Introduction
Compressed gas cylinders can be extremely hazardous when misused or abused.
Compressed gas cylinders can present a variety of hazards due to their pressure and/or content.
Depending on the particular gas, there is a potential for simultaneous exposure to both mechanical and chemical hazards. Gases used maybe:
• Flammable or combustible
• Explosive
• Corrosive
• Poisonous
• Inert
• or a combination of hazards
Without proper use and care compressed gas cylinders can explode killing workers and destroying equipment. Cylinders can also become flying projectiles when cylinder valves are damaged or broken off. Regulators can become bullets that tear through workers if safety precautions are not taken.
Careful procedures are necessary for handling the various compressed gases, cylinders, regulators or valves used to control gas flow, and the piping used to confine gases during flow.
Handling and Use
1. Before cylinders are first used the following precautions should be taken:
• Make sure the cylinder is equipped with the correct regulator.
• Inspect the regulator and cylinder valves for grease, oil, dirt, and solvent. Never use
grease or oil to lubricate regulators or cylinder valves because they can cause an
explosion.
• The cylinder should be placed so that the valve handle at the top is easily accessible.
• When using toxic or irritating gas, the valve should only be opened while the cylinder
is in a working fume hood.
• Only use wrenches or tools that are provided by the cylinder supplier to open or close
a valve. Pliers should never be used to open a cylinder valve. Some regulators
require washers; this should be checked before the regulator is fitted.
• Refer to MSDS for the gas being used for information regarding use and toxicity.
• Fire extinguishing equipment should be readily available when combustible materials
can be exposed to welding or cutting operations using compressed cylinder gases.
2. Cylinder Storage
Gas cylinders must be secured at all times to prevent
tipping.
Use appropriate material, such as chain, plastic
coated wire cable, commercial straps, etc., to secure
cylinders.
Gas cylinders can not be stored in public hallways or other unprotected areas.
Cylinders must be segregated in hazard classes while in storage. Oxidizers (oxygen)
must be separated from flammable gases, and empty cylinders must be isolated from
filled cylinders.
The proper storage for oxygen cylinders requires that a minimum of 20 feet is
maintained between flammable gas cylinders and oxygen cylinders or the storage area
be separated, at a minimum, by a firewall five (5) feet high with a fire rating of 30
minutes.5
Store out of direct sunlight and away from sources of heat and ignition; temperatures
must not exceed 125 F.
Acetylene cylinders must never be stored on their sides.
Always place valve protectors on gas cylinders when the cylinders are not connected
for use.
Cylinders must be protected from damage. Do not store cylinders near elevators or
gangways, or in locations where heavy-moving objects may strike or fall on them.
Cylinders must be stored where they are protected from the ground to prevent rusting.
Cylinders should be protected against tampering by unauthorized individuals.
Storage areas must be well-ventilated, cool, dry, and free from corrosive materials.
3. Moving Cylinders
• Never drag, slide or roll a cylinder; use a
cylinder cart or basket.
• Always have the protective cap covering the
valve when transporting the cylinder.
• Never transport the cylinder with the
regulator in place.
• Make sure the cylinder is secured to the cart
before moving it.
• Do not drop cylinders or strike them against each other or against other surfaces
violently.
• Do not use the valve cover to lift cylinders; they could be damaged and become
unattached. If the cylinder is dropped on a hard surface it can cause an explosion.
4. Use and Operation
Only properly trained personal should handle compressed gas cylinders.
Back off the pressure adjusting screw of the regulator to release spring force before
opening the cylinder valve.6
Open the valve slowly and only with the proper regulator in place. Stand with the
cylinder between yourself and the regulator (cylinder valve outlet facing away) when
opening the cylinder valve.
Acetylene or other flammable gas cylinder valves should not be opened more than ½
turns of the spindle, and preferably no more than ¾ of a turn. This reduces the risk of
explosion and allows for the cylinder valve to be closed quickly to cut off the gas
flow.
Never heat a cylinder to raise the pressure of the gas (this can defeat the safety
mechanisms built in by the supplier).
Keep the cylinder clear of all electrical circuits, flame, and sparks.
Never leave the valve open when equipment is not in use, even when empty; air and
moisture may diffuse through an open valve, causing contamination and corrosion
within the cylinder.
Do not refill a cylinder, mixing of residual gases in a confined area may cause a
dangerous reaction.
Never use copper fittings or tubing on acetylene tanks – an explosion may result.
Never use compressed gas to dust off clothing, this could cause injury to the eyes or
body and create a fire hazard. Clothing can become saturated and burst into flames if
touched off by an ignition source such as a spark or cigarette.
Never leave pressure in a regulator when it is not in use.
Valve protection caps should remain in place until ready to withdraw gas, or connect
to a manifold.
Cylinder discharge lines should be equipped with approved check valves to prevent
inadvertent contamination of cylinders connected to a closed system.
Do not force connections that do not fit.
Close the cylinder valve and release all pressure before removing the regulator from
the cylinder.
Do not smoke when oxygen or fuel gases are present. Smoking can cause a fire or
explosion.7
Do not use acetylene at operating pressures above 15 psig.
Purge fuel and oxygen hoses individually before lighting up a torch tip.
Follow the equipment manufacturer’s operating instructions at all times.
If an outlet valve becomes clogged with ice, thaw it with warm water (if the gas is not
water reactive), applied only to the valve.
Use the cylinder valve for turning gas off, not the regulator.
Workers should wear safety glasses and face shields when handling and using
compressed gases, especially when connecting and disconnecting regulators and
lines.
OXYGEN IS NOT COMPRESSED AIR, IT IS OXYGEN
Never use oxygen as a substitute as a “compressed air” to run pneumatic tools, in oil
heating burners, to start internal combustion engines, to blow out pipelines, or to
create pressure for ventilation.
Oxygen cylinder valves should be opened all of the way during use.
5. Cylinder Leaks
• If the cylinder contains a flammable, inert, or oxidizing gas, remove it to an isolated
area, away from possible ignition sources. Allow it to remain isolated until the gas
has discharged, making certain that appropriate warnings have been posted.
• If the gas is a corrosive, remove cylinder to an isolated, well-ventilated area. The
stream of leaking gas should be directed into an appropriate neutralizing material.
• For toxic material, the cylinder should be removed to an isolated, well-ventilated
area, but only if this is possible while maintaining personal safety. It may be necessary to evacuate the facility.
• If the leak is at the junction of the cylinder valve and cylinder, do not try to repair it. Contact the supplier and ask for response instructions.
• Never use a flame to detect a gas leak. Use soapy water.
6. After the cylinder is no longer needed, the following steps should be taken:
Do not completely empty the cylinder; always leave some residual pressure.
If the cylinder is empty, replace the cap and remove it to the empty cylinder storage area.
Label all empty cylinders with tags so that everyone will know their status. Empty cylinders can be marked with “MT and date” with chalk. Handle empty cylinders as carefully as full ones; residual pressure can be dangerous.
Never refill a cylinder. This requires specialized equipment and techniques.
Never mix gases in a cylinder. The next person who draws from it may unknowingly cause an explosion.
7. Piping for compressed air
• Polyvinyl chloride (PVC) plastic pipes can not be used for transporting compressed
gases aboveground unless they are completely enclosed in a conduit or casing of sufficient strength to provide protection from external damage and deterioration. The heat generated from compressed air can weaken the PVC pipe and create an explosion hazard. When PVC piping explodes, plastic shrapnel pieces can be thrown in all direction and injure workers or damage equipment.
• Copper piping shall not be used for acetylene.
• Do not use cast iron pipe for chlorine.
• Distribution lines and their outlets need to be clearly labeled.
• Inspect piping systems on a regular basis.
• Pay attention to fittings as well as possible cracks that may have developed.
8. Hoses and Connections
Examine hoses regularly for leaks, set up an inspection schedule.
Do not use unnecessarily long hoses.
Keep hoses free from kinks and away from high traffic areas.
Repair leaks promptly and properly.
Store hoses in a cool place, and protect them from hot objects, and sparks.
Do not use a single hose having more than one gas passage.
II. Engineering Controls
Listed below are some engineering controls that can be used in some cases to control the
risk of compressed gas use.
1. Emergency Shutoff Switch – can be used at a remote location to cause pneumatic
valves to shut, stopping gas flow. Switches should be non-electric so that arcs or sparks
are not created around flammable gases.
2. Gas Cabinets – hazardous gas cylinders should be housed in a gas cylinder cabinet.
These cabinets can be equipped with sprinkler protection and ventilation.
3. Flow Restrictors – can be used to limit hazardous gas flow to just over maximum flow
needed, must be installed immediately downstream of each hazardous gas cylinder.
4. Emergency Eyewash – must be present in areas were corrosive materials or gas is
used.
General Handling
Safety glasses, gloves and safety shoes should be worn at all times when handling cylinders. Appropriate firefighting, personnel safety and first aid equipment should be available in case of emergencies.
Transporting Cylinders
Always move cylinders by a hand truck or cart designed for this purpose. During transportation, cylinders should be properly secured to prevent them from falling, dropping or striking each other. Never use a cylinder cart without a chain. Do not move a cylinder with a regulator connected to it. Never transport a gas cylinder without its valve protection cap firmly in place. Keep both hands on the cylinder cart during transport. Remember a cylinder cart or hand truck is not a suitable place for storage of a cylinder. If a cylinder is equipped with our exclusive ergonomic cap, do not remove it. Never lift a cylinder by its cylinder cap. The threads are affixed to the cylinder body; lifting it by the cap will cause the cap to detach from the body.
Compressed Gas Cylinder Usage
General Usage
Appropriate firefighting, personnel safety and first aid equipment should be available in case of emergencies.
Labeling
If a cylinder’s contents are not clearly identified by the proper cylinder labels, do NOT accept for use. Observe all warnings and precautions indicated on the cylinder label.
Securing Cylinders
Before Use When a cylinder is in use, it must be secured with a fastener. Floor or wall brackets are ideal for stationary use. Portable bench brackets are recommended for when cylinders must be moved. Smaller stands are available as well for lecture bottle use. Your Air Liquide representative can assist you in determining which type of cylinder fastener best meets your needs.
Initiating Service of Cylinder
Secure the cylinder before removing the valve protection cap. Remove the protective cap and inspect the cylinder valve for damaged threads, dirt, oil or grease. Remove any dust or dirt with a clean cloth. If oil or grease is present on the valve of a cylinder that contains oxygen or another oxidant, do NOT attempt to use it. Such substances in contact with an oxidant are explosive.
Valve Outlet Connections and Fittings
Be sure fittings and connection threads meet properly – never force. Dedicate your regulator to a single valve connection even if it is designed for different gases. NEVER cross thread or use adapters between nonmating equipment and cylinders. Most valve outlet connections are designed with metal-to-metal seals; use washers only if indicated. Do not use PTFE tape on the valve threads to prevent leaking, it may become powdered and get caught on the regulator poppet causing full pressure downstream. Never use pipe dope on pipe threads. Also, never turn the threads the wrong way. This may produce brass particles that might get caught in the regulator’s poppet.
Terminating Service of Cylinder
Always disconnect equipment from the cylinder when not in use and return the valve protection cap to the cylinder.
Follow requirements for storing Compressed Gases cylinders:
• Select a cool, dry, and well-ventilated area.
o Cool areas minimize pressure increases that can result from heat or direct sunlight.
o Dryness deters rust and corrosion.
o Ventilation is essential in case of leaks.
o Never store compressed gas cylinders (with the exception of compressed air) in environmental rooms (i.e., refrigerated cold rooms or warm rooms). These rooms are not well ventilated and could pose a serious safety concern should a cylinder fail.
• Do not store cylinders next to doors or in corridors where they could possibly obstruct emergency exit from the building.
• Separate oxidizers or other non-compatibles (e.g., oxygen) from flammables by at least 20 feet, or by a non-combustible wall.
• Properly label the cylinders and the storage area.
• Arrange storage facilities to permit inventory rotation, using cylinders in order as received from the supplier.
• Store full and empty cylinders separately to avoid confusion. Serious suck-back can occur when an empty cylinder is attached to a pressurized system.
• Designate an area to store empty cylinders for return to the supplier. An area on or adjacent to your building's loading dock is suitable.
Restrain CG cylinders
Restrain your cylinders
Compressed gas cylinders must be secured at all times, whether empty or full.
How to effectively restrain cylinders:
• Store cylinders upright and secure them to a substantial, fixed surface with upper and lowerrestraints made of non-combustible material, preferably chain.
• Position the upper restraint no less than 1 foot from the shoulder of the cylinder. Position thelower restraint no less than 1 foot from the floor.
• C-clamps or bench mounting brackets are not allowed!
• Multiple cylinder restraint - Limit 3 cylinders to each double-chain restraint system.
• Cap cylinders when not in use.
• Cap cylinders when not in use.
Operational requirements
Read the Safety Data Sheet and label information before starting work with a new material.
Follow these operational requirements:
• Label both the cylinder and gas line with the name of the gas. Do not depend on color codes.
• Work in a well-ventilated area when using compressed gases.
• Use the correct regulator. Ensure each gas in use has its own dedicated regulator. Never use adapters.
• Never permit a flame or spark to come in contact with any part of a compressed gas cylinder.
o Install flashback protectors on cylinders of flammable gases, such as oxy-acetylene torch units.
• Use a trap or suitable check valve when discharging gas into a liquid to prevent liquid from getting back into the cylinder or regulator.
In case of leaks
In case of cylinder leaks that cannot be stopped by tightening the valve gland or packing nut, do the following:
Transporting gas cylinders
Follow these best practices for transporting CG cylinders:
• Leave the valve protection cap on until the cylinder is secured against a wall or bench or placed in a cylinder stand, and is ready for use.
• Use a hand truck or other suitable device to transport cylinders, even for short distances. Secure the cylinder to the hand truck with a chain or strap.
o Do not roll, drag, or slide containers.
o Do not lift cylinders by cylinder caps.
• Before returning empty cylinders to the supplier:
o Close the valve. Leave some positive pressure in the cylinder.
o Replace original valve outlets and protective caps shipped with the cylinder.
o Mark or label the cylinder "empty" and store it in a designated area for the supplier.
• Important: Move unattended cylinders to a secure location as soon as possible.
Flammable, oxidizing, and corrosive gases
In addition to standard storage and operational requirements listed above, employ special precautions for cylinders containing flammable, oxidizing, or corrosive gases (empty or full).
Flammable gases
• Storage:
o Separate from cylinders containing oxidizing gases by a minimum distance of 20 feet or by a noncombustible partition extending not less than 18 inches above and to the sides of the stored material.
o When approved gas storage cabinets are used, the cabinets must be equipped with fire sprinklers.
o Never store flammable gas near ignition or heat sources, or unprotected electrical connections.
o Keep quantities to a minimum.
• Operations:
o Use flow restrictors to prevent a sudden large unexpected release.
o Detection systems may be required.
• Operations:
o Diligently clean regulators and tubing used with oxidizing gases to remove oil and other reducing agents.
Compressed Gases Self-Inspection Checklist
Guidelines
This checklist covers regulations issued by the U.S. Department of Labor, OSHA under the General Industry standard 29 CFR 1910.101. It applies to the handling, storage, and use of compressed gases in cylinders or portable tanks. The regulations cited apply only to private employers and their employees, unless adopted by a state agency and applied to other groups such as public employees.
The OSHA standard adopts by reference the Compressed Gas Association's (CGA) Pamphlets C-6-1986, C-8-1962, and P-1-1965. The following questions relate to the more common precautions to be taken in school environments. The checklist, however, is not all inclusive. The Compressed Gas Association has updated the three pamphlets cited by OSHA as C-6-1993, C-8-1997, and P-1-1999.
Hi,
ReplyDeleteThanks for sharing your great checklist of tips, i really appreciate your research.
We are leading gas suppliers company engaged in LP Gas, Gas Cylinder, Gas Bottle, LP Gas.