When Mueller Streamline, a subsidiary of Mueller Industries, expanded its XHP Copper-Fittings product line for CO2 (R744) refrigeration applications last year to include 2-⅝in (6.67cm) outside-diameter fittings – its largest to date – the reception in the U.S. was positive.

Before the release of the larger-sized fittings, the largest XHP copper alloy fitting Mueller Streamline offered was 2-⅛in (5.4cm).

“The 2-⅛in [fitting] wasn’t big enough in the States,” said Chris Mueller, Vice President of Mueller Streamline, in an interview at the AHR Expo, held in Atlanta, Georgia, February 6-8. He added that a major U.S. transcritical CO2 system OEM was “all over me for a long time to produce a bigger fitting.” Mueller Streamline released the bigger size last summer, and the reception has been “fantastic,” he said.

“A lot of the systems and stores in the U.S. are bigger than those in Europe,” said Mueller, adding that not having 2-⅝in XHP tube and fittings was “a real problem” in the U.S.

The 2-⅝in fittings are designed for continuous 130bar (1,884psi) pressure ratings at 120°C (248°F) and have commercial, industrial and other applications. “It just depends on how much cooling they need,” said Mueller. Moreover, in the past, systems using larger piping had to rely on stainless-steel fittings. “The larger-sized fitting presents an opportunity to stay with a copper alloy,” he said.

Made from material in compliance with C19400 grade of copper alloy, the XHP line was developed for use with high-pressure refrigerants like CO2. The Mueller Streamline XHP fittings are a brazed connection product and range in size from ⅜ (0.95cm) to 2-⅝in. The fittings are available in tees, elbows, rolled-stop couplings, reducing couplings, fitting reducers and caps.

Founded in 1930, Mueller Streamline (headquartered in Collierville, Tennessee) is an integrated manufacturer and distributor of piping system solutions. Along with copper tubing and fittings, the company manufactures valves and other items for plumbing, HVACR applications, refrigeration, medical gas and other systems.

Mueller Streamline’s offerings also include a ball valve series designed by Mueller Refrigeration to address the market requirements for operating pressures and temperatures above the critical point for CO2.

“The 2-⅛in [fitting] wasn’t big enough in the States.”

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