Concrete, Sustainability and Code Updates

Posted on October 15, 2020

Recent code updates address building safety, durability and sustainability. Architects often design with concrete to deliver code compliance. The longer life cycles and reduced maintenance of concrete structures enhance sustainability. They reduce the frequency of repairs and replacements, enhancing sustainability.

The International Building Code (IBC) is a model code. Each jurisdiction sets and enforces its own codes. IBC updates occur every three years. The most recent version is ICC IBC-2018.


Code Updates and Sustainability

Updated codes impact concrete construction in a variety of categories. Codes about energy performance and solar reflectance focus on sustainability. A graphic discusses the implications of certain building code updates.

Energy performance

Insulated concrete forms (ICFs) meet more stringent energy standards. They combine the benefits of continuous insulation and thermal mass. ICF projects often achieve energy savings of 40 percent or more.

Projects should exceed International Energy Conservation Code (IECC) standards by 20 percent. ICF construction meets such standards with ease.

Solar reflectance

Code updates also focus on cool roofs that better reflect the sun’s light and radiation. The 2018 code update specifies that solar reflectance meet one of two standards:

  • No less than a 3-yr aged solar reflectance of 0.55 plus a 3-yr aged thermal emittance of 0.75
  • 3-yr aged solar reflectance index of 64

Albedo is a measure of solar reflectance noted on a scale of zero to one. A zero albedo denotes 100 percent solar energy absorption. An albedo of one denotes 100 percent solar reflectance.

Excess heat gain drives cooling costs higher. Heat islands in urban areas are a real concern. As a result, you’ll often find solar reflectance indices in newer building codes. Inherently light-colored concrete is well-suited to reduce heat gain. TiO2 concrete delivers some of the highest solar reflectance in the business.

Mitigating Hazard Risk

Extreme weather events drive demands for more resilient construction. The Portland Cement Association (PCA) calls for codes that better promote resilient construction.

MIT’s Concrete Sustainability Hub (CSHub) calls for more stringent codes that account for urban wind conditions. A CSHub Fact Sheet released in May of 2020 says, “The layout, or city texture, of a community can dramatically magnify wind loads. Current building codes, though, don’t consider this contextual effect, leaving many communities at risk.”

Resilient construction can be cost-effective as well. One MIT study looked at a hypothetical $10 million project. Researchers calculated that $340,000 invested in hazard mitigation is recouped in full over the building’s life cycle.

Wind resistance

Concrete is ideally suited to meet mandates for a 20 percent increase in wind pressure and design force. There also updates requiring a five percent increase for critical infrastructure building projects. These were already the subject of more stringent standards in the past.

When reinforced on both horizontal and vertical planes, ICF walls can withstand winds of 180-220 mph. The NRMCA profiles an ICF home in Mississippi that survived Katrina. The residence featured concrete walls, floors and roof.

Flood resistance

Flood resistance is also the subject of updated codes. Designs are to use one of two standards:

  • The 500-year flood elevation
  • Three feet above base flood elevation

Designers cannot rely on protective measures like dams and levees to meet standards.

Fire safety

Fire safety experts often approve of building codes requiring non-combustible materials. Debate continues over the merits of cross-laminated timber (CLT) construction vs. concrete construction. Wood-framed buildings contain more combustible materials. They are often more prone to collapse in fires. The safety of both occupants and firefighters is at stake. There is another benefit that multiplies year after year. The safer the structure, the lower the cost of insurance coverage.

High-performance fire safety includes structural fire resistance requirements for all buildings. Redundant fire safety features apply to residential and assisted living communities. These features recognize the needs of an aging population. Code updates expand mandatory sprinkler requirements as well.

Storm shelters

Residential and commercial storm shelters provide protection in tornadoes, hurricanes and more. Commercial shelters must provide a safe haven for dozens or hundreds of individuals.

Concrete is the go-to material for meeting ICC 500 standards for the design and construction of storm shelters. A FEMA report highlights key provisions. According to a map in the report (Figure 1), storm shelter design wind standards range from 160 mph in eastern PA to 260 mph in the western part of the state.

Additional Updates

There are now more stringent Sound Transmission Class (STC) requirements for residential buildings. These standards are broadly defined to include single-family homes, apartments, hotels and motels. STC ratings attest to how well a structure attenuates sounds ranging from 125 to 4000 Hz. An STC rating is the decibel reduction delivered by a given building material.

IBC 1207 sets a minimum STC 50 in multi-family walls and ceilings. ICFs deliver code-compliant sound attenuation in exterior and interior walls, floors and ceilings. Check out our infographic on ICF sound attenuation. Wood buildings often have STC ratings in the 30s, while ICF structures attain STC ratings in the 50s.

Other IBC code updates address materials transportation, recycling and pollution prevention. There are also updates to site development and site improvement requirements. Some provisions don’t directly involve primary building materials. Enhanced CO2 detection is one example. Many new standards do address sustainability, however. For example, reductions in building water use. Updated air filtration system requirements will improve air quality.

The Portland Cement Association discusses code updates pertinent to the industry here.

Learn More

The Pennsylvania Aggregates and Concrete Association (PACA) serves industry professionals committed to code-compliant designs and design execution. If you need more information, please contact us.