March 14, 2017
The Air Conditioning Contractors of America Educational Institute (ACCA-EI) Standards Task Team (STT) announces the release of an updated ANSI/ACCA 1 Manual D – 2016 (Residential Duct Systems).
The ANSI-recognized national standard for residential HVAC duct design positions contractors to properly design residential ducts for constant volume systems and zoned variable air volume systems, over a full range of duct construction materials.
The revised standard has been divided into two portions: normative and informative. The upfront normative sections contain the minimum requirements for conducting a residential duct system design. The informative sections and appendices that follow contain additional explanation, details, and examples on the normative requirements. The principle changes to Manual D – 2016 from the prior 2014 version are:
- The addition of four normative sections:
- N1: Normative Requirements for System Design,
- N2: Manual D Worksheets (and how to complete same),
- N3: Normative Tables,
- N4: Fitting Equivalent Lengths.
- The informative sections and appendices that follow contain additional explanation, details, and examples on the normative requirements:
- Updated and expanded Variable Air Volume (VAV) guidance, with detailed examples,
- Impacts of excess length, sag and compression in flexible ducts,
- New equivalent length values for flex duct junction boxes,
- Additional informative discussion regarding accessing of hand balancing dampers located in runout ducts,
- Additional discussion on system design impact when bypass dehumidifiers are added to an HVAC system,
- Other non-substantive revisions within the document for clarification or grammatical/editorial corrections.
Copies of ANSI/ACCA 1 Manual D Residential Duct Systems – Third Edition Version 2.5 - 2016 are available now at www.acca.org/store or by calling 888-290-2220.