Morning Rick,

I've not worked with large plant much but I would agree with you in that the system should be locked out.
What negatives come from locking the machine out? I can think of a few negatives that could come from not locking it out and that not being sufficient...

And the production supervisor walks past, sees a stopped machine closes the interlock releases the E-Stop presses start - it has happened with fatal consequence

Also are the interlock and E-stop actually two separate systems? I have seen set-ups over the years where they have been wired in to the same circuit especially where one or both devices have been retro-fitted to the machine.

Lock it out!

It's no good having two separate protections each of which can easily fail.

Lock it out.  Only way to ensure the machine is not started up inadvertently is by isolating it.  Interlocks and emergency stops are not robust means of isolation and are not designed to be used as such.  Having worked with machinery in the past, I would not go into the guts of a machine unless I knew it was isolated. As I'm not familiar with your particular machine, the other thing to bear in mind is whether locking it out will prevent all parts of the machine moving as some presses utilise gravity or stored energy as a motive force for operation.  Lock it out.

Hope this is useful.

As above.  Lock out.

Definitely lock out however I would add to ensure that the correct circuit has been locked out.  I remember reading about a case where a worker isolated one of three augers and correctly locked it out.  However during maintenance it started and caused serious injury.  Apparently the isolators were wrongly marked or wrongly wired and it had never been noticed before.  Also as has been said before ensure any stored energy is dissipated. 

What type of press though.

I used to work for a company that did machinery control systems, one of the biggest global OEM's of the stuff.

One of our service guys was on site, working on a press.

We had just been taken over by another global corporate and they had forced corporate computing policy onto us.

Mandatory screen savers after x minutes, with a password to de-activate.

Nick was running the whole press in test mode from his laptop.

There was no-one at risk.

An issue happened and he needed to click a button on the screen with the mouse to instigate a controlled stop.

He couldn't do this so he had to hit the e-stop, that caused a loss of several £100k's of cost to the printing company, the web tore, and the whole press had to be re-webbed which took 4 hours, so too late to print the morning papers, they had to be transferred to another press works and there was riots.

So, don't take it that ALL presses are simple machines that can be easily LOTO's/

A small say perhaps 10 or 20 tonne blanking press which has a single die for forming steel, with a single point of isloation, then fine.

A large 6 or 8 tower say newspaper printing press such as doing things like the Daily Mail, the Times, etc. this has multiple points of isolation and for it to be effectively maintained safely and economically requires zoning and functional safety.

Not every engineering problem is as clear cut as LOTO.

Simple machines, yes, complex machines one must rely on the functional safety that has been designed in, and obviously verified as working and correctly maintained there after to comply with statute law.

Don't forget all sources of energy though...

As with many aspects of Health and Safety, competency of the person assessing comes into play!to determine what is needed! Ive worked with Directors that believe once it has a CE mark we are good to go! Engineers that order without thinking ( well CE mark is saying all ok!!!) Dont want to spend on getting a PUWER assessment done then machines stand idle! Get a PUWER done and not fit for purpose now machine stands idle waiting to have alterations done!! I have also worked with over zealous Health and Safety Managers who want to Lock Off everything in sight and nearly caused total meltdown of the factory due to their lack of understanding!

So if its complex and you know your way around ISO 13849 and IEC 62061 (good luck) can establish categories and performance level then thats great however i prefer to work in a team with the electrican and engineer to do the assessment.

Dont forget however PUWER must account for misuse of machinery

Originally Posted by: mistyhall

As with many aspects of Health and Safety, competency of the person assessing comes into play!to determine what is needed! Ive worked with Directors that believe once it has a CE mark we are good to go! Engineers that order without thinking ( well CE mark is saying all ok!!!) Dont want to spend on getting a PUWER assessment done then machines stand idle! Get a PUWER done and not fit for purpose now machine stands idle waiting to have alterations done!! I have also worked with over zealous Health and Safety Managers who want to Lock Off everything in sight and nearly caused total meltdown of the factory due to their lack of understanding!

So if its complex and you know your way around ISO 13849 and IEC 62061 (good luck) can establish categories and performance level then thats great however i prefer to work in a team with the electrican and engineer to do the assessment.

Dont forget however PUWER must account for misuse of machinery

I do, it is  a big part of my business, and growing, that along with PUWER & CE assessments.

I don't know many electricians that even understand 60204 let alone 13849 unfortunately though.

I can't get to the OP now on this screen, but IIRC there is the mention of a web, now re-webbing a multi tower printing press is not a 5 minute job.

I think that this is another scenario where the rest of the posters can only comment based on their experience, and it is only the OP that has the full picture.

There are issues with the "MD" and the acceptance of machinery such as requiring the end user to confirm CE compliance, which if you read the wording is really required, but, most end users don't have that capability, and even if they did anc could prove that the machine was non-compliant the answer from the OEM would be something like, "well your wrong, we've sold hundreds of these and no one else has aver said that that is wrong, so you must be wrong".

Heard it before, and will probably hear it again, even when you quote the law and the standards, they just stonewall you and demand money to change things to be compliant with legislation.

The end user is then the one at risk from prosecution for using unsafe machinery, the OEM gets away with it.

I would ask the operator why they wouldn’t want to use a lock off system? Why so adverse to getting a padlock and attaching it to an isolator? It will probably be time - have to walk to get one, sign one out etc or and hopefully this does not happen, but it could be a case they can open an guard, circumvent the isolator and leave the machine running to clear a jam where by using a padlock on the power isolator would prevent this.

Ask the question and get them to tell you why they couldn’t simply lock off the isolator.