January 2002

Air Products and Chemicals, Inc. (Air Products) is committed to the safety of its employees and customers. As a part of its commitment to Responsible Care® and Product Stewardship, Air Products keeps customers and others informed of significant changes in or new information about the properties, safe handling, and use of its products. In continuing with our safety philosophy, we would like to take this opportunity to inform you of a potentially critical safety issue involving the use of certain torches without check valves that provide back-flow protection. We encourage you to communicate this with your employees.

Back-contamination of cylinders is a problem that is associated with all containers. This dangerous condition most commonly occurs when one cylinder gas empties during operation, consequently creating an imbalance of pressure into the system. Back-flow contamination can also occur from a clogged or blocked torch tip. In either case, the higher pressure gas can cause the lower pressure gas to reverse flow back toward the lower pressure container. If this reverse flow is not stopped, the gas can flow back into the cylinder and create a flammable explosive mixture, which if ignited, can potentially cause equipment damage and/or personal injury or death.

In order to reduce the risk of back flow contamination, Air Products will only sell torches equipped with some type of back-flow protection; either equipped with a check valve or a built-in flashback arrestor and check valve.

For your own safety and the safety of your employees, please check your existing torches prior to use to ensure that they have some type of back-flow protection. In addition to ensuring that back flow protection is functional, please ensure that you are performing preventive maintenance in accordance with the torch manufacturer's recommendations.

If you have any questions, which are not answered by these materials, please contact your local Air Products Welding Specialist or our Technical Information Center at (800) 752-1597 from 8 a.m.–5 p.m. EST.

Thank you for your prompt attention to this matter.

Contact the Air Products Technical Information Center:
For technical data, product specifications, safety and environmental information, and applications assistance:

Call 1-800-752-1597 (U.S.)
Call 1-610-481-8565 (other locations)
Fax 1-610-481-8690
Email gigmrktg@airproducts.com
Monday–Friday, 8:00 a.m.–5:00 p.m. EST

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