Description

Explains how to model foam-enhanced sprinkler, deluge and cannon systems in FHC to NFPA 11, covering proportioner pressure loss and water supply.

This technical data sheet (TDS) explains how to use Canute's FHC hydraulic calculation software for sprinkler, deluge or cannon systems enhanced with foam, based on NFPA 11: Standard for Low-, Medium-and High-Expansion Foam (2024 Edition) — which now incorporates the withdrawn NFPA 16.

Scope note: This TDS covers only the water and water/foam mix side of the system. It is not for calculating pressure loss in the foam concentrate line, which should be assessed against the manufacturer's own data.

It covers:

• Typical foam system components: pump, pipework, foam proportioner and foam output devices
• Using the Hazen-Williams pressure loss equation (as required by NFPA 13 for the water/foam side) with FHC's standard Fluid setting
• Entering pipework and output devices, including deriving a k-factor from a device's rated flow and pressure using FHC's +AF and +AB fields
• Running a first calculation and refining the design before adding the proportioner
• Adding the proportioner's pressure loss as a fixed pressure drop (PD - bars) once its flow-dependent loss is known from the manufacturer's data
• Balancing the system to a water supply curve to find the system's maximum flow demand (Qmax), and re-checking the proportioner loss afterwards since the flow rate will have increased

See the Hazen-Williams equation explained for background on the pressure loss formula used here, or view the FHC product page. This TDS refers to TDS4 for adding a water supply curve to an FHC project.

Issue 2 (July 25) Updated to incorporate NFPA 11 requirements.