An ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis, operating efficiencies and cost savings, as well as all relevant safety standards, such as those from NFPA, ANSI, RIA, IEC, ISO and OSHA. About J.B. Titus.
Machine Safety: How safe is safe enough?
January 12, 2012
In machine guarding, how safe is safe enough? Over my 40 years in industry I’ve heard this comment many times. Is this attitude driven by “safety culture” or is it just a product of qualitative risk management? Is this why risk management for machine guarding and functional safety is advancing globally to quantitatively derived engineering and validation?
No, this blog is not about the new EN ISO 13849-1 and Performance Levels, etc.
This blog is about other efforts being evaluated, created, and launched with the objective of “creating a more actionable outcome and enhance the ability to achieve a more predictable, sustainable and safe work environment. It also can help risk assessment teams realize that the result of a risk assessment is not necessarily a conclusion that the condition is safe, but rather an acceptance that the condition is safe enough.” This is the conclusion of an article in this month’s Professional Safety magazine written by John M. Piampiano and Steven M. Rizzo. My assessment of their article is that it enhances the existing qualitative risk management techniques illustrated by existing standards like ANSI B11.TR3 and ANSI/ASSE Z690.3 by combining severity and probability estimations for the severity of injury, more through definitions of each injury level, and a new Risk Matrix that looks eerily similar to a risk matrix in the new EN ISO 13849-1.
The writers take these concepts a step further in their model by introducing Administrative Controls versus Engineering Controls based on the different levels potential injury. They also help the SH&E professional understand that levels of residual risk will always result at this point and that individual company risk tolerance is the responsibility of company management. In my opinion, this clearly places the decisions for various levels of risk mitigation in the hands of company management. Ironically this approach seems to follow ANSI B11 – 2008, General Safety Requirements Common to ANSI B11 Machines. This standard clearly identifies that final risk level mitigation rests with company management because they make the decisions for risk tolerance, aka residual risk.
Is this model “safe enough” and how does the result compare to the quantitative requirements of EN ISO 13849-1? Only you can answer this question.
Your comments or suggestion are always welcome so please let us know your thoughts. Submit your ideas, experiences, and challenges on this subject in the comments section below. Click on the following text if you don't see a comments box, then scroll down: Machine Safety: How safe is safe enough?
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.