1. Area classification is a method of analyzing and classifying the areas where explosive gas at- mospheres may occur. The object of the classification is to allow the selection and design of electrical apparatus able to be operated safely in these areas.

2. Hazardous areas for FC system are divided into zones 0, 1 and 2 and the classification is to be in accordance with 303.

3. Areas and spaces other than those classified in 303 are to be subject to special consideration.

The principles of the IEC 60079-10 standards are to be applied.

4. Area classification of a space may be dependent of ventilation as specified in IEC 60092-502.

Requirements for such pressurization are given in 110.

5. A space with opening to an adjacent hazardous area on open deck, may be made into a less hazardous or non-hazardous space, by means of overpressure. Requirements for such pressuriza- tion are given in 110.

6. Ventilation ducts are to have the same area classification as the ventilated space.

303.

Hazardous area

1. Zone 0

(1) The Zone 0 includes following.

(A) The interiors of gas tanks

(B) The interiors of pipes and equipment containing gas

(C) Any pipe work of pressure-relief or other venting systems for gas tanks

(2) Instrumentation and electrical apparatus in contact with the gas or liquid are to be of a type suitable for zone 0.

(3) Temperature sensors installed in thermo wells, and pressure sensors without additional separating chamber are to be of intrinsically safe type Ex-ia.

(4) Cables are to have armouring or shielding, or to be laid in a metallic tube.

2. Zone 1

(1) The Zone 1 includes following.

(A) Tank room

(B) Gas compressor room arranged with ventilation in accordance with 110. 5.

(C) Areas on open deck, or semi- enclosed spaces on open deck, within 3m of any gas tank outlet, gas or vapour outlet (such areas are, for example, all areas within 3m of gas tank hatches, ullage openings or sounding pipes for gas tanks located on open deck and gas va- pour outlets), bunker manifold valve, other gas valve, gas pipe flange, gas pump-room ven- tilation outlets and gas tank openings for pressure release provided to permit the flow of small volumes of gas or vapour mixtures caused by thermal variation.

(D) Areas on open deck or semi-enclosed spaces on open deck, within 1.5 m of gas compressor and pump room entrances, gas pump and compressor room ventilation inlets and other open- ings into zone 1 spaces.

(E)

(F)

Areas on the open deck within spillage coamings surrounding FC fuel bunker manifold valves and 3m beyond these, up to a height of 2.4 m above the deck.

Enclosed or semi-enclosed spaces in which sources of release are located, e.g. ducts around

FC fuel pipes, semi-enclosed bunkering stations. However, open ended ventilation pipes from FC fuel piping systems will not create a hazardous zone in a surrounding well ventilated space.

(2) Cables are to have armouring or shielding, or to be laid in a metallic tube.

3. Zone 2

(1) The Zone 2 includes following.

(A) Areas within 1.5 m surrounding open or semi-enclosed spaces of zone 1 as specified in

para 2, if not otherwise specified in this Guidance.