Working with Updated Code
We are well into 2020 and most of us are becoming comfortable with the current codes we are using. For our engineering design we generally use the International Building Code (IBC) and some portions of the International Residential Code (IRC) as they apply to the residential structures we are working on.
At DEI we have the pleasure of working with several codes now. In Nevada and several other states, we are using the 2018 IBC. In California, we use the 2019 California Building Code and in Oregon the 2019 Structural Specialty Code. Fortunately, the codes adopted in California and Oregon are based on the International Building Code, with some revisions, making it easy to move between them.
As engineers, we use several codes for materials and loading that are listed by reference in the IBC and similar codes. These codes are also updated every three years and typically include revisions with each update. One of our most used codes of this type is ASCE 7. We are currently using ASCE 7-16 and, of course, it has some updates for us to navigate. The good news is there are many publications, seminars and webinars available to cover the revisions in each code. Each code also identifies areas that have been changed and some include commentary covering the change.
With the adoption of the new IBC in northern Nevada, the wind loads were reduced from 130 mph to 120 mph. This is a local revision. Most of the structural revisions to the IBC pertain to creating consistency between codes and clarifications of the existing code along with some other minor revisions.
The energy code changes have impacted our structural designs as the energy loss through the exterior building envelope is more restrictive. We are using high heel trusses to keep the insulation depth consistent to the exterior of the roof system, creating super-insulated walls, and placing rigid insulation below slabs on grade and at the interior and exterior of stem walls. We are spending more time coordinating our framing details and section drawings to meet the building envelope requirements of the mechanical and energy consultants.
New Wildland-Urban Interface requirements seem to pop up without warning as the fire departments get new information. Last year we needed to start protecting the tops and 2 inches down the side of wood deck joists with foil-faced bitumen that prevents the tops of the deck joists from catching fire due to embers falling onto the decks. There are also new flashing requirements for deck ledgers as a part of the fire protection of decks.
The designers and architects we work with have similar challenges with life safety changes that occur with every code change. Based on what I have learned from my colleagues there are new occupancy and fire requirements; some of them simplifying construction. Designers and architects have the biggest challenge as they have to deal with all of the codes and are tasked to understand the codes as they apply to the work of their consultants.
All in all, the new code adoption has not been too difficult to navigate. However, I am sure there are some items that will come up as we continue to use them. We'll let you know!