TEST PROCEDURE
PRIOR TO WELDING, CUTTING OR DRILLING PONTOON
POTENTIAL HAZARD
:
Marsh Master pontoons are sealed chambers, and the possibility for an
explosive mixture to be present exists. This mixture can be caused by a generation of methane
gas or a fuel such as gasoline or diesel fuel entering the pontoon through a crack.
IT IS IMPERATIVE THAT THE PONTOON BE CHECKED
FOR EXPLOSIVE ATMOSPHERE PRIOR TO WELDING,
CUTTING, OR DRILLING THE PONTOONS!!!!
STEP 1: Remove the drain plug from the pontoon. It is located between the #7 and #8 outside bogey wheels.
A small amount of water (<1 gallon) may drain from the pontoon. It is normal for a small amount of
water to form due to condensation in the pontoons.
STEP 2: Using an ATX612 Multi-Gas Monitor or equal, insert the gas pick up tube at least 6 inches into the
drain opening in the pontoon. Avoid getting any water into the pickup tube as water can damage the
instrument.
Note:
The Gas Monitor instrument must be “bump” tested before each use. It must also be calibrated
monthly. The person using the instrument must be trained in the use of the instrument. If there is
any question concerning the instrument, contact the instrument manufacturer or
Hagemeyer/Vallen, our local supplier, at 225-673-5670.
STEP 3: Turn the instrument on and take a reading. The instrument will alarm at 10 % LEL (lower explosion
limit). If you get an alarm or a reading above 2 percent LEL, go to Step 4. If you get a reading of 0 or
1, the pontoon is safe to weld, cut, or drill. Keep the instrument running at all times when welding.
THE HEAT FROM WELDING CAN GENERATE GAS
FUMES. STOP WELDING IMMEDIATELY IF YOU GET AN
ALARM, AND GO TO STEP 4.
STEP 4: Purge the pontoon with air as follows. Insert an air hose into the pontoon through the drain opening.
Slowly bleed air into the pontoon allowing the pontoon to purge. After 1 hour of purging, test again.
If you get a reading above 2 percent LEL, try purging another hour and test again. If you cannot get a
low enough reading by purging this way, proceed to Step 5.
STEP 5: Remove the tracks and top slides from the machine. Removing the top slides will give you 16 bolt
hole openings in the top of the pontoon to bleed through. Connect an air hose with a regulator and
shut-off valve to the drain port of the pontoon. Slowly bleed air into the pontoon so that it comes
out of the top bolt holes. Make sure the pressure in the pontoon does not exceed 2 psi. Purge for
several hours, and then retest LEL. Purge as necessary to obtain a reading of 0 to 1 LEL. When you
obtain a safe reading of less than 1 percent LEL, the pontoon is safe for welding, drilling, or cutting.
Be sure to keep the instrument connected and running when welding.
WARNING!
SERIOUS INJURY CAN OCCUR!
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WARNING!
SERIOUS INJURY CAN OCCUR!
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