Design of Sprinkler System

Client: M/s. Prestige Estates Projects Ltd., Bangalore

Project: Prestige Technopolis, Bangalore

Design of Flow and pressure required for Sprinkler System: The pump capacity is calculated. As per IS15105, Table: 10, Page-15, minimum pressure required at sprinkler point for light hazard sprinkler is 2.2bars. Assumed area of Maximum Operation for Light hazard as per IS Design density = 2.25LPM/M2 and AMAO= 84 M2 (Assumed area of operation for the remote point) Discharge for the demand area = 2.25 x 84 = 189lpm Required pump capacity = 189lpm Proposed Pump capacity 2850 lpm (a)

Pressure loss calculations:

Considering the above pump head shall be 2.0 bar + pressure loss through the pipes / fittings /valves till the Alarm valve and the static head (height difference). The same is calculated by using Hazen – William’s formula as under. P=

6.05 X 105 x L x Q1.85 C1.85 x D 4.87

Where P = Loss of pressure per meter length of pipe in bar Q = Flow rate through the pipe in LPM D = Dia of the pipe used in mm C = Constant for type of pipe used i.e., G.I. Heavy grade. L = Equivalent length of pipes, Fittings and valves Section – I: Friction loss through sprinkler pipe from pump room to the shaft riser Length of Sprinkler Pipe of 150mm dia from pump room to the shaft riser Terminal main = 170m (a) Pressure loss through 150 mm dia Terminal main pipe P1 =

6.05 X 105 x 170 x 28501.85 1201.85 x 150 4.87

P1 = 0.91bar

Date: 11.02.2014

1

PHE & Firefighting Consultants: M/s. Sampath Kumar Associates Pvt Ltd, Bangalore

Client: M/s. Prestige Estates Projects Ltd., Bangalore

Project: Prestige Technopolis, Bangalore

Section – II: Friction loss through sprinkler riser inside building shaft Pipe size considered is 100mm dia for sprinkler riser, connected branch pipes = 10m (a) Pressure loss through 100 mm dia sprinkler riser P2 =

6.05 X 105 x 10 x 28501.85 1201.85 x 100 4.87

P2 = 0.40 bar Section – III: Friction loss through sprinkler Branch main inside building Pipe size considered is 50 mm dia for Branch main = 5m Discharge for the demand area = 189lpm Design density AMAO = 84Sq.m Sprinkler coverage for light hazard = 21sq.m/sprinkler Discharge per sprinkler = (189/84)*21 = 47.50LPM, Say 48LPM (a) Pressure loss through 50mm dia terminal main pipe connected to 8 Nos sprinklers Flow in three sprinklers = 8 x 48lpm = 384lpm P3 =

6.05 X 105 x 5 x 3841.85 1201.85 x 50 4.87

P3= 0.14bar Section – IV: Friction loss through sprinkler Branch main inside building Pipe size considered is 32mm dia for Branch main = 3m (a) Pressure loss through 32mm dia terminal main pipe connected to 3Nos sprinklers Flow in three sprinklers = 3 x 48lpm = 144lpm P4 =

6.05 X 105 x 3 x 1441.85 1201.85 x 32 4.87

P4 = 0.11 bar

Date: 11.02.2014

2

PHE & Firefighting Consultants: M/s. Sampath Kumar Associates Pvt Ltd, Bangalore

Client: M/s. Prestige Estates Projects Ltd., Bangalore

Project: Prestige Technopolis, Bangalore

Section – V: Friction loss through sprinkler Branch main inside Building Pipe size considered is 25mm dia for Branch main = 3m (a) Pressure loss through 25mm dia terminal main pipe connected to 2Nos sprinklers Flow in two sprinklers = 2 x 48lpm = 96lpm 6.05 X 105 x 3 x 961.85 1201.85 x 25 4.87

P5 =

P5 = 0.18 bar Section – VI: Friction loss through sprinkler Branch main inside Building Pipe size considered is 25mm dia for Branch main = 3m (a) Pressure loss through 25mm dia terminal main pipe connected to 1No sprinkler P=

6.05 X 105 x 3 x 481.85 1201.85 x 25 4.87

P6 = 0.05 bar Total Frictional loss = P1 + P2 + P3 + P4 + P5 + P6 = 0.91 + 0.4 + 0.14 + 0.11 + 0.18 + 0.05 = 1.79 Bar Add 10% Extra for fittings, specials and valves etc., = 1.79 x 1.1 = 1.97 Bar Total Head = Suction head + Static head + Frictional loss + Residual Head Available residual head = Total Head – (Static head + Frictional loss) = 11.0 - (0.8+1.97) = 8.23bar

Required Residual pressure for farthest sprinkler is 2.2 Bar and the available pressure at remote sprinkler would be 8.23 Bar in the Sprinkler Pipe line, therefore dia of ring main and the flow of the system in line with the design requirements, proposed pump capacity and pipe line dia are sufficient for the proposed building, hence Design is adequate . NOTE: For dwg pls refer dwg no. FF-02 & FF-04 of sprinkler system

Date: 11.02.2014

3

PHE & Firefighting Consultants: M/s. Sampath Kumar Associates Pvt Ltd, Bangalore