(IV-7-3) General Safety

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Rules IV Industrial Services Part 7 Offshore Substations Chapter 3 General Safety Section 7 Passive Fire Protection vice 1 systems and vapor barriers and adhesives used in conjunction with insulation need not be noncombustible but they shall be kept to a minimum and their exposed surfaces should have low flame spread characteristics. In spaces where penetration of flammable liquids is possible, the surfaces of the insulation shall be impervious to the liquid or its vapors. A.5.9 Framing The framing, including supports and the joint pieces of bulkheads, linings, ceilings and draught stops, shall be of non-combustible material. A.5.10 Surfaces The following surfaces shall have low flame spread characteristics: • exposed surfaces in corridors and stairway enclosures • surfaces in concealed or inaccessible spaces in accommodation, service spaces and control stations • exposed surfaces of ceilings in accommodation, service spaces and control stations A.5.11 Veneers Bulkheads, linings and ceilings may have combustible veneers provided that the thickness of such veneers shall not exceed 2 mm within any space other than corridors, stairway enclosures and control stations, where the thickness should not exceed 1.5 mm. Alternatively veneers which have a caloric value not exceeding 45 MJ/m 2 of the area for the thickness used may be accepted by GL, irrespective of the thickness of those veneers. A.5.12 Deck coverings Primary deck coverings, if applied, shall be of approved materials, which will not readily ignite or give rise to toxic or explosive hazards at elevated temperatures. A.5.13 Paints and varnishes Paints, varnishes and other finishes used on exposed interior surfaces shall not offer an undue fire hazard in the judgment of GL and shall not be capable of producing excessive quantities of smoke or toxic fumes. B Ventilation and Fire Dampers B.1 Materials Ventilation ducts shall be of steel or equivalent material. Short ducts, however, not generally exceeding 2 m in length and with a cross-sectional area not exceeding 0.02 m 2 need not be non-combustible, subject to the following conditions: • these ducts shall be made of heat resisting non-combustible material, which by be faced internally and externally with membrances having low flame-spread characteristics and, in each case, a calorific value not exceeding 45 MJ/m 2 of their surface area for the thickness used • they may only be used at the end of the ventilation device • they shall not be situated less than 600 mm, measured along the duct, from where it penetrates any "A" or "B" class division including continuous "B" class ceilings –––––––––––––– 1 Cold service is understood to mean refridgration systems and chilled water piping for air-conditioning systems (MSC/Circ.1120) Edition 2013 Germanischer Lloyd Page 7–6
Rules IV Industrial Services Part 7 Offshore Substations Chapter 3 General Safety Section 7 B.2 Ducts Passive Fire Protection B.2.1 Where ventilation ducts with a cross-sectional area exceeding 0.02 m 2 pass through class "A" bulkheads or decks, the opening shall be lined with a steel sheet sleeve unless the ducts passing through the bulkheads or decks are of steel in the vicinity of penetrations through the deck or bulkhead, the ducts and sleeves at such places shall comply with the following: B.2.2 The ducts or sleeves shall have a thickness of at least 3 mm and a length of at least 900 mm. When passing through bulkheads, this length shall be divided preferably into 450 mm on each side of the bulkhead. These ducts, or sleeves lining such ducts, shall be provided with fire insulation. The insulation shall have at least the same fire integrity as the bulkhead or deck through which the passes. Equivalent penetration protection shall be provided to the satisfaction of GL. B.2.3 Ducts with a cross-sectional area exceeding 0.075 m 2 , except those serving hazardous areas, shall be fitted with fire dampers in addition to meeting the requirements of B.2.2. The fire damper shall operate automatically but shall also be capable of being closed from both sides of the bulkhead or deck. The damper shall be provided with an indicator which shows whether the damper is open or closed. Fire dampers are not required, however, where ducts pass through spaces without serving these spaces, provided those ducts have the same fire integrity as the divisions which they pierce. GL may, given special considerations, permit operation from one side of a division only. B.2.4 A full cross-sectional area of a duct is to be considered for the above requirements. Splitting of ducts before the penetration and merging afterwards does not relax the requirements. B.3 Ventilation of machinery spaces, galleys and hazardous areas B.3.1 Ducts provided for the ventilation of machinery spaces of category "A", galleys and hazardous areas shall not pass through accommodation spaces, service spaces or control stations. However, GL may permit a relaxation from this requirement, except for the ducts serving hazardous areas provided that: B.3.2 Ducts are constructed of steel having a thickness of at least 3 mm for ducts of 300 mm in width or less and of at least 5 mm for ducts of 760 mm in width and over; in the case of ducts the width or diameter of which is between 300 mm and 760 mm, the thickness shall be obtained by interpolation. B.3.3 Ducts are fitted with automatic fire dampers close to the boundaries penetrated, and B.3.4 Ducts are insulated in "A-60" standard from the machinery spaces or galleys to a point at least 5 m beyond each fire damper. Or alternatively: B.3.5 Ducts are constructed of steel in accordance with B.3.2. B.3.6 Ducts are insulated to "A-60" standard throughout the accommodation spaces, service spaces or control stations. B.4 Ventilation of accommodation spaces, service spaces or control stations B.4.1 Ducts provided for the ventilation of accommodation spaces, service spaces or control stations shall not pass through machinery spaces of category A, galleys or hazardous areas. However, GL may permit a relaxation from this requirement, except for the ducts passing through hazardous areas, provided that: B.4.2 The ducts where they pass through a machinery space of category A or a galley are constructed of steel in accordance with B.3.2. B.4.3 Automatic fire dampers are fitted close to the boundaries penetrated. Edition 2013 Germanischer Lloyd Page 7–7
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(IV-7-3) General Safety

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