HVAC Duct Construction Standards - Metal and Flexible 4th Edition is intended primarily for commercial and institutional duct construction and contains tables and details for constructing ductwork for ½-inch to 10-inch wg positive and negative pressures. This book improves upon previous editions with expanded pressure class tables, separate tables for TDC/TDF construction and expanded tables for round duct construction including 6-inch wg positive and negative pressure and sizes up to 96 inches. New in this edition is an engineering and design chapter to provide additional information to design professionals, double-wall construction details, new casing construction details and additional accessory items. The standard is applicable for construction using uncoated steel, galvanized and stainless steels and a limited range of aluminum ducts. This standard has been adopted in the International Mechanical Code. Includes soft metrics.