a. Always open cylinder valves slowly to allow a gradual pressure build-up and to prevent diesel effect in the line or regulator.
b. Always keep cylinders away from hot work areas so that sparks, slag or flames will not reach them.
c. Always store cylinders, both full and empty, in a manner that prevents their being knocked over.
d. Always keep valve protection caps in place and hand tight, except when in use or connected for use.
e. Always clear the cylinder valve connections of any dirt particles by briefly opening and closing the valves before connecting regulators. Do not stand in direct line of a cylinder valve when opening it.
f. Always purge manifolds in a similar manner before connecting regulators.
g. To lessen the chance of rupturing the diaphragm, always ensure that the regulator adjusting screw is backed out all the way before opening bottle valve.
h. Always remove faulty regulators from service. The following symptoms indicate a faulty regulator:
1) External leaking.
2) Excessive creep in delivery pressure with the downstream valve closed.
3) Faulty gauge (if the gauge pointer does not move off the stop pin when pressurized or does not return to the stop pin after the pressure is bled off).
Additionally, the following general rules must be observed:
a. Check identification tags for proper gas.
b. Avoid storing cylinders in heavy traffic areas, such as near access or gangways of vessels.
c. Do not store cylinders in unventilated enclosures.
d. Secure all cylinders that are not actually in use in designated storage racks.
e. Protect hoses from damage due to sharp edges, sparks, slag and open flame.
f. Examine hoses regularly for leaks, wear and loose connections. Use non-ionic soap suds or a proper liquid leak detector.
g. Ensure that all compressed gas cylinders are within the hydrostatic test date.
h. To prevent a set in the diaphragm, always back the regulator adjusting screw out all the way before placing it into storage.
i. The diving tender must pay close attention to the gas pressures and change out cylinders when cylinder pressure drops to within 100 psi of the overbottom pressure. This will prevent damage to the torch and possible diver injury.
D-11.1.3 General Oxygen Precautions. The following oxygen precautions must be observed:
a. Avoid electrical circuit contact with cylinders, including electrical wires or welding circuits. They can produce short circuit arcs that can lead to a very serious accident.
b. Oxygen cylinders, valves, regulators, hoses, fittings and other apparatus shall not be handled with oily hands, gloves or greasy materials.
c. Never allow a jet of oxygen to strike an oily surface, greasy clothes or enter a fuel tank which contains or has contained a flammable substance.
d. Never use oxygen as a substitute for compressed air or a source of pressure.
e. Under no circumstances are air hoses to be used in oxygen systems of any kind.
f. Do not store oxygen cylinders gauges or fittings where they may become fouled with oil or grease.
g. Store oxygen cylinders separately from fuel gases.
D-11.1.4 General MAPP Gas Precautions. MAPP gas is a colorless, odorless combustible fuel gas. Like all fuel gases which are odorless by nature, a chemical has been added to aid in detecting leaks by smell. Like any other combustible gas, MAPP gas forms explosive mixtures with air or oxygen. The following precautions must be observed:
a. During set-up procedures, point the MAPP gas valve outlet away from the oxygen cylinder before cracking to clear the valve connections.
b. When MAPP gas lines are being purged, do not permit open lights or other sources of ignition in the vicinity of uncapped openings.
c. Do not use copper connections or fittings with MAPP gas. There is a slight possibility that MAPP gas may react with copper to produce explosive acetylides when the gas is under high pressure.
d. Never use a match or flame as a leak detector. Use non-ionic soap suds or a proper liquid leak detector.
e. A lighted cutting torch must be handled with care to prevent the flame from coming in contact with the diver's dress or umbilical. A lighted torch should not be left unattended or in such a position that it is free to swing and possibly foul lines.
f. Lowering a lighted MAPP gas torch to a diver should be done only in shallower depths and in locations where it is absolutely certain that the flame can be kept clear of all hoses, lines and the diver's umbilical and dress. A lighted torch should never be lowered until the diver is ready and watching for it.
D-11.2 Additional Safety Precautions. The following additional precautions must be observed:.
a. Use only authorized equipment which is in proper working order. All equipment shall be operated and cared for in accordance with manufacturers operating and maintenance instructions.
b. A diving tender shall be assigned to the care and control of the gas, with unhindered, quick access to the valves in case of an emergency.
c. Frequently inspect for evidence of leaks in the hoses, couplings, valve stems or other parts of the system while equipment is in use, especially in confined spaces. Failure to do this can result in the accumulation of an explosive mixture. This is a serious explosive hazard.
d. Metal tools (even the "sparkless" type) shall be used with caution to avoid making a spark. Such a spark could cause an explosion if the proper mixture is present.
Was this article helpful?