Safety standards for/in machinery controls

[HCBFlash]

A follow-up on thread242-141768.

I did in fact leave the facility and company I worked at, where unsafe machine controls were a concern of mine, and just in time.

A man fell into one of these machines on a night shift a few months ago (about 6 mo after I left). He was killed, and most of his body destroyed entirely. State health and safety inspectors were given a list of hazards by myself prior to the accident, but none were able to be investigated and confirmed still a month or 2 before the death.

A simple cable style Emergency stop switch and contactor would have made this "simply" a badly injured/lacerated bodily extremity.

From what I've heard, it was determined that:
1- the individual was not pushed into the machine by another person.
2- the victim was not operating the machine in the manner he'd (supposedly) been instructed.
3- the physical guarding of the blades should be made more difficult to remove or defeat.

I can't recall ever praying for lawyers to swarm before hearing of this.

Still, this is not a forum for outcry. I cannot find anything in OSHA standards 1910 Subpart O requiring emergency machine shut-down actuation devices.

What am I missing here?

 

[JLSeagull]

Study the NEC (NFPA 70) looking for machinery. I think that you will find that controls or disconnecting means are required within sight of the machinery.

 

[dbaird]

go to:

http://www.jicosh.gr.jp/english/guideline/Machinery/SafetyStandards.html

for an understanding of risk assessment.... then consider this:

Control Reliability and Component Failures
The sections identified below for control reliability and component failures are very similar to the intent of Category
and 4 as defined in European Harmonized Standard EN954-1. Single component failures are referred to as a
determining factor in the safety of machinery. In all cases- if a single component fails, it shall not prevent the normal
stopping action of the machine, and it does prevent the machine from re-starting.
It stands to reason that if a single component fails, there must be a similar component available to complete the
stopping action, and that there must be some type of checking circuit to acknowledge that single component failure
occurred to prevent a re-start of the machine. This would suggest some type of redundancy of the various
components and self checking circuitry to identify any failures would be required if a circuit is to be control reliable.
OSHA 1910.217 (b) (13) Control Reliability
The control system shall be constructed so that a failure within the system does not prevent the normal stopping
action from being applied to the press when required, but does prevent initiation of a successive stroke until the
failure is corrected. The failure shall be detectable by a simple test, or indicated by the control system. This
requirement does not apply to those elements of the control system which have no effect on the protection against
point of operation injuries.
ANSI B11.19: 6.1 Performance of the Safety Related Function(s)
When a component, module, device or system failure occurs, such that it or a subsequent failure of another
component, module, device or system would lead to the inability of the safety-related function(s) to respond to a
normal stop command or an immediate stop command, the safety-related function shall:
• Prevent initiation of hazardous machine motion (or situation) until the failure is corrected or until the control
system is manually reset, or:
• Initiate an immediate stop command and prevent re-initiation of hazardous machine motion (or situation) until the
failure is corrected or until the control system is manually reset; or
• Prevent re-initiation of hazardous machine motion (or situation) at the next normal stop command until the failure
is corrected or until the control system is manually reset.
In the Explanatory Information are the following comments:
• The intention of a manual reset is to encourage the diagnosis of the failed component, subassembly, device or
module.
• Control Reliability:
— Is one of the strategies that may be used to meet these requirements;
— Cannot prevent a repeat cycle in the event of a major mechanical failure or in the presence of multiple
simultaneous component failures;
— Is not provided by simple redundancy. There must be monitoring to assure that redundancy is maintained.
ANSI B11.20: 6.13 Control Component Failure Protection (Control Reliability)
The control system shall be designed, constructed, and installed such that a single control component failure within
the system does not prevent stopping action from taking place but will prevent successive system cycles until the
failure has been corrected.
This requirement only applies to those components whose failure can result in a hazardous condition.
In the Explanatory Information it states: Protection against the consequences of failure of control components should
not depend solely upon simple redundancy. Additionally: Control component failure protection does not mean “fail
safe”. “fail-safe” is a magnitude of reliability that is not practically achievable.
ANSI/RIA R15.06: 4.5.4 Control Reliable provides a similar definition of control reliability as above.

David Baird

Sr Controls Designer
EET degree.
Journeyman Electrician.

 

[HCBFlash]

Thanks for that link dbaird, excellent.

That said I'm still looking for legally binding requirement of safety devices for the immediate shut down of a machine that is always within reach of the operator. Redundancy and fail safe are obviously the best practices, and apparently required where such shut downs exist.

I believe I've come across regulations requiring mandatory safty controls on punch presses, but no scope extending to any or all other industrial machinery which pose serious bodily danger to operators.

Lockout/tagout is extensively regulated and required for repair and maintenance functions, yet I find no legally binding requirement of similar extent for normal operations.

I do not have a copy of NFPA70E, and I plan to get one and possibly attend a course about it. If you or anyone else has a copy of 70E and are somewhat familiar with it, perhaps you can post a refence to such a requirement(s) within it. Of course that still leaves the issue of an AHJ adopting 70E as a binding safety standard within a given jurisdiction.

Heck, I didn't even know the guy that got killed, and don't recall ever working on the particular machine, but I still feel some sort of inward personal responsibility for not being able to put more substantial pressure on the plant's managment to find and adress such hazards to prevent such incidents. It seems that 1910.o won't help, but I'm not finding any section that does.

I remain in the field of working on controls for dangerous machinery, and want to do my part to communicate such hazards and requirements to management where they exist. I certainly don't do this to generate work!!!! I myself and others I work with are at risk here.

Safety meetings are required and suggestions sought at nearly every worksite I've been at over the last 15 years or so, but many suggestions are only ever given a little lipservice, and subject to a lot of excuses, procrastination and energy to sidestep such issues. Frequently pushing this sort of thing is "career suicide", but I'm more interested in myself and coworkers going home every night, and uninjured. There are more than a few "safety guys" that share my frustration, but are afraid of pushing things without rock solid footing.

Perhaps I need to have this discussion with the governmental inspectors,,,, again (and again and again.....) but it's been fruitless in the past, as mentioned in my original posting.

 

[dpc]

No one has adopted NFPA 70E as a legal requirement that I'm aware of.

I think OSHA already addresses this issue, but I don't really have time to search for it. You could just call OSHA's regional office in your area and ask them. That's what we're paying them for, I would think.

Let us know what you find out.

 

[dbaird]

link to OSHA comments on NFPA 70E:

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=24617

David Baird

Sr Controls Designer
EET degree.
Journeyman Electrician.

 

[HCBFlash]

dbaird;

Returning to your post of 05FEB;

I've had to take some time to work through that, and was hoping to see some others response as well.

"OSHA 1910.217 (b) (13) Control Reliability" pertains specifically to powered punch presses where an operator manually feeds material into the press.

I've been around a few of these things, and a long time ago (in a place far from where I am today) I was asked to build and install controls to satisfy those specific requirements on 2 fairly small presses. It didn't take me long to determine that equipment ("controls") was readily available for that precise purpose, and I couldn't build a control system to do that task anywhere near as well, or quickly, or inexpensively as I could purchase it.

It appears to me that someone did for punch presses what I'd like to see done for ALL machinery posing such a level of hazard to operating personnel.

ANSI B11.19: 6.1 is a standard I respect and completely agree with and support, but it is not a binding standard for most machinery, and for no machinery directly

Where I am in such a position to affect such equipment safety, I do just that. Rarely however am I in a place to specify or construct such safe machinery control systems without having to establish their need or desirability to those who own or manage and supervise the use of such equipment.

In the time since your reply above, a man was killed in an industrial accident where I am also employed. The fatality and associated equipment was not electrical, nor fitted with electrical controls. The man was however literally within reach of a different piece of equipment that could as easily have killed him, had he needed to stop it by relying on a poorly implemented "E-stop". You better believe I'm upset, and feeling even greater motivation to affect some changes.

If you don't see any postings by HCBFlash for a while, I want it to be because he's gone fishing. If I don't see dbaird, jraef, dpc, JLSeagull or the other regulars posting I don't even want the idea of an industrial accident to cross my mind.

BE SAFE!