Submission of Manual-J Load Calculations Compliance Review

The multifamily developer is responsible for submitting Manual-J Load calculations that are compliant with Air Conditioning Contractors of America (ACCA) standards and compliant with EarthCraft standards for building envelope and whole-building ventilation. The multifamiy developer is also responsible for distributing all load calculation requirements to all project stakeholders, including the mechanical engineer.

The mechanical engineer or mechanical contractor will submit a Manual-J load calculation developed using current ACCA approved software for each unit type within the development which complies with all EarthCraft requirements listed below.  Once received, the EarthCraft Technical advisor EarthCraft will review the Manual-J for compliance and will report all compliance issues to the interested parties. The purpose of this review is to ensure all HVAC systems are compliant with EarthCraft and ACCA standards prior to purchase and/or installation of any equipment.

The developer shall submit these files for review early in the development process (but no later than at the Design Review) to avoid any issues arising from non-compliant load calculations and/or equipment selection.

EarthCraft is not responsible for the purchase of non-compliant systems or a developments failure to certify due to the installation of non-compliant systems.  EarthCraft is not responsible for compliance issues due to late submission of the Manual-J reports.

As mentioned in Step 1 below, if the project team is not using an ACCA approved software to complete the Load Calculation, the Professional Engineer must complete the Load Calculation Affidavit located on the website under Resources.

A complete list of ACCA approved software may be found here: https://www.acca.org/standards/approved-software

Criteria

Size and select all HVAC equipment in accordance with ACCA Manuals J and S. Load calculation must coordinate with accurate construction specifications and plans for the project as well as as-built conditions. 

1.    Complete load calculation with accredited ACCA Manual J 8th Edition Software or stamp by a Professional Engineer

Load calculation must be based on ACCA Manual J 8^th Edition Software. Software selected must be appropraite for the EarthCraft Multifamily property building design and construction characteristics. The following software programs are ACCA Manual J 8^th Edition compliant:

          - Wrightsoft Right-J8

          - Elite RHVAC

          - Adtek AccuLoads

          - Florida Solar Energy Center‘s EnergyGauge

          - Carmelsoft HVAC ResLoad-J

          - Avenir MJ8 Editions of HeatCAD and LoopCAD

          - Cool Calc Manual J

          - Conduit Tech

          - Amply Energy

                     https://www.acca.org/standards/approved-software

                                                  OR

Load calculation must be stamped by a Professional Engineer along with a signed "Professional Engineer Load Calculation Affidavit". This can be found on the EarthCraft website under Resources.

2.    Base on worst-case unit orientation

Load calculation must be based on worst-case unit orientation as constructed.

3.    Use 2021 ASHRAE Handbook of Fundamentals Climate Design Information for outdoor design temperatures

Design heating and cooling systems using the annual outdoor design conditions as defined in the 2021 ASHRAE Handbook of Fundamentals. 

          - The 99% design conditions must be used to size heating equipment

          - The 1% design conditions must be used to size cooling equipment

4.    Indoor temperatures 70°F for heating and 75°F for cooling

Design heating and cooling systems using indoor design temperatures of 70°F for heating and 75°F for cooling.

5.    Base building tightness on "tight", "semi-tight", or target tested air leakage

If using Simplified leakage, select "tight", "semi-tight", or software equivalent for whole house infiltration. If using calculated leakage, CFM50 equivalent leakage must be based on EarthCraft limits for air leakage.

6.    Use actual area, U-factor and SHGC for windows and doors, actual area and R-values of floors, walls and ceilings

Load calculation must be based on actual window, insulation and door specifications as installed.  Window, door, wall, floor and ceiling areas must be ±10% of actual areas as constructed.

7.    Base on ASHRAE 62.2-2010 ventilation loads

Load calculation must be based on ventilation system designed and installed to meet, at a minimum, the ASHRAE 62.2-2010 standards.  This includes the ventilation system type, location, design rate, and frequency and duration of each ventilation cycle.

8.    Select cooling and heating equipment using current ANSI/ACCA Manal S standard.

Cooling equipment selection, including heat pumps and air conditioners, must be between 90-115% of load calculation or the next available nomimal size unit.  Installed heat pumps in Climate Zone 4 must be within 125% of load calculation or the next available nominal size unit.

Use current Manual S limits for sizing two-stage or varable capacity equipment if selecting systems >115% of calculated loads.

Clarifications

The abridged edition of ACCA Manual J is not an acceptable methodology within the EarthCraft program.

If software allows for grades of duct tightness, chooses "extreme" or the equivalent term.