BS 9251:2021 pdf download – Fire sprinkler systems for domestic and residential occupancies — Code of practice
COMMENTARY ON 5.4
BS 5306-0:2020, Clause 15 gives guidance on the use of sprinkler protection in the presence of electricalequipment and concludes it is generally safe to do so.
Sprinkler protection should be provided in all parts of the premises, however, sprinkler protectionmay be omitted from the following areas unless it is required by a fire strategy or risk assessment:NOTE Where a risk assessment is carried out,it needs to take into account presence of fuel load (e.g.linen),
presence of potential ignition sources (e.g. immersion heater) and consequence (e.g. impact upon fire protection tothe building or escape routes).
a) bathrooms and shower rooms with a floor area less than 5 m2 , with linings conforming to BSEN 13501-1:2018,Class A1,A2-s3, d2 and B-s3, d2, and which are not prepared for whitegoods, such as washing machines, dryers, electric showers or water heaters;
b) enclosed staircases containing only materials conforming to BS EN 13501-1:2018, Class B-s3 or better for construction materials and B(fl) or better for flooring, including sub categories such as d0, d1, d2 for construction materials and s1 and s2 for flooring, surface spread of flame andconstructed as a fire-resistant separation;
d)enclosed vertical shafts (e.g.lifts or service shafts) containing only materials conforming to
BS EN 13501-1:2018,Class B-s3 or better for construction materials and B(fl) or better for
flooring (including sub categories such as d0, d1, d2 for construction materials and s1 and s2 forflooring), surface spread of flame and constructed as a fire-resistant separation;
e) cupboards and pantries with a floor area of less than 2 m2 or where the least dimension does
not exceed 1 m which are not prepared for consumer units or electrical equipment ( excluding asingle light);
f)uninhabited loft /roof voids;
g)water closet (WC) with a floor area less than 5 m2, with linings conforming to
BS EN 13501-1:2018,Class A1,A2-s3, d2 and B-s3, d2, and which are not prepared for whitegoods,such as washing machines, dryers,electric showers or water heaters;
h) attached buildings, such as garages and plant rooms without direct access from within the
jexternal balconies permanently open to the outside.
5.5 Classification of residential and non-residential occupancies
COMMENTARY ON 5.5
Iln some parts of the building, residential sprinklers might not provide adequate protection.Therefore,the nature of occupancies needs to be determined and the type of sprinkler selected accordingly. Thisprocess could determine that some areas can be adequately protected with residential sprinklers(i.e. sprinkler heads conforming to BS EN 12259-14) and others require protection by so-called“commercial and industrial”sprinkler heads (i.e. sprinkler heads conforming to BS EN 12259-1).
Where limited areas of protection conforming to BS EN12845 design criteria (i.e.using sprinkler headsto BS EN 12259-1) are specified by this British Standard, the applicable design criteria are repeated inthis British Standard for ease of reference and are to be applied.It is not necessary to apply BS EN 12845in full unless more robust sprinkler protection in full conformity to that standard is specified.
ln all cases a hazard review should be carried out to determine the correct classification of occupancy.The recommendations in this subclause should be used to assist in selecting the correct design criteria for non-residential areas of a building which might require sprinkler protection usingsprinkler heads to BS EN 12259-1.
NOTE Examples of appropriate occupancies, design density and number of operation head areprovided in Table 3.
In no circumstances should the category of any area be less than that given in Table 2.All other non-residential areas should meet the recommendations of 5.6.
5.6Ordinary hazard protected areas
Where BS EN 12259-1 sprinkler heads are specified in 5.5 and Table 3 (by reference to Table 4), thefollowing parameters should be used:
a) the system should be a wet pipe system, with individually thermally actuated sprinkler heads;
b) full hydraulic calculation method should be used;
NOTE1 BS EN 12845 pre-calculation design method cannot be used.
c)a minimum design density of 5 mm/min should be applied;d) the area of operation should be in accordance with Table 4;
e)quick response heads conforming to BS EN 12259-1 should be used;
NOTE2 Recessed and concealed heads are not designated a thermal sensitivity rating.The standard thermalsensitivity test is not appropriate due to at least one of the following reasons:
1) the nature of the sprinkler assembly;
2) orientation of the sprinkler frame when installed; or
3) location of the temperature-sensitive element in relation to the roof or ceiling line.