Specification Guide
Fire Protection Engineering · 12 min read

How to Specify a Butterfly Valve for Fire Sprinkler Systems: A Complete Checklist

Butterfly valves are the standard isolation valve for fire suppression systems — but specifying them correctly requires getting eight distinct parameters right. Miss one, and the valve may not pass authority review, fail commissioning testing, or leave the system legally non-compliant. This guide walks through every parameter with the correct specification for NFPA 13 and GB 50084 systems.

A fire suppression system butterfly valve is not a general industrial butterfly valve. It is a purpose-designed, third-party certified component that must meet specific performance requirements for flow capacity, shutoff tightness, supervisory signalling, and long-term reliability in a safety-critical application. Substituting a general industrial valve — even one from a reputable manufacturer — for a certified fire protection valve is a code violation that will be caught at inspection.

This guide is structured as a parameter-by-parameter specification checklist. For each parameter, we provide the correct specification for standard NFPA 13 and GB 50084 fire sprinkler installations, the common errors that cause rejection, and the CA-FIRE model that meets the requirement. At the end, a complete ready-to-use specification clause and RFQ checklist are provided.

1. Why Correct Specification Matters

The consequences of incorrectly specified fire protection butterfly valves fall into three categories:

Authority Rejection
Non-certified valves fail AHJ (Authority Having Jurisdiction) or insurance inspection. Valves must be replaced before the system can be accepted — expensive rework on a completed installation.
Commissioning Failure
A valve without an integrated tamper switch cannot be supervised. A valve without the correct pressure rating may not hold the hydrostatic test pressure. Both failures require replacement before sign-off.
Legal Liability
If a fire occurs and the suppression system fails to operate due to a non-compliant valve, the specifier, installer, and building owner all carry legal and insurance liability. Correct specification from the outset eliminates this risk.

Parameter 1: Certification Standard

This is the non-negotiable starting point. Fire protection butterfly valves must carry third-party certification from a recognised testing authority confirming they meet the performance requirements for fire service use. General industrial valve certification (e.g. CE marking alone, ISO 5752 dimensional compliance) is not sufficient.

Standard Authority Application Notes
GB 5135.13 CNCA / MPS (China) Required for all fire systems in China Signal butterfly valve standard. Covers tamper switch, pressure rating, seat tightness, and temperature range. CA-FIRE’s primary certification.
UL 1091 UL (USA) Required for NFPA 13 systems in USA and many international projects Butterfly valves for fire protection service. Specifiers on international projects often require UL-equivalent construction even outside USA.
FM 1112 FM Global (USA/International) Required for FM-approved systems FM approval is often required by property insurers on high-value industrial and commercial projects worldwide.
EN 1074-2 CE / Notified Body (EU) European projects Valves for water supply. CE marking alone is insufficient — must be accompanied by fire system testing to EN 12845 or national equivalent.
Common error: Specifying “butterfly valve to ISO 5752” without requiring GB 5135.13 or UL/FM certification. ISO 5752 is a dimensional standard only — it says nothing about pressure rating, seat tightness, or supervisory switch performance for fire service. Always specify the fire-specific certification standard.

Parameter 2: Pressure Rating

Fire protection butterfly valves must be rated for three distinct pressure conditions, all of which must be stated in the specification:

Working pressure (PN)1.6 MPa (PN16 / 16 bar / 232 psi) — Covers all standard NFPA 13 and GB 50084 fire system designs
Strength test pressure6.4 MPa (4× working pressure) — Hydrostatic shell test — valve body must not leak or deform
Seal test pressure3.2 MPa (2× working pressure) — Seat tightness test — zero leakage at closed disc
Minimum test pressure (system)1.2× working pressure per NFPA 13 §24.2 — System hydrostatic test after installation

Most fire protection projects specify PN16 (1.6 MPa) working pressure. This is the rating of all CA-FIRE fire protection butterfly valves. If the system design working pressure exceeds 1.6 MPa — unusual for standard sprinkler systems but possible on high-rise buildings with boosted fire mains — a high-performance double-offset butterfly valve or alternative valve type must be specified.

Parameter 3: DN Size Range

Specify the full DN range required for the project rather than individual sizes, and confirm the supplier can provide all sizes from a single certified product family. Mixing certified and uncertified sizes from different manufacturers adds procurement and documentation complexity.

System Location Typical DN Range Recommended Actuator CA-FIRE Models
Branch zone isolation DN50–DN80 Lever handle ZSXDF7-S / ZSDF7-S
Zone control assembly DN80–DN150 Lever (DN80–DN100) or gear (DN100–DN150) ZSXDF7-S / ZSXDF7
Floor riser isolation DN150–DN200 Gear (worm handwheel) ZSXDF7 / ZSDF7
Main riser / pump suction DN200–DN300 Gear (worm handwheel) ZSXDF7 / ZSDF7
Grooved pipe systems (any location) DN50–DN300 Lever (DN50–DN100) or gear (DN100–DN300) ZSXDF8 / ZSDF8 series

Parameter 4: Connection Type

Connection type must match the pipe system design. Specifying the wrong connection type requires either valve replacement or installation of transition pieces — both avoidable with correct upfront specification.

Wafer (Flanged) — specify when:
  • Pipe system uses ANSI/ASME, EN 1092, or GB/T 9113 flanges
  • Face-to-face dimension must comply with EN 558 Series 20
  • Both pipe ends will always be present (no dead-end service)
  • Models: ZSDF7 / ZSXDF7, ZSDF7-S / ZSXDF7-S
Grooved (Victaulic) — specify when:
  • Pipe system uses roll-groove or cut-groove pipe ends with Victaulic-style couplings
  • Faster installation speed is a priority
  • Some pipe movement or flexibility is required at the valve location
  • Models: ZSDF8 / ZSXDF8 / ZSDF8-S / ZSXDF8-S

Parameter 5: Actuator Type

Actuator type should be specified explicitly — do not leave it to supplier discretion. The correct actuator depends on DN size, operating torque, and operational requirements. See the actuator comparison guide for full detail.

DN50–DN100:Lever handle actuator with lockable detent plate — Quarter-turn, direct manual operation
DN125–DN300:Worm gear handwheel actuator — Self-locking; 10–15 turns to complete stroke
DN200–DN300 (frequent operation):Consider electric actuator — If the valve is operated more than monthly, gear handwheel is adequate; for more frequent use, electric actuator reduces operator fatigue
Hazardous area (Zone 1/2):Explosion-proof actuator only — NEPSI / ATEX / IECEx certified — see Parameter 8
Torque note: For DN125 and above at 1.6 MPa, break-to-open torque exceeds comfortable lever handle operation. Specifying a lever handle on DN150 is technically possible (CA-FIRE ZSXDF7-S covers to DN150) but the operator must be capable of applying the required peak force. For most projects, specify gear actuator from DN125 upwards. See the torque calculation guide for exact values.

Parameter 6: Supervisory Tamper Switch

This parameter is required on all electrically supervised fire protection systems — which means virtually every system connected to a monitored fire alarm control panel. Get this wrong and the system will fail the supervisory verification test at commissioning.

Switch type:Normally closed (NC) dry contact
Operating voltage:DC24V nominal (DC12–30V range)
Current:≤ 50 mA
Trigger point:10° ± 5° from fully open position
Response time:≤ 2 seconds (NFPA 72 requires ≤ 200 seconds)
Cable entry:PG11 gland, 2-core shielded signal cable
Enclosure:IP66 minimum
Standard:GB 5135.13 (China); UL 1091 equivalent

Specify models with tamper switch (信号型 / signal type) explicitly: ZSXDF7 (gear wafer), ZSXDF8 (gear grooved), ZSXDF7-S (lever wafer), ZSXDF8-S (lever grooved). Models without tamper switch (ZSDF7, ZSDF8, ZSDF7-S, ZSDF8-S) are for non-supervised applications only.

For complete wiring instructions, commissioning procedures, and NFPA 72 compliance details, see the tamper switch complete guide.

Parameter 7: Body, Disc & Seat Material

Material specification determines chemical compatibility, corrosion resistance, and service life. The standard specification for fire protection covers the majority of installations; alternatives are noted for specific environments.

Component Standard Specification Alternative When to Specify Alternative
Body GGG40 ductile iron, epoxy coated SS316 stainless steel Coastal/marine environments, chemically aggressive water, or where stainless pipe system requires matching valve material
Disc Ductile iron, epoxy coated or nickel-plated SS316 disc Same as above — specify SS316 disc with GGG40 body for a cost-effective corrosion upgrade
Seat EPDM (mandatory for fire protection) PTFE (special cases only) Non-AFFF foam systems with chemical incompatibility with EPDM; confirm with system designer
Stem SS410 stainless steel SS316 Aggressive water chemistry or direct seawater contact
Stem bushings Self-lubricating PTFE-bronze composite — Standard — no alternative required for fire protection service
Do not specify NBR, Neoprene, or Viton seats for fire protection: Only EPDM is certified for fire system service (potable water + AFFF foam compatibility) under GB 5135.13 and UL 1091. See the seat material guide for full chemical compatibility data.

Parameter 8: Hazardous Area Classification

If any part of the fire water system is installed in a classified hazardous area — Zone 1, Zone 2 (gas/vapour), Zone 21, or Zone 22 (combustible dust) — the butterfly valve actuator and all electrical components (including the tamper switch) must carry appropriate explosion-proof certification. Standard valves — including standard IP66 tamper switches — are not permitted in classified zones.

Hazardous Area — Specify:

CA-FIRE Explosion-Proof Series (ZSXDF7/8 Ex)

Certification: NEPSI GB 3836
Ex marking: Ex db IIC T6 Gb (Zone 1/2 gas)
Ex marking: Ex tb IIIC T80°C Db (Zone 21/22 dust)
IP rating: IP66
Suitable zones: Zone 1, Zone 2, Zone 21, Zone 22

Typical Hazardous Area Applications:
  • Petrochemical plant fire water systems
  • Offshore platform and FPSO fire protection
  • Paint shop and solvent storage fire suppression
  • Fuel terminal and aircraft hangar systems
  • Coal handling and mining fire protection

9. Ready-to-Use Specification Text

The following specification clauses can be incorporated directly into project technical specifications, tender documents, or material requisition sheets. Two versions are provided — standard (non-hazardous) and explosion-proof (hazardous area).

Version A — Standard Fire Protection Butterfly Valve (Non-Hazardous Area)

Specification Clause — Copy & Adapt

Fire Protection Butterfly Valve — Standard Type

Certification: GB 5135.13 (China) / UL 1091 equivalent
Valve type: Concentric resilient-seated butterfly valve, wafer [or grooved] connection
Working pressure: PN16 (1.6 MPa)
Strength test: 6.4 MPa (hydrostatic shell test, zero leakage)
Seal test: 3.2 MPa (seat tightness test, zero leakage)
DN range: DN[__] to DN[__] [specify per schedule]
Body material: GGG40 ductile iron, epoxy coated [or SS316 if specified]
Disc material: Ductile iron, epoxy coated [or SS316]
Seat material: EPDM (mandatory — no substitution)
Stem material: SS410 stainless steel
Actuator — DN50 to DN100: Lever handle with lockable detent plate
Actuator — DN125 to DN300: Worm gear handwheel, self-locking
Supervisory switch: Integrated DC24V tamper switch, normally closed contact,
trigger point 10° ±5° from fully open, IP66, PG11 cable entry
Model designation (with switch): ZSXDF7 [wafer] / ZSXDF8 [grooved]
Model designation (without switch, non-supervised zones): ZSDF7 / ZSDF8
Operating temperature: 0°C to +80°C (switch version); −10°C to +80°C (non-switch)
Face-to-face: EN 558 Series 20 [wafer] / per Victaulic C606 [grooved]
Manufacturer: CA-FIRE Protection Co., Ltd., Nan’an, Fujian, China
Website: www.ca-fire.com | Enquiries: sales@ca-fire.com

Version B — Explosion-Proof Fire Protection Butterfly Valve (Hazardous Area)

Specification Clause — Hazardous Area Version

Fire Protection Butterfly Valve — Explosion-Proof Type

As Version A above, plus:
Hazardous area certification: NEPSI GB 3836
Ex marking (gas/vapour): Ex db IIC T6 Gb (Zone 1 and Zone 2)
Ex marking (dust): Ex tb IIIC T80°C Db (Zone 21 and Zone 22)
IP rating: IP66
Tamper switch: Explosion-proof DC24V NC switch, Ex-certified,
integrated in Ex-rated actuator housing
Model designation: ZSXDF7 Ex [wafer] / ZSXDF8 Ex [grooved]
(DN50–DN300, 1.6 MPa, EPDM seat, GGG40 or SS316 body)
Manufacturer: CA-FIRE Protection Co., Ltd.
Website: www.ca-fire.com | Enquiries: sales@ca-fire.com

10. RFQ Checklist for Procurement

When submitting a request for quotation to butterfly valve suppliers, include the following information to ensure you receive comparable, compliant quotations. Missing information typically results in suppliers quoting the cheapest non-compliant option.

Procurement Checklist — Fire Protection Butterfly Valves
Certification standard required — GB 5135.13, UL 1091, FM 1112, or EN 12845 equivalent — state which
DN schedule — List all sizes required, e.g. DN50 × 10 pcs, DN100 × 6 pcs, DN150 × 4 pcs
Connection type — Wafer (flanged) or grooved (Victaulic-compatible) — or both
Working pressure — PN16 / 1.6 MPa for standard systems
Actuator type per DN range — Lever (DN50–DN100) / gear (DN125–DN300) — or specify otherwise
Supervisory switch required? — Yes (ZSXDF models) or No (ZSDF models) — confirm for each DN range
Body material — GGG40 (standard) or SS316 (corrosive environments)
Seat material — EPDM (mandatory for fire protection — do not accept alternatives without engineer approval)
Hazardous area classification — Non-hazardous (standard) or Zone 1/2/21/22 (explosion-proof NEPSI/ATEX required)
Required documentation — GB 5135.13 certificate, material certificates (EN 10204 3.1), pressure test certificates, tamper switch wiring diagram
Delivery requirements — Lead time, packing, shipping terms (FOB Xiamen / CIF destination)
Project name and end use — Allows supplier to confirm correct model and provide application-specific technical support
Send your schedule to CA-FIRE: Email your DN schedule, connection type, and supervisory requirement to sales@ca-fire.com — we will provide a line-item quotation with certified model numbers, lead times, and documentation list within one business day. For grooved systems, also specify your groove standard (AWWA C606 / ISO 6182).

Complete CA-FIRE Technical Guide Series

CA-FIRE Protection · 川安消防实业有限公司

Ready to Submit Your RFQ?

Send your DN schedule, connection type, and project details — we respond with a complete line-item quotation, certified model numbers, and documentation list within one business day.

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