Code or standard?
What's the difference between a code and a standard?
Almost every consulting engineer works with codes and standards on a daily basis, but do you know the difference between a code and a standard?
According to the National Institute of Standards and Technology (NIST) Circular No. A-119, Revised, a standard is "[t]he definition of terms; classification of components; delineation of procedures; specification of dimensions, materials, performance, designs, or operations; measurement of quality and quantity in describing materials, processes, products, systems, services, or practices; test methods and sampling procedures; or descriptions of fit and measurements of size or strength." In plain English, a standard consists of technical definitions, procedures, and/or guidelines that specify minimum requirements or instructions for manufacturers, installers, and users of equipment. This can be done by specifying either the methods or the results; the latter is known as "performance specifying." Most importantly, a standard provides standardization or agreement within the industry, which translates to a common reference among engineers, manufacturers, and bidders.
In the United States, there are several types of standards, but engineers are most familiar with "voluntary consensus standards" such as ASHRAE Standard 90.1, ASTM D975, IEEE SI-10, NECA 1, and NFPA 70. These standards are developed in a manner that is, according to NIST A-119, "open, (considers) balance of interest, (has) due process, an appeals process, (and relies on) consensus, which is defined as general agreement, but not necessarily unanimity." There are also requirements that the standard be maintained on a consistent schedule by the organization that sponsors the standard.
A code is a standard that has been enacted into law by a local, regional, or national authority having jurisdiction so that the engineer or contractor is legally obligated to comply with the code. Noncompliance can result in being prosecuted. The code may be an industry, government, or voluntary consensus-based standard. A code can include references to standards, which means the standards are incorporated by reference and therefore are part of the code and legally enforceable.
It's important to note the difference between a code and a model code such as the International Building Code (IBC). A model code is developed by a standards organization, typically using the voluntary consensus standard process and subject matter experts. The intent of a model code is to have an industry-wide standard that can be adopted and customized by local jurisdictions, thereby saving the jurisdiction the time and expense of developing and maintaining their own code. This also allows for a certain level of standardization across jurisdictions, permitting contractors to have a understanding of the Owner's expectations and potentially lowering the cost of manufactured goods due to similar requirements across jurisdictions. A model code is not enforceable until it is adopted by a jurisdiction, and typically a jurisdiction will require significant review and some modification of the code to ensure that the code is acceptable to the jurisdiction. This is often why a jurisdiction's adopted code may be several cycles behind the latest model code.
To recap, "voluntary consensus standards" are commonly used in the United States to specify what subject matter experts consider to be the minimum requirements and instructions for manufacturers and users of equipment. Codes are standards that are adopted by jurisdictions and are legally enforceable; however, model codes are not legally enforceable.
Michael Heinsdorf, PE, LEED AP, CDT is an engineering specification writer at ARCOM MasterSpec. He has more than 10 years of experience in consulting engineering, and is the lead author of MasterSpec Electrical, Communications, and Electronic Safety and Security guide specifications. He holds a BSEE from Drexel University and is currently pursuing a master's in engineering at Drexel University.