Standard Hvac Duct Length

Rectangular duct and fittings are one part of our complete line of hvac products.

Standard hvac duct length.

All ductwork comes standard with stiffening beads. Do that for all the ducts and branches on the table. Information required for duct construction 1. 1 psi equals 27 7 inches of water gauge.

Before sizing a duct system we have to lay out all the ducts. Installing the duct incorrectly will affect the heating capacity of the system as much as improper sizing. Adding up all the lengths and effective lengths. And that my friend is the definition of effective length.

Run the correct size from the furnace and be sure they are installed correctly. The duct size must adequately handle air flow intake and return in order for an hvac system to operate at optimal levels. Design cfm 4 cfm 6 cfm 8 cfm 10 cfm 12 60 6x4 60 4x6 90 4x8 120 4x10 150 4x12 90 8x4 110 6x6 160 6x8 215 6x10 270 6x12 120 10x4 160 8x6 230 8x8 310 8x10 400 8x12 150 12x4 215 10x6 310 10x8 430 10x10 550 10x12 180 14x4 270 12x6 400 12x8 550 12x10 680 12x12 210 16x4 320 14x6 490 14x8 670 14x10 800 14x12 240 18x4 375 16x6 580 16x8 800 16x10 950 16x12 270 20x4 430 18x6 670 18x8 930 18x10 1100. Smc manufactures coil line ductwork in 4 5 6 lengths.

Now find the total duct losses for each duct and branch that s very easy to do simply multiply the duct length by the pressure drop per meter in our example we found it to be 0 65pa m. A comprehensive duct layout indicating sizes design airflows pressure class and routing of the duct system. A common duct pressure of 0 25 inches water column is equal to 0 25 divided by 27 7 in wc psi 0 009 psi. Sizing ducts for a heating system is a complex task.

Rectangular single wall duct ductwork fittings. The types of fittings to be used based on the designer s calculations of fitting losses i e square versus 45 entry taps conical versus straight taps etc. In the duct design process however it s more convenient to categorize these pressure drops by the length of straight duct run that would create the same pressure drop. It involves the heat output of the unit measured in british thermal units the air flow from its blower the number of vents and their location and the length of ducts needed to reach those vents.

Smc tdc slip drive and raw sheet metal connectors inc. Once all the rooms are considered for duct size calculations increase the duct size accordingly. Duct system is pressurized by three pressures. Equivalent diameter rectangular and circular hvac ducts equivalent diameter for rectangular and circular ducts air flows between 100 50000 cfm.

Ordinary heating ventilating and air conditioning duct systems read air pressures at 0 4 psi or less often much less. Install the appropriate duct size connections.