Deluge/Sprinkler System

medium 64 models total

A deluge or sprinkler system floods a protected space with water through open or heat-activated nozzles, deluge systems dousing an entire area at once on manual or automatic release, sprinklers responding zone by zone as individual heads activate.

Read more — Deluge/Sprinkler System explained ▾

What Sets Deluge and Sprinkler Apart

Both systems distribute water through overhead piping and nozzles, but they release differently. A sprinkler system uses heat-sensitive heads that open individually as the temperature around them rises, so only the heads actually over the fire discharge, limiting water damage to the affected zone. A deluge system uses open nozzles on every branch of the protected section, held dry until a detection system or manual pull station opens a common deluge valve, flooding the whole section at once. Sprinklers suit accommodation and machinery spaces where a slow-developing fire is expected; deluge suits fast-flashover risks such as a paint locker or a helicopter deck fuel spill, where waiting for individual heads to react would be too slow.

Deluge / sprinkler system schematic — Flow schematic from the fire main through the deluge valve to open nozzles flooding a protected area, with the heat detection line and manual release station shown.

Main Components

Detection and Release

Automatic sprinkler heads detect and release themselves; deluge systems instead rely on a separate fire detection loop or manual pull stations to open the deluge valve for the whole section.

Deluge/Alarm Valve

The key control element on a deluge system, normally held shut against system pressure until a detection signal or manual release opens it, admitting water to all open nozzles downstream simultaneously.

Pressure Tank and Pump

Sprinkler systems keep the piping pressurized from a dedicated tank for instant discharge on the first head opening, backed by an automatic pump that starts on falling pressure to sustain flow.

Section Isolation Valves

Divide the ship into zones so one section can be tested, drained or isolated for maintenance without disabling protection elsewhere.

Selection and Sizing

Water density (litres per minute per square metre) required for the specific space, set by the applicable fire safety rules
Pump capacity sized for the largest single section likely to discharge at once, not the whole system total
Head or nozzle spacing matched to ceiling height and obstruction layout
Response time requirement, faster for deluge-protected high-risk spaces than for general sprinkler zones

Regulations and Class

SOLAS Ch. II-2 and the FSS Code set water application rates, coverage and pump capacity requirements for both sprinkler systems in accommodation spaces and deluge systems in high-risk areas. Passenger ships and many cargo ship types must fit an automatic sprinkler system in accommodation under SOLAS regulation II-2/10, and helicopter decks commonly require deluge protection as a specific carriage requirement.

Typical Faults

Fault	Consequence
Deluge valve diaphragm perished or stuck	Valve fails to open on release signal, or opens without command, causing a false flood
Sprinkler pressure tank low on air charge	Delayed or reduced initial discharge before the pump takes over
Section isolation valve left shut after maintenance	An entire zone silently loses protection with no visible alarm indication
Sprinkler heads painted over during accommodation refurbishment	Heads fail to activate at the design temperature

What to Look for in a Supplier

Application rate and pump duty calculations matched to the specific protected spaces, backed by class-approved drawings
Valve and head components compatible with existing zone wiring and detection loop, if retrofitting
Clear zone isolation labelling and testing procedures supplied with the system, not left to the yard

After any accommodation repaint, check every sprinkler head by hand for overspray - a painted-over head looks fine on inspection but will not activate at the fire's design temperature.

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6 manufacturers · 64 models

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Application

Deluge and Preaction Fire Protection Systems

Common Failures & Inspection Points

Area: Diaphragm Integrity and Leakage
Check: Inspect for water or air leakage from bonnet cover and outlet drain; verify no external moisture on diaphragm chamber; perform annual full trip test to verify diaphragm response and proper valve opening
Area: Strainer and Filter Blockage
Check: Clean strainer in diaphragm chamber supply control valve; inspect for sediment, corrosion debris, or mineral deposits; perform internal inspection of strainers every 5 years per NFPA 25; replace if significant blockage detected
Area: Pilot Line Pressure and Air Supply
Check: Verify dry pilot line air pressure maintained at design pressure (typically 40-50 psi); check for air leaks at connections; ensure air drier functioning and dew point below lowest ambient temperature; test pressure gauge reading weekly
Area: Nozzle and Sprinkler Condition
Check: Inspect all deluge nozzles/sprinklers for corrosion, mechanical damage, or buildup; verify proper orientation and alignment; check for blockage or paint over orifices; ensure DN-5 duct nozzles maintain HALAR coating integrity
Area: Control Valve Assembly Condition
Check: Check for external corrosion on valve body, actuators, and piping; verify bonnet bolts are tight; inspect manual reset actuator (MRA-1) for damage; ensure dry pilot actuators (DP-1/DP-2) have no water/air leakage at drain outlet

Typ-universelle Inspektionspunkte fuer Fixed Fire Suppression (verifiziert, 2026-06).