Section 6 Machinery and Electrical Installations in Hazardous Areas

601. Classification of Areas of Hazardous Areas

The following hazardous areas are those which normally apply to offshore support vessels engaged in oil recovery operations.

1. Hazardous Areas Zone 0 include :

(1) The internal space of recovered oil tanks and pipes including the venting arrangements of the recovered oil tanks.

(2) Cofferdams and voids adjacent to recovered oil tanks, containing recovered oil pipe flanges, valves, or other sources of release.

2. Hazardous Areas Zone 1 include :

(1) Recovered oil pump rooms, spaces in which oil contaminated equipment for handling the recov-

54 Guidance for Offshore Support Vessels 2015

ered oil is located, and oil handling areas.

(2) Enclosed or semi-enclosed spaces in which recovered oil pipe flanges, valves, or other sources of release are located.

(3) Areas on the open deck within a 3 meter radius of any recovered oil tank opening, recovered oil tank vent, recovered oil pipe flange or valve.

(4) Areas on the open deck within a 3 meter radius of any entrance or ventilation opening to any

hazardous area zone 1 space.

(5) Areas

on the open deck within a 3 meter radius of any oil recovery equipment. Equipment in-

cludes but is not limited to skimmers, containment booms and reels, and separators.

(6) Areas

on open deck within spillage coaming surrounding oil recovery manifold valves and 3 m

beyond the coaming up to a height of 2.4 m above the deck.

3. Hazardous Areas Zone 2 include :

(1) Except machinery spaces that are isolated from recovered oil tanks by means of a cofferdam, enclosed spaces immediately adjacent to recovered oil tanks in any direction, not containing re- covered oil pipe flanges, valves, or other sources of release.

(2) Enclosed or semi-enclosed spaces having a direct access or opening to any hazardous area.

(3) Air lock spaces between Zone 1 and non-hazardous space

(4) Areas on the open deck within 1.5 m radius of any entrance or ventilation opening to any haz- ardous area zone 2 space excluding tanks adjacent to recovered oil tanks not containing recov-

ered oil pipe flanges, valves, or other sources of release.

602. Machinery Installations in Hazardous Areas

1. Mechanical equipment is to be limited to that necessary for operational purposes.

2. Mechanical equipment and machinery in hazardous areas are to be so constructed and installed as to reduce the risk of ignition from sparking due to the formation of static electricity or friction be- tween moving parts and from high temperatures of exposed parts due to exhausts or other emissions.

3. Internal combustion engines are not to be installed in the hazardous areas. The installation of in- ternal combustion machinery may be permitted in Zone 1 and Zone 2 hazardous areas, provided that the Society is satisfied that sufficient precautions have been taken against the risk of dangerous ignition.

4. Fired boilers are not to be installed in hazardous areas.

5. Exhaust outlets of internal combustion engines are to be fitted with suitable spark arresting devices.

6. Air intakes are to be located not less than 3 m from the hazardous areas.

7. Exhaust outlets haust outlets of

8. Oil recovery and so as not

and outlets of vent pipes from crankcases of internal combustion engines ande ex- boilers are to be located outside the hazardous areas.

apparatus is to be constructed so as to ensure the safety to the operator to ignite the explosive gas.

9. At least one piece of gas detection equipment is to be provided in order to detect gases in enclosed non-hazardous spaces and in other spaces deemed necessary by the Society in case those spaces contain source of ignition. One piece of portable gas detection equipment is to be provided where the fixed gas detection equipment is only provided on board.

10. Exhaust pipes or any other pipes with surface temperatures exceeding 220°C are not to pass through gas hazardous areas

11. Piping not related to the transfer of recovered oil is not to pass through recovered oil tanks un- less the piping is made of steel ,extra-heavy and of all welded construction, without valves, flanges, fittings or take-down joints.

12. Where machinery spaces are located forward of recovered oil storage tanks, propulsion shafting is not to be led through the tanks and is to be effectively grounded.

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603. Electrical equipment in hazardous areas

1. Electrical equipment in hazardous areas is to be in accordance with Pt 6, Ch 1, Sec 4 and Sec 9

of Rules for the Classification of Steel Ships.

2. Electrical cables are not to pass through recovered oil tanks unless enclosed within an oil tight trunk or equivalent.