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September 22, 2015

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PUWER

PUWER: Provision and Use of Work Equipment Regulations

Provision and Use of Work Equipment Regulations (PUWER) came into force on 5 December 1998 and was formerly known as PUWER98.

The main objective of PUWER is to ensure the provision of safe work equipment throughout the lifetime of its use, regardless of its condition, age or origin.

The regulations require that machinery provided for use at work is:

  • Suitable for its intended use
  • Safe for use – including keeping it maintained in a safe condition with regular inspections to ensure it is installed correctly and that its level of safety doesn’t subsequently decline
  • Used only by people who have received adequate training, instruction and information
  • Accompanied by suitable health and safety measures, such as protective controls and devices
  • Used in accordance with specific requirements – mobile work equipment and power presses

PUWER is comprised of 37 regulations and is split into 6 parts; within this article we will explore Part 2 – Regulation 18 Control Systems in detail, covering the changes made to the ACOP in November 2014 and how it can be applied.

Regulation 18 deals with taking realistic and practical allowances into account when choosing or specifying control systems, and not increasing risk when the control system is operating, either directly or indirectly, by impeding the operation of other safety measures; not increasing risk if a control system fails or loses its power supply.

This regulation states that every employer shall ensure, so far as is reasonably practicable, that all control systems of work equipment are safe, and are chosen making due allowance for the failures, faults and constraints to be expected in the planned circumstances of use.

PUWER

Failure of any part of the control system or its power supply should lead to a ‘fail-safe’ condition. Fail-safe can be more correctly and realistically called ‘minimised failure to danger’ where the minimisation can actually be quantified as a “probability of dangerous failure per hour”, or PFH.

This should not impede the operation of the ‘stop’ or ‘emergency stop’ controls. The greater the risk, the more resistant the control system should be to the effects of failure. Bringing a machine to a safe halt may achieve the objective. Halting a chemical process, however, could create further hazards. Care should be taken to fully assess the consequences of such events and provide further protection, for example standby power plant or diverting chemicals to a place of safety. It should always be possible to recover to a safe condition.

Regulation 18 mentions the standards BS EN 60204-1, BS EN ISO 13849-131 BS EN 62061 which provide guidance on design of control systems so as to achieve high levels of performance related to safety. Importantly, though they are aimed at new machinery, they may be used as guidance for existing work equipment as “state of the art” guidance.

What’s new?

What is new here is the fact that both functional safety standard BS EN ISO 13849-1 (first published in 2006) and BS EN 62061 (first published in 2005) are now available; at the time that the previous version of PUWER in 1998 was released, both standards were only in preparation. EN 60204-1 was already around in 1998. So what are these standards and when would you apply them?

BS EN 60204-1 is a standard harmonised to the Machinery Directive and the Low Voltage directive, and is titled: “Safety of machinery. Electrical equipment of machines. General requirements”. It is intended to cover the electrical safety aspects of machines. This includes safety requirements for electrical, electronic and computer controlled equipment and systems for machines. It gives specific instructions for the safe maintenance of the point where electrical or electronic equipment connects to the machine i.e. at the main machine isolator connecting the machine to the electrical supply; it refers to machinery that operates with nominal supply voltages below 1,000Vac or 1,500Vdc, or with nominal supply frequencies below 200 Hz.

When it comes to the safety related controls on machines (systems containing safety relays/controllers, interlocked guards, two hand controllers, safety mats, light curtains, emergency stops and the like) there is choice between BS EN ISO 13849-1 (with part 2 for validation) and BS EN 62061. Which you use will depend upon the application.

BS EN ISO 13849-1 is harmonised to the Machinery Directive, and is titled: “Safety of machinery. Safety-related parts of control systems. General principles for design”. It provides safety requirements and guidance on the principles for the design and integration of safety-related parts of control systems (SRP/CS), including the design of software. It was developed as the direct replacement for its predecessor EN 954-1 (with its attendant categories B, 1, 2, 3 and 4 for SRP/CS). For these parts of SRP/CS, it specifies characteristics that include the Performance Level (PL a – e) required for carrying out safety functions.

The PL is based upon not only the old categories of EN 954-1 but also parameters including Diagnostic Coverage (DC), failure rates expressed at Mean Time to Dangerous Failure (MTTFd) and steps taken to reduce Common Cause Failures (CCF). These four factor combine via look up tables (such as one found in Annex K1 of the standard) to form a Probability of Dangerous Failure per Hour (PFH), the order of magnitude of which corresponds to a particular Performance Level (e.g. 10-7 – 10-8 = PL e). It applies to SRP/CS, regardless of the type of technology and energy used (electrical, hydraulic, pneumatic, mechanical, etc.), for all kinds of machinery. It is recommended that EN ISO 13849-1 is used primarily for the design of low complexity SRP/CS.

BS EN 62061 (also harmonised to the Machinery Directive) is titled: “Safety of machinery. Functional safety of safety-related electrical, electronic and programmable electronic control systems”. It gives best-practice recommendations for the design, integration and validation of safety related electronic control equipment for machines – just like EN ISO 13849-1/-2. Rather than specifying Performance Levels it specifies a range of Safety Integrity Levels (SIL 1 – 3) for carrying out safety functions.

The SIL for a safety related control function comprises the architecture (A, C, B, D which are almost equivalent to categories 1,2,3 and 4 of BS EN ISO 138491), Hardware Fault Tolerance (HFT), Safe Failure Fraction (SFF), Diagnostic Coverage (DC) , steps taken against Common Cause Failure (CCF and a beta-factor), test intervals (T1 and T2) and failure rates (expressed as lambda); when these factors are combined in specific equations the result is a Probability of Dangerous Failure per Hour (PFH) the order of which correlates with a particular SIL (e.g. 10-7 – 10-8 = SIL 3). It applies to the safety related control functions (SRCF) which are electrical, electronic and programmable electronic onlyit can not be applied to non-electrical/electronic systems, and this is perhaps the key difference in scope between EN ISO 13849-1 and EN 62061.

The term SIL actually comes from a much broader functional safety standard BS EN 61508 which describes in detail the entire lifecycle for managing safety related controls from cradle to grave of any system be it a device, software tool, a petrochemical plant, rail traffic management system and so on; it is so big that sectorial versions exist for particular branches of industry. BS EN 62061 is such a sectorial version.Other sectorial versions include BS EN 61511 for industrial processes (e.g. petrochemical plants) or EN 61513 for nuclear. Hence, in these particular sectors (and others which use SIL), from a Functional Safety Management point of view, it may be attractive to use EN 62061 for machines

So the reasons for using EN ISO 13849 include the ease of migration from EN 954-1 and its applicability to all systems regardless of source of energy, especially where they’re not complex.

EN 62061 is a more rigorous standard, it lends itself to more complex applications (as long as they do not include non-electrical sources of energy), and it may appeal to those already using SIL-rated systems (for example in the process industries) who are familiar with the BS EN 61508 lifecycle.

Work is currently in hand within a standards working group to merge these two functional safety standards into a definitive single standard within the next few years.

David Collier CMSE®, is business development manager at Pilz Automation Technology

Understanding the basics of machinery guarding

Employers have legal obligations under:

  • Provision and Use of Work Equipment Regulations (PUWER) 1998
  • The Health and Safety at Work etc. Act 1974
  • The Management of Health and Safety at Work Regulations 1999
  • Other relevant legislation includes The Supply of Machinery (Safety) Regulations 2008 which apply to suppliers (not users) and The Enterprise and Regulatory Reform Act 2013

Due to the risks associated with operating machinery, the courts place a higher duty of care on employers. If there is a risk of foreseeable injury, has the employer taken reasonable steps to minimise and/or reduce the risk of injury? Such reasonable steps are considered in the hierarchy of machinery guarding.

The hierarchy of machinery guarding

In order to decide on the most appropriate guarding for different parts of the machine, it is essential to undertake and document a formal risk assessment to establish risk.

A machinery risk assessment will typically involve identifying significant hazards and for each one, evaluating the likelihood of occurrence, frequency of exposure, degree of possible harm and number of persons at risk. Having identified which risks need to be reduced, suitable safeguards can be considered. It is then essential that the risks are reviewed to establish whether controls have, indeed, sufficiently reduced the risks.

Your control strategy should follow the Hierarchy of Machinery Guarding as follows:

  • Fixed enclosed guards;
  • Other guards or protection devices such as interlocked guards and pressure-sensitive mats;
  • Protection appliances such as jigs, holders and push-sticks; and
  • The provision of information, instruction, training and supervision

Fixed guards should remain in place at all times, except when they need to be removed by authorised and competent persons for the purpose of maintenance. Interlocked guards and devices such as pressure-sensitive mats and safety light curtains should be considered where fixed guards would not be practicable because they would hinder normal operation of the machine.

It’s worth noting that just because machinery carries the CE mark, this is no indication that the machine is safe or compliant with UK regulations. Employers must carry out a thorough risk assessment.

Effective health and safety is usually delivered by an integrated package of measures that take account of the hardware (guarding), the systems (for intervention, such as lock off and isolation) and the human factors (understanding what goes on and how to maximise compliance). These measures are interdependent and should be treated as such in the assessment and management of risk.

Provision and Use of Work Equipment Regulation articles

Facilitating safety in the loading bay

Operators must stay alert to all safety regulations and practice, particularly in a loading and unloading environment, Thorworld Industries Managing Director John Meale tells SHD Logistics Magazine.

Fine for manufacturer after serious injuries to worker

Emtelle UK Limited, a manufacturer of plastic tubing and blown fibre tubing for telecoms and water piping, has been fined after an employee suffered serious injuries to his left hand when it came into contact with the exposed clamp of a socket machine.

Worker’s hand amputated in bagel machine

A bakery has been fined after an employee amputated his right hand on a bagel production line.

£20K fine after worker suffers serious back injury in ‘avoidable’ crush incident

A powder coating company has been fined after a worker in a factory suffered shattered lumbar vertebrae and had to be kept in a lying down position on his back for two weeks in hospital.

Abrasive materials and certain chemicals can ‘shorten the life of important components’

Is your site damaging your equipment? CFTS warns that work equipment used for heavy-duty operations may require more frequent Thorough Examinations than owners think.

‘Poor lift truck inspections could pose risk to life’

Thorough Examinations should be completed by qualified engineers, says CFTS — the body behind the national standard.

Manufacturer fined after an agency worker was dragged into a press roller

A manufacturing company has been fined after an employee’s arm was dragged into a press roller.

Companies advised to check paperwork on used forklifts

Companies purchasing or hiring used forklift trucks are being urged to make sure that they see a valid Thorough Examination Report for every machine they bring on site, says the body behind the UK national standard.

Fine after firm breaches equipment regulations

A manufacturer of swimming pool covers has been fined after a worker suffered a degloving injury when his hand got caught between two power driven rollers of an extruder machine.

£50k fine for manufacturer after employee has fingers amputated

A manufacturer of prepared bird feed has been prosecuted after an employee suffered life changing injuries when his hand was trapped in an unguarded rotary valve.

Entanglement risk was ignored by company

An electromagnetic brake manufacturing company has been fined after a worker suffered serious injuries to her arm and hand when she became entangled in a spindle drilling machine.

Engineering firm pleads guilty for failing to safeguard machine

Engineering firm fined £32,000 when worker suffered extensive injuries whilst attempting to light burners on mould making machine, at a Northampton plant.

Company failed to undertake safety checks

A granite worktop manufacturer has been fined after failing to ensure that lifting equipment was examined and maintained to ensure it was safe to use.

Safety management failures and non-compliance

A joinery company has been fined after two separate incidents that led to workers’ fingers being amputated.

Stricter work at height regulation may be the only way to stop avoidable deaths

Falls from height is a major killer of workers in key sectors including construction and agriculture, and the figures show no sign of improvement, as Ken Diable, Managing Director at Heightsafe, explains.

Unguarded machine trapped worker’s hand

A concrete wall blocks company has been sentenced after a worker’s hand was crushed in an unguarded machine.

M & D’s Theme Park fined for poor maintenance that led to ‘catastrophic failure’

Theme park operator M & D (Leisure) Limited has been fined after nine passengers were injured and taken to hospital when a train on one of their roller coasters derailed and crashed to the ground.

Renault safety breach: Workers exposed to dangerous equipment

Car manufacturer Renault has been fined after serious safety breaches relating to faulty vehicle lifts.

Care home fine: 60k fine after resident dies in stairway fall

A family-run care home has been sentenced after a resident fell down a set of stairs and later died as a result.

Two injuries at food manufacturer lead to £200k fines

2 Sisters Group, the food manufacturer, has been sentenced following two separate incidents where workers became trapped in moving machinery.

Company and director sentenced after employee fractures neck in fall from height

The HSE’s investigation found the tower scaffold had not been erected correctly, with no hand or mid-rail in place to prevent falls from height and staff had not been given training in how to properly erect the scaffold.

Printing firm fined after worker pulled into machine

the employee was cleaning a rotating roller at a site in Kettering. The roller was on a production line that makes padded envelopes. The cloth the worker was using got caught and she was drawn into the rollers.

Manufacturing firm failed to maintain machine guarding

A dairy company has been fined after a worker’s toe was crushed by an unguarded part of a yoghurt filling machine.

Machine guarding incident results in amputation

Worker suffered a spiral fracture and an open wound to his left upper arm. Surgery to restore the blood supply to his arm was unsuccessful resulting in amputation of the arm.

Unmaintained machine guards: Firm fined for repeated safety breaches

Employees had been exposed to the risk of serious injury because their radial arm drill was not fitted with an effective telescopic guard or trip device.

Fine after machinery guarding failure leads to partial amputation of a finger

An agency worker at a haulage and waste processing business had his hand drawn into an in running nip on a waste sorting conveyor, while trying to clear a blockage beneath the belt.

Fingers amputated after machine entanglement

HSE: “This injury was easily preventable and the risk should have been identified. Employers should make sure they properly assess and apply effective control measures to minimise the risk from dangerous parts of machinery.”

Pirelli Tyres safety breach: Company fined after same machine breaks two worker’s arms

The HSE’s investigation found the machine, which was manufactured by Pirelli in 2003, was not properly guarded, despite the first incident.

£200k fine after worker loses arm

A Yorkshire transportation and storage company has been sentenced for safety breaches after a worker suffered injuries leading to the loss of his left arm.

Manufacturer fined for worker’s burn injuries

An employee’s hand became trapped in a sanding machine, causing burn injuries that needed surgery.

Fine after worker is covered in chemicals

An Essex based chemical company has been sentenced after an employee was injured when a storage tank failed.

£120k fine following severed finger incident at toilet roll firm

A 22-year-old man had part of his finger severed whilst working at a toilet roll manufacturing company in Blackburn.

Lancashire bakery fined after worker pulled into mixing machine

A 32-year-old baker was seriously injured when he became trapped in a food-mixing machine at a Lancashire bakery.

£20k fine after worker’s hand amputated

A manufacturing company has been fined after a worker’s hands got trapped in a 25 tonne press.

Worker’s hand crushed in machinery

A food seasoning manufacturer has been fined after an agency worker suffered serious hand injuries when his finger got caught in a machine.

£300k fine after dangerous machinery incident

Devonshire based textile company has been fined after a 21-year old employee suffered life changing hand injuries.

Joinery firm gets £230k fine following serious hand injury

Avon Joinery received a £230k fine after finger of employee was severed.

Unsecured machinery crushed worker’s foot

Lancashire based Spectral Colours Limited (SCL) has been fined after a worker was crushed under machinery.

Bakery company fined for safety failings

A bakery company based in Hertfordshire has been fined for safety failings. Stevenage Magistrates’ Court heard how Arnaouti Pitta Bread

Firm fined £140k after worker suffers fourth degree burns

Manchester aluminium diecasting producer Presbar Diecastings Ltd, has been fined £140,000 after a worker suffered life threatening injuries when he became trapped in

£815k in fines after worker is fatally crushed

Two companies were fined a total of £815,000 after a worker and father-to-be was crushed to death in Lancashire by

Worker injured with powered bowl mixer

A Wiltshire bakery has been fined for safety failings after a worker was injured with a powered bowl mixer. Swindon

Fine after woman injured at crystal manufacturer

A Cumbrian lead crystal manufacturer has been fined after an employee suffered a serious hand injury while using machinery. The

Swansea company in court following worker’s injury

A Swansea company which manufactures plastic sheeting has been fined after an employee suffered serious injury when his hand was

Company had inadequate assessment for processing hemp

A Welsh insulation company that produced natural insulation products has been fined for health and safety failings. Wrexham Magistrates’ Court

Download: October 2020 Legislation Update

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    • Latest COVID-19 measures and legislation;
    • Fire safety and post-Grenfell safety regime;
    • Brexit;
    • Environment legislation updates;
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    • And much more...
April 2020 Legislation eBook

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