In this article, Hollie Dixon from leading machinery safety specialist Euchner UK highlights some of the often-overlooked aspects of machinery risk assessments.

Did you know that it is a legal requirement for every machinery manufacturer to carry out a risk assessment before anything is placed on the market? However, even when risk assessments are undertaken, they are often not of a suitable standard. Guidelines on risk assessments can be found in EN ISO 12100, a standard that describes basic risks that can occur and identifies steps with which a risk assessment can be carried out.

Content of a risk assessment

The risk assessment itself consists of the sections:

·       Risk analysis consisting of:

1.     Determination of the limitations of the machine

2.     Identification of the hazards

3.     Risk estimation

·       Risk evaluation

Risk assessment using EN ISO 12100

One of the central points of the standard is a general strategy on how to reduce the risk on a machine and here, the following three-stage process must be applied:

Step 1: The risk of injury must be reduced as far as possible by means of a suitable design. For example,  spoked wheels and pulleys can be designed with a solid infill to the prevent trapping and shearing fingers and limbs.

Step 2: If all hazards cannot be eliminated or adequately minimised with Step 1, technical measures for risk reduction must be applied where applicable. Generally, these measures involve physical guarding with control system interlocking to suit the risk/hazard involved. The safety related control functions also require an assessment to determine safety integrity. EN ISO 13849-1 gives further information on this aspect.

Step 3: Additional protective measures are the last option within the hierarchy requiring users of the equipment to protect themselves from harm through the use of PPE, training and warning signs. Unfortunately, there are too many instances where designers of equipment jump straight to this step without safeguarding or considering designing the hazard out.

This process should be well documented and included as part of the Technical Construction File (TCF) for all manufacturers of machinery and equipment covered under the Machinery Directive.

Machinery Lifecyle

EN ISO 12100 also provides guidance on which phases of the life of a machine must be considered and which of the various hazards must be assessed. These phases of life include transport, assembly and installation; commissioning; use; and dismantling, disabling and scrapping.

The erection and dismantling of a machine are included in the phases of life but often overlooked by many machine manufacturers, despite there being significant hazards during these phases, including:

·       Setting up

·       Teaching/Programming

·       Start-up and stopping the machine including emergency stopping

·       All modes of operation

·       Feeding and removal of the material from machine

·       Recovery of operation from jam or blockage

·       Restarting after unforeseen stopping

·       Fault finding/troubleshooting

·       Operator interventions

·       Cleaning and housekeeping

·       Maintenance (Preventative and corrective)

During all these tasks, hazards in the risk assessment must be taken into account and, if there is a danger, it must be reduced in accordance to the risk assessment. An additional point to the risk assessment that is frequently overlooked is the unintentional behaviour of an operator or the reasonably foreseeable misuse of a machine. Malfunctions on a machine, due to the failure of a component for example, are also to be considered.

It is not uncommon for hazards originating from a machine or installation to be missed during the risk assessment. For this reason, there are also examples for the various possible hazards in the Annex to the standard, including (but not limited to):

·       Crushing due to moving elements

·       Crushing due to lack of stability of the machine or part of the machine

·       Electrical shock or electrocution due to electrical equipment, parts of which become live under fault conditions.

·       Permanent hearing loss due to prolonged exposure to noise

·       Respiratory disease due to inhalation

·       Musculoskeletal disorders, e.g. repetitive activity

·       Burns due to contact with excessive temperatures or chemicals

Taken altogether, this can be a very complex task for the design engineer although there is wide range of external support available including training, risk assessments and safety concept design services from companies like Euchner.

Methodology for risk estimation

There are various factors that define the risk in a danger zone on a machine. Primarily, there is of course the possible extent of the harm. However, a risk is lower if the exposure to a hazard is only infrequent or brief, for example with fully automated machinery. The second factor is the frequency and duration of usage. The third factor is whether the person can avoid the hazard because, for example, the motion that causes the hazard is so slow that it is possible to leave the danger zone by simply moving away. A fourth factor is the probability of the hazard actually occurring.

In summary, EN ISO 12100 provides guidelines for the safety of machinery. It is intended to help manufacturers design safe machinery and to assist in the creation of national regulations for the safety of machinery. The standard covers a wide range of topics, including risk assessment, and is meant to help ensure the safety of machinery by reducing the risk of accidents and injuries to workers and other people who may come into contact with machinery.

As part of our feature series on safe machine design, Euchner’s Mark Staples answers some questions on the ISO 14119:2013 machinery safety standard and the procedures for the selection of a suitable interlocking or guard locking device.

What does the standard contain?

The standard describes the selection and usage of interlocking devices with/without guard locking on safety doors, safety covers and other movable safety guards. 

The term interlocking devices refers to safety switches fitted to safety doors that ensure machines/systems safely shut down on opening the door. Interlocking devices with guard locking (guard locking devices) only enable access once the risk of injury is eliminated (e.g. the hazard due to over-traveling machine movements, or machine rundown time due to inertia of moving parts, which could be something as simple as a rotating cutting blade).

The standard’s application, like all safety-related standards of this type, gives machine designers an assurance that the requirements of the Machinery directive are met.

Can it be used to obtain UKCA or CE marking?

To assign UKCA or CE marking to a machine/system, the law as applicable to machinery permits various possibilities, one of which is the use of harmonised standards. If all relevant standards are applied, ‘Presumption of Conformity’ can be assumed. 

One harmonised type B standard is ISO 14119, which is applicable independent of the machine type for the usage of safety switches on safety doors. Machine builders may find it difficult to defend themselves if applicable standards have not been followed and accidents occurred because of this.

What are an interlocking device’s component parts?

The standard defines the term “interlocking guard”, which includes the movable safety guard and the interlocking device. This generally has two parts, the actuator and position switch.

What are the guard locking principles?

ISO 14119 contains four principles of operation for guard locking devices:

1. Spring applied – Power-ON released

This is a closed-circuit current principle in relation to the function of guard locking. It means that guard locking devices are moved to the “locked” position by a spring on the removal of the power. Switching on the power opens the guard locking device.

2. Power-ON applied – Spring released

This principle operates in the opposite manner and is referred to as “electrical guard locking”. It’s an open-circuit current principle.

3. Power-ON applied – Power-ON released 

This is a principle that doesn’t change position on the removal of power. It’s also called the bistable principle. Power must be applied to change it to the other state. As the removal of power doesn’t change the position of the guard locking device, it’s considered a closed-circuit current principle.

4. Power-ON applied – Power-OFF released 

This corresponds to an open-circuit current principle as the guard locking device opens on the removal of the power. Typically used for electromagnets, e.g. on the CEM.

Which principle must be selected?

It’s possible to select from these options for the operation of the guard locking. Two of these are closed-circuit current principles where the guard locking device is closed (locked) in the event of a power failure. A guard locking device for personnel protection must use one of these two principles.

The standard permits a minor exception from this selection only if it can be shown that a closed-circuit current principle is an unsuitable method. The evidence for this will be very difficult to find. Often an open-circuit current principle is chosen for the access to the machine in the event of a power failure. However, this aspect can also be ensured using a closed-circuit current principle guard lock with an emergency release mechanism.

For process protection designers are free to decide which type of guard locking is selected as it doesn’t represent a safety function. The only requirement is that on guard locking devices for process protection, the safety of the interlocking device must not be degraded.

How must a guard locking device be controlled and how is the PL of the circuit determined?

The greatest change in ISO 14119 compared to its predecessor is the requirement to consider the control of guard locking as a safety function. This doesn’t mean that a guard locking device must always be controlled with dual channels with immediate effect, only that a risk analysis must be undertaken to determine the necessary PL. 

Guard locking devices like Euchner’s MGB function differently. These devices have a permanent power supply and the control of the guard locking is undertaken via inputs. Therefore, guard locking is not fully de-energised even on shutting down the two inputs. On these devices, the electronics contribute to the probability of failure of the control chain and a block must be added to the PL calculations.

Is the series connection of electromechanical guard locking devices safe?

Series circuits can be used without problems up to category 1. The situation becomes difficult if diagnostics on the individual safety switch is necessary. The problem here is that with a series connection, faults are masked by other safety switches. Unfortunately, this aspect is often overlooked and can lead to even relatively new equipment having guarding faults going undetected.

Euchner UK Limited has continued its recruitment drive with the appointment of Mark Tsang as a Machinery Safety Consultant. 

Commenting on the appointment, Euchner’s Managing Director (UK&I) David Dearden says: “As a TÜV NORD Certified Machine Safety Expert, Mark Tsang is a well-respected engineer and joins us with extensive knowledge and experience in machinery safety consultancy. He has an extensive portfolio of qualifications covering DSEAR, ATEX, PED and PSSR; combined with expert witness writing and 20+ years’ experience of training and mentoring in engineering consulting.”.

He goes on to say that with the introduction of new standards, the frequent amendments to legislation and the advances in safety technology, including UKCA marking and PUWER inspections, many companies choose to outsource their machinery safety services requirements. “Machine manufacturers and end users must comply with UK and European directives, as well as international standards. Euchner Safety Services can provide you with professional solutions for all aspects of machinery safety, anywhere in the world. We help machine manufacturers and users meet legal safety requirements at every stage of machine and installation life cycles.” says David.

Mark joins Euchner’s already highly-skilled team of machinery safety experts and has all the knowledge and skills required to assess the safety of machines and equipment, identify potential hazards, and offer practical advice to control or eliminate those hazards. This includes conducting risk assessments, developing safety plans and procedures, and providing guidance on compliance with relevant safety regulations and standards.

To book your safety consultation, call Euchner’s Safety Technology Centre on +44 (0)114 256 0123, email services@euchner.co.uk or click https://bit.ly/3OK32oR.

Machinery safety specialist Euchner UK Limited is continuing to strengthen its team with the appointment of Hollie Dixon in a business development role. Hollie’s roles have been product-focussed and customer-facing since joining Euchner, so she is already well-versed on the company and its portfolio of machinery safety products and training solutions. 

Commenting on the appointment, Managing Director (UK&I) David Dearden says: “Hollie’s all-encompassing role helps support our major growth plans by being a key contributor to UK sales and marketing strategies for both products and services for Euchner.

“Her role will include research and analysis of key trends in new and existing markets, collaborating with both internal and external resources on new product launches and working closely with the sales and services teams on growth strategies and the continued development of Euchner’s key accounts network.”

Industrial safety engineering specialist Euchner will use its stand at this year’s PPMA exhibition to launch two new and exciting products – the Industry 4.0 Ready CTS safety switch and CKS2 coded key system – and showcase its extensive range of guard locking products available for common fieldbus connections.

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 switch solutions, by combining the best of both worlds in a single switch while offering maximum flexibility. A key innovation of the compact 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 the switch’s function, allows a single device to perform a wide variety of functions that would otherwise require several switch variants. Its compact dimensions, high locking force of 3,900N and suitability to mount in three orientations ensures the CTS is suitable for use across numerous safety engineering applications.

Combined with highly-coded, transponder-based keys, the new CKS2 from Euchner forms a safe system that meets the highest safety requirements for machine and installation lockout and starting. Thanks to the integrated evaluation electronics and depending on the key used, various safety engineering tasks are possible with the compact CKS2 key system. Additionally, combining it with Euchner’s IO-Link Gateways expands its applications and enables comprehensive diagnostic and communication functions. 

Unlike the CKS, 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.

Commenting, Euchner’s UK&I Country Manager David Dearden says: “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.”

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. 

The MGB2, CKS2 and CTS are just three examples of the safety devices available from Euchner. For further information on these and other machinery safety solutions, the company’s technical and product support team will be on stand E68 at PPMA 2022 from 27th to 29th September.

If there is one area where applications are becoming ever-more complex, it's safety engineering and industrial safety engineering specialist Euchner (UK) Limited has not only kept up with this trend with its Multifunctional Gate Box (MGB) safety door system, but has gone a step further by employing modular design to make its latest version, the MGB2 Modular, fully customisable for maximum optimisation. So, more than simply providing safety door protection, thanks to its modular design the MGB2 Modular lets you implement numerous additional functions including locking modules, extension modules and submodules.

Following its market firsts in PROFINET and EtherNet/IP connection, launch of the the new MBM bus module from Euchner is available in a version that connects to EtherCAT P, which means that every function of the MGB2 Modular can also be used with EtherCAT P. 

The MBM bus module coordinates all the safety, non-safety and diagnostic communication signals between the fieldbus system and MGB2 Modular system components – connected to the MBM directly or via M12 standard cables – with the MGB2 Modular connection technology able to operate up to six locking modules on one MBM bus module for communicating both safety and control signals. Besides fewer devices, the user also requires less on-machine cabling and PLC I/Os, ultimately saving on costly failsafe PLC capacity in the control system.

The locking modules can be equipped with controls including pushbuttons, selector switches, key-operated rotary switches or emergency stop buttons. Submodules allow up to six different control elements in the locking module, with add-on expansion modules available where additional user-controls are required, eliminating the need for separate localised operator control stations and their associated costs and complexities.

Comprehensive diagnostic information in the form of EtherCAT messages and the integrated web server provide a rapid and detailed overview of the device status without having to have specialist software or programming knowledge; and straightforward parameter assignment means that even system replacement during servicing is a simple task requiring only a few minutes to complete. 

Industrial safety engineering specialist Euchner (UK) Limited will use its stand (G120) at this year’s Drives & Controls exhibition to showcase its extensive range of guard locking products available for bus connection networking using protocols including EtherCAT, PROFINET and EtherNet/IP.

One machinery safety solution the company is keen to highlight at the show is Euchner’s MGB/MGB2 (Multifunction Gate Box) which, by integrating modules including the CKS key systems, can go from being a simple interlocking/locking device, to a small control terminal.

Commenting, Euchner’s UK&I Country Manager David Dearden says: “The combination of MGB2 and CKS 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.”

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.

By integrating a CKS (Coded-Key-System) key system module, Euchner’s MGB2 can be used for electronic access control and access management as an alternative to standard, easily-manipulated key switch or password-based systems. For more complex access control or traceability, Euchner offers the EKS (Electronic-Key-System) where each Electronic-Key from the EKS transponder-based read/write system can be setup using the Electronic-Key adapter and loaded with information on specific key owners and their rights/privileges. This allows them to control specific machine functions or contain encrypted process parameters for an installation.

The MGB2, CKS and EKS systems are just three examples of the safety devices available from Euchner. For further information on these and other machinery safety solutions, the company’s technical and product support team will be on stand G120 at Drives & Controls 2022 from 5^th to 7^th April.

Alternatively, please contact Mark Staples on +44 (0)114 256 0123 or mark.staples@euchner.co.uk.

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, industrial machine safety specialist Euchner (UK) Limited has launched Euchner Academy, a portfolio of machine and operator safety courses that has been designed with its customers in mind.

Commenting, Euchner’s UK Sales & Services Manager Mark Staples says: “By bringing Euchner Academy to the UK and opening our new Safety Technology Centre in Chesterfield, we 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 of 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 the all-new Euchner Academy safety technology facility in Chesterfield, with machine safety courses covering subjects including:

PUWER Training

A one-day course covering the content and application of the Provision and Use of Work Equipment Regulations 1998 (PUWER). This course covers the regulations and basics of risk identification and assessment. On successful completion of the course delegates will have an understanding of their legal obligations under PUWER and how to practically apply the legislation in the workplace.

UKCA Marking Training

This one-day course covers the UKCA Certification according to the Supply of Machinery (Safety) Regulations 2008, including the CE to UKCA transition. It covers the contents of the regulations and the implementation of harmonised standards. On successful completion, delegates will have an appreciation of the legal framework involved and an understanding of the route to conformity.

CE Marking Training

A one-day course covering the requirements to obtain CE Certification according to the EU Machinery Directive 2006/42/EC, including the relevant documentation when importing/exporting equipment. This programme covers the contents of the directive and the implementation of harmonised standards. Delegates completing the course will gain an appreciation of the legal framework involved and an understanding of the route to conformity.

Machinery Risk Assessment Training

This one-day course provides practical knowledge and experience on how to conduct a machinery risk assessment in accordance with the relevant standards. The course provides advice on how to identify, quantify and document machine related hazards using suitable templates. A structured risk-reduction methodology is introduced using the principles of ALARP resulting in a thorough knowledge of the process and solutions needed to deliver a comprehensive risk-reduction programme in the workplace.

Safety for Control Systems

A practical one-day course providing hands-on experience of safety-related components and circuits. The course is designed to give the delegate an invaluable understanding of the overall functionality and potential shortfalls of any given safety scheme, resulting in a sound appreciation of the key principles to be used when designing or modifying hard-wired safety-related control circuits.

Safety System Design & Verification

This two-day course will give the electrical designer a thorough understanding of the requirements of the safety standard BS EN ISO 13849-1:2015 – Safety of Machinery. Safety-related parts of control systems. General principles for design and BS EN ISO 13849-2:2012. At the end of the course delegates will have the confidence to design, verify and validate a machinery safety-related control system as well as the knowledge to use the SISTEMA software suite to verify and document their design.

Machine Safety for Operational Personnel

Ideal for occupational health and safety professionals as well as other stakeholders within the company, this one-day course is intended to provide the delegate with a basic appreciation of machinery safety legislation including its importance in the workplace. Course attendees are provided with the knowledge to be able to manage machinery safety through the implementation of safe operating procedures and working practices, to complement existing engineering risk reduction procedures in place.

Euchner Academy also offers bespoke safety training courses to suit the individual needs of your organisation, machinery and personnel. The training delivered during tailored safety courses can cover a broad spectrum of topics, be it exploring machinery safety for specific applications or industries or examining standards and regulations.

For 2022, the Euchner Academy machine safety training calendar is available to download from the company’s website. Delegates wanting to book courses can email services@euchner.co.uk, call +44 (0)114 256 0123 or via Eventbrite at https://lnkd.in/dTDKXbuv.

For further information on our machinery safety engineering training courses visit our training pages at www.euchner.co.uk.

The CTM transponder-coded safety switch from industrial safety engineering specialist Euchner (UK) Limited features evaluation electronics, a bistable locking function and is capable of the control of guard locking via IO-Link communication, future-proofing the device for Industry 4.0 and meaning no separate wiring is needed for the control of guard locking, because the existing communication connection is used.

Commenting, Euchner’s UK&I Country Manager David Dearden says: “As a safety device, the CTM is smart, compact, safe and features everything you need from a guard locking safety switch. However, the IO-Link version brings further benefits to the CTM range by adding the ability to lock and unlock the device over IO-Link communications, coupled with the comprehensive diagnostic data provided by the IO-Link protocol.” 

The evaluation electronics integrated within the CTM allows for simpler wiring and a greater level of detection for connection faults, short-circuits and errors. Additionally, it allows the guard locking safety switch to be wired separately or in series whilst maintaining high levels of performance, up to and including Category 4/PLe according to BS EN ISO 13849-1 and BS EN ISO 14119, ensuring the highest safety level category despite the CTM’s compact size.

The bistable locking function can prevent the deactivation of the activated guard locking in case of a power failure, ensuring that guard locking remains in its current state if the power fails or the installation is switched off. It can also prevent personnel from unintentionally locking themselves inside a potentially unsafe area if the safety door is open in the case of power failure or if the machine is switched off, meaning no additional escape release is required.

The highly compact IO-Link version of the CTM is suitable for numerous safety applications including the protection of personnel and processes, with a hygienic version consisting exclusively of food-safe materials also available for the packaging and food sectors. Featuring a locking force of 1,000N (and integral adhesive force of 25/50N) and an innovative safety ball actuator, the CTM is ideal for discreet installation on small, lightweight doors and flaps with a pivoting radius from 150mm.

For further information on the new IO-Link version and other models from the CTM guard locking safety switch range visit Euchner.co.uk, email sales@euchner.co.uk or call the technical and product support team on +44 (0)114 256 0123.