CEA 4001 - Annex E Special Requirements for High Rise Systems; Design criteria

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Annex E
Special Requirements for High Rise Systems
E.1 Scope
This Annex specifies requirements particular to the sprinkler protection of multi-storey buildings with
a height difference between the highest and lowest sprinkler exceeding 45m. The requirements are
applicable to buildings intended for use with occupancies where the hazard is classified as no greater
than Ordinary Hazard Group III.
NOTE: special fire engineering solutions are needed for high rise systems with hazards greater than OH3,
and
specialist advice should be sought.
E.2 Design criteria
E.2.1 Hazard group
High rise sprinkler systems shall comply with the requirements for Ordinary Hazard Group III protection.
E.2.2 Subdivision of high rise sprinkler systems
High rise sprinkler systems shall be sub-divided into sprinkler installations such that the height
difference between the highest and lowest sprinkler on any one installation does not exceed 45m
(see Figures El and E2).
E.2.3 Zoning
High Rise Sprinkler systems shall be zoned in accordance with Annex D.
E.2.4 Standing water pressures at back pressure and alarm valves
The minimum standing pressure at any back pressure or alarm valve inlet shall be no less than 1,25 times
the static head difference between the valve and the highest sprinkler on the installation.
Back pressure valves controlling installation flow should operate correctly with a ratio of service pressure to
installation
pressure not exceeding 1,16:1, as measured by valve lift and pressure equalisation upstream
of the back pressure valve.
E.2.5 Calculation of distribution pipework for pre-calculated systems
The main distribution pipes, including risers and drops, between the highest design point in an
installation and the zone subsidiary stop valve at the same floor level shall be sized by hydraulic
calculations. The maximum friction loss shall not exceed 0,5 bar at a flow of 1 000 l/min (see G. 2.4.2).
Where sprinkler protection is at various floor levels in an installation the allowable pressure loss between
the design points and zone subsidiary stop valves on lower levels, may be increased by an amount
equal to the difference in static head gain between the sprinklers at the level concerned and the
highest sprinkler in the installation.