CHANTILLY, Va. - The Sheet Metal and Air Conditioning Contractors' National Association (SMACNA) has published the second edition of its Rectangular Industrial Duct Construction Standards.

The updated 446-page manual expands the scope of the 1980 version, updating original text to incorporate a revised theory of design, new materials, and more user-friendly tables, the association said.

The edition features new tables for stainless steels and aluminum, expanded chapters on materials, welding practices, and a guide specification. It covers the simple, low, or moderate temperature and pressure (or vacuum) indoor systems, as well as the more complex outdoor systems that operate at moderate to high temperature and pressure (or vacuum), and are subject to higher and more complex external loading.