Chamflex

ChamFlex is a manufacturer of Class A fire-rated flexible hose assemblies for HVAC system connections, including water source heat pumps, fan coil units, variable air volume systems, and chilled beam applications. ChamFlex hose assemblies are tested to ASTM E84/UL 723 and carry a Class A fire rating, the highest fire-resistance classification in the standard. The inner tube compound carries a separate UL 94 V-0 flame rating. ChamFlex hoses are rated for a working pressure of 500 PSI and a temperature range of -40 degrees F to 212 degrees F, covering the full operating range of commercial HVAC hydronic systems. ChamFlex is a product line of Seal and Design, a manufacturing and distribution company operating across the United States and Canada. Mechanical contractors and HVAC installers specify ChamFlex where building codes require Class A fire-rated flexible connections in HVAC hydronic piping.

ChamFlex Product Lines

ChamFlex Swivel MNPT x Fixed MNPT Hose Assemblies

The ChamFlex Swivel MNPT x Fixed MNPT hose assembly is the standard configuration, featuring a swivel male NPT fitting on one end and a fixed male NPT fitting on the other. The swivel end allows the hose to be tightened to both connection points without twisting the hose body during installation, which is the primary advantage over fixed fittings on both ends. ChamFlex hoses in this configuration are available in 1/2", 3/4", 1", and 1-1/4" diameters and lengths including 12", 18", 24", and 36". The stainless steel wire outer braid is bonded to the inner tube through a patented process that minimizes kinking risk during installation and service access.

ChamFlex Inner Tube and Braid Construction

Every ChamFlex hose assembly uses an inner tube compound rated to UL 94 V-0, the highest flame classification in the UL 94 standard. The stainless steel wire braid outer layer is bonded to the inner tube through a patented manufacturing process that prevents the braid from separating from the tube body during flexing or installation. ChamFlex hose assemblies are not rated for potable water service; they're designed exclusively for closed HVAC hydronic circuits. The 500 PSI working pressure rating and -40 degrees F to 212 degrees F temperature range accommodate the full range of chilled water, condenser water, and low-temperature heating applications found in commercial HVAC systems. Where standard braided hoses may lack fire rating documentation, ChamFlex provides ASTM E84/UL 723 Class A test data to support code compliance submittals.

Size and Length Range

ChamFlex hose assemblies are available in four nominal pipe diameters: 1/2", 3/4", 1", and 1-1/4", covering the connection sizes found on fan coil units, water source heat pump equipment connections, and chilled beam supply and return ports. Standard stocked lengths include 12", 18", 24", and 36", allowing installers to match the hose length to the offset distance between the equipment connection and the building piping without field-fabricating custom assemblies. Longer assemblies may be available for special-order applications. The 1-1/4" diameter assemblies are specifically suited to larger fan coil units and water source heat pumps with higher flow requirements. Where the 1/2" and 3/4" assemblies cover residential and light commercial equipment, the 1" and 1-1/4" assemblies address commercial fan coil and heat pump applications with larger connection ports.

Why Contractors Specify ChamFlex

Mechanical contractors specify ChamFlex hose assemblies where building codes, inspection authorities, or project specifications require documentation of Class A fire rating on flexible HVAC connections. The ASTM E84/UL 723 Class A rating is confirmed through third-party testing, providing the submittal documentation that mechanical engineers and AHJs require. The UL 94 V-0 inner tube rating and stainless steel wire braid construction address both flame spread and smoke development requirements. The 500 PSI working pressure provides a substantial safety margin over the operating pressures found in commercial HVAC hydronic systems, which typically run at 60 to 125 PSI. ChamFlex hoses are available through SupplyHouse in the full range of diameters and lengths needed to complete a commercial HVAC fan coil or heat pump installation without custom fabrication.

How to Choose a ChamFlex Product

The primary selection variable for a ChamFlex hose assembly is pipe diameter. Match the ChamFlex nominal diameter to the connection port size on the HVAC equipment: 1/2" and 3/4" assemblies serve smaller residential and light commercial fan coil and heat pump connections; 1" and 1-1/4" assemblies serve larger commercial equipment with higher flow rates. Confirm the fitting thread type on both the equipment port and the building piping before ordering. All standard ChamFlex assemblies use MNPT fittings on both ends.

The second variable is hose length. Measure the straight-line distance between the equipment port and the building piping connection point, then add allowance for the offset and flex arc of the hose in the installed position. Standard ChamFlex lengths are 12", 18", 24", and 36"; select the shortest length that allows the hose to make the connection without kinking. Avoid specifying a hose length that requires the assembly to be stretched taut, as a fully extended braided hose cannot flex to absorb vibration.

ChamFlex hoses are not rated for potable water service. Confirm the system fluid is a closed HVAC hydronic circuit before specifying ChamFlex. For applications requiring potable water flexible connections, a different product is required. For fire rating submittals, request the ASTM E84/UL 723 test documentation from the distributor to include in the mechanical submittal package.

FAQs

Where are ChamFlex hose assemblies manufactured?

ChamFlex is a product of Seal and Design, a company with manufacturing and distribution operations across the United States and Canada. For specific manufacturing location, contact Seal and Design directly or consult the product documentation.

What fire rating does ChamFlex carry?

ChamFlex hose assemblies are tested to ASTM E84/UL 723 and carry a Class A fire rating, which is the highest classification in that standard for flame spread and smoke development. The inner tube compound also carries a UL 94 V-0 flame rating. Both ratings are available in the product documentation for code submittals.

What is the difference between ChamFlex 1/2" and 3/4" hose assemblies?

The difference between ChamFlex 1/2" and 3/4" hose assemblies is the nominal pipe diameter and corresponding flow capacity. The 1/2" assembly is sized for smaller equipment connections in light commercial and residential fan coil applications; the 3/4" assembly handles higher flow rates for larger equipment. Both carry the same 500 PSI working pressure rating, Class A fire rating, and MNPT swivel x fixed fitting configuration.

What is the maximum working pressure for ChamFlex hose assemblies?

ChamFlex hose assemblies are rated for a maximum working pressure of 500 PSI. Commercial HVAC hydronic systems typically operate at 60 to 125 PSI, placing ChamFlex well within its rated working pressure range for standard HVAC applications.

Are ChamFlex hoses compatible with chilled water systems?

ChamFlex hose assemblies are rated for a temperature range of -40 degrees F to 212 degrees F, which covers standard chilled water system operating temperatures. ChamFlex is not rated for potable water service but is designed for closed HVAC hydronic circuits, including chilled water, condenser water, and low-temperature heating systems.

What lengths and diameters does ChamFlex offer?

ChamFlex hose assemblies are available in 1/2", 3/4", 1", and 1-1/4" nominal diameters and standard lengths of 12", 18", 24", and 36". The combination covers the connection sizes and offset distances found in most commercial HVAC fan coil, water source heat pump, and chilled beam installations.