Every duct that passes through a fire-rated wall or floor makes an opening in that barrier. A fire damper closes that opening in a fire. This guide explains the two fire damper models we supply, how they differ, and which documents a Qatar project needs for them.
What a fire damper does
The FD-SL datasheet describes the job: the damper uses a frame and curtain-style blades to prevent the spread of fire through a penetration in a fire-rated barrier made by an HVAC duct or transfer opening. In normal operation the curtain blades are held open as a folded stack.
On a curtain fire damper, a fusible link holds the folded blades. When the link reaches its rated temperature it releases, and the curtain closes the opening. An access panel is required so that the damper can be inspected and reset periodically.
Static curtain or motorised dynamic
The main difference is whether the ventilation fans keep running in a fire. In a static system the fans turn off; in a dynamic system they stay on.
FD-SL static curtain fire damper
Slimline frame with curtain blades and a fusible link, for static HVAC systems only (fans off in a fire).
FDD-MB-3V(M) motorised fire damper
Multi-blade damper with 3V blades and an actuator, for dynamic systems (fans on in a fire) and also static systems.
| Datasheet item | FD-SL | FDD-MB-3V(M) |
|---|---|---|
| Fire rating | UL 555 classified, 1.5 or 3 hours | UL 555 classified, 1.5 or 3 hours |
| System | Static only (fans off in a fire) | Dynamic (fans on in a fire), also static |
| Blades | Curtain blades, 22-gauge galvanized steel | 3V blades, 16-gauge galvanized steel |
| Frame | 22-gauge galvanized roll-formed steel | 20-gauge roll-formed steel hat section |
| Free area | Type A about 75–85 %; Type B (blades out of the airstream) about 80–90 % | Pressure drop tested by an independent laboratory to AMCA 500-D, Fig. 5.3 |
| Limits | Installed vertically or horizontally | Maximum velocity 2000 fpm (10.2 m/s); maximum pressure 4 in wg (1 kPa) |
| Fusible link / heat-responsive device | 165 °F (74 °C) standard; 212 °F (100 °C) optional | Electric thermostat 165 °F (74 °C); 212 °F (100 °C) optional |
| Minimum size | Type A 4×4" (102×102 mm); Type B 4×3" (102×76 mm) | 6×6" (152×152 mm) |
| Frame depth | 2-3/8" (55 mm) | 5" (127 mm) |
On the motorised damper, the product page lists an electric actuator with fail-safe spring return to closed, 24 V DC or 230 V AC options, and integration with the BMS and the fire alarm system, including open/closed position feedback.
The fire damper page adds that the range comes in curtain-blade or multi-blade designs. The FD-SL datasheet specifies a 22 gauge galvanized roll-formed steel frame and blades with a stainless-steel closure spring, and offers stainless steel construction as an option.
Installation points from the datasheets
- FD-SL: can be installed vertically or horizontally; an external sleeve can be factory-installed.
- FD-SL datasheet: Type A from 4×4" (102×102 mm) and Type B from 4×3" (102×76 mm); the largest vertical single section is 60×60" (1524×1524 mm) for Type A and 60×55" (1524×1397 mm) for Type B at 1½ hours; retaining angles (16 ga × 1½ × 1½") are an option.
- FDD-MB-3V(M): the blade closure line must lie within the plane of the fire-rated wall or floor, and the damper is not approved with the blades running vertically.
- FDD-MB-3V(M): the suggested sleeve depth is 16 in (406 mm) for walls up to 6 in (152 mm) thick with mounting angles on both sides; add 1 in for each extra inch of wall.
- Fire damper page: an access panel is required for periodic inspection and reset.
Qatar approval: Civil Defence and QCS 2024
For a project in Qatar, the fire rating alone is not enough for the submittal. The fire dampers we supply are registered with Qatar Civil Defence, and our dampers comply with QCS 2024. The UL 555 listings printed on both datasheets include a listing for Qatar (R40068), and both datasheets list the standards met: NFPA 80, 90A, 92A, 92B and 101, and the ICC International Building Code.
What to ask your supplier for
Before you order fire dampers for a Qatar project, ask the supplier for three documents and check them against your drawings:
- The product datasheet, showing the UL 555 classification and the fire rating (1.5 or 3 hours) that your wall or floor needs.
- A compliance statement for QCS 2024.
- The Qatar Civil Defence registration document.
Send your damper schedule or BOQ through the quote form for a formal quotation within 4 business hours, and request the documents with it. The submittal page also covers UL certificates and shop drawings for your project.