Ventilation systems for machinery spaces of category A, galleys, and hazardous areas are to be separated from each other and from the ventilation systems serving other spaces, (see also 4-3-6/7.1). Ducts provided for ventilation of machinery spaces of Category A, hazardous areas. and galleys are not to pass through accommodation and service spaces or control stations. However, some relaxation from this requirement (except for the ducts serving hazardous areas and passing through accommodation spaces, control stations, and galleys) will be considered, provided that the ducts are: i) Constructed of steel at least 3 mm (0.12 in.) thick for ducts 300 mm (12 in.) wide or less, and at least 5 mm (0.20 in.) for ducts 760 mm (30 in.) wide and over. The minimum thickness is to be interpolated for widths or diameters between 300 and 760 mm (12 and 30 in.); ii) Fitted with an automatic fire damper close to the boundaries penetrated; iii) Insulated to “A-60” standard from the machinery space or galleys to a point at least 5 m (16.4 ft) beyond each fire damper; and iv) The ducts are to be suitably supported and stiffened; or v) Constructed of steel in accordance with 5-1-1/5.29i) and 5-1-1/5.29iv) above; and vi) Insulated to “A-60” standard throughout the accommodation spaces, service spaces or control stations.
综上所述不必考虑先后顺序只要 ii) Fitted with an automatic fire damper close to the boundaries penetrated; 就好了
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