This question always results in a difference of opinion. The new Machinery Directive states that the fixings must be retained, (in either the guard or the machine), so this bit is straight forward. What I find leads into debate is the requirement for a "tool" to be used to open them, which is mentioned in various standards that refer to guarding. These standards then go on to state that "the guard should not be easily defeated or bypassed" or words to that effect. I previously spent 20 years in manufacturing industry, in a mass production environment, where it was always stated that the fixings used must not be able to be opened with a commonly available tool such as a screw driver or hex key, as these are tools normally required to adjust equipment and their availability would fall foul of the easily defeated or bypassed requirement. In 2007 I changed jobs and found on my first day that I had inherrited a HSE Improvement Notice that had been issued between my interview and start date. Within the improvement notice was the statement that "current guarding is not properly attached" and "risk assessments were insufficient as not all hazards had been identified". In a meeting with the HSE inspector who issued the notice, they stated that the fixings did not comply as they been able to open them using a steel ruler and tools found on the machinery. I agreed with the inspector as it was in-line the practices I was used to, but the Production Manager questioned the notice as he had not been able to find anywhere in the various standards a list of tools that can or can not be used to open guard fixings. The HSE inspector then pointed us towards BS EN 1088 which contains Note 4, stating :- Typically "defeat in a reasonably foreseeable manner" can be an intentional attempt to defeat an interlocking device either manually or by using a readily available object. Readily available objects can be : - screws, needles, sheet-metal pieces - objects in daily use suck as keys, coins, adhesive tape, string and wire - spare actuators or spare keys for the trapped-key interlocking devices - tools required by the intended use of the machine or readily available tools (e.g. screwdrivers, wrenches, hexagonal keys and pliers) The HSE inspector went on to say that if we carried out thorough RA's as required by the improvement notice, that when it came to assessing the guarding, that if we ask the right questions, we will find ourselves referring to this note as the construction of the guards should be to the same standard as the interlocks fitted to the machine in terms of defeat and bypassing of them. So we did our RA's and replaced the fixings on the machines. I now find myself working for an OEM machinery builder. In meetings with the design engineers, I have stated what I believe to be the correct interpretation of selecting fittings that require a tool and can not be easily be defeated or bypassed. I have pointed them towards BS EN 1088, but because it is a standard that refers to interlocking, they say it does not apply to guarding. I have explained my experience on this subject and point to if the RA asks the question it will come up with the answer of complying with the note in BS EN 1088. The answer I am given to this is that the RA is wrong because it has incorrectly interpreted the standard and if it was the case, our competitors would be doing it. I would be interested to know forum members views on this.

jfw It may be worth looking at; BS EN 953:1997+A1:2009 Safety of machinery. Guards - General requirements for the design and construction of fixed and movable guards 5.4.3 States that demountable parts of guards shall only be removable with the aid of a tool and 3.9 defines a tool as an implement such as a key or wrench designed to operate the fastner.

I have always taken tools to be anything found in proximity to the guard or in the general environment of the work area. Some take this to the limit by using at least some bolts or nuts of a type that require a special key while the remainder are standard - although this has problems of ensuring that these are regularly distributed around the fixing points. Major problems come with rulers, knives and adjustable wrenches as these can defeat many systems. Bob

You appear to have spent your time in a similar environment to me Bob. Anything freely available in the vacinity of the equipment that can open a fixing on a guard means that the guard fails the easily defeatable / bypass test. Therefore it has to be a tool not freely available that can be managed. Just because a tool is required to open a fixing does not mean that the standard has been met, you also have to look at whether the fixing can be easily defeated or bypassed too.

The argument is not about using tamper-proof fixings, its about preventing them being easily defeated or bypassed. A works engineer will need to access this area and will be issued with the correct tool and authorised to access the area. However, an operator must not be able to easily defeat or bypass it so must not have acces to the tool.

It was late when I posted the above reply....Should have added.... Should you choose to use fixtures on fixed guards that are not easily opened (security screws etc), then of course that's great as it provides a belt and braces approach. But we should also remember that as you have stated the guards in question also allow access to other areas also covered by interlocked guards, then in my experience on older interlock fittings (such as the KLM mechanical switches) then fitters sometimes have the key/fitting necessary to bypass the interlock in their toolbox or on their key ring. So I say that its down to your own interpretation and RA to justify what you do, then should it go pear shaped use your RA to defend you chosen route and see if the enforcing body agree or not. They are human as well so of course different inspectors can have differing opinions on what is and isn't acceptable. This of course makes our role as safety professionals even more interesting/challenging.

I do indeed Ron; and as stated have the enforcing authority take a step back from an initially heavy handed approach and see that our interpretation of the law, and therefore our R/A and associated SSOW were acceptable (albeit after some lengthy discussions). But as I also stated different inspectors have different expectations

Graham, I can't agree with your suggestion that the accident could have been avoided by modifying the interlocking "so that safe access could be had". There should have been a separate lockable isolator for the mixing hopper. BS EN 60204-1 states under "Devices for switching off for prevention of unexpected start-up" states that "Devices that do not fulfil the isolation function (for example a contactor switched off by a control circuit) may only be provided where intended to be used for situations that include: – inspections; – adjustments; – work on the electrical equipment where: - there is no hazard arising from electric shock (see Clause 6) and burn; - the switching off means remains effective throughout the work; - the work is of a minor nature (for example replacement of plug-in devices without disturbing existing wiring)".

Graham, Sorry for the delayed reply, I've been away from the office. Perhaps I'm being over-pedantic, but provision of a lockable isolator is not interlocking, unless the isolator cannot be closed with the guard opened, and even then would not be sufficient in this particular case. We seem to agree though that a lockable isolator was the correct solution. I saw a similar plant some time ago and I think the problem with simply using a water jet from outside the guard was that some parts of the mixing paddles weren't exposed to the water jet. The mind boggles at "the guard was closed with the employee inside". What goes through people's minds when they think that's acceptable?