Safety in Workshops

Introduction

In general, personnel in the various mechanical workshops of the University know by long training how to use workshop tools, machine tools and equipment. Only trained and competent persons should be admitted to these mechanical workshops and permitted to operate equipment. Untrained personnel should be discouraged from using workshops unless they have acquired some degree of proficiency as determined by the workshop supervisor.

This policy on Safety in Workshops has been written not only to provide novices with appropriate safety procedures but also to assist trained workshop personnel with the provision of a reference document outlining the general principles of safe working practices relevant to the mechanical engineering aspects of the workshop environment. It relates to specific areas where definite safety measures are required for workshop operations. This policy is written as an addition to and not as a substitute for general safety principles applicable to all types of workplace viz: fire precautions, correct use of personal protective equipment, hygiene standards, toxic processes, workplace noise and correct manual handling techniques. Information on these areas of safety is given in other appropriate sections of the Safety and Health Manual.

Guidance is also available in Australian Standard, AS1485 - 1983: Safety and Health in Workrooms of Educational Establishments. Copies of all Australian Standards are retained in the Mathematics and Physical Sciences Library.

General Requirements of Safety in Workshops Policy

The following rules apply to all workshop personnel, whether they are permanently employed in the workshop or just occasional users:

• Keep the workshop clean and tidy at all times;
• Always seek instruction before using an unfamiliar piece of equipment;
• Only use tools and machines for their intended purpose;
• Report all damaged equipment and do not use it until it has been repaired by a qualified person;
• Where machine guards are provide they must be kept in place;
• Never distract the attention of another staff member when that person is operating equipment and never indulge in horseplay;
• Always use the appropriate personal protective devices and check that they are clean and in good repair before and after use;
• Long hair needs to be restrained by either a tie or hat;
• Never use compressed air for cleaning clothing and machinery;
• Report all hazards and unsafe conditions and work practices.

It is the responsibility of the officer in charge of the workshop to ensure that staff who use the workshop only occasionally adopt the same safety precautions and procedures as full-time workshop personnel.

Equipment and Services

Machinery Installation

Manufacturers of machine tools incorporate various safety features many of which concern the safety of the machine itself. Machinery, plant and equipment should be inspected on delivery to ensure its safety features comply with the requirements of the Department of Occupational Health Safety and Welfare and that any other safety features requested on purchase are correctly fitted. Section 23 of the Occupational Health Safety and Welfare Act indicates the statutory duties of designers, manufacturers and suppliers of machinery in respect of its safe installation and use at the workplace.

Each machine should be inspected prior to commencement of work to ensure that all guards are correctly fitted.

Machinery, plant and equipment should be installed so as to ensure that sufficient space and safe footholds are provided around an individual machine to allow for normal operation, group instruction, adjustment and ordinary repairs.

Machine Controls

Machine controls should be in accordance with the following requirements:

• Start-stop controls of the push button type easily visible, readily accessible and incorporating both no-volt and overload release;
• Start buttons should be shrouded or recessed, coloured green and the word START shall be indicated on or near the button. Starting levers and handles should have a provision for automatic retention in the "off" position;
• Stop buttons shall be long, easy to locate, coloured red and clearly marked with an identifying symbol or the word STOP. Each machine shall have a stop control for disconnecting power and the control should be readily and safely accessible to the operator from the normal operating position;
• Emergency stop buttons of the mushroom-head type, prominently and suitably labelled, should be installed at selected positions so that pressing any one of the buttons will immediately operate the circuit breaker and disconnect the supply from the machines.

Machine Guards

Use of any power machinery introduces the danger of personal injury due to pinching, cutting, tearing or crushing. This danger can be minimised by the wearing of suitable clothing and fitting suitable guards to protect both the operator and passing traffic.

Guards should be made of unperforated material but designed so as to allow access for inspection and maintenance and should not make the operation of the machine more difficult.

An obvious function of a machine guard is to keep the operator's body, fingers, clothing and arms away from the danger point without impeding the operation or obstructing vision.

Another function, which is less obvious, is to prevent a hazardous piece of material from striking the operator e.g. a grinding wheel guard. A suitable guard should not only be shaped to contain the hazard but must also be of sufficient strength to prevent the hazard from being flung out at the operator.

A guard may serve a further function in preventing the fitting of an unsafe attachment e.g an oversize wheel to a grinder. This aspect of guard function also applies to interlocks where the machine cannot be started or operated unless the guard is in position.

Service Installations

Electrical equipment and apparatus should be designed and constructed so as to prevent danger from shock and fire and should always be maintained in a safe and good condition. The equipment must comply with the relevant requirements of Australian Standard AS3000 and the requirements of the State Energy Commission. (WA)

Any electrical equipment should be checked by a qualified electrician at least quarterly and a tag should be affixed to the item indelibly marked with the type of item concerned, the name of the owner of the item, the license number of the electrical worker who carried out the inspection and test and the date on which the inspection and test was carried out; unqualified persons must not interfere with or alter any electrical installation. All electrical power distribution circuitry should be protected by core-balance earth-leakage protection of 30mA sensitivity.

A gas and/or oil fuel installation, including flues, should be carried out to the requirements of the State Energy Commission (WA). The gas supply must be automatically interrupted at the occurrence of system failure.

Maintenance

A programme of regular inspection and maintenance should be in place and carried out on all machines in addition to routine daily surveillance. Cleaning of machines must not be carried out while they are in motion; lubrication and adjustment must be carried out only by the person authorised to do the work.

Equipment in General Use

The following sections provide general information on the various classes of workshop equipment in general use. Detailed information on individual types of tools and machines in each class can be found in Australian Standard AS1485 -1983.

Hand Tools

Workshops contain an assortment of hand tools and it is essential that only the correct tools be used for a particular job. Improvisation is not allowed if the correct tool is not immediately available. Defective tools must not be used.

A hand tool should be fitted with a securely fixed handle designed to suit the tool to which it is fitted and the purpose for which the tool is to be used. A place should be provided for each tool e.g toolbox, rack or shadow board, and the tool should be returned to such a place when not in use.

An edged tool should be kept sharp and ground to the correct cutting angle. Any sharp tool such as a knife or chisel should not be carried in the pocket but should be placed in a scabbard and carried in a toolbox.

Portable Power Tools

A powered hand tool should be of the single-purpose type, of robust construction and used only for the purpose for which it was designed. The tool should be placed in a suitable store when not in use and the serviceability at least checked visually for damage to parts and attachments.

Portable electric power tools should be provided with a non-detachable flexible cable or flexible cord which should be kept as short as practicable to avoid a possible trip hazard and to obviate damage to the cable or cord caused by objects being dropped on it. A suitable plug, preferably an unbreakable type, should be connected to the flexible cable. In addition portable electric power tools and extension leads should be checked periodically by a qualified electrician and the check should include an earth continuity test by a high current testing device.

Where possible the cable or cord should be run at a high level, dropping down at the working position and not run across the floor. It is recommended that where a 240V portable tool is to be used on a supply system not protected by a core-balance earth-leakage protection device each tool should be so protected or double insulated.

Portable hand held electrically power tools must have Residual Current Devices (RCD) located in the power supply either at the wall socket or installed in the buildings fuses. OS&H Regulations (1996) section 3.60.

Drilling Machines

A properly designed drift should be used to remove tapered drills or chucks from the spindle. Fixtures, machine vices or workpieces should be clamped to the table or set against stop bars. Strip material or non-ferrous material should not be drilled unless it is securely clamped or held against a stop.

When the flutes of a drill become choked with swarf, the machine must be stopped before the swarf is removed. Hinged guards should be provided to completely enclose the upper part of the drill spindle, pulleys and belt drives.

Operators need to be aware of the danger of leaving chuck keys in the chuck after removing or replacing a drill.

Grinding and Polishing Machines

A grinding or polishing machine is any power-driven machine used for grinding, polishing and buffing of metals by means of an abrasive wheel, scratch-brush wheel or grinding and finishing belt or other similar equipment.

Every grinding or polishing machine which generates dust must be provided with an efficient exhaust system or dust abatement system. The exhaust system should consist of a hood ducted to an exhaust fan in such a manner as to carry away the dust to a device whereby the dust is separated from the air and is prevented from entering the workroom.

All personnel engaged in grinding or polishing operations must wear suitable eye protection.

Grinding wheels should be properly mounted and, where necessary, fitted with a bush of suitable material between the wheel and the spindle. So far as practicable and consistent with the nature of the work, a guard of sufficient mechanical strength should enclose the grinding wheel.

It is necessary to prevent vibration, which may be dangerous, can cause uneven wear and mark the workpiece. Vibration can be caused by incorrect wheel balance, lack of rigidity in the machine, loose bearings or incorrect use of the work rest. Where the wheel is belt driven, incorrect fitting of the belt fasteners may be a cause of vibration.

In pedestal or bench-type grinding machines an eye screen should be provided for hand-held work and the area of the screen should be large enough to discourage the operator from looking around it. The screen should always be in place and maintained at an adequate transparency.

Every grinding wheel should be positioned so that when in use the plane of rotation is not in line with any door, passageway, entrance or a place where someone regularly works.

Finishing machines should be guarded with only the working face of the belt exposed and the belt should be mounted such that it rotates away from the operator wherever practicable. Before use the condition of abrasive belt should be examined and replaced if worn and the correctness of the tracking of the belt should be checked by rotating the belt by hand. If necessary the belt should be adjusted and finally checked with a trial run. Where possible suitable jigs or fixtures should be used to hold or locate the workpiece; the workpiece should never be held in a cloth or any form of pliers and gloves must not be worn when using a finishing machine.

Lathes

All controls must be in the neutral position before the lathe is started and the isolating switch must be off while adjustments are made to the machine e.g. gear changing, when the machine is not in use, or to remove swarf.

Chuck jaws, centres and retaining screws should be maintained in good condition and tools, measuring instruments or any other object should not be kept on the moving saddle, lathe bed or head stock.

For capstan lathes, stock bar guards should be provided and and kept adjusted so that the bar stock does not project beyond the limits of the guard. The chuck face-plate or other holding device should be effectively guarded where practicable.

Milling Machines

Operators of milling machines should observe the following:

• exercise care when using fast traverse levers in order to avoid running the job into the cutter and never attempt to remove the arbor nut by applying power to the machine;
• clamp the job or vice firmly on the table before starting the machine, and, where necessary, to provide steady supports to prevent vibration;
• the use of the correct type of handling equipment when heavy cutters are involved and the use of a chip guard when a fly cutter is used;
• when an unguarded cutter is in motion, the hands and fingers must be kept well away from the cutters.

Metal-Cutting Guillotines

The following requirements apply to the safe use of metal-cutting guillotines:

• Guards must be provided to prevent the operator's fingers from contacting the knife or clamp from either the front or rear of the machine. Only one person should be allowed to operate the machine at the one time and where long material is being cut and cannot be adequately supported by the work table, additional supports should be provided.
• A hand-operated guillotine should be made inoperative when not in use either by removal of the handle or by the use of a locking or similar device.
• The shear edges of the blades should be maintained in good condition and blade clearance must be adjusted in accordance with the manufacturer's recommendation appropriate to the thickness of the material being cut.
• Waste scrap metal provides a hazard for the hands and protective gloves should be worn when the metal is handled. A container should be provided for waste material from the guillotine.

Power Hacksaws

An automatic knock-off switch should be used at all times and a regular check should be carried out to ensure it is in good order. The work must be secured, adequately supported and the length of any overhang should be clearly indicated to avoid it being a hazard to any other person.

Woodworking Machinery

Woodworking machinery includes circular bench saws, bandsaws, thicknessers, spindle moulders and planing machines.

The requirements for woodworking machinery are extensive and are given in Section 9 of Australian Standard AS1485-1983 and Australian Standard AS1473- Code of Practice for the Guarding and Safe Use of Woodworking Machinery.

Harmful Substances and Processes

General Considerations

There are several points in relation to chemical safety which are particularly relevant to workshops. These include:

• Harmful or potentially harmful processes should be carried out using properly designed and well maintained equipment and where practicable in separate areas restricted to a minimum of persons;
• If harmful concentrations of fumes or gases develop in certain processes, specific provision should be made for their extraction using local exhaust ventilation in addition to the general ventilation of the workshop;
• Provision should be made to afford protection against chemical agencies such as harmful dusts, mists, vapours;
• Chemicals bearing trade names should not be used unless the supplier or manufacturer provides a material safety data sheet giving full information on the precautions which need to be taken when handling the chemical;
• The possibility of toxic or flammable gases existing or being generated should be indicated by prominently displayed notices.

Requirements and precautions to be followed for specific workshop processes are detailed in Australian Standard 1485-1983. Regulations 735 to 755 of the Occupational Health Safety and Welfare Regulations apply to welding and cutting processes and spray painting operations.

Solvent Degreasing

The following solvents are permitted for use in workshops:

• 1,1,1, trichloroethane

  This should always be used in a fume cupboard and only for small scale operations;

• trichloroethylene & perchloroethylene

  These should only be used in equipment specifically designed and in a well ventilated area free from draught. These solvents have anaesthetic properties and are harmful when inhaled or on contact with the skin producing:

  • headaches, nausea, vomiting, mental confusion, visual disturbances and even unconsciousness;
  • dermatitis;

Caustic alkalis MUST NOT be used with trichloroethylene or perchloroethylene as they produce an explosive mixture.

The following solvents are prohibited for use in workshops:

• petrol, kerosene, alcohol, ketones, esters;
• carbon tetrachloride

Solvent degreasing processes should not be carried out near open flames or electric heaters.

Spillages should be mopped up with rags or by absorbing in sawdust, dry sand or earth and removing to an open space. Incinerators MUST NOT be used.

Approved guidelines for solvent degreasing are given in full at the end of the document.

All degreases must have a legible copy of the relevant Material Safety Data Sheet in the location they are used in.

Electroplating and Anodising

The floor of any electroplating area should be of impervious material and chemically resistant to the substances used in the electroplating process.

Tanks must be clearly labelled " POISON " or " CORROSIVE " and show the names of the chemical constituents.

Special ventilation requirements apply to chromium and cadmium plating baths (see Section 10.5.3 in AS1485-1983).

The Waste Management Branch of the Health Department of WA should be consulted to determine any special arrangements for disposal of waste, on 222 4999.

Spray painting and Coating

All spray painting should be done in a properly constructed and mechanically ventilated booth or in the open air with a 5 metre isolation radius.

Anyone engaged in or exposed to spray painting of lead paint, silica paint or epoxy resin must wear suitable protective clothing and head covering.

The following substances are prohibited for use in spray painting operations :

• carbon bisulphide and tetrachloride
• tetrachloroethane
• arsenic or any of its compounds
• any compound containing > 1% benzene or methanol

The following substances may be used :

• amyl, methyl amyl and n-butyl acetates
• mineral turpentine
• toluene and xylene

For further information please refer to Regulations 745 to 755 of the OS&H Regs (1996) section 3.99 to 3.101.

Welding & Cutting

Many materials and coatings give off toxic fumes during welding. These include galvanised iron and compounds of cadmium, lead, zinc and many similar metals.

Inhalation of fumes can be avoided if the following precautions are observed :

• use the least toxic material or process practicable
• ensure there is adequate ventilation in the form of a movable exhaust hood or if not available then an appropriate respiratory protective device should be used.

For further information please refer to Regulations 735 to 744 of the Occupational Health Safety and Welfare Regulations 1988.