Features, advantages and applications in industrial systems

In medium- and large-scale flue gas evacuation systems — industrial plants, heating plants, power generators — the joining method between duct components plays a critical technical role. While in civil and residential installations the male-female socket connection with silicone gasket is the standard solution, in contexts requiring frequent disassembly, high tightness, scheduled inspections, or large nominal diameters, the flanged flue pipe and the corresponding flange joint represent the preferred technical solution. Understanding the construction features, available types, and correct applications of this joining technology is essential for professionals designing and managing flue systems.

What is a flanged flue pipe

A flanged flue pipe is a modular component in which the ends of the duct are equipped with flanges — flat metal rings with bolt holes — allowing mechanical connection with other flanged elements. Unlike socket systems, the flanged pipe is connected by bolting two opposing flanges together with a high-temperature gasket in between.

Flanges are typically welded to the pipe using TIG welding to ensure full metal continuity. Alternatively, loose flanges (rotating flanges) can be used to simplify alignment during installation.

Materials

Materials depend on flue gas characteristics: AISI 316L for corrosive environments, AISI 304 for standard applications. Carbon steel flanges may be used in large-diameter systems for cost efficiency when not in direct contact with flue gases.

Flange joint: operation and types

The flange joint connects flanged pipes or equipment. Tightness is achieved by compressing a gasket between flanges using bolts.

Advantages of flanged systems

Repeatable disassembly for maintenance and inspections
High-pressure resistance (up to class H1)
Connection versatility with standard flanged equipment
Ease of alignment during installation

Applications

Heating plants and industrial systems
High-pressure flue systems
Large-diameter ducts (>300 mm)
Systems requiring frequent maintenance
Connections to filters, silencers, heat recovery units
Modular or temporary installations

A professional solution

Flanged systems ensure reliability, durability, and compliance in demanding environments.

MT Camini offers stainless steel flanged systems with technical support for design and installation.

Flanged chimney pipe and flange joint