Section 2 Definitions
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 7 Safety Systems, Hazardous Areas and Fire - Chapter 3 Fire Safety - Section 2 Definitions

Section 2 Definitions

Parent topic: Chapter 3 Fire Safety

2.1 Materials

2.1.1  Non-combustible material means a material which neither burns nor gives off flammable vapours in sufficient quantity for self-ignition when heated to approximately 750°C, according to an acceptable test procedure (see 2010 FTP Code – International Code for Application of Fire Test Procedures, 20101 – Resolution MSC.307(88). Any other material is a ‘combustible material’.

2.1.2  Steel or other equivalent material. Where the words ‘steel or other equivalent material’ occur, ‘equivalent material’ means any non-combustible material which, by itself, or due to insulation provided, has structural and integrity properties equivalent to steel at the end of the applicable fire exposure to the standard fire test (e.g. aluminium with appropriate insulation).

2.2 Fire test

2.2.1 A standard fire test is one in which specimens of the relevant bulkheads or decks are exposed in a test furnace to temperatures corresponding approximately to the standard time-temperature curve. The specimen is to have an exposed surface of not less than 4,65 m2 and height (or length of deck) of 2,44 m resembling as closely as possible the intended construction and including where appropriate at least one joint. The standard time-temperature curve is defined by a smooth curve drawn through the following temperature points measured above the initial furnace temperature:
at the end of the first 5 minutes 576°C
at the end of the first 10 minutes 679°C
at the end of the first 15 minutes 738°C
at the end of the first 30 minutes 841°C
at the end of the first 60 minutes 945°C
2.2.2 A hydrocarbon fire test is one in which the specimens defined for a standard fire test are exposed in a test furnace to temperatures corresponding approximately to a time temperature curve relating to, and defined by, a smooth curve drawn through the following temperature points measured above the initial furnace temperature:
at the end of the first 3 minutes 880°C
at the end of the first 5 minutes 945°C
at the end of the first 10 minutes 1032°C
at the end of the first 15 minutes 1071°C
at the end of the first 30 minutes 1098°C
at the end of the first 60 minutes 1100°C

2.2.3 A jet-fire test is used to determine how effective the passive fire protection materials are in withstanding an actual jet fire. Reference should be made to ISO 22899-1 with regard to jet-fire testing arrangements and defined jet-fire ratings.

2.3 Flame spread

2.3.1  Low flame spread means that the surface thus described will adequately restrict the spread of flame, having regard to the risk of fire in the spaces concerned, this being determined by an acceptable test procedure (see 2010 FTP Code – International Code for Application of Fire Test Procedures, 20101 – Resolution MSC.307(88).

2.4 Fire and Explosion Evaluation (FEE)

2.4.1 The FEE is an assessment of the potential fire loadings and blast pressures, based on the specific hazards associated with the general layout of the unit, production and process activities and operational constraints.

2.4.2 These Rules allow for the dimensioning of explosion loads to be based on probabilistic risk assessment techniques. A methodology to establish risk-based explosion loads based on such a probabilistic approach is given in LR's Guidance Notes for the Calculation of Probabilistic Explosion Loads.

2.4.3 Important parts of the FEE are the types of fires likely to occur on the offshore unit, the dimensioning of fire loads, fire protection principles, fire mitigation measures and fire response. To assist in developing the FEE, information covering these aspects are provided in LR's Guidance Notes for Fire Loadings and Protection.

2.5 Temporary refuge

2.5.1 This is a designated area that is to provide adequate facilities to protect the personnel from fire, explosion and associated hazards during the period for which they may need to remain on a unit following an uncontrolled incident, and for enabling their evacuation, escape and rescue. It is also to provide adequate facilities for monitoring and control of any major incident.

2.6 Fire divisions, spaces and equipment

2.6.1  ‘A’ Class divisions are those divisions formed by bulkheads and decks which comply with the following:
  1. They are to be constructed of steel or other equivalent material.
  2. They are to be suitably stiffened.
  3. They are to be so constructed as to be capable of preventing the passage of smoke and flame up to the end of the one-hour standard fire test.
  4. They are to be insulated with approved noncombustible materials such that the average temperature of the unexposed side will not rise more than 140°C above the original temperature, nor will the temperature, at any one point, including any joint, rise more than 180°C above the original temperature, within the time listed below:
    Class ‘A–60’ 60 minutes
    Class ‘A–30’ 30 minutes
    Class ‘A–15’ 15 minutes
    Class ‘A–0’ 0 minutes.
  5. A test of a prototype bulkhead or deck may be required to ensure that it meets the above requirements for integrity and temperature rise.

    Such divisions may be faced with combustible materials, facings, mouldings, decorations and veneers, provided those are in accordance with the requirements of 3.2 Use of combustible materials.

2.6.2  ‘H’ Class divisions are those divisions formed by fire walls and decks which comply with the construction and integrity requirements for ‘A’ Class divisions, Pt 7, Ch 3, 2.6 Fire divisions, spaces and equipment 2.6.1.(a) and Pt 7, Ch 3, 2.6 Fire divisions, spaces and equipment 2.6.1.(b) and with the following:
  1. They are to be so constructed as to be capable of preventing the passage of smoke and flame up to the end of the one-hour hydrocarbon fire test. (Note that some administrations may require the ‘H’ Class division integrity to be maintained for 120 minutes).
  2. They are to be insulated with approved noncombustible materials, such that the average temperature, on the unexposed side, when exposed to a hydrocarbon fire test, will not rise more than 140°C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 180°C above the original temperature within the time listed below:
    Class ‘H–120’ 120 minutes
    Class ‘H–60’ 60 minutes
    Class ‘H–0’ 0 minutes
  3. A test of a prototype fire wall or deck may be required to ensure that it meets the above requirements for integrity and temperature rise.
2.6.3  ‘B’ Class divisions are those divisions formed by bulkheads, decks, ceilings or linings which comply with the following:
  1. They are to be so constructed as to be capable of preventing the passage of flame to the end of the first half hour of the standard fire test.
  2. They are to have an insulation value such that the average temperature of the unexposed side will not rise more than 140°C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 225°C above the original temperature, within the time listed below:
    Class ‘B–15’ 15 minutes
    Class ‘B–0’ 0 minutes
  3. They are to be constructed of approved noncombustible materials and all materials entering into the construction and erection of ‘B’ Class divisions are to be non-combustible.
  4. A test of a prototype division may be required to ensure that it meets the above requirements for integrity and temperature rise.

    Such divisions may be faced with combustible materials, facings, mouldings, decorations and veneers, provided those are in accordance with the requirements of Chapter II-2 - Construction - Fire protection, fire detection and fire extinction.

2.6.4  ‘C’ Class divisions are divisions to be constructed of approved non-combustible materials. They need meet neither requirements relative to the passage of smoke and flame, nor limitations relative to the temperature rise. Such divisions may be faced with combustible materials, facings, mouldings, decorations and veneers, provided those are in accordance with the requirements of Chapter II-2 - Construction - Fire protection, fire detection and fire extinction.

2.6.5  Continuous ‘B’ Class ceilings or linings are those ‘B’ Class ceilings or linings which terminate only at an ‘A’ or ‘B’ Class division. Such linings and ceilings may be faced with combustible materials, facings, mouldings, decorations and veneers, provided those are in accordance with the requirements of Chapter II-2 - Construction - Fire protection, fire detection and fire extinction.

2.6.6  Machinery spaces of Category ‘A’ are those spaces and trunks to such spaces which contain:
  1. Internal combustion machinery used for main propulsion; or
  2. Internal combustion machinery used for purposes other than main propulsion where such machinery has in the aggregate a total power output of not less than 375 kW; or
  3. Any oil-fired boiler or fuel oil unit.

2.6.7  Machinery spaces are all machinery spaces of Category ‘A’ and all other spaces containing propelling machinery, boilers, fuel oil units, steam and internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilising, ventilation and air conditioning machinery, and similar spaces, and trunks to such spaces.

2.6.8  Control stations are those spaces in which the unit’s radio or main navigating equipment is located or where the fire-control equipment or the dynamic positioning control system is centralised or process control equipment or where a fire-extinguishing system serving various locations is situated or, in the case of column-stabilised units, a centralised ballast control station is situated.

2.6.9 For definitions and categories of hazardous areas including ‘enclosed’ and ‘semi-enclosed’ spaces, see Pt 7, Ch 2, 1.2 Definitions and categories.

2.6.10  Drilling and process plant and industrial machinery and components are the machinery and components which are used in connection with the operation of drilling, production and process systems.

2.6.11  Working spaces are those open or enclosed spaces containing equipment and processes which are not included in Pt 7, Ch 3, 2.6 Fire divisions, spaces and equipment 2.6.6 or Pt 7, Ch 3, 2.6 Fire divisions, spaces and equipment 2.6.7

2.6.12  Accommodation spaces are those used for public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, pantries containing no cooking appliances and similar spaces. ‘Public spaces’ are those portions of the accommodation which are used for halls, dining rooms, lounges and similar permanently enclosed spaces.

2.6.13  Service spaces are those used for galleys, pantries containing cooking appliances, lockers and storerooms, workshops other than those forming part of the machinery spaces, and similar spaces and trunks to such spaces.

2.6.14  Fuel oil unit is the equipment used for the preparation of fuel oil for delivery to an oil-fired boiler, or equipment used for the preparation for delivery of heated oil to an internal combustion engine, and includes any oil pressure pumps, filters and heaters dealing with oil at a pressure of more than 1,8 bar.

2.6.15  Crude oil is any oil occurring naturally in the earth whether or not treated to render it suitable for transportation and includes:
  1. Crude oil from which certain distillate fractions may have been removed; and
  2. Crude oil to which certain distillate fractions may have been added.

2.6.16  Storage spaces are spaces used for bulk storage and trunks to such spaces, e.g. crude oil storage tanks on oil storage units.

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