Understand key hazards and apply proper storage and handling practices
By Marie Anstead, vice president of health, safety, environment, and industrial management system for Airgas SAFECOR, Houston, Tex.
Safety is paramount in any welding operation, from small fabrication shops to large manufacturing plants. While welders are aware of the health hazards of fumes and radiation, as well as the safety hazards of burns and eye damage, compressed gases present their own unique risks. All compressed gases are regulated as hazardous materials, making it critical to understand their properties and strictly follow safety rules.
In this article, tips and best practices are provided for the safe storage and use of welding gases, based on guidelines from the Occupational Safety and Health Administration (OSHA). The article also covers the basics of cylinder handling and explains how modern shielding gas blends and cylinder technologies can simplify processes, enhance performance, and improve safety on the shop floor.
Understanding the Hazards before Starting
To ensure the safety of your operation, always confirm a cylinder’s contents by reading the label and stenciled or stamped markings. Never rely on a cylinder’s color or interchangeable tags. If a label is missing or illegible, mark the cylinder as “contents unknown” and contact the manufacturer for safe return. For complete hazard information, refer to the safety data sheet (SDS), which utilizes the Globally Harmonized System for precise classification. Understanding the contents of the cylinder and the information on the SDS is essential, as each gas presents specific risks categorized into physical and chemical hazards that must be managed during storage and handling.
In addition, refer to AWS Safety & Health Fact Sheet No. 30, Cylinders: Safe Storage, Handling, and Use, accessible at aws.org/standards-and-publications/free-resources.
Main Physical Hazards
Below are the primary physical hazards: pressure, weight, and temperature.
Pressure. Stored energy within a compressed gas cylinder presents a significant risk of forceful propulsion if the valve is damaged. Secure the valve protection cap when not in use.
Weight. Cylinders can cause crushing injuries if dropped or unsecured.
Temperature. A rapid release of contents can cause a cryogenic burn (similar to frostbite).
Three Types of Chemical Hazards
This section outlines three types of chemical hazards: inert and flammable gases and oxidizers.
Inert Gases (e.g., argon, helium). Nonflammable and nontoxic, these gases are simple asphyxiants. A leak in a poorly ventilated area can displace oxygen, leading to oxygen deprivation and creating a dangerous situation that can go undetected due to the gases’ colorless and odorless nature.
Flammable Gases (e.g., acetylene, hydrogen). These gases burn when mixed with an oxidant and an ignition source, such as a flame or a spark. Keep all ignition sources far away.
Oxidizers (e.g., oxygen, nitrous oxide). Oxidizers don’t burn on their own but dramatically accelerate the burning of other materials. Never store them near flammable materials, such as oil or grease.
Federal and state regulations mandate specific training for anyone handling compressed gases. Always read and understand the SDS for any gas before use.
Optimal Methods for Cylinder Storage
Proper storage is the first defense against gas-related incidents and catastrophic failures. Refer to osha.gov/laws-regs/regulations/standardnumber/1926/1926.350 for current OSHA guidelines.
Keep Gases Separate
OSHA requires flammable cylinders to be stored at least 20 ft from oxygen and other oxidizers or separated by a noncombustible wall that is 5-ft high with a 30-min fire rating. It’s also wise to store poisonous and toxic gases separately and to keep full and empty cylinders apart.
Create a Safe Storage Space
Storage areas must be well ventilated, dry, and protected from weather. Never store cylinders where water can accumulate, as it may cause the bottom of the cylinder to corrode over time. Keep cylinders away from heat, sparks, open flames, and electrical circuits. Compressed gas cylinders must not be exposed to temperatures higher than 125°F (52°C) (refer to CGA P-1, Standard for Safe Handling of Compressed Gases in Containers), as extreme heat weakens cylinder walls. Additionally, consider installing gas detection monitors in storage areas, especially for inert gases, such as argon. As simple asphyxiants, these odorless, colorless gases can quickly displace oxygen. Monitors set to alarm below a safe threshold (19.5% O2) are an essential early-warning safeguard against this silent hazard.
Secure Every Cylinder
Always secure cylinders upright with a chain, strap, or clamp to prevent falling. The valve protection cap must be on tight when the cylinder is not in use unless it has a permanent protective guard.
Tips for Safe Cylinder Handling and Use
Once a cylinder moves from storage to the point of use, new protocols apply.
Inspect Before Use. Check the label for readability and the valve for dirt, oil, or damage. Never use a cylinder containing an oxidant if oil or grease is present on the valve, as this can create an explosive combination.
Make Proper Connections. Use only regulators and fittings specifically designed for the gas and pressure in question. Never force mismatched threads. Do not use Teflon® tape to fix valve thread leaks, as it can break apart and damage the regulator.
Initiate Gas Service Safely. After securing the cylinder, stand away from the front of the regulator and open the cylinder valve slowly. Once pressurized, use a compatible leak-detection solution to check all connections for leaks.
Transport Cylinders the Right Way. The safest way to move a cylinder is with a purpose-designed hand truck or cart. Never lift a cylinder by its cap or valve. Do not transport cylinders in enclosed vehicle spaces, such as car trunks or vans, as a leak risks explosion, fire, or asphyxiation.
Shielding Gas Selection: Simplifying for Safety
With many shielding gas blends available, selection can be complex, introducing risk. Using the wrong gas can lead to poor weld quality, increased fume generation, or unsafe arc characteristics.
Simplifying this choice significantly improves safety. For example, the Airgas ARCAL™ line of shielding gases was designed to simplify 85% of welding applications into five high-performance gas blends. Each blend is precisely mixed to exceed AWS A5.32M/ISO 14175, Welding Consumables — Gases and Gas Mixtures for Fusion Welding and Allied Processes, tolerance requirements. Modern cylinder technology also incorporates safety features as built-in engineering controls; for example, ARCAL cylinders feature valves offering multiple layers of protection.
Ending Thoughts
Managing welding gases safely is an ongoing responsibility requiring knowledge, good habits, and the right equipment. By understanding inherent gas hazards, strictly adhering to OSHA-compliant storage and handling procedures, and leveraging simplified gas selection systems and innovative cylinder technology, fabrication shops can significantly reduce risk. A strong safety culture prevents accidents, fosters professionalism, and ensures that every weld is both strong and safely made.