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Machine Safety: Only engineers can lead the Risk Assessment process?
September 12, 2012
Over the past 10 years significant focus has been spotlighted on machine safety. Simultaneously, an incremental documented process called “Risk Assessment” has been introduced to industry. In fact, many updated standards require that risk assessments be performed. And, a new standard, ANSI B11.0 – 2010, Safety of Machinery – General Requirements and Risk Assessment, is dedicated to this topic. With all this attention folks still are not clear regarding whether an engineer is essential to lead the risk assessment process.
ANSI B11.0 provides the following two definitions:
“3.69 risk assessment: The process by which the intended use of the machine, the tasks and hazards, and the level of risk are determined.”
“3.70 risk assessment process: The entire process of identifying hazards, assessing risk, reducing risk, and documenting the results.
Industry experts recommend that a team concept be utilized for conducting risk assessments. The team leader should have prior experience and be very familiar with the risk assessment process. Any mix of the following skills and expertise within the team are also recommended:
• Environment, health and safety
• Maintenance and/or field service
• OEM, system integrator, or supplier(s) with backgrounds in safety/engineering.
The risk assessment process should be carried out by this team for each machine to identify all hazards in order to implement risk reduction(s) using the five mitigation steps as follows:
1) Eliminate the hazard – design it out
2) Isolate the hazard with hard guarding
3) Add additional engineering, guards, devices, or layers of safety (controls or systems)
4) Administrative controls like – training, signage, assessments, etc.
5) Personal protective equipment (PPE) like - goggles, gloves, outer clothing, shields, etc.
Steps 4 and 5 probably don’t need any engineering expertise and most often the maintenance cadre can apply hard guards in Step 2. Engineering skill sets are likely to be helpful for Steps 1 and 3 as part of the team. The reason for this position is - as hazard levels are determined and mitigation steps are evaluated, it’s helpful for someone to potentially evaluate the application issues when the mitigation option involves the control system. It could also be possible that an engineer could evaluate a mechanical modification to the machine hazard as a mitigation option. However, timing wise, these two evaluation steps could also occur following the risk assessment report.
In another case example it might be helpful to have an engineer on the team in order to help determine an existing guarding level for a given hazard. Establishing existing Category levels for each hazard is one of the first steps in the risk assessment process. It is from that hazard level that mitigation options are considered in order to reach an “acceptable” (reduced) hazard level for each identified hazard. For example, it may not be obvious to a team if the current design includes control reliable wiring, safety rated components, and other functional safety provisions. Yet, in most cases an engineering skill set is not required to help answer (for each hazard) the three questions; how serious, frequency of exposure, and possibility of avoidance?
In practice, we do frequently find an engineer leading the risk assessment process because someone has made that decision. However, in my opinion and according to current industry standards, it is not required that an engineer lead the risk assessment process. Having access to an engineering skill set can be helpful to the process.
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Contact: www.jbtitus.com for “Solutions for Machine Safety”.
For more than 30 years, J.B. Titus has advised a wide range of clients on machine functional safety solutions, including Johnson + Johnson, Siemens, General Motors, Disney, Rockwell Automation, Bridgestone Firestone, and Samsung Heavy Industries. He holds a Bachelor of Business Administration degree from Oklahoma University in industrial management and an MBA from Case Western Reserve University in marketing and finance. He is a professional member of the American Society of Safety Engineers and is OSHA-certified in machine guarding. Titus is also TUV-certified as a Functional Safety Expert and serves on several American National Standards Institute, National Fire Protection Association, and National Electrical Manufacturers Association national safety and health standards committees. Reach him at jb(at)jbtitus.com and via www.jbtitus.com.
Thursday, 13-09-12 10:50
The title of this article is unfortunate. Many very good engineers do not have the operations or maintenance field experience to fully comprehend the human factors involved in risk. If they did, then every machine design would be as intrinsically safe as possible at the start. Safe operation and maintenance would be the path of least resistance. My experience is that operational necessity will ALWAYS override the most critical and complex security and safety systems. Anything that takes away from production time is invariably bypassed at the worst possible moment.