CLASSIFICATION

British Standard 13S5345: Part 1 defines areas of risk as:

Zone 0 - where an explosive gas-air mixture is continuously present or present for long periods.

Zone 1 - where an explosive gas-air mixture is likely to occur in normal operation.

Zone 2 - where an explosive gas-air mixture is not likely to occur in normal operation and if it appears it is only present for a short period.

Prior to the introduction of BS5345, Zones were called DIVISIONS as defined in BSCP1003: 1964.

The above Zonal Classifications deal only with risks due to to flammable gases and vapours and, by implication, flammable mists.

Dust hazards are not included as they will be treated in a separate document currently under preparation.

By implication, an area that is not classified Zone 0, 1 or 2 is deemed to be non-Hazardous and so standard industrial electrical equipment can be used.

The classification of an area into appropriate zones is normally carried out by a multi-discipline team involving process and engineering personnel with detailed knowledge of the likely risks. For smaller plants the local factory inspector or fire officer may undertake the task. It must be stressed that a luminaire manufacturer is not authorised to classify zones in premises.

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CLASSIFICATION OF LUMINAIRES

Extract taken from CIBSE lighting code

Table 2. Classification of luminaires according to the material of the supporting surface for which the luminaire is designed (from BS 4533).
DESCRIPTION OF CLASS	SYMBOL USED TO MARK LUMINAIRES
Luminaires suitable for direct mounting only on non-combustible surfaces	No symbol - but a warning notice is required
Luminaires without built-in ballast or transformers, suitable for direct mounting on normally ßammable surfaces	No symbol
Luminaires with built-in ballast or transformer suitable for direct mounting

Table 3. Information which should be marked on luminaires (from BS 4533).
1.	Mark of origin.
2.	Rated voltages(s) in volts. (Luminaires for tungsten filament lamps are only marked if the rated voltage is different from 250 volts).
3.	Rated maximum ambient temperature if other than 25°c (ta...°C).
4.	Symbol of class II or class III luminaire, where applicable (see table 2 above).
5.	Ingress protection (IP) number, where applicable (see table 1).
6.	Maker's model number or type reference.
7.	Rated wattage of the lamp(s) in watts. (Where the lamp wattage alone is insufficient, the number of lamps and the type shall also be given. Luminaire for tungsten filament lamps should be marked with the maximum rated wattage and number of lamps.)
8.	Symbol for luminaires with built-in ballast or transformers suitable for direct mounting on normally flammable, surfaces, if applicable (see table 2 above).
9.	Information concerning special lamps, if applicable.
10.	Symbol for luminaires using lamps of similar shape to 'cool beam' lamps where the use of a 'coolbeam' lamp might impair safety.
11.	Terminations to be clearly marked to identify which termination should be connected to the live side of the supply, where necessary for safety or to ensure satisfactory operation. Earthing terminations should be clearly indicated.
12.	Symbols for the minimum distance from lighted objects, for spotlights and the like, where applicable.

In addition to the above markings, all details which are necessary to ensure proper installation, use and maintenance should be given either on the luminaire or on a built-in ballast or in the manufacturer's instructions provided with the luminaire.