safety circuits

[richerdick]

i am working in a printing press the uk and have been requested to make some modifications to a guarding circuit on the printing press. I have some conecrns with how i stand
legally i am sure that some of you will have come across this problem before.
the machine has evolved over many years and although the most upto date parts are ok the older part of the machine (which is the part i need to modify) in a safety sense is outdated. i calculated that designing the machine from new there would undoubtably be catagory 4 safety circuits used. but the existing safety guarding only meets catagory 1. i want to add some guard switches to an existing guard circuit, how do i stand legally according to the hse regs. i will undoubltably be making the machine safer, but the limits i select will not be adequate to the current standard although they will be better than all the other guarding on the machine. It would prove too costly to update the whole circuit and somewhat pointless as much of the rest of the machine is the same. any thoughts??

 

[ozmosis]

Why has someone requested you to do it?-to make it safe not safer.
If the task does not take into consideration evaluating the cost and doing something about it, then all are liable.

This is a quote from the Machinery Directive 98/37/EC:
“Machinery must be constructed that it is fitted for its function, and can be adjusted and operated without putting persons at risk when these operations are carried out under the conditions forseen by the manufacturer.”
“The measures must exclude any risk of accident...”

As you have already stated that the measures you would undertake are not within the current standards then I would say leave it alone unless someone is prepared to fork out the cost to get it right. Having said that, you cannot now leave it alone. If you know something is not right and maybe not safe, then you have to do something about it.

 

[richerdick]

At the time of installation the machine would have met the required safety standard.
what i am trying to say is that as current standards have developed they required more advanced safety features for example in this situation the existing guard safety circuit utilises just limit switches connected in series to a plc input that will then stop the machine. guards have some
current safety requirements might also require that the guards have some sort of hard wire circuit and even error checking capabilities. is it the case that in say adding one guard to the old type guard circuit in a similar fashion that i would be leaving myself exposed. does the hse expect that old equpment is bought up to new standards or do the regulations only apply to completely new designs

 

[itsmoked]

Can't even afford capital letters and punctuation how could they afford better safety?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[richerdick]

Comma after punctuation please.

 

[waross]

"It's too early in the morning for these negative waves."
Oddball, Kelly's heros.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

I think what really needs to happen here is what is called a "Safety Audit", something typically performed by a qualified approval agency. TUV I know does them worldwide and when they are done, they will have identified the safety level needed, all of the safety issues they find, then an outline as a path to progression for meeting that safety level. You then, as the machine engineer, are responsible for executing that progression path by using appropriate means at your disposal, but you do not take on the burden of responsibility for identifying the risk. Here in the US there are other Consulting Engineering firms who specialize in that work as well. They don't specify products, they just do the risk assessment.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[ozmosis]

As I understand it:
1) If you do nothing and someone has an accident, then you are liable, even if you knew nothing about it.
2) If you do nothing and nobody has an accident then nobody will know apart from your conscience.
3) If you do something but it is the wrong something, then you are liable as there are standards to advise on this and doing something implies you are knowledgeable about a problem.
4) Taking advice from the HSE prior to doing anything is a good approach, as long as you do it. You are never covered 100% against liability in an accident but doing 4) means you have covered the "due diligence" aspect.
5)Contact a company like Siemens, especially if you are in the UK and working on a printing machine. Chances are the PLC you talk of is one of theirs anyway and they will get their 'Safety Integrated' folk in to provide a decent solution (probably with one of their solution partners).

http://www.automation.siemens.co.uk/main/business groups/safety/

Alternatively, your PLC company often has a 'safety' division-ask them.
As I recall, HSE are there to advise. I would contact them to ask if they can advise the correct level of safety required.