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Understanding ASCE 7-16

What is ASCE and why is it important to the solar industry?

Building codes are the official statement on building safety. Codes and standards are designed to provide the common language and requirements for the design, construction, and operations and of a building. The codes are the set minimum standards that address all aspects of construction such as; fire, life safety, structural, plumbing, electrical, and mechanical. Building codes are necessary to reduce property damage and loss of life.

Who makes the codes?

The International Code Council (ICC), uses governmental consensus process to develop construction and public safety codes. A new code cycle begins every three years to ensure that the public is provided with the highest level of safety. As soon as the new edition of the code is published and adopted, the next code cycle begins. The International Building Code (IBC) is the code developed by the ICC. It is the code standard adopted by MOST jurisdictions in the US. ASCE 7-16 follows the IBC 2018 requirements. California follows the CBC 2019 code which is the same as the IBC 2018 with the addition of California specific requirements.

wind map

What exactly is the ASCE and why is it changing?

The American Society of Civil Engineers (ASCE) is always working to ensure that all infrastructure is safe, resilient, and sustainable. The ASCE is a tax-exempt professional body which was founded in 1852. ASCE provides technical and professional engineering content and creates the codes and standards used to protect the public. This group of civil engineers are responsible for developing innovative practices and technologies to keep the codes and standards updated to meet the ever-changing demands of society. Although these code changes can often lead to confusion and frustration when trying to interpret them, the changes are necessary for building safety. 

 

The most recent code that is being adopted in 2020 is ASCE 7-16. This is the first code to have a dedicated section for the installation of solar systems on buildings. The previous code, ASCE 7-10, did not specifically discuss solar installations. Engineers and designers were required to reference the components and cladding section to determine the appropriate solar design. One of the major additions to the code is including more defined wind zones. Previously, there were no solar specific wind calculations and the design was based on roof surface alone and did not take into account that a solar array would be placed on top. Although this is usually acceptable, there have been some catastrophic failures and damage in locations with high wind loads. The new ASCE 7-16 code hopes to eliminate and avoid these failures and correct these costly issues.

 

Since ASCE 7-16 follows solar specific wind tunnel testing, there may be decreased wind pressures between upper and lower surfaces of a solar array (depending on array geometry). Additionally, sections of the code allow for reductions in wind loading due to specific geometric factors of the array. Everest has taken these variables into consideration with racking design.  Another issue that was revealed during the wind tunnel testing, evaluated by the code-writing team, is that there is an increased net wind pressure caused by roof edge effect and large gaps. Many new provisions were considered because of these discoveries. The locations that will be most affected by these changes are places in Hurricane zones or high wind zones such as Texas, Florida, The Gulf of Mexico, Puerto Rico and the Carolinas.

Who enforces these codes?

The Authority Having Jurisdiction (AHJ) is defined as “an organization, office, or individual responsible for enforcing the requirements of a code or standard, or for approving equipment, materials an installation, or a procedure.” For every project, it is necessary to consult the local AHJ to ensure that the local codes are being followed and enforced. The local AHJ ensures that the project is code compliant and safe. For every solar project, it is necessary to consult the local AHJ to ensure code compliance. The AHJ is able to interpret the codes and determine whether there are special requirements that need to be in place for a specific geographic location. 

edge mods

Roof Type/Roof Zones/Effect of Code Change:

Monoslope, Gable, and Flat Roofs

The new ASCE 7-16 code now discerns between roof type. Previous codes did not distinguish between roof type for determining wind pressure. Gable and hip roofs now have different requirements and increased roof zones. For gable roofs, zone 1 remained unchanged. Zone 2 has been divided into 3 sections; 2E, 2R and 2N. Zone 3 has been divided into 2 zones; 3E and 3R. Hip roofs have stayed the same in zones 1 and 3, but zone 2 has been divided into 2E and 2R. These new zones take into account the wind pressure coefficients when roof pitch increases or decreases. 

Where are our certification letters located?

Everest has obtained ASCE 7-16 certification letters for our CrossRail and CrossRail Shared Rail systems. The letters can be found on the specific product pages under the "Downloads" tab, as well as on the "Technical Information" page under the specific product list. 

roof zones

Design Impacts

Luckily, there is minimal design impact for most Everest installations. There is no change in the code for snow load, exposure category or risk category. The largest changes apply to wind and roof zones. 

What is Everest doing to adhere to code changes?

Everest is dedicated to ensuring its customers have all of the required documentation for their solar projects. This includes state-stamped engineering letters and online tools to assist with any PV design needs.

 

Additionally, Everest’s commitment towards creating robust products means the customer will have few setbacks in choosing Everest attachment and rail products. Many of the products that were designed for ASCE 7-10 loads also work just as well using ASCE 7-16 loads. Everest will continue to innovate and create products with superior strength at a cost-competitive value, considering all current and future changes to the code.

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