OT More guard questions...........

So we had a debate in the shop of proper wiring of guards today. New school says soon as you add and new e-stop or guard switch the safety circuit needs to come up to today’s standard (dual redundancy, safety relays ect ect). Old school says only time it needs to meet new standards is if it’s a new machine. The circuit which switch is being wired to has the e-stops and guard switches wired in series to a relay. I can see both points but I am having a hard time finding information what is the proper way. Any help would be greatly appreciated.

I know in the UK, if you move a machine then you must upgrade the safety circuits to the current standards. Not sure about adding a guard or whatever to an existing machine.

My understanding in Oz, if you modify the machine in any way then it has to be brought up to current standards

Early this year I was at a Rockwell Automation safety seminar. It was explained to us that if you work on the safety circuit you need to update. Let's say the machine has old style E-stop buttons and one has a bad contact. You are required to replace it with a new style manual reset one. It is still unclear how far you need to go into the rest of the machine for a simple repair.

I know here in Ontario as soon as you make a modification that requires any type of interlocked guarding, it triggers a Pre-Start H&S review, which does cover safety circuits, so they need to meet the current standard.

I would think, as an example, adding 1 or 2 e-stop buttons would not trigger any type of upgrade.

Personally I think all machines should be reviewed on a regular basis to insure they continue to meet current safety standards. Not just when modified. The safety standards are in place to protect people.
Just because the machine was from the time before guards and any e/stops and has never been modified does not make it ok to use. The owner of a machine is responsible for it's safe operation, and it is your responsibility to inform them when it no longer meets the standards.
If they are unwilling to spend the money on safety issues, then it is probably not the safest place to be working.

In the UK we have the "Machinery Safety Regulations" which apply to new equipment and are the regulations which require suppliers to CE mark their products. These regulations also apply to old equipment if it is altered/refurbished in any way. There is, however, another set of regulations called the "Provision and use of work equipment regulations" (normally referred to as "PUWER") which contains almost identical requirements to the machinery safety reg's but applies to ALL equipment used in a place of work regardless of age or condition. It is not, therefore, OK to use equipment which does not meet the current regulations even if that equipment was manufactured before the current machinery safety reg's came into force.Andybr

OK say you do upgrade as your modifying the safety circuit this machine if I understand correctly would need a new CSA aproval am I correct on that understanding??

Oh there are "Real" requirements.
Check out this OSHA site.
I don't think that you'll get a definitive answer from PLCS.net though.

Good luck
gbradley

Thanks for the info. I have been a long time reader first time posting though. Thanks again

mordred said:

OK say you do upgrade as your modifying the safety circuit this machine if I understand correctly would need a new CSA aproval am I correct on that understanding??

Click to expand...

Depends where you are in canada I think. We don't need approval by CSA here in Ontario, the system as a whole must be signed off and stamped by a P.Eng. The system is help to the current CSA standard that is applicable as per the Ministry of Labour. (ie. CSA Z432)

If you want to know the basics, look at section 7 of the Occupational Health and Safety Act regulations. There is a good table that shows when/where a review and sign-off is required.