Safety talk about compressed gases 02/05/2013 Source: EHS (512) Airgas (866) (training = OH204) 1

Gases classification, hazards Argon, nitrogen Helium, carbon dioxide Hydrogen, Methylamine, Carbon monoxide, Acetylene, ammonia… Carbon monoxide, Phosgene, HCl HCl, phosgene Oxygen, nitrogen oxides (NO, NO 2 ), chlorine Dangerously Reactive Gases like acetylene are very easy to ignite: Slight temperature, pressure increases, static electricity or mechanical shock => polymerization or decomposition reactions => Fire or explosion Oxygen: seems to be harmless but we must be very careful ( flash fires => severe burns) If you are not sure: take a look to the Material Safety Data Sheet (MSDS) The only safe means of determining product identity: cylinder labels (colors cannot be used) 2

Cylinder identification 1. Department of transportation, cylinder type of material of construction (3AA), working Pressure in psi (2,265) 2. Serial number 3. Date of manufacture 4. Original owner of the cylinder 5. Retest markings (month-facility-year-plus ratings-star stamp, with = 10-year retest instead of 5 and = qualifies for 10% overfill 6. Bar code label (to track cylinders) 7. manufacturer’s inspection marking 8. Cylinder tare 3

Under high pressure and heavy cylinders Cylinder properties 4

Storage hazards uncontrolled rockets or pinwheels Secured by a strap or a chain (upright position) Arrangement of cylinders will increase the stability of secured cylinders (at least three points of contact) Temperature < 130 degrees F Proper ventilation (do not store in confined spaces without ventilation) Safety caps Incompatible gases (oxidizers and flammable gases) stored separately ( a minimum of 20 feet between cylinders) Fire and/or explosion 5

Transport hazards uncontrolled rockets or pinwheels Fire and/or explosion Secured by a strap or a chain to the cart Use the cap (remove regulators and pigtails) Pay attention to the pathway Proper clothing and closed-toed shoes 6

Utilization Hazardous gases should be used in areas with proper ventilation (gas cabinets and chemical fume hoods) Check the compatibility of the cylinder gas regulator: rated for Full cylinder pressure (regulators must be used!!) Valves, pigtails, regulators all have the potential to leak 1.Loosen the connection 2.Check the seating surface 3.Realign the connections and tighten with a wrench (not too much) 4.If it still leaks, notify EHS and the gas supplier Do not use Teflon tape (contaminants into gas stream) or lubricants (particularly with oxidizing gases) Open valves (first cylinder valve) slowly standing to the side of the regulator When you finished: close valves (pressure gauges = 0psi) Highly toxic gas: contact EHS (special storage, training, monitoring may be required) 7