The role of acoustic and vibration monitoring in equipment reliability

Publish Date • 11 February 2026

According to the U.S. Department of Energy, the average capacity of newly installed wind turbines in 2023 reached 3.4 MW, up 5% from 2022 and a 375% increase since 1998. The larger and more powerful these technologies grow, the higher the operational stakes. A single blade failure can cost tens of thousands of dollars to repair and carry high replacement costs, especially when considering supply chain challenges. Across industrial sectors, downtime is becoming more expensive: Nearly 30% of facilities report rising unplanned downtime costs averaging a staggering $25,000 per hour.

Condition monitoring devices can play a critical role in identifying mechanical issues before they escalate into expensive operational interruptions. For these tools to be effective, they must perform reliably in the environments where rotating machinery and turbine components operate — environments subject to weather exposure, electromagnetic interference, and constant mechanical stress.

FM Approvals has published two Examination Standards that define the testing protocols used to evaluate devices that monitor the performance of wind turbines and other rotating machinery. These standards are:

Both FM 6550 and FM 6530 help ensure that devices used for monitoring the health of wind turbines and other rotating machinery perform reliably in real-world conditions, providing operators with the early insights that can potentially be used to avoid unexpected, costly equipment failures and unplanned downtime.

Wind turbines and acoustic monitoring systems

Consider what happens when a wind turbine blade starts to delaminate. On the surface, the turbine looks fine, continues to spin, and output remains steady. From the ground, everything appears normal — the turbine spins smoothly, and power output remains steady. Yet blade structure could be weakening, and potentially serious issues may be developing, undetectable without advanced monitoring. If undetected, the damage could spread. Condition monitoring allows for early scheduling of a replacement as soon as the delamination grows.

Acoustic monitoring systems help operators intervene long before a blade reaches this point, using sensors mounted on the tower or on the inside the blades which collect and interpret acoustic data for signatures of issues or abnormal operation that reveal issues unique to blade and turbine acoustics. These systems must navigate complexities, such as turbines sounding different when offshore or onshore, at different wind speeds and during rain or icing events.

Acoustic monitoring systems are designed to detect:

  • Blade delamination or cracking
  • Punctures and structural fatigue
  • Bird impacts
  • Lightning strikes
  • Abnormal changes caused by rain, wind speed or environmental conditions

When FM Approvals certifies monitoring systems are certified to FM 6550, there is confirmation that the system can reliably do the following:

  • Distinguish meaningful signals from ambient noise
  • Provide local and remote alerts (Class I and Class II systems)
  • Diagnose specific types of damage (Class III systems)
  • Continue functioning under varying environmental conditions
  • Maintain reliable performance without being adversely affected by electromagnetic disturbances
  • Transfer data securely without introducing cyber risk

Most importantly, the standard evaluates complete systems — not just the sensors — ensuring cloud applications, communication paths and alarm functions work together as intended.

Vibration and multi-sensor monitoring systems for rotating machinery

While FM 6550 is specific to the external acoustics of wind turbines, FM Approvals Examination Standard 6530, for rotating machinery, evaluates technologies designed to monitor the internal mechanical health of rotating components. This includes everything from pumps, compressors and motors to generators, gearboxes, elevators, and process automation equipment.

FM 6530 evaluates monitoring systems that use any or a combination of the following: vibration, noise or acoustics, temperature, current voltage, humidity, or partial discharge.

These systems track trends over time. A sudden or unexplained change is often the first sign of an issue. Therefore, FM 6530 evaluates whether monitoring systems can:

  • Detect and track meaningful changes
  • Avoid false alarms
  • Maintain reliable performance without being adversely affected by electromagnetic disturbances
  • Survive environmental stresses
  • Deliver local and remote alerts (Class I and Class II systems)
  • Provide diagnostic-level fault analysis (Class III systems)

FM 6530 evaluates complete condition monitoring systems to ensure they deliver reliable, precise, and actionable insights under real-world operating conditions.

How FM Approvals integrates cybersecurity into performance standards

Condition monitoring systems do far more than collect data. They often transmit information through cloud platforms, cellular networks, or facility networks to support remote diagnostics and alerting. This connectivity introduces cyber risk exposure. A monitoring device that is improperly secured can unintentionally create a path into an operator’s network or, in the case of condition monitoring equipment for wind turbines, even into the power grid.

To address this risk, FM Approvals integrates cybersecurity requirements directly into its programs for FM 6550 and FM 6530. If a monitoring system connects to an asset owner's network or if a monitoring system connects to the Supervisory Control and Data Acquisition (SCADA) network, it must demonstrate conformance with cybersecurity controls aligned with ISA/IEC 62443.

As a highly specialized and internationally recognized ISASecure® Certification Body, FM Approvals tests and certifies the conformance of industrial control systems, connected systems, and related components to the ISA/IEC 62443 standards. Certification provides assurance that a product is protected against known cyber vulnerabilities and meets industry best practices for cybersecurity.

The FM APPROVED difference in condition monitoring

Early warning is the most effective way to prevent costly machinery failures, especially as turbines and industrial equipment operate under growing mechanical and environmental stress. When a monitoring system can pinpoint the exact turbine, gearbox, or component showing abnormal behavior, maintenance teams know precisely where to go and what to address in a timely and cost-effective manner.

FM 6550 and FM 6530 help ensure condition monitoring systems deliver that level of clarity and reliability by verifying performance, durability and integrity. When selecting condition monitoring technologies, look for the FM APPROVED mark as your trusted indicator of proven, dependable performance.

Learn more about products we certify and our Examination Standards. To find listings of all FM Approved products, visit the Approval Guide.

If your organization manufactures or is in search of additional information related to acoustic and vibration monitoring equipment, contact Patrick Byrne (FM Approvals, Operations Vice President, Group Manager – Electrical Systems) at [email protected].

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