This presentation contains safety practices to be followed by technicians while working on a job. The slides do not contain engineering details of the equipment or ISO , NFCA standards

1. SAFE PRACTICES WHILE WELDING, GAS
CUTTING, DRILLING AND GRINDING
Made By – Mohammad Kashif

2. GAS CUTTING
Oxy-fuel welding (commonly called oxyacetylene
welding, oxy welding, or gas welding in the U.S.)
and oxy-fuel cutting are processes that use fuel
gases and oxygen to weld and cut metals,
respectively. French engineers Edmond Fouché and
Charles Picard became the first to develop oxygen-
acetylene welding in 1903. Pure oxygen, instead of
air, is used to increase the flame temperature to allow
localized melting of the work piece material (e.g.
steel) in a room environment. A common propane/air
flame burns at about 2,000 °C (3,630 °F), a
propane/oxygen flame burns at about 2,500 °C
(4,530 °F), and an acetylene/oxygen flame burns at
about 3,500 °C (6,330 °F)

3. GAS CUTTING
Regulator- controls
pressure from tank to the
required pressure in the
hose. Then operator
controls the flow using
needle valve.
Gas hoses – they are
specifically color coded
for use.
Torch – there are two
different types of torch for
welding and cutting
purpose.

4. Regulators – they are
used to regulate the
output pressure. There
are 2 gauges one shows
the cylinder pressure
other the o/l pressure.
Check valve – it is
designed to allow gas to
flow in one direction.
Flashback arrestor – it
prevents the shock wave
from downstream
coming back up the
hoses and entering the
cylinder.

5. SAFE PRACTICES PERTAINING TO GAS CUTTING
Gas cylinder must be
prevented from sharp
impact with one another
or the ground.
Acetylene cylinder must
always be kept upright.
Cylinders should be
stored in a well
protected, well ventilated
dry location, well away
from highly combustible
material

6. Moving cylinders
Never use gas without
proper pressure regulators
One should not smoke
where cylinders are stored
Cylinder valves should
be closed after
completion of work
Do not tamper with
number and marking on
cylinder
Keep all cylinders chained,
they should be chained
individually and not as
group

7. Before connecting the
pressure regulator to a
cylinder valve, the valve
should be opened
slightly and closed. This
is called cracking and is
done to remove dirt.
To test for leak soap
solutions should be
used.
Never attempt to mix
gases in a cylinder

8. GAS TORCH AND TIPS
Never use a gas torch
as a hammer or a
lever.
A spanner and not a
plier should be used
for changing tips.
The slag accumulated
at the blow pipe should
be frequently removed
by either hard wood
stick or brass wire.

9. HOSE AND GAS TUBINGS
Use the correct color
hose for oxygen(green/
black) and acetylene
(red).
Always protect hose
from being trampled
upon.
If dirt goes into the hose
blow through (using O2
not C2H2 ) before
connecting to valve and
regulator.

10. FIRE HAZARDS
Damaged insulation can
cause local arcing between
cables and near by grounded
metal.
Sparks, molten metal gobules
and hot slag falling on
flammable material lying in
weld /cutting area.
Leaking valves on fuel gas
cylinders and blow pipes.
Back fire from blow pipes.
To work around the above
conditions fire extinguishing
equipment should be
maintained in a state of
readiness.

11. OTHER GENERAL PRECAUTIONS
Remove any combustible
material before starting
welding.
Do not weld in confined
spaces without adequate
ventilation or individual
respiratory equipment.
When welding inside boiler
cylinders must be kept
outside and hose and its
attachment tested for
leakage.
Keep a fire extinguisher
ready for emergency use.
Use goggles with non
flammable lenses and
frames.
Do not weld painted or
galvanized surfaces in a
badly ventilated place.
Never attempt to relight a
blow pipe that has blown
out without first closing both
the valves.
If cutting is to be stopped
for a long time, close the
cylinder valves and then
release all gas pressure
from the regulator by
opening torch valves
momentarily

12. ARC WELDING BASICS
Arc welding is a type of
welding that uses a
welding power supply to
create an electric arc
between an electrode
and the base material to
melt the metals at the
welding point. They can
use either direct (DC) or
alternating (AC) current,
and consumable or non-
consumable electrodes

13. WELDING MACHINES
In welding the Voltage is
directly related to the arc
length and Current is related
to amount of heat input.
Constant current machines
are generally used for
manual welding as voltage
may change due to arc
length but power given wont
change.
Positive charged anode has
more heat concentration so
for consumable electrode
DCEP gives deeper
penetration and greater weld
speed as electrode will burn
off quickly

14. PRECAUTIONS DURING USING WELDING M/C
When no welding is
being performed remove
electrode from holder
and machine must be
disconnected from
power source.
Do not change the
polarity switch when
machine is under load.
The arching due to high
current can burn the
contact switches.
Never strike an arc on a
compressed gas
cylinder.

15. ELECTRODE HOLDER
They should be of
adequate rating for the
maximum welding
current.
Electrode holder shall be
provided with discs or
shields to protect the
hands of the welder from
heat of the arc.
Hot electrode holders
must not be permitted to
dip in the water because
retaining moisture may
cause an electric shock.

16. WELDING CABLES
They should be
completely insulated and
flexible type.
The cable should be free
from repair or splices up
to 3 mtr from the
electrode holder.
Welding cable should be
kept dry and free from
grease and oil to avoid
premature breakdown of
insulation

17. SAFETY RECOMMENDATIONS IN WELDING AND
CUTTING OPERATION
One should not look at
an electric arc with the
naked eye. Use a hand
shield or helmet.
Eye trouble caused by
arc flashes may be
soothed by bathing
with the following
solution
Na2 CO3 343 g
Purified water freshly
boiled & cooled
1000 ml

18. Welder should not leave
the electrode holder on
the table or in contact
with a grounded metallic
surface.
Adequate ventilation
should be there while
welding.
Welding should not be
carried out in closed
containers or on
containers that have
held combustible
material.

19. PROTECTION FROM WELDING RAYS
Welding arc, in addition to
being very bright, is a
source of infrared and ultra
violet radiation also;
consequently the operator
must use either a helmet or
a hand shield fitted with
special filter glass.
Exposing the eyes & face to
infra red rays would lead to
the face becoming
uncomfortably hot and it
might induce serious eye
troubles. Excess UV light
can cause an affect similar
to sun burn on the skin

20. PROTECTIVE CLOTHING
Gloves protect the hand of
a welder.
For overhead welding,
some form of protection for
the head is required.
Leather skull cap or
peaked cup will do the
needful.
Leather jackets and
leather leggings are also
available.
Safety boots are
necessary to protect the
feet of the welder from hot
slag and in particular, from
falling off cuts.

21. VENTILATION & HEALTH PROTECTION
Fumes are produced
• At the arc in metal arc
welding with covered
electrodes and in arc
cutting
• When the being arc
welded is galvanized.
Fumes are very injurious to
health due to fluoride or
high chromium content.
So either work outdoor or
keep a ventilator while
working

22. VENTILATION & HEALTH PROTECTION
Gases are present at the
place of welding as a
result of
• Application of heat to
certain metals.
• Combustion (CO), the
absorption of O2 in the
process of combustion,
and the oxidation of N2 in
the air.
• The escape of gases
used for combustion in
welding and cutting
blowpipes.

23. DRILLING
Drilling is a cutting
process that uses a drill bit
to cut or enlarge a hole of
circular cross-section in
solid materials. The drill bit
is a rotary cutting tool,
often multipoint. The bit is
pressed against the work
piece and rotated at rates
from hundreds to
thousands of revolutions
per minute. This forces the
cutting edge against the
work piece, cutting off
chips (swarf) from the hole
as it is drilled.

25. SAFETY MEASURES WHILE DRILLING
Do not support the work
pieces by hand, use a
holding device.
Never make any
adjustment when the
machine is running.
Never clean away chips
using hands use a brush.
Keep all loose clothing
away from turning tools.
Ease up on the feed as the
drill breaks through the
work to avoid damaged
tools or workplaces
Always wear eye protection
while operating any drilling
machines.
Make sure that cutting tools
are running straight before
starting the operation.
Drill bit should be of correct
size

26. GRINDING
Grinding is an abrasive machining
process that uses a grinding wheel as
the cutting tool.
Grinding practice is a large and diverse
area of manufacturing and tool making.
It can produce very fine finishes and
very accurate dimensions; yet in mass
production contexts it can also rough out
large volumes of metal quite rapidly. It is
usually better suited to the machining of
very hard materials than is "regular"
machining (that is, cutting larger chips
with cutting tools such as tool bits or
milling cutters), and until recent decades
it was the only practical way to machine
such materials as hardened steels.
Compared to "regular" machining, it is
usually better suited to taking very
shallow cuts, such as reducing a shaft’s
diameter by half a thousandth of an inch
or 12.7 um.

27. SAFETY PRECAUTIONS WHILE USING PORTABLE
GRINDER
Guard must be adjusted to
protect the user.
Ensure that the machine will
not operate when
unattached by checking the
dead man switch.
Wear safety glasses or
shield to protect from flying
chips.
Do not use wheels that are
cracked or vibrating
excessively.
Use both hand while using
the grinder.