Jewelers work with compressed gases of all kinds, in torch
systems, kilns, casting machines, abrasive blasters, laser welding machines
needing argon and more. Many of these gases are flammable and an explosion
hazard, acetylene, propane and hydrogen are examples. Oxygen is often
used with these gases. Oxygen is a potent fire risk if it comes in contact
with oils, greases or flammable materials, even fingerprint grease left
in a fitting has caused a fire before.
Some gas handling guidelines:
- Always read the manufacturers operating instructions slowly and carefully
three times and then review them every six months. If you don't have
them get a set from your gas distributor, either specific for your equipment
or general ones. Always follow those instructions, you can be hurt if
you do something different with the equipment. Also make sure you are
properly instructed in their use by a knowledgeable user or three.
- Keep a maintenance log for the gas equipment and inspect it regularly.
- Check with your fire department about proper installation and legal
issues of having your gas equipment. Do the same with your insurer (this
is a reason why some jewelers use 'water torches which avoid the problem
of storing gas on the premises because the torch makes hydrogen and
oxygen for fuel as you need it).
- Use good housekeeping practices in the work area. Keep things tidy
and cleaned up. Only have the necessary tools out on work surfaces.
Prepare your work area. Do not have flammable or combustible materials
near the work area.
- Always check labels to see the right gas is being used. Oxygen regulators
and hoses should be marked with 'Use No Oil'.
- Never fill one cylinder from another or refill a cylinder yourself.
- Only use equipment and fittings for the gases they were designed
for, using acetylene for instance with copper pipe can cause copper
acetylide to form which can cause an explosion.
- Always handle cylinders carefully. Do not drop them, bump them, or
use them as rollers to move heavy objects (no kidding-that has been
an accident cause) or as supports.
- Have any repairs done by the qualified people, do not modify or repair
cylinders, valves, regulators yourself unless you too are properly trained
to do that. If you are changing service companies or regulators from
one company to another's equipment be very careful that contamination
does not result which could result in fire or explosion.
- Do not handle cylinders with greasy hands or gloves.
- Never position cylinders near any electrical equipment or process.
- Do not use torch equipment near flammables of combustibles.
- Wear fire resistant clothing - this is really important. Tie your
hair back, wear no jewelry etc. - most standard rules for using tools
count here as well. Foot protection is necessary with much torch work.
- Always keep cylinders chained up to a permanent fixture to prevent
them falling, particularly important with compressed gases like large
acetylene tanks, nitrogen and oxygen cylinders.
- Keep cylinders and valves clean at all times to avoid leaks. When
attaching the regulator blow out any dirt in the opening by opening
and closing the valve for a brief instant (use eye protection). Inspect
the filter in the inlet nipple of an oxygen regulator to see that it
is in position and clean. If it is missing take it to your repair shop
to be re-fitted.
- Oxygen valves should be washed out with a grease cutting solution
that will not react with oxygen. Hot water with caustic soda or trisodium
phosphate are effective for this. Rinse well afterwards. Don't use an
oxygen tank near grease or oil, or handle any part of it, tank, valve,
regulator etc. with greasy hands or with gloves.
- When installing new hose blow it out at 5 psi first before attaching
equipment to it.
- Never crack a tank valve near hot work, sparks or any other possible
- Always shut cylinder valves during work breaks, when leaving the
shop and when the cylinder is empty. Do not leave pressure on the regulator
when it is not in use.
- Never put a torch down with the gas flow on. If you use a pilot light
then an appropriate rack and holder away from combustible materials
(including your arm and your co-workers) is necessary.
- Open valves slowly and carefully. Do not use too much force when
closing them. Never use a hammer or a wrench to open a cylinder valve.
- If a handwheel controls the valve on your tank do not use a hammer,
wrench or lever on it.
- Never lubricate any valve or fitting or use white, red lead jointing
compound, oil or grease. Remember hand soap is made with fat.
- Regularly test for valve and fitting leaks using soapy water or a
commercial window cleaning solution. Dip your hose in a bucket of water
with the gas pressure on to check for hose leaks. Test after changing
tanks and other times as well. Some people recommend testing for leaks
every time you use the system. Never use a flame to test for leaking
gases. While this seems obvious the number of warnings around on this
issue say something about previous accidents.
- Never use a torch system that is leaking. If it leaks around the
stem of a small acetylene tank the packing nut can often be tightened
to stop the leak.
- Do not use a full or partially full lighter as a striker to light
a torch with, either use a proper flint striker or use an empty lighter
you have drilled into to release any trace of lighter fluid. It is not
wise to keep disposable lighters near a torch system unless they are
completely emptied and aired out.
- An automatic pressure regulator should be fitted to all oxygen and
acetylene cylinders - needle valves in the torch tip are considered
inadequate. Ask your supplier about back flow check valves for your
equipment - you should have them.
- Check hoses frequently for signs of hardening, fraying, cracking
or perishing. Always use a top quality hose. The longer the hose is
the more likely it is to leak. Hose connections have to be securely
clamped so they will withstand twice the maximum pressure they are exposed
to when in use.
- Use red hoses for acetylene and green for oxygen.
- Never force fit mismatched connections - they are often different
on purpose for different gas systems . Do not force matched connections
either for that matter.
- Wear proper protective equipment when using torch equipment.
- Never turn an acetylene valve on more than 1/4-3/4 of a turn or place
objects upon it which could interfere with an emergency shut-off attempt.
Never open it more than 1 and a half turns. Always open cylinder valves
slowly. Open fully only after contents gauge stops moving. Never stand
in front or behind a regulator when turning it on in case it blows outwards.
- Acetylene pressure should not be over 15 psi as fire and explosion
can result. Use recommended pressure settings, improper settings are
wasteful and can be dangerous. If pressures build up high in the regulator
by itself then it needs to be repaired.
- If a tank wrench is needed then leave it in place while using the
- Never deliberately start fires or participate in horseplay while
using a torch system. Never, for instance, discharge a flow of gas pointing
- To avoid pressure unbalance and contamination of the cylinder do
not allow cylinders to become completely empty, especially oxygen cylinders.
25-50 psig is the point at which you should disengage the cylinder.
Check for adequate gas supplies before starting work.
- Be especially careful with hydrogen gas, ask your supplier for full
safety regulations. In some places the fire department needs to know
you have it on the premises.
- Never solder, braze or heat a container that has contained any flammable
liquids or vapors unless all traces of the flammable material have been
- Make sure that store rooms are well ventilated and have no heat sources
(radiators, furnaces etc.) that can warm the cylinders and raise pressures.
That goes as well for having the sun fall strongly onto them.
- Electric switches and light sources should either be fire proof or
placed outside the room. Store rooms should be fire proof and have easy
access to get the cylinders out in an emergency.
- No smoking, open flames, or grinding sparks near where compressed
gases are stored.
- Clearly mark empty cylinders 'M.T." and store separately from full
cylinders. Make sure all cylinders are properly marked as to their contents.
Labels should be hard to remove.
- Oxygen and acetylene should be stored apart, even in separate rooms.
OSHA says 20 feet away minimum, or with a fireproof barrier a minimum
five feet high between them. Keep oxygen away from any oil or grease,
flammable liquids. Never handle oxygen cylinders, tanks or valves with
oily fingers or gloves as fire and explosion can result. Do not place
an oxygen regulator or similar part onto a greasy surface thus contaminating
- Upright storage is usually easiest for a small shop. Store securely,
chained to a solid fixture to prevent them falling.
- Keep cylinder valves dirt, water, grease and corrosive free. If possible
always have the right valve cap finger tight on stored cylinders. Use
caps when transporting them. always take great care when moving gas
- Never use a damaged cylinder - report and return it to the supplier
- When you get the cylinders from the supplier (or delivered), check
them immediately for leaks, the packing nuts on 'B' tanks are often
not tight and besides the danger of leaking gas there is a real increase
in overhead costs if they leak.
- Never store acetylene or LP gas cylinders in a confined space like
the trunk of a car, closet or tool box.
- Flashback in the torch and hoses can cause a fire or explosion in the
hoses, valves or even cylinder.
Causes of flashback include:
- An accidentally damaged or blocked tip may stop the flow of gases
& cause a reverse flow from one line into the other, creating a dangerously
- Re-lighting after tip replacement without bleeding off all the gases
in the torch hoses and regulators, could result in an explosion causing
damage to the regulator or burned hoses.
- Pressure drop or an emptied tank may permit oxygen to enter the fuel
gas line, or fuel into the oxygen line. A reverse flow permitting mixing
of gases is always dangerous.
- Failure to bleed lines through the torch and neglecting to close
the regulator (i.e. back off pressure adjusting screw) when changing
to full tanks can cause the regulator to be filled with an explosive
mixture, which can be set off by heat of recompression as the fresh
tank of oxygen is connected and the valve opened.
- The flashback (reverse flow) check valves should be tested every
six months. Talk to your gas supplier about how to test your specific
version. The installation of proper flashback check valves can eliminate
almost all chance of a flashback accident.