Updated HVAC Duct Construction Standards
After thorough analysis, the revisions for SMACNA’s fourth edition HVAC Duct Construction Standards Metal & Flexible is now available to all SMACNA contractors.
According to Eli Howard, SMACNA’s executive director of technical services, the manuals, standards and guidelines are periodically reviewed by various committees (but never further than 5-10 years to comply with ANSI requirements), particularly after new technologies and methodologies have emerged. The following is a list of the most significant changes contractors should note from the previous version of the manual:
- ADDED INFORMATION ON SPRAY AND AEROSOLIZED DUCT SEALANTS
- ADDED TABLES FOR SPIRAL FLAT OVAL DUCT FOR POSITIVE AND NEGATIVE PRESSURE APPLICATIONS
- ADDED OPTIONS FOR INTERNAL SUPPORTS FOR SPIRAL FLAT OVAL DUCT
- UPDATED LINER REQUIREMENTS TO INCLUDE ON-FIBERGLASS LINER TYPES
- ADDED INFORMATION FOR LINED ROUND DUCT
- ADDED DETAILS TO BETTER ILLUSTRATE WHERE HANGERS ARE REQUIRED
- UPDATED REQUIREMENTS FOR FLEX DUCT HANGER SPACING AND HANGER WIDTH
- ADDED INFORMATION FOR SPIRAL FITTINGS
Although no changes were made to the root tables for rectangular duct, a few inconsistencies were fixed in the tables specifically addressing T25 a/b (TDC/TDF). Corrections included gage, reinforcement size and number of tie rods required. Minor corrections and clarifications were also made to the round tables.
To download your copy of the fourth edition standard, login to www.smacna.org and click on the Resources tab.