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 …These calculations are divided in four areas: 1. Diameter converter, which allows converting circular to equivalent rectangular ducts. 2. Calculator of different ventilation parameters, with which will be able to obtain the diameter, the air speed, the airflow and the dynamic pressure of your installation. 3.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. …Volume is the cross-sectional area multiplied by the length of the duct.; Density is the density of the material the duct is made of.; Diameter is the diameter of the round or spiral duct.; Width and Height are the dimensions of rectangular, oval, or flat oval ducts.; Length is the length of the duct.; For insulated ducts, you calculate the weight …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. 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 …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... The velocity of an air duct with area 16 sq.ft and air flow of 10 CFM would be : V = 10 / 16 = 0.625 FPM. When converted to FPS, it is 0.0104 FPS. Air duct also termed as ductulator is a passage that is used to provide fresh air into rooms, buildings etc., Air ducts may be in circular, square and in rectangular shapes. 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.A duct calculator is a tool used to determine the correct size of ducts in an HVAC system. How do I use a duct calculator? You’ll need to know the air volume flow rate, the velocity …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 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.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 DuctsExample 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 …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 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.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 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 efficiency.AllDuctCalc™ - HVAC Air Duct Calculator v2 Updated 10/26/15: Provide inputs in the blue boxes, other inputs optional. 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. AllDuctCalc™ - HVAC Air Duct Calculator v2 Updated 10/26/15: Provide inputs in the blue boxes, other inputs optional. 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 ... 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 ...Volume is the cross-sectional area multiplied by the length of the duct.; Density is the density of the material the duct is made of.; Diameter is the diameter of the round or spiral duct.; Width and Height are the dimensions of rectangular, oval, or flat oval ducts.; Length is the length of the duct.; For insulated ducts, you calculate the weight …Nov 11, 2023 · The Duct Area Calculator is a powerful tool designed to help individuals and professionals in the HVAC industry determine the cross-sectional area of rectangular and circular ducts. This essential calculation aids in optimizing airflow, ensuring efficient ventilation systems, and maintaining optimal indoor air quality. 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 …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.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 ... 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. 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 …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 …Example 2.5 ton Duct System Diagram. Sizing for a 2.5 Ton unit, we start with a 16" supply at 875 CFM -1125 CFM. We then take a 7" and 5" run (-200 CFM) off of this section bringing the remaining total to 675 CFM - 925 CFM. A drop from 16" to 14" in now required to keep pressure and velocity up.The smallest return air grille is usually starts at 4 inches by 4 inches. So, the next corresponding return air grille size includes 4×6, 6×6, 6×4, 8×6, 4×8 and so on. The largest return air grille is typically stops at 48 inches by 24 inches. Here are some examples of a standard return air grille: 4×4. 6×6.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.Kurb Air Duct Calculator. ductulator.app. Calculation Method. Static Pressure Loss [inW/100ft] Air Flow [CFM] 3000 FPM. Round Duct Air Velocity. Infinity FPM. … 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. 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...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 ...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 …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.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 …Dec 20, 2016 · 20 Dec 2016; Atlanta; New Duct Sizing Calculator Available. Media Contact: Allen Haynes 404.446.1677 [email protected]. ATLANTA (Dec. 20, 2016) – A new duct sizing calculator from ASHRAE and the Air Distribution Institute (ADI) allows HVAC air distribution system designers to more accurately size ducts, especially flex ducts under varying amounts of compression, based on research results. 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.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 ...Section 5 - Air Distribution System Design This section provides an executive overview of duct system design procedures, additionally covering the use of a branch take off fitting at the end of a supply air trunk duct. Section 6 - Duct Sizing Calculations This section covers the duct system design procedures in detail.About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright ...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... 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. 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.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 ...Using the chart, you’ll see that for a 12” round flex duct, maximum CFM is 480 CFM or 500 CFM depending on the friction rate. Duct size for 115 CFM. Find the CFM closest to 115 in the table above. It will be found in different columns depending on the friction rate. If there isn’t an exact match, go up to the duct size.The Duct Area Calculator is a powerful tool designed to help individuals and professionals in the HVAC industry determine the cross-sectional area of rectangular and circular ducts. This essential calculation aids in optimizing airflow, ensuring efficient ventilation systems, and maintaining optimal indoor air quality. 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. 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. 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.How Much Does an HVAC Replacement Cost in 2024? Average Cost Range: $6,465 - $11,877. Use the calculator below for a more accurate local estimate. Use Modernize's 2024 cost calculator to get accurate HVAC replacement cost. Get local price ranges by zipcode for cooling, heating or both!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 more FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. 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 ...VariTrane Duct Designer streamlines duct design and improves calculation precision, letting you optimize your designs while obtaining a minimum pressure system. VariTrane Duct Designer enables you to organize the layout structure of your duct system and provides detailed engineering information on a section-by-section …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 ... 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.Apr 25, 2022 · At 350-400 CFM per 12,000 BTUs of heating capacity, there’s enough airflow to circulate heated air through supply ducts and pull cool air back to the furnace or air handler through the cold air returns. A 3-ton unit, or 36,000 BTUs, would need a blower capable of moving 3 x 350-400 CFM, so a total of 1,050 to 1,200 CFM. 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 …Air Duct Calculator. KALK.PRO's duct calculator will help you estimate the required duct size of the ventilation system for quality air exchange …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 … The velocity of an air duct with area 16 sq.ft and air flow of 10 CFM would be : V = 10 / 16 = 0.625 FPM. When converted to FPS, it is 0.0104 FPS. Air duct also termed as ductulator is a passage that is used to provide fresh air into rooms, buildings etc., Air ducts may be in circular, square and in rectangular shapes. Volume is the cross-sectional area multiplied by the length of the duct.; Density is the density of the material the duct is made of.; Diameter is the diameter of the round or spiral duct.; Width and Height are the dimensions of rectangular, oval, or flat oval ducts.; Length is the length of the duct.; For insulated ducts, you calculate the weight …FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. 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. The smallest return air grille is usually starts at 4 inches by 4 inches. So, the next corresponding return air grille size includes 4×6, 6×6, 6×4, 8×6, 4×8 and so on. The largest return air grille is typically stops at 48 inches by 24 inches. Here are some examples of a standard return air grille: 4×4. 6×6.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 …The Duct Area Calculator is a powerful tool designed to help individuals and professionals in the HVAC industry determine the cross-sectional area of rectangular and circular ducts. This essential calculation aids in optimizing airflow, ensuring efficient ventilation systems, and maintaining optimal indoor air quality. Sheet Metal Duct Friction Loss Calculator. 1. Enter Duct Airflow (CFM), Duct Velocity (FPM), Duct Length and the number of bends. 2. Read Round Duct Diameter (inches) and Friction Loss Per 100' of duct (inches of water). 1. Enter Friction Loss Per 100' of duct (inches of water), Duct Airflow (CFM), Duct Length and the number of bends. 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. 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 …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 …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 ...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.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 ... A major friction loss diagram for air ducts - SI units. Air Ducts - Friction Loss Diagram A major friction loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm. Air Ducts - Velocity Diagram Air flow volume, duct size, velocity and dynamic pressure. Circular Ducts - Dimensions Standard size of circular ventilation air ducts. Duct ... The Duct Size Calculator is a quick reference tool for approximating duct size and equivalent sizes of sheet-metal duct and flexible duct. A new duct-sizing calculator from ASHRAE and the Air Distribution Institute (ADI) allows HVAC air-distribution-system designers to size ducts more accurately, especially flex ducts under …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) 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 … 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. How to design a duct system. In this video we'll be learning how to size and design a ductwork for efficiency. Includes a full worked example as well as usin...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)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.Quickly find the duct diameter best suited to your needs, based on the desired air flow rate and the air velocity in the network. The tool will give you the diameter best suited to your …
Duct thickness. Refers to the thickness of the goods on the actual duct. Duct density. Refers to the density of the material from which the duct is made. Duct weight. Refers to the weight of the current duct per meter. Media density. Refers to the density of the medium flowing through the actual duct. Set to air in the initial position. Media .... Concentration games
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 ... 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 work attenuation. Calculate the attenuation in unlined and lined ducts. Note that the table and diagrams list the attenuation in dB/m. 13. ... The speed and attenuation of sound in moist air varies with sound frequency and air humidity. Sound Attenuation - …Kurb Air Duct Calculator. ductulator.app. Calculation Method. Static Pressure Loss [inW/100ft] Air Flow [CFM] 3000 FPM. Round Duct Air Velocity. Infinity FPM. …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 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.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 ...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 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.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. 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: 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 ... 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. Using the chart, you’ll see that for a 12” round flex duct, maximum CFM is 480 CFM or 500 CFM depending on the friction rate. Duct size for 115 CFM. Find the CFM closest to 115 in the table above. It will be found in different columns depending on the friction rate. If there isn’t an exact match, go up to the duct size.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 ...mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load.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.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.FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts..