AUTOMATIC FIRE SPRINKLER SYSTEM DESIGN
Content
1) Classification of Occupancy
2) Water Supply/Storage Requirement
3) Sprinkler Spacing, Rating & Coverage
4) Piping Layout
5) Hydraulic Calculation
6) Pump Selection
Automatic Fire Sprinkler System
Content
1) Classification of Occupancy
2) Water Supply/Storage Requirement
3) Sprinkler Spacing, Rating & Coverage
4) Piping Layout
5) Hydraulic Calculation
6) Pump Selection
Automatic Fire Sprinkler System
After the Architect has confirmed whether or not a building requires an automatic fire
protection system, the engineer must determine the appropriate Hazard Group
Classification.
The Hazard Group Classifications are, in order of risk from Low to High.
Light Hazard Occupancy
Ordinary Hazard Occupancy – Group I
Ordinary Hazard Occupancy – Group I
Ordinary Hazard Occupancy – Group II
Ordinary Hazard Occupancy – Group III
Ordinary Hazard Occupancy – Group III Special
High Hazard Occupancy
High Hazard Occupancy– Process Risks
High Hazard Occupancy – High Piled Storage Risks
Classification of Hazard Group
Classification of Hazard Group
Determine Hazard GroupThe Hazard Group Classification is a measure of the likely relative severity of a fire based on
the occupancy of the space. Spaces with different occupancy types may have different hazard
group classifications.
Example – MazdaOccupancy of space includes,
- Office - (OH 1) , clause 3.2.3.1
- Motor garages, including public and private car park- (OH 2) , clause 3.2.3.2
- Showroom - (OH 3) , clause 3.2.3.3
- Painting (Spray booth) - (HH, Process risk / Cat 3) , clause 3.2.4.1
Classification of Hazard Group
Determine Hazard Group
Example – Mazda Occupancy of space includes,
- Office - (OH 1) , clause 3.2.3.1
- Motor garages, including public and private car park- (OH 2) , clause 3.2.3.2
- Showroom - (OH 3) , clause 3.2.3.3
- Painting (Spray booth) - (HH, Process risk / Cat 3) , clause 3.2.4.1
Content
1) Classification of Occupancy
2) Water Supply/Storage Requirement
3) Sprinkler Spacing
4) Piping Layout
5) Hydraulic Calculation
6) Pump Selection
Automatic Fire Sprinkler System
Water Supply/Storage Requirement
Based on Hazard group to determine Minimum Capacity Water Storage
Storage requirement with Calculated design flow rate with Automatic inflow (900
L/min)
a) 30 mins for LH plus 1.3 time (clause 13.8.2.3)
b) 60 mins for OH and,
c) 90 mins for HH.
- Notes: Water supplies to sprinkler systems require a high level of reliability. Deem no
reliable source of Town water supply.
Minimum capacity of water supplies
a) Table 16 for Ordinary Hazard (Sprinkler & Hose reel)
b) Table 24 for High Hazard
Water Supply/Storage Requirement
Example – Mazda for Water Storage Tank
There having several occupancy groups. Occupancy of space includes,
- Office - (OH 1) , clause 3.2.3.1
- Motor garages, including public and private car park- (OH 2) , clause 3.2.3.2
- Showroom - (OH 3) , clause 3.2.3.3
- Painting (Spray booth) - (HH, Process risk / Cat 3) , clause 3.2.4.1.
The water supply must be capable of meeting the most hydraulically demanding area of the
systems. (NFPA 13 – Water Supply).
Water Supply/Storage Requirement
Example – Mazda for Water Storage Tank There may chose with many options for minimum storage capacity.
In Myanmar, automatic inflow form Town water supply is still yet to improve
The calculation of water storage capacity with design flow rate is only suitable for
Light Hazard Occupancies.
The Ordinary and High Hazard recommend to use as per CP 52, Table 16 for
Ordinary Hazard and Table 24 for High Hazard.
Water Supply/Storage Requirement
Water Storage Capacity for Ordinary Hazard
Water Supply/Storage Requirement
Water Storage Capacity for Ordinary Hazard
Maxi Height of spk is about 15 m @ 135 000 L ,or 135 m3
Water Supply/Storage Requirement
Water Storage Capacity for High Hazard
Water Supply/Storage Requirement
Water Storage Capacity for High Hazard
Water Supply/Storage Requirement
Water Storage Capacity for High Hazard
Density of Discharge is 7.5 mm/mm @ 237 000 L or 237
m3
Water Supply/Storage Requirement
Example – Mazda for Water Storage Tank Design Data for Spray booth (Mazda)
Occupancy - Paint and varnish works (solvent based)
Design Density – 7.5 mm/min (Table 20)
Calculate Minimum Water Storage) Option1, (From Table 23, 2nd column) )
2300 L/min x 90 min = 207 000 Liters or 207 m3 or,
237 000 Liters or 237 m3
Calculate Minimum Water Storage Option 2, with Area x Density of discharge
Spray booth area – 47 m2
Density of Discharge - 7.5 mm/min
Minimum flow for Sprinklers – 325.5 L/min
Minimum storage to be maintained – 90 min
Minimum storage capacity – 325.5 x 90 = 31725 Liters or 31.73 m3
Water Supply/Storage Requirement
Example – Mazda for Water Storage Tank
Determine the Minimum Water Storage Capacity From Pump Flow with OH3 (15 m), if ignore HH for spray boot
1350 L/min x 60 min = 81 000 Liters or 81 m3
From Table 16 & 24
135 000 Liters or 135 m3 with OH3 (15 m) Hazard if ignore HH for spray boot
237 000 Liters or 237 m3 with High Hazard
Water Supply/Storage Requirement
Example – Mazda for Water Storage Tank
Determine the Minimum Water Storage Capacity From Pump Flow with OH3 (15 m), if ignore HH for spray boot
1350 L/min x 60 min = 81 000 Liters or 81 m3
From Table 16 & 24
135 000 Liters or 135 m3 with OH3 (15 m) Hazard if ignore HH for spray boot
237 000 Liters or 237 m3 with High Hazard
Content
1) Classification of Occupancy
2) Water Supply/Storage Requirement
3) Sprinkler Spacing, Rating & Coverage
4) Piping Layout
5) Hydraulic Calculation
6) Pump Selection
Automatic Fire Sprinkler System
Sprinkler Spacing, Rating & Coverage
Light Hazard (LH)a) Criteria
Assumed area of operation – 84m²
Design density – 2.25mm/min
Max. coverage per sprinkler
- Sidewall – 17m2
- Other sprinklers – 21m²
b) Max distance between sprinkler
Sidewall – 4.6m
Other sprinklers – 4.6m
Size of sprinkler – 10mm
c. Max distance from wall or partition
Sidewall sprinklers from end walls – 2.3m
Other sprinklers – 2.3m
Sprinkler Spacing, Rating & Coverage
Ordinary Hazard (OH)a) Criteria
Assumed area of operation
- Group I – 72m², Group II – 144m², Group III – 216m² , Group III S – 360m²
Design density
- 5mm/min
Max. coverage per sprinkler
- Sidewall – 9m2
- Other sprinklers – 12m²
b) Max distance between Sprinklers
Sidewall – 3.7m
Other sprinklers
Spacing between rows – 4.2m
- Standard spacing– 4.2m
- Staggered spacing – 4.6 m
- Size of sprinkler – 15mm
Sprinkler Spacing, Rating & Coverage
High Hazard (OH)a) Criteria
Process Risks
- Assumed area of operation – 260m²
- Design density – 7.5mm/min to 12.5mm/min
High Piled Storage Risks
- Assumed area of operation – 260m² to 300m²
- Design density – 7.5mm/min to 12.5mm/min
Max. coverage per sprinkler – 9m² (except rack sprinklers)
b) Max. distance between sprinklers – 3.7m
Size of sprinklers
- 15mm
- 20mm
Content
1) Classification of Occupancy
2) Water Supply/Storage Requirement
3) Sprinkler Spacing, Rating & Coverage
4) Piping Layout
5) Hydraulic Calculation
6) Pump Selection
Classification of Hazard Group
Hydraulic Calculation
Design Points Sprinkler design points are the hydraulic most demanding point(s) in the sprinkler system immediately
prior to the group of heads that are required to discharge.
These are the points for which the system inlet pressure and distribution pipe sizing must be designed to
provide adequate water pressure at the sprinkler heads.
The design points are typically at the most remote ends of any sprinkler array.
The design numbers of heads to discharge are as follows:
a) LH – after 6 sprinklers
Flow rate – 48 L/min per spk
Minimum discharge pressure – 70 kPa
b) OH – after 16/18 sprinklers
Flow rate – 70 L/min per spk (or),
Minimum discharge pressure – 35 kPa
Full flow at 1800 L/min and fiction loss shall not exceed 150 kPa (including main distribution
pipe and all risers)
c) HH – depends on area of operation. Refer to CP 52 Table 20.
Minimum discharge pressure – 50 kPa
Hydraulic Calculation
Hydraulic Calculations and Pipe Sizing• Full hydraulic calculations are required for LH & HH systems.
• Partial hydraulic calculations are permissible for OH systems.
• Hydraulic calculations are required for sprinkler systems to confirm:
• The pressure drop from Control Valve to the Design Point in order to size the Fire Pump and size the
distribution pipework.
• The pressure drop from Pump to Control valve to confirm pressure at CV is not less than that
specified in CP52.
• To determine the pressure that will occur in sprinkler pipework branches closer to the pump and
assess if excess sprinkler flow may be a difficulty.
Hydraulic Calculation
Pre Hydraulic calculation
This friction loss from CV to DPs may not exceed 150 kPa based on design flow rate of
1800 L/m as specify by code.
Pressure drop from 90 ° bend is equivalent to 3m pipe length.
Sprinkler Pump Head
The pump head required is the sum of the pressure drop from the pump suction to
the sprinkler CV plus the minimum head specified in CP 52 Table 5.
Hydraulic Calculation
Pump Head Requirement The pump head required is the sum of the pressure drop from the pump suction to the sprinkler CV
plus the minimum head specified in CP 52 Table 5.
Hydraulic Calculation
Pump Head Requirement
Hydraulic Calculation
Pump Head Requirement