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.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 …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. Duct Calculator EliteTM 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 EliteTM features a highly intuitive interface which allows users to easily enter values with precision ... 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 … 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 26, 2023 · About this app. This app is developed to Calculate Duct Size Required with available CFM & FPM. This app calculate Both Rectangular and Round Duct Sizes in Inches. This App is also Calculate Air Flow rate in CFM and this app is also calculate in Air Velocity in FPM. The application is designed for engineers HVAC working in the field of design ... 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 … 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 ... 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!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 …Jul 22, 2022 · Step 1: CFM – System Size & Blower Size. Sizing an HVAC System. Step 2: Maximum Friction Rate. Friction Rate and Ductwork Length. What is TEL? Step 3: Maximum Velocity. Summary of Ductwork Sizing Factors. Our Recommendation. The Pick HVAC Ductwork Calculator. 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. 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.Air Duct Calculator. KALK.PRO's duct calculator will help you estimate the required duct size of the ventilation system for quality air exchange …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 ...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...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 …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 …Enter the square footage and height of your kitchen. Select the type of heating equipment. Specify the number of hood duct turns or ignore it. Click the " Calculate " button. Kitchen Range Hood calculator will help you estimate the exhaust ventilation capacity by kitchen size to remove heat, odors, moisture, and smoke. 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 ... 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: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.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 …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 ...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 …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 ... 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 … 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 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 ...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 …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 …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 moreDuctulator is an engineering tool to calculate air duct dimensions based on air-flow, duct material, roughness and pressure or velocity. It supports round and rectangular duct options and provides accurate and easy to …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 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 pressure loss. Friction loss calculation is made in rectangular or round ventilation ducts. Fill in the form below. Unit system. : Duct type. : Duct position.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.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 …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 Ducts50°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. 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. 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 …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.Air Duct Calculator. KALK.PRO's duct calculator will help you estimate the required duct size of the ventilation system for quality air exchange …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.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.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.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 …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% ...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. 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 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 ...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.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 ... FPM. Max. Static Loss/100ft: InWg. Free online ductulator for sizing of HVAC ducts. 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 …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 - …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 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 …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.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 …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 ...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 …AllDuctCalc™ - HVAC Air Duct Calculator v2 Updated 10/26/15: Provide inputs in the blue boxes, other inputs optional.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 …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.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.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 Engineering ToolBox (2004). Air Duct Calculator. [online] Available at: https://www.engineeringtoolbox.com/air-duct-calculator-d_813.html [Accessed Day …The pressure drop across a valve can be calculated using the valve’s Cv (flow coefficient) value and the flow rate. The equation is: Pressure Drop (psi) = (Cv × Q^2) / (SG × ΔP) where Q is the flow rate (in gallons per minute), SG is the specific gravity of the fluid, and ΔP is the pressure drop across the valve.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.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) 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 ... 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) 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. 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.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 …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.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 ...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 …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.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 Ducts 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 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 …. Ortex
Aug 26, 2023 · About this app. This app is developed to Calculate Duct Size Required with available CFM & FPM. This app calculate Both Rectangular and Round Duct Sizes in Inches. This App is also Calculate Air Flow rate in CFM and this app is also calculate in Air Velocity in FPM. The application is designed for engineers HVAC working in the field of design ... 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 …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 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 …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 …These include the AC duct size calculator, air conditioning duct calculator, HVAC duct calculator, air duct size calculator, duct size calculator CFM, and duct sizing calculator. Each calculator is designed to take into account different factors and help you determine the proper duct size for your system. 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. 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.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.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 …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.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 …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 ...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 …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 …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..