16. WELDING AND FLAME CUTTING
Use of flame-cutters
Gas flame welding and allied processes produce fumes and gases, which may be harm-
ful to your health. Nitrogen oxides produced in heat may cause serious respiratory
symptoms if there is not enough ventilation. Local spot exhaust ventilation is a good
way to arrange ventilation.
Before lighting your torch
Make sure you have taken care of local exhaust ventilation, sufficient general ventilation
and any other means, if needed.
When the hoses are released from the valves or the torch from the hoses, there is a risk
of an explosive gas mixture of acetylene and air or oxygen. Flush the hoses by letting
acetylene or propane flow from the torch (for 10 - 30 seconds, with smaller torches the
time is longer) to the open air before you light the torch always in the following cases:
1. When the pressure regulator (with its hoses) is fitted to the cylinders or
distribution network.
2. When the valves of the cylinders or distribution manifold have been close
during a break and you have re-opened them to continue the work.
Lighting the torch
1. Open the acetylene valve of the torch.
2. Ignite the gas.
3. Open the oxygen valve to adjust the flame.
4. Test the accuracy of the flame by opening the cutting oxygen jet just
for a moment (cutting torch).
Turning off the torch
1. Close the acetylene valve.
2. Close the oxygen valve.
3. Close the valves in the distribution network or cylinders (for breaks
and after your working day).
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