A smoke extraction fan specification is a life-safety document, not a ventilation selection. The fan must move hot smoke and remain structurally sound for a defined period while people evacuate and the fire service works. Most specification failures come from treating it as an ordinary axial fan with a higher temperature label. These seven checks cover the points that decide whether the fan you order will pass inspection and perform on the day it is needed.
1. Confirm the Duty Temperature and Duration
The applicable Chinese fire code requires smoke exhaust fans to operate at 280°C for 30 minutes, with higher ratings required for special zones. Establish this figure before anything else and confirm it with the authority having jurisdiction on the project. A 280 degree fan and a 400°C fan are different machines at different prices. Ordering on the assumption that 280°C is always sufficient, when the zone requires more, is an expensive correction later.
2. Match the Motor Rating to the Duty
The temperature rating of a fan is limited by its weakest component, and that is usually the motor. SINDFAN fire-rated axial fan motors are rated from 250°C/1 hour up to 400°C/1 hour. The motor rating must cover the required duty temperature and duration with margin. Also check where the motor sits relative to the hot airstream, since an in-duct motor sees higher temperatures than one mounted outside the casing.
3. Check Blade Material, and Never Substitute
SINDFAN fire-rated axial fans use cast aluminium LM6 blades. GRP blades have a practical ceiling of roughly 70°C and nylon roughly 150°C; both soften, distort or fail well below smoke extraction temperatures. If a quotation for a 280 degree fan or a higher-rated unit lists GRP or nylon impellers, it is not a fire-rated axial fan. Verify the blade material on the submittal drawing, not only in the sales text.
4. Verify the Casing Specification
Casing thickness affects distortion under thermal load and the integrity of the duct connection. SINDFAN fire-rated axial fan casings are 2–5 mm steel. Confirm that casing material, thickness and finish are stated on the drawing, together with flange details. A casing that buckles during the duty period can alter impeller tip clearance or break the duct joint.
5. Ask How Performance Was Tested
Performance should be stated on the basis of AMCA 210/ISO 5801 testing. Request the test basis and the curves, and confirm whether airflow is quoted at ambient or at the elevated duty temperature. Hot smoke has a different density, so a curve valid at 20°C is not the same as one at 280°C. Selection for smoke duty should reflect the mass flow the system must move, not just a nominal volume figure.
6. Review Installation and Interfaces
A temperature rating only holds if the installation supports it. Check supports and hangers, expansion allowance, clearance to combustible materials, duct and damper ratings, flexible connections, and the temperature rating of cables and terminals. Confirm whether the fan runs on emergency power and how it is triggered. Plan access for inspection and cleaning at this stage rather than after commissioning.
7. Obtain Documentation Before Ordering
Ask for performance data, material and motor specifications, the duty rating and the nameplate marking before you place the order. These documents are what the inspector and the commissioning engineer will work from. If a supplier cannot state the motor rating, blade material and casing thickness in writing, that is itself the answer you need.
Send Us Your Duty
If you are preparing a smoke extraction fan specification, send SINDFAN the duty temperature and duration, required airflow, static pressure, duct size, mounting arrangement and power supply. We will confirm the suitable rating and configuration from our fire-rated axial fan range. Contact us on WhatsApp +852 9524 8434 or email info@sind-tech.com.