OXYGAS CUTTING OPERATIONS
Before you begin a cutting operation with an oxygas
cutting torch, make a thorough inspection of the area.
Ensure that there are no combustible materials in the
area that could be ignited by the sparks or slag produced
by the cutting operation. If you are burning into a wall,
inspect the opposite side of the wall, and post a fire
watch as required.
Setting up the oxygas equipment and preparing for
cutting must be done carefully and systematically to
avoid costly mistakes. To ensure your own safety, as
well as the safety of your coworkers and equipment,
make sure the following steps are taken before any
attempt is made to light the torch:
l Secure the cylinders so they cannot be accidently
knocked over. A good way to do this is to either put them
in a corner or next to a vertical column and then secure
them with a piece of line. After securing the cylinders,
remove the protective caps. Cylinders should never be
secured to a structural member of a building that is a
l Standing to one side, crack each cylinder valve
slightly and then immediately close the valve again. This
blows any dirt or other foreign matter out of the cylinder
valve nozzle. Do not bleed fuel gas into a confined area
because it may ignite. Ensure the valves are closed and
wipe the connections with a clean cloth.
c Connect the fuel-gas regulator to the fuel-gas
cylinder and the oxygen regulator to the oxygen
cylinder. Using a gang wrench, snug the connection nuts
sufficiently to avoid leaks.
l Back off the regulator screws to prevent damage
to the regulators and gauges and open the cylinder
valves slowly. Open the fuel-gas valve only one-half
turn and the oxygen valve all the way. Some fuel-gas
cylinders have a handwheel for opening the fuel-gas
valve while others require the use of a gang wrench or
T-handle wrench. Leave the wrench in place while the
cylinder is in use so the fuel-gas bottle can be turned off
quickly in an emergency. Read the high-pressure gauge
to check the contents in each cylinder.
l Connect the RED hose to the fuel-gas regulator
and the GREEN hose to the oxygen regulator. Notice the
left-hand threads on the fuel-gas connection.
l To blow out the oxygen hose, turn the regulator
screw in (clockwise) and adjust the pressure between 2
and 5 psig. After the hose has been purged, turn the
screw back out again (counterclockwise) to shutoff the
oxygen. Do the same for the fuel-gas hose, but do it
ONLY in a well-ventilated place that is free from sparks,
flames, or other possible sources of ignition.
. Connect the hoses to the torch. The RED
(fuel-gas) hose is connected to the connection gland
with the needle valve marked FUEL. The GREEN
(oxygen) hose is connected to the connection gland with
the needle valve marked OXY.
l With the torch valves closed, turn both regulator
screws clockwise to test the hose connections for leaks.
If none are found, turn the regulator screws
counterclockwise and drain the hose by opening the
Q Select the correct cutting tip and install it in the
cutting torch head. Tighten the assembly by hand, and
then tighten with your gang wrench.
l Adjust the working pressures. The fuel-gas
pressure is adjusted by opening the torch needle valve
and turning the fuel-gas regulator screw clockwise.
Adjust the regulator to the working pressure needed for
the particular tip size, and then close the torch needle
valve. To adjust MAPP gas, you should set the gauge
pressure with the torch valves closed. To adjust the
oxygen working pressure, you should open the oxygen
torch needle valve and proceed in the same manner as
in adjusting the fuel-gas pressure.
In lighting the torch and adjusting the flame, always
follow the manufacturers directions for the particular
model of torch being used. This is necessary because the
procedure varies somewhat with different types of
torches and, in some cases, even with different models
made by the same manufacturer.
In general, the procedure used for lighting a torch is
to first open the torch oxygen needle valve a small
amount and the torch fuel-gas needle valve slightly
more, depending upon the type of torch. The mixture of
oxygen and fuel gas coming from the torch tip is then
lighted by means of a spark igniter or stationary pilot
NEVER use matches to light the torch; their
length requires bringing the hand too close to
the tip. Accumulated gas may envelop the hand
and, upon igniting, result in a severe burn. Also,
never light the torch from hot metal.