Jeremy Procter, Convenor of the European Standards Committee responsible for Machine Guards, and Managing Director of Procter Machine Safety, look at the standards relating to the safety of food and drink machinery.
The easiest way for designers to demonstrate that machines comply with the requirements of the Machinery Directive and corresponding national regulations is to apply the appropriate standards. Three types of machinery safety standards are published: type A is basic safety standards such as EN ISO 12100-1 ‘Safety of machinery – Basic concepts, general principles for design. Part 1: Basic terminology, methodology’; type B are ‘Group’ safety standards that address one aspect of machinery safety that is applicable across a range of machine categories, such as EN ISO 13849-1 ‘Safety of machinery, Safety-related parts of control systems, Part 1: General principles for design’; and type C standards relate to specific machines or categories of machine, such as BS EN 453 ‘Food processing machinery. Dough Mixers. Safety and hygiene requirements.’
Assuming that standards are being used as the route to compliance with the Machinery Directive, machines will be designed in accordance with type A standards, plus type B and type C standards where appropriate. Note, however, that a type B or type C standard will take precedence if it deviates from any provision within a type A standard.
Because of the potentially hazardous nature of food machinery, in that manual intervention is often required for loading, unloading, operation and cleaning, several type B standards and numerous type C standards have been published. Packaging machinery, which is widely used in the food industry, is similarly covered by type B and type C standards. In addition to the published standards, others are in development and available as drafts.
The main type B standard for food machinery is BS EN 1672-2:2005 ‘Food processing machinery. Basic concepts. Hygiene requirements.’ However, another important standard currently in development is prEN 1672-1 ‘Food processing machinery. Basic concepts. Safety requirements.’
Dozens of type C standards have been published or are under development for various categories of food machine. These include meat machinery; fish processing machinery; cereal processing machinery; pasta machinery; bakery machinery; catering machinery; edible oils and fats machinery; and dairy machinery.
As an example of these standards, take BS EN 453:2000 ‘Food processing machinery – Dough mixers – Safety and hygiene requirements.’ As the title suggests, this contains requirements relating to both hygiene and safety, which includes guarding. However, UK designers working to this standard need to be aware that the HSE (Health and Safety Executive) objected to the draft standard to the extent that the UK voted against the proposed standard at the formal voting stage because of concerns about guarding. In particular, an excessive opening of an interlocked guard to enable an operator to take a dough sample during the kneading process could give access to the hazardous zone. Furthermore, the standard does not make a distinction between single- and double-arm mixers, the latter being considerably more hazardous due to the scissor action that presents a trapping and sharing risk. As a member of CEN, the UK was obliged to publish EN 453:2000 as a British standard (BS EN 453:2000), but the BS version includes a National Foreword that draws readers’ attention to the standard’s deficiencies. Designers should, therefore, take great care when working with this standard.
It is rare for the HSE to object so strongly to a machinery safety standard, and standards remain the best route to compliance. Unfortunately, the HSE’s analysis of injuries in the food and drink industries suggests that there is scope to improve machinery safety. According to the HSE, one-quarter of all manufacturing injuries occur in the food and drink industries. The HSE’s analysis reveals that machinery was involved in 8 percent of the over 6000 injuries in the food and drink industries during 2006/07; although this is a relatively small proportion, these accidents were often severe or even fatal. Over the last 10 years, there have been 35 fatal injuries in the food and drink industries. The biggest single cause of fatal injuries is machinery (more than 30 percent of fatalities). A particular cause of concern is workers entering machines for cleaning or maintenance purposes and being trapped when the machine starts unexpectedly. This type of accident can be prevented if a safe system of work with lock-off procedures is in place.
Looking in detail at other types of accident, conveyors account for 30 percent of injuries; over 90 percent of these injuries involve belt conveyors, and 90 percent of conveyor accidents involve recognised hazard points such as in-running nips, transmission parts and trapping points between moving and fixed parts. Furthermore, 90 percent of conveyor accidents occur during normal foreseeable operations including production activities and clearing blockages.
Advice and guidance on machinery safety in the food and drink manufacturing industry is available via the HSE’s website, and a full list of standards harmonised to the Machinery Directive – including the type C standards – is available on the European Commission’s website.
Various useful documents and utilities can also be downloaded free of charge from the Procter Machine Guarding website. As well as a Risk Assessment Calculator and a Guide to Machinery Guarding Standards, there is a Safety Distance Calculator, a Guide to the New Machinery Directive, and, in case of an accident, a Machine Accident Investigation Kit. To download free copies of these, go to the Downloads section of the Procter Machine Safety website. Alternatively, request them by emailing info@machinesafety.co.uk