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. …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.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. Example - Calculate Reynolds Number. A Newtonian fluid with a dynamic or absolute viscosity of 0.38 Ns/m 2 and a specific gravity of 0.91 flows through a 25 mm diameter pipe with a velocity of 2.6 m/s .. Density can be calculated from the specific gravity of the fluid and the density of the specific gravity reference water 1000 kg/m 3 - as. ρ = 0.91 (1000 …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.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.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 ...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 DuctsDec 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 ... The two most common insulated rigid ducts are supply air ducts and return air ducts used for air conditioning. Meanwhile, the fresh air ducts and exhaust air ducts in toilets and mechanical rooms can be uninsulated rigid ducts. In HVAC, main ducts and branch ducts are usually rigid ducts. They are more likely in a rectangular shape rather than ...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 …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.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. 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 ... Calculation of duct insulation. Easy program which, by entering a few values, immediately calculates the surface area of the ducts and insulation of the aeraulic circuit under consideration. Valid for quadrangular and circular ducts. In addition to the thickness of the insulation, it is possible to enter waste values (percentage of materials ...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.mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load.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 …The two most common insulated rigid ducts are supply air ducts and return air ducts used for air conditioning. Meanwhile, the fresh air ducts and exhaust air ducts in toilets and mechanical rooms can be uninsulated rigid ducts. In HVAC, main ducts and branch ducts are usually rigid ducts. They are more likely in a rectangular shape rather than ...Pull the airflow vertically to hit the friction loss line at 0.1 in.wg. Then, pull the line diagonally to the right and find the suitable duct diameter. 14″ round duct is less than ideal because the friction loss will be greater than 0.1 …DUCTULATOR. Sizing air ducts is essential task for HVAC Engineers, it requires quick tool to aid HVAC designer to determine air duct dimensions while drafting AC layouts. DUCTULATOR Software, uses two methods to size air ducts based on velocity or static regain method, taking into account the air properties at given temperature and elevation ...Updated March 25, 2024. Show Your Love: The ductulator calculator is a specialized tool used in the HVAC industry to determine the most efficient duct sizes for air distribution …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.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 …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 …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 ...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.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.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 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 ... 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 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 duct weight can be calculated using the following formula: DW = ( (2* (H+W)) L T)*D. Where the variables are: The duct density for aluminum is 0.1 lbs/in^3. To calculate duct weight, simply multiply the sum of the height and width by 2, multiply the result by the length and thickness, and then multiply the final product by the density.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. 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.Online Head Loss Calculator. The calculator below, which is based on eq. (2) , can be used to calculate the head loss in a duct, pipe or tube.The default values used in the calculator are for air flow 20 o C , 1.2 kg/m 3 and 6 m/s .The default density of water commonly used as reference fluid is 1000 kg/m 3.The friction coefficient is calculated … 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. 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!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 … Air Duct Calculators (Ductulator) 2/5. Watch on. This handy little device allows you to size your new air duct, and better understand what to expect from existing duct work. A Ductulator helps you properly size your ducts, estimate air loss, find the round or rectangular duct equivalent, and determine velocity. It can prevent some costly errors ... 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.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)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 … 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 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.DUCTULATOR. Sizing air ducts is essential task for HVAC Engineers, it requires quick tool to aid HVAC designer to determine air duct dimensions while drafting AC layouts. DUCTULATOR Software, uses two methods to size air ducts based on velocity or static regain method, taking into account the air properties at given temperature and elevation ... 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 ... CFM (10×12 Duct, 500 FPM) = 500 FPM × 10 Inches × 12 Inches / 144 = 416.67 CFM. We can see that the 10×12 duct generates 416.67 CFM of airflow at 500 FPM air speed. Now, we did a huge amount of calculations for these rectangular ducts at 1 FPM, 500 FPM, and 2000 FPM, and gathered all the results in this feet per minute to cubic feet per ...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.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.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.HVAC Ductwork Sizing Calculator. On this page: How to size your HVAC ductwork? Understanding measurement units for ducts. Using Modernize's HVAC and …mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load.The Ultimate HVAC Duct Calculator Guide: Increase Efficiency and Improve Airflow. HVAC duct calculators play an essential role in determining the proper size of ductwork for heating, ventilation, and air conditioning systems. Properly sized ducts are critical to maintaining optimum airflow, improving energy efficiency, and ensuring the …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.mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load.Sep 30, 2023 · Duct load calculation involves determining the heating or cooling load that a duct system must handle. It includes factors like air temperature, humidity, and the area being served. The calculation is complex and is typically done using specialized software. 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...Air Duct Calculator. KALK.PRO's duct calculator will help you estimate the required duct size of the ventilation system for quality air exchange … 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 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.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 ...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 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 …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 ...Now, we can use the previous equation to calculate the makeup air rate for kitchens and dryers under these conditions. (1) 400 – 190 = 210 CFM of makeup air (2) 200 – 190 = 10 CFM of makeup air. Makeup Air Duct Size. Below is a table of the average air inflow rates through different size ducts at different air pressures:DUCTULATOR. Sizing air ducts is essential task for HVAC Engineers, it requires quick tool to aid HVAC designer to determine air duct dimensions while drafting AC layouts. DUCTULATOR Software, uses two methods to size air ducts based on velocity or static regain method, taking into account the air properties at given temperature and elevation ...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. 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. 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 ...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. 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 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 …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 …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 - …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...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 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. 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 ... 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.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 ...
Duct Calculator Elite https://apps.apple.com/us/app/duct-calculator-elite/id665701601. Lift rides
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.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. 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 ... 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 ...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 ...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.Calculation of duct insulation. Easy program which, by entering a few values, immediately calculates the surface area of the ducts and insulation of the aeraulic circuit under consideration. Valid for quadrangular and circular ducts. In addition to the thickness of the insulation, it is possible to enter waste values (percentage of materials ...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. This online air duct calculator is used to calculate the velocity of air flow feet per minute (FPM), and feet per second (FPS) through any shaped (circle, square or rectangle) ductulator with …Jul 29, 2022 · 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. 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 …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! 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: mdot = Q / (cp x Δt) Calculate air mass flow rate from cooling load.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 : 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 …Enter 6" into the Duct Height (Optional) field. The results table show a 10"x6" duct. This calculator can also be used to simply convert round to rectangular or vice versa. It is unnecessary to consider the duct material, length, or air volume since it is just a physical, geometric calculation. Assume we have an 18" round duct.Step-3 Calculate Fresh Air Considering People outdoor air rate & Area area outdoor air rate as per ASHRAE 62.1: ... Normally, fresh air duct is not insulated, however, if there is a chance of heat gain from outside or there is any heat source near to that duct, insulation can be considered. 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 ... .