Protecting life and limb: machinery guarding
Although the advent of new technology has brought with it a number of hazards such as those associated with IT, machinery guarding remains an important issue. This is evident from the number of workers killed or injured by machinery each year and hardly a week goes by without the Health and Safety Executive (HSE) reporting on prosecutions involving machinery guarding issues.
Moving machinery can cause injuries in many ways, including the following.
- People can be struck and injured by moving parts of machinery or by ejected material. Parts of the body can also be drawn in or trapped between rollers, belts and pulley drives
- Sharp edges can cause cuts and severe injuries, sharply pointed parts can cause stabbing or puncture the skin, and rough surface parts can cause friction or abrasion
- People can be crushed, both between parts moving together and against a fixed part of the machine, wall or other object
- Parts of the machine, materials and emissions (such as swarf, sparks and steam) can be hot or cold enough to cause burns or scalds; electricity can cause electrical shock and burns
- Injuries can also happen due to lack of training and poor procedures to deal with breakdowns and blockages.
Injuries associated with these hazards are often severe, unpleasant, debilitating and can be fatal. So what should be the practical approach to deal with these hazards? What does the law require?
The old Factories Act 1961 took a hard line on the guarding of dangerous machinery when at s.14 it required every dangerous part of machinery “to be securely fenced”. This was an absolute duty that imposed a high standard of guarding for dangerous moving parts of machinery. Being an absolute duty meant that secure fencing had to be achieved irrespective of cost and practicalities, and in practice there was little or no defence.
Today, the Provision and Use of Work Equipment Regulations 1998 (PUWER) regulate the guarding of dangerous parts of machinery and they take a different and more flexible approach.
Regulation 11(2) specifies the measures to be taken to prevent access to the dangerous parts of the machinery and achieve compliance with PUWER. The measures are ranked in the order they should be implemented, where practicable, to achieve an adequate level of protection. The levels of protection are:
- Fixed enclosing guards.
- Other guards or protection devices such as interlocked guards and pressure mats.
- Protection appliances such as jigs, holders and push-sticks.
- The provision of information, instruction, training and supervision.
It is important to note that regulation 11(2) of PUWER is qualified by the term “practicable”. This has been defined in a number of court cases as meaning “physically possible” and “technically feasible” irrespective of cost. Therefore PUWER sets a higher standard than those legal requirements qualified by “so far as is reasonably practicable”, but lower than the absolute duties as found in the Factories Act 1961.
There are also duties imposed on machine manufacturers and suppliers to make sure that machinery is properly guarded. Section 6 of the Health and Safety at Work, etc Act 1974 places a duty on manufacturers, suppliers and designers of equipment for use at work. It places a general health and safety obligation on anyone in the supply chain, so far as reasonably practicable, for when articles for use at work are being used, set, cleaned or maintained. This obligation includes providing information and instructions on safe use, including any subsequent revisions to that information.
The guarding options
The guarding options are well explained by the HSE and the main characteristics of each option are as follows.
The fixed guards referred to in regulation 11(2) have no moving parts and are fastened in position. They are kept in place either permanently, by welding for example, or by means of fasteners (screws, nuts, etc) making removal/opening impossible without using tools, eg an Allen key. If, either by themselves or in conjunction with the structure of the equipment, they enclose the dangerous parts, fixed guards meet the requirements of the first level of the hierarchy. Note that fixed enclosing guards, and other types of guard, can have openings provided that they comply with appropriate safe reach distances.
Other guards in regulation 11(2) include moveable guards which can be opened without the use of tools, and fixed guards that are not fully enclosing. These allow limited access through openings and gates for feeding materials, making adjustments, cleaning, etc. Moveable guards may be power-operated, self-closing and adjustable and are likely to require an interlocking device so that:
- The machine cannot operate until the guard is closed
- If the guard is opened, the machine will stop
- When the guard is closed, the machine can operate but the closure of the guard does not by itself initiate operation.
Such interlocking devices must be arranged so that they are difficult to defeat and if they fail the machinery should be inoperable.
Other guards can include “protection devices”, which are devices that do not prevent access to the danger zone but stop the movement of the dangerous part before contact is made. Typical examples are mechanical trip devices, electronic devices such as light curtains, pressure-sensitive mats and two-hand controls.
Protection appliances such as jigs are used to hold or manipulate a work piece at a machine while keeping the operator’s body clear of the danger zone. They are commonly used in conjunction with manually-fed woodworking machines and certain other machines, such as band saws for cutting meat, where it is not possible to fully guard the cutting tool. These appliances will normally be used in addition to guards.
Adequate information, instruction, training and supervision are always important, even if the hazard is protected by guarding measures; however, they are especially important when the risk cannot be adequately eliminated by the guards.
In February 2014 alone, the HSE reported these serious accidents.
- A Burnley bakery appeared in court after an employee had the tips of two fingers chopped off by a pasty-making machine. The company was prosecuted by the HSE after an investigation found part of a metal guard had been deliberately removed, allowing employees to add fillings to the machine while it was still operating
- In another case, a food company was prosecuted after an employee lost the ends of two fingers in a poorly-guarded machine. The 45-year-old worker suffered partial amputation of the ring finger and serious injury to the little finger of his right hand after it was caught in a rotating drum that he was trying to clean
- In further incident at a plastic recycling plant, a company was fined after a worker suffered a broken arm when it became caught in machinery. He was checking a rotating auger, which was pushing materials through a metal tube, when his sleeve got caught on a bolt protruding from the electric motor driving the auger spiral. This twisted his sleeve so severely it acted like a tourniquet and broke his arm.
Machine guarding is not an outdated historical issue. It is a live issue that needs constant and urgent attention. Dangerous parts of machinery must be properly guarded or accidents causing serious injury will continue to happen.