6.6 Step Six - Design Piping System Layout
Lay out the piping system for the sprinklers using either a gridded,
looped or straight-run con
fi
guration as de
fi
ned by NFPA 13D.
6.6.1 Connections to Domestic Cold Water Plumbing Systems
fi
ttings can be installed in the main sprinkler piping lines
to allow for connection to the plumbing
fi
xtures. Connections to the
system that are only supplying plumbing
fi
xtures are required by
NFPA 13D to meet local plumbing codes. RAUPEX UV shield pipe and
fi
ttings meet all requirements for domestic plumbing
applications.
Fig. 6.2: Domestic cold water plumbing connection
6.7 Step Seven - Perform Hydraulic Calculations to Verify
System Performance
Hydraulic calculations must be performed to verify that the system is
sized properly to achieve the
fl
ow and pressure required for proper
sprinkler operation. Calculations must be performed using an
approved
fi
re sprinkler design method in accordance with local
requirements.
Hydraulic calculations are typically done by starting with the
fl
ow and
pressure demand for the most hydraulically demanding point in the
system for both one-head activation and two-head activation. The
most hydraulically demanding point in the system is usually the
sprinkler most distant from the water supply.
The calculations must show that the pressure and
fl
ow available at
the street is adequate to provide the required
fl
ow and pressure to the
sprinklers with one- and two-head
fl
ow scenarios.
If the calculations do not show that adequate
fl
ow and pressure is
available, modi
fi
cations to the piping system can be made in an
attempt to meet the requirements of the system. These modi
fi
cations
include:
- Reducing the coverage area of the sprinklers thus possibly reducing
the required
fl
ow or pressure at each head
- Increasing the size of the service main
- Adding a piping loop to the system
- Upsizing the piping in the system from 3/4 to 1 in.
If the calculations still do not show adequate
fl
ow and pressure is
available for proper system operation, consideration for a pressure
booster system with optional storage capacity may be necessary.
6.8 Step Eight - Obtain AHJ Approval
Once the complete system is designed and properly calculated,
fi
nal
approval from the local authority having jurisdiction must be obtained
prior to installation.
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