David Dearden, UK&I Country Manager for safety specialist Euchner, examines the engineering challenges for protecting people and the machinery commonly used throughout the engineering sector.

Although not always ideal, maintenance operations often require access to dangerous parts of equipment and preventing inadvertent start-up or reducing hazards to an acceptable level needs to be considered. The Lock-Out-Tag-Out system is well established, but the long walk back to the control panel to place the padlock may provide motivation to ignore safety procedures and ‘risk it’. Using local interlocking devices incorporating a local padlock ‘lock-out’ facility (a number of interlocks can accommodate up to six padlocks on a single device), the likelihood of an operator side-stepping safety procedures in place is greatly reduced.

The ability to ‘lock-out’ is great when operators recognise the danger to themselves or others, but what do you do when they, or maintenance staff, try to deliberately override an interlocking system, often to make things easier for themselves? The most common method of overriding a guarding system is using a spare actuator (key), tricking the guarding system into believing the door is closed. This is easily overcome by using RFID ‘coded’ actuators paired to the safety switch – only one actuator can be ‘paired’ at a time, and if the operator tries to use a different actuator, the machine won’t run.

“Euchner was responsible for developing the first RFID locking guard switch, so knows a thing or two about preventing defeat or manipulation of safety systems. With greater focus being placed on this subject within the relevant safety standards, including BS EN 14119, it’s vitally important all equipment manufacturers and end-users consider their existing arrangements are adequate,” said David.

Some may feel the use of electronic safety devices unsuitable for arduous applications, but these devices can handle pull-out forces up to 8KN (much more than even the strongest person could manage), often use vibration-tolerant encapsulated solid-state failsafe electronics and achieve very high ingress protection ratings, including IP65, IP67 & IP69.

For example, the all-new, one-fits-all CTS is Euchner’s first FlexFunction device and expands the company’s product range by sitting between the all-round CTP and specialist CTM safety switches by combining the best of both worlds in a single switch while offering maximum flexibility. Its compact dimensions, high locking force of 3,900N and suitability to mount in three orientations ensure the CTS is suitable for use across numerous safety engineering applications. A key innovation of the CTS – which is IO-Link compatible and Industry 4.0 ready – is the company’s new FlexFunction feature that, by using the transponder-coded actuator to determine a switch’s function, allows a single device to perform a wide variety of functions that would otherwise require several switch variants.

Another new solution from Euchner is the compact CKS2 key system which, combined with highly-coded, transponder-based keys, forms a safe system that meets the highest safety requirements (such as category 4 / PL e according to EN ISO 13849-1) for machine and installation lock-out and starting. Thanks to the integrated evaluation electronics, and depending on the key used, various safety engineering tasks are possible with the CKS2. Additionally, combining it with Euchner’s IO-Link Gateways expands its applications and enables comprehensive diagnostic and communication functions.

The CKS2 can be integrated as a module within Euchner’s Multifunction Gate Box MGB2, expanding the functionality of the simple door interlocking solution to a small control terminal with access control. “The combination of MGB2 and CKS2 can be used across multiple sectors and for numerous applications to ensure process efficiency, create access rights flexibility, increase personnel and process safety, safeguard product quality and create transparency and traceability,” added David.

The MGB2 is a unique interlocking or guard locking system for the protection of safety doors on machines and systems that, thanks to its modular approach, is more than simply a safety switch or bolt and offers a vast array of safety functionality. By incorporating additional safety modules to the MGB2, machine builders can include numerous functions, including guard locking, escape release, start/stop, emergency stop, etc. Its modular design also means the MGB2 can remove the additional need for a separate operator panel. And with networking opportunities available, it also reduces wiring and installation time.

However, the selection of safety interlocks is only part of the story. Plant and equipment used in manufacturing are often extremely dangerous, and therefore the safety-related control system used to safeguard many of the dangerous parts needs to be designed to meet a high Performance Level (PL) and detect faults when they occur. It’s no good only finding out your guard interlock has failed when the machine doesn’t stop on opening the guard door.

This is one of the most common issues Euchner encounters on site, with machinery operators not aware of their responsibilities and risk assessments that haven’t looked thoroughly enough into the safeguarding measures being provided by a particular safety control system.

“Many site-based risk assessments highlight the safeguard measures fitted to a machine, such as interlocks, pull-cords, etc., but has someone actually assessed the design of the safety-related control system behind the devices?” commented David. “The standards, including BS EN 13849-1, assist in the process of determining the PL required for the control system protecting the hazard. And while it’s sometimes seen as too complex, there’s plenty of help from companies, including Euchner, to assist with this much-too-often missing step. The safety manager needs to ensure that safety-related control systems have been designed and verified irrespective of how much functional testing is taking place during the working week.”

The functional test often used at the start of a shift only shows the system is working at that time; it doesn’t guarantee the system will operate the next time it’s called upon, which may be when someone’s life is depending on its operation.

However, not all applications are the same, and it’s always important for the correct components to be selected for any given application.

Another vital consideration is operator/personnel training because, with over 600,000 workers injured in workplace accidents in the UK annually (equivalent to over 2,300 injuries per working day), the cost estimate to the UK in relation to these accidents in 2020 was over £5.6bn.

In a bid to play its part in reversing these statistics, Euchner’s training division, Euchner Academy, has a portfolio of machine builder and operator safety courses designed with its customers in mind.

As David explained, by bringing Euchner Academy to the UK, the company can continue to help manufacturers and users meet legal safety requirements at every stage of machine and installation life cycles: “Customers can strengthen their skills, knowledge and understanding of machine safety engineering via Euchner Academy’s comprehensive and interactive machinery safety training courses, which cover aspects including Risk Assessment and Safety Design, PUWER Inspection, UKCA/CE Marking and Safety Control System Design, as well as bespoke courses to suit individual employee and organisational requirements.”

Machine operators attending Euchner Academy approved training courses will strengthen their skills, knowledge and competency in industrial machinery safety. In addition to the theory, there’s a range of Euchner courses that are supported by hands-on, practical sessions that lead to a greater level of understanding compared to other purely academic programmes. As well as gaining the valuable skills required for their role, operators attending Euchner training courses are also helping to promote a safer workplace for everyone.

Standard training courses can be delivered at a customer’s own site or preferred location, or at Euchner’s Safety Technology Centre in Chesterfield. Euchner Academy also offers bespoke safety training courses to suit the individual needs of an organisation, machinery and/or personnel. The training delivered during tailored safety courses can cover a broad spectrum of topics, be it exploring machinery safety for specific applications/industries or examining standards and regulations.

This article shows that by focussing on good practice with suitable equipment and the right training, it’s possible to achieve increased plant efficiency and operate a safer site, quashing the long-considered opinion that machinery safety reduces throughput – and not even considering the distressing consequences of not getting plant safety right in the first instance.

www.euchner.co.uk