Review: PD 5304:2005 'Guidance on safe use of machinery'

BSI has recently published PD 5304:2005, 'Guidance on safe use of machinery' to replace PD 5304:2000 and continue the evolutionary process that began with BS 5304 'Code of practice - Safety of machinery', which many machine builders considered to be the 'Bible' as far as machinery safety was concerned.

Written by leading industry experts and with contributions and support from the Health and Safety Executive (HSE), the latest incarnation has been considerably revised. Nevertheless, it still retains the character of the previous edition, with a wealth of guidance on issues ranging from the selection of protective measures and safeguards through to practical examples of guard design safety circuits.

Updated in line with standards

Generally speaking, the changes bring the new edition up to date with current standards, regulations and technologies. But people who already have PD 5304:2000 will, understandably, want to know what the differences are before they invest 149 in a new copy.

A quick glance through the Contents listing shows that some sections have been removed altogether and others added. However, on closer inspection it can be seen that an amount of material from the previous edition has simply been rearranged. For example, the old Section 10 'Environmental considerations' has essentially been redistributed between the new Sub-Sections 5.2 'Further considerations for safeguards', 5.20 'Hygiene and guard design' and 4.3 'Non-mechanical hazards'.

Indeed, there are several other instances of material being relocated and, to be fair, the arrangement is probably more logical in the latest edition - though it might equally be frustrating for readers who are very familiar with its predecessor.

An important change is that Sub-Section 1.3 'Terms and definitions' has been considerably revised and expanded. And another of the major changes is the introduction of a new Section 10 'Safety-related control systems'. Again, this actually contains material from elsewhere in the previous edition, but it does also bring in some new information and is packed with cross-references to other standards. This is a mixed blessing; on the one hand it clearly implies that the reader should refer to (or buy) several other standards, but at least the reader can easily identify the standards. Another point to note is that Section 10 covers pneumatic and hydraulic control systems as well as electrical control systems - though this is essentially material drawn from the old Section 9 'Interlocking considerations'.

Muting and blanking

Section 8 'Protective devices' (previously entitled 'Safety devices') has also received a significant update. For example, Sub-Section 8.2.3 'Electro-sensitive protective equipment' now includes information about muting and blanking. Furthermore, a new Sub-Section 8.9 'Emergency operation - emergency stop and emergency switching off' is a valuable addition.

While Section 8 has largely been changed to bring it up-to-date with current technologies, Section 9 'Interlocking considerations' has been heavily revised as a result of much of the material from the old Section 9 being transplanted to the new Section 10 'Safety-related control systems'.

Section 5 'Aspects of machine design to eliminate or reduce risk' has also been generally revised (its old title was 'Machinery design'), albeit with a fair proportion of its content copied across from the previous edition.

As might be expected, the Bibliography has grown somewhat. By way of an illustration, the bibliography in PD 5304:2000 ran to over ten pages, but that in PD 5304:2005 stretches to over 22 pages. Each page lists around 24 standards, so it now seems that there are dozens of additional standards with which a machine builder or user might be encouraged to comply.

Conclusion

So is it worth spending 149 to buy the latest edition of PD 5304? Because of the effort that has been put into rearranging the content, the new edition appears more heavily revised than is, in fact, the case. Nevertheless, there are some important additions, especially in relation to 'modern' machinery safety devices such as light curtains. Bearing in mind that the cost of the guidance is similar to the cost of a couple of safety relays - or a fraction of the cost of a safety light curtain - it is probably worth the investment. After all, it will most likely remain 'current' for at least five more years, even if technology, standards and regulations continue to advance in that time.