Pre-Action and Deluge Sprinkler Systems
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 6
to Rev 7
in Pre-Action and Deluge Sprinkler Systems.
---
title: Pre-Action and Deluge Sprinkler Systems
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### The Contractor shall confirm designer qualification requirements for both the water-side and detection-side disciplines before assigning the design work.
−### The water-side layout shall be prepared by a licensed fire protection engineer or a NICET-certified sprinkler designer, and the detection and releasing design by a person holding NICET certification in fire alarm systems or a licensed engineer, as required by the jurisdiction. {note}
+### The water-side layout shall be prepared by a licensed fire protection engineer or a NICET-certified sprinkler designer, and the detection and releasing design by a person holding NICET certification in fire alarm systems or a licensed engineer, as required by the jurisdiction.
## Closeout Submittals {toc}
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```
−### Where the building's property insurance carrier or the Owner requires FM Global compliance, all components shall be FM-approved in addition to UL-listed.
−
### FM and UL listings are not identical, and cross-zoned detection arrangements accepted under one listing or jurisdiction may not be accepted under another. {note}
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### Internal corrosion is an aggressive problem in pre-action and deluge systems: residual water trapped at low points after testing or a release, combined with the oxygen in the supervisory air (pre-action) or the open atmosphere (deluge), drives microbiologically influenced corrosion (MIC) and oxygen pitting that can perforate the pipe wall over the service life. {note}
+### For pre-action systems the Contractor shall provide one of three corrosion-mitigation approaches: galvanized steel pipe throughout; nitrogen inerting using a listed nitrogen generator that displaces oxygen; or both, where the Owner's risk profile or insurance requirements warrant enhanced protection.
+
```datasheet
label: Corrosion Mitigation Approach
…7 unchanged lines
```
−### For pre-action systems the Contractor shall provide one of three corrosion-mitigation approaches: galvanized steel pipe throughout; nitrogen inerting using a listed nitrogen generator that displaces oxygen; or both, where the Owner's risk profile or insurance requirements warrant enhanced protection.
−
### NFPA 13 recognizes nitrogen inerting as an alternative to galvanized pipe for corrosion control on supervised dry systems, and nitrogen is the default for long-life critical assets such as data centers and freezer warehouses. {note}
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min: 40
max: 250
− setpoints: [100, 125, 150, 175, 200, 250]
+ setpoints: [40, 100, 125, 150, 175, 200, 250]
default: 150
```
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### Hazard classification determines the design density, the design area, and therefore the flow and pressure demand on the water supply. {note}
+### The hazard classification shall be assigned by the designer based on the occupancy descriptions in NFPA 13 Chapter 5 and confirmed with the Owner and the AHJ before the hydraulic design is finalized.
+
```datasheet
label: Predominant Occupancy Hazard Classification
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```
−### The hazard classification shall be assigned by the designer based on the occupancy descriptions in NFPA 13 Chapter 5 and confirmed with the Owner and the AHJ before the hydraulic design is finalized.
−
### Pre-action systems most commonly protect Light Hazard and Ordinary Hazard occupancies, while archives and records storage may be Light Hazard or may invoke the storage rules. {note}
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### The hose stream allowance is the same as for a wet-pipe system at the same hazard classification: 100 gpm for light hazard, 250 gpm for ordinary hazard, and 500 gpm for extra hazard. {note}
+### The hose stream allowance shall be specified to match the hazard classification of the sprinkler or deluge design.
+
```datasheet
label: Hose Stream Allowance
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### Because deluge demand is large with all heads flowing, deluge systems frequently require a fire pump. {note}
+### Water supply data shall be obtained by a hydrant flow test conducted at or near the project site in accordance with NFPA 291, no more than 12 months prior to the date of submittal.
+
```datasheet
label: Water Supply Source
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```
+### Static pressure, residual pressure, and pitot flow shall be recorded.
+
```datasheet
label: Static Pressure at Flow Test
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min: 20
max: 150
− setpoints: [40, 50, 60, 70, 80, 90, 100, 120, 150]
+ setpoints: [20, 40, 50, 60, 70, 80, 90, 100, 120, 150]
default: 70
```
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min: 10
max: 130
− setpoints: [20, 30, 40, 50, 60, 70, 80, 100, 130]
+ setpoints: [10, 20, 30, 40, 50, 60, 70, 80, 100, 130]
default: 50
```
−### Water supply data shall be obtained by a hydrant flow test conducted at or near the project site in accordance with NFPA 291, no more than 12 months prior to the date of submittal.
−
−### Static pressure, residual pressure, and pitot flow shall be recorded.
−
### The designer shall plot the supply curve and confirm that the system demand including hose stream falls below the supply curve with the safety margin required by NFPA 13.
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### When a detector operates, the releasing control unit energizes the release solenoid (or trips a pneumatic actuator), the pre-action valve opens, and water fills the piping up to the still-closed sprinklers; water then discharges only when a sprinkler subsequently opens from heat. {note}
+### The single interlock provides one layer of protection against accidental discharge: a physically broken sprinkler or fitting in a room with no fire releases supervisory air and signals a trouble condition, but it does not admit water, because no detector has operated.
+
+### Single-interlock systems are limited by NFPA 13 to no more than 1,000 automatic sprinklers controlled by any single pre-action valve.
+
```datasheet
label: Maximum Sprinklers per Pre-Action Valve
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min: 100
max: 1000
− setpoints: [250, 500, 750, 1000]
+ setpoints: [100, 250, 500, 750, 1000]
default: 1000
```
−### The single interlock provides one layer of protection against accidental discharge: a physically broken sprinkler or fitting in a room with no fire releases supervisory air and signals a trouble condition, but it does not admit water, because no detector has operated.
−
−### Single-interlock systems are limited by NFPA 13 to no more than 1,000 automatic sprinklers controlled by any single pre-action valve.
−
### Because water arrives on detection before the sprinklers open, the single-interlock system does not take the 30 percent design-area penalty.
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### The choice of detection device depends on the speed of detection required, the environment (temperature, dust, airflow, ceiling height), and the hazard. {note}
+### Detection devices shall be selected and spaced for the hazard and the protected environment in accordance with NFPA 72.
+
```datasheet
label: Releasing Detection Type
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```
−### Detection devices shall be selected and spaced for the hazard and the protected environment in accordance with NFPA 72.
−
### Detection devices shall be of a type listed for releasing service.
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### Cross-zoning guards against an accidental release from a single faulty or transient detector signal, which is exactly the failure mode that pre-action and deluge systems exist to prevent. {note}
+### For releasing service, where cross-zoned (coincidence) logic is used, two separate detection zones or two separate detectors shall operate before a release signal is issued.
+
```datasheet
label: Detection Releasing Logic
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```
−### For releasing service, where cross-zoned (coincidence) logic is used, two separate detection zones or two separate detectors shall operate before a release signal is issued.
−
### On a single-interlock pre-action system, cross-zoned detection alone releases the valve.
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### On electric release, the releasing control unit energizes or de-energizes the solenoid to vent the priming chamber and allow the valve to open. {note}
+### The valve type — single-interlock or double-interlock pre-action, or deluge — shall be specified for the system's hazard and release configuration.
+
```datasheet
label: Valve Type
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```
+### The valve release method — electric, pneumatic, or both — shall be specified and shall be compatible with the selected valve type.
+
```datasheet
label: Valve Release Method
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```
+### The pre-action or deluge valve size shall be specified to match the hydraulic design of the system.
+
```datasheet
label: Valve Size
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### Pre-action systems shall be maintained under supervisory air or nitrogen so that the loss of pressure from an opened sprinkler or damaged pipe is detected.
−### Deluge systems are open to atmosphere and are not air-supervised. {note}
```datasheet
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default: "Dedicated air compressor with listed air maintenance device"
```
+### Deluge systems are open to atmosphere and are not air-supervised. {note}
+### Where the supervisory gas is air, an air compressor with a listed air maintenance device shall be provided, and the air maintenance device shall limit the rate of air introduction so that a small leak is not masked by an oversized restoration capacity.
+
```datasheet
label: Air Compressor Restoration Time (pre-action)
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```
+### Where the supervisory gas is nitrogen, a listed nitrogen generator (membrane or pressure-swing adsorption) shall be provided, producing at least 98 percent nitrogen at the valve and purged to the listed purity at the most remote sprinkler.
+
```datasheet
label: Nitrogen Purity at Sprinkler (pre-action, where used)
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min: 90
max: 99
− setpoints: [95, 98, 99]
+ setpoints: [90, 95, 98, 99]
default: 98
```
−### Where the supervisory gas is air, an air compressor with a listed air maintenance device shall be provided, and the air maintenance device shall limit the rate of air introduction so that a small leak is not masked by an oversized restoration capacity.
−
−### Where the supervisory gas is nitrogen, a listed nitrogen generator (membrane or pressure-swing adsorption) shall be provided, producing at least 98 percent nitrogen at the valve and purged to the listed purity at the most remote sprinkler.
−
### Nitrogen is the preferred supervisory gas for data centers and freezer warehouses because it eliminates the oxygen that drives internal corrosion over the long service life of these critical assets. {note}
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### Pre-action systems use closed (automatic) sprinklers in which the thermal element holds the orifice closed until heat opens the individual sprinkler; deluge systems use open sprinklers or directional spray nozzles with no thermal element, every device permanently open and discharging the instant the valve trips. {note}
+### The discharge device type shall be specified as closed sprinklers for pre-action service or open sprinklers or nozzles for deluge service.
+
```datasheet
label: Discharge Device Type
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```
+### The sprinkler or nozzle K-factor shall be specified consistent with the hydraulic demand of the discharge device selected for the system.
+
```datasheet
label: Sprinkler / Nozzle K-Factor
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```
+### Where closed heads are used in pre-action service, the sprinkler thermal response shall be specified as standard or quick response.
+
```datasheet
label: Sprinkler Thermal Response (pre-action closed heads)
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```
+### Where closed heads are used in pre-action service, the sprinkler temperature rating shall be specified based on the anticipated ceiling temperature.
+
```datasheet
label: Sprinkler Temperature Rating (pre-action closed heads)
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### Steel pipe shall conform to ASTM A795 or ASTM A53; ASTM A795 is the purpose-written fire protection standard and is preferred.
−### The galvanized variant is strongly preferred over black for these normally dry systems unless a pre-action system is also nitrogen-inerted, because internal corrosion in cycled wet-dry environments is significantly more aggressive than in continuously wet systems. {note}
```datasheet
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default: "ASTM A795 (galvanized) — preferred"
```
+### The galvanized variant is strongly preferred over black for these normally dry systems unless a pre-action system is also nitrogen-inerted, because internal corrosion in cycled wet-dry environments is significantly more aggressive than in continuously wet systems. {note}
+### Steel pipe shall conform to ASTM A795 or ASTM A53, with ASTM A795 preferred.
+
+### Schedule 40 pipe shall be used for threaded joints in sizes 3 in. and smaller; Schedule 10 listed for dry-system service or Schedule 40 may be used for grooved or welded joints.
+
```datasheet
label: Primary Joining Method
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```
−### Steel pipe shall conform to ASTM A795 or ASTM A53, with ASTM A795 preferred.
−
−### Schedule 40 pipe shall be used for threaded joints in sizes 3 in. and smaller; Schedule 10 listed for dry-system service or Schedule 40 may be used for grooved or welded joints.
−
### Schedule 10 pipe shall not be threaded.
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### Inadequate pitch leaves trapped water that corrodes the pipe and, in cold applications, freezes and ruptures it. {note}
+### System piping shall be pitched to drain back to the valve or to auxiliary drains at low points.
+
+### NFPA 13 requires minimum pitch of 1/2 in. per 10 ft for branch lines and 1/4 in. per 10 ft for mains in steel-pipe systems.
+
```datasheet
label: Minimum Branch Line Pitch
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```
−### System piping shall be pitched to drain back to the valve or to auxiliary drains at low points.
−
−### NFPA 13 requires minimum pitch of 1/2 in. per 10 ft for branch lines and 1/4 in. per 10 ft for mains in steel-pipe systems.
−
### Deluge piping shall drain completely after every operation, because the open piping admits and retains test and discharge water at every low point.
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### Deluge systems, being open to atmosphere, are not air-tested. {note}
+### Pre-action systems shall be air-tested at 40 psi for 24 hours with a pressure loss not exceeding 1.5 psi, in accordance with NFPA 13, after the system is drained from the hydrostatic test and before it is placed in service.
+
```datasheet
label: Air Test (pre-action) Allowable Loss
…6 unchanged lines
```
−### Pre-action systems shall be air-tested at 40 psi for 24 hours with a pressure loss not exceeding 1.5 psi, in accordance with NFPA 13, after the system is drained from the hydrostatic test and before it is placed in service.
−
### Leaks shall be located by soap-bubble or ultrasonic testing and corrected before retest.
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### The trip test confirms the calculated trip-time and water-delivery values in practice. {note}
+### The pre-action or deluge valve shall be trip-tested by operating the detection system (and, for double-interlock systems, also venting the supervisory air) and confirming that the releasing control unit issues the release signal, the solenoid operates, the valve opens, and the alarm signals transmit.
+
+### For pre-action systems the test shall confirm that water reaches the inspector's test connection at the most remote point.
+
+### For double-interlock pre-action and deluge systems the measured water delivery time from operation to discharge shall not exceed 60 seconds, consistent with the dry-pipe water delivery rule.
+
```datasheet
label: Maximum Water Delivery Time at Trip Test
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```
+### Where the field-measured time exceeds the calculated value the cause shall be investigated and corrected.
+
+### The full releasing matrix shall be verified — each initiating device or zone, the cross-zoned logic, each releasing output, and each interlock (HVAC shutdown, damper, equipment power-down) — and the results recorded.
+
```datasheet
label: Trip Test Scope
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```
−### The pre-action or deluge valve shall be trip-tested by operating the detection system (and, for double-interlock systems, also venting the supervisory air) and confirming that the releasing control unit issues the release signal, the solenoid operates, the valve opens, and the alarm signals transmit.
−
−### For pre-action systems the test shall confirm that water reaches the inspector's test connection at the most remote point.
−
−### For double-interlock pre-action and deluge systems the measured water delivery time from operation to discharge shall not exceed 60 seconds, consistent with the dry-pipe water delivery rule.
−
−### Where the field-measured time exceeds the calculated value the cause shall be investigated and corrected.
−
−### The full releasing matrix shall be verified — each initiating device or zone, the cross-zoned logic, each releasing output, and each interlock (HVAC shutdown, damper, equipment power-down) — and the results recorded.
−
## Partial-Flow and Solenoid Tests {toc}
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min: 10
max: 180
− setpoints: [20, 30, 40, 50, 60, 70, 80, 100, 120, 150]
+ setpoints: [10, 20, 30, 40, 50, 60, 70, 80, 100, 120, 150, 180]
default: 50
```
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## Seismic joint failure is especially consequential on these systems because loss of supervisory air or damage to the releasing/pilot lines can produce a trouble condition or, on a single-interlock system already in the released state, an unintended discharge. {note}
+## Hangers shall be listed for fire protection use and installed per NFPA 13 Chapter 17, sized for the water-filled pipe weight because the pipe fills with water during hydrostatic testing and after every release.
+
+## Where the building is in Seismic Design Category C, D, E, or F per ASCE 7 and the IBC, lateral and longitudinal seismic bracing shall be provided per NFPA 13 Chapter 18, with flexible couplings at the prescribed locations.
+
```datasheet
label: Seismic Design Category
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```
−## Hangers shall be listed for fire protection use and installed per NFPA 13 Chapter 17, sized for the water-filled pipe weight because the pipe fills with water during hydrostatic testing and after every release.
−
−## Where the building is in Seismic Design Category C, D, E, or F per ASCE 7 and the IBC, lateral and longitudinal seismic bracing shall be provided per NFPA 13 Chapter 18, with flexible couplings at the prescribed locations.
−
# Delivery, Storage, and Handling {toc}
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## The Owner shall maintain a service agreement with qualified fire protection and fire alarm service contractors, and records of all inspections and tests shall be retained on-site and available to the AHJ.