Compressed Gas Safety for Laboratories

Stanford UniversityEnvironmental Health & Safety

Occupational Health & Safety Program, 725-3209, lsteng@stanford.edu

Stanford Fire Marshal’s Office723-0609, jleung@stanford.edu

Conmpressedgas.Rev.9-2000.pptIH Report#: 98-080 / SUFMO #02-00

Discussion topics: Potential hazards Safety considerations regarding:

Selecting/ Receiving gases

Handling cylinders

Use & Storage Research Experiments & Systems Emergency procedures

Additional Training Will Be Required

If you don’t understand ask questions! If you forget ask questions! If it doesn’t seem right ask questions!

We would rather answer questions than deal with a accident……

This training provides information about safe handling, storage and general hazards of compressed gases. It does not provide specific detailed training necessary to safely install or use compressed gases. Prior to actual use of any compressed gases your supervisor will need to provide operation specific training in this area.

Regulations for Compressed Gas Use & Storage

Compressed gas use & storage are regulated by different organizations.• California Fire Code• Occupational Safety & Health Administration

(CalOSHA)• Santa Clara County Environmental Health

Department

Characteristics of Gases

Gases are much lighter than liquids & solids.

The molecules of a gas are always in motion.

Escaped gases will eventually distribute themselves throughout the air in a room or other confined space.

Some gases have odors, some do not.

Most gases are invisible, some can be seen.

All gases have some property that can be hazardous to you.

Non-liquefied Compressed Gases – Nitrogen, Argon, Helium, Oxygen, Hydrogen

Liquefied Compressed Gases-Chlorine, Hydrogen chloride, Carbon Dioxide, Nitrous Oxide, Dichlorosilane, Hydrogen Bromide

Compressed Gases in a Solution-Acetylene

Cryogenic Liquefied Gases-Nitrogen, Argon, Helium, Oxygen, Hydrogen

Types of Gases

Potential Hazards

High Pressure Asphyxiation Flammability Explosion Toxicity Corrosion Oxidation Pyrophoric Cryogenic

Purchasing/ Receiving Gases

REDUCE YOUR RISKS! Select the lowest concentration of hazardous gas

that will allow you to perform your experiment. Purchase the smallest quantities to satisfy your

research needs. Select only gases that are delivered in returnable

containers When receiving gas cylinders:

• Check for leaks• Visually inspect for damage• Ensure valve cover and shipping cap are

properly in place.• Check that cylinder is properly labeled

Cylinder Story

Cylinders come in different sizes, shapes and colors

Remember the gas supplier must label the cylinder with the contentsCheck the label before you accept, move or use the cylinder.

Safe Handling of Gas Cylinders

Before handling, make sure that valve cap is secured

Transport gas cylinders using only a suitable cart Always take the safest most direct route when

transporting gas cylinders

Never leave un-restrained cylinders un-attended

Safe Storage of Compressed Gas Cylinders

Only store cylinders in authorized locations. Separation of incompatibles (check SU storage group

information) Restricted access to compressed gas cylinder storage. Store away from main building access/ egress points

Safe Storage of Compressed Gases

Attach valve cap when a gas cylinder is not in service Cylinders must be stored upright Metal restraints at 1/3 AND 2/3 height of cylinder Max of 2 gas cylinders per set of chains

Cylinder bench clamps

are NOT allowed

Safe Use of Compressed Gases

DO NOT tamper with the stem and cylinder valves NEVER use damaged regulators, connectors, piping, etc. For cylinders in use, cylinder valves must have hand wheel

attached Close cylinder valve whenever:

• work is finished• cylinder is empty

Label empty cylinders Ensure safe & proper exhaust for purging & pressure relief for

toxic, flammable, or corrosive gases

Additional Precautions

Some gases require special permits and controls for use. These are toxic, corrosive, flammable and pyrophoric gases. Check with SU EH&S during the design of the experiment in order tounderstand the permitting and engineering control requirements.

Research Experiments and Systems

Label all gas lines Remember to check safety devices (check valves, flow

restrictors, pressure gauges, regulators) Select proper construction materials Leak test system before start-up & at cylinder changes Check for proper exhaust ventilation for the lab and

apparatus prior to opening gas cylinders

Emergency Procedures

Standard Operating Procedures (SOP)• Bottom line….Not only are they a good idea,

they are required!

BE PREPARED!• Know your emergency procedures• Know your emergency contacts• Know what to do “if” the unexpected happens

For More Information EH&S Compressed Gas training Guide to Safe Handling of Compressed

Gases, Matheson Handbook of Compressed Gases,

Compressed Gas Association Gas Data Book, Matheson

Occupational Health & Safety Program- EH&S

•Ling Sue Teng, 725-3209, lsteng@stanford.eudStanford Fire Marshal’s Office- EH&S

•Joseph Leung, 723-0609, jleung@Stanford.EDU