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BS EN 14972-1:2020+A1:2025 Fixed firefighting systems. Water mist systems - Design, installation, inspection and maintenance, 2025
- undefined
- European foreword
- Introduction [Go to Page]
- Water mist systems
- 1 Scope
- 2 Normative references
- 3 Terms, definitions and abbreviations [Go to Page]
- 3.1 Terms and definitions
- 3.2 Abbreviations
- 4 Design [Go to Page]
- 4.1 Design principal [Go to Page]
- 4.1.1 General
- 4.1.2 General requirement
- 4.1.3 Full scale fire testing procedures [Go to Page]
- 4.1.3.1 General
- 4.1.3.2 Test protocols
- 4.2 Design, installation, operation and maintenance manual [Go to Page]
- 4.2.1 General
- 4.2.2 Content of the DIOM manual
- 4.3 Water mist systems using gas for their operation
- 4.4 Use of additives
- 4.5 Design parameters
- 4.6 Water and gas supply [Go to Page]
- 4.6.1 Pumped systems requirements
- 4.6.2 Self-contained systems requirements
- 4.7 Compartment protection [Go to Page]
- 4.7.1 General
- 4.7.2 Compartment
- 4.7.3 Fire hazard
- 4.7.4 Design requirements
- 4.8 Requirements for different types of water mist deluge systems [Go to Page]
- 4.8.1 Local application systems
- 4.8.2 Local application systems with multiple hazards
- 4.8.3 Volume protection water mist systems
- 4.8.4 Zoned protection systems
- 4.8.5 Activation and control [Go to Page]
- 4.8.5.1 Activation
- 4.8.5.2 Fire detection and fire alarm system and activation system
- 4.8.5.3 Intermittent systems
- 4.9 Design of water mist automatic nozzle systems [Go to Page]
- 4.9.1 Extent of protection
- 4.9.2 Permitted exceptions within a building
- 4.9.3 Material reaction
- 4.9.4 System design [Go to Page]
- 4.9.4.1 General
- 4.9.4.2 Hydraulic calculations
- 4.9.4.3 Area of operation
- Table 1 — Design criteria [Go to Page]
- 4.9.4.4 Requirements for different types of automatic nozzle water mist systems [Go to Page]
- 4.9.4.4.1 Wet pipe water mist systems
- 4.9.4.4.2 Dry pipe systems
- 4.9.4.4.3 Pre-action water mist systems
- 4.9.4.4.4 Area limitation
- 4.9.4.4.5 Determination of material factor
- Figure 1 — Material factor [Go to Page]
- 4.9.4.4.6 Effect of storage configuration
- Table 2 — Categories as a function of storage configuration [Go to Page]
- 4.9.5 Nozzle selection and positioning [Go to Page]
- 4.9.5.1 Nominal operating temperature for automatic nozzles
- 4.9.5.2 Nozzle selection
- 4.9.5.3 Nozzle positioning
- 4.9.6 Alarm device
- 4.9.7 Test connection
- 4.9.8 Air velocity and openings
- 4.10 Design of water mist deluge system [Go to Page]
- 4.10.1 Nozzle selection and positioning [Go to Page]
- 4.10.1.1 Nozzle selection
- 4.10.1.2 Nozzle positioning
- 4.10.2 Air velocity and openings
- 4.10.3 Automatic shut-down [Go to Page]
- 4.10.3.1 Ventilation in the protected area
- 4.10.3.2 Fuel and other combustibles used in the protected area
- 4.10.3.3 Power supply to equipment in the protected area
- 4.11 Fire detection and fire alarm systems activating the water mist system [Go to Page]
- 4.11.1 General requirements
- 4.11.2 Fire detection and fire alarm systems continuity
- 4.11.3 Avoiding false alarms by water mist discharge
- 4.11.4 Manual activation
- 4.11.5 Electrical detection and activation [Go to Page]
- 4.11.5.1 General
- 4.11.5.2 Electrical equipment
- 4.11.5.3 Fire detection and fire alarm systems control panel
- 4.11.5.4 Fire detection and fire alarm systems power supply [Go to Page]
- 4.11.5.4.1 Electric power supply
- 4.11.5.4.2 Electrical power supply dimensioning
- 4.11.5.5 Fire detection and fire alarm system power supply isolating switch
- 4.11.5.6 Alarm and fault indications [Go to Page]
- 4.11.5.6.1 General
- 4.11.5.6.2 Alarm and fault signals
- 4.11.6 Non-electrical detection [Go to Page]
- 4.11.6.1 General
- 4.11.6.2 Pneumatic fire detection and fire alarm systems
- 4.11.6.3 Pneumatic or hydraulic system supervision
- 4.12 Hydraulic and pneumatic calculations
- 4.13 Water, propellant and atomizing gas supply design [Go to Page]
- 4.13.1 General
- 4.13.2 Connection to public or town mains
- 4.13.3 Flow requirement [Go to Page]
- 4.13.3.1 Flow requirement for water mist automatic nozzle systems
- 4.13.3.2 Flow requirement for deluge water mist systems
- 4.13.4 Maximum and minimum water pressure
- 4.13.5 Discharge operating time
- Table 3 — Minimum discharge operating time
- Table 4 — Minimum time of operation [Go to Page]
- 4.13.6 Type of water supply [Go to Page]
- 4.13.6.1 Acceptable sources of water supply
- 4.13.6.2 Acceptable propellant/atomizing gas supply systems
- 4.13.7 Availability [Go to Page]
- 4.13.7.1 General
- 4.13.7.2 Reduced capacity water reservoir
- Key
- Figure 2 — Effective capacity of tank with a vortex inhibitor (example)
- Key
- Figure 3 — Effective capacity of tank without a vortex inhibitor (example) [Go to Page]
- 4.13.7.3 Frost protection
- 4.13.8 Housing of equipment for water supplies [Go to Page]
- 4.13.8.1 Equipment housing
- 4.13.8.2 Fire protection
- 4.13.8.3 Temperature
- 4.13.8.4 Ventilation
- 5 Installation [Go to Page]
- 5.1 General [Go to Page]
- 5.1.1 DIOM manual
- 5.1.2 Electrical safety
- 5.1.3 High Voltage live electrical equipment
- 5.1.4 Electrical clearances
- Table 5 — Clearance from water mist systems to live uninsulated electrical components [Go to Page]
- 5.2 Nozzle [Go to Page]
- 5.2.1 General [Go to Page]
- 5.2.1.1 Nozzle installation
- 5.2.1.2 Installation height of nozzles
- 5.2.1.3 Nozzle spacing
- 5.2.1.4 Nozzle protection
- 5.2.1.5 Nozzle Escutcheons and cover plates
- 5.2.2 Automatic nozzle [Go to Page]
- 5.2.2.1 Distance of nozzle from the ceiling
- 5.2.2.2 Distance of nozzles from walls
- 5.2.2.3 Ceiling slope
- 5.2.2.4 Obstruction
- 5.2.3 Open nozzle [Go to Page]
- 5.2.3.1 Distance from the hazard
- 5.2.3.2 Obstruction
- 5.3 Pipe [Go to Page]
- 5.3.1 General
- 5.3.2 Protection against mechanical damages
- 5.3.3 Protection against corrosion
- 5.3.4 Protection in seismic areas
- 5.3.5 Protection against freezing for wet pipes
- 5.3.6 Accessibility of the pipe work
- 5.3.7 Pipe bending [Go to Page]
- 5.3.7.1 General
- 5.3.7.2 Pipe bending tools
- 5.3.8 Water supply pipes
- 5.3.9 Pipe support [Go to Page]
- 5.3.9.1 General
- 5.3.9.2 Pipe support spacing
- Table 6 — Maximum spacing of pipe supports for pipes with less than 2,6 mm wall thickness
- Table 7 — Maximum spacing of pipe supports for pipes with minimum 2,6 mm wall thickness [Go to Page]
- 5.3.9.3 Pipe support positioning
- 5.3.10 Drainage
- 5.4 Gas and water containers (where provided) [Go to Page]
- 5.4.1 General
- 5.4.2 Location
- 5.4.3 Accessibility
- 5.4.4 Fixing
- 5.4.5 Manifolds
- 5.4.6 Temperature
- 5.5 Strainers and filters [Go to Page]
- 5.5.1 Strainers
- 5.5.2 Nozzle filter
- 5.5.3 System filters
- 5.6 Valves [Go to Page]
- 5.6.1 General
- 5.6.2 Identifications
- 5.6.3 Accessibility
- 5.6.4 Securing and monitoring valves
- 5.6.5 Shut-off valves
- 5.6.6 Control valves
- 5.6.7 Check and non-return valves
- 5.7 Pressure gauges
- 5.8 Test connection [Go to Page]
- 5.8.1 Test connection for automatic water mist systems
- 5.8.2 Test connection for water mist deluge system
- 5.9 Electrical installation [Go to Page]
- 5.9.1 Electrical power supply
- 5.9.2 Fire detection and fire alarm system
- 5.10 System monitoring and alarms [Go to Page]
- 5.10.1 General
- 5.10.2 Alarms [Go to Page]
- 5.10.2.1 System activation
- 5.10.2.2 Other alarms
- 5.10.2.3 System failure
- 5.10.3 Remote signalling
- 5.11 Water mist system supply, including additives [Go to Page]
- 5.11.1 General
- 5.11.2 Water quality [Go to Page]
- 5.11.2.1 Water source
- 5.11.2.2 Maximum temperature of water
- 5.11.3 Additives [Go to Page]
- 5.11.3.1 General
- 5.11.3.2 Identification
- 5.11.3.3 Adversely effects of additives
- 5.11.4 Water supply [Go to Page]
- 5.11.4.1 Self-contained system
- 5.11.4.2 Pump system requirements [Go to Page]
- 5.11.4.2.1 General
- 5.11.4.2.2 Tanks [Go to Page]
- 5.11.4.2.2.1 General
- 5.11.4.2.2.2 Filtering device
- 5.11.4.2.2.3 Tank accessories
- 5.11.4.2.2.4 Identification
- 5.11.4.2.2.5 Monitoring
- 5.11.4.2.3 Connections to water networks [Go to Page]
- 5.11.4.2.3.1 General
- 5.11.4.2.3.2 Connections to water networks as system supply
- 5.11.4.2.3.3 Connections to water networks for tank filling
- 5.11.4.2.3.4 Connections for fire brigade
- 5.11.4.2.4 Jockey pumps [Go to Page]
- 5.11.4.2.4.1 Capacity
- 5.11.4.2.4.2 Operation
- 5.11.4.2.4.3 Test connection
- 5.11.4.2.4.4 Overpressure protection
- 5.11.4.2.5 Atomizing gas compressor
- 5.11.5 Test devices [Go to Page]
- 5.11.5.1 Self-contained systems
- 5.11.5.2 Town main supplied systems
- 6 Water mist system components [Go to Page]
- 6.1 General [Go to Page]
- 6.1.1 Requirements for components
- 6.1.2 Pressure rating
- 6.2 Nozzle
- 6.3 Piping and fittings [Go to Page]
- 6.3.1 Pipework [Go to Page]
- 6.3.1.1 Pressure rating
- 6.3.1.2 Pipe identification
- 6.3.1.3 Pipe bending
- 6.3.1.4 Welded joints
- 6.3.1.5 Threaded joints
- 6.3.1.6 Mechanical joints
- 6.3.2 Fittings [Go to Page]
- 6.3.2.1 General
- 6.3.2.2 Threaded fittings
- 6.3.2.3 Mechanical joints
- 6.3.2.4 Distribution blocks
- 6.4 Flexible hoses [Go to Page]
- 6.4.1 Hose length
- 6.4.2 Hoses to be used in areas exposed to fire class B fires
- 6.4.3 Hose rating
- 6.5 Pipe supports
- 6.6 Valves [Go to Page]
- 6.6.1 Shut-off valves
- 6.6.2 Pressure regulating valves
- 6.6.3 Check and non-return valves
- 6.6.4 Drain/fill valves
- 6.6.5 Safety valves
- 6.7 Control valves [Go to Page]
- 6.7.1 General
- 6.7.2 Strainers and filters
- 6.8 Flow switches and flow transmitters
- 6.9 Pressure switches and pressure transmitters
- 6.10 Supply components for self-contained systems [Go to Page]
- 6.10.1 General
- 6.10.2 Excess pressure
- 6.10.3 Pressure container marking
- 6.10.4 Design temperature
- 6.10.5 Gas cylinders and actuation valve
- 6.10.6 Cylinders and storage containers for water
- 7 Main pumps for water mist systems [Go to Page]
- 7.1 General
- 7.2 Pump set [Go to Page]
- 7.2.1 Operation
- 7.2.2 Overpressure
- 7.2.3 Centrifugal pumps
- 7.2.4 Positive displacement pumps
- 7.2.5 Pump driver
- 7.2.6 Pump Cooling
- 7.2.7 Pump set anchoring
- 7.2.8 Positive displacement pump filters
- 7.2.9 Pump set coupling
- 7.2.10 Valves and accessories [Go to Page]
- 7.2.10.1 Shut off valve
- 7.2.10.2 Valve monitoring
- 7.2.11 Suction pipe [Go to Page]
- 7.2.11.1 Design for centrifugal pumps
- 7.2.11.2 Multiple units
- 7.2.12 Discharge pipe
- 7.2.13 Pump set rating [Go to Page]
- 7.2.13.1 Pump set capacity
- 7.2.13.2 Pump set redundancy
- 7.2.13.3 Pump set capacity calculation
- 7.2.13.4 Pressure and water capacity of town mains
- 7.2.14 Pump set operation [Go to Page]
- 7.2.14.1 Pressure devices [Go to Page]
- 7.2.14.1.1 Pressure sensing devices
- 7.2.14.1.2 Testing the pressure sensing devices
- 7.2.14.2 Pump set start
- 7.2.14.3 Pump set stop
- 7.2.15 Electrically driven pump sets [Go to Page]
- 7.2.15.1 General
- 7.2.15.2 Power supply documentation
- 7.2.15.3 Electricity supply [Go to Page]
- 7.2.15.3.1 General
- 7.2.15.3.2 Supply cables
- 7.2.15.3.3 Supply cables lengths
- 7.2.15.3.4 Premises switchboard [Go to Page]
- 7.2.15.3.4.1 Premises switchboard location
- 7.2.15.3.4.2 Premises switchboard independency
- 7.2.15.3.4.3 Premises switchboard identification
- 7.2.15.3.4.4 Installation between the main switchboard and the pump unit controller
- 7.2.15.4 Electric pump set controller [Go to Page]
- 7.2.15.4.1 General
- 7.2.15.4.2 Pump set controller functions
- 7.2.15.4.3 Pump set controller instrumentation
- 7.2.15.4.4 Pump set controller location
- 7.2.15.4.5 Pump set controller construction
- 7.2.15.4.6 Monitoring of pump operation
- 7.2.16 Diesel engine driven pump sets [Go to Page]
- 7.2.16.1 General
- 7.2.16.2 Engines
- 7.2.16.3 Engine cooling system
- 7.2.16.4 Ventilation [Go to Page]
- 7.2.16.4.1 Air intake for engine operation
- 7.2.16.4.2 Exhaust system
- 7.2.16.4.3 Fuel, fuel tank and fuel feed pipes
- 7.2.16.4.4 Starting mechanism [Go to Page]
- 7.2.16.4.4.1 General
- 7.2.16.4.4.2 Automatic starting system
- 7.2.16.4.4.3 Emergency manual starting system
- 7.2.16.4.4.4 Test facility for manual starting system
- 7.2.16.4.4.5 Starter motor
- 7.2.16.4.4.6 Electric starter motor batteries
- 7.2.16.4.4.7 Battery chargers
- 7.2.16.4.4.8 Positioning of batteries and chargers
- 7.2.16.4.4.9 Starter indication
- 7.2.16.4.4.10 Tools and spare parts
- 7.2.16.4.5 Engine test before installation
- 8 Testing, acceptance and commissioning [Go to Page]
- 8.1 Acceptance test for water mist systems
- 8.2 Test criteria
- 8.3 Site commissioning test
- 8.4 Completion certificate and documents
- 9 Inspection and maintenance [Go to Page]
- 9.1 Inspection [Go to Page]
- 9.1.1 Inspection schedule
- 9.1.2 User's program of inspection
- 9.2 Inspection and maintenance routines [Go to Page]
- 9.2.1 Weekly routine [Go to Page]
- 9.2.1.1 General
- 9.2.1.2 Checks
- 9.2.1.3 Pump starting test
- 9.2.1.4 Diesel engine restarting test
- 9.2.2 Monthly routine [Go to Page]
- 9.2.2.1 Trace heating and localized heating systems
- 9.2.3 Quarterly routine [Go to Page]
- 9.2.3.1 General
- 9.2.3.2 Water supplies
- 9.2.3.3 Electrical supplies
- 9.2.3.4 Shut-off valves
- 9.2.3.5 Fire alarm flow and/or pressure switches
- 9.2.3.6 Replacement
- 9.2.4 Half-yearly routine [Go to Page]
- 9.2.4.1 General
- 9.2.4.2 Dry and deluge valves
- 9.2.4.3 Test of fire detection and alarm system
- 9.2.5 Annual inspection [Go to Page]
- 9.2.5.1 General
- 9.2.5.2 Review of hazard
- 9.2.5.3 Water mist nozzles
- 9.2.5.4 Automatic pump set flow test
- 9.2.5.5 Diesel engine failed-to-start test
- 9.2.5.6 Infill valves on water storage tanks
- 9.2.5.7 Pump and system strainers
- 9.2.5.8 Pipework and pipe supports
- 9.2.5.9 Examination of cylinders and tanks
- 9.2.5.10 Remote alarm transmission
- 9.2.5.11 System integrity
- 9.2.6 Three-yearly routine [Go to Page]
- 9.2.6.1 General
- 9.2.6.2 Storage tanks
- 9.2.6.3 Water supply shut-off valves, control and check valves
- 9.2.7 Five-yearly routine [Go to Page]
- 9.2.7.1 General
- 9.2.7.2 Testing of nozzles
- 9.2.8 Ten-yearly routine [Go to Page]
- 9.2.8.1 General
- 9.2.8.2 Pipework
- 9.2.9 Maintenance schedule
- 9.2.10 User's program of monitoring
- 9.2.11 Training
- 10 Documentation [Go to Page]
- 10.1 Installation documentation
- 10.2 Documentation for acceptance of design, installation and commissioning
- Annex A (informative) Guideline for developing representative fire test protocols for water mist systems
- A.1 General
- A.2 Evaluation of the fire hazard
- Figure A.1 — Process of developing a fire test procedure
- A.3 Evaluation of the compartment conditions
- A.4 Determining the performance objective
- A.5 Setting up the fire test procedure
- A.6 Carrying out the test
- A.7 Documentation and interpretation of test results
- A.8 Example for fire test report
- Annex B (informative) Area of operation for typical automatic nozzle water mist systems
- B.1 General
- B.2 Typical system component layouts
- B.2.1 System components gridded layout
- Figure B.1 — System components gridded layout
- B.2.2 System components terminal layout
- Figure B.2 — System components terminal layout
- B.2.3 System components looped layout
- Figure B.3 — System components looped layout
- B.3 AOs to be determined by full hydraulic calculation
- Figure B.4 — Selection of hydraulically most remote operating area
- Figure B.5 — Selection of hydraulically most favourable operating area
- B.4 Most unfavourable and most favourable AO demands and the pump supply curve
- Figure B.6 — Most unfavourable and most favourable AO demands and the pump supply curve
- B.5 Calculating the number of nozzles and actual area of AO
- Figure B.7 — Calculating the number of nozzles
- B.6 Method of calculating the area per nozzle
- B.6.1 Regular spacing
- Figure B.8 — How to calculate the area per nozzle (regular spacing)
- B.6.2 Irregular spacing
- Figure B.9 — How to calculate the area per nozzle (irregular spacing)
- Figure B.10 — Actual area per nozzle
- Figure B.11 — Area per nozzle – irregular nozzle spacing – further examples
- B.7 Shape of the AO
- B.7.1 General
- B.7.2 Shape of the hydraulically most unfavourable location
- Figure B.12 — Hydraulically most unfavourable area terminal layout
- Figure B.13 — Hydraulically most unfavourable area looped layout
- Figure B.14 — Hydraulically most unfavourable area in a normal gridded layout
- Figure B.15 — Hydraulically most unfavourable area, gridded layout ranges parallel to roof
- B.7.3 Shape of the hydraulically most favourable location
- Figure B.16 — Hydraulically most favourable area terminal layout
- Figure B.17 — Hydraulically most favourable area looped layout
- Figure B.18 — Hydraulically most favourable area in a gridded layout
- B.8 Length of the AO
- Figure B.19 — Guidance where the length of the AO starts and finishes
- B.9 Relocation of section valves
- Figure B.20 — Relocation of section valves
- B.10 Calculating the nozzles operating in the most unfavourable AO
- Figure B.21 — Calculating the nozzles operating in a hydraulically most unfavourable AO of 72 m2
- Annex C (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-2
- C.1 General
- C.2 Regarding the scope of the water mist system
- C.2.1 General
- C.2.2 Storage areas
- Figure C.1 — Storage types
- Table C.1 — Limitations and additional requirements for different storage types
- C.3 Storage requirements
- Table C.2 — Maximum storage height for stored goods
- Annex D (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-3
- D.1 General
- D.2 Regarding the scope of the water mist system
- Table D.1 — Examples for applicability
- D.3 Additional design and installation parameters
- Annex E (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-4
- E.1 General
- E.2 Regarding the scope of the water mist system
- E.3 Additional information on testing methodology
- Annex F (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-5
- F.1 General
- F.2 Regarding the scope of the water mist system
- Annex G (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-6
- G.1 General
- G.2 Regarding the scope of the water mist system
- Annex H (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-7
- H.1 General
- H.2 Regarding the scope of the water mist system
- Table H.1 — Hazard category restrictions
- Annex I (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-8
- I.1 General
- I.2 Regarding the scope of the water mist system
- Table I.1 — Examples for applicability
- Annex J (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-9
- J.1 General
- J.2 Regarding the scope of the water mist system
- Table J.1 — Examples of applicability
- J.3 Additional design and installation parameters
- Annex K (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-10
- K.1 General
- K.2 Regarding the scope of the water mist system
- K.3 Additional design and installation parameters
- Annex L (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-11
- L.1 General
- L.2 Regarding the scope of the water mist system
- L.3 Additional design and installation parameters
- Annex M (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-12
- M.1 Regarding the scope of the water mist system
- M.2 Additional design and installation parameters
- Annex N (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-13
- N.1 Additional design and installation parameters
- Annex O (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-14
- O.1 General
- O.2 Regarding the scope of the water mist system
- O.3 Additional design and installation parameters
- Annex P (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-15
- P.1 General
- P.2 Regarding the scope of the water mist system
- P.3 Additional design and installation parameters
- Annex Q (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-16
- Q.1 Regarding the scope of the water mist system
- Q.2 Additional design and installation parameters
- Annex R (normative) Limits of applicability for water mist systems tested in accordance with EN 14972-17
- R.1 General
- R.2 Regarding the scope of the water mist system
- R.3 Additional design and installation parameters
- R.3.1 Consultation
- R.3.2 System Enhancements
- Annex S (normative) Measurement tolerances
- Table S.1 — Measurement tolerances
- Bibliography
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