Machine safety: why sticking to standards is a step in the right direction
4 Dec 2016 by Rob Smith
Keeping European law at arm’s length may not be a good thing when it comes to following machine safety standards, writes Robert Smith.
Machine safety is a hot topic. Getting it wrong puts employees at risk and severely hits the pocket of an offending company.
Take Tata Steel, for instance, which recently incurred a £1.98 million fine after two of its employees suffered injuries to the arms and hands.
In the first incident, which occurred on 12 September 2014, a 26-year-old man lost two thirds of his left hand including his middle and ring fingers while trying to clear a blockage on a steel tube manufacturing line, Northampton Crown Court was told in July.
According to the Health and Safety Executive (HSE) which investigated the incident, the injury was caused because the steel tube manufacturing line had unsuitable guarding.
Guarding of dangerous parts of machinery is fundamental in ensuring workers’ safety. HSE will not hesitate to hold those accountable who do not fulfil their legal obligations, especially if that results in someone receiving life-changing injuries
Mark Austin, HSE inspector
The second incident, which took place on 19 February 2015, was also caused by a machine with inadequate guarding. A 52-year-old man lost part of his little finger on his left hand while receiving refresher training.
Speaking after the hearing, HSE inspector Mark Austin said: “Guarding of dangerous parts of machinery is fundamental in ensuring workers’ safety. HSE will not hesitate to hold those accountable who do not fulfil their legal obligations, especially if that results in someone receiving life-changing injuries.”
Machine guard manufacturer Procter says this type of kit must first and foremost be well designed if it is to operate safely and efficiently.
However, in a blog post that appears on its website, Procter points out there is no legal requirement in the UK or Europe to comply with machine-guarding standards.
Despite this, the company advises that compliance with the relevant standards, especially those harmonised to the Machinery Directive, is generally the best way to demonstrate that essential health and safety requirements have been met.
“Compliance with the standards is strongly recommended,” it says.
There are limits
Legislation also comes into play when companies install speed monitoring systems – which are designed to safely control a machine and protect its operator.
However, although machinery can have safe operating speeds that should be adhered to, it is not always straightforward finding out what the permissible safe limits of operation should be, says Martin Kidman, safety specialist at sensor and safety solutions manufacturer SICK UK.
“Whatever your opinion about Europe, there’s no doubt that we are fortunate in having unified safety legislation via the European Union that has set high standards for the rest of the world to follow,” he says.
Unfortunately, the Machinery Directive is long and complex with many clauses and sub-clauses, all of which must be adhered to when designing and building a machine, Kidman explains.
“It would be very difficult for someone to design a machine and simply assume, or even prove, that they have complied with every clause in the Machinery Directive. So the specifications to cover each aspect of the design and manufacture of machines are helped by agreeing standards.”
Kidman adds that harmonised standards across the EU can be used to give purchasers the confidence that a machine meets the requisite safety levels and presumes conformity to the directive – regardless of where it is made.
The specifications to cover each aspect of the design and manufacture of machines are helped by agreeing standards
Martin Kidman, safety specialist at SICK UK
Tony Reynolds, compliance manager at Lorien Engineering Solutions, says when using the Machinery Directive the application of each of the Essential Health and Safety Requirements (EHSRs) is mandatory.
However, he says when taking account of the ‘state-of-the-art’ – which describes a dynamic concept reflecting what can be done at reasonable cost using generally available technology at the time – it may not be possible to meet the objectives set by the EHSRs.
“In these cases the product must, as far as possible, be designed and constructed with the purpose of meeting their objectives,” Reynolds says.
“Although the precise means by which an objective is met is left to the product designer/manufacturer, over time the possibilities and standards for meeting those objectives may change as the ‘state-of-the-art’ for health and safety increases.”
As for the machine safety hazards that standards are designed to help avoid, Reynolds says there are a number that can be difficult to resolve correctly.
Currently, challenges relating to the Safety Related Parts of Control Systems (SRP/CS) and the validation of control systems are causing headaches throughout industry, he says.
“The purpose of the validation process is to determine the reliability (known as the Performance Level PLr), confirm that the design of the safety-related parts of the control system fall within the overall safety requirements of the machinery, and demonstrate that each safety-related part meets the requirements of the standard.”
Although the precise means by which an objective is met is left to the product designer/manufacturer, over time the possibilities and standards for meeting those objectives may change as the ‘state-of-the-art’ for health and safety increases
Tony Reynolds, compliance manager, Lorien Engineering Solutions
Reynolds says the applicable standards – EN ISO 13849-1:2015 and EN ISO 13849-2:2012 – require a validation plan that identifies and describes the requirements for carrying out the validation process for the specified safety functions, their categories and performance levels.
“In addition, the designer of the control system must conduct a risk assessment to determine the required performance level. “In most cases, manufacturers will use either SISTEMA or Pilz PAScal software to validate their control systems.”
The ergonomics of safety
As part of the modernisation of manufacturing facilities, industrial automation has become invaluable, says Robert Holloway, head of order fulfilment at parts supplier European Automation.
The undeniable benefits of increased productivity, improved efficiency and a reduction in costs have meant that automation has quickly secured its place in manufacturing operations.
Although the use of such advanced mechanisation has increased on the factory floor, workers still play a vital role in operations. For this man-and-machine collaboration to succeed, it’s important to design and create an appropriate and effective level of interaction between staff and technology. This is where industrial ergonomics comes in.
Good ergonomics applies design principles to co-ordinate the devices, systems and conditions in a factory with the requirements of the workers. By improving individuals’ well-being and easing navigation, good ergonomic design can improve the performance of a system and its workers.
Already, manufacturers are opting for automated equipment to speed up and improve their productivity. But implemented into an ergonomically- designed environment, this increased productivity can be taken a step further.
For example, adjusting the body and height of workspaces can not only reduce the risk of injury, but also improve staff motivation by giving them more freedom to move. What’s more, creating easier reach zones for employees can dramatically speed up production.
Even simple changes, such as improving the lighting and temperature for staff, are easy ways to minimise potential accidents.
Inevitably, when organisations add industrial automation to the equation, health and safety becomes an even greater concern. Organisations will strategically place dangerous automated machinery outside the workspaces of employees.
But by implementing intelligent equipment such as human machine interfaces (HMIs), workers can gain a greater view of the processes performed by machinery without having to get up close and personal.
