" A conservative interpretation of Standard 62. Ducting layout to be matched as per the design of Energy Saving Products Ltd. The circuit of the cold air ducts is calculated for 100% of the necessary flow. approximately 14. 2011 ASHRAE HANDBOOK HVAC Applications Space Air Diffusion 21. The Canadian and IECC codes and ASHRAE 90. •Install horizontal flex duct hangers at least every 4 feet (1. To gain some insight into this, lets consider a 12” square elbow with a 12” centerline radius (i. However, modern instruments claim accuracy as low as +/-3% with a measurement range up to 6,000 fpm. LinaTex® is a textile fiber duct liner specifically designed for lining sheet metal ducts in HVAC systems. Also determine the diameter of the duct if the air velocity is not to exceed 4 m/s. 15 cfm/ft 2 (1. CV 300 CFM Volumetric offset air, 10% of exhaust maximum. " When energy cost is high and installed ductwork cost is low, a lower initial air velocity is most economical. The variation between the temperature of the buildings in summer and the air in the cold air duct is 50 to 55. Main duct size, circular area =. 15 Measurement and Instruments (table 4) Pitot tube is a Standard instrument for measuring duct velocities It can measure air velocity in the duct from 0. STANDARDS Velocity Traverse of Air Ducts P. 06”wc to be safe) – Check the velocity of the air and increase the duct size if the velocity is greater than 900 fpm. The effects of exhaust air velocity on grease deposition in kitchen exhaust ductwork. NAIMA AH116 : FIBROUS GLASS DUCT CONSTRUCTION STANDARDS LOW VELOCITY SYSTEMS 2" w. Other duct provides 100%. 5 2 3 38 9 5. 0% cumulative frequency of occurrence for indicated month, °C; mean coincident wet-bulb temperature, °C. This standard applies to sound sources connected to a duct. ), 1/2" Bar Spacing (4MJN8)? Grainger's got your back. 35 air change per hour (ASHRAE, Standard 62, 1989). For Institutional Occupancies, the limit is reduced to 50% (13 lbs/1000 ft3). friction of turning air. FLEX AIR™ provides for easy installation and full flexibility in vent locations. ): Round Duct Equivalent Diameter (in. If conditions are very good, an accuracy of ± 5 or 10 percent may be obtained this way. LinaTex® is a textile fiber duct liner specifically designed for lining sheet metal ducts in HVAC systems. Rate” or “Air Velocity”. For example, all things being equal, an 8” duct at the end of a long convoluted duct system will not deliver as much air as an 8” duct on a very short straight system. A technician can adjust the calibration in the field. 0 m/s Stationary air. The impact of the turning vanes has a lot to do with both the geometry of the fitting and the velocity of the air moving through it. The preferred method of measuring duct volumetric flow is the pitot-tube traverse average. This tool will calculate the velocity in any units from the specified volumetric flow rate of a substance flowing through a rectangular duct of a defined width and height. The "standard rating condition" (certification rating point) airflow volumes for each terminal unit size are tabulated below per AHRI Standard 880. 9997)), and this was used to calibrate the mean duct velocity in later tests using the measured center velocity. Revit provides 4 standard methods for sizing duct: Friction Velocity Equal Friction Static Regain Friction and Velocity Methods When just the friction or the velocity sizing method is selected, sizing can be based on only the one method, or a logical combination of the friction and/or velocity methods. Grease duct is an ETL listed, single wall construction made from 430 stainless steel. the maximum flow rate and velocity depends in the type of usage generally it ranges from 2. The aerodynamic diffuser backpan ensures that the supply air has a smooth transition from the duct to the room. duct details (low velocity) r r=1-1/2w radius elbow w miter elbows & tees turning vanes in all elbows and tees flex connection acoustical liner size shown is clear air passage 24x16 duct offsets r=1-1/2w w less than 15° 15° to 30° greater than 30° 30° max 30° max transitions rectangular to round 45° w 4" min or 1/4w or 12" max. hotels), max. Operating Temperature Limit: 250°F (121°C) Maximum Air Velocity: 6,000 fpm (30. Duct calculators use 100′ as a reference distance. • Where possible use a single exhaust duct per dryer Sub Title • Dryers are to run with a positive outlet pressure. velocity in main ducts (for proper fan operation) is1200 fpm. 4 mtr /sec in ideal condition in case of special industrial application refer to ashrae standard and DW 144/143 and SMACNA standards. Filter Face Air Velocity (FPM) 295 Maximum Initial Resistance (Inches W. • ASHRAE 62. Duct Sizing : Galvanized Steel Fill in the Blanks. Friction losses vary according to ductwork type, length of duct, velocity of air, duct area, density of air, and duct diameter. Air velocity (max. Indoor moisture, altered airflows, lowered air exchange all have the ASHRAE Standard 62. tal duct is a reduction in deposition with decreasing exhaust velocity for the 4. pdfsdocuments2. EnviroAire Duct Board is ideal for residential HVAC applications to quietly and efficiently distribute cool or warm air for greater room-to-room comfort. Duct sizes of 6”, 8”, and 10” were tested in a positive pressure, blow-through configuration. A fiber reinforced, water-based, premium quality, UL- listed 181A-M/B-M, high-velocity duct sealant for commercial and residential supply and return air duct use. As the air moves down the duct, the velocity of the air becomes more uniform across the duct, and the static pressure increases as the velocity pressure decreases. 5 30 6 4 2 1. To gain some insight into this, lets consider a 12” square elbow with a 12” centerline radius (i. The number of sensing ports on each element, and the quantity of elements utilized at each installation, shall comply with ASHRAE Standard #111 for equal area duct traversing. Air Velocity Measurement in Ducts In order for air conditioning and ventilation systems to run smoothly and efficiently, the flow velocity in the ventilation duct must be regularly checked. 1% of flow on 3900 cfm system = 39 cfm. AIR DUCT ACCESSORIES. Thermal conductivity shall be no greater than 0. Heater air velocity = 1000 CFM/2 sq. characteristics at the branch ducts that are closest to the air-handling unit. Indoor Air Quality ANSI/ASHRAE Standard 62. are inside an air distribution duct system: “Where an evaporator or condenser. Chilled-water air-handling units have a similar requirement (effective January 2010); see "VAV requirements for chilled water air-handling units serving a single-zone," p. (or L/s), the aspect ratio and one of either the velocity of air or the friction loss per 100 feet (30 meters). Exhaust Stack Exit Velocity 0 100 200 300 400 500 Norm. * include fittings in the Duct TEL. Static pressure loss duct in. Determine (a) the volume flow rate of Solution. Based on the measurements obtained using this empty duct, a relationship between the mean duct velocity (y) and the velocity measured at the center of the duct (x) was developed (y = 0. galvanized steel enclosure frame. ASHRAE Standard 62-1981, Ventilation for Acceptable Indoor Air Quality. The team performed calculations for unaltered ducts and result-ing air velocities for a two-story 1960s house and examined air velocities and. 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. 54 m/s) for the 1. A VBASIC SPREADSHEET TO CALCULATE DUCT DIAMETER. Operating temperature (max. It is also possible to take a single reading to measure air velocity or air volume flow in a duct, measuring in the center of the duct and multiplying the reading by 0. 0 L/s) for the kitchen area and 20 cfm/person (9. Fan and Motor shall be of sufficient capacity to provide the required air movement. 1 requires that ve ntilation be increased by 25% when heating, if the above rules are not followed. ASHRAE Duct Noise vs Velocity. Maximum velocities range from 1400-1800fpm for round ducts and 700-1400fpm for half round ducts (the higher the inlet velocity, the more static pressure required). – The separation distance shall be greater than or equal to the distance prescribed in ANSI/ASHRAE Standard 62. 1”wc or less to size each metal trunk duct. Branch lines from VAV boxes to outlets are typically sized as. friction of turning air. Pull out slide has recommended duct velocities, recommended gauges for sheet metal, and much more. the system is constant volume and duct velocity does not exceed 1500 FPM. air velocity: main duct ≤ 10-12. Recommended for sealing connections on flexible duct or fiberglass duct board. These dampers have AMCA certified pressure drop and leakage performance that comply with ASHRAE 90. 1 recommends limiting the coil pressure drop to 0. Used in 3D-routed duct system consisting of connected components to compute and list the Velocity Pressure exiting change-in-flow or change-in-size components in the. Approximately 1 —1 / 2 duct diameters out. A duct section has a constant air quantity, constant velocity (size does not change) and constant shape (round, rectangular or oval). 5 m/s, return main duct ≤ 8 m/s, branch ducts ≤ 6 m/s. " A conservative interpretation of Standard 62. If the air flow velocity and volumetric flow are not set correctly, the room air quality may suffer. In addition, provide at least 3 diameters of straight flex duct at the dif-fuser inlet. The nominal condenser airflow is 2000 CFM. Ducts are normally isolated by 1″ deflection spring hangers that are installed up to 50′ from the fan discharge. Duct Sizing : Galvanized Steel Fill in the Blanks. 9 to 50 m/s with micro manometer. I will address this regarding designing HVAC systems. Therefore, to find the velocity V_e, we need to know the density of air, and the pressure difference (p_0 - p_e). Maximum friction rate (to limit fan power). What is the recommended air flow rate for air conditioning systems? How is HVAC air flow rate, air velocity, or CFM (cubic feet per. Air velocity is a function of air density and differential pressure, but determining air flow requires that the geometry of the piping be taken into account. 3 m/s). (1) Because this is an article on basic duct design, we will only consider systems where changes in elevation are unimportant, there is no heat transfer in the systems (adiabatic/ isothermal. ), 1/2" Bar Spacing (4MJN8)? Grainger's got your back. 25; and for wind velocity of 16 km/h, multiply by 2. Recommended design velocity for supply air in the main duct should not exceed 1200 fpm and of return air 600 fpm. 2 bhp per 1000 cfm). Apps Sponsored Links Air Duct Flow Air Duct Velocity Air Flow Head Loss Beam Supports. 3 Outdoor air and local exhaust airflow rates. Since 500 FPM exceeds the minimum, this installation is safe. Begin at the section farthest from the fan and work towards the fan. Designing laboratory ventilation systems One thing to note is that ventilation air is defined in ASHRAE 62. txt) or view presentation slides online. Indoor air quality is a complex issue. 1-2007, with the incorporation of more than 100 approved addenda, 52 HVAC- Load Calculation Check Least (Based on the AIRAH Handbook 3rd Edition) File Size: 27 Kb Heat load or heat gain A building or room gains heat from many sources. This tool will calculate the velocity in any units from the specified volumetric flow rate of a substance flowing through a rectangular duct of a defined width and height. Engineering ToolBox Mobile Apps - for online and offline use. Factors to consider are potential flow turbulence from fittings, available pressure, and sound generated by fast moving air. Without spiral round duct, here are a few of the things that could happen. ) – UL 181 2" w. Member ASHRAE. 6 µm par-ticles. Total air volume flow rate = 2. 25m3/s Main duct velocity = 7. Air Ducts - Friction Loss Diagram - A major loss diagram for air ducts - Imperial units ranging 10 - 100 000 cfm; Air Return Intakes - Sizes and Capacities - Size and capacity of. When you put the ducts in an unconditioned attic and have the minimum insulation allowed, you want to move the air at a higher velocity, pushing it up near the maximum recommended by ACCA Manual D, 900 feet per minute (fpm) for supply ducts and 700 fpm for return ducts. Use the Fluke 975 to optimize HVAC ventilation settings for ASHRAE 62 recommendations, to actively monitor conditions that promote a productive environment, and quickly and accurately. It is also possible to take a single reading to measure air velocity or air volume flow in a duct, measuring in the center of the duct and multiplying the reading by 0. 7 CFM/SF, or 133 ACH. 1-2010 VRP requires that if heating air supplied from the ceiling is less than 15— above room temperature but does not reach within 4. Operating temperature (max. Chapter 32 of the 1993 ASHRAE Handbook-Fundamentals shows how the basic Bernoulli equation is extended to analyze air flow through ducts in real systems. CV 300 CFM Volumetric offset air, 10% of exhaust maximum. This article was published in ASHRAE Journal, September 2011. Based on ASHRAE 2001 Fundamentals, Chapter 14. Introduction: This article presents an automated quick and simple equal friction solution to calculating duct diameter and pressure loss, using an iterative solution to the Colbrook equation. • Velocity pressure will only be exerted in the direction of air flow and is always positive. 5 30 6 4 2 1. water For standard air at sea level w = 0. The required air speed is called the "capture velocity". The 922 velocity and air flow calculations are based on standard air at 29. 1 (Proposed) Static Pressure Limit Maximum Air Velocity m/s Air leakage limts l/s/m2 Positive Pa Negative Pa Low pressure - Class A. COLUMN ENGINEER’S NOTEBOOK. Fungi resistance ASTM C1338 Meets requirements. All pipe sizes shall be designed in accordance with the latest version of ASHRAE Standard. 8 m) •Install flex duct so that sag does not exceed ½ in. The recommended velocities for the control of noise generation are different depending on the application; however, all categories fall within the range between 600 fpm (3 m/s) and 3,000 fpm (15 m/s) (Rowe 1988). Outside air from roof hood Direct‐drive fan array (4 fans) (535 CFM/BHP), N+1 8‐row, 8 FPI cooling coil sized for 400 FPM face velocity and 0. The media pack is installed into a heavy 24 ga. Many circumstances warrant measuring air veloci-ties or air flow, and a duct traverse is the most precise method of obtaining that information. AIR DUCT SLIDE RULE CALCULATOR Size: 4"x9. * include fittings in the Duct TEL. Duct calculators use 100′ as a reference distance. Air flows turbulently through ducts at between 2,000-6,000 feet per minute (fpm). 5, Air-to-Air Energy Recovery. This hvac duct sizing calculator is very simple and it calculates the duct friction loss value and air velocity inside the duct. Linear diffusers have a long zone2 Zone 3 Most of the induction occurs. 39 m3/s) of air has to be exhausted out, which one of the following is correct by considering, 2. • Maximum temperature difference between supply air and room temperature for effective mixing when heating, per ASHRAE handbook = 15°F (90°F discharge), continuous operation • 150 FPM must reach 4. Title • Maximum exhaust duct length: • Type 1 dryers = 35 equiv. 54 m/s) for the 1. Duct Velocity Criteria 1. The energy saving trend is to reduce exhaust air. In general, natural air velocity provides a stronger cooling effect and better thermal comfort (Cui et al. Maximum spacing between supports shall not exceed the maximum spacing per manufacturer’s. Your air duct velocity should be kept within set limits in order to lower noise and excessive friction. This table assumes no elbows. Description: air ventilation applications. * include fittings in the Duct TEL. 4 force of air within a duct, measured in average room temperature at a coincident air velocity less than 70 FPM. 4 m/sec) Fungi resistance – ASTM C 1338 Does not breed or promote Fungi resistance – ASTM G 21 No growth. Duct silencers are shown on intake and discharge openings to room, a screen is on the outside. American Soci-ety of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. 7 CFM/SF, or 133 ACH. 1-2010 as that portion of supply air that is outdoor air plus any recirculated air that has been treated for the purpose of maintaining indoor air quality (IAQ). Enter a new value to override the default value, as required. A big part of any HVAC project is calculating duct flows, pressure losses, converting duct flow volumes etc. ) – UL 181 6000 fpm (30. , Air ducts may be in circular, square and in rectangular shapes. Apps Sponsored Links Air Duct Flow Air Duct Velocity Air Flow Head Loss Beam Supports. The most common design indoor temperature (dry bulb) is. 5 m/s as the face velocity? 1) Face area of the louvre with 50% free area is 1. Indoor Air Quality ANSI/ASHRAE Standard 62. • All ducting to be insulated in an unconditioned space. Krueger is a leading manufacturer of air distribution solutions, including grilles, registers, diffusers, terminal units, chilled beams, displacement ventilation, critical room and underfloor products. Simply state d, these long ASHRAE HANDBOOK 25 or more points, maximum 6 or 8 inches apart, depending on duct size 12 to 30 points, along 2 or 3 diameters AMCA. ASHRAE Duct Noise vs Velocity - Free download as PDF File (. 1-2013) This proposed addendum modifies the language to provide an efficiency rating for. Recommended Main Supply-Air velocities for rigid duct should be 700-fpm & a Max of 900-fpm, for flex duct 600-fpm. The recommended velocities for the control of noise generation are different depending on the application; however, all categories fall within the range between 600 fpm (3 m/s) and 3,000 fpm (15 m/s) (Rowe 1988). ACCA Manual D Recommended Velocity (FPM) Supply Side Return Side Recommended Maximum RecommendedMaximum. As the air moves down the duct, the velocity of the air becomes more uniform across the duct, and the static pressure increases as the velocity pressure decreases. 5, Air-to-Air Energy Recovery. • Type 1 dryers between +0. 4 illustrates the maximum limits of air velocity in relation to the classes of CEN 15251 (2007). tal duct is a reduction in deposition with decreasing exhaust velocity for the 4. 1 user's manual. 4 m/sec) Fungi resistance – ASTM C 1338 Does not breed or promote Fungi resistance – ASTM G 21 No growth. 2,000 fpm velocity • Maximum temperature 165ºF ASHRAE Standard 62 or California. Air temperature, air velocity, humidity, and globe temperatures were measured using a mobile cart at the heights indicated below, with the exception of the one stationary observation point. characteristics at the branch ducts that are closest to the air-handling unit. NR511 Final Exam Study Guide NR511 Final Exam Study Guide Week 1 1. I do have one room that is sensitive to duct noise (home theater type room) so I wan tto minimize sound there. ) – ASTM C 1071 6000 fpm (30. VAC piping is typically sized using rules-of-thumb such as maximum friction rate or velocity, or a combination of the two. Properly located air registers will solve the draft issue. 1-2007, with the incorporation of more than 100 approved addenda, 52 HVAC- Load Calculation Check Least (Based on the AIRAH Handbook 3rd Edition) File Size: 27 Kb Heat load or heat gain A building or room gains heat from many sources. SL) Rectangular (TD) 50 5" 8 x 6 75 5" 8 x 6 100 6" 8 x 6 3½ x 10 (110) 125 6" 8 x 6 3½ x 12 (140). approximately 14. * include fittings in the Duct TEL. A duct traverse consists of a number of regularly spaced air velocity and. The ASHRAE HVAC Duct Sizer application allows you to quickly size one HVAC duct run or a range of duct sizes using the constant friction method. air velocity: main duct ≤ 10-12. 3 (Duct Friction Chart), is obtained the friction loss as 0. 0% cumulative frequency of occurrence for indicated month, °C; mean coincident wet-bulb temperature, °C. The low-speed airflow can be the larger of the limit stated above or the ASHRAE 62. 02 perms or less. Inside the tank I have 30 psi gauge pressure (~207 kPa) and the diameter of the nozzle is 1. 1 ASHRAE Research Project 1033-RP Final Report, "Effects of air velocity on grease deposition in exhaust ductwork," documented that grease deposition is reduced as air velocity is reduced. galvanized steel, welded casing in 8" depth with 90º connecting flanges in a configuration and size equal to that of the duct it is mounted into. Dougherty, P. This parameter shall be measured and recorded at no less than 10 Hz. All other duct systems such as return and exhaust, including branch ducts, shall be designed for a maximum velocity of 1500 fpm for the duct mains and a maximum static pressure of 0. The nominal condenser airflow is 2000 CFM. The preferred method of measuring duct volumetric flow is the pitot-tube traverse average. Note: Air velocities for the initial 10 ft of duct extending from supply register or return grilles should not exceed the values given in the table by more than 20 percent. Since 500 FPM exceeds the minimum, this installation is safe. The ASHRAE HVAC Duct Sizer application allows you to quickly size one HVAC duct run or a range of duct sizes using the constant friction method. people is described by ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) in their comfort chart. That means no more than 1" of sag between hangers. Indoor air quality is a complex issue. Duct calculators use 100′ as a reference distance. FLEX AIR™ provides for easy installation and full flexibility in vent locations. Operating temperature ASTM C411 250°F (121°C) Maximum air velocity UL 181 Erosion test and ASTM C 1071 6,000 fpm (30. We assume no liability for use of this program. A Pitot tube should be inserted at least 8-1/2 duct diameters downstream from elbows, bends or other obstructions which create turbulence. High air velocity inside fan coils and over cased coils resulting in higher bypass factor and lower latent heat removal High TESP (Total External Static Pressure) due to high duct velocity Duct FPM can be measured using a pitot tube and a sensitive manometer, induct vane anemometers like the Testo 416 or a hot wire anemometer like the Testo 425. It is important to determine the 100% Effective Duct Length to ensure uniform air discharge. 2 Outdoor air required Section revised and new provisions added to align the mechanical ventilation requirements for R-2, R-3, and R-4 buildings of three stories or less above grade plane 403. Other systems such as dust collection or conveying of solid materials are usually based on constant velocity principles. Apps Sponsored Links Air Duct Flow Air Duct Velocity Air Flow Head Loss Beam Supports. Ducts, Fan Inlets & Fan Arrays Our precision Vortek G3 Airflow Measurement products provide accurate, linear airflow measurement for duct insertion, fan inlet and fan array installations. air handling unit, rooftop unit or fan coil) and dis-tributes the air around the building. FPM – Velocity of Air in feet per minute. ASHRAE Indoor Air Quality Air 35 Use velocity pressure probes or stations • 1250 fpm max free area velocity Standard 500-L Louvers. within the duct section = Flow velocity (mis) = Air density (m3/kg) = Energy demand cost (cost/kW) = Unit electrical energy cost (cost/kWh) About the Authors Robert W. 5, Air-to-Air Energy Recovery. diameter of the duct if the air velocity is not to exceed 8 m/s. feet (each elbow = 5 feet). 6 µm par-ticles. Testo 440 Offers. of wg, which is less than the 0. 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. air velocity: main duct ≤ 10-12. * include fittings in the Duct TEL. Cavanaugh, and L. However, velocity pressure losses are excessive and velocities more than 4,000 fpm are not recommended. So if you have a two-ton system, you need ductwork that will carry 800 CFM. Based on these formulas, Dryer-Ells can be measured the same as straight pipe. Air velocity is a function of air density and differential pressure, but determining air flow requires that the geometry of the piping be taken into account. A = cross sectional area of hood opening in square meters. ASHRAE SPC215P and the SMACNA HVAC Duct Construction Standards Manual, 4th edition. The low-speed airflow can be the larger of the limit stated above or the ASHRAE 62. This will be the System design point for creating the following Table:. It can lower the dust loading of conventional filtration as it is designed to separate large size sand particles at low to medium speeds. • Flex duct must be strapped every 5 feet with no sags more than 1½" in 5', or sharp direction changes. Face Velocity The velocity of supply air as it leaves the supply outlet. 6 out of 5 stars 53. One six-inch round duct is good for about 120 CFM, a six-inch duct carries about 150 CFM, and eight-inch carries about 200 CFM of cool air. ASHRAE 15 - 2013 §8. However, modern instruments claim accuracy as low as +/-3% with a measurement range up to 6,000 fpm. 5–15 Air enters a 28-cm diameter pipe steadily at 200 kPa and 20°C with a velocity of 5 m/s. 075 pounds per cubic foot), the relationship is: Equation 1. It is resistance to air at rest in a duct, and is also commonly called “resistance”, “friction”, “friction loss”, or “pressure loss. This permits use of the maximum allowed run length. Pure earth atmosphere, at 70°F with 50% relative humidity and devoid of smoke particles, mold spores, air-bourne pathogens, plant pollen, respirable dust and with oxygen and carbon dioxide levels that remain constant despite our breathing - would be ideal, but terribly impractical. ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Please provide CFM Please enter only numbers for CFM Minimum value for CFM is 30 Maximum value for CFM is 100000 Friction Loss{per 100ft of duct} * Please provide Friction Loss Please enter only numbers for friction loss Minimum value for friction loss is 0. In general, Fabric Diffusers operate at similar air flow velocikes to tradikonal duckng. Each chemical hood, laboratory, facility, or site must define the acceptable average face velocity, minimum acceptable point velocity, and maximum standard deviation of velocities, as well as when ASHRAE/ANSI 110 or visualization testing is required. • For accurate control, the minimum setting guideline should not be lower than 2 m/s inlet neck velocity for units using inlet velocity sensors. The result is that the fan is producing that much more work in the form of cooling. This module is fully integrated with Right-Draw ® and all load calculation modules for accurately sized ducts. In order to help you we have devised our own mini calculation "apps" feel free to use them as much as you want, if you need any help please don't hesitate to contact our technical gurus at MAS. ) - UL 181 2" w. The energy usage of the system has been designed to meet the current ASHRAE Standard 90. 7 m/s) and a maximum allowable duct friction loss rate of 0. At point A in Figure 1, the VP is high and the available SP is low. The index run is the duct run with the maximum external static pressure drop. Even with higher air velocities in round ductwork, the sys-tem uses the same or lower fan static pressure — total fan. DUCT DESIGN & FORCE AIR HEATING. This chart based on maximum velocities of 1000 to 1100 fpm—well within the good practice recommendations. Standard ESP 104. As the air moves down the duct, the velocity of the air becomes more uniform across the duct, and the static pressure increases as the velocity pressure decreases. The Fluke 975 AirMeter test tool raises indoor air monitoring to the next level by combining five powerful tools in one, rugged and easy-to-use handheld device. It is used in large duct and plenums and has an air velocity rating of 6,000 FPM (30. Include plans, elevations, sections, details and attachments to other work. CBE Thermal Comfort tool to calculate thermal comfort according to ASHRAE Standard 55-2017, thermal comfort, PMV, PPD, SET, Adaptive comfort, Center for the Built Environment, CBE, UC Berkeley, Predicted Mean Vote, Predicted Percentage of Dissatisfied, Standard Equivalent Temperature, Ole Fanger, Richard de Dear, Gail Brager, Draft, Draught, Air Movement, Metabolic activity, Clothing. Duct calculators use 100′ as a reference distance. Laboratory Ventilation Standards Industrial Ventilation - ACGIH • Fume hood face velocities between 60-100 fpm • Maximum of 125 fpm for radioisotope hoods • Duct velocities of 1000-2000 fpm for vapors, gasses and smoke • Stack discharge height 1. 75 (25% safety factor) = 751 fpm. – Maximum m (mass flow rate) or – Exhaust ducts discharging other product (heat, odors, smoke, etc. 9, Section 5. All Hart & Cooley insulated flexible air ducts are certified by the Air Diffusion Council for thermal performance in accordance with the ADC Flexible Duct Performance & Installation Standards (1996). Duct Traversing for Average Air Velocity and Air Volume The velocity of an air stream in a duct is not uniform over the cross section of the duct. High air velocity inside fan coils and over cased coils resulting in higher bypass factor and lower latent heat removal High TESP (Total External Static Pressure) due to high duct velocity Duct FPM can be measured using a pitot tube and a sensitive manometer, induct vane anemometers like the Testo 416 or a hot wire anemometer like the Testo 425. stribution Outlets. 4 m/sec) Fungi resistance – ASTM C 1338 Does not breed or promote Fungi resistance – ASTM G 21 No growth. Friction Rate The pressure loss between two points in a duct system that are separated by a specific length. 3 m/sec), install metal nosing on edges of duct liner facing air stream. Thermaduct™ offers industry solutions to outdoor ductwork that exceed the ASHRAE and ICC Energy Codes present today and those 10 years from now. 1 (maximum 1. The low-speed airflow can be the larger of the limit stated above or the ASHRAE 62. [20 Pa] maximum FIGURE 5 Other transfer air options. Air velocity limitation sets the boundaries for duct sizes. Operating Temperature Limit: 250°F (121°C) Maximum Air Velocity: 5,000 fpm (25. He is mem­ ber of ASHRAE Technical Committee 5. 0 m/s Stationary air. The results of an important CFD study on the impact of make-up air velocity used to control smoke in atriums is reported. It is important to determine the 100% Effective Duct Length to ensure uniform air discharge. 4 m/min (500 ft/min). You can rely on testo 440 kits for measurements in. 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. p) Controller Output (CO expressed in Volts): Control output to the controlling exhaust air valve. STANDARDS Velocity Traverse of Air Ducts P. The Fluke 922 converts velocity pressure to velocity automatically when in Velocity mode. 1-201x, Energy Standard for Buildings Except Low-Rise Residential Buildings (addenda to ANSI/ASHRAE/IESNA Standard 90. When the air handler or return duct is located in the garage, the ductwork for the HVAC system must be sealed to have air leakage of no more than 6% of the air handler airflow when measured at 0. 06”wc to be safe) – Check the velocity of the air and increase the duct size if the velocity is greater than 900 fpm. From the chart, the corresponding pressure drop is 0. 1 ventilation requirement for the zone. 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. DETECTOR INSTALLATION [5. ACCA MJ8 Air Conditioning Contractors of America publication Manual J Residential Load Calculation Eighth Edition ACH50 Air Changes per Hour at 50 Pascals ACHn Air Changes per Hour Natural AED Adequate Exposure Diversity ALP Average Load Procedure ASHRAE American Society of Heating, Refrigeration and Air-Conditioning Engineers. For Institutional Occupancies, the limit is reduced to 50% (13 lbs/1000 ft3). According to ASHRAE Standard 8, occupied spaces should be controlled to limit the indoor humidity to a maximum dew point temperature of 60°F, which — assuming an ASHRAE-recommended comfort level dry-bulb temperature between 72°F and 78°F9 — corresponds to a maximum relative humidity level of between 55-65 percent RH. 1-2013 (I-P Edition) 63 Small duct high velocity, air cooled <65,000 Btu/hb All Split System 11. The testo 425 air velocity meter measures the air velocity and automatically calculates the volumetric air flow. Similarly, significant reductions in air velocity require only modest increases in duct size. a maximum smoke-developed index of 50, for both insulation and adhesive, when tested according to ASTM E 84. 5 feet of the floor at 150FPM the outdoor air supply must be increased by 25%. Additional parameters can be specified such as the duct shape (rectangular, round, or oval), the air temperature and the air pressure. cooling CFM and air velocity. • Type 1 dryers between +0. 1 ventilation requirement for the zone. 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. When the air handler or return duct is located in the garage, the ductwork for the HVAC system must be sealed to have air leakage of no more than 6% of the air handler airflow when measured at 0. 1%: N/A: General Specifications: Operating temperature CO and. Typical Dryer Manufacturer's Requirements • Where possible use a single exhaust duct per dryer Sub Title • Dryers are to run with a positive outlet pressure. Quantifying System Effects The current ASHRAE Handbook — HVAC Applica- tions recommends that silencer pressure drops, includ- ing system effects, not exceed 87 Pa (0. And it shows the velocity and/or static pressure loss of air for both types of duct shape. ) - UL 181 6000 fpm (30. • Buildings do not have operable windows. The SMACNA HVAC Systems−Duct Design manual is intended to be used in conjunction with the American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc. To minimise the risk of generated noise, we would suggest that the following maximum duct velocities should be adhered to. It helps HVAC engineers and technicians more accurately size ducts, especially flex ducts under varying amounts of compression. In general, Fabric Diffusers operate at similar air flow velocikes to tradikonal duckng. 2 tests are to be conducted at one of seven airflow rates:. For swaged pipe use multiplier of 1. 25" Material: Heavyweight coated calculator board Production: Each order is custom manufactured with your company information and in your choice of. V = 4005 x √ΔP) V = 4005 x √0. According to CIBSE Guide B – HVAC / 2005, clause 3. Building or room exhaust fans must be sized large enough to attain these standards. 1 and IECC leakage requirements for non-motorized dampers. 1 m/s May be used as the assumed internal air velocity in some simple heat transfer calculations. It is resistance to air at rest in a duct, and is also commonly called “resistance”, “friction”, “friction loss”, or “pressure loss. •Use flex duct supports that are ridged and at 1. And better, from Annex A (Explanatory Material): A. •Sub Type 2 dryers between +0. A duct section has a constant air quantity, constant velocity (size does not change) and constant shape (round, rectangular or oval). ) – ASTM C411 250°F (121°C) Air velocity (max. • ADPI is essentially a measure of the degree of mixing in zones served by overhead cooling systems. For VAV fume hood systems, an exhaust diversity factor may be used for the maximum duct velocity. If conditions are very good an accuracy of ±5 or ±10 percent may be obtained this way. These air volumes equate to an approximate inlet velocity of 2000 fpm (10. • Duct Mastic must be applied to cover all possible air leaks at duct connections, boot connections, plenum edges and corners. Heater air velocity = 1000 CFM/2 sq. The aim of these criteria is to set a limit for. Duct systems fabricated from fibrous glass duct board. This table assumes no elbows. What is the recommended air flow rate for air conditioning systems? How is HVAC air flow rate, air velocity, or CFM (cubic feet per. A reasonable starting friction rate for VAV systems is. Choosing an auto-changeover diffuser does not change the ASHRAE 62. The supply air velocity measured at the register face determines how far the throw of the air will be. 2, page 5-2). Flow Visualization 5. If the fan has the static capacity to overcome the additional energy restriction related to a higher velocity, the section of the duct may experience. Airius introduces a quieter air circulation solution,. Generally, the velocity should be no more than 700 FPM. A working turndown of 3 to 1, or a minimum velocity of approximately 800 FPM, was accepted as the minimum airflow rate that airflow measurement devices needed to operate at. Unless there is fan powered equipment in the ceiling, we like an NC 35 acoustical enviromnent. ASHRAE 111 states that a Pitot-static tube traverse is not practical below a 600 fpm (feet per minute) velocity, and manufacturers of digital manometers intended for the purpose generally don’t recommend using Pitot tubes below 1,000 fpm. A further velocity limitaon may be needed to flow turbulence, which can cause vibraon of the fabric. Hanger Spacing, Hanger Rod Diameter and Angle support Size. The Canadian and IECC codes and ASHRAE 90. 1* The air velocity through any duct shall be not less than 152. (560 mm) round duct, but a colder SAT system will. 64 = 1894 fpm. 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. 15 m/s and above May be felt as a draught in a cold climate in the winter. •For a specified cross-sectional area and mean air velocity, a round duct has less fluid resistance against airflow than rectangular and flat oval ducts. cooling CFM and air velocity. 810 Cold air boot, collar, duct 45- 65' EL AIR FLOW DYNAMICS & DUCT SIZING REFERENCE GUIDE SUPPLY OR RETURN DUCT SIZE/CAPACITY (. So if you have a two-ton system, you need ductwork that will carry 800 CFM. Duct calculators use 100′ as a reference distance. 1 (maximum 1. ) – ASTM C1071 6,000 fpm (30. 9, Section 5. Designing for Comfort. To gain some insight into this, lets consider a 12” square elbow with a 12” centerline radius (i. duct connection to the low pressure duct above the ceiling—at least 6 ft (1. 4 mtr/sec to 3. •Sub Type 2 dryers between +0. Description Style 2 filters shall be identical to Style 1 filters except being provided with three. NFPA Compliance: Install duct systems in compliance with NFPA 90A “Installation of Air Conditioning and Venting Systems”. TEAS ATI PRACTICE QUESTIONS 1 Which of the following correctly lists the cellular hierarchy from the simplest to most complex structure? a. For the air outlet provide s-slip and drive connections. Eventually, the supply air will slow enough to become ineffective in mixing with room air. As the air moves down the duct, the velocity of the air becomes more uniform across the duct, and the static pressure increases as the velocity pressure decreases. Standard 62. of water (50 ft of EL) – Mentions Entrance Fitting. flex duct will only deliver 160 cfm up to 25 ft. There is no limitation on the length of runs when using UL Listed Air Ducts. Attach the testo 440 air velocity and IAQ measuring instrument to metal surfaces (e. Clean Room Make-up Air Units Outside air make‐up AHU design with complete temperature and humidity control. The results of an important CFD study on the impact of make-up air velocity used to control smoke in atriums is reported. A reasonable starting friction rate for VAV systems is. 075 lb m/ft3 • V = 4005 (V P)0. txt) or view presentation slides online. 556 m2 (which means, free area of the louvre is 0. The testing was done in compliance with ASHRAE Standard 120-1999, Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings (ASHRAE 1999). Consider the cross section of a rectangular duct, characterized by its aspect ratio α* = 2b/2a, as shown in Fig. This is reflected in the latest revisions of the 2016 and 2013 ASHRAE Handbooks1,2 along with ASHRAE Standard 90. 2011 ASHRAE HANDBOOK HVAC Applications Space Air Diffusion 21. 16 ADC Flexible Duct Performance & In stallation Standards, 5th Edition Flexible ducts may rest on ceiling joists or truss supports. 5 30 6 4 2 1. For ducts wider than 18 inches with velocities less than 500 fpm, it is rec-ommended that multiple detectors 18 inches maximum on center be installed. The advent of enhanced Indoor Air Quality (IAQ) has influenced engineers to 1) keep interior ducts free of foreign materials that. Indoor moisture, altered airflows, lowered air exchange all have the ASHRAE Standard 62. The number of sensing ports on each element, and the quantity of elements utilized at each installation, shall comply with ASHRAE Standard #111 for equal area duct traversing. Nominal area of duct connection to air outlet or inlet. Duct calculators use 100′ as a reference distance. 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. The flow rate through the nebulizer and the diameter of the injection tube outlet shall be adjusted to provide an injection air velocity within + 50% of the mean duct velocity. ft/min Feet per minute. within the duct section = Flow velocity (mis) = Air density (m3/kg) = Energy demand cost (cost/kW) = Unit electrical energy cost (cost/kWh) About the Authors Robert W. For the air inlet provide round stub connection for duct attachment. Calculations are for 60°F dry air at sea level, from 5 to 3000 cfm (approximately standard air which is 0. Then size of rectangular duct is calculated considering minimum aspect ratio. Downstream of the mixing boxes the rectangular duct would typically be provided as “S & drive” transverse connection duct with “snap-lock”. Permacote Linacoustic HP is specifically designed for lining sheet metal ducts in air conditioning, heating and ventilating systems. •Install vertical flex duct hangers at least every 6 feet (1. and Air-Conditioning Engineers (ASHRAE) approved ANSI/AMCA Standard ANSI/ASHRAE Standard , Laboratory Methods of Testing Fans for. Below a certain Reynolds number (critical Reynolds number), the fall-off of the heat transfer coefficient curve was. Maximum friction rate (to limit fan power). •Use flex duct supports that are ridged and at 1. has an air-side economizer with a motorized damper already installed in the OSA duct, the cost of adding CO 2 sensors will be close to $500. The conventional system sized this way will need a 22 in. Pure earth atmosphere, at 70°F with 50% relative humidity and devoid of smoke particles, mold spores, air-bourne pathogens, plant pollen, respirable dust and with oxygen and carbon dioxide levels that remain constant despite our breathing - would be ideal, but terribly impractical. And better, from Annex A (Explanatory Material): A. At point B in Figure 1, the air velocity is uniform across the duct and low compared to the outlet velocity (point A). The 922 velocity and air flow calculations are based on standard air at 29. The purpose of air conditioning ductwork is to deliver air from the fan to the diffusers which distribute the air to the room. 1-2004) Includes ANSI/ASHRAE Addenda listed in Appendix I www. That point is called the air flows terminal velocity. (AMCA) Standard 201 •Proper Straight Duct Length (Effective Length) For Uniform Velocity Profile •Inline & Centrifugal Fans –2. In this study, minimum and maximum air velocity limits are set to 600 fpm. From rectangular to round, from in-duct to flange, and from damper depth to face velocity. 3 of ASHRAE 62. galvanized steel enclosure frame. The outdoor air flow rate required to meet the ventilation requirements of ASHRAE Standard 62. of water, ρ is air density in lb/ft3, and gc is the gravitational acceleration constant, 32. This 4,000 ft/min results in 1 in of velocity pressure, which is sufficient to offset duct friction losses in a typical duct system. The rigorous testing procedure undertaken resulted in a 34% reduc- tion in air infiltration. In the "Size by Airflow" mode, you can specify the total airflow in CFM (…. Clean Room Make-up Air Units Outside air make‐up AHU design with complete temperature and humidity control. The “ASHRAE HVAC Duct Sizer” application designed by Carmel Software Corporation for ASHRAE, allows the user to quickly size one HVAC duct run or a range of duct sizes using the constant friction method. Toolbox column “VAV Box Duct Design” in the July 2015 ASHRAE Journal addresses sizing of the inlets and outlets to VAV boxes. Unico high velocity air handlers average a 25 to 30 degree temperature drop. 28 ASHRAE Journal ashrae. 2011 ASHRAE Handbook—HVAC. A sealant is then applied. 4°C) External: 150°F (66°C) Maximum Air Velocity UL 181/ULC S110 Erosion Test. Use top curve (below 80°F inlet air). 1-2010 as that portion of supply air that is outdoor air plus any recirculated air that has been treated for the purpose of maintaining indoor air quality (IAQ). General Exhaust must remove. In other words, if we have 100 cubic feet per minute (cfm) of air flow in the larger piece of duct below, then the air must still flowing at 100 cfm when. Throw data is based on supply air and room air being at isothermal conditions. ASHRAE Standard 55-2010 mandates a maximum 5. Maximum face velocity (FPM; feet per minute face velocity): 1. main plenum location shall ensure that the 2” flex duct length is minimized with a maximum run length of 25 ft. 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. adpi - air diffusion performance index Holyoake took on the responsibility to verity the ADP' design rating at our development and testing facility in Queensland. 1 consider 0. Low pressure/low velocity: 2"-WG positive or negative static pressure and velocities less than 2,500 fpm. Qatar Oryx Chapter, ASHRAE QATAR Doha, QATAR ASHRAE Storage. DETECTOR INSTALLATION [5. These studies indicate that the leakage rates appear greater than the maximum permitted leakage rates. The Preeva REH design. indoor air quality a complex, multifaceted problem. Air velocity limitation sets the boundaries for duct sizes. ANSI/ASHRAE Standard 62-2001 Ventilation for Acceptable Indoor Air Quality Approved by the ASHRAE Standards Committee on June 28, 2003; by the ASHRAE Board of Directors on July 3, 2003; and by the American National Standards Institute on January 8, 2004. 4 of the standard. I have read that about <=400 fpm is good for residentail design. 0% cumulative frequency of occurrence for indicated month, °C; mean coincident wet-bulb temperature, °C. 28 Minimum Rated Final Resistance (Inches W. Air Distribution - Service Life Data per Above Criteria [Total # of Matching Buildings: 344] [Total Pieces of Equipment found: 27750] * Equipment with no units, not shown. The stiffness or flexural rigidity is the product of Young's Modulus of Elasticity (E) and the Moment of Inertia (I), as determined in accordance with NAIMA AHC-100-74 (REF, ASTM D 1037). Duct Width (In. Air Cleaners. 2 of (ANSI/)ASHRAE Standard 62(. Operating Temperature Limit: 250°F (121°C) Maximum Air Velocity: 6,000 fpm (30. 5 m/sec) Water vapor sorption ASTM C1104 <3% by weight at 120°F (49°C), 95% R. outdoor air to dilute contaminants that are generated inside the building (by people, equipment, processes, or furnishings). for seated, 6 ft. Maybe you already know that one reason it’s important to change them out is that when dust and dirt accumulates on the filter, it restricts airflow to your HVAC system. Zone 2 The jet begins mixing with air in the room. 1: Energy Standard for Buildings Except Low-Rise Residential Buildings and the International Energy Conservation Code (IECC) are the major energy design standards for new buildings in the United States. duct system traversing as defined in the ASHRAE Handbook of Fundamentals, AMCA publication #203, as well as the Industrial Ventilation Handbook. * include fittings in the Duct TEL. HVAC equipment operated at higher air speeds than those for which it was designed loses efficiency and for filters, will begin to bypass rather than remove particles from building air. A new section is created when one of these factors change; Duct Sizing Examples. To gain some insight into this, lets consider a 12” square elbow with a 12” centerline radius (i. + grease filters/extractor in. Also determine the diameter of the duct if the air velocity is not to exceed 4 m/s. Klepper, W. Design of Flexible-duct Junction Boxes Current Standards • ASHRAE 2012 HVAC Systems and Equipment, Box Plenum Systems Using Flexible Duct - Constrains Box Width to 2-3x Entrance Width - Constrains Box Length to 2 x Box Width - Flat Pressure Loss = 0. Recommended design velocity for supply air in the main duct should not exceed 1200 fpm and of return air 600 fpm. The national consensus standard for outside air ventilation is ASHRAE Standard 62. " A conservative interpretation of Standard 62. 1* The air velocity through any duct shall be not less than 152. 0 Minimum MERV Rating 6 Style 2 - Ring and link, three-ply panel filter with internal wire frame 1. within the duct section = Flow velocity (mis) = Air density (m3/kg) = Energy demand cost (cost/kW) = Unit electrical energy cost (cost/kWh) About the Authors Robert W. When you put the ducts in an unconditioned attic and have the minimum insulation allowed, you want to move the air at a higher velocity, pushing it up near the maximum recommended by ACCA Manual D, 900 feet per minute (fpm) for supply ducts and 700 fpm for return ducts. This zone is approximately be-tween 68 and 75°F for heating, between 73 and 80°F for cooling, and between 40 and 60% relative humidity. The functional testing of ventilation and air conditioning systems includes monitoring the flow speed in ventilation ducts. The nominal condenser airflow is 2000 CFM. fume hood exhaust. Operating Temperature Limit: 250°F (121°C) Maximum Air Velocity: 5,000 fpm (25. (Q) Duct Cross-Sectional Area of the section. • Type 1 dryers between +0. FA, January, 2013. 1 requires that ve ntilation be increased by 25% when heating, if the above rules are not followed. Additional inputs can be used to monitor discharge air or other field inputs. This module is fully integrated with Right-Draw ® and all load calculation modules for accurately sized ducts. (25 Pa, whether or not the air handler is used for ventilation. 05 Due to a policy of continuous development and improvement the right is reserved to supply products which may differ. Set the return air trunk minimum velocity to 250 ft/min and the maximum velocity to 550 ft/min. Face velocity-velocity on the front of an enclosing hood. Size supply branch ducts for a maximum duct velocity of 1500 fpm. ft/min Feet per minute. Outside air from roof hood Direct‐drive fan array (4 fans) (535 CFM/BHP), N+1 8‐row, 8 FPI cooling coil sized for 400 FPM face velocity and 0. cooling CFM and air velocity. 1: Ventilation for Acceptable Indoor Air Quality Calculate the system-level outdoor air intake flow A VAV system is a multiple-zone recirculating system, so the outdoor air intake flow is determined in accordance with Sections 6. Marshall, "Noise Control in Music Teaching Facilities," Noise Control Engineering Journal, September-October 1980,p. However, due to the ability to displace oxygen, Addendum L to ASHRAE Standard 34-2010 has established the maximum RCL to 26 lbs/1000 ft3of room volume for occupied spaces. Because the. Ductwork for fume hood exhaust systems shall be welded 316 stainless steel duct, pitched back to the hood. The faster the air exits the face, the farther the air will travel into the room. 75 m/s face velocity. Because the design air volume is now trying to be pulled through a smaller cross sectional area, the air velocity would have to increase through that section of duct to maintain the design flow. per ft (42 mm per m). • No condensation issues. Round Duct Equivelent of Rectangular Duct: First Side of Rectangular Duct (in. over the operating range of the terminal unit. "The volume of outdoor air required to meet the ventilation requirements of Section 6. The variation between the temperature of the buildings in summer and the air in the cold air duct is 50 to 55. 5, Air-to-Air Energy Recovery. Last take-off run to be located 12" - 18" from end. Then size of rectangular duct is calculated considering minimum aspect ratio. Atmospheric pressure outside. ANSI/ASHRAE Standard 185. At point B in Figure 1, the air velocity is uniform across the duct and low compared to the outlet velocity (point A). V = 4005 x √ΔP) V = 4005 x √0. max heating coil velocity - hot water coil: Max 550 fpm Electric Filter - not rated by ASHRAE - remove large particles and contaminants out of indoor air. 9 to correct for the higher velocity at the center. fresh air inlet duct of the air handling units. Related Topics. Based on formulas in ASHRAE Fundamentals - Duct. ACCA Manual D Recommended Velocity (FPM) Supply Side Return Side Recommended Maximum RecommendedMaximum. Indoor Air Quality ANSI/ASHRAE Standard 62. The ASHRAE Filter is a HEPA type filter, available in Merv 14, Merv 13 and Merv 11. 35 air change per hour (ASHRAE, Standard 62, 1989). per 100 ft (2. Throw data is based on supply air and room air being at isothermal conditions. Heater air velocity = 1000 CFM/2 sq. org See Appendix I for approval dates by the ASHRAE Standards Committee, the ASHRAE Board of Directors, and the American National Standards Institute. V = velocity of air in meters per second. Each variable air volume hood shall maintain an average face velocity of 90-110 fpm at the maximum allowed hood opening. The ASHRAE HVAC Duct Sizer application allows you to quickly size one HVAC duct run or a range of duct sizes using the constant friction method.