SCHOOL OF ENGINEERING
WORKSHOP
SUPPLEMENTARY SAFETY INFORMATION
AUGUST 2014
TO BE READ IN CONJUNCTION WITH SCHOOL SAFETY HANDBOOK
Senior Technician, Electronics
Mr D. Logan
Tel: 4384
Senior Technician, Mechanical
Mr A. Robertson
Tel: 2533
Technical Resource Officer (TRO)
Mr G. Cordiner
Tel. 2788
Contents
1. CODES OF PRACTICE FOR MECHANICAL WORKSHOP ................................................................. 1
1.1 The Machine Shop ................................................................................................................. 1
1.1.1 Dangers From Machinery ............................................................................................... 1
1.1.2 Precautions ..................................................................................................................... 1
1.1.3 The Machine ................................................................................................................... 1
1.1.4 The CNC Milling Machine ............................................................................................... 2
1.1.5 The CNC Lathe ................................................................................................................ 3
1.1.6 The Work Piece ............................................................................................................... 4
1.1.6 The Work Area ................................................................................................................ 4
1.1.7 Procedures...................................................................................................................... 5
1.2 Cylindrical And Surface Grinders ........................................................................................... 5
1.2.1 Wheel RPM ..................................................................................................................... 6
1.2.2 Magnetic Chuck .............................................................................................................. 6
1.3 Machine Maintenance – Disconnection From Power Source ............................................... 6
1.4 The Welding Fabrication and Fitting Shop ............................................................................ 7
1.4.1 General Safety ................................................................................................................ 7
1.4.2 Welding Brazing and Fitting............................................................................................ 8
1.4.3 Fabrication and Fitting.................................................................................................. 11
1.4.4 Lifting and Lifting Equipment ....................................................................................... 13
1.4.5 Storage and Handling of Materials ............................................................................... 13
1.4.6 Painting and Spray Painting .......................................................................................... 14
1.5 The Woodworking Shop ...................................................................................................... 15
1.5.1 Training ......................................................................................................................... 15
2. CODES OF PRACTICE FOR ELECTRICAL/ELECTRONIC WORKSHOP ............................................ 17
2.1 Electricity ............................................................................................................................. 17
2.1.1 Electric Shock ................................................................................................................ 17
2.1.2 Treatment for electric shock ........................................................................................ 17
2.1.3 Burns ............................................................................................................................. 18
2.1.4 Radiation induced injuries ............................................................................................ 18
2.2 Buildings and Supplies ......................................................................................................... 19
2.3 Hazardous Areas .................................................................................................................. 19
2.3.1 Wet area - Field work, greenhouses, aquariums and animal houses.......................... 19
2.3.2 Cold Rooms ................................................................................................................... 20
2.3.3 Areas with flammable or explosive atmospheres ........................................................ 20
2.4 Isolation From Mains And Protective Devices ..................................................................... 20
2.4.1 Isolation ........................................................................................................................ 20
2.4.2 Transformers and low voltage supplies........................................................................ 20
2.4.3 Batteries ....................................................................................................................... 21
2.4.4 RCD Protected Outlets, Adapters and Other Protective Devices ................................. 21
2.5 Medical Equipment ............................................................................................................. 21
2.6 Workshop Practices ............................................................................................................. 22
2.7 Live Working ........................................................................................................................ 23
2.7.1 High Current Supplies ................................................................................................... 23
2.7.2 High Voltage (650-3KV) and Extra-High Voltage (>3KV) Supplies ................................ 23
2.7.3 Medium Voltage Supplies (250-650V) .......................................................................... 24
2.7.4 Low Voltage Supplies (50-250V) ................................................................................... 24
2.7.5 Trainees and other Persons with Limited Skills or Experience ..................................... 24
2.7.6 Place of Working........................................................................................................... 24
2.7.7 Equipment .................................................................................................................... 24
2.7.8 Precautions ................................................................................................................... 24
2.8 Non-Live Working (Permanently Connected Mains Connections) ...................................... 26
2.8.1 Precautions ................................................................................................................... 26
2.9 Working Within the Workshop............................................................................................ 26
2.9.1 Precautions ................................................................................................................... 26
2.10 Lasers ................................................................................................................................. 27
2.11 Further Reading ................................................................................................................. 27
2.12 Definitions ......................................................................................................................... 27
3. WORKING OUTWITH THE WORKSHOP ..................................................................................... 29
3.1 Precautions .......................................................................................................................... 29
4. APPENDICES ............................................................................................................................... 30
4.1 Chemicals In the Workshop ................................................................................................. 30
4.1.1 Introduction .................................................................................................................. 30
4.1.2 Cleaning And Degreasing .............................................................................................. 30
4.1.3. Metalworking Fluids .................................................................................................... 31
4.1.4 Decanted Chemicals .................................................................................................... 32
4.1.5 Printed Circuit Board Chemicals .................................................................................. 32
4.2 Chemical Datasheets ........................................................................................................... 33
4.2.1 Acetone ........................................................................................................................ 33
4.2.2 Ethanol, Methanol And Propanol (Ethyl, Methyl And Isopropyl Alcohol).................... 34
4.2.3 Paraffin (Kerosine) ........................................................................................................ 35
4.2.4 White Spirits ................................................................................................................. 36
4.2.5 Printed Circuit Board Chemical Developer Solution: Sodium Metasilicate .................. 37
4.2.6 Printed Circuit Board Chemical Stripper: Monoethanolamin 25%, Butoxyethanol 65%
............................................................................................................................................... 38
4.2.7 Printed Circuit Board Chemical - Ferric Chloride Hexahydrate Crystals....................... 39
4.2.8 Printed Circuit Board Chemical PC168 Immerse Tin: Thiourea 27%, Stannous Chloride
15% ........................................................................................................................................ 40
1. CODES OF PRACTICE FOR MECHANICAL WORKSHOP
The Mechanical Workshop from the safety point of view can be divided into four
separate areas i.e.
 The Machine shop (general)
 Grinding Machines
 The Welding fabrication and fitting shop
 The Woodworking shop
1.1 The Machine Shop
The main type of machines that are to be found in the machine shop are lathes, milling
machines, drilling machines and grinding machines. These machines are all manually
operated in as much as they require the constant attention of highly skilled operator/setter
for normal operation. These machines require constant adjustments and alterations
during their operation and so therefore safety consciousness and vigilance are of
paramount importance.
1.1.1 Dangers From Machinery
A person may be injured at machinery as a result of:
 coming into contact with it, or being trapped between the machinery and any
material in or at the machinery or any fixed structure.
 being struck by, or becoming entangled in or by, any material in motion in the
machinery.
 being struck by fragments of cutting tools ejected form it.
 being struck by material ejected from the machinery.
1.1.2 Precautions
Precautions can be divided into 4 categories, these are:
 The Machine
 The Work piece
 The Work area
 Procedures
1.1.3 The Machine
 It is the responsibility of each authorised operator (see list of authorised operators
displayed on the Health and Safety notice board) to see that the machine is in safe
condition to use, both mechanically and electrically. If the authorised operator
cannot make good any malfunction of the machine then this must be reported to
his immediate supervisor who will take appropriate action to repair the machine.
If this cannot be achieved then the machine will be electrically isolated and locked
off until an appropriate repair can be carried out. It is the responsibility of each
authorised operator to check that the machine is safe to use prior to its operation
however it is equally the responsibility for each person to leave the machine in a
mechanically and electrically ‘neutral’ state such that inadvertent energizing
cannot cause harm to anyone moving on to it. The elements of the machine,
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stationary and moving, (e.g. chucks, cutting tools, vices, drills etc.) must be
properly secure.
Guards required for safe operation of machines, must be fitted, as far as is
reasonable and practicable.
The machine beds, tables and slide ways should be free of tools, (spanners, drills,
etc.) and materials (off-cuts, job items, etc.)
Chuck keys must me removed when not actually tightening or loosening the
chuck. This is particularly important when using a lathe or drill.
The machine must be clear of excessive swarf and be sufficiently illuminated.
Safety stops on a machine must be clearly indicated and their location know to the
operative.
Before
1.1.4 The CNC Milling Machine
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Only authorized and trained personnel should operate this machine.
Before operating the machine check for damaged parts and have them repaired or
replaced.
The machine is automatically controlled and may start at any time.
Do not operate with the doors open.
Do not enter the machine area anytime that the machine is in motion.
Always wear safety goggles.
Never place your hand on the tool in the spindle and press ATC FWD, ATC REV,
NEXT TOOL, or cause a tool to change cycle. The tool changer will move in and
crush your hand.
The spindle head can drop without notice. Avoid the area directly under the
spindle head.
Improperly clamped parts machined at high speeds/feeds may be ejected and
puncture the safety door. Do not machine oversize or partially clamed pieces.
Windows must be replaced if damaged or severely scratched.
Do not process toxic or flammable material. Deadly fumes can be present.
Consult material manufacturer for safe handling before processing.
Always remove the power before servicing the machine.
Do not reset a circuit breaker until the reason for the fault is investigated. Only
Haas trained personnel should troubleshoot and repair the machine.
Follow these guidelines while performing jobs on the machine:
Normal operation - Keep doors and guards in place while machine is operating.
Part loading and unloading – An operator opens the door or guard, completes
task, closes door or guard before pressing cycle start (starting automatic motion).
Tool loading or unloading – A machinist enters the machining area to load or
unload tools. Exit the area completely before automatic movement is commanded
(feg. Next Tool, ATC/Turret, FWD/REV).
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Machining job setup – Press emergency stop before adding or removing
machine fixtures.
Maintenance/Machine cleaning – Press emergency stop or power off the
machine before entering the enclosure.
Unattended operation: The fully enclosed machine is designed to operate unattended;
however the machine process may not be safe to operate unmonitored.
The machining process must be monitored to prevent damage if a hazardous condition
occurs. For example, if there is a risk of fire due to material being machined then an
appropriate fire suppression system must be installed to reduce the risk of harm to
personnel, machine and building. It is especially important to select monitoring
equipment that can immediately perform an appropriate action without human
intervention.
It is the technicians responsibility to set up the machine safely and to use best practice
machining techniques. If there are any doubts at any stage then the Senior Mechanical
Technician should be consulted.
1.1.5 The CNC Lathe
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Only authorized and trained personnel should operate this machine.
Before operating the machine check for damaged parts and have them repaired or
replaced.
The machine is automatically controlled and may start at any time.
In normal operation the machine should be used with the doors closed. For certain
tasks the machine can be operated with the doors open but the chuck guard must
be in place.
Do not enter the machine area anytime that the machine is in motion.
Always wear safety goggles.
Improperly clamped parts machined at high speeds may be ejected and puncture
the safety door.
Do not exceed the rated chuck rpm.
Higher rpm reduces chuck clamping force.
Unsupported bar stock must not extend past the draw tube end.
Chucks must be greased weekly and regularly serviced.
Do not machine parts larger than the chuck.
Follow all of the chuck manufacturers warnings regarding the chuck and work
holding procedures.
Hydraulic pressure must be set correctly to securely hold the work piece without
distortion.
Windows must be replaced if damaged or severely scratched.
Do not process toxic or flammable material. Deadly fumes can be present.
Consult material manufacturer for safe handling before processing.
Always remove the power before servicing the machine.
Do not reset a circuit breaker until the reason for the fault is investigated. Only
Haas trained personnel should troubleshoot and repair the machine.
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Follow these guidelines while performing jobs on the machine:
Normal operation - Keep doors and guards in place while machine is operating.
Part loading and unloading – An operator opens the door or guard, completes
task, closes door or guard before pressing cycle start (starting automatic motion).
Tool loading or unloading – A machinist enters the machining area to load or
unload tools. Exit the area completely before automatic movement is commanded
(feg. Next Tool, ATC/Turret, FWD/REV).
Machining job setup – Press emergency stop before adding or removing
machine fixtures.
Maintenance/Machine cleaning – Press emergency stop or power off the
machine before entering the enclosure.
Unattended operation: The fully enclosed machine is designed to operate unattended;
however the machine process may not be safe to operate unmonitored.
The machining process must be monitored to prevent damage if a hazardous condition
occurs. For example, if there is a risk of fire due to material being machined then an
appropriate fire suppression system must be installed to reduce the risk of harm to
personnel, machine and building. It is especially important to select monitoring
equipment that can immediately perform an appropriate action without human
intervention.
It is the technicians responsibility to set up the machine safely and to use best practice
machining techniques. If there are any doubts at any stage then the Senior Mechanical
Technician should be consulted.
1.1.6 The Work Piece
 The work to be machined must be securely held mechanically or/and clamped
without excessive unsupported overhang.
 On the drilling machine hand-holding the work piece should be avoided, especially
thin sheet metal work pieces.
 Ensure that any long bar that may protrude from the rear of the lathe is properly
guarded and supported. This is especially true when small diameter bar is being
machined as it could easily bend when rotated at high speed.
 Slender work pieces must be supported in a safe approved manner (i.e. with
steadies, back centres, jacks etc.)
 Lathe speeds and cutter speeds must be appropriate to the work and material in
hand.
 Light tubular work pieces should be suitably plugged before gripping to prevent
“spring-out” when tool pressure is applied.
1.1.6 The Work Area
 The work area must be of sufficient size for the safe movement of the operator and
for the movement of staff passing the operator, and all machines should be laid out
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in such a manner as to allow free passage and a lack of interference with other
operatives.
 The work area must be clear of obstructions such as materials, finished work
items, machine accessories, etc.
 Skid mats, if necessary, should be installed at each machine.
 The work area must be clear of lubricants or coolant spillage’s and free of swarf.
1.1.7 Procedures
 Overalls must be kept buttoned and be in good condition with no loose or torn
areas which could easily get entangled in moving parts of machinery.
 Hair must be kept short or wear a hat. This is especially important whilst
operating vertical drilling machines.
 Only one person must operate a machine at any one time.
 Always use a brush or rake to remove swarf.
 Make sure that files and scrapers are fitted with handles when de-burring
removing sharp edges.
 Compressed air must only be used for cleaning parts or inaccessible areas only.
Never direct compressed air at anyone. It has been known for people to be killed
by fooling around with compressed air. Never under any circumstances blow
compressed air into someone’s back passage. This foolish act can literally blow
your insides out !
 When the coolant supply directed at the work piece has to be adjusted, this must be
done, as far as reasonable and practicable, when the machine is stopped.
 Eye protection must be worn by the operative.
 Machines must be stopped when taking measurements, adjusting tools or the work
piece, and cleaning swarf.
 Proper bar rests must be used when using internal and external hand chasers, and
properly positioned to prevent “bite”. Freehand chasing must not be permitted.
 Hand sawing-off the lathe must only be carried out with the machine stopped/
 When using emery paper on rotating work piece, always keep fingers well clear. It
is very easy to get a thumb trapped between the revolving work piece and the
emery paper. Use emery sticks whenever possible.
 Rags and dusters etc., must be kept well away from rotating work and tools.
 When finishing work on a machine the machine must be left in an electrically and
mechanically neutral condition. This means switching off electrical power and
disengaging any drive gears such as the lead screw. The machine should also be
cleaned down removing any swarf etc to appropriate bins.
1.2 Cylindrical And Surface Grinders
These are machines which are situated in the machine shop area but because of their
specialised nature require to be treated with care. The following notes also apply to floor
standing or pedestal grinders which are used for tool sharpening.
Abrasive wheels must be mounted and dressed only by competent and trained personnel
who have a certificate defined under the Abrasive Wheel Regulations.
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Before being used, a grinding wheel should always be examined thoroughly and tested by
tapping with a light non-metallic implement before fitting to the machine. Once fitted,
guards should then be placed in position and the wheel dressed. Suitable racks should be
used for storing grinding wheels.
On no account should abrasive wheels be mounted on makeshift apparatus. Floor
standing grinders should be fixed to a good foundation. Bench grinders should be
securely anchored to a stout bench. Work rests should be kept adjusted as close as
possible to the wheel to prevent the work piece getting between the wheel and the rest.
The maximum distance should be not greater than 2mm. The necessary adjustments must
not be made with the wheel in motion. Rests should be examined periodically and
maintained in good condition.
Means of starting and stopping grinding machines should be placed in a safe position
within easy reach of the operator.
When mounting abrasive wheels the paper washers supplied by the wheel manufacturers
should always be used so as to distribute the clamping pressure of the flange evenly on
the wheel. Before a wheel is mounted a check should be made to ensure that the
operating speed of the spindle is not greater that the maximum operating speed marked
on the wheel.
It must be remembered that the centrifugal force on a grinding wheel increases not
directly with the speed but as the square of the speed.
1.2.1 Wheel RPM
The RPM of the grinding wheel spindle must be clearly marked in a prominent area.
1.2.2 Magnetic Chuck
Operators of surface grinders must ensure that the magnetic chuck is on before starting
grinding or wheel dressing operations. This is particularly important when working with
components that take on some residual magnetism which can give the impression that the
chuck is on when in fact it is off ! ALWAYS CHECK THE POSITION OF THE
ON/OFF LEVER BEFORE COMMENCING WORK
1.3 Machine Maintenance – Disconnection From Power Source
Before undertaking maintenance on a machine the source of power must be removed or
otherwise disabled. Lockout devices for different type of connections are available from
the Senior Technicians.
Where the machine is connected to the power source by a removable plug, the plug must
be removed from the socket and a lockable cover fitted over the plug. Alternatively the
plug can be taken back to the work area so that it is within site of the maintenance
personnel.
Where the equipment is connected by a permanent wired outlet, the outlet must be
isolated and locked off. Where two or more people are working together each person
must use a separate padlock and key.
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When leaving the area, even for a short while, you must check that the isolation is still in
place before recommencing work.
1.4 The Welding Fabrication and Fitting Shop
Within this area there are six areas that need to be examined with regard to health and
safety issues and these are:
 General Safety
 Welding and brazing
 Fitting and Fabrication
 Lifting and lifting equipment
 Storage and handling of materials
 Painting and paint spraying
1.4.1 General Safety
a) Ventilation: Ventilation becomes a critical factor in preventing oxygen
deficiency during heavy or long periods of welding, all types of welding produces
some degree of toxic fumes and it is therefore necessary to have sufficient
ventilation of the work area to protect the operator. A system of LEV as installed
in the fabrication shop must be used to prevent a build up of welding fumes when
welding in this area. The LEV will be examined and tested every 14 months by a
qualified third party and certification pertaining to this will be maintained by the
TRO or his nominee.
b) Protective Clothing: The wearing of heat-resisting gloves is common-sense and
essential to prevent burns from the work piece, sparks and spluttering metal,
except when very light welding is taking place and where the work piece can be
handled safely with tongs, pliers etc.
Do not keep a box of matches or butane lighter in the pockets of overalls. It has
been known for a butane lighter to explode from the heat of a stray spark or flame
with consequent disastrous consequences.
Again, for heavy welding and cutting, fire resistant overalls or aprons of approved
design must be worn. These should not have pockets so that molten metal and
sparks cannot be trapped. Any clothing worn underneath the overalls or aprons
should not have rolled-up sleeves, cuffs or trouser turn-ups for the same reason.
For heavier types of welding, and cutting, long boots or welder’s spats must be
worn. Ordinary shoes tend to trap molten metal, splutter and sparks, causing
burns of the feet and ankles.
THE WEARING OF NYLON OVERALLS AND JACKETS IS
PROHIBITED WHEN WELDING OR CUTTING.
UNLIT TORCHES MUST NOT BE DIRECTED TOWARDS CLOTHING,
ESPECIALLY IF DAMP. GAS ENTRAPMENT CAN CAUSE CLOTHING
TO IGNITE READILY.
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c) Eye Protection: The wearing and use of eye protection goggles or face shields
are absolutely essential for welding and cutting operations. Goggles suitable for
gas welding should only be used for gas welding. Arc welding requires the use of
a shield to protect the face, and which is fitted with a window of special dark
glass through which the arc can be safely viewed. The arc must never be “struck”
without the face shield in the protective position. The electric arc produces
intense ultra-violet and infra-red rays of such intensity that the recommended
distance to view with the naked eye is 15 metres, and only then if accidental or if
necessary.
Goggles and face shields must be in good condition i.e. there must be no cracks or
chips in the protective glass, and no burn holes or parts broken off the face shield,
and the head harness complete and fitting correctly.
FAILURE TO TAKE THESE PRECAUTIONS MAY RESULT IN PART
OR TOTAL BLINDNESS, OR IN EXTREMELY PAINFUL CONDITIONS
OF THE EYES.
It is essential to consider the safety of others in the vicinity of welding
operations, as well as the welding operator, and, where required, fire resistant
screens should be placed around the immediate welding area in such a manner
that the welding operation cannot be viewed by others. It should be remembered
that reflections from walls, ceilings and other objects can be of such intensity as
to cause eye problems to others. Persons assisting with a welding operation must
also wear the appropriate eye protection.
Eye protection in the form of clear-glass goggles must be worn for weld chipping
or grinding.
d) Ear Protection: Where heavy or prolonged gas welding or cutting operations are
carried out for long periods, ear protection of recommended design must be work
to prevent ear damage from noise. This also prevents fumes, dust, sparks or chips
of metal or flux from entering the ears and can prevent the possibility of damage
or infection.
e) 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 work
piece has cooled off.
1.4.2 Welding Brazing and Fitting
a) Oxy-Acetylene Welding: Oxygen and acetylene cylinders, because of the high
pressures of the gases they contain, necessitate special care in storage, handling
and installation.
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The oxygen cylinder usually contains a higher pressure than the acetylene
cylinder, and the acetylene cylinder fittings are left-handed.
Oxygen and acetylene cylinders must be stored vertically in a designated area
away from the risk of fire, heat and sources of ignition. In compliance with this
requirement a cage for cylinder storage is provided outside of the workshop
adjacent to the Fraser Noble Building rear exit. As 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 to return “empties” immediately to the
storage area and to 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. Line
snubbers and flash-back arrestors to the most recent British Standard
Specification must be in position for both oxygen and acetylene 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 “blowing-off” or “snifting” the cylinders prior to installing the regulators
(as is standard practice to clear the gas cylinder outlets of dust and dirt) , the
following procedures must be followed :
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Ensure there is nothing in the way of the gas jet.
There are no naked flames are in the vicinity.
Eye protection and gloves must be worn.
Do not look into the cylinder valve.
All cylinders must carry a label. The label is the only sure means of identifying
the gas inside the cylinder. It may also give the pressure the gas is stored at and
outline basic safety requirements in accordance with Chemical (Hazards
Information and Packaging for Supply) legislation. The label should be complete
and be attached to the cylinder.
DO NOT USE A CYLINDER IF THE LABEL IS MISSING OR BADLY
DAMAGED.
NEVER RELY SOLELY ON THE COLOUR OF THE CYLINDER TO
IDENTIFY ITS CONTENTS. READ THE LABEL!
The hoses and regulators must be in first-class condition. If not, replace
immediately. Welding nozzles (if threaded types are used) must be undamaged
and screw freely into the gun to produce a tight seal. The welding gun should be
also in first-class condition and checked periodically for leakage 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 the cylinders can be quickly shut off.
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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.
High pressure oxygen reacts violently with oils, greases, tarry substances and
some solvents. This includes things like soap, butter and some hand creams.
When testing for suspected leaks use a solution of 1% TEEPOL H87 (Teepol is a
registered trade mark of Shell) in water applied with a brush, or leak detecting
fluid available from BOC.
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 a pressures above 15psi Above this
pressure it is extremely unstable and may explode.
Acetylene gas must never be allowed to come in contact with unalloyed copper
(e.g. copper tubing) with the exception of the welding torch nozzle. Copper
acetylide will form which is an extremely reactive chemical which can explode
violently.
REMEMBER: ACETYLENE IS A HIGHLY FLAMMABLE AND
EXPLOSIVE GAS.
There are other very valuable sources of literature on safety with gases published
by the HSE and BOC. These are “Take Care with Acetylene”, “Safe Use of
Compressed Gasses in Welding”, “Flame Cutting and Allied Processes” and
“Safe Under Pressure”. These are available from the TRO.
b) Arc Welding: Electric arc welding need not be a hazardous process if prescribed
precautions are followed, such as have been detailed in previous chapters.
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 periodically. 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 un-insulated part of the electrode
holding coming in contact with the “earthed” job or the earthing clamp while the
current is switched. 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.
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c) Spot, T.I.G., M.I.G. Welding: The Safety rules and precautions for gas and arc
welding, as previously enumerated, apply in general to all other types of welding.
d) 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 and must be in good condition.
LEV style fume extraction must be used as most brazing rods contain percentages
of zinc, phosphorus, copper etc., all of which when heated produce highly
poisonous fumes. In addition, many brazing fluxes are corrosive and toxic fumeproducing. The corrosive fluxes are usually removed when brazing is completed
and suitable gloves must be worn for the washing operation to avoid skin
complaints and the eyes are 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 and the
operator should keep as far back from the work piece being silver-soldered as is
practical to avoid the fumes.
After prolonged welding, any operative suffering form chest complaints should
report immediately this fact to his supervisor.
1.4.3 Fabrication and Fitting
a) Guillotine: The authorised operator must ensure that all moving parts of the
guillotine are guarded and that interlocking guards are correctly fitted and
working correctly prior to using the guillotine. Any malfunction must be reported
to the Supervisor immediately. Care should be taken when handling large sheets
of steel material and the use of protective gloves should be used provided there is
no danger of getting trapped in moving machinery.
b) Horizontal Bandsaw: Ensure that long bars which are being cut are properly
supported using trestles. Any short pieces of material that are gripped in the vice
should be supported at other end of vice with similar sized material. Fragile
plastic tubes should be supported by inserting a suitable sized piece of material
onto the base thus preventing the tube from spinning round whilst being cut. Care
should be taken when changing blades especially when uncoiling a new blade.
The use of gloves is imperative and the machine must be electrically isolated.
c) Linisher: Before using the linisher always check there are no cuts or holes in the
abrasive belt by hand rotating the belt one complete turn. Do not use if it is
damaged as the torn edges could easily catch on the work piece and throw it
violently. Always ensure that the work piece is resting against the fence during
11
the linishing process and that the fence is properly maintained with only the
minimum of clearance between the fence and the moving belt.
Take great care to ensure that the work piece does not have any small protrusions
which could get jammed between the fence and the rotating belt.
The temptation to use gloves whilst linishing is very great as the work piece can
get hot quite quickly. This is something that must be avoided as any loose fitting
gloves could very easily be pulled into the gap between the fence and the rotating
belt. Have a container of cold clean water handy to keep the work piece cool
d) Hand Tools: All files and scrapers etc. must be fitted with the correct size of
handle. Hammer heads must no be allowed to become loose. Chisel heads should
not be allowed to become “mushroomed”.
Hardened steel components must not be struck or hammered with another
hardened component (e.g. H.S.S. tool bits struck with a steel hammer). They can
very easily splinter and cause serious eye injury.
e) Portable Tools: All portable electrical equipment must be regularly inspected
both electrically (PAT) and mechanically every 12 months. This will be carried
out in house by suitably qualified personnel.
An RCD (Residual Current Device formerly known as an Earth Leakage Circuit
Breaker or ELCB) must be used when working in environments outside the main
workshop area.
Wheels for portable grinders may be obtained in types suitable for either low or high
speeds and care is necessary to ensure that a low speed wheel is not fitted to a high speed
machine.
Before changing a wheel, portable grinders must always be disconnected from either the
electricity supply or the air line.
Machines should be regularly checked and tested, particular attention being paid to
the flexible cable.
Only persons possessing a Certificate defined under the Abrasive Wheels Regulations
may change or dress abrasive wheels.
More information can be had in the Health and Safety at Work Book “Safety on the use
of Abrasive Wheels”. HS(G)17 and also “Maintaining Portable and Transportable
Electrical Equipment” HS(G)107
The maximum operating speed marked on an abrasive wheel should not be exceeded
under any circumstances.
The grinding wheel guard must always be in position and properly adjusted before a
wheel is run.
Truing and Dressing: Wheels used for off-hand grinding should be frequently trued to
eliminate out-of-balance conditions and to enable the work rest to be adjusted close to the
wheel surface.
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Cutting-Off Wheels: The correct wheel for the job, as recommended by the wheel
maker, should be used. Cutting-off wheels should be inspected before mounting for
possible warping or other defects. A warped wheel may cause excessive vibration at high
speeds, side pressure, or heating and possible wheel breakage. Cutting-off wheels should
be mounted only on machines designed for their use. Power should be adequate,
otherwise stresses may build up and the wheel may stall and break. Pressure should be
applied evenly. Care should be taken to avoid twisting or exerting pressure on the side of
the wheel. The work piece should be rigidly supported and firmly clamped. Lack of
rigidity either in the wheel or the work piece can lead to wheel breakage.
1.4.4 Lifting and Lifting Equipment
Maintain all lift trucks regularly in accordance with the manufacturers instructions. All
lifting equipment will be load tested every 12 months by a qualified third party and
records will be maintained by the TRO or his nominee.
 Ensure operating surfaces are strong enough, well maintained and not too steep.
 Do not use forks, pallets or bins to lift persons to work at heights unless these are
suitably modified; use properly designed work platforms.
 All chains, ropes, lifting tackle, hoists and lifts must be thoroughly examined
every six months by a competent person (often employed by an insurance
company); obtain and keep the report. In addition a load test will be carried out
every 12 months by a qualified third party and records will be maintained by the
TRO or his nominee.
 Lifting appliances shall be used only by or under the direct supervision of,
persons who are qualified by training, or experience, to use the appliances in a
proper and safe manner.
 All lifting appliances and equipment must have test certificates and clearly
marked with S.W.L. (Safe Working Load).
 Every part of a load shall be securely suspended or supported and secured to
prevent danger from slipping or displacement.
 The lifting of a load should be halted after the load has been raised a few inches
and the security of the slinging attachments should then be checked before
proceeding with the operation.
 Take adequate steps by the use of suitable packing or otherwise to prevent the
edges of a load from coming into contact with any sling, rope or chain.
 Make sure slings or straps have no frayed parts or cuts.
 When using shackles ensure that the pin is screwed properly into place.
 If a lifting hoist has to have chains lowered, make sure no-one is under them and
lower the chains, don’t drop them.
 If lifting with a fork lift (of pallet truck), make sure the load is secure.
 Never stand under a hoist, a fork lift or any lifting appliance. Keep your feet
clear.
1.4.5 Storage and Handling of Materials
When moving and storing materials all personnel will:
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 chock objects which may roll, such as drums, and keep heavy articles near floor
level
 inspect pallets, containers and racks regularly for damage. Prevent damage from
fork-lift trucks and other vehicles
 stack palletised goods vertically on a level floor so they won’t overbalance.
 ‘key’ stacked packages of uniform size like a brick wall so no tier is independent
of another.
 use a properly constructed rack where possible - and secure it to a wall or floor.
And will not:
 allow items to protrude from stacks or bins into gangways
 climb racks to reach upper shelves - use a ladder or steps
 lean heavy stacks against structural walls
 de-stack by throwing down from the top or pulling out from the bottom
 exceed the safe loading of racks, shelves or floors.
Sharp edges: These cause as many as a third of all accidents in some engineering
workshops, resulting in cuts, abrasions, infected wounds, dermatitis, amputations and
occasionally fractures. Those working with sheet metal, either flat or coiled, heavy sharp
items, such as tools and cutters, and scrap metal and swarf are most at risk. Consider how
to avoid handling sharp edges, and if this is not reasonably practicable, reduce exposure
to them. Reducing the risks:
 Remove sharp edges or protect them before handling.
 Avoid handling by using, for example, trays, jigs, holders or baskets.
 Store articles correctly so that they are retrieved easily.
 Use personal protective equipment such as gloves, gauntlets and aprons, but only
where these do not add to other risks from machinery, such as entanglement.
1.4.6 Painting and Spray Painting
Access to a fully ventilated paint spray booth is via the Geotechnics lab.
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1.5 The Woodworking Shop
It cannot be overstated that Supervisors of Workshops must diligently enforce the legal
and statutory regulations regarding the safety requirements for the preparation and
operation of all wood working machines in their charge.
Wood working machines (e.g. circular saws, planers, routers, spindle moulders, bandsaws
etc.,) are inherently hazardous in operation due to a number of factors, including:
 the cutters are necessarily sharp, run at very high speeds and are always partly
exposed.
 unlike most other mechanical workshop machines, the work piece is not normally
clamped and the operator must manually present the work piece to the cutter.
 wood is a natural material and has may imperfections which tend to alter the
normal progress of the cut and/or feed and sudden changes in texture may
introduce additional safety hazards (e.g. snatching, throw-back etc.,)
IMPORTANT
 It is unlawful for untrained personnel to operate woodworking machines
and/or be permitted to ‘take off’ or assist at the machines.
 Only personnel who have been qualified and certificated by Aberdeen
College as authorised operators will be permitted to use woodworking
machines. A list of qualified personnel will be displayed in the workshop.
 Due to the restricted workspace only two persons may work in the
woodworking shop when fixed machinery is in operation.
1.5.1 Training
It is normal practice in University engineering workshops to employ personnel already
trained in metalworking and with the view to subsequently training them in woodworking
techniques.
Since these machines are used intermittently and often with long periods between usage
and extended period of comprehensive training may be necessary for the ‘trainee’ to
reach an acceptable standard of competence and reliability.
The workshop supervisor must ensure that all ‘trainees’ are not subjected to risk and that
they receive clear and positive instruction on all the operations of the machines including
their safety regulations which must be enforced by careful and diligent supervision.
There is an extensive range of woodworking machines which each having its relevant
safety requirements. Some examples of the requirements would include:


All woodworking machines and their cutters and attachments must be properly
used and maintained.
All machines must be fitted with the necessary approved safety guards and
attachments and it must be insisted that they are used and properly adjusted by the
operators.
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Adjustable guards/covers must be fitted where there are unused and exposed
sections of cutters (e.g. cutter blocks behind the guide fence on planers, saw
blades projecting under saw benches etc.).
An emergency (mushroom type) stop button, additional to that fitted on the
started, must be suitably sited adjacent to circular saw benches.
A “push-stick” of the recommended dimensions must always be sited at circular
saws and they must be used by the operator (when applicable).
Operators must wear suitable eye protection during all cutting operations
(additional protective equipment may also be necessary - e.g. ear defenders/plugs,
respiratory masks etc.).
For the operators safety there must be adequate space around the machine for the
throughput of the work piece and floors must be kept clear of off-cuts and other
hazards.
As indicated in (6) respiratory masks are also provided as an extra precaution and
should be used in conjunction with the local exhaust ventilation (LEV) system
where heavy wood dust contamination is likely.
The LEV system must be used at all times when using all the permanently fixed
woodworking machines.
The LEV system must be thoroughly examined and tested every 14 months by a
suitably qualified and competent third party. Records of these inspections will be
maintained by the TRO or his nominee.
When a woodworking machine has been switched off ,the machine should not be
left unattended until the cutter has stopped turning.
There are three machines which are in regular use in the woodworking shop and these
are:
 The circular saw
 The planer and thicknesser
 The cross cut saw
There are many safety procedures that must be adhered to before attempting to operate
these machines. These specific procedures should be well known to the trained operator,
but as these machines are used on an irregular basis, there is available, as an “aide
memoir ”, three separate safety notes on each machine.
These notes will be displayed prominently in the woodworking shop for easy and quick
reference.
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2. CODES OF PRACTICE FOR ELECTRICAL/ELECTRONIC WORKSHOP
2.1 Electricity
The dangers from electrical installations or equipment are broadly of two kinds:


Injury to persons
Damage to buildings and equipment
2.1.1 Electric Shock
Electric shocks occur when contact with a live conductor causes sufficient current to pass
through the body to cause an injury. As a rough guide, voltages exceeding 50V ac or
120V ripple free dc should be considered hazardous in a dry, unconfined, non-conductive
location. These voltages must be reduced if the location is wet, confined or conductive. A
simple rule is to consider all voltages above 35V either dc or ac as potentially hazardous.
The effect of electricity on the body depends on the strength of the current and the path
the current takes. The heart is the most critical organ and current flowing from hand-tohand or hands-to-feet can be considered as passing through the heart. The size of the
current depends on both the voltage of the supply and the resistance of the skin. Skin
resistance is very much reduced when the skin is wet.
The table gives typical effects for various currents:
1mA
5mA
10-20mA
50mA
100-300mA
3-8 Amps
8 Amps
Threshold of feeling.
Maximum ‘safe’ current.
‘Let-go’ current limit.
Severe pain. Inability to let go; possible paralysis.
Ventricular fibrillation leading to death.
Sustained cardiac contraction. Burns. Possible respiratory arrest.
Severe burns, probably fatal.
The most common cause of death from electric shock is ventricular fibrillation (failure of
the heart to pump blood) and not respiratory failure, unless the shock is via the head.
The electrical resistance of the body can vary enormously from person to person and in
the same person at different times and under different conditions (stress, environmental
etc.). This resistance can be as high as 10k or as low as a few hundred ohms, depending
on whether the skin is dry or moist.
Even with a resistance of 10k the 230Vac mains supply will result in a current of more
than 20mA, which could be lethal. In fact, much lower voltages can be dangerous and
death has been recorded from only 60V.
It will be appreciated that the above remarks apply essentially to current passing through
the body, e.g. from hand-to-foot or hand-to-hand. It is possible for part of the body, e.g.
finger to short two conductors of differing potential or a charged capacitor or a battery.
This will not necessarily result in electric shock as described above, but can inflict severe
burns.
2.1.2 Treatment for electric shock
17
Immediate action is required. Check whether the subject is in contact with the supply. If
so, then switch off the appliance or disconnect the supply at the mains outlet or withdraw
the plug. Only if this is not possible, then arrange to pull the subject away using suitably
insulating material (piece wood, wooden broom, scarf, etc.).
Even if the subject is still conscious, check for pulse in the wrist and neck. If no pulse can
be felt, then further immediate action is necessary.
Immediately call for medical assistance by dialling 9-999 and asking for an ambulance,
emphasizing that it is a ‘cardiac arrest’. Do not waste time on this - send someone else if
possible.
Send for a qualified First-Aider and for someone qualified in the use of a defibrillator.
2.1.3 Burns
Burns can be caused by the passage through the body of a heavy current. Burns can also
be caused by the intense heat generated by the arcing from a short circuit (a high capacity
1.5v battery is sufficient to cause burns when short-circuited). The actual depth of the
burn is likely to be greater than it appears, with damage to underlying tissue, although its
area may be small.
All cases of burns require immediate medical attention either from a qualified FirstAider, the Hospital’s Accident and Emergency Department or the persons own doctor
depending on severity.
2.1.4 Radiation induced injuries
Electrical apparatus frequently emits electromagnetic radiation which can be dangerous.
The majority of equipment that workshop personnel will be working on will be of an
insignificant level however the dangers must be considered.
Ultra-Violet radiation: UV radiation from lamps (as used in PCB manufacture or as a
biological sterilizer) or electric welding is absorbed by the outer layers of the eye and
conjunctivitis can result. When working with UV sources suitable eye protection must be
worn. In the case of the PCB exposure unit which is shielded around the source it is
sufficient to avoid looking directly into the source (the bulb). Exposed skin must be
covered with gloves or kept out of the direct light.
Micro-wave, radio-wave radiation: Microwave and radio-frequency radiation can be
absorbed by the body, particularly the nerves and the eyes. Serious internal damage can
occur if any part of the body is exposed to microwave energy. The skin and internal
organs can literally ‘cook’ and prove fatal.
The highest microwave energy level to which operators should be subject is 1 mW/cm2
and intensities exceeding 10 mW/cm2 must always be avoided. If technicians have had
bones pinned with metal at any time, or have cardiac pacemakers, they must not to
expose themselves to microwaves as they may cause substantial internal damage before
being aware that she/he is in danger.
Sources of microwave radiation can of course be from ovens, and transmitters. Many
telephone and satellite transmitters are sited on University roofs and it is important not to
18
walk past, stand or work anywhere near the front of these. If work is necessary near a
transmitter then the supervisor must be contacted in order to assess the danger and if
necessary to arrange for the transmitter to be closed down. No sources of microwave will
be worked on without first contacting the supervisor.
Induction Heaters: Any metal object in or near an induction heater will receive energy
and heat up extremely rapidly. No ring or other metal trinket should be worn when in the
vicinity of an induction heater nor should any metal be held in the hands as burns may
occur in fractions of a second. In general no part of the body should come within 2 feet
(60cm) of an induction heater coil. There is an additional danger to those with metal bone
pins, pacemakers and these individuals should avoid such heaters.
X-Rays: Electronic equipment containing Cathode Ray Tubes (CRT’s) can emit X-Rays.
These can be harmful although shielding is usually provided in modern equipment, and
the dangers are low especially due to the infrequency of the work on this type of
equipment.
More dangerous are the ‘true’ X-Ray sources such as found in departments such as
Chemistry. Adequate safeguards must be in place to prevent the danger of exposure to XRays. The supervisor must be contacted to assess the danger before commencing work on
X-Ray equipment. No work involving X-Ray equipment will be worked on without first
contacting the supervisor.
2.2 Buildings and Supplies
All electrical installations normally fixed as part of a building (e.g. sub-stations, mains
outlets, switchgear, power circuits, permanent lighting, emergency lighting, fire alarms,
fuse boards etc.) are the responsibility of the Estates Section. In order to maintain, alter
and upgrade these installations the Estates Section employs qualified electricians or, if
necessary, outside approved electrical contractors. All work is executed in accordance
with the latest edition of the IEE regulations and British Standard Code of Practice.
Persons other than the above operatives must on no account alter or interfere with any of
the installations. No attempt to repair fuses or circuit breakers should be made. Any fault,
blown fuse or tripped circuit breaker must be reported immediately to the Estates Section
and the matter will receive the attention of the Estates Electricians.
Only Estates personnel are permitted to connect/disconnect equipment to permanently
wired outlets.
2.3 Hazardous Areas
Certain areas where personnel are required to work on electrical equipment are hazardous
and can be broadly split into two types:


those where water or aqueous chemicals can enter electrical equipment
those where there is a risk that flammable vapours or dust can be ignited by
electrical equipment.
In both cases work should be carried out in the workshop if at all possible.
2.3.1 Wet area - Field work, greenhouses, aquariums and animal houses
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The electrical dangers associated with these areas are those of damp, wet or corrosive
conditions with non-insulated structures and flooring. The dangers are one of shock and
short circuit. All equipment must therefore be designed for the purpose and suit the
environmental conditions.
Connections must be waterproof and secure with earth connections being particularly
important.
RCD’s must be used when working on equipment in these areas.
2.3.2 Cold Rooms
Cold rooms provide a particular problem. While the atmosphere is frequently very dry,
condensation can occur, particularly when equipment is removed from the room. Ensure
that equipment removed from a cold room has ‘warmed up’ before attempting to use it.
2.3.3 Areas with flammable or explosive atmospheres
These areas require equipment to be spark-proofed and which does not get hot. Adequate
earth connection is vital. Normal electrical equipment must not be used in these areas.
Equipment requiring maintenance must be removed from these areas before commencing
work.
2.4 Isolation From Mains And Protective Devices
2.4.1 Isolation
Except in circumstances where live working (section 2.7) is absolutely necessary,
equipment being worked on must always be isolated from the supply.
Where the equipment is connected to the power source by a plug, the plug must be
removed and a lockable cover fitted over the plug. The key to the padlock will be
retained by the person carrying out the work. Alternatively the plug can be taken back to
the working area so that it is permanently visible to the maintenance personnel.
Where the equipment is connected by a permanent outlet, the outlet must be isolated and
locked off with a suitable padlock and the person carrying out the work must retain the
key. Where two or more people are working together each person must use a separate
padlock and key. In all cases lockout devices must be returned at the end of the job.
After leaving the work area, even for a short while, you must check that the equipment is
still isolated before recommencing work.
Notices such as ‘Danger - Men working on conductors’ must be posted on all isolated
equipment.
2.4.2 Transformers and low voltage supplies
Transformers provide a means of isolating equipment from the mains supply. Portable
tools used in hazardous areas such as building sites should normally be powered from a
110Vac transformer centre tapped to earth (limiting a shock to earth at 55Vac). However
as most tools used by workshop personnel are rated at 230Vac, a 230Vac double wound
isolating transformers is an alternative; although in view of the weight and bulk of the
20
transformers, it may be more convenient to use an RCD adapter. The 230Vac isolating
transformers are a valuable aid in test benches when danger exists from the live chassis of
equipment under repair.
It should be noted that isolation transformers do not protect against electric shock
altogether. The output terminals of the isolation transformer could have the same lethal
potential if touched.
Auto transformers and Variacs do not provide isolation from the mains and must never be
used for the purposes of providing isolation.
Low voltage (< 50V) dc supplies are generally safe but can be a danger when several are
wired in series to give a higher voltage.
2.4.3 Batteries
Either single or banks of batteries can be used to provide power supplies isolated from
the mains. Such supplies are as dangerous as a mains supply of equivalent voltage and
must be treated with appropriate precautions.
Since high currents can flow if batteries are short circuited, care must be taken to ensure
that short circuits cannot occur. Short circuiting batteries pose an explosion risk as well
as a risk of burns. If a lead-acid batteries explode then persons in the vicinity will be
showered with acid.
Lead-acid batteries can release hydrogen and other noxious gasses during charging and so
must be charged in a well ventilated area. The charging should not be higher than the
specified rate to prevent overheating.
2.4.4 RCD Protected Outlets, Adapters and Other Protective Devices
RCD adapters are available for use out-with the workshop which itself is protected by
built in RCD’s. These must be carried as part of the standard toolkit and used always
when working on portable mains equipment (IE fitted with 13A plug) with exposed live
terminals.
It must be noted that whilst an RCD protected outlet does give added protection against
electric shock from the mains, it does NOT guard against electric shock altogether. For
example most electronic, and some electrical equipment are isolated from the mains via a
transformer. On occasions the voltage on the output of the transformer or the voltage
generated by the electronic circuitry, such as in a TV, may be high enough to represent a
danger. A person touching a dangerous voltage which is isolated from the mains can
receive a shock which will not trip an RCD. So always keep this in mind when using
RCD’s both here in the workshop and elsewhere. Do not assume it is safe to go straight in
to a piece of equipment just because an RCD is present.
Gloves are available which are tested up to 15000v but are marked for 3000v working.
These should be considered for use in preventing accidental contact and not for actual
live manipulation of wires or terminals. These must be inspected before use for cuts or
abrasions.
2.5 Medical Equipment
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Electronic equipment designed for hospital use or where deliberate electrical connections
are made to the body for the purposes of stimulation or recording of biological potentials
require a specialist service. Whilst minor repairs, for example connectors, can be
undertaken, the workshop cannot undertake any design, manufacture or certification of
such equipment.
The Electronics group within Biomedical Physics carries out care and maintenance of
electro-medical equipment for the Aberdeen Royal Infirmary and peripheral hospitals and
health centres in the region. This includes advice on the purchase of equipment, preclinical acceptance trials to ensure fulfilment of requirements of British and European
safety standards, and planned preventative maintenance and repair. See:
www.biomed.abdn.ac.uk/Services/electronics.shtml
2.6 Workshop Practices
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Electrical/electronic equipment constructed by Central Workshop Services must
be built in a workmanlike manner with care and attention taken to both the
electrical and mechanical construction.
The equipment must be designed, constructed, repaired and maintained to the
highest possible standards and take into account the intended end use, and the
environmental conditions that it will be exposed to. The safety of the end user of
the equipment is paramount
As far as possible the equipment should fail to safety. Access to live parts should
not be possible without removing a screwed down cover. Mains leads should be
of the correct current carrying capacity, be mechanically secured (a knot or a tie
wrap is not sufficient as the cable can twist).
Where the appliance requires an earth to be fitted, the earth lead must be soldered
or crimped to an earth tag firmly screwed down to an earth terminal on the
chassis. The earth terminal must not be used for any other purpose.
All accessible metal part must be constructed so that they are provided with a
permanent and reliable earth continuity path to the main earth terminal. Painted
surfaces must have the paint removed at junctions to provide an adequate path.
Internal wiring and other live conductors must be insulated and secured to prevent
conductors coming in contact with any exposed metal surfaces. Power outlets
from the chassis must be arranged so that the sockets do not expose bare live pins
when disconnected.
Care must be taken to select the correct value of fuse. When connecting mains
plugs to commercial equipment, the manufacturers handbook should be consulted.
Where an instrument has been supplied with a non standard mains lead (i.e.
American colour coding) then the cable should be replaced with a standard UK
cable.
Outside of the Workshop, portable power tools, hand inspection lamps etc.,
should be used with appropriate double wound isolating transformers or RCD’s
(earth leakage circuit breakers).
Charging of lead-acid batteries should be carried out in a well ventilated area to
prevent build up of explosive or irritant gasses.
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
Capacitors may store their charge for some considerable time after the power has
been removed. This can be lethal if high-grade capacitors are charged to
significant voltages. Capacitor must be stored in a discharged state. Discharging
must be done using an appropriate resistance and not by shorting the terminals.
All electrical/electronic equipment produced or repaired by workshop personnel
must be tested and labelled for electrical safety before release. Whenever possible
the tests should be conducted by a person other than the
designer/constructor/repairer. The tests required are earth continuity, and
insulation. More stringent tests including earth leakage may be necessary if the
apparatus is designed for direct patient contact as in, for example, EEG recorders.
2.7 Live Working
The main danger is electric shock causing death or injury to self or others nearby who
may come in contact with live terminals. Other dangers are burns or explosions.
The Electricity at Work Regulations prevents live working unless it is not possible to
repair or test an appliance or installation without the power being applied.
In order to diagnose a fault in electrical/electronic apparatus it is normally necessary to
take test measurements at various places within the circuit with the power applied.
Whenever possible the application of probes to the test points should be done with the
unit switched off and only powering up when everyone is clear of the equipment. This is
not always possible and therefore careful controls are required in order to remove risk of
accidental contact with live terminals (see section 2.7.8). In working with live equipment
it is for test purposes only, no connection or disconnection of live terminals should be
made.
The decision as to whether it is necessary to work with the equipment live is left to the
individual technician with the necessary competency and authorization to perform such
work.
Only fully trained, competent and authorised persons may commence live working on
equipment of any kind. A list of those authorised is displayed in the workshop.
2.7.1 High Current Supplies
Power supplies, including batteries, of a high current rating can be a danger if the
terminals are short circuited. Molten metal can splash into the technicians eyes or severe
burns can occur. It is important when working on this type of equipment that the
terminals cannot short together.
2.7.2 High Voltage (650-3KV) and Extra-High Voltage (>3KV) Supplies
High voltage supplies in excess of 40kV are common place on scientific equipment.
These are particularly dangerous if they have a low source impedance (i.e. if they can
provide a current high enough to be a danger). Where a current is limited by a suitable
series resistor to less than 5mA the supply is often thought of as being inherently safe.
However, there is no clear dividing line of current capacity above which the equipment
can be said to be lethal and below which it is said to be inherently safe. Below 1mA
supplies are not likely to be dangerous. Any capacitors may retaining a lethal charge.
23
All such high voltages must be considered as potentially lethal. No person shall
undertake lone working on high or extra-high voltage equipment with exposed live
terminals.
2.7.3 Medium Voltage Supplies (250-650V)
Much of the equipment used in this category are 415V, 3-phase devices including:
motors, variable frequency drives, furnaces & machine tools. Many are hard wired in to
the building supply or are fitted with sockets to enable disconnection.
All such supplies are potentially lethal. No person shall undertake lone working on
medium voltage apparatus without first discussing the work with a
supervisor/colleague.
2.7.4 Low Voltage Supplies (50-250V)
Voltages exceeding 50Vac or 120V ripple free dc should be considered hazardous in a
dry, unconfined, non-conductive location. These voltages must be reduced if the location
is wet, confined or conductive. A simple rule is to consider all voltages above 35V either
dc or ac as potentially hazardous.
2.7.5 Trainees and other Persons with Limited Skills or Experience
Some technicians lack the necessary skills to work live and so pose a threat to their own
health as well as to others and require close supervision. Trainees and other persons so
designated must not begin live work unless supervision is available. A list of those
authorised to conduct such work is maintained and displayed in the workshop, if your
name is not on it then do not start work.
2.7.6 Place of Working
Whenever possible the preferred place of working on live equipment is the workshop.
2.7.7 Equipment
The correct test equipment must be used when working live. The equipment and probes
must be of sufficient capacity for voltage and current, and be in good condition. Where
possible high voltage probes should be attached with any electrical power removed and
charge storage devices discharged.
Protective devices should be used if possible but not be wholly relied upon (see section
on RCD Protected Outlets and Other Protective Devices).
2.7.8 Precautions
a) Consider any dangers. This will normally be done quite quickly by the individual
technician. Questions to ask yourself could consist of the following:



Can the work be done with the equipment dead?
Am I authorised to conduct live working at this potential?
Should I be accompanied by a colleague and is someone available to assist in an
emergency?
24











Is it absolutely necessary to work on or near equipment that is live at dangerous
voltage or current levels?
Have suitable precautions been taken to avoid injury?
Am I competent to carry out this work unsupervised?
Is there room to move or stand back in case of a problem or is there a risk of
being knocked by a passer by?
Is the area cluttered with perhaps bottles of chemicals?
Are you familiar with the appliance?
Are the voltages/currents excessive such as in X-Ray or Laser equipment?
Is the test equipment adequate?
Is someone available to assist in an emergency?
Could the lights be accidentally switched off by leaving you in the dark?
Does the area need to be cordoned off to prevent others from entering and risking
themselves or the person working?
b) Set in place adequate precautions to prevent danger to yourself and others. These
may include:










The use of RCD’s or isolating transformers.
The use of lockouts, barriers and signs.
The use of suitable insulation to cover dangerous terminals.
Powering the circuit from a lower voltage. EG in some electronic devices you can
by-pass the appliances built-in mains driven power supply and instead attach a
bench power supply thus eliminating the mains voltages form the device.
Be sure to familiarise yourself with the type of equipment under test. EG does it
generate high voltages internally?
Whenever possible attach probes to H.V. terminals when the equipment is dead.
Use safety glasses where a danger of arcing exists.
Do not work alone and ensure that someone is aware that you are working on live
equipment and the location and nature of the equipment. This should consist of
telling the supervisor and the person responsible for the area you are working. If
necessary work in pairs.
Do not leave exposed live terminals unattended even for a moment. If you must
leave the power on whilst not in attendance then dangerous terminals must be
adequately covered by replacing and securing the covers. Persons within the area
must be made aware of the danger by the use of signs such as ‘Danger - Electric
Shock Risk’ or ‘Danger - Live Conductors’ placed adjacent to the equipment and
where necessary kept out by the use of suitable barriers. Equipment being tested
overnight must have all their terminals securely covered and adequate warning
signs and barriers used.
If there is a chance of insufficient light in the event of a main lighting failure then
have a spare lamp operating from a local socket separate from the main lighting
circuit.
c) Ensure that the test equipment you use:
25



Is suitable for the purpose.
Is not damaged and that all protective elements are intact. EG has someone
removed the earth from the oscilloscope?
Meets required standards. Equipment purchased for your use should always meet
the required standards. You must not use your own equipment unless it has first
been approved by the supervisor.
2.8 Non-Live Working (Permanently Connected Mains Connections)
The major hazard is accidental switching on of the isolators by persons other than the
technician carrying out the work. This may be because the technician has left the area for
any reason and an individual unknowingly switches on the power to get a service running
again. The technician then assumes that the equipment is still in the same condition as
when left and is then exposed to the danger of electric shock. Further dangers include the
risk of charged capacitors.
Other non-electrical dangers are the changing of saw blades on a circular saw, changing
the head on a milling machine or chuck on a lathe etc. This type of work involves
working with the hands in and around the rotating mechanism. If the power is
accidentally applied then serious damaged can be done to the individual.
2.8.1 Precautions




Switch off the power at the isolator and lock it off with appropriate padlocks. If
more than one person is working then it is preferable that each should have their
own padlock.
Verify using an appropriate tester that the equipment is in fact dead.
Discharge any capacitors using a recognized method. Do not short with a
screwdriver.
Use appropriate notices such as ‘Danger - Men working on electrical circuits’
2.9 Working Within the Workshop
The major hazards around the workshop are injuries from rotating or other machinery;
slipping, tripping or falling; solder fumes; paint, lacquer and solvent fumes; electric
shock; burns & fire; injury through lifting.
2.9.1 Precautions





Keep walkways clear from obstructions and clear spills immediately.
Use steps or ladders to reach places above head height. Do not use stools or
chairs.
Use fume extractors whilst soldering so as to draw the solder fumes away from
the face.
Use eye, face and hand protection where a risk of damage or contamination is
possible whilst operating machinery or where a risk of explosion exists as in
changing high pressure lamps or vacuum tubes (CRT’s).
Wear eye protection when machinery such as drills or lathes are operating.
26






Keep long hair, ties ETC away from rotating machinery. Hair should be tied-up.
Ties should preferably be removed or at worst kept within the overall and tucked
into shirt. Clip-on ties can be used.
Disconnect power to machinery when changing tools ETC by locking off the
isolator with a padlock.
Dispose of sharp material appropriately, use the metal ‘swarf bins’ adjacent to the
lathes/milling machines.
Use aerosols such as butane, solvents, lacquers and paints in well ventilated areas
and not in the paint store. The paint spray booth is the designated area for spray
painting. As well as the fumes which can be harmful these are generally
flammable. An example of a risk of fire from an aerosol is the use of switch
cleaner on contacts which may arc causing sparks, allow time for the propellant to
evaporate before applying power. This could mean times up to 15 minutes in
areas with little air flow.
Before using a power tool or any portable electrical appliance check that it is in
good condition by inspecting the cable and plug for cuts, fraying or breakage.
Look for the ‘Tested’ label. Do not use it if it does not have an up-to-date ‘Tested’
label or if the cable/plug appear damaged. The criteria for an up-to-date test label
would be if the tested date is within 12 months.
Always fill gas soldering bolts in a well ventilated area and do not near any naked
flames. They should be used solely for the purpose they were bought for and not
as a cigarette lighter. They should not be carried in the pocket in case of fuel
leakage.
2.10 Lasers
Reference must be made to the Engineering Department Safety Handbook.
NO PERSONS SHALL WORK ON A LASER WITHOUT HAVING ADEQUATE
TRAINING AND/OR KNOWLEDGE.
2.11 Further Reading
Medical Electrical Equipment BS 5724 .
Introduction to Biomedical Electronics (CH2 Patient Safety) ISBN 0-07-017895-X
Protection of personnel against hazards from laser radiation BS 4803
European Laser Safety Standard BS EN 60825
IEE Code of Practice for In-service Inspection and Testing of Electrical Equipment
HSE Maintaining portable & transportable electrical equipment HSG107
HSE Safety In Electrical Testing At Work , INDG354,
2.12 Definitions
AUTHORISED PERSON: A fully qualified person authorised by the TRO, or his
nominee, to carry out specific functions.
COMPETENT PERSON: A person over the age of 18 with sufficient technical
knowledge and experience to enable him/her to avoid danger in carrying out his/her
duties.
27
EXTRA-LOW VOLTAGE: A voltage not normally exceeding 50V between
conductors, and not exceeding 30V R.M.S or 50Vdc between any conductor and earth.
LOW VOLTAGE: A voltage in a system, normally exceeding the extra-low voltage but
not exceeding 250V R.M.S whether between conductors or to earth.
MEDIUM VOLTAGE: A voltage in a system normally above 250V R.M.S., but not
exceeding 650V.
HIGH VOLTAGE: A voltage in a system , normally above 650V but not exceeding
3kV RMS.
EXTRA-HIGH VOLTAGE: A the voltage in a system normally above 3kV R.M.S.
28
3. WORKING OUTWITH THE WORKSHOP
The major problem here is unfamiliarity with the surroundings. Many areas are accessed
by us. These include chemistry labs, biological labs, animal labs, electrical labs. All of
these present us with particular hazards which must be considered.
3.1 Precautions
a) Always check with a responsible person before commencing work. If you can’t check
then do not start work. A responsible person is the TRM/TRO/Team Leader or the
person in charge of the area or apparatus. Generally an undergraduate is not
considered a responsible person.
b) Ask specifically about any hazards associated with the equipment or the area. For
instance if a label stating ‘Biological Hazard’ is apparent then ask what the
precautions are before starting work.
c) When leaving the area, even for a short period, ensure that any work unfinished is left
safe by locking off the isolator and labelled appropriately so as to prevent injury to
others. If necessary tell the responsible person.
d) When finished the work ensure everything is left in a safe condition, ensuring that all
wires are safely terminated and isolated, all covers are replaced and that where
appropriate the earth terminal is sound. The appliance should be tested for earth
continuity and insulation and labelled accordingly.
e) Notify the responsible person when the work has completed and ensure that he/she is
satisfied with the completed work.
29
4. APPENDICES
4.1 Chemicals In the Workshop
4.1.1 Introduction
Standard chemicals used in workshops can pose a potential risk to health and safety.
Hazardous chemicals should be provided with Materials Safety Data Sheets (MSDS).
These MSDS are held in the Workshop Safety Library and are freely available to study.
Before using any chemicals for the first time, instructions and precautions on the
container must be read along with the MSDS. Inexperienced personnel must receive
training in the use of chemicals or other substances which pose a hazard to health. Where
in doubt seek guidance from a supervisor or the Safety Adviser.
Exposure to hazardous chemicals most frequently occurs when:




MACHINING
WELDING
PAINTING
CLEANING AND DEGREASING
The most common health effects are:



DERMATITIS FROM METAL WORKING FLUIDS AND OILS
LUNG PROBLEMS FROM ISOCYANATE PAINTS AND GLUES
POISONINGS SUCH AS LEAD POISONING AND RARELY CANCER FROM MINERAL
OILS
To minimise hazards:









Read data sheets
Read precautions on containers
Seek advice
Avoid skin contact and inhalation
Use in well ventilated conditions using fume extraction where necessary
Wear appropriate personal protective equipment
Wear barrier cream
Wash frequently with soap and water
Dispose in accordance with manufacturers recommendations and environmental regulations.
4.1.2 Cleaning And Degreasing
Many cleaning and degreasing substances used are harmful if not used properly, either through direct skin
contact or through breathing in mist or vapour given off, commonly causing dermatitis and narcotic effects.
Some cleaners give off vapour which is easily ignited.
To minimise hazards:





Compare manufacturers data sheets and use the least harmful
Read safety data sheets
Avoid spills and evaporation by keeping lids on containers
Mark contents clearly
Wear appropriate protective equipment such as gloves, overalls, eye and foot protection to prevent
contact with fluids.
When using liquids:
30


Work in well ventilated areas and avoid working in confined spaces
Where necessary to work in a confined space special precautions are necessary and a risk
assessment required
VAPOUR DEGREASING TANKS
Using these badly may cause exposure to harmful levels of vapour which if inhaled may cause drowsiness
or in extreme cases unconsciousness. Direct contact may cause irritation and dermatitis and should never be
frequent or prolonged.
To minimise exposure:




Position tanks in an area free from draughts
Stack components inside container so that they drain properly
Allow them to dry before removing them
Use covers when not using tank
4.1.3. Metalworking Fluids
Ill health from metal working fluids, used neat or mixed with water, most commonly arises from:
a)
Skin contact during





Preparation, application and removal of fluid
Handling of workpieces
Splashing and machining
Changing and setting of tools
Maintenance and cleaning of machines
b) Breathing in aerosols, mist and fumes when machining causing irritation of the eyes, nose and
throat and occasionally breathing difficulties.
To minimise hazards:
DO






Read and follow manufacturers guidance
Top up in accordance with suppliers instructions
Keep machines clean and free from debris
Clean sumps, pipework and machines before refilling with fluids which should be mixed outside
of the machine
Wash with soap and water regularly to remove metalworking fluids
Keep oily rags out of pockets
DON’T







Wear jewellery, rings or watch straps under which fluids may collect
Use unrefined mineral oils and mildly refined distilled oils which may cause cancer and for which
safer alternatives are available.
Use fluids beyond their normal life
Allow other oils to contaminate the metalworking fluid
Allow fluids to overheat
Allow water-mix fluids to stagnate when not in use
Eat or drink in working areas
31
4.1.4 Decanted Chemicals
Some chemicals may be supplied in larger containers kept in chemical stores and decanted into small
bottles for local use. These smaller bottles or containers must be properly marked with the contents and
labelled with their particular hazards for example Flammable.
Chemicals commonly found in the workshop are listed here together with their safety data sheets on the
following pages hazards.




Acetone
Ethanol, Methanol and Propanol
Paraffin (Kerosene)
White Spirits
4.1.5 Printed Circuit Board Chemicals
Chemicals used in PCB plant are often supplied in powder, crystal or concentrated liquid form and have to
be dissolved or diluted in accordance with manufacturers instructions. Ill health from PCB chemicals, most
commonly arises from:
c)
Skin or eye contact during




Preparation of fluids
Splashes from topping up
Handling of workpieces before and after processing
Maintenance and cleaning of PCB plant
d) Breathing in fumes when processing causing irritation of the eyes, nose, throat and mouth and
could cause breathing difficulties.
To minimise hazards:
DO




Read and follow manufacturers guidance.
Top up in accordance with suppliers instructions and avoid splashes.
Use LEV and PPE including gloves, goggles and coveralls. When cleaning out and refilling
system additional PPE in the form of rubber boots, full face mask long rubber gloves should be
used.
Keep PCB plant clean and clean up any spills immediately
DON’T




Wear jewellery, rings or watch straps under which fluids may collect
Allow fluids to overheat
Put head into LEV
Eat or drink in working areas
32
4.2 Chemical Datasheets
4.2.1 Acetone
Hazards
Extremely flammable liquid and vapour. Vapour may cause
flash fire. Harmful if swallowed or inhaled. Causes irritation to skin, eyes and respiratory tract. Affects
central nervous system.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Swallowing small amounts is not likely to produce
harmful effects. Ingestion of larger amounts may
produce abdominal pain, nausea and vomiting.
Aspiration into lungs can produce severe lung
damage and is a medical emergency. Other
symptoms are expected to parallel inhalation.
Ingestion
Aspiration hazard. If swallowed, vomiting may
occur spontaneously, but DO NOT INDUCE. If
vomiting occurs, keep head below hips to prevent
aspiration into lungs. Never give anything by mouth
to an unconscious person. Get medical aid
immediately.
Skin
Irritating due to de-fatting action on skin. Causes
redness, pain, drying and cracking of the skin.
Skin
Immediately flush skin with plenty of water for at
least 15 minutes. Remove contaminated clothing
and shoes. Get medical attention. Wash clothing
before reuse. Thoroughly clean shoes before reuse.
Eyes
Vapours are irritating to the eyes. Splashes may
cause severe irritation, with stinging, tearing,
redness and pain.
Eyes
Immediately flush eyes with plenty of water for at
least 15 minutes, lifting upper and lower eyelids
occasionally. Get medical aid immediately.
Inhalation
Inhalation of vapours irritates the respiratory tract.
May cause coughing, dizziness, dullness, and
headache. Higher concentrations can produce
depression, narcosis, and unconsciousness.
Inhalation
Remove to fresh air. If not breathing, give artificial
respiration. If breathing is difficult, give oxygen.
Get medical aid.
33
4.2.2 Ethanol, Methanol And Propanol (Ethyl, Methyl And Isopropyl Alcohol)
Hazards
Flammable. Harmful if swallowed or inhaled. Causes irritation to skin, eyes and respiratory tract. Affects
central nervous system.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
May cause irritation with nausea, vomiting and
diarrhoea. May cause kidney damage. May cause
headache, dizziness, drowsiness, and nausea.
Advanced stages may cause unconsciousness and
respiratory failure.
Ingestion
If victim is conscious and alert, give 2-4 cupfuls of
milk or water. Never give anything by mouth to an
unconscious person. Get medical aid immediately.
Skin
May cause skin sensitization, an allergic reaction,
which becomes evident upon re-exposure to this
material. Prolonged and/or repeated contact may
cause de-fatting of the skin and dermatitis. May
cause irritation with pain and stinging, especially if
the skin is abraded.
Skin
Flush skin with plenty of soap and water. Get
medical aid if irritation develops or persists.
Eyes
Produces irritation, characterized by a
burning sensation, redness, tearing,
inflammation, and possible corneal injury.
Eyes
Immediately flush eyes with plenty of water for at
least 15 minutes, occasionally lifting the upper and
lower lids. Get medical aid immediately.
Inhalation
Inhalation of high concentrations may cause
headache, dizziness, unconsciousness and coma.
Inhalation of vapour may cause respiratory tract
irritation.
Inhalation
Remove from exposure to fresh air immediately. If
not breathing, give artificial respiration. If breathing
is difficult, give oxygen. Get medical aid
immediately.
34
4.2.3 Paraffin (Kerosine)
Hazards
Classified as flammable and as harmful due to the aspiration hazard. Prolonged and repeated skin contact
can lead to irritation and dermatitis.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Small amounts unlikely to cause adverse affect.
Larger amounts may cause irritation with diarrhoea
and vomiting.
Ingestion
Wash mouth out with water and give water to drink.
If a large amount has been swallowed get medical
advice. Do not induce vomiting.
Skin
Prolonged or repeated contact may cause short term
irritation, de-fatting of the skin and could result in
dermatitis.
Skin
Wash skin as soon as possible with soap and water.
Change contaminated clothing immediately and
launder before re-use. Get medical advice if
irritation persists.
Eyes
Wash out immediately with large amounts of water.
If redness or irritation persists get medical advice.
Eyes
May cause short-term irritation with redness and
stinging.
Inhalation
Remove to fresh air. Get medical advice if
symptoms persist.
Inhalation
Fumes or vapour may cause irritation to eyes and
mucous membranes, and drowsiness leading to loss
of consciousness.
35
4.2.4 White Spirits
Hazards
Flammable. Harmful: May cause lung damage if swallowed. Toxic to aquatic organism.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Soreness and redness of mouth and throat. Nausea
and stomach pain may occur. There may be
vomiting.
Ingestion
Wash out mouth with water. Do not induce
vomiting. If conscious give half a litre of water to
drink immediately. Get medical aid.
Skin
Irritation or redness of skin
Skin
Remove all contaminated clothing and footwear
unless stuck to the skin. Drench affected area in
running water for 10 minutes. Get medical aid.
Eyes
Bathe the eye with running water for 15 minutes.
Get medical aid.
Eyes
Irritation and redness, eyes may water profusely
Inhalation
Remove from exposure to fresh air immediately. If
not breathing, give artificial respiration. If breathing
is difficult, give oxygen. Get medical aid.
Inhalation
Irritation of throat with feeling of tightness in the
chest.
36
4.2.5 Printed Circuit Board Chemical Developer Solution: Sodium Metasilicate
Hazards
Harmful by inhalation or if swallowed. Inorganic substance. Avoid entry into drainage system
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Ingestion
Wash out mouth with water. Do not induce
vomiting. Get medical aid.
Skin contact
Skin
Remove all contaminated clothing and footwear.
Irrigate thoroughly with soap and water. Get
medical aid.
Eye contact
Eyes
Irrigate thoroughly with water. Get medical aid.
Inhalation
Inhalation
Remove from exposure to fresh air immediately.
Get medical aid.
37
4.2.6 Printed Circuit Board Chemical Stripper: Monoethanolamin 25%,
Butoxyethanol 65%
Hazards
Harmful by inhalation or if swallowed. Irritating to eyes and respiratory system.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Ingestion
Wash out mouth with water. Give plenty water to
drink. Get medical aid.
Skin contact
Skin
Remove all contaminated clothing and footwear.
Irrigate thoroughly with soap and water. Unless
contact is slight get medical aid.
Eye contact
Eyes
Irrigate thoroughly with water for at least 10
minutes. Get medical advice.
Inhalation
Inhalation
Remove from exposure to fresh air immediately.
Rest and keep warm. Get medical aid.
38
4.2.7 Printed Circuit Board Chemical - Ferric Chloride Hexahydrate Crystals
Hazards
May be corrosive to mucous membranes, eyes and skin. Its effects are similar to those of a caustic
substance.
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Ingestion
Wash out mouth with water. Do not induce
vomiting. Get medical aid.
Skin contact
Skin
Remove all contaminated clothing and footwear.
Wash affected area thoroughly with soap and water.
If irritation occurs and persists get medical aid.
Eye contact
Eyes
Irrigate thoroughly with water for at least 15
minutes. Get medical advice.
Inhalation
Inhalation
Remove from exposure to fresh air immediately.
Rest and keep warm. If recovery is not rapid get
medical aid.
39
4.2.8 Printed Circuit Board Chemical PC168 Immerse Tin: Thiourea 27%,
Stannous Chloride 15%
Hazards
Harmful. Hazardous to health if swallowed. Inorganic substance. Avoid entry in to drainage system
First Aid Measures
Type Of Exposure
First Aid Measures
Ingestion
Ingestion
Wash out mouth with water. Give water to drink.
Get medical aid.
Skin contact
Skin
Remove all contaminated clothing and footwear.
Wash affected area thoroughly with water.
Eye contact
Eyes
Irrigate thoroughly with water. Get medical advice.
Inhalation
Remove from exposure to fresh air immediately.
Inhalation
40