Section 5 Deckhouses and superstructures used for accommodation, ‘temporary refuge’ or ‘alternative/secondary refuge or shelter’

5.1.1 Particular consideration is to be given to the potential effects of fire and blast, as determined in the unit’s ‘Fire and Explosion Evaluation’ (FEE) report required by Pt 7, Ch 3, 1.2 Submission of documentation 1.2.4, impinging on exposed boundary bulkheads of accommodation spaces, ‘temporary refuge’ or ‘alternative/secondary refuge or shelter’. Where boundary bulkheads can be subjected to blast loading the scantlings are to comply with Pt 4, Ch 3, 4.16 Accidental loads 4.16.8 and Pt 4, Ch 4, 1.10 Topside structure.

5.2.1 In addition to the requirements of Pt 7, Ch 2, 4 Enclosed and semi-enclosed spaces with access to a hazardous area, enclosed spaces of deckhouses and superstructures used for accommodation and/or ‘temporary refuge’ or ‘alternative/secondary refuge or shelter’ are to be at an overpressure relative to the external area to prevent the potential ingress of smoke and hazardous gases, in the event of a major topsides incident.

5.2.2 With reference to Pt 7, Ch 3, 5.2 Safety critical requirements for enclosed spaces 5.2.1, the design of the accommodation, 'temporary refuge' and ‘alternative/ secondary refuge or shelter’ is to be such that their enclosures are supplied with a ventilation system designed to maintain an overpressure of at least 50 Pa in relation to adjacent external spaces. The ventilation air intakes to any such enclosure are to be equipped with suitable hydrocarbon gas, smoke and/or toxic gas detection, dependent upon the credible risks associated with the installation or unit. The enclosures are to be constructed with suitable fire-rated and gastight barriers, suitable fire-rated and gastight doors, and suitable fire-rated and gas-rated dampers. The design of the enclosures is to be such that, on hydrocarbon gas, smoke and/or toxic gas detection at the enclosure ventilation air intakes, dependent upon the credible risks associated with the installation or unit, the enclosure ventilation system will shut down and all ventilation fire and gas dampers will close in order to mitigate against potential hydrocarbon gas, smoke and/or toxic gas entering the accommodation, 'temporary refuge' or ‘alternative/secondary refuge or shelter’. Dependent upon the design of the accommodation, ‘temporary refuge’ or ‘alternative/secondary refuge or shelter’ ventilation system, consideration should be given to retain a recirculation ventilation system or an alternative air supply to such enclosures on hydrocarbon gas, smoke and or/toxic gas detection at the enclosure ventilation air intakes. However, it should be ensured that the integrity of the enclosures is not impaired by continued operation of any ventilation system in this scenario.

Design of the ‘temporary refuge’ has also to ensure an appropriate environment for personnel mustering at the location, and for that purpose consideration should be given to criteria such as oxygen depletion, CO2 build-up and temperature build-up. Information relevant to any such system can be provided as part of the ‘Escape, Evacuation and Rescue Assessment’ (EERA) required by Pt 7, Ch 3, 1.2 Submission of documentation 1.2.4.

5.2.4 With reference to Pt 7, Ch 3, 5.2 Safety critical requirements for enclosed spaces 5.2.2, the design of the accommodation ‘temporary refuge' or ‘alternative/secondary refuge or shelter’ enclosure is to include a suitable air leakage rate to mitigate against any potential hydrocarbon gas, smoke and/or toxic gas impairment on isolation of the accommodation, ‘temporary refuge’ or ‘alternative/secondary refuge or shelter’ enclosure ventilation. The air leakage rate should be based on the required endurance period of the accommodation, 'temporary refuge' or ‘alternative/secondary refuge or shelter’ in any potential credible hydrocarbon gas, smoke and/or toxic gas incident associated with the installation or unit.

5.2.5 When the escape, evacuation and rescue philosophy for the installation or unit, or the ‘Escape, Evacuation and Rescue Assessment’ (EERA), referred to in Pt 7, Ch 3, 1.2 Submission of documentation 1.2.4, require an alternative or a secondary refuge/shelter, it should be demonstrated that any such refuge/shelter provides appropriate levels of protection and evacuation facilities (including personal protective equipment and personal lifesaving appliances, as applicable) for personnel mustering at those locations, as defined in the EERA.

5.3.1 Access doors to spaces referred in Pt 7, Ch 3, 5.2 Safety critical requirements for enclosed spaces 5.2.1 are to be fitted with self-closing gastight doors that open outwards from the enclosed space. Special consideration will be given to spaces which are protected by mechanically ventilated air locks, see also Pt 7, Ch 2, 4 Enclosed and semi-enclosed spaces with access to a hazardous area.