Best prices guaranteed. We match other Aussie retailers*. Use our sizing calculator below to determine the minimum size required for your room or house. Remember for ducted systems only include the air conditioned spaces, exclude areas like …Air flow rates: information is provided on recommended air flow rates for each duct size. These flow rates are related to the volume of air needed for the HVAC system to maintain thermal comfort and air quality. Air speed: the graph illustrates the air speeds that can be obtained for the different dimensions of the ducts and air flow rates. A rectangular 6×6-inch duct has an airflow of 110 CFM. Bigger 6×12-inch ducts can handle 270 CFM airflow. The bigger the crosssection of ducts, the bigger CFM; that’s pretty obvious. The smallest 6×4 ducts can handle 60 CFM airflow. The biggest 42×12 ducts with 504 sq inch crosssection can handle 3000+ CFM airflow. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ... TO CALCULATE DUCT SIZE: Enter Air Quantity (Flow Rate) Enter either Friction Loss or Velocity. The software will automatically detect the calculation method. Click Calculate and refer to duct size box for results. Click Refresh for a new calculation. Duct Calculator Elite TM is an industry leading tool designed to simplify the job of duct sizing for HVAC professionals. This app allows users to calculate duct size, velocity, pressure drop, and flow rate for ductwork . Duct Calculator Elite TM features a highly intuitive interface which allows users to easily enter values with precision (without the …HVAC Charts - Your Source for Heating & Air Conditioning Charts and Supplies. Duct Sizing Calculator. The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct ...JP Lamborn Co. ( JPL ) began producing flexible air ducts in 1961. Today the company operates four state-of-the-art manufacturing facilities and is the largest family-owned flexible air duct manufacturer in North America. JPL’s core values of manufacturing high-quality products, providing excellent service, innovation, and strong business ...While air duct cleaning and repair lengthens its life span, ductwork typically needs major replacement every 15 years to work properly. The national average cost for full ductwork replacement is $1,450–$8,000; however, the cost can range anywhere from $250–$12,000 depending on home size, system accessibility, and materials used.Instructions. (Input information may generally be be obtained from design documents or field measurements) Line 1. Enter the temperature of the air entering the duct. Line 2. Enter the ambient temperature (the average temperature of the air surrounding the duct) Line 3. Enter the flow rate of the air carried by the duct in cubic …The ASHRAE Duct Fitting Database (DFDB) app allows you to perform pressure loss calculations for all 200+ ASHRAE duct fittings in both I-P and SI units. Use this mobile app in the field for quick duct pressure loss calculations. The inputs can be adjusted by touch, and installation is automatic. Available via iTunes®, the app is now universal ...About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ...The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct size, weight per linear foot of round duct, surface area in square feet per lineal foot of round duct ...A good HVAC duct sizing rule of thumb is to measure rooms in your home, the necessary airflow rates, and friction loss rate. Using these numbers you can calculate the appropriate HVAC duct size. For example, a one-to AC system typically uses 10-inch ducts, while a 4-ton AC system requires 18-inch ducts. There are several variables to …ADI DUCTULATOR. Based on research conducted by Texas Tech University as well as Tennessee Tech University, to study the efect of compression in flexible duct on air flow efficiency, ADI created the Ductulator. This Duct Size Calculator's data is based on flexible duct laying in a straight line on a level surface,and nearly fully stretched (4% ...To adequately calculate the speed of air in ducts, we have to primarily calculate the cross-section of the duct. Shape-wise, ducts can be: Round. The area of round flex ducts is calculated as π*R 2 where R is the radius of the duct. Example: 10-inch round duct has a radius of 5 inches.QUICK-GUIDE. Select the duct material from the drop-down list (most duct sizing tools are typically based on galvanised steel ducting by default) Enter the air flowrate in litres/second (can change to cubic metres/second by …A simple volume unit converter to convert air flow volumes from ... Calculate the equivalent size of spiral ducting when you have only been given the rectangular duct dimension (it works the other way also) Open the ES Calculator. System Pressure Calculator. The System Pressure Calculator helps you work out the resistance in pascals that ...An HVAC duct calculator or ductulator is a tool that can be used to calculate the ideal size of your HVAC ducts. It factors in the area size and temperature, air flow velocity, friction loss, and static pressure of the HVAC system. Duct-U-Lator. This app works as a Ductulator and Pressure Loss (friction) calculator which has the following functions. Converts Duct Shape or Size to Another. Determines Sizes for a Given Friction Rate. Determines Sizes for a Given Velocity. Determines Sizes for a Given Velocity and a Friction Loss Rate (simultaneous output) Duct type: Metal Ductboard Flex Size by: Friction rate Velocity Friction Rate: per 100 ft. in/wg Duct TEL : ft. * include fittings in the Duct TEL Enter either: CFM: or Duct Size: …Air Duct Calculator. Double-sided. Side 1 = standard ducloator with calculations for both round and rectangular duct. Side 2 = Continental vs competitive cross reference for some common GRDs and a Grille sizing chart. Qty 25/package.About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ...Nov 7, 2022 · To calculate the speed of air in the ducts, we use a duct velocity calculation (you can find the calculator below). Let’s first look at how to calculate the air velocity in the ducts. We have to use this air velocity formula in restricted spaces (such as ducts): V (Air Velocity) = Q (Airflow) / A (Duct Cross-Section) The equivalent diameter of a rectangular tube or duct can be calculated as (Huebscher) de = 1.30 (a b)0.625/ (a + b)0.25(1) where. de = equivalent diameter (mm, inches) a= length of major or minor side (mm, inches) b= length of minor or major side (mm, inches) Hydraulic diameter - the "characteristic length" used to calculate the dimensionless ...To calculate the kinematic viscosity of air at pressure 1 bar (105 Pa) and 50 °C, enter a few details into the kinematic viscosity of air calculator: Convert the temperature in Celsius to kelvin: T = 273.15 K + 50 = 323.15 K. Calculate the density of the air from the ideal gas law: ρ = P/ (RT) = 105 Pa/ (287.05 J/kg·K × 323.15 K) = 1.078 kg/m3.AIR DUCT CALCULATOR : by Michael J. Rocchetti PE Mechanical Engineer . Metric Units. Flow rate M^3/S: Velocity M/S: Pressure Pascals: Temperature C: Length Meter: Duct Material: Uncoated Carbon Steel: PVC Plastic Pipe (smooth) Aluminum (smooth) galvanized steel (medium smooth) galvanized steel (average smooth) fiberglass duct …A 4 feet air duct with diameter 2 inch and air flow volume 156 cfm has a friction loss of. = (0.109136 * 156 1.9 ) / (2 5.02) = 1.97603 inches. = (0.109136 * 156 1.9 ) / (2 5.02 )* (4/100) = 49.40069 inches / 100 feet. Air Ducts are passages for air to travel within your home. The loss in pressure of the flow that occurs due to the air ...An Air duct pressure drop calculation is essential for designing and operating HVAC (Heating, Ventilation, and Air Conditioning) systems. Understanding how to calculate pressure drops in air ducts allows mechanical engineers to design more efficient and effective systems, ensuring optimal airflow and comfort in residential and commercial …A simple volume unit converter to convert air flow volumes from ... Calculate the equivalent size of spiral ducting when you have only been given the rectangular duct dimension (it works the other way also) Open the ES Calculator. System Pressure Calculator. The System Pressure Calculator helps you work out the resistance in pascals that ...The friction loss in a 20 inches duct with air flow 4000 cfm can be estimated to approximately 0.23 inches water per 100 feet duct as shown in the diagram above. The air velocity can be estimated to approximately 1850 feet per minute. A major friction loss diagram for air ducts - Imperial units ranging <i>10 - 100 000 cfm</i>. FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. HVAC Charts - Your Source for Heating & Air Conditioning Charts and Supplies. Duct Sizing Calculator. The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct ...The average per-square-foot cost for duct cleaning is $0.20 to $0.40. Using this standard, a 1,200-square-foot house could run from $240 to $500, while a 3,000-square-foot one could range from $600 to $1,200. When pricing this way, cleaners usually include registers and the insides of the ducts themselves, along with the air handler and …The equivalent diameter is the diameter of a circular duct or pipe that gives the same pressure loss as an equivalent rectangular duct or pipe.. The table below can be used to compare equivalent diameters for rectangular and round circular ducts. The table is based on the ducts friction loss formula.. The rectangular dimensions and the air flow volume …A good HVAC duct sizing rule of thumb is to measure rooms in your home, the necessary airflow rates, and friction loss rate. Using these numbers you can calculate the appropriate HVAC duct size. For example, a one-to AC system typically uses 10-inch ducts, while a 4-ton AC system requires 18-inch ducts. There are several variables to …Calculation Method. Static Pressure Loss [inW/100ft] Air Flow [CFM] 3000 FPM. Round Duct Air Velocity. Infinity FPM. Rectangular Duct Air Velocity. 0.00049 Absolute Roughness [Foot] 14.42.ρ = 999.7 kg/m³. Find the dynamic viscosity: µ = 0.001308 kg/ (m · s) Compute the product of the density of water, the velocity of the flow, and L: ρ × u × L = 249.925 (m · s)/kg. Divide the result by the dynamic viscosity to find the Reynolds number: ReD = 249.925/0.001308 = 191,074 The flow is likely turbulent. QUICK-GUIDE. Select the duct material from the drop-down list (most duct sizing tools are typically based on galvanised steel ducting by default) Enter the air flowrate in cubic feet per minute (CFM) Enter an internal duct size in inches (this must be limited to a maximum aspect ratio of 5:1 for the results to be valid) The resulting velocity ... Duct Size Chart. Do your own calculations and compare them to our chart – or use the chart for quick, accurate calculations for duct size based on CFM needed for a room. One size is given for round ducts, its diameter. You have two or three options for rectangular ducts that give you the same or nearly the same square footage per duct.Best prices guaranteed. We match other Aussie retailers*. Use our sizing calculator below to determine the minimum size required for your room or house. Remember for ducted systems only include the air conditioned spaces, exclude areas like … Rectangular duct is rounded up to the nearest 1/4 inch. Calculations are for 60°F dry air at sea level, from 5 to 3000 cfm (approximately standard air which is 0.075lb da /ft³). If "ASHRAE 2013" is selected, Flexible roughness is 0.003 ft when straight and fully stretched tight at 0% compression (adjusted at other compressions), otherwise the ... Air Ducts - Cross Sectional Areas; Example - Generated Noise in Duct by Air Flow. The cross section area of a 200 mm duct can be calculated as. A = π ((0.2 m) / 2) 2) = 0.0314 m 2 The noise generated in the duct with an air flow velocity 10 m/s can be calculated as. L N = 10 + 50 log (10 m/s) + 10 log (0.0314 m 2) = 45 db The noise generated in the same …The pressure losses in ducts are caused by friction between the air and the duct surfaces, as well as by fittings and bends in the duct system. How do you calculate CFM from pressure drop? CFM (Cubic Feet per Minute) can be calculated from pressure drop using the fan laws, which relate CFM, pressure, and fan performance.Now, to properly calculate the return grille size, we have to make these two assumptions: Face velocity is 500 FPM (feet per minute). This is the speed at which the return grille sucks the air from your house into your ducts. Free grille area is 70%. As we know, the grille is always bigger than the duct through which the airflow flows.Dec 3, 2023 · The Duct Pressure Loss Calculator is an essential tool used to estimate the pressure drop or loss that occurs within a duct system due to various factors such as friction, length, diameter, velocity of airflow, and gravity. Its primary function is to calculate the pressure loss (ΔP) occurring in the duct, offering insights into the system’s ... Download duct static pressure calculator excel sheet XLS. Free spreadsheet program for air duct friction loss calculation. Download Free MEP Calculation Excel Sheets, AutoCAD Drawings, and Training Courses for HVAC, Firefighting, Plumbing and Electrical Systems Design.Duct-U-Lator. This app works as a Ductulator and Pressure Loss (friction) calculator which has the following functions. Converts Duct Shape or Size to Another. Determines Sizes for a Given Friction Rate. Determines Sizes for a Given Velocity. Determines Sizes for a Given Velocity and a Friction Loss Rate (simultaneous output)Example of big metal round and rectangular ducts (3,000+ CFM airflow). To figure out exactly how big ducts you need for central air conditioning systems, we have prepared complete CFM duct charts for all different kinds of ducts:. Duct sizing chart for flex ducts (round ducts with 5-20 inch diameter).; Duct sizing chart for metal ducts (round ducts …Air Duct Calculator. Double-sided. Side 1 = standard ducloator with calculations for both round and rectangular duct. Side 2 = Continental vs competitive cross reference for some common GRDs and a Grille sizing chart. Qty 25/package.Enter the air flowrate in litres/second (can change to cubic metres/second by use of drop-down to the right of the input) Enter an internal duct diameter (this can be any number, it doesn’t need to be standard duct size) To get an idea of the equivalent rectangular duct size, adjust the aspect ratio. Note that only aspect ratio up to 5:1 are ...The equal friction method for sizing air ducts is often preferred because it is quite easy to use. The method can be summarized to. Compute the necessary air volume flow (m 3 /s, cfm) in every room and branch of the system; Use 1) to compute the total air volume (m 3 /s, cfm) in the main system; Determine the maximum acceptable airflow velocity in the …Ductulator - Duct Diameter Calculator. Enter the required volume & velocity to see the necessary duct diameter. Required Air Volume. m³/sec m³/hr. Required Air Velocity. m/sec. Duct Diameter. mm. Health and Safety Executive recommended minimum duct …Return air duct size for 1-5 ton ACs is 14” to 22” for round ducts and 13”x12” to 32”x12” for rectangular ducts. Use the return air duct size calculator below for accurate dimensions required for your air conditioner or heat pump. There is also a table of return air duct sizes for round and rectangular ducts for ACs from 1.5 to 5 tons.Instructions. (Input information may generally be be obtained from design documents or field measurements) Line 1. Enter the temperature of the air entering the duct. Line 2. Enter the ambient temperature (the average temperature of the air surrounding the duct) Line 3. Enter the flow rate of the air carried by the duct in cubic …Ordinary heating, ventilating, and air conditioning duct systems read air pressures at 0.4 psi or less, often much less. 1 psi equals 27.7 inches of water gauge; 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. Duct Pressure: Duct system is pressurized by three pressures: •Imperial Equation. Determine the following formula, which can be used to calculate the air duct velocity: V = 0.408 Q/D 2. Components. = Air velocity inside the duct (feet/s) = Air … Air Duct Calculator. Double-sided. Side 1 = standard ducloator with calculations for both round and rectangular duct. Side 2 = Continental vs competitive cross reference for some common GRDs and a Grille sizing chart. Qty 25/package. Cleaning helps not only remove them, but may also remove blockages that can help make your system run more efficiently. Keep reading to learn more about the cost of duct cleaning services. 2024 Duct Cleaning Costs. Calculate local project costs by entering your zip code. Typical Price Range. $ 450 - $ 1,000.While air duct cleaning and repair lengthens its life span, ductwork typically needs major replacement every 15 years to work properly. The national average cost for full ductwork replacement is $1,450–$8,000; however, the cost can range anywhere from $250–$12,000 depending on home size, system accessibility, and materials used.Perfect for one time or a limited number of HVAC projects. Includes residential load calculator, plus duct sizing, equipment selection and cost analysis software for one low price This software includes all the features and capabilities of the permanent version, however it will expire on your computer 60 days after purchase. Only $49.Air Flow Conversion Calculator. CUI Devices' air flow conversion calculator can be used to convert between common units for volume air flow and air velocity flowing past a point in a specified area of duct. To use the calculator, enter your air velocity or volume air flow and duct area/type, select your units, click calculate air flow, and your ...1. Diameter converter, which converts circular diameters to equivalent rectangular ducts. 2. Ventilation parameter calculator allows the diameter, air speed, airflow and dynamic pressure of your installation to be calculated. 3. Pressure drop calculation tool for installations with straight sections and duct system elements. 4.Undersized return air ducts result in the ducts and grills being more noisy than usual and the air conditioner components becoming stressed, thus reducing the lifetime of the unit. Use our handy return air duct size calculator or charts below to help you determine the correct return air vent size for your home.Calculate velocities in circular and rectangular ducts - imperial and SI-units - online calculator. Ducts or Pipes through Steel Joists - Maximum Sizes. Maximum sizes of …Feb 16, 2023 · Calculate for each individual room. To calculate CFM, you need to know the size of your heating or cooling unit in tons. Multiply this number by 400, which is the average output of an HVAC unit. Then divide by the total square footage of your home. This will give you the multiplier for all your rooms’ CFM. The chart below can be used to estimate velocities in air ducts. The default values are for air flow 400 cfm (680 m3 /h) , duct size 8 in (200 mm) and velocity 1150 fpm (5.8 m/s) . Download and print Air Ducts - Velocity …Duct CFM @ .08 supply .05 return. This calculator does not replace good ACCA manual D or SMACNA principles. It does however provide basic duct sizes and CFMs based on these principles. This calculator can be used to estimate CFM or duct size using round Metal or Flexible "properly installed" typical duct runs. Duct Size Calculator. Ductulator is an engineering tool to calculate air duct dimensions based on given inputs including air-flow, duct material roughness and either air pressure static loss (friction method) or air velocity (velocity method). This online ductulator calculates the dimensions for both round and rectangular duct options (one ... The average cost to replace ductwork is $1,400 to $5,600, depending on the home's size. Air duct replacement costs $25 to $55 per linear foot or $270 to $500 per duct for a crawl space, attic, or basement. New ductwork installation costs $2,400 to $6,600 for a house without HVAC ducts. Cost to replace ductwork by house size - chart. Head loss or major loss in air ducts - equations and online calculator for rectangular and circular ducts - Imperial and SI units. The major loss, or friction loss, in a circular duct in galvanized steel with turbulent flow can for imperial units be expressed. Δh = 0.109136 q 1.9 / d e 5.02 (1) where. Δh = friction or head loss (inches water ... Formula. The formula for air duct sizing involves the calculation of air velocity (V) and duct cross-sectional area (A) to determine the air volume flow rate (Q), expressed in cubic feet per minute (CFM). Q = A × V. This equation comes from the principle of continuity in fluid mechanics which states that for incompressible flow, the product of ... To calculate allowable leakage, you must know the system surface area, the required test pressure and the specified leakage class. System (or section) Surface Area. sq.ft. Test Pressure. (in.wg.) SMACNA Leakage Class*. Allowable leakage based on your input is: cfm. *SMACNA recommends using leakage classes in table below when the designer …While air duct cleaning and repair lengthens its life span, ductwork typically needs major replacement every 15 years to work properly. The national average cost for full ductwork replacement is $1,450–$8,000; however, the cost can range anywhere from $250–$12,000 depending on home size, system accessibility, and materials used.Cleaning helps not only remove them, but may also remove blockages that can help make your system run more efficiently. Keep reading to learn more about the cost of duct cleaning services. 2024 Duct Cleaning Costs. Calculate local project costs by entering your zip code. Typical Price Range. $ 450 - $ 1,000.This calculator allows for calculating the mixed air temperature of a third air source. An example of a third air stream is a Bypass air duct that goes from the supply air plenum back to the return air plenum. Trane has an excellent Engineers Newsletter describing Dehumidify with Constant-Volume Systems. Free HVAC Duct Sizing - in SI/Metric or US/Imperial units. Welcome to CalcuDUCT - the quick and easy way to size ducts for any HVAC application. The chart below can be used to estimate velocities in air ducts. The default values are for air flow 400 cfm (680 m3 /h) , duct size 8 in (200 mm) and velocity 1150 fpm (5.8 m/s) . Download and print Air Ducts - Velocity …The kinematic viscosity of air is determined by the properties of air, just like the density of air. However, both values are based on a set air condition. In the case of duct static pressure calculation, the properties of air are set at 1 atmospheric pressure at 20°C. Friction Loss Factor, f. The friction factor (f) is calculated using the ... Adjustable Absolute Duct Roughness. If selected, Flexible roughness is 0.003 ft when. straight and fully stretched tight at 0% compression. (adjusted at other compressions), otherwise the. original method of constant 0.01 ft roughness is used. Use ASH RAE 2013 Flex Compression. Ductulator - Hand held rotating calculator used for sizing supply and return duct systems using the equal friction design method. Includes scales for friction loss per unit length, air volume, air velocity, round duct diameter, and rectangular duct diameters. One side uses English units, the other side uses Metric units. Duct Sizing Calculator. The duct sizing calculation involves determining the proper ductwork size needed for an HVAC system. The formula used in this calculation is Q=VA, where Q is the airflow rate, V is the air velocity, and A is the area of the duct.Knowledge is power, so although we can't always correct the problems we see with duct work, I'm hoping that with some knowledge we can make some little chang...October 9, 2023 by GEGCalculators. The size of a return air duct should generally be based on the HVAC system’s capacity. A common rule of thumb is to aim for approximately 400-450 CFM (cubic feet per minute) of airflow per ton of HVAC capacity. For example, a 2-ton system might require a return duct with a size of around 16 inches in diameter.QUICK-GUIDE. Select the duct material from the drop-down list (most duct sizing tools are typically based on galvanised steel ducting by default) Enter the air flowrate in litres/second (can change to cubic metres/second by …Duct Sizing Calculator. The duct sizing calculation involves determining the proper ductwork size needed for an HVAC system. The formula used in this calculation is Q=VA, where Q is the airflow rate, V is the air velocity, and A is the area of the duct.Minor or Dynamic losses in duct systems are pressure losses caused by. Minor or dynamic pressure loss in air duct system components can be expressed as. Δpminor_loss = ξ ρ v2 / 2 (1) where. ξ = minor loss coefficient. Δpminor_loss = minor pressure loss (Pa (N/m2), psf (lb/ft2)) ρ = density of air (1.2 kg/m3, 2.336 10-3 slugs /ft3)Air duct pressure loss. Friction loss calculation is made in rectangular or round ventilation ducts. Fill in the form below. Unit system. : Duct type. : Duct position.mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load. Rectangular duct is rounded up to the nearest 1/4 inch. Calculations are for 60°F dry air at sea level, from 5 to 3000 cfm (approximately standard air which is 0.075lb da /ft³). If "ASHRAE 2013" is selected, Flexible roughness is 0.003 ft when straight and fully stretched tight at 0% compression (adjusted at other compressions), otherwise the ... This calculation Excel program makes it possible to carry out the calculation of the pressure losses on the duct works and air distribution systems. Download Duct Friction Loss Excel Calculator: Fan static head is calculated according to the duct friction loss. the more the value of friction loss is the more the static head of …
Air Duct Calculator. Double-sided. Side 1 = standard ducloator with calculations for both round and rectangular duct. Side 2 = Continental vs competitive cross reference for some common GRDs and a Grille sizing chart. Qty 25/package.. Night swim where to watch
A duct size calculator, commonly known as a ductulator, depends on factors like the size of the space you’re heating or cooling, air flow …Duct Calculator - CDI Curbs. Air Duct Calculator. Flexible Duct Friction Loss Calculator. 1. Enter Friction Loss Per 100' of duct (inches of water), Duct Airflow (CFM), Duct Length …This article provides information on how to use the Ductwork Calculator for air flow CFM, friction loss and velocity. It explains the process of duct sizing diameter with accurate results when the right information is plugged into it. The article also gives a detailed explanation of each step in the process and what data … See moreHVAC Charts - Your Source for Heating & Air Conditioning Charts and Supplies. Duct Sizing Calculator. The Duct Sizing Calculator is a hand held sliding calculator used for sizing supply and return duct systems using the equal friction, or velocity reduction design method. Front of calculator includes scales for friction, velocity, round duct ...To adequately calculate the speed of air in ducts, we have to primarily calculate the cross-section of the duct. Shape-wise, ducts can be: Round. The area of round flex ducts is calculated as π*R 2 where R is the radius of the duct. Example: 10-inch round duct has a radius of 5 inches.V = 0.408 Q/D 2. Components. = Air velocity inside the duct (feet/s) = Air flow rate inside the duct (GPM) = Air flow rate inside the duct (inches) Metric Equation. Determine the following formula, which can be used to calculate the air duct velocity: V …Duct calculator. Air and liquid duct; Calculate duct flow resistance, environmental heat exchange, and adiabatic; Note: outer coefficient of heat transfer usually is 3~10, >10 when winds. Download & Buy. For windows, without network and browser limits. FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. Formula. The formula for air duct sizing involves the calculation of air velocity (V) and duct cross-sectional area (A) to determine the air volume flow rate (Q), expressed in cubic feet per minute (CFM). Q = A × V. This equation comes from the principle of continuity in fluid mechanics which states that for incompressible flow, the product of ... The ASHRAE Duct Fitting Database (DFDB) app allows you to perform pressure loss calculations for all 200+ ASHRAE duct fittings in both I-P and SI units. Use this mobile app in the field for quick duct pressure loss calculations. The inputs can be adjusted by touch, and installation is automatic. Available via iTunes®, the app is now universal ...50°F (27.8°C) 2″ (50mm) Recommended Duct Insulation Thickness for Concealed Ducts. So, if my dew point is 77°F (25°C) and the supply air temperature is 59°F (15°C), the temperature difference is 18°F (10°C) which is below 30°F (16.7°C). Therefore, my duct insulation should be 1″ (25mm) thick. Purchase ADI Ductulator. The ADI - Air Distribution Institute, was formed in 1947 to promote the use of fabricated steel duct pipe and fittings for air distribution products. Today the alliance of ADI member companies produce steel duct pipe and fittings designed to efficiently deliver conditioned air in your home and office. .