Safety Lifecycle: Stage 5 Maintain & Improve

The Functional Safety Lifecycle and YOU!

Stage 5: Maintaining and Improving Your Safety System

By Tyler Knutson, Automation Specialist, Safety


Machine safety has become more recognized than ever before. Employers and equipment manufacturers are tasked with providing equipment that is free from recognized hazards yet remain efficient, productive, & competitively priced. Revere Electric Supply, in partnership with Rockwell Automation, provides the tools needed to improve compliance, simplify development, reduce design time, and reduce costs.


In Stages 1 -4: You learned the importance of having a proven method of providing documentation showing a machine is safe to operate, mitigation techniques required, developing the functional safety requirements for your newly assessed machine, using the tools needed to properly design & verify your safety system, and ensuring your safety system was installed properly and to your specifications.



For Stage 5, we will focus on ensuring that your system is periodically tested for compliance and re-evaluated if changes are made to your machine.

How do I Maintain my Safety System?

  1. Periodic testing* should be done to verify proper system functionality
  2. Machine modifications that affect safety require validation of the safety function may require additional assessments:
    • Program changes
    • Safety system use
    • Hardware or software changes
    • Machinery changes
    • System modifications
    • Speed changes


*Periodic Testing Requirements: The standards say that periodic testing should be done to verify proper system functionality. (There is no defined period or timeline that is suggested)


"Should the safety-related software be subsequently modified, it shall be revalidated on an appropriate scale." (ISO 13849-2, 9.5)



Providing safety for your facility doesn’t just stop at the hardware installation and verification. It′s important to make sure that your facility is kept up to code and your employees are following the guidelines laid out in the designated process. Changing the system without following the safety lifecycle could result in additional damages to your organization, should someone get hurt.


In the end, your organization should have a copy of the following pieces of documentation:

- The relevant standards which you’ve designed to (per Stage 1: Risk Assessment)

- The functional Safety Requirements & Functional Safety Description of the SRP/CS (per Stage 2)

- Fault Exclusions & Assumptions

- Bill of Material (Stage 3)

- Typical Wiring Diagram (Stage 3)

- SISTEMA Performance Verification (Stage 3)

- The Verification and Validation Plan (Stage 4)

For more information into providing the appropriate products to meet your risk assessment and functional safety specifications, please review the following:


Rockwell Automation Machinery Safebook 5

Rockwell Automation Pre-Engineered Safety Functions




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