| Voluntary programs such as Leadership in Energy and Environmental Design (LEED) have joined with new building code requirements to reinforce holistic approaches to the entire building process. The new LEED v4 program is a significant revision from the previous 2009 edition. It calls for specific performances that can be met with concrete masonry units (CMUs).
Increased energy efficiency
In LEED v4, buildings must be at least five percent better than American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 90.1-2010, Energy Standard for Buildings Except Low-rise Residential Buildings, with whole-building energy simulation as the preferred compliance path. Masonry can add increased R-values to energy performance.
Thermal mass
Thermal mass, as found in masonry products, absorbs energy slowly and stores it for longer periods. This reduces indoor temperature swings and often leads to a reduction in the size of mechanical heating and cooling systems.
Material ingredients matter
Three entirely new credits in the LEED v4 Materials and Resources (MR) section require documentation of building product raw materials and their effects on the environment, such as material ingredient reporting, health product declarations (HPDs), and environmental product declarations (EPDs). Several concrete masonry unit (CMU) manufacturers have published such information on their products.
Product sourcing
Other new MR credits include sourcing of raw materials and a new take on regional materials that eliminates the standalone credit and instead adds weight to products sourced within 160 km (100 mi) of the project site. Manufactured masonry can often be sourced within this distance.
Consideration of building life cycle added
Expanded credits include reusing existing buildings and a new credit on performing a whole-building life cycle assessment (LCA). Masonry buildings provide a long life and durability that are essential for reuse.
Acoustic performance
LEED v4 now includes a prerequisite for minimum acoustic performance in schools and a credit for acoustic performance in most other versions of the rating system. Manufactured masonry can enhance acoustical performance, evidenced by its recent use in public theaters.
Christine A. Subasic, PE, LEED AP, is a consulting architectural engineer specializing in masonry and sustainable design. She has provided technical support services, standards development, and seminars for the masonry industry for more than 25 years. |
