ISO 13373-5:2020

Overview

ISO 13373-5:2020 - Condition monitoring and diagnostics of machines - Vibration condition monitoring - Part 5: Diagnostic techniques for fans and blowers provides a practical, vibration-based methodology for diagnosing vibration faults specifically in fans and blowers. Intended for condition monitoring practitioners, engineers and technicians, the standard lays out step‑by‑step diagnostic procedures, diagnostic flow charts, process tables and fault tables with examples for common fan and blower designs.

Key topics and technical requirements

• Scope and purpose: Focuses on vibration diagnostics performed after an anomaly has been detected (diagnostics following monitoring).
• Measurement guidance: Describes appropriate vibration transducers and measurements:
  • Non‑contacting probes (inductive, capacitive, eddy current) for rotating shafts.
  • Seismic transducers (accelerometers, velocity sensors) for non‑rotating parts such as bearing housings.
• Operational parameter capture: Emphasises recording rotational speed, load, fan orientation (vertical/horizontal), mounting configuration and temperatures as part of diagnosis.
• Initial analysis: Calls for an initial assessment (safety, vibration severity, history, operating effects) aligned with ISO 13373‑3 practices.
• Systematic diagnostic tools:
  • Fault tables (Annex A) listing common faults and vibration signatures (e.g., unbalance, misalignment, looseness, soft foot, casing distortion).
  • Methodology (Annex B) providing a structured, step‑by‑step approach.
  • Worked examples (Annex C) illustrating fault identification for different fan/blower types.
• Limitations: Bearing‑specific vibration faults (hydrodynamic or rolling element) are referenced to ISO 13373‑3 and are not the primary focus of this part.
• Recommended actions: The standard does not prescribe corrective actions for every scenario - actions depend on confidence in diagnosis, practitioner experience, fault severity, safety and commercial considerations.

Practical applications and users

Who benefits:

• Condition monitoring teams and vibration analysts
• Maintenance engineers and reliability technicians
• Predictive maintenance program managers

Typical applications:

• Root cause analysis for excessive fan or blower vibration
• Onsite troubleshooting using vibration signatures and operational data
• Integrating vibration diagnostics into predictive maintenance and reliability programs
• Training and standardising diagnostic workflows across plants

Related standards

• ISO 13373 series (Parts 1, 2, 3) - general procedures, signal processing and vibration diagnosis
• ISO 7919, ISO 10816, ISO 20816 - vibration severity assessment
• ISO 2041, ISO 13372 - terminology
• ISO 21940‑2 - rotor balancing vocabulary
• Design guidance: ISO 14694, ISO 14695, VDI 3839 Part 4 (fan designs)

ISO 13373-5:2020 is a practical, field‑oriented standard for improving vibration condition monitoring, fault diagnosis, and the reliability of industrial fans and blowers.