FHC Project Examples

ESFR fire sprinkler installation is installed in major car manufacturers’ parts facilities and is somewhat bespoke in its design. The roof level sprinklers are ESFR 25mm with a K-factor of 360 and a minimum head pressure of 3.5 bars. In addition, the rack storage below is protected with a 20mm sprinkler with a K-factor of 115 and a minimum head pressure of 1.0 bar. The final water demand requirements for the system were 9849 L/min @ 9.0 bar, and the design, aided by FHC, achieved 98% design efficiency.

This FHC hydraulic model consisted of 810 pipes, 154 loops and 26 heads. It was calculated on a Pentium VI computer in under 0.1 seconds.

An FHC hydraulic calculation that demonstrates its capabilities and shows a perfect balance of flows through the pipe network consisting of 106 pipes and 15 loops in its calculation. The system has loops within the loop, four in all. The FHC software easily produced the hydraulic calculations for this system, showing its versatility.

Fire sprinkler systems often use a tree pipework configuration in their design. Although this configuration is not as hydraulically efficient as a loop or grid system, it still has its uses.

For complex buildings such as schools, residential care homes and systems that require a dry fire sprinkler installation, a tree system can be the way to go. The pipework in tree-work configurations can be sized conventionally using pre-sized pipe tables for the number of sprinkler heads, or by fully calculating the hydraulics by hand, though even for small systems, this is still very time-consuming and prone to human error.

By using FHC, you gain all the advantages of full hydraulic calculations to help you reduce your pipe sizes and/or water demand. Furthermore, the calculations will not include human error and will take only a fraction of a second to complete, allowing you, the designer, more time to optimise the system and reduce costs.

Deluge installation of any type can be modelled with the FHC program. In this example, medium-velocity sprayers protect a vertical cylinder. Within the FHC hydraulic model, we specified an area for each nozzle and a minimum design density of 10 mm/min.

A calculation for a high-pressure water mist fire protection system designed to NFPA 750. For high-pressure systems, you should use the Darcy-Weisbach pressure loss equation, which accounts for both the fluid's absolute viscosity (centipoises) and its density.

The water supply can be from a pressurised cylinder, a constant pressure pump, or any other type of water supply. Custom nozzle and pipe data files can be used for the hydraulic modelling of water mist systems.  Canute can provide customised pipe data files and nozzle data files based on any water mist manufacturer's data.

This hydraulic model represents a large storage tank with a fixed cone roof and is protected by three foam chambers. The foam chambers are located above the tank's liquid level, and the deflector is inside the tank to distribute the foam solution across the surface.
The number of foam chambers is determined by the tank diameter for a fixed cone or open top tank, and the flow rate can be calculated by multiplying the area by the required density.

The tank in this example has a diameter of 30m and therefore a surface area of 707m2. If we base the design density on 4.1 mm/min, this will give us a minimum flow rate of 2899 L/min and require a minimum of two foam chambers. However, to achieve faster foam distribution, we have used three. Also, the volume of foam from each pourer is reduced, which will allow for a smaller riser pipe for each foam chamber. For this design, we have used 80mm Viking Model FC foam chambers, with each chamber protecting a 236m2 area and requiring a minimum discharge of 699 L/min. Using the manufacturer's design table, we determine that we require a minimum pressure of 4.14 Bar at the foam chamber inlet.

With the above information, we can now proceed to start the hydraulic calculation for the systems. Still, instead of using a sprinkler or head as the output device, we can specify in FHC the required flow rate and pressure for each foam chamber on our system in the optional items section of the Project Data. When we calculate the hydraulic model in FHC, we find that we will require a source duty of 2122 L/min @ 5.525 Bar.

You can find out more information about the protection of storage tanks in NFPA 11: Standard for low, medium, and high-expansion foam