Compressed Gas Safety for Laboratories

1. Compressed Gas Safety for Laboratories Discussion topics: Potential hazards Safety considerations regarding: Selecting/ Receiving gases Handling cylinders Use & Storage Research Experiments & Systems Emergency procedures Stanford University Environmental Health & Safety Occupational Health & Safety Program, 725-3209, lsteng@stanford.edu Stanford Fire Marshal’s Office 723-0609, jleung@stanford.edu Conmpressedgas.Rev.9-2000.ppt IH Report#: 98-080 / SUFMO #02-00

2. Additional Training Will Be Required 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. • 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……

3. 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

4. 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.

5. Types of Gases • 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

6. Potential Hazards • High Pressure • Asphyxiation • Flammability • Explosion • Toxicity • Corrosion • Oxidation • Pyrophoric • Cryogenic

7. 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

8. Cylinder Story Cylinders come in different sizes, shapes and colors Remember the gas supplier must label the cylinder with the contents Check the label before you accept, move or use the cylinder.

9. 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

10. 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

11. 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

12. 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

13. 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 to understand the permitting and engineering control requirements.

14. 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

15. 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

16. 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.eud • Stanford Fire Marshal’s Office- EH&S • Joseph Leung, 723-0609, jleung@Stanford.EDU