The design and construction of buildings has drastically changed in the last decade. A driving force behind this transformation is the changing world of codes and standards.
The model building code that regulates the work of AWCI contractors is the International Building Code, or IBC. The code is administered by the International Code Council, or ICC. This code is on a three-year cycle for modification based on continuing research and development in the built environment. New building codes and technology advances are having great influence over today’s construction industry.
Changes Within the Model Codes
A significant change brought about by new code language deals with the height to which buildings, based on structure type and occupancy, can be built. Most notably are combustible and conventional wood buildings that are now allowed to achieve building heights once considered unfeasible. This can increase the scope of work for the contractor. A reduction in the requirements for fire-resistive walls is partially offset by acoustical performance mandated in both residential and commercial applications. Direction is now provided by the model codes on the encapsulation of structural columns embedded in fire-resistive construction.
There are newer regulations on “hardening” the elevator hoist ways and stairwells in high-rise buildings that rise more than 420 feet above grade. Water-resistive barriers and air barriers are now required on the exterior envelope. A drainage plane is needed in some exterior walls. A recent initiative focuses on the fire-resistance of exterior cladding. This is in response to numerous high-rise fires of late. There is code language now in place that will affect certain types of metal panel construction. This may impact contractors who work in exterior wall construction.
The Extensive Use of Special Inspections
The need for “special inspections” is extending into more areas of construction. The concept of special inspections dates back to the late 1980s, which in turn led to Chapter 17 of the International Building Code. These inspections are expanding within the model code and currently adopted by individual states. Inspections must be performed by licensed design professionals. Depending on the item, the inspections can either be periodic or continuous. Items include cold-formed steel prefabrication, cold-formed steel trusses with spans greater than or equal to 60 feet, and EIFS unless the design calls for a water-resistive barrier that includes a drainage plane. Also, through-penetration firestops require special inspections for high-rise construction.
The Rise of Mass Timber
The wood industry has seen an increase in the allowable building heights that can be obtained using conventional lumber. Work is being done to gain acceptance of cross laminated timber. This type of construction is termed “mass timber” because its fire behavior is deemed similar to heavy timber. From a contractor’s standpoint, it may not diminish the potential for the use of gypsum board, but it could significantly erode market share for the use of cold-formed steel framing.
Building Codes Move into Sustainability
Sustainability has become a significant design consideration, and it is now regulated by both codes and standards. The U.S. Green Building Council first drafted LEED®, Leadership in Energy and Environmental Design, in the late 1990s. While compliance is still voluntary, it has achieved its goal of changing the way buildings are designed and built. The standard has also evolved into a highly sophisticated regulation with the release of LEED v4.1. This places more responsibility on the contractor for selecting and sourcing the correct materials. The requirement for Environmental Product Declarations and Health Product Declarations, which document the sustainable attributes of selected building materials, falls on the contractor to submit prior to bid. Diverting construction waste from landfills also must be accomplished by the contractor.
Through the International Energy Conservation Code, designers must meet specific operational energy goals by the building systems employed (HVAC) and the thermal efficiency of the building exterior envelope. The required use of continuous insulation impacts the designer as well as the contractor. Fasteners must be analyzed for structural capacity and thermal resistance. The responsibility for overall performance falls on the contractor, who is striving to provide alternates. Commissioning of the exterior wall is now a requirement. Commissioning mandates air leakage testing on the completed building.
Recently there has been a merger of USGBC, ICC and the American Society of Heating, Refrigerating and Air-Conditioning Engineers to meld their separate sustainability codes and standards into one cohesive document. That document is written around both the ASHRAE Standard 189.1, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings, and the ICC’s International Green Construction Code.
The Increasing Rate of Change in Standards
Not only are codes changing, but so are the standards that the code references. ASTM standards are widely referenced in the building codes. Their rigorous protocol, a time-consuming process, assures consistency of high-quality reference documents. This process has been accelerated as evidenced by the changes occurring in cement plaster and lath. Three standards now cover this material and trade, a couple of years ago there were only two. In 2018, ASTM C926, Standard Specification for Application of Portland Cement-Based Plaster, had three approved versions. They were denoted as 18, 18a and 18b. The current specification is 20, understanding that there was a 2019 version. This indicates five editions in two years. All had changes that potentially impact the contractor. The ASTM for lath is ASTM C1063, Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster, which has also gone through numerous changes in the same time period.
Building codes and architectural specifications cite standards in order to assure quality and code compliance. Exactly which version of a standard is referenced both in the code and in the architectural specifications becomes of key importance. The same version of a standard should be cited in the building code and the project’s architectural specifications.
This will assure code compliance. The contractor must be cognizant of which version of the standard was specified by the architect, which version of the standard was referenced in the building code, and which version of the standard was used during installation.
Standard Reference for Cold-Formed Steel
Change is also occurring in the cold-formed steel industry. Historically, cold-formed steel framing as a code-accepted material was defined by ASTM. For nonstructural framing the standard was ASTM C645, Standard Specification for Nonstructural Steel Framing Members. The same was true for how the material was to be installed. This standard was ASTM C754, Standard Specification for Installation Steel Framing Members to Receive Screw-Attached Gypsum Board Products.
Currently, the steel industry is transitioning away from ASTM to standards from the American Iron and Steel Institute. For the first time, the latest version (2018) of the IBC makes no reference to ASTM for nonstructural framing. The new referenced standard is AISI S220, North American Standard for Cold-Formed Steel Framing – Nonstructural Members. This transition has implications for the design community as well as the contractor. In architectural specifications the reference had been to ASTM, which directly links to the building codes. With ASTM no longer referenced in the code, it opens the way for non-code compliance issues at the job site.
The Focus on Prefabrication
Another example of change is a proposed standard by the ICC to regulate modular construction and prefabrication. The standard is called ICC 1200, Standard for Off-Site Construction: Planning, Design and Fabrication. The goal is to have this new standard drafted and complete by 2021. While this standard is still in its initial stages, it may have significant impact on contractors performing off-site prefabrication of any type. There is very strong potential for more oversight through third-party inspections.
OSHA Making Safety Standards More Stringent
Changes in safety standards for the workforce are driven mainly by tighter restrictions imposed by the Department of Labor’s Occupational Safety and Health Administration. The recent modification to an existing standard drastically reduced the allowable exposure to respirable crystalline silica at the construction job site. The new exposure limit is 50 µg/m3 of respirable crystalline silica in an 8-hour time weighted average. The newly revised standard includes monitoring the air in the workplace, medical surveillance of individuals who exceed a threshold exposure level, the establishment of a competent person, extensive documentation and extensive training throughout the contracting firm.
The new ruling has options for both a prescriptive and a performance-based approach. If contractors use established tasks and follow prescriptive engineering controls, they are deemed in compliance. The performance option includes monitoring the air adjacent to the work area. In either case, the contractor must provide a written exposure plan specific to the tasks, and document the controls that will be utilized. This standard has changed the way common tasks on the job site are performed even down to simple housekeeping procedures.
OSHA announced changes to its Beryllium Standard for Construction and Shipyards in October 2019. Similar to silica, the standard has reduced the permissible exposure limit for beryllium; the new limit is 0.2 µg/m3. The main impact of this standard is for those individuals involved in abrasive blasting that utilizes slags that contain trace amounts of beryllium.
OSHA Concerned with Heat-Related Illness
OSHA is also looking at heat-related illnesses and started a campaign to raise awareness. This concern could become a new standard, but it may not happen in the near future. This is due to Executive Order 13771, which was signed in January 2017 and requires that a federal agency repeal two existing regulations for every proposed new regulation.
A decade of transformation based on changing codes and standards has brought about the net result of buildings that are healthier and more energy efficient. They ensure a safer environment for the workforce that is coupled with increased potential for the innovative contractor. However, this does not come without cost. The tangible cost is an increase in expenditures to physically meet these tighter codes and standards. The intangible cost lies in not knowing these changes, along with the added risk when proposing alternates. Access to information then becomes critical. For the contractor, this requires knowledge of which standards are referenced, which edition of those same references will be enforced, and how to position the firm for greater opportunities.
Robert Grupe is AWCI’s director of technical services. Send your questions to [email protected], or call him directly at (703) 538.1611.
