ACCA Updates Manual D Residential Duct Systems
Principle changes are outlined
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 (VAV) 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, and
- N4: Fitting Equivalent Lengths.
- The informative sections and appendices that follow contain additional explanation, details, and examples on the normative requirements:
- Updated and expanded 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; and
- 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.
Publication date: 4/4/2017