Changes to important codes
ASTM C90-11 b and NFPA 285
Recent changes to important codes include:
ASTM C90-11 b – Hollow Loadbearing Concrete Masonry Units
This will allow cross web configurations to regulate by cross sectional section area, not by web thickness.
Reasons for paying attention to this code change are as follows:
- The change can increase R-values
- Structural characteristic and performance will not be changed
- In some cases, a reduction in cost may be achieved
- Creates a smaller demand for sustainable materials to produce the units
NFPA 285 - Standard Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load Bearing Wall Assemblies Containing Combustible Components 2012 EditionLanguage in the next building code will exempt the NFPA test when material flame indexes are met to published standards and airspaces that contain insulation are one inch (25 mm) or less.
The new language that was approved for inclusion in the next building code that exempts NFPA 285 testing:
Envelopes where rigid or spray applied insulation is encased by at least one inch (25 mm) of masonry, and there is no gap between the insulation and the masonry; or the insulation and the CMU are not separated by an airspace greater than one inch (25mm), and the insulation has an index for flame rate meeting requirements of ASTM E 84 or UL 723.
About the Author
Masonry, the official publication of the Mason Contractors Association of America, covers every aspect of the mason contractor profession - equipment and techniques, building codes and standards, business planning, promoting your business, legal issues and more. Read or subscribe to Masonry magazine at www.masonrymagazine.com.