I've been having a 'discussion' with our engineering and fabrication department who are installing a new piece of machinery which has been designed by them. On the top of it is an access door that allows access to the moving parts of the machine (its used to break up small clumps of matter). Access is needed to this area during hygiene and maintenance. They want to use a torque screw to prevent access and I'm saying it should be interlocked too.

My argument is that whilst the torque screw meets legal requirements in preventing access, should the screw not be replaced after maintenance or hygiene then access to the dangerous part is easy and the machine would not stop if someone opened the hatch, thus it fails to danger.

From looking at the rest of machinery and knowledge of the business, I know that its a distinct possibility that at some point this scenario would happen and even with a management inspection before use its not fool proof (tick box exercise) and then all you've got is something to hit the person who signed the form with after the event. You havent prevented the injury.

Thoughts?

Surely the same argument could be used for fixed guards? They should be fixed with a fastening which needs a special tool, however, what if they were not refastened? You could then argue that interlocks should always be fitted?

Yes you could argue that.

My stance is, If there is a need to regularly access the hatch for cleaning etc and there is a general poor safety culture within the organisation that may lead to the guarding not being replaced as seems to be alluded to in the post and there is a risk of serious injury if someone decides to access moving parts then I would try to take human error out of the equation wherever possible.

Para 1.3.8.1 of Schedule 2 Part 1 EHSR section of the SMS(S) Regs says quite clearly that “Interlocking movable guards should be used where frequent access is envisaged”. As usual, in the UK, it doesn’t give a time based definition so we are left with what constitutes “frequent access”.

You don’t say at what frequency access is required and maybe you have not considered that so far? You do not say who will be required to remove the fixed guard; operator or maintenance staff. They present different risk patterns.

So I offer the following as an example of how the frequency issue has been resolved elsewhere. It is just an example and NOT a solution to your case. I know of decisions made that “If the risk assessment determines that workers only require access to the hazard zone infrequently (e.g., weekly or less often) then fixed guards should be a first consideration.” In my scenario the ‘work’ was not undertaken by production staff but by maintenance.

We are all aware of both the well established, acceptable practice of fixed guards and their potential failure modes. Despite those failure modes they remain an acceptable approach in a properly designed piece of kit. It is also acceptable to rely upon ‘competent’ staff to manage the maintenance phase of any machine operations that require removal of fixed guards.
So, in my opinion, to simply insist on interlocking because of potential systems failure is not a positive way to approach this matter. If you conclude from your assessment that access will be frequent then interlocking is required, if not then fixed could be used. ( I hope your guys have done their design assessments etc!)

One final point. As this is an internal design it might be worth checking that if you go for fixed guards that they know that ‘fixing systems must remain attached to the guards or to the machinery when the guards are removed. Where possible, guards must be incapable of remaining in place without their fixings.’ (Para 1.4.2.1 of the above quoted Regs.) The good old days of a few non-captive torx or hex nuts are long gone.

hth
p48

FlashingBlade,

Bearing in mind that you will be required to CE mark this machine, then this should have been sorted out at the design stage.

The best place for me to guide you for now, is EN 953, which has guidance on frequency of access.

A single Torx (I presume you mean not torque) screw must be captive within the guard as has been suggested, you also need to consider the strength of the fixing with regard to the strength of the guard and the forces that it is required to contain.

What does the design risk assessment for the machine say?
What does the assessment against the EHSR of the machinery directive say with regard to this guard?
How often will it need to be accessed?
By whom?
What forces is it needed to contain?

If you have craft engineering staff who are not refitting fixings then this is a culture thing, that is wrong, and must be sorted.

I refuse to call maintenance fitters and craftsmen, Engineers, because they are not.
They are Tradesmen, Craftsmen, possibly Technicians, but, it is doubtful that they are Engineers.
There are very few qualified Engineers who choose to also work on the tools.
Why should they when they can earn more money as Engineers.

Many of the points have already been raised here and suggestions made.

Don't forget IF, you are designing and manufacturing machinery those undertaking this work must not do this unless they have access to ALL of the standards and documents which pertain to the work that they are doing.

So, they must have already ignored the guidance in this standard if this question is being asked?
Else their design is suitable with some confirmation.

Paul you are wrong about engineers - on TV (including BBC) ALL Engineers ALWAYS wear overalls and carry large spanners (or as the BBC arty types would call them "wrenches").

PS spare a thought for "Chemists"!

The issue i suspect is that whilst a single interlocking switch, may be quite a low cost item, there is then the whole safety rated control system to go with it.
What PL is required? Etc.

This question is much more involved than it first seems, if you are requiring an interlocked guard then you are into 62061/13849 territory & there is no way you can lefitimately avoid it.

I would very much consider the various BS listed above. How can you risk assess without knowing the guidance?

If, as the OP states at #1, access is needed a fixed guard is a non starter as it needs to be removed for maintenance so as said, let's not complicate matters. By all means have a permit to work in place but fit an interlock and sleep at night. Just a thought but fail-safe is better than half-arsed control measures.

Determining the appropriate use of interlocks is something that I have had to consider recently, albeit in a different context. As well as the expense, interlocks can have other potentially negative impacts.

Does anyone know of any guidance that can be referred to when deciding if something should be interlocked? I have not been able to find anything in me searches.

Thanks

A few examples of potential negative impacts of using interlocks:

1. It is often difficult to set-up interlocks to cover every possible mode of operation. You either end up with overly complex interlock systems (which can be hard to maintain) or require overrides for some modes.

2. Difficult to perform running checks for diagnosis, commissioning etc.

3. Behavioural impact - people assuming the interlock makes everything safe (it must be safe to do this because the interlock allows it).

4. Job becomes impractical because it takes longer. Deadmans handles/switches are often overridden because the job takes a long time and no one has time (or sees the need) to be present throughout.

5. Lazy design. Adding an interlock is easier than designing out the hazard and hence the opportunity to improve intrinsic safety (and hence overall risk) is missed.

These do not apply to every use of interlock, but what seems to be missing is any useful guidance to say when:

1. Interlocks are not required
2. Interlocks are required
3. Interlocks should not be considered as a suitable risk control.

I have been following this thread from the start with interest.

I do not have any experience with the relevant equipment legislation or directives for machines, however I will give my limited input, with the limited information from the OP:

1. Anti tamper proof Torx fitted to the hatch, to prevent unwarranted access;
2. Interlock fitted to isolate the energy source when removed;
3. Safe Systems of Work devised for the task when the hatch is to be removed;
4. Permit to work system in place ;
5. Trained and competent maintenance staff;
6. Regular inspection of the machine - to include a daily visual inspection;
7. Risk assessment for the task being carried out which would also include the requirements of PUWER.

This above points are made, given that access to the moving parts of the equipment could result in a serious injury.

The poster you have an issue with did say PUWER should be considered.

http://www.legislation.g.../2306/regulation/10/made

In your opinion what would be the result of that consideration?

Regards

I think the important thing is Toe that we have much higher safety standards today than we did many years ago and this has been achieved by having 'many' opinions in the arena and then thinking and discussing them through to a professional and sensible conclusion. It is that which overall delivers the better safety standards.

Regards

quote=westonphil]I think the important thing is Toe that we have much higher safety standards today than we did many years ago and this has been achieved by having 'many' opinions in the arena and then thinking and discussing them through to a professional and sensible conclusion. It is that which overall delivers the better safety standards.

Regards

" PUWER only applies to the equipment once in use by the end user."

Yes it does and so that point is factually correct, but also it applies to equipment provided for use, and that does not mean the equipment has to be in use. In the case of the original poster the Machinery Directive applies to the design and manufacture etc., of the said machine/equipment and that is without question.......to quote yourself "End of".

However, if someone is to consider PUWER and take that to its logical conclusion then they should be considering PUWER before the equipment is put into use and that consideration would, of course if carried out properly, lead to a check that it complies with the community requirements, and thus the machinery directive etc.

In addition to this the original poster made the comment " I've been having a 'discussion' with our engineering and fabrication department who are *installing* a new piece of machinery which has been designed by them."

Therefore Paul, as I understand things the equipment is now in use, unless of course in your wisdom and understanding of PUWER the terminology "“use” in relation to work equipment means any activity involving work equipment and includes starting, stopping, programming, setting, transporting, repairing, modifying, maintaining, servicing and cleaning;" does not really apply to 'installing'.

I look at that statement by the original poster and I can then understand how things can be interpreted differently, and that is really how courts often see things differently. So I would respectfully suggest that PUWER does also apply in this case.

Regards

quote=paul.skyrme]Toe,
Under the Machinery Directive in house use, IS placing on the market, end of.

There is no doubt that use by the person is included in the definition of a 'manufacturer'.

Extract from IND(G) 270 (the easiest ref I have to hand)
The term ‘manufacturer’ is used here to describe the machinery manufacturer
when they:
■ are based in the EU;
■ are based outside the EU but claim their machine fully complies with the Machinery Directive and has been CE marked; or
■ build or assemble machinery for their own use.

Paul is correct in his assertions that the supply regs are where the duties arise in this case. Given that PUWER will also apply it is easy to see how the two can be confuddled. This is especially so given that, for all practical workplace safety control, the outcome would be likely very similar in many simple cases.
But that does not change the fact that failing to recognise the supply regs would leave the employer in the rough and perhaps more importantly, in my opinion, increase the risk of inadequate/inappropriate machinery design.

It's surprising that someone makes statements like that and then further down says "Forget PUWER". It amazes me that they cannot see their own errors.

According to the details provided by the original poster the machine is in the installation stage and therefore the primary legislation which applies it PUWER. By now going through that legislation properly it will take the person(s) back to the machinery directive to check what they have designed and manufactured does actually comply with its requirements. With regards to the statements about "if these debates are going on then it is patntly obvious that the designer and manufacturer that has placed the machinery on the market has failed to meet the requirnts of the Machinery Directive, as incorporated into UK law as the SMSR.". There is no solid evidence to back up that statement and assumptions are being made. This is a discussion forum and we have not seen the equipment in question and so it is clearly not patently obvious and instead it is assumed to be obvious. With regards to what is or is not legal ultimately that would be decided by a court where there is disagreement between relevant stakeholders.
With regards to this statement " PUWER, is relevant to the end user" sorry but this is not complete and 'end user' is not defined in PUWER. PUWER applies as such "The requirements imposed by these Regulations on an employer in respect of work equipment shall apply to such equipment provided *for use or used by an employee of his at work*." If it is being installed then we can reasonably assume one or more employees are installing it and are employed by an employer. Therefore it is reasonable to assume PUWER applies. That does not of course mean other legislation will not have to be looked at as well.

That we may have to go back and fix something it does not in any way change the fact that at the point of installation the primary legislation is PUWER. In addition who is to say the machine actually requires an interlock, sorry but there is NOT enough information to make that decision.
In addition, let's say that after 6 months of running a machine an unforeseen issue is found; it's on site and clearly in use and yet we may then have to go back to the manufacturer and get them to go through their original risk assessment and make corrections. It does not however then mean that PUWER does not also apply.

Ignore legislation, sorry I cannot support that. All relevant legislation should be complied with.

It does not mean PUWER does not also apply. In addition you are not necessarily admitting the failure stated, they are different pieces of legislation and the risk assessment on site may identify something which was unforeseen; this is part of continual improvement and the reasons why risk assessments are carried out. I agree however it could mean there was a failure.

The machine has arrived on site and is being installed and therefore PUWER is the primary legislation. That this now leads the person(s) back to check the machinery directive requirements does not mean it has to somehow being re designed under PUWER. In addition it may well be that the going through the risk assessment again actually determines a fixed guard was actually what was required and therefore the machine is correct and therefore no change to CE marking is required. It may well be a design change is required for both pieces of legislation, it's possible.

If the machine is on site being installed it comes under PUWER and therefore it cannot be disregarded. In addition the statement that if the machine is 'ok as designed then it is ok under PUWER' is incorrect, I am surprised to read it. There can often be unforeseen risks which arise on site and which require people to go back and take a look at the design; also it does not have to be a 'this is illegal' item either and instead it can be an unforeseen hazard/risk which needs to be dealt with. The person risk assessing under PUWER may make a different judgement that did the designer and this may be around the 'reasonably practicable' terminology. Ultimately if something went wrong and it ended up in Court then it would be a judge who would decide.
With regards to the last statement, I really do not see any evidence that people are encouraging companies to break the law; I think they are having a discussion and that would seem to go with the fact that this is a discussion forum. Those discussions can however be snuffed out when 'experts' simply close their minds to other possibilities and interpretations.
I will finish on the point that the HSE often report the cases they win, they do not report on the cases they lose. I do not see the issue with the HSE losing a case though, because often a clarification of a piece of law is required and so it is a positive. So even they can get it wrong until a judge has made a decision, it's life.
PUWER clearly applies based on the information supplied by the original poster; now whether or not the 'guarding' fitted complies or otherwise really requires a more detailed risk assessment and understanding of the facts. It may well be that the fixed guard already fitted is ok, on the other hand it may well be that it is not. The machinery directive must be complied at the design and manufacturing stage, and this is without question, and equally it can apply at other times as well. Proper consideration of PUWER now the machine is being installed will ultimately lead to a proper reconsideration of the machinery directive. If we were clearly in the design and manufacturing stage and NOT in the installation stage, then I would have to conclude that clearly the machinery directive would apply 100%, without question.
Regards

I have to agree teh_boy, Paul does make a lot of sense and I cannot disagree at all with his comments on the relevant EN standards or that the machinery directive applies to manufacturing and design, all those things are spot on.

But equally if the machine is now beyond the design and manufacturing point then other legislation also applies and if properly followed will lead the relevant persons to go back and correct the design, should that actually be required.

So we are not disagreeing about the need to check the machine is safe, and *if/where* necessary then improve its safety, and rather we are just having a good debate/discussion to explore also the wider implications.

I have seen many times 'experts' on TV in complete disagreement with each other, it does not however stop the debate/discussion.

Regards

This Is in my opinion a brilliant debate to start off the new year.

I though I Would throw this in, the definition from Wikipedia

An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics, and ingenuity to develop solutions for technical, societal and commercial problems. Engineers design materials, structures, and systems while considering the limitations imposed by practicality, regulation, safety, and cost.[1][2] The word engineer is derived from the Latin roots ingeniare ("to contrive, devise") and ingenium ("cleverness").[3][4]

The work of engineers forms the link between scientific discoveries and their subsequent applications to human needs and quality of life.[1]