HVAC ASHRAE 62.1-2013 Online Help

The HVAC ASHRAE 62.1-2013 app for the iPhone allows you to perform comprehensive minimum ventilation calculations for a wide variety of commercial buildings based upon Standards 62.1-2007 and 2010/2013.

The ASHRAE 62.1 application allows you to quickly perform comprehensive minimum ventilation calculations for a wide variety of commercial buildings based upon the ASHRAE Standards 62.1-2007 and 2010/2013. This app is based upon the "62MZCalc.xls" Excel spreadsheet that accompanies each copy of the ASHRAE Standards 62.1-2007 and 2010/2013.

You can do pretty much do everything in this app that you can do in the Excel spreadsheet, in addition to creating multi-system projects and emailing results so you can perform further calculations. This help file details how to use this application on the Apple iPhone.

Quick Start

The following is a list of hints and suggestions to quickly get started using the ASHRAE 62.1-2013 application:
  1. This updated version of the app allows you to perform calculations for both the 2007 and 2010/2013 versions of the ASHRAE 62.1 Standard. You can select the version by individual project, and it will either hide or display the appropriate inputs and results according to the selected version.
  2. The app comes preinstalled with 1 sample project and a "default" project. The sample project was based upon an actual LEED-certified project which involved calculating minimum ventilation requirements per ASHRAE 62.1. The "default" project is the base project used to create all new projects. You can edit this project at any time and assign values more appropriate to the jobs that you perform.
  3. To create a new project, select the "+" button in the upper right-hand corner of the first screen that appears when you start the app. You can input a new project name or select an existing project to copy from.
  4. You will notice that a number of system and zone inputs are displayed in a "maroon" color. These signify inputs that are calculated based upon other input selections but may be overridden if appropriate. For example, the zone population is automatically calculated based upon the space type and the floor area of that space. You can choose to override this value by manually inputting a value into the text box or sliding the indicator along the slider control located just below it. To restore the auto-calculation functionality of the input, just enter 0 or erase the value in the input box. If you want to enter a value of 0 for this input, slide the indicator along the slider control all the way to the left to 0. This functionality applies to all inputs that are auto-calculated.

Overview

When you first open the ASHRAE 62.1 application, you will see 3 tabs at the bottom of your screen:
  1. The "ASHRAE 62.1" tab is the first screen that appears when you start up the application and allows you to peform the ASHRAE 62.1 ventilation calculations.
  2. The "Global Settings" tab allows you to specify global settings such as whether to use IP (Imperial) or SI units. Please read the "Global Settings" section below for more details.
  3. The "Help" tab displays this help screen.

ASHRAE 62.1 Tab

This tab automatically appears when you first start the ASHRAE 62.1 application. It lists all of the projects that have been created so far. The following describes how to create, edit, and delete projects:
  1. Create a New Project: To create a new project, click the "+" button located in the upper right-hand corner of the screen. A new form will appear allowing you to enter a new project name. Also, you can copy from an existing project by pressing the button "Copy from existing project >>". After pressing this button, a list of all existing projects will appear allowing you to select from one. When you return to the "Add Project" screen, type in a new project name. If you do not copy from an existing project, type in the new project name and the "_Default Project" will be used as the basis for creating the new one (See "Template Projects" below for more information on the "_Default Project").
  2. Edit an Existing Project: To edit an existing project, select the project name with your finger and the next form will slide onto the screen allowing you to input information about the project.
  3. Delete an Existing Project: Swipe your finger across the name of the project that you wish to delete. A "delete" button will appear allowing you to press it to delete the project.
You will also notice that below each project name, the client name and client location (city, state, and zip code) display in smaller grey text.

Project Inputs
The following describes the overall project input information (Only the "Project Name" is mandatory):
  1. Project name: This is the name of the project that you originally inputted when you created the project. You can change the project name in this text box. To do so, tap your finger within the text box and the standard iPhone keyboard will pop up allowing you to type in a new name. This keyboard will appear anytime you tap your finger within any of the textboxes in this app.
  2. Project number: Input a project number if appropriate.
  3. Project date: The project date is automatically filled in with the date the project was created. You can override it.
  4. Project engineer: Input the name of the project engineer performing the ASHRAE 62.1 calculations.
  5. Client name: Input the client company or site name for which these calculations are being performed.
  6. Client building type: Input the type of building being analyzed for compliance with ASHRAE 62.1
  7. Client contact: Input the client contact name for which these calculations are being performed.
  8. Client address: Input the client company address.
  9. Client city, state, zip: Input the client company city, state, and zip code.
  10. ASHRAE 62.1 version: This selector control allows to specify which version of the 62.1 Standard (2007 or 2010/2013) will be used to calculate the minimum ventilation requirements. Depending upon the version you select, it will update the inputs and results in the screens that follow. (Please note: The 2010 and 2013 versions of the Standard are similar in terms of calculations. However, the 2013 version includes a couple of additional space types.)
System List: Select this option to display the list of systems associated with the current project. The number of systems that have been created so far are displayed in this cell (i.e. - "Qty: 2").
Email Project: Select this option to email the current project information (including all inputs and results). See below for more information.

Template (or Default) Project
The ASHRAE 62.1 app includes a default project (called "_Default Project"). This project contains 1 default system and 1 default zone (area). This default project is used as the basis for all new projects that are created (except for those that are copied from an existing project). You can edit all of the data in this default project by selecting the "_Default Project" and editing as you would any normal project. Please note that you cannot add new systems and zones within this default project. Within each project is fa system called "_Default System". This system is used as the basis for all new systems that are created (except for those that are copied from existing systems). Within the "_Default System" is a zone called "_Default Zone". This zone is used as the basis for all new zones that are created (except for those that are copied from existing zones).

System List
The system list form displays a list of all of the systems associated with the current project. A system is defined as a group of zones (or rooms) with a common air handling unit. You can define different systems any way you want. For example, you can create a "summer" system with summer airflows specified and a "winter" system with winter airflows specified. The following describes how to create, edit, and delete systems:
  1. Create a New System: To create a new system, click the "+" button located in the upper right-hand corner of the screen. A new form will appear allowing you to enter a new system name. Also, you can copy from an existing system by pressing the button "Copy from existing system >>". After pressing this button, a list of all existing systems (within the current project) will appear allowing you to select from one. When you return to the "Add System" screen, type in a new system name. If you do not copy from an existing system, type in the new system name and the "_Default System" from the "_Default Project" will be used as the basis for creating the new one (See "Template Project" explanation above for more information).
  2. Edit an Existing Systerm: To edit an existing system, select the system name with your finger and the next form will slide onto the screen allowing you to input information about the system (See the "System Inputs and Results" section below for more details).
  3. Delete an Existing System: Swipe your finger across the name of the system that you wish to delete. A "delete" button will appear allowing you to press it to delete the system and all the zones within the system.
You will also notice that below each system name, you are able to preview the system ventilation efficiency (Ev) and required system outside air quantity (CFM or L/s).

System Inputs and Results
The following describes all of the system inputs and results. There are 2 "pages" of inputs and 1 "page" of results. To navigate from one page to the next, simply swipe your finger to the left or right on any open area of the screen.

Page 1 (Inputs 1)
The following describes inputs for the first page:
  1. System Name: This is the name of the system that you originally inputted when you created the system. You can change the system name in this text box.
  2. System Floor Area - As (SqFt or SqM): This is a calculated value that can also be overridden. It represents the total floor area served by the system by adding up the floor areas of all zones located within the system. If the color of the number in the text box is maroon, this means that the calculated value is displayed. If you override the value by manually inputting a value (or sliding the slider indicator locatd below this input box), the color of the number turns black. To restore the calculated value, erase the value in the textbox and exit or enter the value of 0. The calculated value will display in maroon again.
    A slider control is located underneath the floor area text box. By sliding the indicator along the slider control, you can increase or decrease the floor area value and observe the updated results at the bottom of the screen. To update the step or maximum values on the slider, go to the "Settings" form discussed below.
  3. # of people served by system - Ps: This value represents the total number of people served by the system. The total quantity of people entered in all the zones for this system is calculated here as a default. If the color of the number in the text box is maroon, this means that the calculated value is displayed. If you override the value by manually inputting a value (or sliding the slider indicator), the color of the number turns black. To restore the calculated value, erase the value in the textbox and exit or enter the value of 0. The calculated value will display in maroon again. You can also use the slider control to increase and decrease the people quantity value.
    Diversity may be and usually is taken into account (not all zones will be simultaneously occupied). The diversity factor (discussed below) will be multiplied by the sum of zone occupants, but it has no effect if Ps has been manually overridden. For example, if the total of all people for all zones in a system is 6, but the diversity factor is 50%, the calculated value for this input is 3 (6 x 0.5).
  4. System supply fan airflow - Vpsd (CFM or L/s): This value represents the design system primary airflow rate supplied to all zones served by the system from the air handling unit at which the outdoor air intake is located. For VAV systems, Vpsd will generally include zone load diversity. For dual fan dual duct systems with outdoor air only supplied to the cooling fan, Vpsd is the cooling fan design airflow rate; if outdoor air is supplied equally to the heating and cooling fans, enter the sum of the two fan airflow rates.
    If the color of the number in the text box is maroon, this means that the calculated value is displayed. If you override the value by manually inputting a number (or sliding the slider indicator), the color of the number turns black. To restore the calculated value, erase the value in the textbox and exit or enter the value of 0. The calculated value will display in maroon again. Like the inputs discussed above, you can also use the slider control to increase and decrease the air flow value.
Results
The results at the bottom of page 1 are the two most important results to engineers performing the ASHRAE 62.1 calculations: the system ventilation efficiency (Ev) and the outside air required for the system (Vot). These results instantly update when any of the input parameters discussed above are updated. These results are discussed in more detail in the "System Results" section below.

Zone List
Click the button located in this cell to display the list of zones associated with the system. The number of zones that have been created so far are displayed in this cell (i.e. - "Qty: 2").

Page 2 (Inputs 2)
The following describes inputs for the second page:
  1. People Diversity (%): Input the system-wide people diversity factor from 0 to 100%. This value is multiplied by the total number of people from all zones to derive a people diversity value. This represents that maximum number of people located in the system at any one time.
  2. Supply fan airflow diversity (%): This input only appears when calculating according to the 2010/2013 version of the ASHRAE 62.1 Standard. Input the system-wide airflow diversity factor from 0 to 100%. This value is multiplied by the total system airflow from all zones to derive a supply fan airflow diversity value. This represents that maximum supply airflow at any one time.
  3. % of design airflow analyzed - Ds (%): The percentage of the design airflow rate at the conditioned being analyzed. For the system, Ds is multiplied by Vpsd to get the ventilation system airflow rate Vps. For constant volume systems, Ds is 1.0 at both the system and zones. For VAV systems, the following apply:
    1. Cooling condition: Ds is typically 1.0 for the system.
    2. Heating condition: Ds will be much lower than 1.0 reflecting the reduction in airflow rate at each zone. If all zones have been entered into the spreadsheet, Ds can be determined explicitly as the sum of the zone primary airflow rates (Ep*Ds*Vddz). If not all zones have been entered, Ds for the system must be estimated. Ds for each zone is determined assuming the zone is in full heating mode.
  4. OA req'd/unit area - Ras (CFM/SqFt or L/s/SqM): This is a calculated value that represents a weighted average of all the zone outside air requirements per unit area (derived from the space type) taking into account the area for each zone. If the number in the textbox is maroon, it is a calculated value. You can override this value and the number will display in black. To have it display the calculated value again, erase the value or input 0.
  5. OA req'd/unit person - Rps (CFM/person or L/s/person): This is a calculated value that represents a weighted average of all the zone outside air requirements per person (derived from the space type) taking into account the number of people for each zone. If the number in the textbox is maroon, it is a calculated value. You can override this value and the number will display in black. To have it display the calculated value again, erase the value or input 0.
  6. % increase in Vbz over min: This input only appears when calculating according to the 2010/2013 version of the ASHRAE 62.1 Standard. This value increases breathing zone ventilation as a percentage over the minimum required by the standard. This may be appropriate for LEED EQ Credit 2 to meet minimum increased ventilation.
Results
The results at the bottom of page 2 are the two most important results to engineers performing the ASHRAE 62.1 calculations: the system ventilation efficiency (Ev) and the outside air required for the system (Vot). These results instantly update when any of the input parameters are updated. The results are discussed in more detail in the "System Results" section below.

Zone List
Click the button located in this cell to display the list of zones associated with the system. The number of zones that have been created so far are displayed in this cell (i.e. - "Qty: 2").

Page 3 (Additional Results)
The following describes calculated results on the third page.
  1. OA / unit floor area - Vot/As: This is the design outdoor air intake rate required for the system divided by the total system area.
  2. OA / person (w/diversity) - Vot/Ps: This is the design outdoor air intake rate required for the system divided by the total number of people in the system accounting for diversity.
  3. OA as % of primary supply air - Ypd: This is the ratio of the outdoor air (Vot) divided by the total supply air.
  4. Primary supply air to system - Vps: This is the design primary supply fan airflow rate (described above) multiplied by the percent of total design airflow rate at conditioned analyzed (Ds) for the system.
  5. Uncorrected OA req'd for system - Vou: This is the uncorrected outside air required for the system based upon the weighted average of all of the zone airflow per area and airflow per person rates.
  6. Uncorrected OA req'd as fract of SA - Xs: This value is equal to Vou/Vps. It represents the uncorrected outside air required as a fraction of the total primary supply air.
  7. OA req'd as fraction of SA - Y: This value is equal to Vot/Vps. It represents the outdoor air intake flow required to the system as a fraction of the total primary supply air. This differs from Xs in that it takes into account system ventilation efficiency.
  8. System Population / unit area: This is the total system population density, either per 1000SqFt or 100SqM.
  9. Airflow / unit area: This is the total design primary supply fan airflow rate per unit area (per square foot or per square meter).
Zone List
The zone list form displays a list of all of the zones associated with the current system. A zone is defined as a room or space in a building. Each zone can be assigned a "space" type which defines the ventilation characteristics of the space. The following describes how to create, edit, and delete zone:
  1. Create a New Zone: To create a new zone, click the "+" button located in the upper right-hand corner of the screen. A new form will appear allowing you to enter a new zone name. Also, you can copy from an existing zone by pressing the button "Copy from existing zone >>". After pressing this button, a list of all existing zones (within the same project, only) will appear allowing you to select from one. When you return to the "Add Zone" screen, type in a new zone name. If you do not copy from an existing zone, type in the new zone name and the "_Default Zone" from the "_Default System" will be used as the basis for creating the new one (See "Template Project" above for more information).
  2. Edit an Existing Zone: To edit an existing zone, select the zone name with your finger and the next form will slide onto the screen allowing you to input information about the zone (See the "Zone Inputs and Results" section below for more details).
  3. Delete an Existing Zone: Swipe your finger across the name of the zone that you wish to delete. A "delete" button will appear allowing you to press it to delete the zone.
You will also notice that below each zone name, you are able to preview the zone ventilation efficiency (Evz) and the inputted zone airflow supply quantity (CFM or L/s). Also, the "critical" zone is displayed in maroon text.

Zone Inputs and Results
The following describes the overall zone input and results information. There are 2 "pages" of inputs and 1 "page" of results. To navigate from one page to the next, simply swipe your finger to the left or right on any open area in the screen.

Page 1 (Inputs 1)
The following describes inputs for the first page:
  1. Zone Name: This is the name of the zone that you originally inputted when you created the zone. You can change the zone name in this text box.
  2. Space Type: Select anywhere in this cell to open a new form that displays a picker list of all of the ASHRAE 62.1 space types listed in Table 6.1 of the Standard. Depending upon the the space type chosen will determine the ventilation outdoor air flow rates per unit area and per person. The following is a list of all the space types:
    1. Art classroom
    2. Auditorium seating area
    3. Bank vaults/safe deposit
    4. Banks or bank lobbies
    5. Barbershop
    6. Barracks sleeping areas
    7. Bars, cocktail lounges
    8. Beauty and nail salons
    9. Bedroom/living room
    10. Booking/waiting
    11. Bowling alley (seating)
    12. Break rooms
    13. Cafeteria/fast-food dining
    14. Cell
    15. Classrooms (age 9 plus)
    16. Classrooms (ages 5 to 8)
    17. Coffee stations
    18. Coin-operated laundries
    19. Common corridors
    20. Computer (not printing)
    21. Freezer and refrigerated spaces (new for 62.1-2013)
    22. Computer lab
    23. Conference/meeting
    24. Corridors
    25. Courtrooms
    26. Daycare (through age 4)
    27. Daycare sickroom
    28. Dayroom
    29. Disco/dance floors
    30. Dwelling unit
    31. Electrical equipment rooms
    32. Elevator machine rooms
    33. Gambling casinos
    34. Game arcades
    35. General manufacturing (excludes heavy industrial/processes using chemicals)
    36. Guard stations
    37. Gym, sports arena (play area) - (new for 62.1-2013)
    38. Health club/aerobics room
    39. Health club/weight rooms
    40. Kitchen (cooking)
    41. Laundry rooms within dwelling units
    42. Laundry rooms, central
    43. Lecture classroom
    44. Lecture hall (fixed seats)
    45. Legislative chambers
    46. Libraries
    47. Lobbies
    48. Lobbies/prefunction
    49. Main entry lobbies
    50. Mall common areas
    51. Media center
    52. Multipurpose assembly
    53. Multi-use assembly
    54. Museums (children's)
    55. Museums/galleries
    56. Music/theater/dance
    57. Occupiable storage rooms for dry materials
    58. Office space
    59. Pet shops (animal areas)
    60. Pharmacy (prep. area)
    61. Photo studios
    62. Places of religious worship
    63. Reception areas
    64. Restaurant dining rooms
    65. Sales (except as below)
    66. Science laboratories
    67. Shipping/receiving
    68. Sorting, packing, light assembly
    69. Spectator areas
    70. Sports arena (play area)
    71. Stages, studios
    72. Storage rooms
    73. Supermarket
    74. Swimming (pool and deck)
    75. Telephone closets
    76. Telephone/data entry
    77. Transportation waiting
    78. University/college laboratories
    79. Warehouses
    80. Wood/metal shop

  3. Floor Area - Az (SqFt or SqM): This is a manual input that represents the zone occupiable floor area. You can either input a value into the text box or slide the indicator along the slider control to increase or decrease the floor area value.
  4. Zone Population - Pz: This is either a calculated or manually inputted value. By default it is calculated according to the selected space type and the floor area. The space type determines the population density per 1000SqFt, and it is multiplied by the zone area to get the total number of people. When this value is calculated, the result will display in maroon. You can override the value by manually inputting the number of people, either by inputting the value into the text box or sliding the indicator along the slider control located below the text box. The text will display in black if it is an overridden. To return to the calculated value, either input a value of 0 into the text box or erase the value and exit the text box.
  5. Design total supply to zone - Vdzd (CFM or L/s): This is the design total rate of air supplied to the space including primary air (air from the AHU that has the outdoor air intake) and air transferred or recirculated from other spaces. Examples of transfer air include: air induced from adjacent spaces with an exhaust fan or induction terminal unit, air supplied by a terminal fan (e.g. fan-powered mixing box), or air supplied by the heating fan of a dual duct system. You can manually input a value into the text box or slide the indicator along the slider control to increase or decrease the air flow rate.
  6. The next input below the "Design total supply to zone" input can be one of two types depending upon the setting specified in the "Additional Settings" form discussed below:
    1. Primary air fraction of supply air - Ep (%): This is the ratio of Vpz to Vdz, and is a percentage value ranging from 0 to 100%. Vpz is the primary airflow supplied to the zone from the air handling unit at which the outdoor air intake is located. It does not include air transferred or air recirculated to the zone by other means. For a single duct system, this value is 100%. For a fan-powered mixing box system, Vpz is the supply air rate through the VAV damper but does not include the air supplied to the space by the terminal fan that is drawn from the return air plenum. For a dual fan dual duct terminal unit, Vpz is the cold duct air but does not include air supplied by the heating fan.
    2. Primary airflow to zone - Vpz (CFM or L/s): This is the primary airflow supplied to the zone from the air handling unit at which the outdoor air intake is located. It does not include air transferred or air recirculated to the zone by other means. For a single duct system, this value is equal to Vdzd. For a fan-powered mixing box system, Vpz is the supply air rate through the VAV damper but does not include the air supplied to the space by the terminal fan that is drawn from the return air plenum. For a dual fan dual duct terminal unit, Vpz is the cold duct air but does not include air supplied by the heating fan.
Results
The results at the bottom of page 1 are the most important results to engineers performing the ASHRAE 62.1 calculations:
  1. Zone ventilation efficiency - Evz: This is the calculated zone ventilation efficiency. The minimum of all of the zone ventilation efficiencies for a system is used as the system ventilation efficiency.
  2. Critical zone: If the current zone is the minimum zone ventilation efficiency, it is a critical zone and its Evz value is the system Ev value.
  3. System ventilation efficieny - Ev: This is the system ventilation efficiency that is equal to the minimum of all zone ventilation efficiencies for that system.
  4. OA required for system - Vot: This is the minimum outdoor air required for the system to satisfy the ASHRAE 62.1 Standard requirements.
These results instantly update when any of the input parameters are updated.

Page 2 (Inputs 2)
To display this page, simply swipe the screen to the left. This page contains additional zone-related inputs.
  1. Unit type for secondary zone airflow: Select this cell to display a new form with a picker control that allows you to select from the following:
    1. ITU: Induction terminal unit, such as a series or parallel fan-powered mixing box or system-powered induction unit, which can supply air to the zone from a ceiling return air plenum or from another ventilated space.
    2. DFDD: Dual fan dual duct system, which in addition to the primary ventilation cooling fan includes a parallel heating fan that can supply recirculated air to the zone. Selecting this option hides the "Recirculated air % - Er" input since this value is not used in the calcs for this option.
    3. TF: Transfer fan, which is a fan that supplies or induces transfer air into the room from another ventilated space.
    4. NONE: If none of these apply (such as single duct systems or single fan dual duct systems), select this option. Selecting this option hides both the "Recirculated air % (Er)" and the "Primary air fraction of supply air - Ep" inputs since these values are not used in the calcs for this option.
  2. Recirculated air percentage - Er (%): The percentage of secondary recirculated air supplied to the zone that is representative of average system return air rather than air directly recirculated from the zone. This is probably the most difficult variable to understand and to determine. For systems that fully mix the return air before recirculating it, such as dual fan/dual duct systems, Er is 100%. For systems with local recirculation fans such as fan-powered boxes or local transfer fans, Er is between 0 and 100%. Take for example a fan-powered mixing box. Er will be equal to 100% if the fan-powered box intake is located near the main air handler return air opening to the return air plenum, i.e. the return air to the fan-powered box is equal in quality to the return air that is going through the primary air handler. Er would be equal to 0 if the fan-powered box inlet were ducted directly to the zone it served, i.e. the quality of the air to the fan-powered box is equal to that in the zone served. In this case, the recirculated air provides no ventilation benefit. Most plenum mounted fan-powered box applications will be well between these extremes.
  3. Percent of total design airflow - Ds (%): This is the percentage of the design airflow rate at the conditioned being analyzed. For each zone, Ds is multiplied by Vdzd to get the zone total supply air rate Vdz. For constant volume systems, Ds is 100% at both the system and zone level. For VAV systems, the following applies:
    1. Cooling condition. Ds for is typically 100% for the system. For series fan-powered mixing boxes, Ds is 100% for all zones. For other systems in non-critical zones, Ds is either 100% or slighly less to reflect load diversity. For the critical zone(s) Ds will typically be determined based on the zone minimum airflow rate setpoint, although it may be higher to reflect the lowest zone load that can be expected when the space is fully occupied.
    2. Heating condition. Ds will be much lower than 100% reflecting the reduction in airflow rate at each zone. If all zones have been entered into the spreadsheet, Ds can be determined explicitly as the sum of the zone primary airflow rates (Ep*Ds*Vddz). If not all zones have been entered, Ds for the system must be estimated. Ds for each zone is determined assuming the zone is in full heating mode.
  4. Air distribution type: Select this cell to display a form that displays a picker control that contains a list of various air distribution configurations. Based upon the selection you make here will determine the the value of Ez that is described below. The following is a list of the air distribution configurations and the related Ez values:

    Code Ez Explanation - Ceiling Supply
    Custom -- Air change effectiveness determined in accordance with ASHRAE Standard 129
    CS 1.0 Ceiling supply of cool air
    CSCRH 1.0 Ceiling supply of warm air 15 deg. F or more above space temperature and ceiling return
    CSCRW 1.0 Ceiling supply of warm air less than 15 deg. F above space temperature and ceiling return provided that the 150 fpm supply air jet reaches to within 4.5 ft of floor level. Note: For lower velocity supply air, Ez = 0.8.
    CSFR 1.0 Ceiling supply of warm air and floor return.
    FSCR 1.0 Floor supply of cool air and ceiling return provided that the vertical throw is greater than 50 fpm (0.25 m/s) at a height of 4.5 ft or more above the floor.
    FSCR LV 1.2 Floor supply of cool air and ceiling return, provided low velocity displacement ventilation achieves unidirectional flow and thermal stratification, or underfloor air distribution systems where the vertical throw is less than or equal to 50 fpm (0.25 m/s) at a height of 4.5 ft (1.4 m) above the floor
    FSCRW 0.7 Floor supply of warm air and ceiling return
    FSFR 1.0 Floor supply of warm air and floor return
    MUEX 0.5 Makeup supply drawn in near to the exhaust and/or return location
    MU--EX 0.8 Makeup supply drawn in on the opposite side of the room from the exhaust and/or return

  5. Zone air distribution effectiveness - Ez: This is the zone air distribution effectiveness. Depending upon the air distribution type selected above will determine the value filled in here. You can override this value either by manually inputting a value in the text box or sliding the indicator along the slider control.
Results
The results at the bottom of page 2 are the most important results to engineers performing the ASHRAE 62.1 calculations:
  1. Zone ventilation efficiency - Evz: This is the calculated zone ventilation efficiency. The minimum of all of the zone ventilation efficiencies for a system is used as the system ventilation efficiency.
  2. Critical zone: If the current zone is the minimum zone ventilation efficiency, it is a critical zone and its Evz value is the system Ev value.
  3. System ventilation efficieny - Ev: This is the system ventilation efficiency that is equal to the minimum of all zone ventilation efficiencies for that system.
  4. OA required for system - Vot: This is the minimum outdoor air required for the system to satisfy the ASHRAE 62.1 Standard requirements.
These results instantly update when any of the input parameters are updated.

Page 3 (Additional Results)
To display this page, simply swipe the screen to the left. This page contains additional zone results (no inputs):
  1. OA rate/unit area for zone - Raz: This is the airflow per unit area from Table 6-1 for the selected space type.
  2. OA rate/unit person - Rpz: This is the airflow per person from Table 6-1 for the selected space type.
  3. Total supply air to zone - Vdz: This is the total supply air to the zone at the condition being analyzed. This value is equal to the design total supply air to zone (Vdzd) multiplied by the percent of total design airflow rate (Ds).
  4. Unused OA req'd to breathing zone - Vbz: This is the unused outside air required to the breathing zone. It is equal to the room area times the OA rate/unit area plus the # of people times the OA rate/person.
  5. Unused OA req'd for zone - Voz: This is the unused outside air required for the zone. It is equal to Vbz (described above) divided by zone air distribution effectiveness value (Ez).
  6. Fraction of zone supply not recirculated - Fa: This is the fraction of zone supply not recirculated. It is calculated from a combination of primary air fraction of supply air (Ep) and local recirculated air % (Er).
  7. Fraction of zone supply mixed air - Fb: This is the fraction of zone supply mixed air. It is equal to the primary air fraction of supply air (Ep).
  8. Fraction of zone OA not recirculated - Fc: This is the fraction of zone outdoor air not recirculated. It is calculated from a combination of primary air fraction of supply air (Ep), local recirculated air % (Er), and zone air distribution effectiveness (Ez).
  9. Unused OA frac. required in zone supply - Zd: This is equal to the unused outside air fraction required in supply air to zone. It is equal to the unused outside air required for zone (Voz) divided by the total supply air to zone (Vdz).

Additional Settings

The additional settings form is accessed by clicking the little "i" icon located in the upper right-hand corner of the project, system, and zone input forms. The following are a list of the inputs:
  1. Display Primary Air Fraction (Ep) or Airflow Supplied (Vpz): This selector allows you to select whether to input the primary air fraction (Ep) or airflow supplied (Vpz) on page 1 of the zone input form (see above). Vpz is the primary airflow supplied to the zone (in CFM or L/s) from the air handling unit at which the outdoor air intake is located. It does not include air transferred or air recirculated to the zone by other means. Ep is the primary air fraction of supply air (from 0 to 100%) at condition analyzed. For a single duct, the value of Ep is 100%. For a fan-powered mixing box system, Vpz is the supply air rate through the VAV damper but does not include the air supplied to the space by the terminal fan that is drawn from the return air plenum. For a dual fan dual duct terminal unit, Vpz is the cold duct air but does not include air supplied by the heating fan. Vpz = Ep x Vdzd.
  2. Max system airflow value (CFM or L/s): This input allows you to specify the maximum allowable system supply fan airflow value that is displayed on the slider control associated with the system airflow input.
  3. System airflow step value: This input allows you to specify the "step" value as you move the indicator along the system airflow slider control. For example, if you specify a value of "100", as you move the indicator to the left or right, the system airflow will decrease/increase by 100. If you specify 0, the increment is continuous.
  4. Max zone airflow value (CFM or L/s): This input allows you to specify the maximum allowable design supply airflow to the zone that is displayed on the slider control associated with the zone airflow input.
  5. Zone airflow step value: This input allows you to specify the "step" value as you move the indicator along the zone airflow slider control. For example, if you specify a value of "100", as you move the indicator to the left or right, the zone airflow will decrease/increase by 100. If you specify 0, the increment is continuous.
  6. Max system number of people: This input allows you to specify the maximum allowable number of people in the system that is displayed on the slider control associated with the input.
  7. System number of people step: This input allows you to specify the "step" value as you move the indicator along the system number of people slider control. For example, if you specify a value of "2", as you move the indicator to the left or right, the system number of people will decrease/increase by 2. If you specify 0, the increment is continuous.
  8. Max zone number of people: This input allows you to specify the maximum allowable number of people in the zone or space that is displayed on the slider control associated with the input.
  9. Zone number of people step: This input allows you to specify the "step" value as you move the indicator along the zone or space number of people slider control. For example, if you specify a value of "2", as you move the indicator to the left or right, the zone number of people will decrease/increase by 2. If you specify 0, the increment is continuous.
  10. Max system area (SqFt or SqM): This input allows you to specify the maximum allowable system area value that is displayed on the slider control associated with the input.
  11. System area step value: This input allows you to specify the "step" value as you move the indicator along the system area slider control. For example, if you specify a value of "100", as you move the indicator to the left or right, the system area will decrease/increase by 100. If you specify 0, the increment is continuous.
  12. Max zone area (SqFt or SqM): This input allows you to specify the maximum allowable zone area value that is displayed on the slider control associated with the input.
  13. Zone area step value: This input allows you to specify the "step" value as you move the indicator along the zone area slider control. For example, if you specify a value of "10", as you move the indicator to the left or right, the zone area will decrease/increase by 10. If you specify 0, the increment is continuous.
  14. Max air distrib. effectiveness - Ez: This input allows you to specify the maximum allowable air distribution effectiveness value that is displayed on the slider control associated with the input.
  15. Air distrib. effectiveness step value: This input allows you to specify the "step" value as you move the indicator along the air distribution effectiveness slider control. For example, if you specify a value of "0.1", as you move the indicator to the left or right, the zone area will decrease/increase by 0.1. If you specify 0, the increment is continuous.

Global Settings Tab

This form can be accessed by selecting the "Global Settings" tab on the home-page screen that first appears when you start the HVAC Duct Sizer application. The following is an explanation of each of the inputs:
  1. Units: This selector allows you to specify whether to display all values in IP (Imperial or English) or SI (Metric) units. When you return to the main input form, all values will reflect the new units.
  2. Digit Group Separator (Thousands Separator): This selector allows you to specify whether a thousands separator (ie - a comma - "1,000.00") should be utilized in all the input and output values. Specify "On" to include it, and "Off" to not include it. This option is important for international users of this application, where a comma is often not used as a digit separator.

Explanation of the ASHRAE 62.1 Formulas

The formulas used to calculate the ASHRAE 62.1 results are based upon equations from the ASHRAE Standard 62.1 (Both 2007 and 2010/2013 versions) and the accompanying work books and Excel spreadsheets.

Support Information

This software application was developed by Carmel Software Corporation exclusively for ASHRAE.

About Carmel Software

Commitment to HVAC, Apple iOS and Android

Stay Updated