Neil Dyson, of TÜV SÜD Product Service, highlights the key considerations when reviewing machinery safety, in light of complex legislative framework of inter-related standards and regulations
TÜV SÜD Product Service regularly sees common hazards and issues that have not been adequately addressed by machinery end-users. This is because there is more to ensuring machinery safety than simply complying with the Machinery Directive.
The Machinery Directive defines a machine as:
- An assembly fitted with a drive system other than directly applied manual effort, consisting of linked parts or components, at least one of which moves, and which are joined together for a specific application.
- Machinery that is missing only the components to connect it on site or to sources of energy and motion.
- Lifting apparatus whose only power source is directly applied manual effort.
- An assembly of machines and/or partly completed machinery which, in order to achieve the same end, are arranged and controlled to function as an integral whole.
- Interchangeable equipment which is assembled with machinery or a tractor in order to change its function
Design engineers creating a production line by linking two or more machines must consider the Directive’s requirements for complex assemblies. Even if each individual machine complies with the Machinery Directive, it is the assembly that is now considered to be the machine and must itself comply. Similarly, if modifications are carried out, this is also considered to be creating a new machine, which once again must be shown to comply with the Directive.
The EMC Directive and Low Voltage Directive
The EMC Directive set strict limits for radiated emissions. While a single item of equipment might meet these limits, if you combine multiple items there is no guarantee that the overall emission levels will remain satisfactory.
Equipment operating at voltages between 50v & 1000v AC and 75v &1500v DC must comply with the Low Voltage Directive (LVD). LVD requirements include:
- That the product is electrically safe
- The product is constructed in accordance with accepted good engineering practice
- The product is designed and constructed in accordance with the Principal Elements of the Safety Objectives of the LVD
- Electrical equipment is designed and constructed to ensure it is safe when connected to the electricity supply, by providing a level of protection against electric shock
- Low Voltage Directive
The Pressure Equipment Directive is mandatory for equipment operating at a pressure greater than 0.5 bar.
ATEX Directive and PUWER
The ATEX Directive 94/9/EC provides the technical requirements for equipment intended for use in potentially explosive atmospheres. It therefore covers a large range of manufacturing sites including fixed offshore platforms, petro-chemical plants, mines, and even flour mills.
The Provision and Use of Work Equipment Regulations (PUWER) requires users of work equipment to carry out risk assessment and provide work equipment that is suitable for its intended task and can be used without putting persons at risk. It requires that inspections are carried out and results documented:
- After installation and before being put into service for the first time; or after assembly at a new site or in a new location to ensure that it has been installed correctly and is safe to operate.
- After work equipment has been exposed to any conditions causing deterioration, which is liable to cause a dangerous situation.
- At suitable intervals; and each time that exceptional circumstances have occurred that are liable to jeopardise the safety of work equipment.
While machinery safety is a complex process, the guidance provided in both the Machinery Directive and associated standards mean that there is no excuse for getting this wrong. If in doubt it is important to seek expert advice.