Machine Safety: hazard remediation, mechanical versus control system solutions

What's the residual risk for Cat 3 hazard mitigated by a fixed steel plate? Did the repair result in a control reliable solution? Are physical barriers or control solutions better to reduce risk. Five steps define the hierarchy of measures for hazard mitigation and machine safety risk reduction.

10/11/2012


So, for a Cat 3 hazard mitigated by a fixed steel plate, what’s the residual risk? Cat 1? Would that be a control reliable solution? How come we can’t simplify the process for all? In my opinion, all of the machine safety and risk assessment standards approach the risk assessment and risk reduction process as somewhat complex. I’m talking about the entire process for a machine. Including the risk reduction measures to achieve acceptable residual risk for every hazard, mechanical or control system related.

 

The five steps of the “Hierarchy of Measures” for hazard mitigation begins with design it out:

1.) Eliminate the hazard – design it out

2.) Isolate the hazard with hard guarding

3.) Add additional engineering, guards, devices, or layers of safety

4.) Administrative controls like – training, signage, assessments, etc.

5.) Personal protective equipment (PPE) like - goggles, gloves, outer clothing, shields, etc. 

Arguably, steps 1, 2 and 3 can be focused at the mechanical design of the machine including the application of fixed guards. By now most risk assessment practitioners understand this and that they need to transition to the control system for additional hazard mitigation as needed to reach acceptable risk. Steps 4 and 5 are also considered as acceptable solutions for risk reduction.

 

However, don’t risk Categories (B, 1, 2, 3 & 4) only apply to the “control system”?  When you check out the Category descriptions you see words like; control reliable, single channel with monitoring, dual channel with monitoring, and more. Does this mean that machine safety hazards, other than those addressable via the control system, are only dangerous or not dangerous? 

 

When a fixed guard is applied over a hazard the standards say that tamper proof attachment devices should be used to prevent unauthorized persons from removing the guard. Okay, so I guess it’s dangerous or not! On the other hand, by applying a warning sign is the hazard dangerous or not? How do you rate or measure the risk reduction of a warning sign? In one standard hazard levels are described as; high, medium, low and negligible. Will that work for all hazards including the control system? Or, do you still need Categories for the control system? If you still need Categories for the control system how do you transition into and out of Categories during the risk reduction flow process? 

 

Perhaps the machine safety standards could take a look at covering all of the mechanical, electrical, control systems, and administrative solutions within their section titled something like “Risk Reduction Measures.” Then, there could be obvious transitions during the journey of the risk reduction flow process. I’ve seen many an end user having difficulty with this issue versus an original equipment manufacturer (OEM). But, the OEM isn’t necessarily concerned with this issue because he’s not the target of OSHA and the end user is most always concerned with Steps 4 and 5 of the Hierarchy of Measures.  

 

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, hazard remediation, mechanical versus control system solutions.

 

J.B. Titus, CFSERelated articles:

Machine Safety – does a risk assessment need to be updated for a minor modification to a machine?

Machine Guarding & The Hierarchy of Measures for Hazard Mitigation

Machine Safety – does OSHA reference consensus standards for compliance?

Machine Safety: Is OSHA okay with my 'acceptable' risk mitigation?

  

Contact: www.jbtitus.com for “Solutions for Machine Safety”.



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...
2016 Engineering Leaders Under 40; Future vision: Where is manufacturing headed?; Electrical distribution, redefined
Strategic outsourcing delivers efficiency; Sleeve bearing clearance; Causes of water hammer; Improve air quality; Maintenance safety; GAMS preview
World-class maintenance: The three keys to success - Deploy people, process and technology; 2016 Lubrication Guide; Why hydraulic systems get hot
Flexible offshore fire protection; Big Data's impact on operations; Bridging the skills gap; Identifying security risks
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
Getting to the bottom of subsea repairs: Older pipelines need more attention, and operators need a repair strategy; OTC preview; Offshore production difficult - and crucial
Applying network redundancy; Overcoming loop tuning challenges; PID control and networks
Driving motor efficiency; Preventing arc flash in mission critical facilities; Integrating alternative power and existing electrical systems
Package boilers; Natural gas infrared heating; Thermal treasure; Standby generation; Natural gas supports green efforts

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

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.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me