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Trade Skills HVACR116. Sheet Metal. Sheet Metal. The most common types of duct material are: Aluminum Fiberglass duct board Spiral metal duct Flexible duct All of these types of materials have been used successfully. Sheet Metal (cont.).
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Trade Skills HVACR116 Sheet Metal
Sheet Metal • The most common types of duct material are: • Aluminum • Fiberglass duct board • Spiral metal duct • Flexible duct All of these types of materials have been used successfully
Sheet Metal (cont.) • The first type of metal going to be discussed is Galvanized-Steel Duct • This particular metal is treated with a zinc coating to keep the steel underneath from corroding. • Galvanized sheet metal comes in different thicknesses that are known as gauge.
Galvanized-steel Duct As the gauge number gets larger, the thickness of the sheet metal gets thinner. • Ex. 30-ga galvanized sheet metal is 0.0157 inches thick, while 22-ga galvanized sheet metal is 0.0336 inches thick. • Notice that the 22-ga metal is about twice as thick as the 30-ga
Sheet Metal • Sheet metal thickness is directky related to its weight. • The Standard Gauge for Sheet Metal is 41.82 lb/ft2. • This is a common factor, when multiplied by the thickness of the metal. You will get the weight of one square foot of the metal.
Ex. The thickness of 24-ga metal is 0.0239 in. • Ex. The weight of 1 ft2 of this material is 1 lb • lb=(0.0239 inches x 41.82 lb/ft2) • Lb=.99 or 1
Sheet Metal (cont.) • Ex. Lb=(0.012 inches x 41.82 lb/ft2) • Ex. Lb=
Fiberglass Duct • Fiberglass duct is also known as Duct Board. • Fiberglass duct comes in 2 different styles • Flat sheets • Round prefabricated duct
Fiberglass Duct (cont.) • Fiberglass Duct Flat Sheets
Fiberglass Duct (cont.) • Round Prefabricated duct
Spiral Metal Duct • Spiral duct is used on large sytems. • The duct is formed from flat metal and has seams all the way down the duct. • It comes in 10’ lengths
Flexible Duct • Flexible duct also known as Flex, comes in sizes up to 24 inches in diameter. • Some of flexible duct comes with or without insulation. • Flexible duct comes in 25’ lengths. • Code only allows us to run a maximum of 14’ per run out.
Flexible Duct (cont.) • Uninsulated
Flexible Duct (cont.) • Insulated