Code of Practice for Workshops (Revised October 2000)
- SUPERVISION AND CONTROL
- ACCESS TO WORKSHOPS
- WORKSHOP LAYOUT
- LIGHTING, TEMPERATURE AND VENTILATION
- NOISE AT WORK
- PERSONAL PROTECTION
- MACHINE SAFETY
- OPERATING SAFEGUARDS
- ABRASIVE WHEELS
- POWER TOOLS
- GAS CYLINDERS
- LIFTING AND LIFTING GEAR
- PRESSURE VESSELS AND COMPRESSED AIR
- PAINTING AND PAINT SPRAYING
- FLAMMABLE LIQUIDS
- SAFETY TRAINING FOR WORKSHOP STAFF
The purpose of this Code is to give guidance to all persons who have a responsibility for controlling the work undertaken in a workshop, the equipment provided and the environmental conditions under which work is performed. It is not intended as a substitute for School/Unit Rules/Codes but rather as a general source of information on the various aspects of workshop safety.
Although the Head of School/Unit is ultimately responsible for all School/Unit safety matters, members of staff also have a responsibility for aspects of health and safety within the areas under their control.
The Workshop Supervisor must satisfy himself that all machines and tools are properly and regularly maintained, cleaned and guarded. He must also ensure that the working environment and housekeeping standards are satisfactory and that any necessary safety equipment is provided and in good condition. Workshop machines by their nature can be dangerous, if not lethal, in the hands of amateurs or inexperienced operators, not only to themselves but to others in the vicinity. It is, therefore extremely important that adequate training and supervision is given to persons permitted to use the machines.
No person should be allowed to operate any machinery or tools unsupervised until they have satisfied the workshop supervisor as to their competence with that particular tool or machine.
2.4 Risk assessment
A risk assessment should be performed on all activities that pose a significant risk to human health as required by the Management of Health and Safety at Work Regulations 1999. Appropriate University forms for performing general risk assessments are available from the University safety Adviser.
The University has produced a computerised system for performing risk assessments on hazardous substances. Guidance on using this system is available from the University publication entitled ' Guidance on Chemical and Biological Safety - Part1: Chemical safety'. Copies of this guidance are available from Environmental Health and Safety Services or from their computer Web site.
All risk assessments should be made available to relevant workers.
Access to workshops should be restricted to authorised persons only. Notices to this effect should be posted on entrance doors and, wherever possible, workshops should be securely locked when left unattended. Staff are advised not to undertake hazardous work alone unless reasonable arrangements have been made to contact assistance should this be necessary.
No undergraduate should be allowed in a workshop without appropriate supervision.
No postgraduate should be allowed to work in a workshop in a manner that contradicts the basic safety regulations and the detailed School/Unit instructions as laid down by the Head of School/Unit.
3.3 Out of hours working
Any person authorised to work in a workshop during periods when the building is 'closed' must first sign the 'out-of-hours book' provided by the Head of School/Unit and sign out when he leaves the building.
4.1 Adequate spacing
Adequate spacing round machinery or plant is necessary to (i) provide access for operation; (ii) facilitate maintenance work, adjustments and cleaning and (iii) provide space for the work in progress. A minimum of one meter free space is recommended round each machine.
Gangways should be set out in such a way that the best possible access and egress is given. Obviously much depends on the area and resources available but a little forward planning and consideration of the type of work to be carried out will help make the best use of the area. Things to be taken into account when considering workshop layout are the number of operators, storage, access, lifting tackle, as well as the possible consequences of something going wrong, i.e. projectiles being thrown out of chucks or vices, broken cutters from milling machines, burst grinding wheels etc. Reference Code of Practice for Safety of Machinery (BS EN 292-1).
Fire is a major hazard in workshops that may cause death or serious injury and may cause significant damage to a workshop.
All members of staff should be informed of the procedures in the event of an fire or other type of emergency as given in the University 'Fire Action' poster. Exits must be kept clear of rubbish and other items so that they can be used in the event of an emergency.
There should be suitable numbers and appropriate types of fire extinguishers located within the workshop. All members of staff should be given instruction on the use of such fire extinguishers
Good housekeeping is a fundamental principle of accident prevention. To stumble or fall in a workshop can have serious consequences so floors must be kept free from tripping hazards, grease, oil, water or any other substance producing a slipping hazard. Swarf in particular should not be allowed to accumulate since this can penetrate hands and feet causing infection. Materials and components should be stacked correctly so that gangways are not obstructed.
Adequate lighting, permanently installed wherever possible, should be provided for machinery so that operators can see clearly the details of their work. Local lighting mounted on or within the machine should be supplied at low voltage to be completely safe.
For most bench work an intensity of 200 lux should be adequate but intensities as large as 500 lux may be required for processes involving a greater degree of skill and attention to detail.
Note: It may be dangerous to remove one tube from a twin tube fluorescent light fitting for economy since these fittings are usually designed so that the tubes are 90o out of phase. Removal of one tube may then produce a stroboscopic effect in relation to rotating machinery.
In an underheated workshop the risk of accidents is greatly increased. The temperature of a workshop should be sufficiently cool in the summer to avoid discomfort and, warm enough in winter so that the operator can work without having to wear a jacket.
The general ventilation system should effectively distribute fresh air without creating draughts. It should be capable of diluting to harmless concentration, any dust or fumes or other impurities which can arise generally in the workshop.
Toxic dusts may be produced when machining materials containing hazardous substances such as lead and mineral dusts containing a high amount of silica. In these circumstances appropriate local exhaust ventilation should be provided to ensure that safe airborne concentration limits are not exceeded. When providing such ventilation care should be taken to ensure that collecting hoods are located as close as possible to the point of dust issue.
Note: Metal and dust should never be exhausted through the same system since sparks or hot metal can ignite wood waste.
Fumes and vapours from certain materials are particularly hazardous and should not be present in the workshop atmosphere. Such materials include toluene di-isocyanate and diphenyl-methane di-isocynate which are included in the preparation of poly-urethane foams.
Another material that has vapours that should be kept to a minimum is styrene which is a constituent of unsaturated polyester resin used in glass fibre reinforcement.
School/Units which may have problems with fumes and dusts should contact the University Safety Adviser who can arrange for environmental monitoring to be carried out to determine the levels of concentration. Reference HSE Guidance Note EH22 - Ventilation of the Workplace.
The Control of Substances Hazardous to Health Regulations 1999 require all local exhaust ventilation to be tested every 14 months. The School/Unit should ensure that such testing takes place and keep the appropriate records for at least 5 years.
The Noise at Work Regulations 1989 specify three action levels (1) daily personal exposure of 85dB(A) or above; (2) daily personal exposure of 90dB(A) or above, and (3) exposure at any time to peak noise levels at or above 200 pascals. At level (1) employers must assess and record noise levels, inform employees and provide ear protection on request. At levels (2) and (3) employers must reduce noise levels where reasonably practicable, designate and signpost ear protection zones and ensure employees are provided with and instructed to wear ear protection.
Hearing loss resulting from loud industrial noise develops slowly and becomes progressively worse through continued exposure. It is this phenomenon which prevents the exposed person from being aware of the danger until it is too late.
Repeated exposure to noise may result in irreversible damage to your hearing. If you ever have to shout to make yourself heard or experience a sensation of dullness or ringing sound in the ears after work, then a noise problem probably exists.
When deciding whether continuous noise or intermittent noise is a hazard it is necessary to consider both the sound level and the number of hours of exposure per day. The following table shows the levels of noise which indicate a serious hazard to hearing.
|Personal Exposure, duration hours per day||Maximum sound level in dB(A)|
|0.25 or less||105|
If the noise levels are such that somebody cannot be clearly heard at 1 metre then it is possible the noise levels are exceeding the 'Action Levels' of the above regulations. In this situation, staff should contact the University Safety Adviser who will arrange for appropriate noise monitoring to be carried out.
Protective equipment and protective clothing should bear the CE-mark or meet the requirements of relevant governing legislation such as the COSHH Regulations.
It is sometimes difficult to identify the correct personal protective equipment (PPE) to protect against specific hazards due to the complex nature of the specifications of PPE. All PPE, therefore, should only be selected and issued by a competent person within the workshop.
All personnel issued with PPE should be given appropriate information, instruction and training in its use and maintenance.
9.1 Personal hygiene
Personal hygiene is essential to good health. Unless adequate precautions are taken staff run the risk of developing skin disorders from contact with lubricating or cutting fluids and solvents which degrease. The simplest way to avoid skin disorder is to avoid contact with such fluids and wash your hands and face frequently. Do not place oily rags in pockets or rub your hands, arms or face on contaminated clothing. The use of barrier creams can help where contact with harmful substances is unavoidable.
If any personnel are suffering from skin problems that may be associated with their work activities, then they should contact the Occupational Health Adviser as soon as reasonably practicable.
9.2 Personal clothing
There is no one recommended style of garment recognised as standard for working on machines but generally close fitting garments are the most suitable. Things to avoid are loose or torn sleeves or pockets. Ties are dangerous so either tuck them in the shirt or, preferably, do not wear them. There have been many cases of scalping due to long hair becoming entangled in rotating machinery. This can be avoided by wearing a suitable cap. Sandals have no place in a workshop where there is always the risk of heavy objects falling. Safety shoes with reinforced toe caps provide the best protection .
Safety helmets or hard hats conforming to BS EN 397 should be worn at any place where there is a risk of falling objects or restricted head room. Gloves of appropriate design and material should also be worn when handling any article with sharp edges or welding, however, they must not be worn when working with rotating machinery.
9.3 Eye protection
The protection of eyes in the working environment is a statutory requirement as specified in the Personal Protective Equipment at Work Regulations 1992. These regulations require that individuals must wear eye protection where there is a risk of injury to the eyes and, where there is an obligation upon the University as an employer to provide such protection there is an equal obligation on the employee to wear what is provided. Appropriate eye protection must be worn when performing the following tasks: welding, brazing or cutting, chipping and grinding, handling molten substances and dangerous chemicals, when using any fixed or hand held power tool which emits sparks or flying particles.
9.4 Respiratory protection
There may be occasions in the workshop when it is impractical to upgrade the ventilation in order to carry out a 'one-off' job. Such circumstances would be where there is a risk of exposure to toxic gases, fumes, vapours or dusts or where oxygen concentrations may be reduced. It is important that the correct type of respirator is worn for the particular hazard, since a mask designed to protect against dust will probably offer no protection against fumes or gases. Particular attention must be paid to choosing the correct mask when machining any metal producing toxic dust. Under the Control of Substances Hazardous to Health Regulations 1999 a risk assessment must be completed before commencing work with hazardous substances - see University publication entitled 'Guidance on Chemical and Biological Safety part 1: Chemical Safety'.
Advice on the selection of suitable respiratory protection and on the proper use can be obtained from the University Safety Adviser. See also HSE Guidance Note HS(G)53 Respiratory Protection Equipment - The Selection, Use and Maintenance of Respiratory Protective Equipment.
9.5 Noise protection
Where possible, reduction of noise levels should be achieved by enclosing the source in sound dampening panels. It is only when this is not practicable that personal hearing protectors should be provided. This can either be in the form of ear plugs or ear muffs. It is important that ear plugs are of an approved type and that users are instructed on the correct method of insertion. In any area where the noise level exceeds 85 dB(A) appropriate warning signs must be displayed on the entrance door.
Where noise levels exceed 85 db(A) over an 8 hour work period but less than 90 dB(A), then ear protection must be provided by the School/Unit but workers do not have to wear it. Where noise levels exceed 90 dB(A) over an 8 hour work period or the peak noise levels are greater than 200 Pascals, then the School/Unit must provide appropriate ear protection and workers must wear the ear protection.
If the noise levels are such that somebody cannot be clearly heard at 1 metre then it is possible the noise levels are exceeding the 'Action Levels' of the above regulations. In this situation, staff should contact the University Safety Adviser who will arrange for appropriate noise monitoring to be carried out.
10.1 Provision and use of work equipment regulations
The variety of machines currently in use precludes detailed consideration in this handbook. All workers should be conversant with the Provision and Use of Work Equipment Regulations 1998 (Reference: Approved Code of Practice - Provision and Use of Work Equipment Regulations 1998).
In addition it is University policy that all machinery whether fixed or portable shall be fitted with appropriate safeguards at least to the standard required by BS EN 292-1.
10.2 Dangers from machinery
A person may be injured at machinery as a result of,
- coming into contact with it, or being trapped between machinery and any material in or at the machinery or fixed structure;
- being struck by, or becoming entangled in or by, any material in motion in the machinery;
- being struck by parts of the machinery ejected from it; and
- being struck by material ejected from the machinery.
These may be regarded as mechanical hazards. Some machinery may also present non-mechanical hazards in which the dangers are less obvious or tangible e.g. electricity, noise, hazardous substances etc. .
10.3 Principles of safeguarding
The basic principle is that, unless a danger point or area is safe by virtue of its position, the machinery should be provided with an appropriate safeguard which eliminates or reduces danger before access to the danger point or area can be achieved.
Note: It is emphasised that the absence of any injury from operating machinery without the necessary safeguards over a period of time does not mean that the moving parts of the machinery are not dangerous.
10.4 Types of safeguards
10.4.1. A fixed guard should be used wherever practicable. The guard should, by its design, prevent access to the dangerous parts of the machinery. It should be of robust construction, sufficient to withstand the stresses of the process and environmental conditions. It should be securely fixed in position when the machinery is in motion, or is likely to be in motion.
Where it is necessary for work to be fed through the guard, openings should be sufficient to allow the passage of material only and should not allow the operator access to the danger point.
10.4.2. Interlocking guards
When a process demands access to a danger area and a fixed guard is impracticable, the provision of an interlocking guard should be considered. An interlocking guard should be so connected to the machine controls that,
(i) until the guard is closed the machine cannot be operated; and
(ii) either the guard remains locked closed until the dangerous
movement has ceased, or, where overrun is sufficient to create danger, opening the guard disengages the drive.
10.4.3. Adjustable guards
Where it is impracticable to prevent access to dangerous parts because they are unavoidably exposed during use (e.g the cutter on a mill machine, the blade on a circular saw, band saw or the chuck on a drilling machine) the use of an adjustable guard may be permitted. An adjustable guard provides for an opening to the machinery through which materials can be fed, the whole guard or part of it being capable of adjustment in order that the opening can be varied in height or width to suit the dimensions of the work in hand.
It is essential in such cases that the adjustment is carefully carried out for each task so that openings are sufficient only to allow the passage of material. Adjustable guards should be so designed that the adjustable parts cannot easily become detached and mislaid.
10.4.4. Distance guard
A distance guard operates by physically removing from the danger area any part of a person exposed to the danger. Such guards are suitable for power presses and guillotines.
10.4.5. Automatic sensing and tripping devices
Photo-electric devices can be used to isolate the machine drive when a person is detected within the danger zone. Other types of automatic guards include trip devices which, when touched, activate a switch cutting off the power supply and applying a brake. A trip device fitted in close proximity to the chuck on a radial drill can be used to isolate the power supply and activate a brake when deflected. A pressure sensitive mat may be used to isolate the power supply and activate a brake when deflected. A pressure sensitive mat may be appropriate in circumstances where the use of a fixed guard or an interlock guard is impracticable. The machinery cannot be set in motion until the operator and any other persons in the vicinity are standing clear of the mat which protects the danger area.
10.4.6. Emergency power stop buttons
In addition to mechanical safeguards, emergency power stop buttons should be located at strategic points throughout the workshop. Such devices should be of the non-self-resetting type.
10.4.7. Machine maintenance
Whenever maintenance is taking place on a machine the greatest care must be taken to ensure that the machine is completely isolated electrically against any possibility of inadvertent start-up or electrical shock before any work on the machine is undertaken. Power fuses should be removed and a notice attached to the supply warning not to switch the power on. Reference BS EN 292-1.
11.1 Before starting any machine it is essential that the functions of the machine and its method of operation are thoroughly understood, that the machine is suitable for the purposes intended and that it is safe to use.
11.2 The following precautions should be checked before starting up:
11.2.1. ensure that the proposed job is within the capacity of the machine;
11.2.2. ensure that the machine is in good operating order;
11.2.3. ensure that any cutting tools used are properly sharpened;
11.2.4. ensure that the workpiece is securely clamped and correctly located;
11.2.5. ensure that all guards are securely in place and properly adjusted and that, where provided, dust or exhaust extraction systems are functioning correctly;
11.2.6. ensure that where coolant is used the flow is adequate and properly adjusted;
11.3. The following practices are unsafe and should not be permitted:
11.3.1. attempting to clean a machine whilst it is in motion;
11.3.2. attempting to remove swarf near a revolving spindle;
11.3.3. removing swarf with bare hands;
11.3.4. reaching across a machine spindle when it is running;
11.3.5. attempt to free a jam from a machine whilst it is running;
11.3.6. attempt to gauge a workpiece whilst it is revolving;
11.3.7. leaving a machine unattended whilst operating.
There are four main hazards associated with the use of abrasive wheels the most serious of these being the bursting of a wheel. Bursting, i.e. the explosion of a wheel whilst in motion, can happen as a result of the wheel being used at an incorrect speed, faulty mounting, or operator misuse. The more common accidents are caused as a result of personal contact with the wheel, by particles flying from the wheel into the operator's eyes or face and by fragments of the wheel flying off and hitting the operator. The use and maintenance of abrasive wheels is now regulated by the Provision and Use of Work Equipment Regulations 1998.
12.1 Mounting and Dressing
Abrasive wheels must be properly mounted/dressed and the people who carry out such work to be adequately trained and officially appointed. A wheel should not be mounted on a machine for which it is not intended.
All wheels have to be provided with guards which must be in position whilst the wheel is in motion. Guards should not only prevent the operator from touching the wheel in motion but also ensure the operator is protected from anything thrown from the wheel.
A wheel's soundness can be tested by tapping it gently. If it rings it is sound, if the sound is dull then the wheel is suspect and should be carefully examined. Work rests should be adjusted as close as possible to the wheel to prevent the workpiece jamming between the wheel and the rest. The minimum distance should be no greater than 2 m.m.
Means of stopping the machine should be within easy reach of the operator and before changing a wheel the power supply should be isolated. For further information reference should be made to HSE Guidance Note PM22 (Mounting of Abrasive Wheels).
13.1 Hand held power tools have been the cause of many fatal accidents and are potentially more dangerous that static machinery.
Most power tools have some form of cutter, abrasive disc or drill which is difficult to guard totally and consequently they should only be used by skilled authorised persons. In all instances suitable eye protection must be worn.
13.2 Before use, both the tool and power cable should be examined for defects and any fault repaired. Check the entire length of the cable for cuts or wear on the outer sheath. DO NOT wrap a defect with insulating tape if the cable is damaged; replace the entire cable. JOINTS in flexible cables are ILLEGAL. Tools which cannot be repaired immediately should be labelled as faulty and stored in a secure place.
13.3 Only properly earthed or certified double-insulted power tools should be used. Such equipment should be maintained in accordance with the manufacturers recommendations and regularly inspected. Records of such work should be kept.
13.4 If using an enclosed reel extension cable it should be fully unwound as heat has been known to melt the insulation in a partially unwound reel carrying a heavy current.
Reference HSE Guidance Note PM32 Safe Use of Portable Electrical Apparatus.
14.1 There are two main hazards arising from the use of electricity : electric shock and fire. The major cause of accidents can be attributed to unauthorised interference with power supplies and electrical equipment.
Under the Electricity at Work Regulations 1989 no person shall be engaged on any work activity involving the construction, modification, repair or maintenance of electrical equipment and associated electrical connections unless they are deemed to be competent to undertake such work or are under suitable competent supervision. In addition all fixed and portable equipment and the connections to each equipment are required to be inspected and tested at specified intervals and the results recorded - see University Guidance Notes on the Inspection and Testing of Portable Electrical Equipment.
A University booklet entitled "University Local Rules for Electrical Safety" has been produced on general electrical safety and the Electricity at Work Regulations - copies of both are available from the Safety Office.
Welding involved equipment that can lead to serious injuries if it is mis-used. The main dangers from welding processes are fire, explosion, fumes, burns, radiation and electric shock.
The main health hazards are:-
- exposure of the skin to infra-red and ultra-violet radiation resulting in irritation and burning as in sunburn. If severe enough this may produce dermatitis.
- 'Arc Eye', due to the exposure to ultra-violet rays, is a superficial burn to the outer cell layer of the eye. In most welders the effects are probably more often due to the accumulated effects of several flashes during a spell of work. The condition rapidly improves and the eye returns to normal in a day or two without permanent injury.
- 'Metal Fume Fever', one of the commonest hazards in welding, is due to the harmful action on the lining of the respiratory tract by freshly formed oxides of various metals i.e. zinc, cadmium etc. After exposure to the fume there is usually a delay period of a few hours before the person begins to feel ill. The symptoms are similar to a severe bout of influenza and usually disappear after a day or two.
Anyone suffering from any of the above symptoms, then they should contact the Occupational Health Adviser for advice.
All types of welding produce some degree of toxic fumes and effective extraction ventilation is essential to prevent the accumulation of fumes, smoke and dust. Ventilation becomes a critical factor in preventing oxygen deficiency during heavy or long periods of welding. If suitable extraction ventilation is not available and the work is to be undertaken in a confined space a COSHH risk assessment must be completed before the work commences.
15.3. Protective clothing
The wearing of heat-resistant gloves is common sense and essential to prevent burns from the work piece, sparks and hot metal. A heat and fire resistant apron should also be worn to protect clothing and prevent sparks or hot metal becoming trapped in pockets. Rolled up sleeves and trouser turn-ups should not be allowed for the same reason. The wearing of nylon overalls should not be permitted during welding.
15.4 Eye protection
Suitable eye protection or face shields are essential for welding and cutting operations. Goggles should be used for gas welding and a face shield for arc welding. The arc must never be struck without the face shield in position since intense ultra-violet and infra-red rays are generated. Persons assisting with a welding operation must also wear suitable eye protection. Failure to take these precautions may result in part or total blindness.
It is also essential to consider the safety of others in the vicinity of welding operations and fire resistant screens should be positioned so that the welding operation cannot be viewed by others.
15.5 General note
When welding, the work piece should never be placed on a concrete floor or on certain types of asbestos sheet, as these materials can explode forcibly on heating by flame or arc.
When welding tubular or box structures, care must be taken to avoid air being trapped so completely that a "blow-out" of molten metal occurs. A standard practice is to drill a tiny hole somewhere convenient in the job to allow air to escape, and then, if necessary, to weld over the tiny hole finally when the workpiece has cooled off.
15.6 Safety in oxyacetylene welding
Oxygen and acetylene cylinders, because of the high pressures of the gases they contain, necessitate special care in storage, handling and installation.
The oxygen cylinder usually contains a higher pressure than the acetylene cylinder. Acetylene cylinder fittings are left-handed.
Oxygen and acetylene cylinders should be stored vertically and in chained racks. Where large numbers of oxygen and acetylene cylinders are stored, regulations specify how they must be stored. Since the majority of welding operations require only one oxygen and one acetylene cylinder it is safer to have only the two required cylinders in the work area, and keep all spare cylinders in storage until required. Cylinders must be transported on proper trolleys and not "rolled" to the work area.
Examine each cylinder before installing for use and, if any defect is detected, reject immediately and return to the supplier. The cylinder must be installed and used vertically, chained to wall racks or secured in welding trolleys. Flash back arrestors to the most recent British Standard Specification must be used in both oxygen and acetylene lines to prevent fire or explosion by "blow-backs" rupturing regulator diaphragms. It is preferable to have each gas hose of the same equal length, taped or clipped together to prevent hose loops catching on any protruding objects.
When cracking open "snifting" cylinders prior to installing the regulators (as is standard practice to clear the gas cylinder outlets of dust and dirt) ensure that the cylinder is chained vertically, that nothing is in the way of the gas jet and that no naked flames are in the vicinity.
Note: Never "snift" hydrogen as it may ignite spontaneously and never "snift" toxic gases. Any dirt may be blown out with a jet of clean compressed air or nitrogen
The hoses and regulators must be in first-class condition. If not, replace immediately. Welding nozzles should be kept clean and the threads of the nozzles (if threaded types are used) must be undamaged and screw freely into the gun to procure a tight seal. The welding gun should also be in first-class condition and checked periodically for leakage (using soapy water solution) at valves, hose connections and body joints if they exist.
The valve keys must be kept in position on each cylinder valve, so that in the event of a malfunction in the cylinders, can be shut off.
The flame should only be ignited by flint gun or "striker" and never by naked flame or match. Lighting by match can result in severe finger burns. Cigarette lighters should not be used for the same reason.
Note: Oxygen equipment must be kept free from oil or grease, as oxygen in contact with these can result in a violent explosion. For the same reason it is preferable to keep welding gas equipment well away from electrical plugs, sockets and switches.
When testing for suspected leaks, naked flames must not be used. Use a purpose designed commercial product or a soapy water solution (a few drops of detergent in water) to detect leaks.
The acetylene cylinder requires a few special considerations for safe usage. It usually contains a quantity of acetone in which the acetylene is dissolved and if an attempt is made to use the cylinder in the horizontal position, the acetone can leak into the regulator, gauges and hoses.
Free acetylene gas must never be stored at pressure above 15 p.s.i. Above this pressure it is extremely unstable and may explode.
Acetylene gas must never be allowed to come in contact with unalloyed copper (eg copper tubing) with the exception of the welding torch nozzle. Copper acetylene will form which is an extremely reactive chemical which can explode violently.
When shutting down the gas supply, first close off the acetylene at the touch control valve then the oxygen. Close the supply valves on the cylinders, then open and close the torch control valves (oxygen first then acetylene) one at a time to relieve pressure in the system ensuring the gauges register zero.
Note: Acetylene is a highly flammable and explosive gas (Reference: BOC Gas Welding Handbook and the Health and Safety Executive 20 Point Guidance Code - Use of Compressed Acetylene).
15.7 Safety in electric arc welding
Electric arc welding need not be a hazardous process if prescribed precautions are followed, such as have been detailed in sections 13.0 to 13.5.
There is, however, always the possibility of electrical shock. Therefore it is necessary that all cables, electrode-holder insulation, earthing clamp and electrical mains wiring is maintained to a high standard and defect free. The earthing of the welding control cabinet must be checked on a regular basis. Stray currents can cause severe shock.
Arc welding should not be carried out on damp or wet floors. Hands and clothing should be kept dry.
Care must be taken to avoid allowing the uninsulated part of the electrode holder coming in contact with the "earthed" job or the earthing clamp while the current is on. The flash produced is extremely dangerous to the eyes.
The arc must never be "struck" without the face-shield being in its protective position and must be kept in the protective position until the arc extinguishes. Even momentary flashes are extremely dangerous to the eyes. (Reference HSE Guidance Note PM64 Electrical Safety in Arc Welding and HS(G)204 - Health and Safety in Arc Welding).
15.8 Safety in brazing (with gas equipment)
Protective gloves must be worn to prevent hand burns, except perhaps on very small work, but protective gas welding goggles must be worn for all classes of brazing, except for silver soldering where clear glass goggles should be used.
Suitable tongs must be available for handling "pre-heated" work and the work in hand must be in good condition.
Fume extraction is absolutely essential as most brazing rods contain percentages of zinc, phosphorous, copper, etc., all of which when heated produce highly poisonous fumes. In addition, many brazing fluxes are corrosive and toxic fume-producing. The corrosive fluxes are usually removed when brazing is completed. Suitable gloves must be worn for the washing operation to avoid skin complaints and the eyes protected from splashing by wearing clear-glass goggles.
Silver soldering may be considered a brazing process. Many of the proprietary low melting point silver solders contain cadmium which is an extremely toxic fume-producer and on no account should these fumes be breathed in during a silver-soldering operation. Again efficient fume extraction is essential.
In instances where suitable extraction ventilation is not available a COSHH risk assessment must be completed before the work commences.
As with most other pieces of workshop equipment, compressed gas cylinders are safe if treated in accordance with the manufacturer's instructions. However, when handled incorrectly or accidentally damaged they can be extremely dangerous releasing large quantities of toxic or flammable gases. If the main valve is damaged the cylinder can become jet propelled by a pressure of up to 2500 p.s.i.
Only those cylinders of compressed gases actually in use should be kept within a building. Such cylinders should be securely supported in an upright position either on a cylinder trolley/stand or by a retaining chain or bench strap. External cylinder stores are provided at most locations and full use should be made of these facilities. For transporting cylinders properly designed trolleys capable of carrying cylinders should be used.
16.1 Colour coding
Gas cylinders are painted different colours according to the gas contained and charts are available from the suppliers identifying the various gases. Safety data sheets on gases are available from BOC.
Cylinders must never be used without a pressure reducing regulator. Modern regulators are designated for particular gases and are not interchangeable. Cylinder valve outlets are screwed left-handed for combustible and right-handed for non-combustible gases.
Regulators and their associated pressure gauges should never be tampered with. If they leak or the pressure gauge is suspect the regulator should be sent back to the manufacturer for repair. In the case of fuel gases the use of flashback arrestors is strongly recommended where sources of ignition exist.
Regulators should be serviced every 5 years to ensure they are safe.
16.3 Cylinder connections
Cylinder valves must be kept free of oil, water or other foreign matter. Always open a valve slowly and when closing do not use excessive force. Rubber, or other appropriate reinforced tubing of the correct thickness, must be used to withstand the operating pressures. Tubing must be in good condition and kept clear of possible damage by cuts, cracks or heat.
Suspected leakages should be tested with soapy water and brush. If a leak is detected the cylinder should be placed in the open air well clear of any building or source of ignition and the supplier informed to uplift.
Oxygen is odourless and whilst it does not burn it accelerates combustion so never allow your clothing to become saturated with oxygen. Oil or grease will ignite violently in the presence of oxygen which, if under pressure, can cause an explosion. Oxygen must never be used in place of compressed air.
For further information reference should be made to the booklet 'Safety Under Pressure' - Guidelines for all who use B.O.C. gasses in cylinders.
17.1 Manual lifting is the cause of many industrial injuries ranging from back strain to ruptures.
Note: No member of staff should attempt to lift or move a load if they are in any doubt as to their capability to do so without risk to their health and safety.
To avoid injury first assess the size, shape, weight and centre of gravity of the load and determine whether help is required. If in doubt, use a mechanical hoist. If the load can be handled manually:-
17.1.1 wear gloves, especially if the load is rough or has sharp edges;
17.1.2 position your feet correctly. They should be slightly apart to maintain good balance, but not too wide or there will be danger of strain or rupture;
17.1.3 stand so that the arms are close to the body;
17.1.4 do not bend the back to lift the load but bend the knees instead;
17.1.5 do not rely on the fingers alone to grip the load but take a firm hold with the palms;
17.1.6 keep the back straight even though it may be inclined slightly from the vertical and look straight ahead;
17.1.7 use the power of the legs and knees to perform and lift and rise smoothly and surely. A video and booklet giving advice on Manual Handling are available from the Safety Office.
17.2 Mechanical lifting appliances should only be used by suitably trained persons. All lifting tackle in the University must be registered with Estates and Buildings who ensure that statutory inspections and tests are carried out annually. Lifting equipment should be visually inspected before use and checked to verify that it is strong enough for the load to be lifted. Great care should be taken in locating the slings so that the load remains secure when suspended. Never stand under a suspended load. All persons involved in the use of lifting tackle must wear safety shoes and a suitable helmet if the load is to be raised above head height. Operators of power lift trucks must have attended an approved course of instruction and obtained a 'Certificate of Competence'. (Reference: Approved Code of Practice, Lifting Operations and Lifting Equipment Regulations 1998,).
18.1 The Pressure Equipment Regulations 1999 impose safety requirements on the design and construction of pressure equipment. The Pressure Systems Safety Regulations 2000 impose safety requirements on the installation, repair, modification and use of pressure systems. A key element of the Pressure Systems Safety Regulations is the need for a written scheme to be drawn up by a competent person specifying the extent and frequency of inspections. Specialist contractors have been employed to undertake this work and it is essential that all School/Unit pressure systems are notified to Estates & Buildings to ensure that they are put on the register for annual inspection. Safe operating limits must be displayed on all vessels. University constructed pressure vessels must conform to the appropriate British Standard and by subject to inspection and approval by the University's Insurers before being brought into use.
Transportable gas cylinders and research systems operating below 0.5 bar (9 p.s.i.) or where the volume of the largest vessel is less than 250 bar/litres, are exempt from some of the Regulations.
Welding plant which is fuelled by transportable gas cylinders should be checked at regular intervals to verify that it is in a safe condition (BOC's checklist is recommended). A written record should be kept of all such checks.
18.2 Compressed Air Compressed air is potentially one of the most lethal hazards in the workshop. A small jet directed into the eyes, ears or nose can cause death or serious injury. If air is allowed to enter a scratch or other puncture of the skin painful swelling can result. If air is allowed into the blood stream the result can be fatal. Compressed air should always be handled with care and never used to remove dust etc. from clothing. Safety glasses should be worn to protect against blown particles.
19.1 Paint spraying carries with it both a toxic and fire hazard and must, therefore, be carried out in a well ventilated enclosure. The vapours
evolved from certain paints can contain up to 80% volatile solvents which must be ventilated to enable drying to take place. If these vapours are allowed to accumulate serious explosive conditions can develop.
Serious health hazards are associated with two-pack polyurethane paints and lacquers in which the hardener contains small amounts of active iso-cyanate. When spraying such paint a positive pressure compressed air mask must be worn.
Certain iso-cyanates are know to be allergens and thus may cause allergic responses in certain individuals. If any employee suffers one or all of the following signs:
- Itchy eyes;
- Sneezing, running or blocked nose;
- Chest tightness with wheezing;
- Itchy skin rash;
- Swelling of lips, sometimes swelling of the tongue as well
then they should contact the Occupational Health Adviser as soon as practicable.
The spraying of epoxy based paints and undercoats can present a skin-contact hazard leading to irritation or rashes. Protective clothing and a suitable respirator should be worn to prevent contact with mist spray.
19.2 Painting in enclosed areas can create a build-up of toxic vapour alarmingly fast. Detailed advice on the precautions to be taken when working in an enclosed area can be found in the HSE Guidance Note GS5.
In all instances where hazardous fumes are given off, a COSHH risk assessment must be completed before the work commences.
Asbestos fibres can cause many serious diseases including lung cancer and mesothelioma cancers.
The Asbestos (Prohibitions) Regulations 1992 and the Asbestos (Prohibitions) (Amendment) Regulations 1999, prohibit the importation and supply of items containing asbestos. There are certain exemptions from these regulations and these are available from the University Safety Adviser on request.
To ensure compliance with the Control of Asbestos at Work Regulations 1987, only Health and Safety Executive 'Licensed Contractors' may perform work that generates asbestos fibres in the air within the University. Any item that is thought to contain asbestos should not be worked on until it can be confirmed that it does not contain asbestos. If there is any doubt as to the composition of any material, analysis for asbestos can be arranged through the Safety Office.
21.1 Vapours from highly flammable liquids (i.e. liquids with a flash point less than 32oC) present a serious fire and explosion hazard since they are easily ignited, difficult to extinguish and burn vigorously. It is clearly desirable that stocks of high flammable liquids held in workshops for ready use should be kept at the lowest practical level. Safe storage of flammable liquids can be provided by keeping them in properly constructed fire-proof cabinets. However, the maximum quantity that may be kept in any one room must not exceed 50 litres. Bulk quantities in excess of 50 litres must be kept in a properly constructed fireproof store.
21.2 All stores and containers of highly flammable liquids should be marked HIGHLY FLAMMABLE and a NO SMOKING notice also displayed. Reference: HSE Leaflet - Storage and the use of Highly Flammable Liquids in Educational Establishments and HSE Booklet - The Storage of Flammable Liquids in Containers HS(G)51.
Contact with resins should be avoided where possible as they can cause skin irritation which may lead to dermatitis. In sufficient concentrations resin vapour is toxic and highly irritating to the eyes and respiratory passages. Vapours are heavier than air and will remain at low level.
The handling of unpolymerised resin should be carried out in a fume cupboard. Polymerisation of resin blocks should be done in an oven vented to the open air or in a small oven located inside a fume cupboard.
Potential hazards also arise from dust produced by sawing or filing. During such work respiratory protection should be worn and all traces of dust removed by vacuum. Smoking, eating and drinking should be prohibited in areas where resins are handled.
A COSHH risk assessment must be completed before work with resins is undertaken.
Many types of dusts are known to be hazardous to health e.g. hardwood dusts. It is, therefore, very important to ensure that the level of dusts within a workshop are kept to a minimum. This is achieved by using local exhaust ventilation at the work site. The level of dust can also be reduced by good housekeeping procedures that regularly remove dust from the workplace.
In areas of high dust production e.g. a woodworking workshop, regular monitoring of dust levels should be performed. The University Safety Adviser can arrange for such monitoring to be performed.
As dusts are hazardous substances, a COSHH risk assessment should be performed in areas that pose a significant risk to health. The assessments should be made available to all relevant staff. It may be necessary to issue appropriate respiratory protective equipment in work areas with high dust levels that cannot be controlled by any other means (the issuing of PPE should always be considered a last resort when all other means are not practicable). In this situation care should be taken to issue the correct respiratory protective equipment and to ensure that appropriate information, instruction and training in the use and maintenance of the equipment is given to all relevant staff.
The COSHH regulations require the School/Unit to ensure that local exhaust ventilation is inspected and tested every 14 months. Records of such inspections must be kept for at least 5 years.
It is University policy to provide such information, instruction, training and supervision as is necessary to ensure, so far as is reasonably practicable, the health and safety at work of its employees.
Employees in turn also have a duty to take reasonable care for the health and safety of themselves and of others who may be affected by their acts or omissions. In addition, employees have a legal obligation to co-operate with an employer in compliance with safety legislation
Due to the hazardous nature of workshop environments it is essential that persons working in such areas have a responsible attitude and be capable of working safely. To achieve this end workshop staff should therefore:-
- recognise the need for caution in workshops and be aware of possible causes and sources of danger in a work place;
- be aware of personal hygiene, recognising dangers associated with scratches, cuts, burns and understand the hazards of eating and smoking in workshops;
- be able to identify and use various types of protective clothing and equipment - coats, aprons, safety glasses/goggles, face shields, masks, respirators, gloves, shoes and helmets - to describe the functions of various protective aids and to recognise the situations when such items are required to be used;
- be aware of the regulations covering the labelling of dangerous substances and be able to identify the relevant hazard symbols;
- be aware of the regulations and safeguards regarding the use and storage of flammable liquids;
- be aware of the common toxic and carcinogenic substances which he/she may come in contact with and the way such substances can enter the body and the need for a COSHH Risk Assessment to be completed before working with hazardous substances.
- understand the precautions that should be taken when handling such substances and be aware of the additional risks to pregnant women;
- be aware of the safe methods of disposable of waste material and that flammable waste materials should be kept in appropriate purpose built containers;
- know the equipment which assists in the safe transport of goods, chemicals, bottled gases, etc.;
- be aware of the correct methods of lifting heavy articles;
- know the basic rules for the storage, handling and use of compressed gas cylinders;
- be aware of the general importance of ventilation and the need to maintain adequate air flow;
- know the British Standard colour code for both mains and flexible power leads.
- recognise the implications of colour blindness;
- know how a main plug top is correctly connected to a flexible lead and be able to select the appropriate fuse for the equipment;
- understand the reason for earthing a metal clad appliance and be able to demonstrate how a piece of equipment may be earthed;
- know that some double insulated equipment is not provided with earthing connection;
- recognise and eliminate the hazards associated with electrical usage, e.g. careless routing of flex, broken plugs and sockets, worn and badly joined leads, overloading supplies, careless use of multiple adaptors and distribution boards;
- understand the use of fail safe and limiting switches on appliances;
- know the inherent dangers and hazards when using portable power driven tools, e.g. hand drills, sanders, saws, etc. the precautions to be taken when handling such equipment;
- appreciate the simple physiological consequences of the passage of an alectric current through the body and understand the action to be taken in the event of electric shock;
- be aware of the regulations covering the use of machine tools, e.g. abrasive wheels, vertical drills, lathes, power presses;
- know the function and location of automatic tripping devices and emergency stop buttons;
- be aware of the hazards of handling metal swarf;
- appreciate the hazards of long hair and loose clothing when working with machine tools;
- be aware of and comply with the regulations covering the protection of eyes;
- appreciate the hazards of working with materials giving off dust, and know the respiratory precautions to be taken;
- understand the hazards arising from welding and brazing particularly in respect of the use of oxy-acetylene equipment and the possible emission of toxic fumes;
- be aware of the function and need for flash-back arrestors to be fitted to flammable gas cylinders;
- know the regulations governing the use of acetylene gas at pressure of more than 9 psi;
- be aware of the glare from arc welding and the possibility of 'arc eye' injuries;
- appreciate the operational principles for cranes, slings, pulleys and other lifting tackle, the limits to their use and the need for regular maintenance and examination;
- appreciate the need for ear protection where sound levels are in excess of 85 dB(A) for prolonged periods;
- know that oil mist from certain cutting oils can present a cancer risk in addition to dermatitis;
- be aware that nitrogen oxides can build up in glassblowing workshops when oxygen and natural gas flames are used;
- be familiar with and able to use the appropriate fire extinguisher to deal with each class of fire;
- recognise situations which can lead to fire and the importance of constant vigilance;
- know the location of extinguishers, fire alarm points and the action to be taken in the event of a fire, i.e. sounding the alarm, notification of fire brigade, evacuation and assembly;
- recognise the implications for deaf or disabled persons during fire alarms;
- know where first-aid boxes are located, names and locations of trained first-aiders and the procedure for summoning medical aid and reporting accidents.