Environmental Health & Safety

• Definition

  NFPA 55:3.3.49.1 Compressed Gas definition:

  A material, or mixture of materials, that (1) is a gas at 68°F (20°C) or less at an absolute pressure of 14.7 psi (101.3 kPa) and (2) has a boiling point of 68°F (20°C) or less at an absolute pressure of 14.7 psi (101.3 kPa) and that is liquefied, nonliquefied, or in solution, except those gases that have no other health or physical hazard properties are not considered to be compressed gases until the pressure in the packaging exceeds an absolute pressure of 40.6 psi (280 kPa) at 68°F (20°C).

• Requirement for Research

  Researchers working with compressed gases must have current Laboratory Hazard Assessment Tool (LHAT) and also develop and implement a Standard Operating Procedure (SOP).

• Hazard Classification

  Use and storage of compressed gases is strictly regulated according to hazard classification.

  • See the Toxic and Hazardous Gas Classifications Chart to identify the hazard class of a particular gas.

  Compressed gases are classified as class I, II, III, or IV in order of decreasing hazard.* Classes are based on the lethal concentration to 50% of test animals (rats) of each gas (LC50).

  UCR Compressed Gas Hazard Classifications
  Class I	LC50 (rat) ≤ 200 ppm
  Class II	201 ppm LC50 (rat) ≤ 2000 ppm
  Class III	2001 ppm LC50 (rat) ≤ 5000 ppm
  Class IV	LC50 (rat) > 5001 ppm

  * Note: The California Fire Code uses a different classification system. For more information, visit the UCR Fire Prevention website or call, (951) 827-2433.

• Storage & Use

  Storage and use requirements apply to all compressed gases.

  • Read Compressed Gas: Storage & Handling for detailed information.
• Additional Precautions

  Implement additional safety precautions for strong>particularly hazardous substances (classes I, II, and III). Requirements are relaxed for small quantities and short term usage.

  • See the Hazard Class Requirements Matrix for detailed information on requirements and exemptions.
• Purchasing
  • Follow the Chemical Hygiene Plan and Compressed Gas at all times.
  • Complete your Compressed Gas and/or gas specific Hazard Control Plan (HCP) in the LHAT prior to ordering your material.
  • There are fire code restrictions on the quantities of some gases regarding use and/or storage within research buildings. Examples include:
    • flammable (hydrogen, methane, acetylene)
    • oxidizer (oxygen, nitrous oxide)
    • highly toxic (arsine, phosphine, nitric oxide, nitrogen dioxide)
    • toxic (ammonia, hydrogen sulfide, carbon monoxide)
    • corrosive (hydrogen chloride, chlorine, hydrogen fluoride)
    • Unstable reactive (acetylene)
  • Order only what is needed for a reasonable amount of time.
  • Keep quantities to a minimum for all gases.
  • Reduce concentrations when possible.
  • View Compressed Gas Cylinders Overview for details on ordering, services, and rental fees to complete your purchase.
  • Order all in-stock and specialty gases through Marketplace.

  Important: To ensure safe use and storage of Class I, II, or III gases, visit

  the EH&S Chemical Hygiene website or call the Chemical Hygiene Officer, (951) 827-4254, before ordering material.

• Compressed Gas Safety Training

  All users or personnel in areas where compressed gas is used must receive general compressed gas safety training and task-specific training. Supervisors should assign training in the UC Learning Center and then follow up with hands-on site-and task-specific training. Training should cover safe handling and storage, regulator use, and emergency shut-down procedures. 

  Online compressed gas training is available for everyone in the UC Learning Center here: Compressed Gas Safety, course # RI-UCSKSS0019-ECO (30 min)

  You can also request in-person compressed gas training for groups by contacting EH&S Training at training@ehs.ucr.edu

  Additional training resources:

  In UC Learning Center: Compressed Gas Safety: Prework for Graduate Safety Orientation, course # RI-ESECO0130 (25:26 min.)

  This 2-video set was presented by Eugene Y. Ngai of Chemically Speaking LLC in May 2013 for researchers and Environment, Health & Safety staff. Key elements of a CG safety program and pre-planning for emergency response are covered.

  • Video 1: Overview of Compressed Gas Safety (59:18 min.)
  • Video 2:More on Compressed Gas Safety  (51:16 min.) with audience-driven topics

  

  All files courtesy of Chemically Speaking LLC

  • Compressed Gas Safety (PDF)
  • Oxygen System Safety (PDF)
  • Emergency Response:
    • Equipment (PDF)
    • Leak Detection (PDF)
    • Planning (PDF)
    • PPE and Decontamination (PDF)
  • Silane Gas:
    • Silane Safety Notes (PDF)
    • Silane Incident Notes (PDF)
• Compressed Gas Alternatives

  Gas cylinders are not always ideal in a lab setting for transportation, storage, safety, or other practical reasons. Consider the alternatives below:

  • Gas generation

    Gas is generated on demand. This may alleviate fire code limitations on the storage and use of these gases:

    • Oxygen
    • Hydrogen
    • Arsine
    • Fluorine
    • Methylsilane
    • Ozone

  • ---

    Subatmospheric gas cylinders

    Gas will flow out of the cylinder only if a vacuum is drawn on the cylinder valve outlet. Four types of systems are available that operationally meet this criteria:

    1. Gas adsorbed on a solid
    2. Gas complexed with a liquid
    3. Mechanical
    4. Gas generator
• References

  Requirements for engineering controls, protective equipment, storage, emergency response, warning systems, and employee training are based on:

  • Cal-OSHA General Industry Compressed Gas and Air Equipment 
  • Compressed Gas Association Hydrogen Safety Publications
  • Semiconductor Equipment and Materials International (SEMI) Facility Standards and Safety Guidelines
  • Occupational Safety and Health Administration Section 5(a)(1) – General Duty Clause
  • Occupational Exposure to Hazardous Chemicals in Laboratories (Laboratory Standard) California – Code of Regulations (CCR), Title 8, §5191
  • 2020 California Fire Code
  • NFPA 2 - Hydrogen Technologies Code
  • Compressed Gas Association Safe Hydrogen Project
  • National Fire Protection Association (NFPA) Standard 318 (Protection of Cleanrooms)
  • NFPA 55

Compressed Gas Safety Reference

• Classification and Requirements 
• Hazard Class Requirements Matrix
• Fume Hoods
• Hazard Controls
• Safety Resources for Individual Gases
• Shop Safety
• Storage & Handling
• Suppliers & Regulators
• Toxic and Hazardous Gas Classification