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Compressed Gas Cylinder Safety
INTRODUCTION
Compressed Gas Cylinders usually contain gases stored at very high pressure (usually around 2200 psi) and are connected with a hose and a regulator when in use.
Many industrial and laboratory operations require the use of compressed gases for a variety of different operations.
INTRODUCTION
Compressed gases present a unique hazard. Depending on the particular gas, there is a potential for simultaneous exposure to both mechanical and chemical hazards. Gases may be:
Flammable or combustible (acetylene, butane, ethylene, hydrogen)
Explosive
Corrosive (Ammonia, Chlorine)
Poisonous (Hydrogen Sulfide, Carbon Monoxide)
Inert (argon, helium, neon and nitrogen)
or a combination of hazards
Physical Hazards and Health Effects
Asphyxiation: can be caused by high concentrations of even "harmless" gases such as nitrogen.
Large amount of potential energy resulting from compression of the gas makes the cylinder a potential rocket or fragmentation bomb.
The concentration, the length of exposure, and the route of exposure for all gases are different. Always refer MSDS before handling compressed gases.
Mechanical Parts of a Gas Cylinder
All compressed gases, cylinders containing them, the regulators or valves used to control gas flow, and the piping used to confine gases during flow should be carefully handled.
Identification & Labeling
Identify clearly the contents of a cylinder before using.
Read the stenciled or stamped information on the cylinder or on a label provided by the manufacturer/supplier.
Never rely on the color of the cylinder for content identification. It varies with suppliers and may be difficult to interpret for personnel with color blindness.
All cylinders have a tag representing its current state (full or empty) and contents.
Identification and Labeling
Do not use a cylinder if you cannot read its contents.
Do not accept a cylinder from the supplier if you cannot read its contents.
Do not rely on color coding.
If labeling is not clear or attached tag is defaced, mark the cylinder as "contents unknown" and return it to the manufacturer.
Do not identify cylinders with labels on caps because cylinder caps are interchangeable.
Storage, Handling and Use
Gas cylinders must be secured at all times to prevent tipping. Cylinders may be attached:
to a bench top
individually to the wall
placed in a holding cage
have a non-tip base attached.
Storage, Handling & Use
Ensure that the cylinders are secured by using Chains or sturdy straps around them.
Always keep the chains and straps tight so that cylinders do not fall due to sudden hit.
Storage, Handling & Use
Store cylinders according to compatibility:
Refer to individual MSDS for each gas and ensure compatibility with other stored gases.
For incompatible gases, ensure adequate segregation.
Always store Flammable gases away from Oxidizers (Oxygen gas).
Consult RMS for segregation requirements.
Significance of Inert Gas Law
Inert Gas Law: P.V.=n.R.T
From above, Temperature is directly proportional to Pressure and vice versa.
So, never store gas cylinders under sunlight or near heat sources. Increase in temperature may increase gas pressure and resulting in increase in volume which causes explosions.
Transportation Of Cylinders
Compressed Gas Cylinders should not be subjected to rough handling or abuse during transportation or shipping. Mishandling can seriously damage the cylinder rendering it unfit for further use.
Ensure that the cover cap should is screwed hand tight and remains on the cylinder until ready for use.
Cylinders should be strapped to a adequately designed wheel cart to ensure stability.
Cylinders should never be rolled or dragged.
Only one cylinder should be handled at a time.
Leaks, Breaks and Reporting
If you suspect a leak from the gas cylinder, use the following procedures:
1. for a flammable gas, a flammable gas detector, a soapy water solution or a 50% glycerin-water solution may be used;
2. for toxic or corrosive gases, first test the system with an inert gas before introduction of the hazardous material.
If a leaking cylinder is discovered, move it to a safe place (if it is safe to do so) and inform the Risk Management & Safety. You should also call the vendor as soon as possible.
Cylinder Accessories
Some of the accessories which are required for safe usage of compressed gas cylinders are:
Hand Wheel or Stem Valve: For cylinders equipped with hand wheel or stem valve, the valve key shall remain on the cylinder stem until the cylinder is taken out of service.
Wrenches and other tools: Only tools provided by the supplier shall be used to open or close a valve.
At no time should pliers be used to open a cylinder valve.
Storing Flammable Gases
Flammable Gas Cylinders (hydrogen or acetylene)
should never be stored:
in close proximity to open flames,
in areas where electrical sparks are generated,
or where other sources of ignition may be present.
Storing Flammable Gases
Always take the following precautions while storing flammable gases:
Never store oxygen cylinders, full or empty in the same vicinity as flammable gases. Maintain at least 20 ft distance.
Never use an open flame to detect leaks of flammable gases.
Always store flammable gas cylinders in a well-ventilated area.
Handling Empty Cylinders
When rendering cylinders out of service, ensure the following:
Close all valves, bleed the system, and remove the regulator.
Replace valve cap , mark cylinder as “empty” and contact the supplier for pick up.
Store empty cylinders in separate areas.