Navigating Machinery Safety and Compliance Through Effective Product Testing

At Knox Thomas, we specialise in helping clients navigate the complexities of product testing, market legislation and in-service legislation. We provide comprehensive support for CE marking, UKCA marking, and PUWER compliance, often assessing machinery for compliance and providing detailed non-compliance reports. This article focuses on the role of product testing in ensuring machinery safety and compliance, particularly concerning the Machinery Directive and associated standards.

Understanding the Role of Testing in Machinery Compliance

The Machinery Directive mandates various safety and compliance requirements for industrial machinery. However, it stipulates relatively few specific testing requirements. The most common requirement for testing within this framework is detailed in EN 60204-1, section 18, which covers electrical testing. Particular tests to ensure the electrical safety of machinery components include:

  1. Continuity of Protective Bonding Circuit: Verifying the continuity of the protective bonding circuit to ensure it can conduct fault current safely.
  2. Insulation Resistance Tests: Measuring the insulation resistance of electrical equipment to verify that it meets minimum standards for preventing electric shock.
  3. Voltage Tests: Applying a high voltage test to assess the integrity of insulation.
  4. Protection Against Residual Voltage: Ensuring that no dangerous voltages remain after the power supply is turned off.

Light Curtain Safety and Testing

For machinery that uses light curtains as safeguarding measures, specific standards and testing protocols are essential. The relevant standard is EN ISO 13855 (formerly EN 999), which provides guidelines on positioning of safeguards with respect to the approach speeds of parts of the human body. Additionally, EN 61496-1 and EN 61496-2 outline the safety requirements and testing protocols for electro-sensitive protective equipment, including light curtains.

Key Aspects of Light Curtain Testing:

  1. Positioning and Installation: According to EN ISO 13855, the light curtain must be positioned at a safe distance from the hazardous area, considering the machine’s stopping time and the approach speed of a person.
  2. Resolution and Detection Capability: The light curtain must have an adequate resolution to detect the smallest object that could potentially cause harm, typically a finger or hand.
  3. Response Time: The response time of the light curtain, which is the time it takes to stop the machine after the light beam is interrupted, must be tested to ensure it meets the required safety standards.
  4. Environmental Conditions: Testing must account for various environmental conditions, such as ambient light, dust, and vibrations, to ensure reliable operation in all expected conditions.
  5. Functionality Tests: Regular functionality tests ensure that the light curtain consistently detects interruptions and triggers the appropriate safety response.

Noise Level Testing

Noise level testing during product testing at operator workstations ensures that machinery operates within acceptable noise limits, protecting operators from potential hearing damage. The relevant standards for noise measurement include EN ISO 3744 and EN ISO 11201, which describe the methods for determining sound power levels and sound pressure levels, respectively.

Key Aspects of Noise Testing:

  1. Sound Power Level (ISO 3744): This standard specifies methods for determining the sound power level of machinery. It involves measuring the sound pressure levels at various points around the machine in a controlled environment and calculating the overall sound power level.
  2. Sound Pressure Level (ISO 11201): This standard focuses on measuring the sound pressure level at the operator’s workstation. It ensures that the noise level to which the operator is exposed remains within safe limits.
  3. Frequency Analysis: Conducting a frequency analysis to identify specific frequencies that may contribute to hearing damage, allowing for targeted noise reduction measures.
  4. Environmental Factors: Testing must consider various environmental factors such as background noise, room acoustics, and operator position to ensure accurate measurements.
  5. Compliance with Limits: Comparing the measured noise levels with the permissible exposure limits set by occupational safety regulations to ensure compliance.

Testing Requirements for Subcomponents and High-Risk Machinery

Industrial machinery often comprises of various subcomponents that have undergone rigorous testing and bear the necessary compliance certifications, including CE marking. This modular approach means that the machinery as a whole benefits from the compliance of its individual parts, reducing the need for extensive testing of the assembled machine. However, there are specific categories of machinery listed in Annex IV of the Machinery Directive that require third-party Notified Body involvement due to their high-risk nature. Examples include refuse collection vehicles and chainsaws, where the inherent risks necessitate a higher level of scrutiny and certification.

Consumer Goods and High-Volume Electrical Products

For consumer goods and high-volume electrical products, testing requirements are more stringent due to the bespoke nature of these products and the integration of various components. Unlike industrial machinery, these products are not typically made from pre-certified subcomponents. As a result, more comprehensive testing is required to ensure the integrity and safety of the final product. Despite the higher testing demands, much of this testing can still be conducted in-house, provided the manufacturer has the necessary capabilities and expertise.

The Value of External Test Houses

While many testing requirements can be met in-house, there are scenarios where external test houses offer significant value. For instance, IP testing (Ingress Protection) is covered under IEC 60529 and often necessitates specialised facilities and expertise that may not be available within a manufacturer’s capabilities. This testing ensures that the machinery is adequately protected against dust and water ingress, which is critical for maintaining operational integrity in various environments.

EMC Testing Standards

Electromagnetic compatibility (EMC) testing is crucial for ensuring compliance with the EMC Directive and applicable standards. This testing is particularly relevant for custom equipment, products, or machines. Example standards for EMC testing include:

  • EN 61000-6-4: Emission standard for industrial environments.
  • EN 61000-6-2: Immunity standard for industrial environments.
  • EN 55011: Emission standard for industrial, scientific, and medical equipment.

These standards ensure that machinery does not emit excessive electromagnetic interference and is immune to electromagnetic disturbances in its operating environment.

Safety Components and Notified Body Involvement

Safety components represent a distinct category of equipment that requires third-party Notified Body involvement and certification. These components play a critical role in the safe operation of machinery, and their compliance must be verified through rigorous testing and certification processes. Ensuring the reliability and compliance of safety components is essential for maintaining overall machinery safety and meeting regulatory requirements.

The Role of Comprehensive Non-Compliance Reports

At Knox Thomas, we go beyond mere testing by providing thorough non-compliance reports. These reports are instrumental in identifying gaps in machinery safety and legislation compliance. By pinpointing specific areas where machinery falls short of regulatory standards, we empower our clients to take targeted corrective actions. This proactive approach not only enhances safety but also ensures that all machinery meets the stringent requirements set forth by relevant directives and standards.


At Knox Thomas, we understand the complexities and nuances of machinery safety and compliance in product testing. While the Machinery Directive and associated standards may not mandate extensive testing for all machinery, ensuring the safety and compliance of industrial equipment requires a thorough inspection and assessment. By providing detailed non-compliance reports and guiding clients through the certification process, we help manufacturers identify and address gaps in machinery safety and legislation compliance.

For more information on our services and how we can support your machinery safety and compliance needs, contact Knox Thomas today. Let us help you navigate the complexities of market legislation, ensuring the safety and compliance of your machinery through effective product assessment and expert guidance. Our comprehensive approach ensures that your machinery not only meets regulatory requirements but also operates safely and efficiently.

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