Residual risk is alive and ever present in machine safety

Machine safety and product safety are alike when it comes to the issue of residual risk. Engineers are supposed to hold public safety as paramount and prevent bad things from happening. How?

08/03/2010


Machine safety and product safety are alike when it comes to the issue of residual risk. From recent news headlines: Miners killed in an explosion; Workers missing after oil drilling platform burns and sinks; Cars accelerate out of control; Volcano threatens airliners; Storms destroy buildings and kill 10 people. These aren’t supposed to happen.

Engineers are supposed to hold public safety as paramount and prevent bad things from happening. Recognizing hazards and mitigating them can be complex. The dangers involving products and machines change over time; the dangers when a machine is being built are different after it is installed and are different again when it is decommissioned and disposed.

Take for example the recent sudden acceleration problems an automotive company had with their automobiles. Now, we know that the hard cable between the accelerator pedal and the carburetor has been replaced by the black box computer and software.

So – why sudden acceleration? Is it software, hardware, EMI interference, mechanical hinge binding, or some other phenomena introduce by technology innovation? And, what complications have been introduced that impact residual risk? Was this potential hazard identified in the risk assessment and what was the accepted residual risk after mitigation measures?

Who’s heard of a BOP valve? Does BP or Gulf of Mexico help? Yes, that’s a blow out preventer valve used in off shore oil drilling. This particular BOP valve has multiple shutoff valves that are designed to be capable of shutting off the flow of crude oil. The concept of multiple shut off valves is to provide several ways as redundant backup solutions thus mitigating the risk of crude oil ever polluting the Gulf of Mexico. The trillion dollar question is – why did the redundant shut off valves not function properly when the control system called for them to close? What did the risk assessment identify as hazards and how were they mitigated? What was the accepted “residual risk”?

OK, now that I have your attention, everyone should realize by now that residual risk will never equal zero. Since most things in life can somehow be explained mathematically we can now understand why traveling by commercial air is safer per passenger than traveling by automobile. It all boils down to – “per trip”! This would change on a dime if automobiles could hold 200 plus passengers. And, we can also relate this discussion to machine safety. Accepting the notion that residual risk never reached zero, then we also have to acknowledge that hazards will always exist on or around a machine. As management and engineers it is our professional responsibility (and, obligation as defined by OSHA) to identify all hazards (risk assessment) and to reduce those hazards to acceptable levels (mitigation plan). The acceptable levels are those levels you or your Company determines.

In my opinion, just as with the two examples above, there will always be residual risk which only time and continuous improvement efforts combined will push residual risk toward zero but not equal to zero. Welcome to the real world where – Residual Risk Is Alive & Ever Present!

Also read two prior blog postings:

 

· Machine Safety & Residual Risk

· Machine Safety & “Reasonably Foreseeable Misuse”

 

For more on Machine Safety visit: www.jbtitus.com



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
World-class manufacturing: A recipe for success: Finding the right mix for a salad dressing line; 2015 Salary Survey: Manufacturing slump dims enthusiasm
2015 Top Plant: Phoenix Contact, Middletown, Pa.; 2015 Best Practices: Automation, Electrical Safety, Electrical Systems, Pneumatics, Material Handling, Mechanical Systems
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Digital oilfields: Integrated HMI/SCADA systems enable smarter data acquisition; Real-world impact of simulation; Electric actuator technology prospers in production fields
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Getting ready for industrial IoT; Visualizing the (applied) automation continuum; Preventing VFD faults and failures; Using wireless for closed-loop applications
Migrating industrial networks; Tracking HMI advances; Making the right automation changes
Understanding transfer switch operation; Coordinating protective devices; Analyzing NEC 2014 changes; Cooling data centers

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.