A end centre array pipe array with range pipes on

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(a) end-centre array – pipe array with range pipes on both sides of a distribution pipe eg, 3 end-centre ( 3 sprinklers on each range pipe ) (b) end-side array – pipe array with range pipes on one side only of a distribution pipe eg, 2 end-side ( 2 sprinklers on each range pipe ) 35
2. The grid system – pipe array in which water flows to each sprinkler by more than one route 3. The looped system – pipe array in which there is more than one distribution pipe route along which water may flow to a range pipe 36
CLASSIFICATION OF OCCUPANCIES AND FIRE HAZARDS Light Hazard ( LH ) - according to clause 6.2.1 ( BS EN 12845 ) Ordinary Hazard ( OH ) – according to clause 6.2.2 (BS EN 12845 ) 37 ( BS EN 12845 )
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High Hazard ( HH ) High Hazard (HH ) is divided into two main classes : 1. High Hazard – Process ( HHP ) High Hazard – Storage ( HHS ) 41
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MAXIMUM AREA OF COVERAGE PER SPRINKLER 43
MINIMUM DISTANCE BETWEEN SPRINKLER AND WATER SHIELDS 44
DESIGN DENSITY OF SPRINKLER HEAD 45 It implies that the volume flow rate for each sprinkler head is 60 L/min for OH hazard class
WATER SUPPLY Water supply shall be capable of automatically furnishing at least the required pressure/flow conditions of the system. Each water supply shall have sufficient capacity for the following minimum duration : 46
The pressure and flow requirements for pre-calculated LH and OH system are specified in Table 6 below : 47
STORAGE TANK VOLUME FOR PRE-CALCULATED LH AND OH SYSTEMS 48
SPRINKLER TANK SIZE WITH INFILL FROM DOUBLE END FEED / DTL
DISTRIBUTION SYSTEM 17-Sep-20 PS & I 68
DISTRIBUTION SYSTEM 17-Sep-20 PS & I 69 Valve closed
CALCULATION OF INFLOW RATE TO FULFILL THE INFILL PERIOD As an example, for ordinary hazard group III installation with double end feed water supply, the sprinkler tank size is 75 m 3 , the nominal pump flow rate is 3100 l/m and the inflow rate can be calculated by the following formula : (௣௨௠௣ ௙௟௢௪ ௥௔௧௘ ௫଺଴ ୫୧୬) ି௧௔௡௞ ௩௢௟. ௜௡௙௟௢௪ ௣௘௥௜௢ௗ = ଷଵ଴଴௟ ̸ ௠ ௫ ଺଴ ି଻ହ ௖௨௕௜௖ ௠௘௧௘௥ ௫ ଵ଴଴଴ ଺଴ ௠௜௡ = ଵ଼଺଴଴଴ ି ଻ହ଴଴଴ ଺଴ = 1850 𝑙 ̸ m = ଵ଼ହ଴௟ ̸ ௠௜௡ ଺଴௦ = 30.8 𝑙 ̸ 𝑠 Therefore, the water main should be capable of delivering 30.8 l/s water to the sprinkler water tank when the sprinkler duty pump is drawing the max. water flow of 3100 l/min city main inflow rate = 1850 l/min sprinkler tank size = sprinkler duty pump nominal flow rate = 75000 l 3100 l/m
FOR REFERENCE ONLY For the same example, if the water supply flow rate from the water main is not adequate to meet the inflow rate of 1850 l/min or 30.8 l/s, transfer tank can be sized according to the following equation to provide some extent of buffer supply : [Actual city main supply flow rate(l/min) x infill period] + transfer tank size = transfer pump flow rate(l/min) x 60 min Hence, if the city main have a flow rate of 1100 l/min instead of 1850 l/min, Transfer tank size, l = transfer pump flow rate(l/min) x 60 min – [1100 x 60]l = [1850 x 60] - [1100 x 60] = 111000 – 66000 = 45000 l (45m 3 )
FOR REFERENCE ONLY city main inflow rate = 1100 l/min transfer tank size = transfer pump flow rate = 1850 l/m 45000 l sprinkler tank size = 75 m3

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