Design considerations for Sudbury International joints: movement, flange

Expansion joints from Sudbury International are perfect for industrial ducting systems.

Sudbury International Engineered Products Limited supplies ducting-system expansion joints for several industries. When manufacturers design these components, many aspects must be considered for top performance and reliability. Two important criteria are typical movement capabilities and flange height. Optimizing the performance of these factors will result in expansion joints that get the job done and make businesses more competitive.

Multiple movements in one unit

After laying out the supporting structural steel and ducting systems, a manufacturer of ducting-system expansion joints should locate ducting anchor points to calculate the ducting movements at both the design and maximum excursion temperatures, as well as any mechanical and structural drift and seismic and wind effects that affect the operation of the joint assembly.

Expansion joints by Sudbury International can handle combined axial, lateral, angular, and torsional movements within one unit. Joint locations should be chosen carefully, to keep the number of joints in the system to a minimum and still absorb all duct movement. If a joint location has very large axial and/or lateral movement, the manufacturer can recommend how to handle it.

After determining all movements and expansion-joint locations, manufacturers should select the proper joint geometry for the application. The breach opening required at each location depends on the movement criteria and the geometry chosen.

Also important to consider is the active length of the flexible element. Increasing the active lengths of ducting-system expansion joints enables accommodation of greater movement. The amount of extra material must be considered when figuring the joint’s lifespan.

When establishing the dimensions of the flexible-element mounting surfaces, manufacturers must consider setback and flange height. Setback is the distance that the flexible element moves outward from the gas stream to allow for system movements and prevent the joint from protruding into the gas stream or rubbing the flow liner when operating under negative pressures.

The minimum flange height/width for the integrally flange type is three inches, although this dimension changes with the system movement to ensure correct setback. Manufacturers consider flange height plus the recommended setback to determine the overall mating duct flange height.

For more information, contact Sudbury International.

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