Vibration, overheating, and airflow loss are the three symptoms that account for 80 percent of the radial-blade fan service calls we receive from hospital & cleanroom facilities in Thailand. Each symptom has a different diagnostic path, and choosing the wrong path wastes time and money.
Problem: Unusual Noise
New or changing noise from a radial-blade fan in a hospital & cleanroom facility almost always indicates a developing problem. Broadband noise increase suggests blade fouling or erosion. Tonal noise at blade-pass frequency typically indicates system resonance or flow instability. Rattling or knocking sounds point to loose components or foreign objects in the airstream.
If the noise level exceeds the 35 to 45 dB(A) specification, inspect the impeller, check clearances between the impeller and housing, and verify that inlet conditions are uniform. Non-uniform inlet flow is a common cause of tonal noise that does not appear on the factory test curve.
Keruite's field engineers in Thailand have observed that radial-blade fan systems in hospital & cleanroom applications often operate at conditions different from what was assumed during design. The most common discrepancy is system resistance: actual duct pressure drop frequently exceeds the calculated value by 10 to 25 percent. This is why we recommend including a 10 percent safety margin on static pressure and verifying the operating point during commissioning against the certified performance curve.
Problem: High Motor Current
A radial-blade fan drawing higher motor current than the commissioning baseline has either increased system resistance or a mechanical problem. The diagnostic process starts with measuring the operating point: if airflow is lower than baseline at higher pressure, the duct system has changed. If airflow is at or above baseline but current is still high, check the impeller for fouling (added weight increases power demand).
In hospital & cleanroom applications in Thailand, the most common cause of gradually increasing motor current is filter loading. Replacing clogged filters can reduce motor current by 10 to 15 percent and bring the operating point back to design.
In practice, this means that hospital & cleanroom facilities in Thailand should establish a clear specification document before approaching vendors. The document should include the design airflow (2,000 to 15,000 m3/h), required static pressure (100 to 500 Pa), operating temperature range (-20 to 40 C), material preference (stainless steel 316L), noise limits (35 to 45 dB(A)), and any certification requirements (AMCA, ISO 9001). Projects that skip this step typically experience 20 to 30 percent more change orders during installation, which drives up costs and delays commissioning.
Problem: Intermittent Shutdowns
If a radial-blade fan trips off periodically but restarts without any apparent problem, the most likely causes are motor overload (triggered by high current during transient conditions), VFD fault (caused by power quality issues or parameter misconfiguration), or a safety interlock that is being triggered by an unrelated system.
Check the fault log on the VFD and the motor protection relay. In hospital & cleanroom facilities in Thailand, we frequently find that the motor overload setting was left at the default value rather than being adjusted for the actual operating current. Setting it correctly typically resolves intermittent trip issues.
Energy consumption is the single largest operating cost for a radial-blade fan in a hospital & cleanroom facility. Over a 15-year equipment life, energy costs typically exceed the initial purchase price by a factor of 5 to 8. This means that even small efficiency improvements โ selecting an IE1 motor instead of a lower class, optimizing the duct design to reduce system resistance, or installing a VFD for variable load applications โ compound into significant financial savings over time.
| Parameter | Specification |
| Airflow Range | 2,000 to 15,000 m3/h |
| Static Pressure | 100 to 500 Pa |
| Motor Power | 22 kW (IE1) |
| Material | stainless steel 316L |
| Temperature Range | -20 to 40 C |
| Impeller Balance | G2.5 (ISO 1940) |
| Noise Level | 35 to 45 dB(A) |
| Certifications | AMCA, ISO 9001 |
| Standards | HTM 03-01, ASHRAE 90.1 |
Quality Assurance and Testing
Every radial-blade fan unit leaving our factory undergoes a standardized test procedure that includes a run test at full speed, vibration measurement at all bearing locations (must meet G2.5 grade), and verification of impeller balance. For units above 22 kW motor rating, we also perform a witnessed performance test on the AMCA-standard test rig, measuring airflow, pressure, and power consumption at three operating points.
Field testing after installation should replicate key factory measurements to establish the commissioning baseline. The measured airflow and pressure should be within 5 percent of design values. All commissioning data should be documented and retained as part of the project quality records.
Procurement and Lead Time Planning
For hospital & cleanroom projects specifying radial-blade fan equipment in Thailand, procurement should begin 12 to 16 weeks before the required delivery date for standard configurations (stainless steel 316L construction, AMCA certified). Custom specifications such as special materials or multiple certifications (AMCA and ISO 9001) may extend lead times to 20 weeks.
When requesting quotations, provide the complete specification including airflow (2,000 to 15,000 m3/h), pressure (100 to 500 Pa), operating temperature (-20 to 40 C), noise requirement (35 to 45 dB(A)), and certification requirements. Incomplete specifications lead to assumptions that may not match actual site conditions.
Conclusion
From specification to long-term operation, a radial-blade fan in a hospital & cleanroom application performs best when the engineering basics are done right. The data and practices shared in this article come from our 28 years of manufacturing and field experience. the company's engineering team in Thailand is ready to support your next project.