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Fire Protection Design

Digital Design and Consultancy provide fire sprinkler design in accordance with industry standards including Loss Prevention Council Rules, FM Global Data Sheets, NFPA Standard and BS 9251 Residential Standards.


All designs are carried out by certified Sprinkler and Mechanical Engineers using the latest innovations in 3D design software packages. Our expertise in design allows us to produce intelligent models for the operation and maintenance of the clients-built asset. All 2D output produced is extracted directly from the 3D model ensuring information provided is accurate and up to date.


Our expertise in Fire Protection Design using the following design codes:

  • LPC /BSEN 12845 Sprinkler Design Code

  • FM Global Design Codes

  • NFPA Sprinkler Design Codes

  • BS 9251: 2020 Residential and Domestic Sprinkler Systems


We offer the complete design of fire sprinkler systems, including Wet, Dry, Pre-action and Deluge systems.

Types of Fire Protection System

Wet systems

The wet alarm valve is the most common arrangement of alarm valve. The pipes are filled with water under pressure and are only installed in frost resistant building areas. 

When an automatic sprinkler is exposed for a sufficient time to a temperature at or above the temperature rating, the heat-sensitive element breaks, allowing water to flow from the sprinkler.


Wet Pipe Systems have two principal functions.

  1. Acts as a non-return or check valve

  2. Sounds an alarm when water flows

Dry Systems

Dry alarm valves are most used in installations subject to freezing or hot process risks where range temperatures exceed 70°C. Dry pipe systems are typically used in refrigerated coolers, car parking area and in unheated buildings or water sensitive areas, since dry pipe systems do not leak water.

The sprinkler piping is filled with pressurised air. A special alarm valve is used to separate the sprinkler pipe and the water supply pipe. When one or more of the automatic sprinklers is exposed to a temperature at or above the temperature rating, it opens, allowing the air in the piping to vent from that sprinkler. When the air pressure in the piping drops, the pressure difference across the alarm valve changes. This will force the alarm valve to open, allowing water to enter the piping system. The water flow from the sprinklers is delayed until the air is vented from the sprinklers.


Dry pipe systems are therefore not as fast acting in the initial phase of a fire. But the only delay before water is distributed via the sprinklers is from the time to vent the air from the pipe. This means that the potential for severe water damage exists. Dry pipe alarm valves should only be used where it is impractical to employ a wet pipe alarm valve and should be avoided in high hazard applications.

Pre-action systems

Pre-action alarm valves are variations on the dry pipe alarm valve. They are commonly used in sensitive areas i.e. Data Centres, computer rooms etc. where accidental activation is undesired. They additionally employ an independent fire detection system and control panel. The fire detection system is either used to accelerate operation of the pre-action valve by opening it in advance of a sprinkler head operation or to prevent unintentional water discharge from a damaged sprinkler head.

Deluge Valves

The Deluge pipe alarm valve is designed to operate as a wet pipe when there is no risk of freezing and a dry valve in the winter months when there is the possibility of freezing. This is a system where all connected sprinklers are open. These sprinklers have no sensing element. This is usually in areas where rapid fire spread is expected and often where cooling storage tanks or plant may be necessary. The open sprinklers will distribute water over the entire area. The piping is filled with atmospheric pressure, and a mechanically activated deluge valve will open in case of fire, enabling the water to fill the sprinkler pipe. The deluge valve is activated by a signal from a fire alarm system and remains open once it has been activated. The fire alarm system consists of smoke or heat detectors activating the alarm system, which opens the deluge valve.

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