This standard operating procedure (SOP) is intended to provide general guidance on how to safely work with compressed gases. This general use SOP only addresses safety issues specific to compressed gases. In some instances, several general use SOPs may be applicable for a specific chemical (i.e., for flammable gases, both this general use SOP and the general use SOP for flammables would apply). If you have questions concerning the applicability of any item listed in this procedure contact the Principal Investigator/Laboratory Supervisor of your laboratory or Environmental Health and Safety (x3-0448).

Compressed gases have inherent pressure hazards and can also create health hazardous and/ or flammable atmospheres. Common hazard characteristics of gases include flammability, toxicity, and corrosivity. A few gases (i.e., silane, diborane, phosphine) are considered pyrophoric (will ignite spontaneously in air).

One additional hazard property common to all compressed gases is the substantial volume expansion when released to air. Gas release in an inadequately ventilated room can create an oxygen-deficient environment.

• Check connections and hoses regularly for leaks using a specific monitoring instrument or soapy water (or equivalent).
• When using highly flammable or toxic gas, check the delivery system using an inert gas prior to introducing the hazardous gas.
• When using compressed acetylene: (i) do not exceed a working pressure of 15 psig, and (ii) do not use vessels, piping, or other materials that contain a significant amount of copper (usually considered to be more than 50% copper).
• Replace valve caps when cylinders are not in use or before moving.
• Remove damaged or defective cylinders from service (contact the cylinder vendor for assistance).

If the process does not permit gas use and/or storage in well-ventilated areas (i.e., lab ventilation having a minimum of 6 air changes per hour), contact Environmental Health and Safety at x3-0448 to determine necessity of an oxygen-deficiency monitor or other alarm devices.

At minimum, lab coats, safety glasses, and closed toed shoes should be worn when handling compressed gases. Depending on the hazard characteristics, additional protective equipment may be necessary.

Safe Handling:

• Compressed gas cylinders must be transported using hand-trucks or other appropriate means. NEVER TRANSPORT UNSECURED COMPRESSED GAS CYLINDERS!
• Cylinders should be transported upright whenever possible (always transport acetylene in an upright (vertical) position).
• Elevators can be a confined space – NEVER ride in an elevator with compressed gas cylinders. Have one person send the elevator and another person receive the elevator.

Safe Storage:

• Secure compressed gas cylinders (>26" tall) to an anchored rack using two metal chains (at 1/3 and 2/3 cylinder height).
• No more than two cylinders may be secured with one pair of chains.
• Segregate and clearly mark full and empty ("MT") cylinders.
• Store compressed gas cylinders away from heat sources, and flammable and highly combustible materials (such as oil and greases).
• Segregate according to hazard class and chemical compatibility. Ensure to separate flammable and oxidizing gases.
• Store flammable gases away from flammable solvents, combustible material, ignition sources (including unprotected electrical connections), and oxygen gas cylinders and liquid oxygen (at least 20 feet if possible).

Additionally, follow all substance-specific storage guidance provided in MSDS documentation.

Laboratory personnel who work with hazardous chemicals are to be provided the opportunity to receive medical attention/consultation when:

• A spill, leak, explosion or other occurrence results in a hazardous exposure (potential overexposure).
• Symptoms or signs of exposure to a hazardous chemical develop.

Coordinate with vendor for return of cylinders.

• General Safety & Emergency Preparedness (EHS-4200)
• Chemical Safety for Laboratories (EHS-1900)
• Compressed Gas Safety (EHS-2200)
• Laboratory-specific training

Consult with PI regarding need for prior approval. Laboratory personnel shall seek and the PI must provide prior approval of any chemical usage involving the following list of restricted chemicals.

Not applicable

For compressed gases that are also considered particularly hazardous chemicals, a designated area shall be established per the other applicable SOP(s).