{"id":3918,"date":"2014-05-30T09:29:45","date_gmt":"2014-05-30T13:29:45","guid":{"rendered":"http:\/\/www.constructionspecifier.com\/?p=3918"},"modified":"2017-01-13T15:43:25","modified_gmt":"2017-01-13T20:43:25","slug":"designing-masonry-buildings-to-the-2012-energy-code","status":"publish","type":"post","link":"https:\/\/www.constructionspecifier.com\/designing-masonry-buildings-to-the-2012-energy-code\/","title":{"rendered":"Designing masonry buildings to the 2012 Energy Code"},"content":{"rendered":"
\"All<\/a>
All images courtesy Mortar Net Solutions<\/em><\/figcaption><\/figure>\n

by Steven Fechino
\n<\/strong>The 2012 International Energy Conservation Code<\/em> (IECC<\/em>) will bring tremendous change to the way buildings are designed, constructed, and renovated. Several of the code\u2019s changes have already been implemented throughout the industry, with many of the currently specified systems and products meeting these new codes. However, there are also materials and assemblies that will need to evolve to remain compliant.<\/p>\n

For instance, HVAC systems will require improvements to the mechanical systems and ductwork. Window glazing is becoming more energy-efficient to meet ever-tightening performance criteria. Further, there is this author\u2019s focus\u2014the insulation requirements for masonry construction have been written to higher performance levels. There are many rumors about how the changes will limit the available products with which masonry structures can be built and designed. This article will address some of those rumors by providing simple explanations of the code and some helpful insight into how the industry is dealing with the changes on a positive level.<\/p>\n

\"This<\/a>
This diagram shows the elements of a cavity wall This particular assembly includes an insect barrier and mortar-dropping-collection device.<\/span><\/figcaption><\/figure>\n

<\/a>The 2012 energy code has been adopted state by state, and jurisdiction by jurisdiction, so the changes have not been applied uniformly across the country.1<\/sup><\/a><\/a> Nevertheless, the updated IECC <\/em>is important to all design\/construction professionals, because it is a positive step toward reducing the country\u2019s energy consumption through the design, construction, and operation of more efficient structures. It is important to adapt to these changes as soon as possible, since all regions will likely be affected by the code sooner or later. Preparing now will make the eventual transition to the new energy standards much easier.<\/p>\n

CMUs and continuous insulation<\/strong>
\nThe prescriptive energy code for the masonry industry is based primarily on the requirement for continuous insulation (ci) within the wall envelope. This becomes an issue when one looks at the standard concrete masonry unit (CMU)\u2014the cross-webs prevent continuous insulation within the block because they allow thermal bridging. By reducing the cross-web dimension, thermal bridging is reduced and the thermal efficiency of the unit is increased. However, this, in itself, is not the solution to code compliance. It is important to look at all the compliance criteria.<\/p>\n

In some cases, a CMU assembly\u2019s mass and resistance to heat transfer (i.e.<\/em> R-value) are all that is necessary to meet the code, but only in warmer climates. Differing temperature conditions means various types of insulation are used in designing the many single-wythe and cavity wall systems specified across the country. Rigid insulation, foam inserts, dry loose fill, injected foam, spray-on foam, and proprietary block design round out the field of techniques for increasing R-value, with typical gains of 5 to 25.<\/p>\n

An important factor for determining energy efficiency of a CMU wall is the envelope\u2019s design, specifications, and the materials making up the assembly\u2014various concrete masonry manufacturers will have similar, but ultimately different, mixes. This is one factor that can change a CMU wall\u2019s R-value and the thermal mass performance of otherwise similar envelopes. (For more, see \u201cThermal Mass Basics.\u201d)<\/p>\n

<\/a>Other factors include geographical climate history, insulation specifications (within either the CMU or the cavity), and the actual cross-section of the masonry units comprising the wall design. For assistance with this, the National Concrete Masonry Association\u2019s (NCMA\u2019s) TEK 6-2B, R-Values and U-Factors of Single-wythe Concrete Masonry Walls<\/em>, discusses thermal performance of a CMU wall and its thermal properties based on material properties.2<\/sup><\/a><\/p>\n

\"This<\/a>
This church was built with masonry cavity<\/span>
walls and brick veneer.<\/span> An important factor<\/span>
for determining such a<\/span> wall\u2019s energy efficiency<\/span>
is the envelope\u2019s design, <\/span>specifications, and the<\/span> materials making up<\/span> the assembly.<\/span><\/figcaption><\/figure>\n

The three paths to compliance<\/strong>
\nIt is important to clear up the rumor that all masonry walls will require continuous insulation in order to meet the new standards. There are many ways a designer can achieve compliance using complete building systems to meet the new IECC<\/em> requirements rather than relying solely on continuous insulation.<\/p>\n

Right now, there are three methods available for determining code compliance, and many of the current masonry designs will show acceptable numbers in at least one of them. These methods are:<\/p>\n