March 2005

In keeping with Air Products' commitment to Product Stewardship and Responsible Care®, this bulletin has been written to inform customers of a potential safety concern associated with certain proportional relief and check valves of inlet connection sizes ¼" and smaller, used in many safety relief applications.
 
Test data and experience show that for some safety relief applications, these valves may not open.  We recommend that you determine whether you have any of these valves in your equipment in safety relief applications and take appropriate action if you do. There are various measures you may adopt to ensure acceptable levels of safety with regard to this issue. These measures include replacement of the subject valves, addition of rupture discs to the systems, the use of protective barriers and safety shielding at critical pressurized components, and other measures further detailed in the Frequently Asked Questions.

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

Proportional relief and check valves used as safety relief valves that are of concern are listed below:

• Swagelok® (Nupro) type C check valves at set pressures less than 100 psig
• Swagelok® (Nupro) type CA check valves at set pressures less than or equal to 250 psig
• Swagelok® (Nupro) type CPA check valves at set pressures less than or equal to 100 psig
• Swagelok® (Nupro) type R3A proportional relief valves at set pressures less than or equal to 1000 psig
• Swagelok® (Nupro) type RL3 proportional relief valves at set pressures less than or equal to 10 psig
• Circle Seal 500 series relief valves at set pressures less than or equal to 10 psig

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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