Palletisers: Particular attention needed

The Health and Safety Executive (HSE) has recognised palletisers as a class of machine that require particular attention and outlines safety principles for them. This includes guarding of machine entry or exit points, with methods such as interlocking moveable guards, captive key exchange systems or electro-sensitive protection equipment (ESPE), such as light curtains. 

Due to the size of palletisers, if they are not appropriately guarded, full body access within a machine is a common occurrence. This means that personnel can be in the machinery without the knowledge of those outside and it might be re-started with severe consequences. It is therefore essential that guards are of the correct dimensions to stop people getting under or over them. 

The height of distance guards must therefore be selected using Table 2 of EN ISO 13857 ‘Safety of machinery - Safety distances to prevent hazard zones being reached by upper and lower limbs’, rather than Table 1. Where light curtains are in place, it should be safe to assume that operators are fully protected, but we all too regularly see them positioned incorrectly therefore affording no safety benefit. 

One option to improve safety at entry/exit points is to use a Captive Key Exchange system, where a mechanical key must be removed to isolate the machine and release another key, which the person takes with them into the palletiser. While the key is with the person the machinery cannot be re-started until they return it.

Which standard to follow?

The safety standard that should be followed to ensure safety is ‘EN 415-4: Palletisers and Depalletisers’. Originally published in 1997 by CEN, the European Committee for Standardisation, a decision was taken in 2006 to completely revise the Standard, taking into account changes in machinery technology such as the increasingly widespread use of industrial robots. The reasons given for the review also specifically mentioned ‘the additional risks posed by palletising and depalletising systems’, as well as ‘additional measures to minimise the risk of a machine being reset and restarted while someone is inside the machine’.

CEN’s aim was to publish the revised version of EN 415-4 by 2011, but it is still under development. This means that while EN 415-4 had been harmonised to the old Machinery Directive 98/37/EC, when this was replaced by 2006/42/EC on 30 December 2009, it ceased to be a harmonised Standard. This means that technically there isn’t a standard for palletisers and depalletisers.

While this means that palletiser owners cannot be prosecuted under EN 415-4, they could still be prosecuted under the Provision and Use of Work Equipment Regulations (PUWER), or machinery suppliers prosecuted under the Supply of Machinery Regulations, which relates to CE Marking requirements. 

While we wait for CEN to publish a revised standard, TÜV SÜD’s advice is to continue using the Standard as it remains ‘best practice’, and shows due diligence on the part of the palletiser owner. However, the failures we see on site are often due to a lack of appropriate internal expertise and physical resource to do an in-depth and correct PUWER assessment of all machinery. With palletiser machinery being on such a large and complex scale, the issue of time and expertise availability is further magnified. 

However, to immediately identify any issues, a thorough PUWER assessment should be completed before new machinery goes into operation. Problems can then be rectified with the manufacturer, so that they or the machinery owner no longer run the risk of a prosecution under the Machinery Directive or PUWER. A decision to ‘make do’ or not invest in the appropriate expertise to run PUWER assessments on palletiser and depalletiser machinery could prove fatal.