For 1000 CFM, we need 1650.12 FPM to 11,459.16 FPM, if we use 4-10 inch round ducts. This is quite an enormous air velocity (11,459.16 FPM is equal to 130 miles per hour (mph)). Now, let’s have a look at the 2nd part for rectangular air ducts, starting with the 2nd calculator: For 1000 CFM, we need 1650.12 FPM to 11,459.16 FPM, if we use 4-10 inch round ducts. This is quite an enormous air velocity (11,459.16 FPM is equal to 130 miles per hour (mph)). Now, let’s have a look at the 2nd part for rectangular air ducts, starting with the 2nd calculator: 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)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 …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.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. The Digitized Ductulator is a free online calculator for sizing HVAC ducts. Use it in one of two ways; either enter the duct size to find the equivalent CFM, or input the CFM to find the right size of rectangular, round or flex duct. Click here to use the Ductulator. Use the right size duct. Duct that's too big, or too small can cause problems ... Get free shipping on qualified Ducting & Venting products or Buy Online Pick Up in Store today in the ... resistant, 4-ply aluminum foil laminate that encapsulates a high density, corrosion resistant wire helix. This forms an air tight and easy to use air duct. View Product. Explore More on homedepot.com. Doors & Windows. 1 Panel 36 x 79 ...By knowing how to calculate static pressure in air duct systems, you can determine that the right push of air counteracts the resistance in airflow. In a static pressure calculation, we are looking for the push of air to exceed the resistance. Otherwise, the system won't be able to circulate air throughout the 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.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 Engineering ToolBox (2004). Air Duct Calculator. [online] Available at: https://www.engineeringtoolbox.com/air-duct-calculator-d_813.html [Accessed Day …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 …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.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...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 …These calculators estimate the temperature drop (or rise) of air flowing in a duct or fluid flowing in a pipe. An example is the use of insulation to minimize temperature change (either temperature drop or rise) of a process fluid from one location to another(e.g. a hot fluid flowing down a pipe). Temperature Drop Calculator for Air DuctsFormula. 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 ... 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. The Ductulator - Duct Sizing Calculator is a hand held rotating calculator used for sizing supply and return duct systems using the equal friction design method. This accurate, easy-to-use duct size calculator includes scales for friction loss per unit length, air volume, air velocity, round duct diameter and rectangular duct diameters.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.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.September 17, 2023 by GEGCalculators. Converting round to rectangular duct sizes depends on specific design factors. As a rough approximation, a round duct with a diameter of 6 inches might correspond to a rectangular duct of 8×4 inches, but these conversions vary based on project requirements. Precise calculations should be made using HVAC ...Enter the air volume in CFM [l/s]. Select an input criteria and enter its value. Optional: Enter a constraining rectangular duct dimension in inches [cm] Click the Calculate button. …Friction Loss per 100 Feet = (0.109136 * q 1.9 ) / (d 5.02 )* (l/100) Where, q = Air Volume Flow. d = Equivalent Duct Diameter. l = Duct Length. Online air duct friction loss calculation. Use this simple science air duct friction loss calculator to …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 ...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.Air Duct Calculator/Ductulator with Sleeve. 4.2 out of 5 stars. 18. $15.60 $ 15. 60. FREE delivery Apr 29 - May 2 . Add to cart-Remove. Trane Ductulator and Charging Calculator Kit - Trane Flex Ductulator with Sleeve, Metal Ductulator, R-22 Charging Calculator, R410A Charging Calculator. 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 ... Aug 21, 2023 · 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. Download HVAC Duct Quantities, Weight and Area Calculation Sheets. Air Duct quantity can be estimated in sq. meters or kilograms. These excel sheets will enable you to calculate or estimate the duct weight or the duct surface area.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 ...September 17, 2023 by GEGCalculators. Converting round to rectangular duct sizes depends on specific design factors. As a rough approximation, a round duct with a diameter of 6 inches might correspond to a rectangular duct of 8×4 inches, but these conversions vary based on project requirements. Precise calculations should be made using HVAC ...Download HVAC Duct Quantities, Weight and Area Calculation Sheets. Air Duct quantity can be estimated in sq. meters or kilograms. These excel sheets will enable you to calculate or estimate the duct weight or the duct surface area.Similar Apps to Air Duct Calculator IWA 42 006. The Air Duct Calculator App shows a slide chart that affords the configuration of rectangular, circular and oval air ducts in a minimum of time ...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.So, the duct design work is made simpler and easy. Since this is a web-based program, users can log in from any browser using an ID and password. Apart from duct designing, this software also helps in Duct sizing. With DuctQuote, you can. Calculate air flow for duct design; Draws 3D systems; Generate custom quotes using logo and … 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 = 1.274 Q/D 2. Components. Purpose and Learning Objectives. The purpose of this presentation is to introduce new and optimized techniques for designing high performing VAV systems at minimal cost. At the end of this presentation, you will be able to: Size VAV duct mains cost effectively. Select VAV boxes for minimum life cycle cost.Duct Sizer ( Ductulator) for HVAC air ducts. It is designed for calculating and sizing duct dimensions according to air volume CFM, roughness, velocity, etc. It is available in SI and British IP units. Duct sizing needs a ductulator or software but this excel calculator performs the same calculations.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.Highlights. Your air ducts deliver cool and hot air throughout your home. There are sheet metal, fiberglass-lined, fiberboard, and flexible ducts. Some signs you need a cleaning include dirty vents and a pest infestation. Air duct cleaning costs $380 on average and ranges between $270 to $490.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>.Duct and vent cleaning costs $25 to $45 per vent or $0.15 to $0.25 per square foot. Air duct sanitizing costs $70 to $150 more to prevent mold growth. An air duct inspection costs $80 to $180. Cleaning the HVAC system costs $60 to $370 more for a furnace or AC unit. Air duct cleaning cost - chart.At А+ AIR SERVICES Cleaning, our excellent customer service has earned us loyal customers throughout our 20 years in business. With a wide range of services, we are experienced at mold remediation, ductwork installation, cleaning kitchen exhaust systems, air ducts, dryer vent and chimney, as well as taking on corporate and commercial …By multiplying air velocity by the cross section area of a duct, you can determine the air volume flowing past a point in the duct per unit of time. Volume flow is usually measured …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 ...All Duct Calculator. An inclusive air duct calculator for diameter, velocity, CFM, and pressure drop of various types of duct. It will also determine round duct equivalents for rectangle, flat oval, and elliptical (flattened round) duct. Duct roughness and air properties are adjustable and includes a metric option. Open Calculator.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.The velocity reduction method can be used when sizing air ducts. Equivalent Diameter - Rectangular vs. Circular HVAC Ducts Rectangular equivalent diameter for air flows between 100 - 50000 cfm. Fluid Flow - Equivalent Diameter Convert rectangular and oval duct geometry to a equivalent circular diameter - online calculator with imperial and SI ...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. Ducting Calculators and Air Volume Converter. Nordfab can offer technical assistance with determining whether our ducting is best for your application and with designing duct installations. Please contact us with your requirements. Input CFM Input Velocity (FPM) Ideal Round Duct Diameter Duct Friction in Straight Duct. Calculate. The cross-sectional area of the duct is: Then the mass flow rate of air through the duct and the rate of heat loss become. therefore, or 5688 kJ/h. The cost of this heat loss to the home owner is. Conversion: 1 Therm = 105,480 kJ. Conclusion: The heat loss from the heating ducts in the basement is costing the home owner 4 cents per hour.FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts.Diameter of Air Duct Sizing =√ ( (576 × 8) / (3.14 × 15)) = 9.8911 inch. Online ducting calculator to find the diameter of duct size. Sizing of air duct can be done using Velocity Method, Constant Pressure Loss Method and Static Pressure Recovery Method.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 …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 …Jan 14, 2012 · 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 ... 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. 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 Engineering ToolBox (2004). Air Duct Calculator. [online] Available at: https://www.engineeringtoolbox.com/air-duct-calculator-d_813.html [Accessed Day …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.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 …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 …Ducting Calculators and Air Volume Converter. Nordfab can offer technical assistance with determining whether our ducting is best for your application and with designing duct installations. Please contact us with your requirements. Input CFM Input Velocity (FPM) Ideal Round Duct Diameter Duct Friction in Straight Duct. Calculate. 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 = 1.274 Q/D 2. Components. Air Duct Calculator. KALK.PRO's duct calculator will help you estimate the required duct size of the ventilation system for quality air exchange …The circuit of the cold air ducts is calculated for 100% of the necessary flow. On the other hand, for the hot air ducts, one admits 50% to 75% of the cold air flow according to thermal loads. The variation between the temperature of the buildings in summer and the air in the cold air duct is 50 to 55.5 °F (10 to 13°C). For 1000 CFM, we need 1650.12 FPM to 11,459.16 FPM, if we use 4-10 inch round ducts. This is quite an enormous air velocity (11,459.16 FPM is equal to 130 miles per hour (mph)). Now, let’s have a look at the 2nd part for rectangular air ducts, starting with the 2nd calculator: Mar 25, 2024 · The ductulator calculator is a specialized tool used in the HVAC industry to determine the most efficient duct sizes for air distribution within a space. It helps calculate the perfect balance between duct size, air velocity, and airflow, ensuring the HVAC system operates at peak efficiency. This balance is crucial for maintaining comfortable ... 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: •By knowing how to calculate static pressure in air duct systems, you can determine that the right push of air counteracts the resistance in airflow. In a static pressure calculation, we are looking for the push of air to exceed the resistance. Otherwise, the system won't be able to circulate air throughout the ducts.Similar Apps to Air Duct Calculator IWA 42 006. The Air Duct Calculator App shows a slide chart that affords the configuration of rectangular, circular and oval air ducts in a minimum of time ...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 ...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 …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 ...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.The velocity reduction method can be used when sizing air ducts. Equivalent Diameter - Rectangular vs. Circular HVAC Ducts Rectangular equivalent diameter for air flows between 100 - 50000 cfm. Fluid Flow - Equivalent Diameter Convert rectangular and oval duct geometry to a equivalent circular diameter - online calculator with imperial and SI ... 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. 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 …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 …Similar Apps to Air Duct Calculator IWA 42 006. The Air Duct Calculator App shows a slide chart that affords the configuration of rectangular, circular and oval air ducts in a minimum of time ...The air duct calculator, or “ductulator,” is a commonly used tool for designing and installing duct systems. Unfortunately, many designers and technicians receive limited instructions on its correct use. This lack of instruction frequently results in duct systems that fail to perform as intended. It’s typical to find that delivered airflow into …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 …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.The Ductulator - Duct Sizing Calculator is a 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 ...
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.. Canebrake country club
Precise Calculations: Learn special techniques for superior installation, calculating duct sizes and friction rate. Reduce Hot & Cold Spots: Master duct system balancing to minimize temperature fluctuations. *This class qualifies for 8 hours of NATE continuing education credits. Program Price: $399. Premier Dealers: $319* (20% discount)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 …Lindab Vent Tools app streamlines ventilation system calculations with practical tools for HVAC professionals. This handy app offers a collection of practical calculation tools for the HVAC industry, including duct dimensioning, pressure drop, airflow, and offset calculation for Lindab's products. The app also includes a k-factor calculator for versatile use …The Digitized Ductulator is a free online calculator for sizing HVAC ducts. Use it in one of two ways; either enter the duct size to find the equivalent CFM, or input the CFM to find the right size of rectangular, round or flex duct. Click here to use the Ductulator. Use the right size duct. Duct that's too big, or too small can cause problems ...By knowing how to calculate static pressure in air duct systems, you can determine that the right push of air counteracts the resistance in airflow. In a static pressure calculation, we are looking for the push of air to exceed the resistance. Otherwise, the system won't be able to circulate air throughout the 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.Check this out: air ducts - or HVAC ductwork, or AC ducts - are conduits that supply warm or cool air to heat, ventilate, and cool each room in a house. Air ducts are connected to the HVAC unit, which filters and heats / cools your home’s air before sending it off. Air ducts are a vital part of your HVAC system, providing thermal well-being ...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 ...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 -Slide Rule Style. This rectangular air duct calculator is the technicians favorite. Provides the following information with one setting:- Friction- Velocity- Round Duct Size- Surface Area...and more. Size: 4" x 8.5". ISBN No. 9781622709823Sturdy construction of heavyweight calculator board with 6 metal eyelets. 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. 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.The 922 velocity and air flow calculations are based on standard air at 29.92" hg at 70 °F. Tips. When we talk about positioning the pitot tube 10 straight duct diameters upstream and 3 straight duct diameters downstream of the tranverse plane, we need to first convert rectangular duct measurements into their equivalent circular diameters. 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) AllDuctCalc™ - HVAC Air Duct Calculator v2 Updated 10/26/15: Provide inputs in the blue boxes, other inputs optional.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 ….