Compressed gases are gases or mixtures of gases stored in a container at a pressure significantly higher than atmospheric pressure, typically defined as exceeding 40 psi at 70°F (21°C), meaning it is kept under high pressure compared to its normal state; essentially, a gas that has been forcefully squeezed into a smaller volume. Due to their high pressure, compressed gases can pose safety hazards if not handled properly.
Compressed gases can be toxic, flammable, oxidizing, corrosive, or inert. In the event of a leak, inert gases can quickly displace air in a large area creating an oxygen-deficient atmosphere, toxic gases can create poison atmospheres, and flammable or reactive gases can result in fire and exploding cylinders. In addition, there are hazards from the pressure of the gas and the physical weight of the cylinder. A gas cylinder falling over can break containers and crush feet. The cylinder can itself become a missile if the cylinder valve is broken off.
The Rensselaer Compressed Gas Cylinder program provides guidance to compressed gas users to comply with federal and state regulations pertaining to compressed gases in research at Rensselaer. In addition, the program guides compressed gas users on chooses the correct tools when setting up gas cylinders in a laboratory or workshop.
RPI Compressed Gas Cylinder Program
The purpose of Rensselaer Polytechnic Institute's Compressed Gas Cylinder Program is to provide safety guidelines designed to manage the proper handling, storage, and use of compressed gas cylinders within laboratories and workshops.
Hazards associated with compressed gases can be attributed to the physical or chemical characteristics of the gases. Importantly, all compressed gas cylinders also pose physical hazards due to the potential energy of the compressed contents.
Chemical properties of compressed gases include flammability, cryogenic, reactivity, toxicity, corrosivity, or asphyxiants, and some possess all or a combination of these hazardous properties as well as others. Consult the Compressed Gas Cylinder Program for specific information on how to handle different compressed gases.
Proper storage is essential for the safe use of compressed gases. In general, compressed gas cylinders must be stored in an upright position within a well-ventilated area, whether full or empty. Also, gas cylinders should always be secured in an upright position except, if necessary, for short periods of time while cylinders are actually being moved.
Gas cylinders should not be stored near elevators or gangways, or in locations where heavy moving objects may strike or fall on them. They should be stored away from heavy traffic, emergency exits, or places that subject them to tampering by unauthorized persons. Gas cylinders should not be stored in hallways and objects should not be stored on top of gas cylinders.
When the gas cylinder is not in use, ensure that the valve is closed, the regulator is removed, and the valve protector cap is secured in place. “In use” gas cylinders are defined as a gas cylinder connected through a regulator to deliver gas to a laboratory operation, connected to manifold being used to deliver gas to a lab operation, or a single cylinder secured alongside the gas cylinder to use as a reserve gas cylinder.
Gases with the same hazard class should be stored in the same area. Inert gases are compatible with all other gases and may be stored together. Segregate gas cylinders by hazard classes while in storage. When there is a need for mixed storage, store gas cylinders only with other compatible gases.
The following best management practices should be used to minimize the amount of compressed gas located in your workplace:
- Substitute, if possible, with a gas that is less hazardous.
- Limit the amount of hazardous compressed gas to that which is deemed necessary.
- Minimize the quantity of compressed gases on hand using the following strategies:
- Maintain the smallest quantities of compressed gases possible
- Have no more than one back up cylinder of each gas
- Use just-in-time delivery
- Record all compressed gases in your lab’s chemical inventory, including non-hazardous gases.
Compressed gases must be handled by properly trained persons. Training must include the information presented in this program as well as any specific information relevant to the gas being used.
- To handle gas cylinders safely:
- Never drag or physically carry cylinders (lecture cylinders may be carried).
- Never pick cylinder up by the cap.
- Never paint a cylinder.
- Never leave cylinders in areas where they will be subject to damage from falling objects, corrosion or public tampering.
- Never subject cylinders to artificially created low temperatures without approval from the supplier.
- When lifting and moving cylinders, the following precautions should be taken to keep yourself safe:
- Wear hard-toed shoes.
- Use a hand-truck designed for the transport of cylinders.
- Secure cylinder caps during transport.
- Cylinders are prohibited to be transported in any vehicle on RPI’s campus. If special transportation is needed, please contact EHS for assistance.
- When a cylinder needs to have elevator transport:
- Do not accompany a compressed gas cylinder in the elevator.
- Place the cylinder in the elevator and press the destination floor. Take the stairs and meet the cylinder on the destination floor.
- A buddy system may be employed by having one person load the gas cylinder on the elevator and a second person receive the gas cylinder on the destination floor.
- Attach a sign to the cylinder, telling others not to use the elevator during the cylinder’s trip.
Compressed Gas Association CGA P-20 (Classification of Toxic Gas Mixtures) and P-23 (Categorizing Gas Mixtures Containing Flammable and Nonflammable Components)
National Fire Protection Association (NFPA) documents:
- NFPA 45: Standard on Fire Protection for Laboratories Using Chemicals, 2019 Edition
- NFPA 55: Compressed Gases and Cryogenic Fluids Code, 2020 Edition
TechAir Regulator Change Out Procedure and Operating Instructions
