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Fire & Smoke Dampers | FHF, PFHF & PYF | YONGFAN
70 °C / 280 °C Thermal Action · GB 15930-2007 Execution Standard

Fire & Smoke Dampers: FHF, PFHF & PYF Series

Fire and smoke dampers control when duct openings stay open or close during a fire; choosing the wrong normal position or thermal action can defeat the intended smoke-control sequence.

Compare YONGFAN FHF Fire Dampers (normally open, 70 °C thermal closure), PFHF Smoke-Exhaust Fire Dampers (normally open, 280 °C thermal closure), and PYF Smoke-Exhaust Dampers (normally closed, opens on fire signal). Available in rectangular (W×H) and circular (ØD) profiles with manual, DC 24V solenoid, and motorized reset actuators.

FHF Fire DamperNormally Open · 70 °C Closure
PFHF Smoke FireNormally Open · 280 °C Closure
PYF Smoke ValveNormally Closed · Fire Signal Open
Actuation LogicManual · DC 24V · Motor Reset
Select a Fire & Smoke Damper Fire Damper Routing Table
HVAC motorized fire and smoke damper installation
Life-Safety Airside Isolation GB 15930-2007 Compliant · 70 °C / 280 °C Thermal Fusible Links · DC 24V Interlock
01 / Sequence of Operation

Fire-Damper Mistakes Begin with the Normal Operating Position

A contractor can install a damper in the correct opening, wire the actuator correctly and still defeat the life-safety sequence by confusing normal state and thermal triggers.

The first fundamental question is whether the damper should be open or closed during normal operation.

YONGFAN’s FHF and PFHF families are normally open. They allow normal ventilation until a fire-related condition causes them to close. PYF is the opposite: it is normally closed and opens only after receiving a fire signal so smoke can enter the designated mechanical exhaust path.

The second mistake is using the wrong thermal trigger. FHF closes at 70 °C to isolate HVAC fire compartments early. PFHF closes at 280 °C in active smoke-exhaust ductwork, remaining open during extraction to protect downstream exhaust fans from flashover.

The third mistake is treating the actuator as the complete fire function. Manual close, solenoid release, motorized reset, and signal feedback are distinct engineering functions that must match the building fire alarm protocol.

Commercial building mechanical smoke exhaust ductwork

ISO 21927-8:2017 addresses smoke control dampers and associated components used in pressure-differential and smoke/heat-control systems. YONGFAN’s supplied FHF/PFHF/PYF documentation references GB 15930-2007 as its execution standard.

1. Normal State Logic

FHF & PFHF are normally open (NO) for continuous air movement. PYF is normally closed (NC) and opens only on fire alarm command.

NO vs NC Normal State

2. 70 °C vs 280 °C Action

FHF isolates general ventilation partitions at 70 °C. PFHF maintains emergency smoke extraction until 280 °C limit is reached.

70 °C / 280 °C Thermal Release

3. Position Signal Feedback

Actuator variants send closed-position feedback (FHF) or open-position feedback (PYF) back to the central fire control panel.

DCS / Fire Control Integration
02 / Engineering Parameters

Normal State, Thermal Action and Actuator Logic Must Be Specified Separately

Six distinct specification fields that define the life-safety performance of the damper assembly.
Field 01

Normal State

FHF: Normally open.
PFHF: Normally open.
PYF: Normally closed.
Determines whether the component isolates a duct or establishes an exhaust path.

NO vs NC
Field 02

Thermal Action

FHF: Closes at 70 °C.
PFHF: Closes at 280 °C.
PYF: No thermal closing point; opens from NC on electrical fire signal.

70 °C · 280 °C · Fire Signal
Field 03

Control Mode

Manual (WS), DC 24V electric-solenoid (WSDc), or fully automatic motorized reset (WSDj) actuator configurations.

WS / WSDc / WSDj
Field 04

Signal Feedback

Outputs closed-position signal (FHF/PFHF) or open-position signal (PYF) for fire control system confirmation.

Position Verification
Field 05

Reset Method

Manual pull-ring/lever reset, or remote electric motor reset for hard-to-access ceiling locations.

Manual vs Motorized Reset
Field 06

Size & Material

Rectangular W×H or circular ØD. Baked-enamel steel plate, hot-dip galvanized sheet, or 304/316L stainless steel.

W×H · ØD · Galvanized / Stainless
03 / Product Architecture

Choose the Damper Family from the Fire-Control Sequence

Detailed technical features of FHF 70 °C fire dampers, PFHF 280 °C smoke-exhaust fire dampers, and PYF normally closed smoke valves.
Family 01 · 70 °C Fire Partition Isolation Normally Open · 70 °C Thermal Fuse

FHF Fire Damper for ordinary ventilation duct isolation

The FHF Fire Damper is normally open during routine building ventilation. When duct-air temperature reaches 70 °C, the fusible link melts and spring mechanism automatically closes the damper.

Installed wherever general air-conditioning or ventilation ductwork crosses fire-rated partition walls, floors, or designated fire compartments.

FHF WS-FKManual closing, 70 °C thermal action, closed feedback, 5-position adjustment
FHF WSDc-FKDC 24V solenoid remote closing + 70 °C thermal action + manual reset
FHF WSDj-FKFully automatic motorized reset via actuator motor + manual reset option
ProfilesRectangular W×H and circular ØD in steel, galvanized or stainless
View FHF Fire Dampers Request FHF Sizing
FHF 70 degree fire damper installation
FHF Series Normally Open · 70 °C Thermal Fusible Link · Fire Partition Boundary Isolation
Family 02 · 280 °C High-Temp Smoke Extract Isolation Normally Open · 280 °C Thermal Fuse

PFHF Smoke-Exhaust Fire Damper for high-temperature smoke ducts

The PFHF Smoke-Exhaust Fire Damper is installed directly in mechanical smoke-exhaust systems. It remains normally open during the initial fire sequence so high-temperature smoke can pass toward the exhaust fan.

When extracted smoke reaches 280 °C, the fusible link operates and snaps the damper shut, protecting the downstream smoke-exhaust fan (such as HTFC) and duct system from catastrophic heat damage.

PFHF WS-KManual closing, 280 °C thermal action, closed feedback, manual reset
PFHF WSDc-KDC 24V electric-solenoid remote closure + 280 °C thermal action
PFHF WSDj-KFully automatic motorized reset with 280 °C thermal closing
HTFC Fan CoordinationProtects 280 °C / 30 min smoke exhaust fans from excessive thermal shock
View PFHF Smoke Fire Dampers Request PFHF Sizing
PFHF 280 degree smoke exhaust fire damper
PFHF Series Normally Open · 280 °C High-Temp Smoke Extract · Fan Protection
Family 03 · Normally Closed Smoke Outlet Normally Closed · Opens on DC 24V Fire Command

PYF Smoke-Exhaust Damper for opening the smoke path on command

The PYF Smoke-Exhaust Damper reverses the normal-state logic of FHF and PFHF. It remains normally closed during daily occupancy.

When a fire signal is detected, the fire control center sends a DC 24V command to the actuator, opening the damper to create an exhaust path into the building smoke-control shaft. Outputs an open-position confirmation signal.

PYF SDc-K-W×HRectangular opening · DC 24V electric opening · Open feedback signal
PYF SDc-YK-BSPanel smoke-outlet with architectural grille · Manual pull-wire reset
Smoke Shaft OutletsInstalled on corridor, lobby, and basement smoke exhaust openings
Interlock LogicSends open signal to trigger starting sequence of main smoke fan
View PYF Smoke Dampers Request PYF Sizing
PYF normally closed smoke exhaust valve
PYF Series Normally Closed · Opens on DC 24V Signal · Open Confirmation Feedback
04 / Selection Matrix

Fire and Smoke Damper Routing Table

Match your system duct type, normal operating state, and thermal closing requirement directly to the correct model series.
Product Family What It Solves Range Boundary from YONGFAN Data First Input to Confirm Action
FHF Fire Damper
 Isolates ordinary ventilation ductwork at a fire boundary
Normally open; 70 °C thermal closure; rectangular W×H or circular ØD; manual/electric/motorized
 Whether the duct must close at 70 °C Configure FHF
PFHF Smoke-Exhaust Fire Damper
 Keeps a smoke-exhaust duct open until high-temperature closure is required
Normally open; 280 °C thermal closure; rectangular W×H or circular ØD; manual/electric/motorized
 Whether the damper is in an active smoke-exhaust duct Configure PFHF
PYF Smoke-Exhaust Damper
 Opens a normally closed smoke-exhaust path after a fire signal
Normally closed; opens on fire command; open-position feedback; DC 24V actuator
 Whether the opening must remain closed during normal operation Configure PYF
05 / Procurement Protocol

Fire-Damper Enquiries Should Describe the Sequence of Operation

Essential parameters to confirm before finalizing fire and smoke damper models.
Fire Damper Sizing Checklist

Key Inputs for Fire & Smoke Damper Orders

Submitting your required normal damper state, thermal action temperature, actuator control voltage, and duct physical dimensions enables our team to confirm model codes and supply certified drawings.

1. Duct Type: Normal HVAC vs Mechanical Smoke
2. Normal Position: Normally Open vs Normally Closed
3. Thermal Action: 70 °C vs 280 °C Fusible Link
4. Control Command: DC 24V Solenoid / Actuator
5. Position Signal Feedback (Closed / Open Contact)
6. Reset Method: Manual vs Remote Motorized (WSDj)
7. Duct Opening Dimensions (Rectangular W×H / Round ØD)
8. Material: Enamel Steel, Galvanized Sheet, 304/316L SS
06 / Compliance & Standards

GB 15930-2007 Execution Standard and Quality Control

Governed under GB 15930-2007 standard for building ventilation and smoke-exhaust fire dampers.
Execution Standard

GB 15930-2007 Standard

FHF, PFHF, and PYF are manufactured against GB 15930-2007 (Fire dampers for building ventilation and smoke-exhaust systems).

Actuation Verification

Thermal & Electrical Release

Fusible link operating temperatures (70 °C and 280 °C) and DC 24V solenoid trigger mechanisms are verified for positive mechanical closure.

Project Submittals

Drawing & Material Schedules

Approved factory submittal drawings, actuator wiring diagrams, and material schedules provided for fire authority project review.

Compliance Disclosure: GB 15930-2007 is the documented national standard. For international projects requiring EN 1366-2, ISO 21927-8, or UL 555 certifications, confirm exact project documentation requirements.
07 / Architectural Boundaries

Fire Dampers Cannot Be Selected as Ordinary Duct Accessories

FHF, PFHF and PYF are part of the building fire and smoke-control sequence.

FHF vs PFHF Thermal Action

Do not use FHF where the smoke-exhaust duct must remain open to 280 °C. FHF would close prematurely at 70 °C and choke smoke extraction.

70 °C vs 280 °C Function

PFHF vs PYF Normal Position

Do not use PFHF as a substitute for a normally closed smoke outlet. PFHF is normally open and cannot keep smoke shafts isolated during daily operation.

Normally Open vs Normally Closed

Fire Sequence Sizing Link

The correct product is determined by normal position, emergency action, thermal trigger, feedback and reset logic before duct size and material are finalized.

Life-Safety Sequence Check
ALERTS — NOT PART OF THE PAGE. RESOLVE BEFORE PUBLISHING.
Supplier credibility evidence is insufficient for the required five-part audit: the retrieved fire-valve source does not confirm manufacturing location, batch release testing, application laboratory or family-specific supply-continuity data.
The source states GB 15930-2007 as the execution standard but does not provide certificate numbers or third-party test reports for each FHF/PFHF/PYF configuration. Confirm current documents before publication.
The source distinguishes WSDc and WSDj actuator arrangements, but full actuator model mapping varies by product. Do not generalize one reset or feedback function to every FHF/PFHF/PYF actuator code.
Do not present GB 15930 compliance as EN, ISO, UL or another market approval without the corresponding certificate.
08 / Technical Q&A

Fire & Smoke Dampers Frequently Asked Questions

Direct engineering answers covering 70 °C vs 280 °C triggers, NO vs NC states, position feedback, and profiles.

Which YONGFAN damper closes at 70 °C?

Use the FHF Fire Damper. It is normally open and the documented fusible element closes the damper when duct-air temperature reaches 70 °C.

Which damper closes at 280 °C?

Use the PFHF Smoke-Exhaust Fire Damper. It remains normally open in the smoke-exhaust duct and closes thermally at 280 °C.

Which YONGFAN damper is normally closed?

The PYF Smoke-Exhaust Damper is normally closed and opens after a fire-control command to establish the smoke-exhaust path.

Which family should be used where normal HVAC duct crosses a fire partition?

Start with FHF. Its documented role is ordinary ventilation duct isolation at fire-partition walls or floors.

Which family belongs in a mechanical smoke-exhaust duct?

Use PFHF where the duct should stay open for smoke extraction until the 280 °C thermal condition is reached. Use PYF where the smoke outlet should remain closed until commanded open.

Which products can send position feedback?

The supplied FHF configurations can output a closed-position signal, while PYF configurations can output an open-position signal.

Are rectangular and circular fire dampers available?

Yes. The FHF and PFHF documentation supports rectangular W×H and circular ØD configurations.

Does GB 15930-2007 mean the damper is automatically approved for another country?

No. FHF, PFHF and PYF are documented against GB 15930-2007. Projects requiring another national approval should request the exact corresponding certificate.

09 / Application Engineering Handoff

Select a Fire & Smoke Damper

Connect normal position, emergency action, thermal trigger, feedback and reset logic into one confirmed configuration. Send your fire safety schedules to our application engineers.

FHF Fire Damper (70 °C) PFHF Smoke Fire (280 °C) PYF Smoke Valve (NC) DC 24V Solenoid Motorized Reset (WSDj) Rectangular W×H Circular ØD
Select a Fire & Smoke Damper Go to Selection Center Ask an HVAC Engineer
YONGFAN application engineers reviewing fire and smoke damper submittals
Direct Technical Selection Support
Fusible link ratings, actuator wiring schematics, and dimensioned CAD submittals.
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