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6122
Appendix T5 Control of
Physical Hazards Associated with Use of
Compressed Gases in Welding |
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1.0
Compressed
Gas Safety:
Detailed
instructions for the safe use of compressed
gas cylinders can be found in ES&H Manual Chapter 6150 Compressed Gases.
Special instructions for welding
applications are listed here.
2.0
Compressed Gas Cylinder Storage and
Handling
· Keep gas cylinders far enough away from the actual welding or cutting operation so that they are protected from slag, sparks, flame, or electrical current.
·
Securely chain equipment to
prevent falling.
·
Store away from flammable and
combustible
materials.
·
Store extra gas and oxygen
cylinders separately.
·
Use fuel gases in the upright
position.
·
Close cylinder valves
whenever the welding
or cutting equipment is not attended.
·
Valves are to be hand
tightened only. NEVER use a hammer or a
wrench to open a valve fitted with hand wheels.
You will damage the cylinder and may cause a leak of gas into the work
area.
·
Only approved regulators may
be used. NOTE: regulators must be used only for the gas and
pressures for which they are labeled.
·
Protective caps or regulators
should be kept in place.
·
Roll cylinders on bottom
edges to move--Do not drag.
·
Manifolds must be approved by
Environmental, Safety, Health, and Quality (ESH&Q) Industrial Safety
Representative
3.0
General Gas Welding Safety Tips
·
Properly label all gas
cylinders with the gas used: for example, never refer to oxygen as “air”, and
never refer to the fuel gas by a common name – specify the name of the fuel
gas.
·
Inspect equipment for leaks
at all connections using approved leak-test solution.
·
Inspect hoses for leaks and
worn places: use liquid leak detectors on the setup before use.
·
Protect hoses and cylinders
from sparks,
flames and hot metal.
·
Use a flint lighter to ignite
the flame.
·
Stand to the side (away from
the regulators) when opening cylinder valves.
·
Open cylinder valves very
slowly to keep sudden high pressures from exploding the regulators.
·
Only open the acetylene
cylinder valve 1/4 - 3/4 turn; leave wrench in place so the cylinder can be
quickly closed in an emergency.
·
Open high-pressure
cylinders fully to prevent leakage around the valve stem
· Open and light acetylene first, then open and adjust oxygen to a neutral flame.
·
Close the acetylene torch
valve first when shutting off the torch (a “pop” might occur as the oxygen
“blows out” the flame, but this eliminates the possibility of the flame burning
up the acetylene line).
·
When finished, close cylinder
valves, bleed the lines to take pressure off regulators, neatly coil hoses and
replace equipment.
·
Have a fire extinguisher
easily accessible at the welding site
4.0
Hose and Hose Connections
·
Hoses for oxyfuel gas
service must comply with the Rubber Manufacturer's Association IP-7 Specification
for Rubber Welding Hose
·
Hoses are color coded:
green for oxygen, red for fuel gas
·
Taping of hoses: when
parallel lengths of oxygen and fuel gas are taped together to prevent tangling,
no more than 4 inches in each 12 inches may be covered by tape
·
Check with the
Industrial Safety representative for questions regarding hose connection
specifications
·
Purge hoses before
lighting the torch for the first time each day
·
Check hoses for cracks
and leaks regularly: the connection points at the regulator and torch connections
are most prone to cracking.
· Use approved backflow preventers and flashback preventers
5.0
Oxygen Cylinders
A special procedure for oxygen cylinders is required to ensure that oxygen at high pressure is not suddenly applied to the regulator. This could cause ignition of the regulator and injury to the operator. After the regulator is attached:
1.
Engage the adjusting screw
and open the downstream line to drain the regulator of gas
2.
Disengage the adjusting screw
and open the cylinder valve slightly so that the regulator cylinder pressure
gauge pointer moves up slowly before opening the valve all the way
3.
Stand to one side of the
regulator and not in front of the gauge faces when opening the cylinder valve.
4.
Gauges used for oxygen
service must be marked USE NO OIL
6.0
Oxygen prohibited use:
·
Oxygen may not be
used for:
o
ventilation
o Substitute for compressed air
o
In pneumatic tools
o
Blow out pipelines
o
Clean off clothing or work
area
o
Not be allowed to
contact oily surfaces, greasy clothing, fuels
7.0
Acetylene Cylinders
·
Acetylene must be not be used at a pressure in excess of 15 psig. Acetylene can decompose explosively above
this pressure.
·
If a leak is detected around the valve stem, close the valve and
move the cylinder outside.
o
Tighten the packing nuts.
o
If still leaking – Post the area as a fire hazard and notify
ESH&Q Industrial Safety Representative
·
In case of a cylinder fire:
o
close the valve
o
attempt to extinguish the fire with a fire extinguisher
o
If the fire extinguishes, immediately notify ESH&Q and the
supervisor
o
If the fire does not extinguish:
§
Evacuate the area
§
Sound the fire alarm
8.0
References
NFPA 51 B Standard
for Fire Prevention in use of Cutting and Welding Processes
29 CFR1910.25
NIOSH Safety
Checklist Welding, Cutting, and Brazing-General Requirements Self-Inspection
Checklist
ANSI Z87. Practice
for Occupational and Educational Eye and Face Protection
ANSI/AWS F2.2 Lens
Shade Selector.
Rubber Manufacturer's
AssociationIP-7 Specification for Rubber Welding Hose
ES&H Manual Chapter 6160 Confined Space Entry
ES&H Manual Chapter 6630 Respiratory Protection
ES&H Manual Chapter 6150 Compressed Gases
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ISSUING
AUTHORITY |
APPENDIX
AUTHOR |
APPROVAL
DATE |
EFFECTIVE
DATE |
EXPIRATION
DATE |
REV. |
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ESH&Q Division |
04/12/05 |
04/12/05 |
04/12/08 |
0 |
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