The shape and composition of the piping network of sprinklers
The sprinkler piping network can be implemented in 3 ways, the choice of each of them is made by considering the condition of the building, the conditions of water sources, the place of its entry into the building, etc.
The 3 mentioned methods are:
A – Cross or Tree method
B- Looped method
C – Gridded network method
Shape and composition of the sprinkler piping network:
For a better understanding of the above methods, let’s define the components of the sprinkler piping network:
A – Riser
A vertical pipe that moves water vertically.
B- Branch Line
The pipe branch on which the sprinklers are installed.
C – Cross Main
The main pipe that is connected to the branches and delivers water through the riser to the branches and then to the sprinklers.
D – Feed Main
It is a pipe that is considered as the main feeder of the riser.
Cross or tree sprinkler systems
In this system, the branches are only connected to the Cross pipe and have no connection with each other, and there is only one path to supply water to the sprinklers. This system can be implemented in four ways:
1- Center feeding – center 3- Side feeding – center
2- Center-end feeding 4- Side-end feeding
Ring systems of sprinkler networks
In this system, there are two paths for supplying water to the sprinklers. In this method, the ends of the Cross pipes are connected to each other and the branches are connected to them. In this system, the branches are not related to each other.
Sprinkler network systems
In this system, due to the existence of several paths for supplying water to the sprinklers, and as a result, dividing the flow in each path and reducing the pressure drop caused by friction, they have the highest efficiency. Cross are connected to each other through branches.
Determining the size of pipes
The size of pipes in sprinkler systems is determined using the following 2 methods:
A – Existing situation method using predefined Pipe Schedule tables
B – Hydraulic Calculation method
Using the method of predetermined tables
Pipe Schedule
In this method, the diameter of each part of the pipe is determined based on the number of installed sprinklers according to the table below.
Table number one – Pipe size determination based on the number of sprinklers for a low risk environment
Important: It should be noted that using the Pipe Schedule method is possible only in the following conditions:
1- The maximum covered area for calculation using the above method is 5,000 square feet, although if 50 PSI pressure is provided in the farthest sprinkler, it is possible to install in more areas.
2- Making changes by adding to the existing system in high-risk environments
3- Only sprinklers with K=5.6 factor.
4- Use of metal pipes.
5- Low risk or medium risk environments.
6- Installing a maximum of 8 sprinklers in each branch (up to 10 sprinklers in each branch is allowed in special conditions).
7- It cannot be used outdoors and only for indoor use.
Using the hydraulic calculation method to determine the diameter of sprinkler network pipes
In this method, according to the relations and formulas of fluid mechanics, the diameter of the pipe is determined based on the supply of pressure and flow rates. If computer software is used, hydraulic calculations are done with high speed and accuracy.
