Duct system design guide first edition 2003 mcgill airflow corporation mcgill airflow corporation one mission park groveport, ohio 43125 duct system design i notice. Hvac course summary for ashrae book fundamentals of. No part of this work may be reproduced or used in any form or by any means graphic, electronic, or. Right sizing of an hvac system involves the selection of equipment and the design of the air distribution system to meet the accurate predicted heating and cooling loads of the house. With rightcommduct, compute duct and fitting size based on air flow with appropriate velocity limits, and let the software. The duct size calculator is a quick reference tool for approximating duct size and. In addition to the basic engineering guidelines for the sizing of hvac ductwork systems, the manual also provides related information on. Use 1 to compute the total air volume m 3 s, cfm in the main system. Duct sizing equal friction method engineering toolbox. No matter how much money you spend on a highquality hvac system, the equipment wont work at it s best without. This equalfriction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications. Research 105 abstract current duct design methods for variable air volume vav systems are based on the use of peak constant airflow. Related commercial resources ashrae handbook fundamentals chapter. The general guidelines state that if the winter design temperature for the location of the structure is above 35f, then both perimeter floor and ceiling distribu.
This has included active participation in technical and standards committees for professional organizations that serve the hvac industry, such as ashrae, astm, amca, and smacna. Determine the maximum acceptable airflow velocity in the main duct. Handbook of heating, ventilation and air conditioning. Available computer programs are simply automated versions of these manual procedures. It would be helpful if duct design 5 sizing the ducts contained the duct size formulas for round steel, rectangular, and flex ducts, similar to how you. Duct design quick introduction duct sizing tools and methods recommended duct velocities and noise effects duct fitting pressure losses do and donts of duct design. Related commercial resources chapter 35 duct design bernoulli. This results in lower first costs due to eliminated fittings but re. Chapter 21 of ashrae handbook fundamentals, for instance. Some chapters are followed by an additional section called extras which contains extra information about a certain topic previously. Duct sizing, june 1977 2 airah application manual duct design da3, 1987 3 ashrae handbook of fundamentals 2001 4 smacna hvac systems duct design 3rd edition 1990.
Ashrae american society of heating, refrigerating, and air. American society of heating, refrigerating and air. There is a dearth of detailed advice in common hvac design handbooks describing how to design ductwork for vav systems. Air flow problems have plagued the hvac industry for years. Heat conduction and thermal resistance for steady state conditions and one dimensional heat transfer, the heat q conducted through a plane wall is given by. Download hvac duct construction tables according to smacna and rule of thumbs pdf. Ductwork sizing, calculation and design for efficiency the.
Chapter 21 of ashrae handbook fundamentals, for instance, provides three suggestions for duct sizing friction rates but. The table below can be used to compare equivalent diameters for rectangular and round circular ducts, ductwork sizing, friction loss, sheet metal gauges, etc. Ansismacna 0062006 hvac duct construction standards. However, vav systems operate much of the time at an offpeak load condition and the impact of varying airflow rates to the sizing of duct systems has not been considered. This 3hour hvac training online video series provides guidance on how to properly use a friction chart andor accas duct slide rule values for sizing duct in the field. The equal friction method for sizing air ducts is often preferred because it is quite easy to use. In addition to the basic engineering guidelines for the sizing of hvac ductwork systems, the. Limits generally, the indoor temperatures are limited only by the type of equipment used and the design of the duct system.
Residential duct sizing guide the following duct sizes are based on a fraction drop of. Duct sizing and construction tables according to smacna pdf. Another important factor in the installation process is to make sure the duct work is sized properly. Design cfm 4 cfm 6 cfm 8 cfm 10 cfm 12 60 6x4 60 4x6 90 4x8 120 4x10 150 4x12 90 8x4 110 6x6 160 6x8 215 6x10 270 6x12 120 10x4 160 8x6 230 8x8 310 8x10 400 8x12 150 12x4 215 10x6 310 10x8 430 10x10 550 10x12 180 14x4 270 12x6 400 12x8 550 12x10 680 12x12 210 16x4 320 14x6 490 14x8 670 14x10 800 14x12 240 18x4 375 16x6 580 16x8 800 16x10 950 16x12 270 20x4 430 18x6 670 18x8 930 18x10 1100. Depending on the type of ducting and the cfm of the exhaust fan, table 7. The ashraefundamentals handbook contains hvac design criteria for most countries around the world. Compute the necessary air volume flow m 3 s, cfm in every room and branch of the system. Duct system sizes and airflow quick chart created date. This manual provides the hvac system designer detailed information on duct design and u. Fundamentals distribution systems 2 space availability the sizing criteria will often be defined by the space available to run the ductwork figure 1. Fellow ashrae 0 f the three duct design procedures recommended by the 1997. Fellow ashrae 0 f the three duct design procedures recommended by the 1997 ashrae handbookfundamentals, only the tmethod incorporates life.
Ansismacna 0062006 hvac duct construction standards eli p. Free ductwork tables for sizing and construction of hvac air ducts. From ashrae fundamentals handbook, the following equations may be used to convert rectangular and flat oval ducts to and from round. New duct sizing calculator available from ashrae and adi. Duct design clicking on a companys name will take you to their web site. No part of this work may be reproduced or used in any form or by any means graphic, electronic, or mechanical, including photocopying. The fourth edition of hvac systems duct design presents the basic methods and procedures required to design hvac air distribution systems. This document is a summary for ashrae book fundamentals of hvac systems, and it was prepared to cover the majority of the contents discussed in the book by giving a brief description about each topic, meanwhile keeping the meaning clear and simple. Deficiencies in duct design can result in systems that operate incorrectly or are expensive. The traditional duct sizing methods are equal friction and static regain ashrae, 2001. Ceiling plenums, duct chases, and obstructions such as walls and beams often dictate that a certain size duct be used, regardless of whether or not it is the best size from a. 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. Figure 3 is a sketch of an air conditioning cycle plotted on a psychrometric chart.
The course concludes with the basic instructions for filling out a manual d speedsheet. Duct design quick introduction duct sizing tools and methods recommended duct velocities and noise effects duct fitting pressure losses do and donts of duct design duct applications as 4254. Larger volumes or higher static pressures should be dealt with on an individual. Clicking on a companys name will take you to their web site.
The length of duct used for design purposes that includes the. Rightcommduct is a fast, easytouse commercial duct sizing and calculation software that takes full advantage of ashraes precision measurements and duct fitting database. Ordinary heating, ventilating, and air conditioning duct systems read air pressures at 0. Right sizing the hvac system begins with an accurate. Most of the time however, the round size is known, and the designer wants to.
You can obtain these from ductwork manufacturers or from industry bodies such as cibse and ashrae. Over sizing systems cost more and does not maintain the desired air flow and undersized duct work causes the system to strain mechanically and can be noisy. The duct size calculator is a quick reference tool for approximating duct size and equivalent sizes of sheetmetal duct and flexible duct. The following equations calculate the round duct diameter that will give the same friction loss as the rectangular or flat oval duct, at the same volume flow rate cfm. Principle of duct design in hvac systems cedengineering. Office tools downloads duct calculator by marinsoft, inc. New ductsizing calculator available from ashrae and adi. Hvac course summary for ashrae book fundamentals of hvac. Mar 18, 2018 this document is a summary for ashrae book fundamentals of hvac systems, and it was prepared to cover the majority of the contents discussed in the book by giving a brief description about each topic, meanwhile keeping the meaning clear and simple. Small ducts 66 design velocity 66 maximum velocity 67 sizing high pressure ducts 68 return air ducts hvac.
Online ductulator duct size calculator ductcalc online duct. If you dont have one, you can find them in the following links. Department of energy building america technical update meeting on april 2930, 20, in denver, colorado. Both methods were developed as expedient practical procedures and neither addresses optimization. Jun 09, 2017 it would be helpful if duct design 5 sizing the ducts contained the duct size formulas for round steel, rectangular, and flex ducts, similar to how you included the friction rate formula in duct design 4. Residential main supply trunk ducts, nonzoned systems. Velocity duct sizing chart residential main supply trunk ducts, nonzoned systems target velocity of 800fpm used listed by air quantity, round duct size and nearest square duct size 500cfm 11o or 10 x 10 1,300cfm 16o or 14 x 16 600cfm 12o or 10 x 12 1,400cfm 18o or 16 x 16. Howard, iii sheet metal and air conditioning contractors national association. To size the ducts youre going to need a duct sizing chart. Ashrae, adi release new duct sizing calculator the. Fellow ashrae 0 f the three duct design procedures recommended by the 1997 ashrae handbookfundamentals, only the tmethod incorporates lifecycle cost.