Flanges for Building HVAC Systems
Low-pressure flanges engineered for chilled water loops, steam systems, and condensate lines in modern building mechanical applications.
Reliable Fluid Handling for Climate Control
HVAC systems demand reliable, cost-effective flanges for chiller loops, boiler systems, steam distribution, and condensate return lines. ApiFlange supplies ASME-compliant low-pressure flanges in carbon steel and ductile iron, with companion flange and grooved connection options for modular building systems. From retrofit projects to new construction, our HVAC solutions ensure efficient, leak-free climate control infrastructure.
Chilled Water
150 psi Class
Steam Ready
250+ psi rated
Cost-Effective
Standard materials
Quick Install
Grooved options
Pressure Classes for HVAC Service
Standard ASME Classes
150 psi
Chilled water loops (typical)
to 350°F
300 psi
High-efficiency chillers
to 400°F
600 psi
Boiler systems
to 500°F
Typical HVAC Applications
- ✓Centrifugal chiller connections
- ✓Steam boiler outlet nozzles
- ✓Pump discharge flanges
- ✓Heat exchanger connections
- ✓Expansion tank ties
- ✓Strainer bowl connections
Flange Types for HVAC
Slip-On Flanges
Most common HVAC choice, cost-effective, field-weldable for retrofit applications.
Companion Flanges
Bolted to grooved pipe fittings, eliminates welding, fastest installation method.
Blind Flanges
System end caps and isolation block-offs, readily available in all sizes.
Reducing Flanges
Size transitions with minimal turbulence, smooth flow paths for efficiency.
Materials & Coatings
HVAC applications typically use standard carbon steel or ductile iron flanges, which offer excellent cost-to-performance ratio for low-pressure service.
Carbon Steel
- •ASTM A105 standard
- •Excellent weldability
- •Cost-effective
- •Typical selection
Ductile Iron
- •ASTM A536 Grade
- •Impact resistant
- •Broader temperature
- •Alternative option
Surface Treatment
- •Mill finish standard
- •Galvanizing available
- •Paint-ready options
- •Corrosion protection
Size Range & Specifications
ApiFlange stocks HVAC flanges in all common building sizes, from small instrument connections to large distribution headers.
Standard Available Sizes
½" to 36"
Slip-on, companion, blind configurations
Ready to Specify Your HVAC System?
Our HVAC specialists can help you select the right flange sizes and pressure classes for your chilled water, steam, or condensate systems.