Section 1 General

101. Application

1. The requirements which not specified in this Chapter, it is to be in accordance with Ch 7 of

Guidance for Floating Production Units. For cargo area are to be in accordance with Pt 7, Ch

5 of Rules for the Classification of Steel Ships.

2. For the purpose of this Chapter :

(1) An enclosed space is considered to be a space bounded by bulkheads and decks which may have doors, windows, of other similar openings.

(2) A semi-enclosed location is considered to be a location where natural conditions of ventilation

are notably different from those on open decks due to the presence of structure such as roofs, windbreaks and bulkheads and which are so arranged that the dispersion of gas may not occur.

102. Definition of hazardous area

1. Hazardous areas are all those areas where, due to the possible presence of a flammable atmosphere arising from the drilling operations, the use without proper consideration of machinery or electrical equipment may lead to fire hazard or explosion.

2. Hazardous areas are divided into zones as follows;

Zone 0: an area in which an explosive gas-air mixture is continuously present or present for long periods.

Zone Zone

1: an area in which an explosive gas-air mixture is likely to occur in normal operating conditions.

2: an area in which an explosive gas-air mixture is not likely to occur, and if it occurs, it will only exist for a short time.

103. Definition of Gas-dangerous space or zone

1. The Gas-dangerous space as specified may be extended or reduced depending on the actual arrange- ments in each case, by use of windshields, special ventilation arrangements, structural arrangements, etc.

2. "Gas-dangerous space or zone" is:

(1) a space in the cargo area which is not arranged or equipped in an approved manner to ensure that its atmosphere is at all times maintained in a gas-safe condition;

(2) an enclosed space outside the cargo area through which any piping containing liquid or gaseous

products passes, or within which such piping terminates, unless approved arrangements are in- stalled to prevent any escape of product vapour into the atmosphere of that space;

(3) a cargo containment system and cargo piping;

(4) (a) a hold space where cargo is carried in a cargo containment system requiring a secondary barrier;

(b) a hold space where cargo is carried in a cargo containment system not requiring a secon-

dary barrier;

(5) a space separated from a hold space described in (4) (a) by a single gastight steel boundary;

(6) a cargo pump room and cargo compressor room;

(7) a zone on the open deck, or semi-enclosed space on the open deck, within 3 m of any cargo tank outlet, gas or vapour outlet, cargo pipe flange or cargo valve or of entrances and ven- tilation openings to cargo pump rooms and cargo compressor rooms;

(8) the open deck over the cargo area and 3 m forward and aft of the cargo area on the open deck up to a height of 2.4 m above the weather deck;

(9) a zone within 2.4 m of the outer surface of a cargo containment system where such surface is

exposed to the weather;

(10) an enclosed or semi-enclosed space in which pipes containing products are located. A space which contains gas detection equipment complying with Pt 7, Ch 5, 1306. 5 of Rules for the Classification of Steel Ships and a space utilizing boil-off gas as fuel and complying with Pt 7, Ch 5, Sec 16 of Rules for the Classification of Steel Ships are not considered gas- dangerous spaces in this context;

(11) a compartment for cargo hoses; or

(12) an enclosed or semi-enclosed space having a direct opening into any gas-dangerous space or zone.