Image result for welding Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing fusion, which is distinct from lower temperature metal-joining techniques such as brazing and soldering, which do not melt the base metal.

1. Gas Cutting
&
Welding
Gas Cutting
&
Welding
PPREPARED BY
SOUMEN MAKAR
RECLAMATION AND DREDGING WORKS
BMCT/JNPT-4

3. ACETYLENE CYLINDERS
 Maroon in colour.
 Acetylene gas (C2H2) is dissolved in
acetone (liquid) and stored at 250 psi, in
a specially designed cylinder.
 Acetylene cylinders has a volume of 8.5
m3.
 Maroon in colour.
 Acetylene gas (C2H2) is dissolved in
acetone (liquid) and stored at 250 psi, in
a specially designed cylinder.
 Acetylene cylinders has a volume of 8.5
m3.

5. Valve Protection Cap
Typical Sectional view of
Valve Arrangement
Valve protection cap
Valve
Valve

6. OXYGEN CYLINDERS
 Oxygen is a colourless,
tasteless, and odourless
gas and is slightly
heavier than air.
 Oxygen cylinder is black
in colour.
 Oxygen stored at 2200
psi
 Oxygen cylinders has a
volume of 6.9 m3
 Oxygen is a colourless,
tasteless, and odourless
gas and is slightly
heavier than air.
 Oxygen cylinder is black
in colour.
 Oxygen stored at 2200
psi
 Oxygen cylinders has a
volume of 6.9 m3

7. CYLINDER STORAGE
 Well ventilated room
 No open flame in the store
 10 m distance from oxygen and acetylene
cylinders
 No materials that are prone spontaneous
combustion
 Should not be stored in direct sunlight.
 Well ventilated room
 No open flame in the store
 10 m distance from oxygen and acetylene
cylinders
 No materials that are prone spontaneous
combustion
 Should not be stored in direct sunlight.

8. CYLINDER STORAGE
Inflammable Gas

9. CYLINDER STORAGE
FullEmpty
Min. 10’
Min.10’
Full CylindersEmpty Cylinders Fuel GasOxygen
 Cylinders containing oxygen shall be stored separate from
cylin­ders fuel-gases.
 Minimum 10 feet distance shall be maintained between the storage
areas.

10. Accessories

11. Regulators

12. UNLOADING FROM TRUCK
Never drop
Use wooden Ramp and coir matters (50cm
thick)
Keep the top of the cylinder up
 Roll the cylinder keeping it upright
Never drop
Use wooden Ramp and coir matters (50cm
thick)
Keep the top of the cylinder up
 Roll the cylinder keeping it upright

13. Lifting cylinders by crane
Use of cradle
4-leg bridle sling
D-shackle and lifting lug

14. Use of Cylinder trolley
Shifting cylinders at site
Avoid Rolling & Manual
carrying
Use trolley

15. Keep the cylinder upright and away from
hot jobs.
Fix the DA and oxygen regulator to the
respective cylinders after ensuring free
from dirt or grease.
Connect the cutting hoses to the regulators
and cutogen with hose clamps.Blue or black
hoses for oxygen and red for DA.
RIGHT OPERATION
Keep the cylinder upright and away from
hot jobs.
Fix the DA and oxygen regulator to the
respective cylinders after ensuring free
from dirt or grease.
Connect the cutting hoses to the regulators
and cutogen with hose clamps.Blue or black
hoses for oxygen and red for DA.

16. Open the cylinder and check for leakage by
soap water test at the joints.The same to be
followed for the oxygen cylinder.Close the
cylinders .
Purge the oxygen line and then the DA line
one after the other and close the valves.
RIGHT OPERATION
Open the cylinder and check for leakage by
soap water test at the joints.The same to be
followed for the oxygen cylinder.Close the
cylinders .
Purge the oxygen line and then the DA line
one after the other and close the valves.

17. Open the DA regulator,the torch valve and
light the gas. Then open the oxygen valves
to the required pressure.
After cutting start closing from oxygen and
then DA.
RIGHT OPERATION
Open the DA regulator,the torch valve and
light the gas. Then open the oxygen valves
to the required pressure.
After cutting start closing from oxygen and
then DA.

18. CUTTING NOZZLES
Max. Materials
thickness,
(MS in mm)
Size of
nozzle
Cutting oxygen
pressure in
kg/cm2
12
25
50
75
100
150
200
250
300
1/32”
3/64”
1/16’
1/16’
1/16”
5/64”
3/32”
7/64”
1/8”
1.4
3.0
4.0
4.0
5.0
5.5
7.5
8.0
8.0
12
25
50
75
100
150
200
250
300
1/32”
3/64”
1/16’
1/16’
1/16”
5/64”
3/32”
7/64”
1/8”
1.4
3.0
4.0
4.0
5.0
5.5
7.5
8.0
8.0

19. HAZARDS
 FLASH BACK.
 BACK FIRE.
 GENERAL FIRE.
 EXPLOSION.
 FLASH BACK.
 BACK FIRE.
 GENERAL FIRE.
 EXPLOSION.

20. FLASH BACK
 RETROGRESSION OF THE FIRE UPTO THE
CYLINDER.
BACK FIREBACK FIRE
RETROGRESSION OF THE FIRE IN THE
CUTOGEN.

21. When the blow pipe becomes hot.
Nozzle blocked.
Nozzle close to the job.
Job close to the ground.
Pressure difference between flame pressure
and the hose pressure.
REASONS
When the blow pipe becomes hot.
Nozzle blocked.
Nozzle close to the job.
Job close to the ground.
Pressure difference between flame pressure
and the hose pressure.

22. IF A BACK FIRE OCCURS
 The blowpipe valves shall be shut off,
oxygen first and then the fuel gas;
 Oxygen and fuel gas cylinder valves shall be
shut off;
 The blowpipe shall be cooled with water, if
necessary;
 The equipment shall be checked for damage
or faults, particularly the nozzle.
 The blowpipe valves shall be shut off,
oxygen first and then the fuel gas;
 Oxygen and fuel gas cylinder valves shall be
shut off;
 The blowpipe shall be cooled with water, if
necessary;
 The equipment shall be checked for damage
or faults, particularly the nozzle.

23. IF A FLASH BACK OCCURS
 Cylinder valves of both fuel gas and oxygen
shall be closed immediately.
(If it is safe to do so.)
 Replace damaged Hoses, Blow pipe, Flash
back arrestors & regulators before reuse.
 Cylinder valves of both fuel gas and oxygen
shall be closed immediately.
(If it is safe to do so.)
 Replace damaged Hoses, Blow pipe, Flash
back arrestors & regulators before reuse.

24. FLASH BACK PREVENTION
 Purge hose pipes before lighting.
 Only Spark igniters shall be used to ignite
 Flashback arresters shall be provided at both
ends of the hoses to prevent backflow of gas
towards cylinders.
 Correct gas pressure and for the nozzle size
shall be used.
 Purge hose pipes before lighting.
 Only Spark igniters shall be used to ignite
 Flashback arresters shall be provided at both
ends of the hoses to prevent backflow of gas
towards cylinders.
 Correct gas pressure and for the nozzle size
shall be used.

25. FIRE ON CYLINDER
 Close the valve
 Try to extinguish the fire.
 Detach the regulator
 Immerse the cylinder in water or apply water
copiously at the bottom half of the cylinder.
 Open the valve and keep it the cool water till it
becomes empty
 Do not stand in the direction of fusible safety valve
fixed at the bottom of the cylinder.
 Close the valve
 Try to extinguish the fire.
 Detach the regulator
 Immerse the cylinder in water or apply water
copiously at the bottom half of the cylinder.
 Open the valve and keep it the cool water till it
becomes empty
 Do not stand in the direction of fusible safety valve
fixed at the bottom of the cylinder.

26. EXPLOSION
Reasons:
Fire on cylinder (pouring water on hot
cylinder)
Cylinder exposed to external heat
Rough handling
Reasons:
Fire on cylinder (pouring water on hot
cylinder)
Cylinder exposed to external heat
Rough handling

27. Helmets with face shields
Black glass - din value 4 to 5
Leather gloves
Leather apron
Safety shoes
PPE
Helmets with face shields
Black glass - din value 4 to 5
Leather gloves
Leather apron
Safety shoes

28. SAFETY IN WELDINGSAFETY IN WELDING

29. BASIC ELEMENTS
OF
WELDING
BASIC ELEMENTS
OF
WELDING

31. SAFETY IN WELDING
 The body of the welding machine should
be earth.
 The terminals of the welding cables
should be provided with lugs and kept
tight.
 The body of the welding machine should
be earth.
 The terminals of the welding cables
should be provided with lugs and kept
tight.

32. SAFETY IN WELDING
 The joints in the cables should be made
with terminals, kept tight and well
insulated with heat resistant tape.
 The cable should be free from joints
atleast for a length of three meters from
electrode holder to avoid shock hazard.
 The joints in the cables should be made
with terminals, kept tight and well
insulated with heat resistant tape.
 The cable should be free from joints
atleast for a length of three meters from
electrode holder to avoid shock hazard.

33. SAFETY IN WELDING
 Other electrical cables should not be
kept laid with welding cables, to avoid
insulation damage.
 For the return lead only proper cable
should be used. Using rods, angles,
channels etc. Should be avoided.
 Other electrical cables should not be
kept laid with welding cables, to avoid
insulation damage.
 For the return lead only proper cable
should be used. Using rods, angles,
channels etc. Should be avoided.

34. SAFETY IN WELDING
 Never change electrode with bare hands
or wet gloves, when standing on wet
floors.
 Never change electrode with bare hands
or wet gloves, when standing on wet
floors.

35. HAZARDS
 Fire
 Shock
 Health hazards
 Fire
 Shock
 Health hazards

36. HEALTH HAZARDS
 Exposure to various toxic gases generated
during welding may produce one or more of the
following effects:
 Inflammation of the lungs (chemical phenmonitis)
 Pulmonary edema (swelling and accumulation of
fluids)
 Chronic bronchitis.
 Asphyxiation.
 Exposure to various toxic gases generated
during welding may produce one or more of the
following effects:
 Inflammation of the lungs (chemical phenmonitis)
 Pulmonary edema (swelling and accumulation of
fluids)
 Chronic bronchitis.
 Asphyxiation.

37. OCCUPATIONAL EXPOSURE STANDARDS
RELATING TO WELDING FUME CONSTITUENT
OES
CHEMICALS LONG TERM SHORT TERM
Aluminum oxide 10 mg/m3
Cadmium 0.05 mg/m3 0.05 mg/m3
Chromium III 0.5 mg/m3
VI 0.05 mg/m3
Copper 0.2 mg/m3Copper 0.2 mg/m3
Fluoride 2.5 mg/m3
Iron 5 mg/m3
Lead 0.15 mg/m3
Manganese 5 mg/m3
Nickel (insoluble) 0.5 mg/m3
( Soluble) 0.1 mg/m3
Ozone 0.1 PPM 0.3 PPM
Welding fume 5 mg/m3

38. FACTORS TO BE CONSIDERED IN
ASSESSMENTS
Welding position
Welding location
Duration of exposure
FACTORS TO BE CONSIDERED IN
ASSESSMENTS
Welding position
Welding location
Duration of exposure

39.  Elimination or substitution
Modification of the process or
engineering
Local exhaust ventilation
General dilution ventilation
Personal protective equipment
Preventive Measures
 Elimination or substitution
Modification of the process or
engineering
Local exhaust ventilation
General dilution ventilation
Personal protective equipment

40.  FACE SHIELD WITH ATTACHED HELMET
 EYE
 GOGGLES, FACE-SHIELD.
 DIN VALUE OF BLACK GLASS 12 to 14 .
 HAND
 LEATHER HAND GLOVES (FLAME
RESISTANT)
 BODY
 LEATHER APRON & LEG GAURD.
 FOOT
 SAFETY SHOE.
Personal Protective Equipment
 FACE SHIELD WITH ATTACHED HELMET
 EYE
 GOGGLES, FACE-SHIELD.
 DIN VALUE OF BLACK GLASS 12 to 14 .
 HAND
 LEATHER HAND GLOVES (FLAME
RESISTANT)
 BODY
 LEATHER APRON & LEG GAURD.
 FOOT
 SAFETY SHOE.

41. HAZARDS AT SITE
 Working overhead.
 Working in confined spaces.
 Welding or cutting tanks or vessels.
 Tripping hazards.
 Working overhead.
 Working in confined spaces.
 Welding or cutting tanks or vessels.
 Tripping hazards.

42. Thank UThank U