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This guideline is aimed at employers, engineers, designers, manufacturers and distributors of machinery. WorkSafe has also developed a set of fact sheets for specific machinery. Though relevant to employers, these fact sheets are mostly aimed at operators and employees.
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Safe use of machinery
While this guidance has not been updated to reflect current work health and safety legislation (the Health and Safety at Work Act and regulations), it may still contain relevant information and practices to keep workers and others healthy and safe.
Please read this guidance in conjunction with all relevant industry standards that apply to you as a PCBU. This guidance will be progressively reviewed and either updated, replaced with other guidance, or revoked.
The Best Practice Guidelines for the Safe Use of Machinery outlines the hazards that come with using machinery in the workplace, potential injuries and how best to control these hazards. It gives duty holders advice on how to use machinery safely and meet their duties under the Health and Safety in Employment Act (HSE Act) and the Health and Safety in Regulations (HSE Regulations). When using this guideline, consider the unique demands of your workplace and industry; there may be other hazards and risks not covered in this guideline.
The HSE Act and HSE Regulations place responsibilities on many different persons, including machinery and plant designers, manufacturers, suppliers, installers and operators, employers and owners of machinery. These people are called 'duty holders'. Duty holders must take all practicable steps to make sure machinery in the workplace is designed safely and is adequately guarded to reduce the risk of injuries or harm.
Machinery can injure people by:
Common injuries include:
WorkSafe New Zealand has identified a number of trends where employers have been prosecuted for injuries and fatalities to staff and contractors through using machinery. These trends are:
Duty holders should use the Australian Standard AS Safety of machinery series as the standard that gives the current state of knowledge for the safeguarding of machinery and plant. It should be referred to by duty holders as the primary standard against which to benchmark. Employers, suppliers, manufacturers and designers can work to other standards, but they need to show that they can reach the same level of safety, or better, in the circumstances in which they are used.
Employers must make sure anyone they engage for advice on machine guarding and safety is a competent person and is experienced at working with and using AS or equivalent or higher standards.
Based on key information from AS , this guideline advises employers and other duty holders on managing machinery hazards. This guideline is the key reference for what safety looks like when using machinery.
This guideline is part of a suite of guidance for the use of machinery. For further information refer to WorkSafe's Safe Use of Machinery.
This guideline has a series of flowcharts that cover the key concepts around machinery safety. The flowcharts work through the processes for commissioning, manufacturing or purchasing machinery and how hazards can be eliminated at this point.
The design stage is the best time to control the hazards associated with machinery. Whether commissioning or designing a new machine, or changing an existing machine ' this is the chance to get rid of significant hazards. WorkSafe recommends eliminating hazards at the start of the commissioning or purchase process.
The flowcharts also cover identifying hazards, risk assessments, choosing appropriate guarding and how to develop a safe system of work. The aim is to create a safe working environment and safe systems of work for anyone working with or near machinery.
Use the individual flowcharts to scope the design or to modify of a piece of machinery. The key is identifying and assessing all hazards caused by the machine and its use, which then must be eliminated, isolated or minimised.
If you cannot eliminate or isolate them, work through the hierarchy of guarding options (see section 5 of this guideline) before moving to minimising the hazard.
Minimisation includes:
The flowcharts are collated together in section 11.6 and also appear in the appropriate section of this guideline.
Flowchart 1: Get it right from the start ' overview of safe use of machinery guidelineDesigners, manufacturers, suppliers and employers all have responsibilities to ensure machinery is safe to use. Figure 1 shows who has health and safety responsibilities for each phase or aspect of the machine's life cycle.
Figure 1: Division of health and safety responsibilities during a machine's life cycleThe best time to make machinery safe is at the design stage. Designers of machinery must take all practical steps to ensure that what they design does not become a hazard to anyone building, installing, using, maintaining or repairing it.
Designers, manufacturers and suppliers of machinery and personal protective equipment have legal duties; these are explained in HSE Regulations 66 to 69.
Equipment designs should meet relevant New Zealand and international standards.
Figure 2 summarises the designer's responsibilities which are to ensure machinery:
Designers should provide thorough and easy-to-understand information and instructions to the manufacturer about how to build the machine so it meets the design criteria. The designer also needs to give information on the right way to install, operate, adjust, maintain and repair the machine.
Manufacturers and suppliers of machinery should take all practicable steps to make sure it is designed, manufactured and tested so it will not harm anyone during:
Manufacturers and suppliers are responsible for:
HSE Regulations 67 describes the duties of manufacturers and suppliers of plant.
Under section 18A of the HSE Act, a person who hires, leases, sells or otherwise supplies another person with a machine to be used in a workplace has legal duties.
People who hire, lease or loan machinery must find out whether it will to be used in a workplace, and if so, how it will be used. They must ensure that the machinery has been designed, made and maintained to be safe for its intended use.
People who sell or supply machinery that can be used in a workplace must take all practicable steps to make sure it has been designed, made and maintained to be safe for any known intended use or any reasonably expected use. If a seller or supplier agrees to install or arrange a machine, section 18A(3) of the HSE Act says they must take all practical steps to install or arrange the machine so it is safe for its intended use.
Health and safety legislation requires people to make sure others are safe at work. It also protects people using machinery and equipment.
Manufacturers and suppliers must give thorough and easy-to-understand instructions on how to use the machine safely (see HSE Regulations 67(3) & (4)). People who make and supply protective clothing and equipment have similar duties (see HSE Regulations 69(4) & (5)).
Any instructions must explain:
The supplier, or the purchaser or hirer, must understand and follow the information.
Machinery that is designed from the outset to remove hazards should reduce costs for employers due to less need to:
For more information, see WorkSafe's Position Paper for the Safe Use of Machinery.
Exceptions to section 18(A) of the HSE Act are goods that are second-hand or sold 'as is'. 'As is' means without promises or warranties as to quality, durability or fitness, with the buyer carrying all risks. Buyer beware!
The installer must thoroughly identify and assess all hazards and determine the machine's limits using the latest AS .1, or other equivalent standard.
An engineer must decide what safety category the machine falls into and what guards it needs so it meets AS . The engineer needs relevant experience and knowledge of machine guarding and the requirements of AS .
The manufacturer must validate that the design of all safety features in control components and control systems meet the standards of sections and of AS . If the manufacturer cannot do this, an engineer (with relevant experience and knowledge) must inspect the machine and validate that it meets AS .
The machinery must be installed according to the manufacturer's instructions. If the person selling or supplying machinery agrees to install it, the law says they must take all practicable steps to install or arrange the machinery so it is safe for its intended use (HSE Act section 18A(3)).
Employers are responsible for the health and safety of their employees and any other people who can be harmed by the actions or inactions of their employees. Employers must, as far as practicable:
If an employer can only minimise a hazard, they must monitor the environment and the health of employees.
The employer or person in control of the workplace must not let anyone use a machine unless they have had training on:
Employees must be supervised and trained by a competent person (section 13 HSE Act).
When training people to use machinery, a trainer must explain:
Take manufacturer's instructions into consideration when developing training programmes for operators.
Employers must take all practicable steps to stop anyone under the age of 15 years old working or helping with work with machinery.
No one under the age of 15 years old should be in an area where:
Unless they are:
Minimum ages in health and safety legislation:
The employer or principal must have an inspection and maintenance programme in place. This programme must ensure a competent person regularly inspects, tests and maintains the machine's guards and safety control system. This ensures the safety system's reliability and integrity.
When developing maintenance and repair programmes, refer to the manufacturer's instructions.
Maintenance and repair programmes should specify:
Programmes should be reviewed regularly to ensure their effectiveness. Develop, implement and maintain an accurate record of maintenance done and maintenance programmes.
Employers should take all practicable steps to make sure any hazardous machinery has stopped before any cleaning or maintenance is done. HSE Regulation 17 requires employers to make sure machinery is safe to clean, maintain and repair. Procedures must be put in place for these activities to be performed safely and workers must be trained to follow them.
Isolation, tag out cards and lock-out devices should also be used as described in section 8.1.11 of this guideline.
Any other hazard present should also have the appropriate control applied to stop people being harmed.
If it is essential for the cleaning, maintenance or repair procedure that the machine stays in operation, then employers should:
Mid-position pendants are better than jogging or inching machinery using a hold-to-run control. The machine should run at the slowest practical operating speed for cleaning, loading and setting up. The inching control should be a hold-to-run type, so the machine stops immediately when the control is released.
Employers should maintain and keep machinery in sound operating condition at all times. They can manage the maintenance using:
The manufacturer's and designer's instructions should be referred to before modifying any plant.
Modifications should be only be completed by a competent person who has knowledge and experience of AS and the type of machine or plant.
Any modifications must be validated so the design of all safety features in control components and control systems meet the standards of sections and of AS . If the manufacturer cannot do this, an engineer (with relevant experience and knowledge) must inspect the machine and validate that it meets AS .
Any decommissioning and dismantling of machinery must be undertaken as per the manufacturer's instructions and completed by a competent person.
When using machinery an employee is responsible for:
Machine operators should:
Where there is a risk of entanglement with machinery, people should:
Employees are often in the best place to know the hazards of their job and how they could be injured. For example, product might back up in the machine and need clearing, which could be hazardous if the machine is still running.
Everyone benefits when employees are involved in developing health and safety systems, and when those systems are part of the daily life in the workplace.
The HSE Act gives employees the right to participate in health and safety issues at work and gives them access to information and training.
Employees may elect a health and safety representative for their workplace. The health and safety representative is someone that staff can go to and discuss any problems around health and safety. The health and safety representative will work with the employer to find a solution.
In larger workplaces, employees' representatives may be elected onto the health and safety committee that also includes representatives of the employer. Where employee health and safety representatives are elected, they are entitled to paid leave to attend approved training courses.
If an employee has genuine concerns about health and safety, they have the right to refuse unsafe work (HSE Act section 28A). This should only happen when other avenues to deal with the problem have not been successful. During the time the employee's concerns are being investigated, he or she may need to perform other duties in the workplace.
For more information see WorkSafe's fact sheets:
Making sure hazards do not cause harm or injury is the basis of health and safety in any workplace. This section covers the basics of hazard management and the common hazards that are found when working with or near machinery.
Planning a safe approach to a job can help identify the hazards of working with machinery. The hazard management process includes:
The first step in the hazard management process is to identify hazards ' anything that could injure or harm someone.
Do a workplace inspection to identify all machinery used. Include common items that may not normally be thought of as 'machines'. Also consider how other workplace items such as chairs and heaters can affect the use of machinery.
Sections 7'10 of the HSE Act outline the process to identify, assess and control hazards.
Once you have identified all machinery, you can identify their hazards.
A good hazard identification process is key to hazard management. You can identify hazards using:
Hazard and operability analysis (HAZOP).
Hazard identification and management should be completed and monitored regularly to make sure control measures are working and no new hazards have been introduced. See Appendix 1 for a sample hazard checklist.
Figure 3: Processes are used together to identify hazardsCritically inspect each piece of machinery and how it is used to identify where someone could be harmed by:
For more information see:
In this guideline hazards are split into two categories: machanical hazards and operational hazards. This section covers the main hazards caused by the machinery itself.
Many pieces of machinery use force and motion to cut, bend, join or shape materials. This force and motion can harm people. Some of the ways people can be hurt are covered in this section.
Machines and machinery parts in the figures section are unguarded to show the hazards and danger zones. Flowchart 2 shows the most common types of machinery hazards.
Prime movers are devices that turn energy into motion to power a machine. Prime movers include:
Every flywheel directly connected to a prime mover and every moving part of a prime mover should be securely guarded, unless it is safe because of its position or construction. It must be safe for everyone in the workplace. Prime movers also include motors powered by burning solid, liquid, or gas fuels such as coal, petrol or natural gas.
Flowchart 2: Common machinery hazardsTransmission machinery takes energy from a prime mover to the part of a machine where it is used. Every part of any transmission machinery should be securely fenced unless, because of its position or construction, it is safe. Figure 4 shows some ways operators can be injured by this type of machinery.
Transmission machinery can include gears, shafts, pulleys and belts, chains and sprockets, or friction drives.
All transmission machinery should have a device in every room or workplace to cut the power to the machinery.
Solid red arrows = where a part of the body could be drawn into a nip-point
White or grey arrows = movement of machine parts
Injuries can be caused when a part of the body is drawn into a 'nip-point'. Figure 5 shows some ways operators can be injured by drawing in and trapping hazards, such as:
Figure 6 shows some ways operators can be injured through crushing hazards that can happen when part of the body is caught:
Impact hazards are caused by objects that strike the body, but do not enter it.
Figure 7 shows some ways operators can be injured by impact hazards. Examples include the rotating arm of a robot, the reciprocating bed of a metal planing machine and the arms of a wool-scouring machine.
Impact hazards are different from crush hazards even though the machines involved may be the same. Impact hazards involve the inertia of the body while crush hazards involve trapping the body between two machine parts or between a machine part and a fixed structure.
Figure 7: Examples of impact hazardsFriction burns can be caused by smooth parts operating at high speed. Figure 8 shows some ways operators can be injured by friction and abrasion hazards. Examples of friction or abrasion hazards include:
Entanglement is when someone is caught in a machine by loose items (such as clothing, gloves, ties, jewellery, long hair, cleaning rags, bandages or rough material being fed into the machine).
Figures 9, 10 and 11 show some ways operators can be injured by entanglement with machinery. Contact that can lead to entanglement includes:
Shearing trims or shears metal (or other material) with a powered knife or slide. Shear points are found where stock is inserted, held and withdrawn. Figures 12 and 13 show some ways operators can be injured by shearing hazards.
Parts of the human body can be sheared:
Cutting hazards exist at the point where wood, metal or other materials are cut. Figure 14 shows some ways operators can be injured by shearing hazards.
Many kinds of tools create cutting hazards:
Cutting hazards may involve rotating, reciprocating or sideways motion. Danger exists at the cutting point, where a finger, arm or body part can be injured. Flying chips or scrap material can strike the head, particularly in the eyes or face. The danger is worse if the person caught cannot move away from the cutter.
Figure 14: Examples of cutting hazardsThe human body can be pierced by flying objects. Figure 15 shows some ways operators can be injured by stabbing and puncturing hazards. For example:
The human body can also be pierced by rapidly moving parts of machinery or pieces of material. For example:
Injection of fluids through the skin can cause tissue damage similar to stabbing.
Figure 15: Examples of stabbing and puncture hazards by flying objects or moving parts of machineryErgonomic hazards come about through the way the operator interacts with the machine. Sometimes machinery is not always designed for how an operator must use the machine. For example, operators may have to overreach, reach above shoulder height, hold awkward postures, and use repetitive or forceful movements. Having to work this way can cause damage to nerves, muscles and tendons.
Ergonomic hazards can cause serious harm to operators, but they do not need to. These hazards can be removed at the design stage.
By considering how and when a machine is used, you can reduce the risk of injury. This includes:
Check whether tasks require repetitive movement or there is a risk of musculoskeletal injuries and gradual process disease.
More information can be found in WorkSafe's Code of Practice for Manual Handling.
Good layout makes any guarding better at keeping people safe. Machines that are poorly placed or too close together can be unsafe, even if guarded.
When designing layout:
Check how close moving parts are to other machinery and fixtures in buildings.
The main point of machine guarding is to stop workers reaching past the guard into the machine. When deciding on the best way to guard a machine, consider how a worker uses and interacts with a machine (ergonomic principles).
More information on ergonomics is in section 7.2 of this guideline.
Many chemicals used with machinery can harm workers. Assess all chemicals for hazardous health effects. Put appropriate controls in place to stop or control people's exposure. In some cases, you may need to monitor the environment or workers' health to make sure exposure to the chemicals is not affecting their health.
For more information refer to the substance's safety data sheet, available from your supplier.
Protect workers at all times from inhaling steam, fumes, dust and other airborne contaminants in the workplace. You can use ventilation, filtration and/or mechanical extraction. Remove any contaminants made as part of the work at the source.
Any mechanical extraction must pull contaminants away from workers' breathing zone, not through it.
If it is not practical to completely remove or isolate the hazardous substance, you must minimise any risk of harm to the employee.
To minimise a hazard's effects, an employer can:
For machine guarding to work well, employers must:
New technology, new machinery or changes to machinery can introduce new hazards. At these times, always complete a hazard assessment and consult with workers.
Employers must take measures to prevent fatigue causing harm, such as when employees must drive or use dangerous machinery. Employers are not responsible for anything outside work that reduces an employee's ability to cope or leads to fatigue. But they must have systems to identify and deal with such factors when they can affect workplace safety.
Shift-work can be hazardous because it disrupts normal rest patterns. Employees need enough recovery time outside work so they can be safe and productive at work.
Along with enough sleep, breaks during work hours are important to maintain an employee's physical and mental well-being. See WorkSafe's Stress and Fatigue: Reducing Their Impact ' Advice for Employers and Employees guide for more information.
The wiring and fittings of machinery connected to the mains (or similar) must meet all legal requirements and must be installed by a registered electrician.
A certified, professional third party must do all tagging and testing in line with electrical regulations.
All portable or handheld machinery that gets power from electricity should be used with an isolating transformer or residual current device, where needed. Get specific advice from the electricity supplier on the best device to use.
When reviewing machinery for non-mechanical hazards, consider how machinery can affect the area around it.
A thorough hazard identification process needs to consider the effect environmental factors (such as lighting, heat, and cold) have on workers when using machinery.
People need a suitable work platform to reduce the risk of falling from machinery.
Working safely at height may need:
For more information, see WorkSafe's Best Practice Guidelines for Working at Height in New Zealand.
Make sure the work area is well lit. Poor lighting can be a hazard. Sometimes the machine or guards can block normal lighting so extra local light is needed. Also put local lighting in regular maintenance areas that are poorly lit, such as inside some electrical compartments where electrical isolation is needed for access.
For more information refer to AS/NZS .2.4 Interior lighting ' Part 24: Industrial tasks and processes.
Employers must take all practicable steps to reduce any risk of harm to people from machinery noise. Machinery noise should be eliminated, or through isolation kept to a level that does not damage hearing.
Where this is not practical, employers should isolate people from excessive noise.
Where neither option is practical, employers must put systems in place to make sure people exposed to the noise are unlikely to suffer harm.
For more information on controlling noise, refer to WorkSafe's Approved Code of Practice for the Management of Noise in the Workplace.
Noise limits for an 8-hour day, peak noise levels and protective measures are in HSE Regulation 11.
No machine should be driven or used at an unsafe speed. Where a designer or manufacturer recommends a working speed for a machine, do not go any faster.
Maintain machines so there is no dangerous vibration when the machine is working or when moving parts and cutters are run at idle or full speed.
All machinery must be secured to the floor or other structure so that it cannot tip, become unstable or create any other hazards, unless it is designed to be portable.
Large machinery may need a lot of guarding, which needs to be removed for maintenance access. Design guards to come off easily and be handled by one person. Well-placed handles make removing, lifting and handling easier and reduce the risk of manual handling injuries.
Where practical, use cranes or other lifting devices to move heavy guards.
Operators and employees need safe access into, on and around machinery. Workers need a stable work platform that is right for the work they need to do. The operator should be able to keep good posture while working. The platform must give a sure footing, a safe working environment and prevents falls it is at height.
When designing safe access to machinery, think about who, what, where, when and how.
Larger machinery and equipment can have enclosed areas that are difficult to get to. In confined spaces, oxygen levels may be low or there may be harmful levels of gas, vapour or dust.
Flowchart 3: Identify operational hazards to use machinery safelyFor more information, refer to the Australian Standard AS Confined spaces.
Mess can cause slips, trips and falls. Avoid injuries by:
Design machinery and work processes to minimise oil loss or spillage. Clean up spills as soon as possible and avoid any oily residues on the floor. Provide a rough anti-slip floor where this is not practical.
Flowchart 3 shows the more common hazards associated with machine operations. Apart from the hazards associated with the normal running of the machine, the flowchart also covers hazards associated with cleaning, maintenance and repair, along with irregular hazards.
To keep people safe during inspections, cleaning, repairs, maintenance and emergencies:
HSE Regulation 17 requires employers must make sure machinery is safe to clean, maintain and repair. Procedures must be put in place for these activities and workers trained to follow them.
Hazard and risk assessment is a process to determine how significant a hazard is and what harm it could cause.
Flowchart 4: Assess hazard and risks ' eliminate hazards where possibleEvery identified hazard must be assessed to see if it is a significant hazard ' something that could cause serious harm. If it is a significant hazard, it must be controlled using the hierarchy of controls. A significant hazard should be eliminated, if it can't then isolated, and if that isn't practicable, controls should be put in place to minimise the hazard. If it is not a significant hazard the employer must still take all practicable steps to ensure the equipment is safe for employees to use.
Use flowchart 4 to work through the hazard and risk assessment process. This is the process to assess hazards, select controls and to assess whether these methods have reduced or eliminated the risk of harm occurring.
To manage risks effectively, an assessment of how likely a hazard is to cause harm must occur and, if it does, how badly someone can be hurt. This helps prioritise which hazards need to be dealt with first.
Any risk assessment should cover:
For example, with hazards from moving, rotating or reciprocating machinery, first assess how likely it is that a worker could get caught, entangled or nipped, and then determine how serious any injury might be.
Risk factors to consider during the risk assessment include:
When assessing the risk, take into consideration:
Solid red arrows = where a part of the body could be drawn into a nip-point
Grey arrows = movement of machine parts
Risk assessment is not an absolute science ' it is a 'best estimate' made on the basis of available information. As such, the people doing risk assessments need the right information, knowledge and experience of the work environment and work processes. They need to talk to workers and health and safety representatives, who can advise on the particular hazards and risks for different machinery.
The AS Safety of machinery series has more information on risk assessment factors and methodology ' see AS . and AS . in particular.
Figure 17: Risk assessment explains one process for assessing risks and hazards Figure 18: A example risk rating tableEmployers and principals are responsible for making sure the hazards associated with machinery are controlled in the workplace so they do not harm workers and operators.
Sections 8-10 of the HSE Act outline a hierarchy of controls that must be used when a significant hazard has been identified. The hierarchy consists of three steps: eliminate, isolate or minimise the hazard. If employers cannot eliminate or isolate the hazard (because it is not practicable to do so) they must minimise it.
With elimination, the hazard or hazardous work practice is removed from the workplace. With machinery, this may involve employers changing processes and machinery so workers are not exposed to significant hazards. Hazards can be eliminated at the design stage too (see section 6 of this guideline).
If elimination is not practicable, the significant hazard must be isolated. This involves isolating or separating the hazard or hazardous work practice from those who may be harmed by it. These usually protect everyone around the machine (which is known as a group control). They can be fixed guards, interlocked guards or safe by position.
If it is not practicable to eliminate or isolate the hazard, then the likelihood of it causing harm must be minimised. Minimisation provides a framework of expected behaviours, such as rotation of staff to reduce exposure to a hazard, personal protective equipment or a documented safe system of work ' such as 'lock-out ' tag-out'. These types of controls rely on extensive instruction, information, training and supervision.
Minimising a hazard can stop injuries, but it is the least effective option because it relies more on human behaviour, maintenance programmes and supervision. In the long term, minimisation can also be more expensive, because it needs time and ongoing oversight by managers and employers, and additional costs of personal protection (eg hearing protection).
When a hazard can only be minimised, section 10 of the HSE Act requires employers to monitor employees' exposure to the hazard and monitor their health. Employers can only monitor employee's health with their informed consent.
Because minimisation relies on human behaviour, hazard management needs to consider the actions of the people who:
With changes in technology and cost of solutions over time, measures to eliminate and/or isolate a hazard may become practicable. Duty holders should continue to assess significant hazards that are being minimised in order to determine whether there are other methods to control them. For example, replace with a newer machine that eliminates or isolates the hazard.
Duty holders should use the AS Safety of Machinery series as the standard that gives the current state of knowledge in relation to safeguarding machinery and plant. It should be referred to by duty holders as the primary standard against which to benchmark. Employers, suppliers, manufacturers and designers can work to other standards, but they need to show that they can reach the same level, or better, of safety in the circumstances in which they are used.
The level of familiarity with AS will depend on the responsibilities of the duty holder. For instance, when buying new machinery or hiring machinery, the employer must make sure any machinery purchased or hired meets AS , or equivalent or higher standards.
The employer must make sure that any competent person they hire to give advice or services on machine guarding or safe use of machinery is experienced in using AS , or equivalent or higher standards.
However, an engineer maintaining and repairing machinery and/or installing guarding should be very familiar and experienced with AS and be able to readily access a copy.
See Section 11.4 for a summary of the AS Safety of Machinery series.
Table 1 covers options for eliminating hazards, the types of guards and methods that isolate workers from hazards, and examples of how hazards can be minimised. The controls are split into two categories, individual and group controls. Group controls protect more than one person, whereas individual controls can only protect one person at a time.
If hazards can't be eliminated, there are a number of options to isolate operators from machinery. When deciding which guarding methods to use, consider practicality and how the operator will use the machine. Many factors determine the choice of guard. Depending on the situation, a combination of two or more guards may be needed to keep workers safe.
Table 1: Matrix of guarding controlsThe best time to eliminate hazards is at the machinery design stage. This section covers some of the common hazards that can be eliminated through design. The section also outlines the principles of including health and safety in the design process.
The design process usually begins with:
At this point, the designer should get advice from safety experts, people who might use it and engineers to help design a safe machine. Machinery must be designed that does not hurt anyone at any point in the process of its manufacture, installation, use, maintenance or repair.
Designers must consider how the machinery can injure people working with it. Injuries include:
Common hazards that can be eliminated through design include:
Experience shows that protective measures built into the design are more likely to stay effective even when well-designed safeguarding fails, an error is made or safety procedures are not followed.
Hazard identification is the first step in the design process. Examples of safe design that eliminates particular hazards rather than relying on safeguards to prevent harm include:
Avoid creating hazards by considering:
Find more information on inherently safe design in AS . Safety of machinery: Part : General Principles ' Technical Principles.
When designing the machine's stability, consider:
The designer must develop technical information for the supplier and buyer from standards, codes and calculations. The information should cover:
The designer must consider:
The designs of safety-related parts of control systems need to be validated by a competent person. Validation confirms that all steps of the safety life cycle were implemented and verified.
Designers can find information on reducing safety system failure through good design and typical failure modes in AS . Safety of Machinery: Part : Design of Safety Related Parts of Control Systems ' Validation.
Different hazards exist at different stages of a machine's life cycle; many of these can be reduced or removed through thoughtful design.
The making of machinery is the first phase of the life cycle. Examples of removing or controlling hazards include:
HSE Regulation 66 describes the duties of designers of plant.
Moving the machine to where it will be installed is the next important step.
An example of removing a transport hazard is a metal lathe is to be delivered fully assembled and is much heavier at one end. The designer notes the chance for the lathe to slip out of its lifting slings, so they incorporate lifting eyes for the slings in positions that mean the lathe can be lifted in a horizontal position.
Once a machine is safely delivered, it needs to be installed.
For example, to reduce hazards during installation, design a large machine to be delivered in modules that are put in place by a crane. Then installers do not need to work at height or handle heavy items by hand.
The designer can build in test points for instruments and alarms so a machine or parts of machinery cannot be energised by mistake.
Designers must design machinery and plant that is safe to use. Some examples of designing machinery for safe operation:
Manufacturers and designers should make sure machinery can be stored without creating hazards or when started after inactivity. They can include information on how to break down the machine for safe storage.
People breaking down machines for scrap can face significant hazards. These include:
The concept stage of a project is the best time to get things right. With thorough research, planning and consultation, many hazards can be eliminated before a machine is designed, purchased, installed or modified.
Once the need for new machinery or a change to existing machinery is identified, adding health and safety into the business case will help to assess hazards and risks. This can also help avoid budget blow outs, unpleasant surprises and costly retrofitting.
A thorough business plan includes at least the following elements outlined in sections 6.4.2 to 6.4.7 of this guideline.
A return on investment (ROI) assessment should incorporate health and safety implications. For example, two different machines can get the same results. One machine costs $10,000 more but is insulated and does not make enough noise to damage hearing. If the cheaper machine was purchased, the company would have to spend $15,000 on hearing protection and hearing monitoring for operators.
The machine that is $10,000 more expensive will actually save the company $ in safety equipment and health checks.
Some businesses incorporate health and safety costs in the CAPEX sign-off process. A senior manager responsible for health and safety ensures an assessment is done and any risks addressed before the machine is purchased.
Anyone buying or modifying machinery to be used in a place of work has legal duties. The person putting together the business case should check what laws apply to their business. All businesses must comply with the HSE Act and the HSE Regulations.
The business case should address health and safety and consider the following:
By doing a detailed hazard identification process before starting, hazards can be eliminated at the design stage. Use Flowcharts 2 and 3 to identify the most common machinery hazards.
While removing hazards is the best option, not all hazards can be eliminated. If hazards cannot be eliminated, consider how they can be isolated. Flowchart 7 can help choose the right guarding solution.
If guarding is not possible, hazards must be minimised. Flowchart 8 covers the minimum requirements for a safe system of work.
Once the business case is accepted, a project plan is usually developed. Health and safety implications and information about hazard management should be included in the project plan.
All machinery should be soundly built. Machinery should also be built so it is free from dangerous vibrations when in use. This includes any cutter fitted to a machine running at full speed or at idle.
In the flowchart 6, the left hand column specifies steps in the process of ensuring the safety of a machine. The right column lists procedures carried out to test and ensure the safety of a machine.
Safety validation is a documented examination of the machine and its processes. The examination must be done to national or international guidelines or standards. The examination compares the actual status of the machine or work with what it should be.
Anyone doing a validation needs extensive knowledge of the equipment and how it should work. The person must be competent to compare the machine's safety features and performance to the planned results established by the safety requirement specifications and risk assessment.
Flowchart 6: Validation and verificationValidation verifies that the safety design was put in place correctly and checks that the machine works safely and meets the safety requirement specifications. Depending on the machine, validation can include:
The following are some recommended steps to take to complete the validation process.
This is done by the person in charge of the validation once the risk reduction methods have been put in place on the machine. It should include descriptions of how the machine was made safe to operate and any minor hazards remaining should be noted. If new hazards have appeared as a result of any modifications, these must be noted and controlled.
Validation must also check the design of controls and how the software functions.
This can include:
Each safety feature is individually tested and validated; for example, each emergency stop is pressed and what happens is compared to what the safety requirement specifications say is supposed to happen.
Assess the machinery for other hazards. Flowcharts 2 and 3 can help in this assessment.
This section covers the types of machine guarding available and the situations where it is generally used. Depending on the situation, a combination of two or more safeguards may be needed to keep workers safe.
Fixed guards are physical barriers that keep people out of dangerous areas during normal use, maintenance or cleaning. The need to adjust drive belts and transmission chains, other machinery parts, can affect guard design.
Fixed guards can be:
permanent
' welded into or part of the body of the machineremovable
' but they can only be removed when the machine is stopped with a special tool that is not easily available to operators. Do not use wing nuts, wedge inserts or anything that can be undone with the fingers.Barriers or fences held securely in place with fasteners or other suitable devices can stop access to dangerous areas.
Machine guards should be made of substantial materials (such as sheet steel, wire mesh) that cannot be easily damaged.
Figure 19: Example of a fixed guardInterlocked guards work by cutting power to the machine when the guard is opened. They are a good guard to use when a machine needs to be accessed often.
If parts keep moving when the machine is not working, you must use a type of guard that cannot be opened until all parts have stopped moving, or fit devices that stop the machinery. Any brakes fitted to machinery must be well maintained.
Use a suitable anti-free fall device with interlocked rise and fall guards on machine tools that can injure if they free fall under gravity.
Power-operated guards should work with a minimum of force so they do not create a trapping hazard. Where it is not possible to reduce the closing force of a guard, fit a safety trip device to the leading edge of the guard that will stop and reverse the guard if it contacts an object, like a hand.
With barriers like fences, there is a danger that machines can start when someone is close to them, such as when an interlocked door accidentally closes and the machine re-starts. To avoid this hazard, fit devices to stop an interlock door or gate closing accidentally (such as a spring or gravity latch, which need a deliberate action from someone to close the door).
Interlocked guards must be designed so that any failure or loss of power does not expose people to danger. The design also needs to consider the possibility of someone being inside the area enclosed by the guard when someone tries to start the machine.
Only after doing a risk assessment can you know what type of safety device to install with the guard, and the level of integrity of the related control circuitry. If needed, more information is available in AS . Safety of Machinery: Part : Design of Safety Related Parts of Control Systems ' General Principles for Design.
Figure 20: Perimeter fence guard with fixed panels and interlocking access door Figure 21: Food mixer with an interlocking guardThis method of hazard management relies on putting dangerous machinery parts out of reach of people. The problem with this method is that people can often use ladders, furniture or machine parts to reach the hazard. This method needs policies and practices in place to make sure that the protection is not compromised.
When deciding how far away to put dangerous machinery, also consider how maintenance people will get access, such as by ladder, scaffold or mobile elevating work platform.
When other guarding methods are not practical, you can use trip guards. A trip guard is designed to cut the power if someone reaches into a dangerous part of a machine.
However, if this system fails, there is no physical barrier to stop people touching dangerous parts. All safety trip guards should be hardwired to the machine control and power brake systems.
Ergonomic principles cover how a worker uses and works with a machine. Making sure workers cannot reach past the guarding into the machine is a key part of machine guarding and isolating the people from hazards.
Typical ergonomic principles include:
Part of body
Gap (maximum size of any aperture or openings in the machinery)
Minimum separation distance from danger zone
If you are looking for more details, kindly visit surgical three-edged pins.
Fingertip
4 mm
2 mm
Finger
6 mm
20 mm
Arm
20 mm
850 mm
Arm (reaching above head)
2,700 mm
Table 2: Separation distances and gaps
Reach is limited by the length of arms, fingers and hands, legs and feet. The distance a person can reach sets the minimum height for some guards or the minimum distance of barriers from the hazard.
The average size and reach of humans is used to set design criteria. There will be some people ' the very tall or very slender ' whose size means they are not fully protected by the standard measurements given. Protect these people using the more restricted measurements in the following publications:
Use Table 2 above to assess the risk in equipment and the design and positioning of guards. The minimum separation distances are based on people with long arms, hands and fingers. The gaps are based on people (over 14 years old) with small fingers and hands.
The separation values are more conservative than values calculated from the Ergonomics of Machine Guarding Guide. Where needed, more information is in AS . Safety of Machinery: Part : Safety Distances to Prevent Danger Zones Being Reached by the Upper Limbs.
The anthropometric data used in this standard was based on information available when the standard was developed. Better sources may become available. If your workforce is significantly different from the general population, you may need to take your own measurements.
If someone can fit an arm through a gap, the hazard assessment should also consider any smaller openings inside the machinery.
If the arm can be bent at:
Distance guards should be at least mm tall and at least 900 mm away from the danger zone; further or higher if there is a projectile hazard.
If the guard is between mm and mm tall, it must be at least mm away from the danger zone. No guards should be less than mm high.
This section details the type of guarding and control options that will only minimise the likelihood of harm occurring. These controls should only be used if the hazard cannot be eliminated or isolated.
These guarding options generally protect more than one person and are called group controls. Pictures in this section show guards in yellow and emergency stop buttons in red.
The power control is the device on a machine that controls the flow of energy to the prime mover. This energy may be:
The power control should be able to stop the flow from all energy sources. Interlocks and labels should clearly indicate where there is more than one energy source and stop all sources of energy to the prime movers.
HSE Regulation 66 requires that plant and power control placement are designed with ergonomic principles.
The power controls should be:
Hydraulic controls should be either dead-man or hold-to-run type with anti-tie down, so that if the control is released the machine stops moving.
When a machine's power falls to a low level or stops completely, exposing parts of the machine, this can create a significant hazard when the power is restored. The machine should need the deliberate operation of the power control to start the dangerous parts.
If the machine operator cannot see the whole machine, a warning device must alert people either visually, by sound or both before the machine restarts.
Photoelectric safety devices use light beams that stop machines working when the light beam is broken. This method is often used when fixed or interlocked mechanical guards are not practical. However, if the system fails, there is no physical barrier to stop people being exposed to the hazard. Photoelectric devices can be set to control how much anyone can enter a restricted space, such as a hand but not the arm, or an arm but not the body.
Figure 22: Example of a photoelectric light curtain used as a trip guardSingle light beams are not normally suitable because people can reach around the light beam and access the hazard. You can use a number of light beams so there are no gaps that people can reach through, around, under or over. When any of the beams are broken, the power is cut.
Consider carefully what distance a light beam curtain is placed from the hazard. If it is too close, someone can reach through the light curtain to danger faster than the control system can stop the machine. If the beam is too far away, someone can stay inside the protected area without interrupting the light beam.
You can use extra protection (such as extra light beams/curtains, safety mats or laser scanners) to monitor the area inside the light curtain. You can use photoelectric safety devices with other types of guard to make a safe zone where an operator has to access the machine frequently.
As photoelectric systems can fail without visible warning, any failure must not put a user at risk.
Photoelectric safety devices should meet and be installed to high performance standards, such as the International Electrotechnical Commission standard IEC Safety of Machinery ' Electro-Sensitive Protective Equipment.
With this type of guarding, a barrier moves towards the user when they approach the hazard making them step back, out of reach of the hazard. If push-away guards are not carefully designed and maintained then they too can become a hazard. Users need thorough training to safely use machinery guarded like this.
Figure 23: Example of a two-hand control
Only use this method to isolate people from machinery hazards as a last resort. Even when used properly, two-hand controls only protect the machine operator, not other people who may be near.
Two-hand controls should:
The rear and sides of the machine should be guarded by fixed guards to prevent stop access by other people.
Pressure-sensitive mats are designed to cut the machine's power if someone steps on them to access a dangerous part. Only use pressure-sensitive mats when you cannot use physical barriers or other methods of isolating people from hazards.
Pressure-sensitive mats use a number of well-spaced electrical or fluid switches or valves in a mat. The mat covers any entries to a restricted space. Pressure on the mat stops the automatic operation of the machine. You should design the guard so no one can step over or around it into a restricted area.
Operate and maintain pressure-sensing safeguard systems to the manufacturers' instructions. Keep records of any maintenance, inspection, commissioning and alteration to a presence-sensing system, as well as any test results. Make sure workers and health and safety representatives can access the records.
Because pressure-sensitive mats do not usually show any visible sign of failure, use a control system that shuts down the machine if a mat fails.
Figure 24: Pressure mat enclosing a robotLocking guards and gates need a responsible person (usually a manager) to hold the key at all times. This person must also make sure the gate is not opened until the machine is switched off, isolated and has stopped.
Only use locked guards and gates if after diligent trials, there are no practical alternatives. Senior management in association with staff should also write, approve and monitor any safe operating procedures and monitor the effectiveness of the safety process as a temporary means to minimise the hazards.
Isolation, hold cards and lock-out devices (see section 8.1.11 of this guideline) can also be used so a machine is not accidentally restarted.
Adjustable guards are made up of a fixed guard with adjustable elements that are moved to suit each task. They can be:
self-adjusting
' guards that are forced open by the entry of workdistance guards
' barriers that can be moved to a safe distance from the danger zone.Guards that move out of the way for each operation (automatic guards) need special care. Hazards can be created between the guard and:
Staff need full training on using and adjusting these guards. These guards are only effective when the people use them correctly.
Figure 25: The self-adjusting guard over the cutting wheel swings back as the cutting wheel cuts through steelEmergency stop devices should not be the only method used to control hazards. They are only a backup for other control measures. They should be red with a yellow background. Do not use emergency stops to lock-out the machine because the actuators can separate from the contacts. If this happens, the control will show the machine is off but it is actually on.
Do a hazard assessment when choosing an emergency stop device and consider:
Make sure emergency stop devices:
Other considerations include:
Badly placed emergency stop devices may slow shutdown in an emergency and encourage dangerous practices, such as:
When there is more than one device, use a safe procedure so machinery cannot restart during maintenance or other temporary situations (such as a blockage of product). A lock-out and tag-out system is essential to isolate the machine from a power source to stop accidental start-up.
When servicing emergency stop devices, actuators can separate from contacts, meaning the machine appears to be off, but because of the fault it is still on. This why emergency stops are unsafe to use as a means of lock-out.
It is good practice to paint safety guard posts or frames yellow and any mesh black so it can be seen through more easily and staff do not need to open the guards for observation as much.
So workers can easily see when a guard is out of place, it is good practice to:
Lock-out systems are used to safely isolate machinery from its power source. They are used when someone needs to inspect, repair, maintain, alter or clean the machine, or when it is to be withdrawn for assessment or repair. The method used to isolate depends on the type of machinery. Employers should develop these safe operating procedures with employees. Once a procedure has been put in place it should be strictly obeyed.
Employers must make sure there is a safe system to isolate all machinery from power sources.
They must:
Workers trained in the safe system of isolation for machinery must make sure the system is followed at all times.
If the machine is powered by electricity, the employer or principal should have a qualified electrician remove and keep the fuses. Where other sources of power are used, the parts that are removed to achieve isolation should also be kept in a place where they can not be accessed by other workers.
If access to machinery is required and it is not practical to stop it, employer, principal or duty holders must ensure that:
The competent person must be the key person to:
The competent person must make sure:
The competent person who isolated the machinery must be the one to remove the lock-out equipment and make the machine operational again. A procedure should be in place where this is not possible (such as where work is done over a number of shifts or the worker has gone home sick).
If the competent person cannot complete all steps in a planned isolation, they must make sure a competent person develops written procedures and that these are followed by the person doing the work.
Chains, clasps and locks are examples of devices that can be used to isolate machinery. Isolation devices must be reliable and clear. Each lock should:
Master or spare keys should be kept in a designated place, away from the workplace and under the control of an competent person. There must be strict procedures about when to use spare keys. They must only be used in an emergency after thorough safety checks are done.
Lock-out and tag-out cards should be used together and be attached to the power controls of isolated machinery. This reduces the chance of someone starting the machinery inadvertently. The cards must clearly state that under no circumstances should the machinery be connected to the power source or be started until the hold card is removed by the person named on the tag-out card. Include advice on the tag-out card of the actual or potential danger, where appropriate.
Figure 27: Shows various types of tag-out and lock out devices that can be used
Lock-out devices make sure people are out of the danger area before a machine can be started. They are mechanical-locking mechanisms used to physically lock machinery controls so they cannot be used.
Use lock-out devices when people have to work on or inside machinery and are out of sight of other people in the workplace. Anyone who has to work in a hazardous area should have a lock-out device that identifies who is protected by the device. The lock used with these devices should be durable and must only have one key, held by the operator.
Tag-out cards are sometimes referred to as danger tags, restricted-use tags and warning tags. Use a tag out card with lock-out devices and isolation to improve staff safety.
The duty holder must ensure that fences or guards are:
Even when there are mechanical methods to control hazards, other ways to minimise risk might still be needed, such as safe work systems or protective clothing and equipment (see section 8.3). Do not use only non-mechanical control measures to control hazards. They rely on human behaviour and need commitment management and enforcement to work effectively.
There are control measures that minimise the risk of harm that can be used with machine guarding. Some of these control measures are systems and others are activity-based, such as maintenance.
Work procedures are needed to make sure that hazard control measures are effective. All work procedures must:
Involving workers and health and safety representatives in hazard management is essential. They are most likely to know about the hazards of their work. They can help develop measures to eliminate, isolate or minimise hazards before an injury or incident occurs when:
Employers must train workers, supervisors and others so they can use hazard control measures and work safely.
Operators and workers must be supervised by a competent person to make sure hazard control measures are used correctly.
Work procedures should identify any maintenance needed to keep control measures effective. Looking at maintenance of control measures is an important part of the implementation process.
So maintenance can be done safely, consider:
Employees may need personal protective equipment when working with machinery that makes heat, fumes, noise or other hazards. Personal protective equipment must be provided by the employer and maintained and replaced when required. Standards New Zealand have a range of guidance relating to personal protective equipment.
Every workplace should have first aiders and first aid supplies. Employers should put first aid provisions in place based on the types of accidents, injuries and illnesses that could occur in the workplace. For more information, see WorkSafe's First Aid for Workplaces: A Good Practice Guide.
Employers must give staff this information in a way workers can easily understand it ' be aware of language and literacy issues.
Employers may also need to give information to others who enter the workplace, including cleaners, visitors and contract staff.
This could be a machinery instruction handbook or other written instructions that include:
Specific information about an individual machine should include:
Written information for the user should include:
A wide range of information sources can be used to help identify hazards, including:
A safe system of work is a formal work procedure developed after a systematic examination of a task to identify all the hazards. It defines safe ways to work so hazards and risks are minimised. When hazards cannot be completely eliminated or isolated, you may need to use a safe system of work.
An competent person must agree that a safe system of work is the only way to control a hazard. In this case, a competent person is someone with current knowledge and understanding of:
A safe system of work should never be used as the main hazard control without first assessing whether the hazards can be eliminated, or isolated with guarding, either provided by the manufacturer or retro-fitted to existing machinery.
Workers need extra training, more supervision and other protective measures when using a safe system of work. These also need to be documented.
Once control measures are in place, they must be regularly monitored and reviewed. To do this, it is useful to ask the following questions.
In order to answer these questions, you may need to:
When deciding when to monitor and review control measures, consider:
Documenting your chosen control measures helps show you have met your legal obligations. Keep records to track what has been done and what is planned; effective record-keeping can save time and money.
The level of documentation should be appropriate for the level of risk and control measures.
Choosing the right guard for the machine will create a physical barrier between a worker and the dangerous parts of the machinery. When choosing guards, careful attention to design and layout, and the use of the machine, can remove many health and safety hazards and can prevent health issues and injuries occurring.
Flowchart 7: Choosing a guardFlowchart 7 details how to make decisions around the most appropriate guard taking into account whether the machine parts require access.
Sections 7'11 of the HSE Act describe a way to identify hazards, manage health and safety issues, and follow up on health and safety matters.
Machine guarding options in order of preference:
If constant access is needed:
If there is no practicable way to guard a hazard, a safe system of work must be put in place (see section 10 of this guideline).
The basic rules for guard design are:
If a guard is used from another machine, check carefully that it:
When deciding what needs to be guarded, look at operational and non-operational parts of the machine. Start with obvious operational parts such as:
Then consider non-operational parts such as:
There are four main considerations when choosing material to make a guard:
When designing guards, consider what safe procedures are needed for their removal for repair, clearing jams and breakdowns.
Servicing matters to consider include:
Maintenance considerations include:
Exposed rotating cutting machinery includes:
Hazards arise from the exposed blades and risks include cutting people or entanglement.
Guards (or visors) that move must stay close to the work piece. The cutter's teeth can be exposed if the visor is:
Pulleys and drives are used in many machines. Nip-points are the main hazard. They must be guarded so no one can get entangled.
Interlocked guards are preferable for pulleys and drives. In some cases, a hinged section may be appropriate to access the machine when setting it. Design and install the guard so a tool is needed to remove and replace it.
Figure 30: Fixed guard for a pulley and drive preventing access to transmission machineryInterlocked guards are preferable for rotating shafts and rollers, such as:
Guards should stop loose clothing and long hair getting caught in rotating shafts. In addition to a guard, it may be appropriate to tell operators not to wear loose clothing (such as long-sleeved shirts or jackets) and tie long hair back or wear a head covering.
Figure 31: Fixed guard on rotating shaft or couplingConveyors move materials from one place to another. Types include belt, screw and bucket conveyors.
The main hazards of a conveyor are the many in-running nip-points, which can entangle, crush and abrade people. The drive system can also pose risks of entanglement or abrasion.
Fixed guards that enclose in-running nip-points and the drive mechanism are usually the best way to guard conveyors
Large conveyors, such as stockpilers, generally need both carry idlers and return idlers guarded where they are under high tension and accessible. This should be done to an appropriate standard, such as AS Conveyors ' Safety Requirements, AS . Conveyors ' General Safety Requirements or equivalent.
Figure 32: Typical guard for head and tail section of a conveyorElectrical isolation safeguards (which prevent access during most phases of machinery life) may not be effective when hazardous areas need to be accessed, such as during maintenance and set-up.
Because of this, conveyors should have appropriate drive power isolation, whether its power source is electrical, hydraulic, pneumatic or mechanical. A lock-out and tag- out system should secure isolation.
Each conveyor start location needs a clearly labelled 'stop' control. If any part of the conveyor operation cannot be seen from the start control, there must be a visible or audible signal to warn people nearby.
A lanyard-type pull-wire emergency stop is the best emergency stop for exposed belt conveyors where workers must access the belt area while the conveyor is in use (such as when placing and removing parcels at a transport depot).
The lanyard type means wherever someone is working on the conveyor, they can reach the emergency stop. Emergency stop controls should be manually reset before the conveyor can be restarted from its normal start control.
The machine design should let people do routine adjustment and lubricate and maintain the machine without removing guards or much taking apart. Wherever practical, people should be able to lubricate and maintain the machine from outside the danger area. If people need access to the danger area (such as for machine setting), use safe isolation procedures.
Make sure people working around conveyors are trained on how to use the machinery and are aware of the potential hazards.
AS Conveyors ' Safety Requirements and AS . (or equivalent) give more information on minimum safety requirements for the design, installation and guarding of conveyors and conveyor systems and training.
A press brake is a variable stroke machine generally limited to straight bending and forming of material, such as sheet metal and heavy gauge material.
For press brakes, the main hazards are:
The impact from both can have a pinching, crushing, cutting or shearing motion, which creates a risk to the operator of being crushed or cut.
Drive belts on press brakes have in-running nip points, which present a risk of entanglement and abrasion. Hydraulic hoses may leak or burst, causing slip hazards and workers getting sprayed with hydraulic fluids under pressure.
The front dies of a press brake and its sides and rear require guarding. Three forms of guarding for the front of the dies on a press brake are:
Where workers have to hold or stabilise the material, or need frequent access to closing dies, presence-sensing devices may be required to ensure safe operation. Presence- sensing devices may be light curtains or light beams. Automatic stops should also be guarded and back-gauging equipment is recommended.
Presence-sensing devices (cameras, light curtains or light beams) may not protect the operator in all circumstances.
Figure 33: Press brake with fixed guards and a presence-sensing light curtainOn occasions it may not be possible to perform work with the guarding system in place. Removal of or turning off a guard should only occur if the guard makes it impracticable to perform close work or jobbing and a hazard and risk assessment is carried out by a competent person. A safe system of work must be developed in conjunction with the employer and operators and approved by a competent person with appropriate knowledge and experience of machine safety.
In cases where guarding of any moving parts of the plant does not eliminate risks of entanglement, or where it is not practicable to guard the parts, people must not operate or pass close to the moving part unless a safe system of work is in place to reduce the risks.
Additional training, experience and higher levels of supervision, and other protective measures may be required and will need to be documented. For more information on safe systems of work see section 10 in this guideline.
The closed tool method of reducing the press brake's opening to 6mm limits the risk of introducing a part of the body into this hazardous zone. The distance between the point of the upper tool and the top of the bottom die is where the 6mm is measured from.
Where possible, the closed tool method should be used with a safety light curtain, a laser beam device or a two-hand control device.
Using robots can remove the more traditional hazards of working with machinery. They can do high-risk work, such as in the biotechnology field.
It is wrong to think that robotic operations are safe just because there is little or no worker interaction. Hazards when using robotics can come from:
Hazards can also come up during installation, repair and maintenance. There may also be biological, chemical or environmental hazards.
A hazard assessment should be done to ensure workers' safety during all phases of the machinery's life and use. Follow a hazard management process (with reference to the manufacturer's instructions) during installation or commissioning, testing, start-up, repair and maintenance.
Robots have inherent dangers. Some of the hazards of industrial robot use include:
Industrial robots can be made safe using one or more guarding and presence-sensing devices. Control measures include:
Designers, manufacturers and suppliers of robotic systems have the same obligations as designers, manufacturers and suppliers of other machinery (HSE Regulations 66 and 67, and section 18A of the HSE Act).
Figure 34: Robot cell showing Levels 1, 2 and 3Robot safety has different hazards and precautions in each of the three levels around a robot workstation.
Fixed or distance guards at (Level 1) are practical as long as the guard does not interfere with the mechanism of the robot. Someone should have to use tools to remove the guards to enter the restricted danger area. Guards or fences should be placed so people cannot reach into a restricted area. Any openings for feeding material in should be designed to keep every part of a person away from any hazard.
To stop trapping, any fixed barriers should be at least 500 mm from the robot work envelope (extreme reach of the robot arm and tooling).
Design and place presence-sensing devices (such as photoelectric curtains) to detect if anyone enters a restricted space or danger area (Level 2). The device must stop the automatic operation of the robot when entry is detected. Operation must also stop if this device fails.
You can use laser scanners or pressure- sensitive mats as a back-up safety protection for high-risk machinery in areas inside the primary light curtain. This way the system cannot restart while someone is inside the area protected by a light curtain.
Because robots are highly technical and programmable, consider extra safeguards beyond just guarding moving parts. These include making sure:
If people have to enter the robot cell (Level 2) while the robot is working, the control system should make sure the robot runs with reduced force. The robot also needs a sensor to stop it immediately if it hits someone.
Safe operating procedures also minimise some of the risks of working with robotics. A safe work system needs procedures for entry, including who can access the robot to do identified tasks, maintenance and repair. Inspecting and maintaining a robot can present different hazards from working with the robot. Assess all hazards for risks.
Staff must be trained to control the hazards of working with industrial robot machines. Inadequate training can increase risks at most stages of robot operation.
Robots usually have programmable electronic start and control systems. These should be protected from unauthorised access, such as by putting them in a lockable cabinet or room. Make and place controls so people cannot accidentally start the robot. This can be done a number of ways, including shrouding, guarding, gating or appropriate positioning.
If people can access the robot, it must be isolated from its power source.
For more information see AS Safety of machinery ' Functional Safety of Safety-Related Electrical, Electronic and Programmable Electronic Control Systems. AS . Safety of machinery ' Robots for industrial environments ' Safety requirements
Robots should have master switches to cut power to any moving part of the robot. This can be the same device as an emergency stop. You should be able to lock the master switch in the isolating position so it needs to be manually reset.
In this guideline, a safe system of work means the steps which if followed, will minimise the hazard arising from doing a specific task or set of tasks, as far as practicable.
Flowchart 8: Developing and maintaining a safe system of work for specific tasksFlowchart 8 gives details of the key factors that should be considered when developing a safe system of work.
Apart from assessing guarding options for machinery, all workplaces must have safe systems of work in place for tasks and processes that take into account:
For the safe system of work to be robust, anyone who could come in contact with the machine should be consulted. This includes:
Before a safe system of work can be put in place, employers must identify and assess all hazards, such as:
Then they must develop a way to control each hazard, such as:
Any operator using a safe system of work must be competent to do the job and be supervised by a competent person. Employers must have a training programme in place that works for:
Emergency procedures must be in place and staff trained to use them. This includes information, signage and emergency equipment.
A workplace cannot opt for a safe system of work that does not include guarding to control a hazard, without first considering all possible guarding controls.
Once agreement is reached on what a safe system of work is for a machine, the duty holders (employer or principal) must approve it, along with a competent person and document it.
Before designing a safe system of work, a competent person must establish that all possible guarding options were considered, they must explain why none could be used, and give advice on the residual risks that remain. The competent person must also be consulted and approve the safe system of work.
Every safe system of work needs regular reviewing to take into account:
Any proposed changes should involve anyone previously consulted on the safe system of work. The system and any changes need testing before they are included in the safe working system and approved by the duty holder.
Please note some these definitions are based on the Health and Safety in Employment Act (HSE Act) but should not replace legal advice.
All practicable steps is defined in the HSE Act.
Briefly, it means doing what is reasonably able to be done in the circumstances, taking into account:
Current state of knowledge is what is known about the hazard or risk, including actual or potential harm, and ways of eliminating, isolating or minimising the risk.
Dynamic forces are forces resulting from movement of an object, in this case movement of a machine.
Functional validation of a machine is the process of testing that a safety-related device performs as the designer intended.
Group control is a control that protects more than one person in the vicinity of the machine in addition to the operator.
Harm
Hazard
Inching means limited motion of machinery where dangerous parts of machinery are exposed during cleaning, setting, adjustment or feeding material and, depending on the machine and industry, may include the terms jog, crawl and pulse.
Ionising radiation is radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from the orbit of an atom, causing the atom to become charged or ionised. Examples are x-rays and gamma rays.
Machine life cycle is the process beginning with design, continuing through manufacture, sale, transport, installation, test, use and maintenance, ending in disassembly and disposal.
Machinery is a collective term for machines and their parts. A machine is considered to be any apparatus that has interrelated parts and is used to perform work; machines may include an engine, motor, or other appliance that provides mechanical energy derived from compressed air, the combustion of fuel, electricity, gas, gaseous products, steam, water, wind, or any other source; and includes:
Non-ionising radiation is in the electromagnetic spectrum where there is insufficient energy to cause ionisation. It includes electric and magnetic fields, radio waves, microwaves, infrared, ultraviolet, and visible radiation.
Plant includes:
It is a general name for machinery, equipment, appliance, implement or tool and any component or fitting or accessory of these. It can include things as diverse as presses in a foundry, excavators and trucks in mining, and photocopiers in an office. It can range from electric drills, lifts, escalators, tractors, hand trolleys, cranes, and other lifting gear to arc welding gear.
Prime mover means an engine, motor, or other appliance that provides mechanical energy derived from steam water, wind, electricity, gas, gaseous products, or any other source. It includes any device which converts stored or potential energy into movement or mechanical energy.
Risk means a combination of probability and the degree of possible injury or damage to health in a hazardous situation.
Safe by position means so positioned that any person cannot reach or gain access to the dangerous parts.
Safety requirement specifications is the means by which the hazards of a machine or process are controlled to reduce risks of harm to those working at or near the machine or process.
Safe operating procedures are written instructions that detail the steps that will be performed during a given procedure; including information about hazards and how these hazards will be controlled.
Safe system of work means a formal procedure which results from systematic examination of a task in order to identify all the hazards. It defines safe methods to ensure that hazards are eliminated or risks minimised.
Safety life cycle refers to the safety of the machine, its assembly, its functioning and decommissioning at the end of its life.
Securely fenced means so guarded that the arrangements provided ensure that the dangerous part is no longer dangerous. There is no longer a reasonably foreseeable risk of injury to any person employed or working in the place of work, even a person who is careless or inattentive while in the vicinity of a machine or using a machine.
Shall and must are used in this guideline in places where there is a legal requirement to achieve the desired result.
Should is used in this guideline as a way of indicating a preference. It does not indicate a mandatory requirement as other alternatives may achieve an equivalent result.
Supplier is anyone who sells or hires out machinery. They have a number of legal responsibilities.
Swarf is metal removed from a workpiece during machining. It may be in the form of small 'chips', tightly curled strips, or long 'ribbons'.
Transmission machinery is a mechanism that transfers movement from the prime mover to the machine. It can be a shaft, wheel, drum, pulley, system of fast and loose pulleys, gearing, coupling, clutch, driving belt, chain, rope, band or other device.
Validation is the process of confirming that all required steps of the safety life cycle are tested, implemented, working and verified.
AS is the Australian Standard for managing machinery hazards. The standard is available in four series. Their organisation is shown in the chart below.
Series 1, or to use its full title ' AS .1, Safety of Machinery series, has 26 Parts under the eight headings in the diagram above. The 26 Parts are European (EN) and Internationally based (ISO) safety and design standards with some modifications to meet Australia's safety practices and regulations.
The series gives designers, manufacturers, suppliers, employers and users of machinery guidelines to help reduce the risks of working with, or near machinery.
Designers, manufacturers, suppliers, employers and users of common manufacturing machinery not listed above can find specific guidance in:
People looking for more information about electro-sensitive safety devices (beyond what is in AS Series 4) should find it in IEC (series) Electro-sensitive Protective Equipment.
AS .1- Safety of Machinery includes:
Terms and definitions
Gives users a set of terms and definitions that are used in other machinery safety standards, as well as in discussions of machinery safety.
Basic terminology and methodology
Specifies the basic terminology and methodology to be used by designers to achieve safety of machinery.
Technical principles
Defines the technical principles needed to design safe machinery. Does not deal with injury to domestic animals, property or the environment.
Principles of risk assessment
Specifies principles for doing a risk assessment so the knowledge and experience of the harm related to machinery is gathered together to help assess risks during all phases in the life of machinery. Gives guidance on the information needed to carry out risk assessments and a brief outline of some of the techniques available.
Reduction of risks to health and safety from hazardous substances emitted by machinery ' Principles and specification for machinery manufacturers
Gives principles for controlling risks to health from the emission of hazardous substances from machinery.
Design principles ' Terminology and general principles
Specifies the ergonomic design principles and terminology to be used by designers.
General principles
Gives safety requirements and guidance on the principles to be used in the design of the safety features of machinery control systems. Categories are specified and the characteristics of the safety functions are described.
Validation
Specifies the conditions and procedures to be followed for the validation by both analysis and testing of safety functions provided and safety category achieved by the safety-related parts of control systems using the design rationale, including risk analysis, provided by the designer. When validating programmable electronic systems, this standard does not give complete requirements and needs the use of other standards such as the AS series.
Guards ' General requirements for the design and construction of fixed and moveable guards
Specifies requirements for the design and construction of fixed and movable guards that protect people from mechanical hazards in machinery.
Principles for design and selection
Specifies principles for the design and selection of interlocking devices used with guards. The principles are independent of the energy sources used on the machine.
Prevention of unexpected start-up
Gives ways to stop unexpected machine start-up to use at the design stage, including energy isolation and dissipation. Applies to all forms of energy, including those external to the machine, such as wind, gravity and electro-magnetic.
Emergency stop ' Principles for design
Explains what an emergency stop needs to do and gives the design principles, regardless of the energy source used to control the functions. It does not apply to hand-guided machines, hand-held portable machines or to machines where having an emergency stop would not reduce the risk to anyone.
Basic human body measurements for technological design
Gives information and descriptions of anthropometric (human body) measurements that ergonomists and designers of workplaces can use to compare population groups.
Use this standard to help design work stations where people stand, sit or reach controls or other items. There are pictures to help.
Principles for determining the dimensions required for openings for whole body access to machinery
Gives the smallest size an opening can be when someone has to go through it to access machinery. There may be extra requirements for mobile machinery.
Use this standard to help design openings, such as for people to walk upright through or climb via a vertical ladder. Sizes are also given for users wearing personal protective equipment or carrying an injured person.
Principles for determining the dimensions required for access openings
Gives minimum sizes for access openings in machinery. Additional space needs are also given. There may be extra requirements for mobile machinery.
Use this standard to help design access openings for putting body parts into a machine. It allows for different postures, such as standing or crouching.
Anthropometric data
Gives the human body measurements needed to calculate the size of access openings in machinery. The measurements come from European surveys. Use AS . for information on how to source human body measurements.
Safety distances to prevent danger zones being reached by the upper limbs
Gives the minimum safety distances between a barrier and a danger zone of a machine to stop anyone over three years old reaching the danger zone with their arms. Only use this standard when distance alone can remove the hazard. This standard does not protect against radiation or substances coming out of the machine.
Safety distances to prevent danger zones being reached by the lower limbs
Gives safety distances to keep people's legs out of danger zones of machinery. Only use these distances when distance alone can remove the hazard, and there is no chance that someone can reach the hazard with their arms.
Minimum gaps to prevent crushing of parts of the human body
Gives minimum gaps in machinery to stop parts of the body being crushed.
General principles for human interaction with displays and control actuators
Gives general principles to design displays and controls so operators can use the machine efficiently.
Displays
Gives the ergonomic requirements for visual, audible and tactile displays on machines. It helps you choose, design and place any displays to avoid ergonomic hazards.
Control actuators
Helps you design, choose and place manual control actuators to suit the needs of the task and the operators.
Requirements for visual, auditory and tactile signs
Explains how to give safety information, using sight, sound and touch. It sets out a system of colours, signs, markings and other ways to show hazards and help in emergencies.
Requirements for marking
Gives rules on markings on machines for:
Requirements for the location and operation of actuators
Gives the safety requirements for actuators run by hand or other body part. It applies to both single actuators and groups of actuators.
System of auditory and visual danger and information signals
Gives a series of danger and information signals (both sight and sound) that indicate urgency and can be differentiated from each other. This standard does not apply to signals covered by specific standards or conventions, such as fire alarms, public transport or navigation signals.
Design of controls, interlocks and guarding ' Two-hand control devices ' Functional aspects and design principles
Gives the safety requirements for two-hand controls.
This standard helps you design and choose two-hand control devices, using a risk assessment. It helps stop work-arounds and faults. It also gives standards for two-hand control devices with a programmable electronic system.
Safety distances and safety gaps ' Positioning of protective equipment with respect to the approach speed of parts of the human body
Explains how to work out the minimum distances for sensing or actuating devices of protective equipment to a danger zone. The safety distances are based on hand or arm approach speeds and the response time of the machine.
These devices are:
Materials forming and shearing ' Mechanical power presses
Gives the safety requirements and measures to design, build and supply mechanical presses that work cold metal or material partly of cold metal. You can use the principles in AS .1 for work with hot metal and tongs, but you might not be able to apply them fully. Read this standard with AS .1 (series).
This standard also covers presses intended for work with cold metal, but are used in a similar way to work other materials (like cardboard, plastic, rubber or leather) and metal powder.
The requirements in this standard take account of intended use. This standard presumes access to the press from all directions and gives the safety measures for both the operator and other people.
This standard also applies to accessories that are vital parts of the press.
Materials forming and shearing ' Hydraulic power presses
Gives the safety requirements and measures for hydraulic presses that work cold metal or material partly of cold metal. You can use the principles in AS .1 for work with hot metal and tongs, but you may not be able of apply them fully. Read this standard with AS .1 (series).
This standard also covers presses intended for use with cold metal, but are also used in a similar way to work other sheet materials (like cardboard, plastic, rubber or leather) and metal powder.
The requirements in this standard take account of the intended use. This standard presumes access to the press from all directions, deals with the hazards and gives safety measures for the operator and other people.
This standard also applies to accessories that are vital to the press.
Safety of machinery ' Materials cutting ' Milling machines (including boring machines) ' Safety requirements
Gives the safety requirements and measures to design, build, supply, install, take apart, transport and maintain milling and boring machines.
Robots for industrial environments ' Safety requirements
Gives requirements and guidelines to design, build and use industrial robots and robot systems safely. It describes some hazards of working with robots and how to avoid them.
While this standard does not cover non-industrial robots, the safety principles can be used for them. Non-industrial robot applications include:
AS .4- Safeguarding of Machinery includes:
Safeguarding of machinery ' Installation and commissioning requirements for electro-sensitive systems ' Pressure-sensitive devices
Explains the requirements to install and commission pressure-sensitive fixed mats, floors, edges and bars that will be used with plant and machinery.
You will need to adapt or extend this standard if safety devices are to be used in other situations, such as protecting children or in exposed places with wide temperature limits.
The process can be used to identify hazards, assess their risks and identify controls to implement in relation to safeguarding of machinery and plant. This risk management process is outlined below.
These may include:
Once the risk has been assessed, where required, choose control measures to eliminate the risk. See section 4 of this guideline for options to control hazards.
The risk may then be assessed after taking into consideration how much the hazard controls will prevent harming workers.
This list of standards is included for general guidance only, and is not inclusive of all standards. Readers should check the latest version of a standard at the time of use.
New Zealand has performance based legislation and there is a duty on designers, manufacturers, suppliers, importers, sellers and employers to take all practicable steps to eliminate, isolate and/or minimise hazards. Complying with the requirements of an appropriate best practice standard may be considered as taking all practicable steps to ensure safety of machinery and plant. Evidence of failure to comply with the requirements of the best practice standard may be used as evidence in proceedings for an offence under the HSE Act.
Some standards listed may be out of date and not available. The hierarchy for application of standards are that if there is no New Zealand Standard for a subject, the first appropriate standard to use is an Australian standard. If there is no Australian standard for the subject, the next most relevant standards are ISO, European or British standards. If there is no such standard available, then refer to the American, Canadian or other recognised relevant standards. The criteria will also be which standard or guideline can provide the latest current state of knowledge and good practices about the safety of a plant or process.
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