Choosing an axial fan is not about picking the cheapest catalogue item — it is about matching three things: duty, environment and installation. Get them right and the fan runs quietly for years; get them wrong and you are replacing bearings or motors within months.
Step 1 — Define the duty: flow and pressure
Every fan is selected on two numbers: airflow (m³/h or CFM) and system pressure (Pa or mmH₂O). For ducted systems the pressure requirement comes from duct friction, bends, filters and dampers. A common mistake is choosing a fan that delivers flow but not enough pressure — the result is dramatically reduced airflow in the real system.
SINDFAN publishes full performance curves (AMCA 210 / ISO 5801 tested) so your engineer can verify the operating point before ordering — not after installation.
Step 2 — Match blade material to the environment
| GRP (glass-reinforced plastic) | −40 to +70°C. Corrosion-resistant — first choice for marine air, chemical plants and agricultural buildings with ammonia. |
| Nylon66 (GRN) | −40 to +150°C. Tough, fatigue-resistant, handles hot exhaust and frequent cycling. |
| Cast aluminium LM6 | Fire-rated duty up to 400°C for smoke extraction. Also the standard for high-speed impellers. |
| Anti-static GRN-ATI | For explosion-risk zones (paired with Ex-rated motors). |
Step 3 — Check the installation
- Roof or wall mounted? Roof axial fans need weather protection; wall units need correct discharge direction.
- Ducted or free-air? A free-air fan is usually smaller than a ducted unit for the same duty.
- Fire rating needed? Smoke-extraction fans are specified by temperature class and duration (e.g. 300°C/2h, 400°C/2h) — never substitute a standard fan.
- Speed control? Variable-speed duty changes the motor specification — tell your supplier from day one.
Balance quality matters more than you think
A poorly balanced rotor vibrates, wears bearings and shortens motor life. SINDFAN balances every rotor to ISO 1940-1 G4.0 and includes the balance report with delivery. When you compare quotes, ask for the balance grade — it is a reliable indicator of build quality.
Need a fan? Send us your duty (flow + pressure) or a photo of the existing unit. WhatsApp +852 9524 8434 — quote within 24 hours.