Machine guards, risk assessments and gating equipment offer essential protection – but these crucial tools are often overlooked, writes Robert Smith.
Failure to adequately protect process sector workers from moving parts and manufacturing equipment can lead to disaster. In 2016, Tata Steel was fined almost £2 million after two workers suffered injuries to their hands in two separate incidents involving machinery.
In the first incident, an employee lost two-thirds of his left hand and his middle and ring fingers while trying to clear a blockage on a steel tube manufacturing line. In the other, a worker lost part of his little finger when his left hand was caught while receiving refresher training on a piece of equipment.
An investigation by the Health and Safety Executive (HSE) revealed both incidents were largely the result of unsuitable and inadequate machine guarding.
We would offer a risk assessment of a firm’s plant and equipment, focusing particularly on regulations four to 24, and would advise a new assessment be conducted if the process within a plant is altered in any way
Martin Palmer, training manager, Pilz
Following a hearing into the incidents, HSE inspector Mark Austin said: “Guarding of dangerous parts of machinery is a fundamental of 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.”
Then in July last year, baking company Warburtons received a similar fine – of £1.9 million – after a worker’s arm was trapped against a running conveyor belt. Again, HSE inspectors said the incident could have been prevented had the machine been sufficiently guarded.
Risk assessments are vital
Yet despite these sobering reminders about what can happen within the process sector, many engineering firms are failing to acknowledge the risks.
Companies that have been fortunate enough to avoid such incidents tend to get complacent. And while every piece of equipment within their plant might be in perfect working order, there is no guarantee it will remain in that condition.
That is according to Martin Palmer, training manager at automation and safety solution provider Pilz, who argues that people who have not had a problem in the past, typically do not expect to have a problem in the future, adding that such a narrow view can cause issues.
There is also a lack of knowledge among engineers about machinery safety, which, again, can lead to incidents. That’s where companies like Pilz come in, Palmer says.
“We can provide services such as education through training courses and conducting risk assessments on a company’s behalf.”
When a piece of kit is designed, it requires a risk assessment, to help determine safety functions required and what level of performance is needed for each. Existing equipment, and the plant as a whole, should be risk assessed regularly too, advises Palmer.
The importance of PUWER
He says Pilz’s risk assessments typically focus on benchmarking against the regulations set out in the Provision and Use of Work Equipment Regulations 1988 – referred to as PUWER.
According to the HSE, PUWER place duties on people and companies who own, operate or have control over work equipment, and also places responsibilities on businesses and organisations whose employees use work equipment.
Palmer says: “We would offer a risk assessment of a firm’s plant and equipment, focusing particularly on regulations four to 24, and would advise a new assessment be conducted if the process within a plant is altered in any way. This should help discover if any new hazards have been introduced to the process or manufacturing line.”
The increased use of robotics, either traditional or collaborative, could mean that people are taken away from more dangerous areas, with robots providing a safer conduit
Paul Taylor, manager for machinery safety, TUV SUD
But PUWER does not stipulate a timeframe for when general plant and equipment should be assessed, rather it is a requirement to evaluate on a periodic basis to help ensure these types of machines are adequately maintained.
However, in some legal requirements in PUWER, for types of machine that are not considered general equipment, there are very specific timescales for inspections and the checking of safety functions, Palmer says.
The environment can also have an impact on inspections, he adds. “If you have a piece of equipment that is in a very clean environment, such as a pick-and-place robot that’s well protected, fully compliant and generally being operated where there is minimal risk of mechanical damage, then the inspection will be a lot less rigorous and frequent.”
This is in comparison to a piece of equipment that could be affected by a lot of moving parts, which could cause damage to the machine or its guarding. It is also a reason why regulators do not set stricter rules.
Ignorance is not bliss
Failure to ensure equipment is in good working order cannot simply be blamed on a lack of knowledge or ignorance. Yet for some, the easier options – to rest on your laurels and, perhaps unknowingly, overlook machinery safety – are still frequently chosen by plant owners.
Statistics from the HSE reveal almost 700,000 non-fatal workplace injuries were reported in the UK between 2016 and 2017. Of these, 4% were the result of contact with machinery. This equates to around 28,000 injuries in the space of 12 months.
For the UK’s manufacturing sector, the statistics are even more worrying. According to the HSE, 60,000 manufacturing workers suffered non-fatal injuries between 2016 and 2017. Of these, 24% were either struck by an object or came into contact with a machine.
The sector also suffered 19 fatal injuries in this time. Contact with machinery made up almost 20% of these incidents, while 14% were the result of being struck by an object.
While it is not clear if inadequate guarding played a part in any of these tragic incidents, it is certainly a possibility.
However, workers will, at times, still have to go through vital safety barriers, meaning such intervention must proceed carefully.
Creating a safer working environment
As a result, more contemporary technology is being adopted into machine safety protocol, with integrated systems becoming increasingly commonplace. This type of technology can be combined to allow an operative to access guarded areas only when safe to do so. Palmer agrees safety components complement physical guards where there may be access to danger areas.
Safety components include: mechanical tongue interlock switches, non-contact magnetically actuated interlock switches, non-contact RFID actuated interlock switches, solenoid-based guard-locking switches, modular gate access devices and trapped key systems.
In some cases physical guards can impede production and other technologies can be deployed which are based upon fail-safe detection of personnel encroachment into danger areas
However, Palmer adds one should not forget that the signals to and from these switches must be connected to fail-safe control devices such as safety relays, safety controllers, safety PLCs or PLCs with fail-safe sections.
“In addition, there is a requirement to have emergency stop devices to complement the guards. In some cases physical guards can impede production and other technologies can be deployed which are based upon fail-safe detection of personnel encroachment into danger areas. These include light curtains, laser scanners and other vision based protection devices, for example.”
Guarding to stand down?
Speaking previously to Process Engineering, Paul Taylor, manager for machinery safety at TUV SUD, predicted that the use of technology in the process sector was only likely to increase, and could change the ways factories look and work in the future. This could result in a slight reduction in guarding equipment.
Operatives could instead wear a badge so if they went close to a machine, it would slow or stop. “Increased use of robotics, either traditional or collaborative, could mean that people are taken away from more dangerous areas, with robots providing a safer conduit.”
