Customers often ask about the temperature and pressure ratings of our tri-clamp fittings. Occasionally, they will be working in processing environments where high temperatures, pressure or both are required. Naturally, the question arises about our fittings and their ability to withstand both. You’ve no doubt heard the saying: “A chain is only as strong as its weakest link.” The same logic applies for tri-clamp fittings.
Tri-clamp fittings are weakest at the connection points where one flange ferrule connects with another. At this point, there is a gasket and clamp used to connect the two fittings in place. This point represents the weak link in the chain for both pressure and temperature. In the case of higher pressures, it’s the clamp that can fail. With regard to temperatures, the gasket will fail before anything else.
Below are two tables to reference for both clamps and gaskets regarding temperature and pressure ratings. In the case of clamps, we have selected our strongest clamp, the double-bolt high-pressure clamp. Displayed are the recommended pressure ratings in Pounds per Square Inch (PSI) at varying temperatures.
Gasket Temperature Ratings
|Buna (Nitrile)||Standard: -35°F to 250°F (-37°C to 121°C)|
|EPDM (Ethylene Propylene)||Standard: -65°F to 300°F (-54°C to 149°C)|
|PTFE (Teflon®)||Standard: -250°F to 450°F (-157°C to 232°C)|
|FKM (Viton®)||Standard: -15°F to 437°F (-26°C to 222°C)|
Double Bolt High-Pressure Clamp Ratings
|Size (Tube OD)||Part Number||Service Pressure Rating at 70°F||Service Pressure Rating at 250°F||Dimensions|
|1/2 – 3/4″||13MHP-050-075||1500||1200||1.062|
|1″ – 1-1/2″||13MHP-100-150||1500||1200||2.046|
With all this being said, we have put together a theoretical tube burst schedule in the table below. It is theoretical because the true burst pressure of these tube fittings cannot be accurately measured without a way to properly seal them off.
Theoretical Tube Burst Pressure Ratings
|Size (Tube OD)||Dimensions||Burst Pressure (PSI)|
- Working pressure is 25% of Burst Pressure in temperatures ranging from -20°F to 100°F
- The ASME code suggests a safety factor of four (4). (eg. 1″ x 0.065 = 2,438PSI)
- The information presented above are average values and not a guarantee of maximum values.
If you have any other questions, please call or email for additional information.