Floor Trusses Hvac Chase

Design criteria for the 4 x 2 floor system.

Floor trusses hvac chase.

Ducts in a special roof truss. Floor trusses can span farther between bearing points than i joists allowing for larger open rooms. There simply wasn t a way to get from the mechanical room to the other end of each floor using metal. The resulting chase is variously called a raised hvac coffer and an inverted soffit.

Alpine engineered products now itw referred these to floor trusses as system42 trusses. Hvac chases in floor trusses hvac chase. Hvac chases are typically 24 wide and as tall as the height between the top and bottom chords will allow. Open web design leaves plenty of room for mechanical systems hvac plumbing electrical to be installed within the floor frame.

I specified open web trusses for my new house in part to simplify the installation of mechanical systems. This also reduces the need and cost for extra bearing posts beams and footings. Maximum span to depth ratio of 1 to 20 example 14 truss should not exceed 23 4 span spacing may be adjusted to accommodate longer spans maximum 24 duct chase on flat wise trusses minimum duct chase offset from the bearing is of the span. For a standard 4x2 floor truss meaning warren style webs with 30 inch panels with double cut webs the maximum round duct in the end panel is 5 625.

Floor trusses have built in openings which can be used to install hvac ductwork plumbing lines and electrical wiring. I was annoyed that the truss company had not included a clear path for running metal ducts. Open joist is a revolutionary open web all wood floor truss engineered with superior strength and load carrying capabilities. See sbca s ttb floor truss fact sheet.

Recently i discovered that the truss system would not support metal ducts. Hvac chases or duct runs may be designed into floor trusses to allow for plumbing and or heating and air conditioning ducts to be installed in the floor. Floor trusses go by many names and since parallel chord 4x trusses can be used in roof systems the term floor truss is not necessarily the most accurate term although it is the one in most common use. Stuart lewis from alpine engineered products tells us.

It s possible to order special roof trusses called plenum trusses designed to accommodate a duct chase near the attic floor. Most truss manufacturers can produce custom plenum trusses that include an integral duct chase.