Commentary on Accepted Engineering Practice
Originally published by the following source: SBC Magazine — September 19, 2018. Updated May 19, 2019.
by SBCA Staff with contributions from SBCA/SBCRI Professional Engineers and links to code language from UpCodes
The concept of “accepted engineering practice” is a term often used in the building code where engineering or scientific knowledge is needed to make professional engineering evaluations. The reason this is important is that innovation can only be performed by design professionals willing to provide creative engineered solutions, with the expectation that they will sign and seal their work. Without engineering, buildings would only be built using generic products that have material properties and design methods specified by the building code. Consider all the limitations this would place on high performance and affordable built construction.
Ingenuity is performed via professional engineering (PE), which manages mechanics of materials, fire performance, loads, load paths, resistance to loads, and so forth. A good example of the position that the building code takes, with respect to the work of PEs, is through the approval of signed and sealed accepted engineering practice. This concept is embedded in the fabric of building code language as seen by Graphic 1 and Graphic 2.
Section 1706 Design Strengths of Materials
The design strengths and permissible stresses of any structural material that are identified by a manufacturer's designation as to manufacture and grade by mill tests, or the strength and stress grade is otherwise confirmed to the satisfaction of the building official, shall conform to the specifications and methods of design of accepted engineering practice or the approved rules in the absence of applicable standards.
The design pressure rating of exterior windows and doors in buildings shall be determined in accordance with Section 1709.5.1 or 1709.5.2. For the purposes of this section, the required design pressure shall be determined using the allowable stress design load combinations of Section 1605.3.
Exception: Structural wind load design pressures for window units smaller than the size tested in accordance with Section 1709.5.1 or 1709.5.2 shall be permitted to be higher than the design value of the tested unit provided such higher pressures are determined by accepted engineering analysis. All components of the small unit shall be the same as the tested unit. Where such calculated design pressures are used, they shall be validated by an additional test of the window unit having the highest allowable design pressure.
In addition, the building code, as adopted into law, says that a PE is an approved source (please review graphic 3).
[A] APPROVED SOURCE. An independent person, firm or corporation, approved by the building official, who is competent and experienced in the application of engineering principles to materials, methods or systems analyses.
Supporting data, where necessary to assist in the approval of products, materials or assemblies not specifically provided for in this code, shall consist of valid research reports from approved sources.
Pulling these concepts together, “accepted engineering practice” leads to science based technical evaluation documents or research reports (please review graphic 4) prepared by an approved source, which is a person or company that is “competent and experienced in the application of engineering principles”. In other words, a registered design professional as defined in the code.
Given that generic products and designs are generally the only ones prescribed for use in the code, the concepts surrounding the use of registered design professionals or ANSI 17065 Reports are placed into law to facilitate the use of any ingenious design or method of construction.
From this concept foundation, a research report, prepared by an approved source, shall be acceptable to the building official, which is how approved is defined. Therefore, any proposed material, design or method of construction that complies with the intent of the provisions of this code and is backed up by an ANSI 17065 Report or the signature and seal of a registered design professional meets the intent of being approved.
Where the proposed material, design or method of construction is not approved, the building official shall respond in writing, stating the reasons why the alternative was not approved. This allows the PE to cure any miss interpretations of any provision of the code. This an important function and is the specific scope of work of a building official. (please review graphic 5)
Accepted engineering, via a PE’s expertise, is the code adopted legal pathway to ensure compliance with Federal Trade or Antitrust laws where the goal is to cultivate “free and open markets [which] are the foundation of a vibrant economy. Aggressive competition among sellers in an open marketplace gives consumers — both individuals and businesses — the benefits of lower prices, higher quality products and services, more choices, and greater innovation”.
The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, not less than the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety. Where the alternative material, design or method of construction is not approved, the building official shall respond in writing, stating the reasons why the alternative was not approved.
Supporting data, where necessary to assist in the approval of materials or assemblies not specifically provided for in this code, shall consist of valid research reports from approved sources.
An overarching concept herein is the fact that not everything needed to enforce the code is going to be written in the code. Hence, alternatives will need to be provided and an evaluation made regarding whether or not various products and services meet the intent of the code. The typical policy and procedure for alternative approval is as follows:
- A registered design professional (RDP) or approved source provides an accepted engineering analysis or research report and signs and certifies their belief that the issue being dealt with conforms to the code.
- A research report, also known as a technical evaluation and is provided by an ANSI ISO/IEC 17065 Accredited Product Certification Body and is often generically called an “ICC Report.”
Finally, a question that arises from time to time is whether or not a building official can deny the use of a registered design professional’s work or work found in an ANSI 17065 report. The short answer is “not without a written reason, which defines precisely why the material or design does not comply with the intent of the code.”
For additional information and commentary on the building code, please read the following articles:
- Do Building Officials Have Legal Authority Over a P.E.'s Work?
- How Does an 'ANSI Report' Compare to an 'ICC Report'?
- ICC CEO Sims: ANSI is “Highest Possible Standard” for Approvals
- Commentary on Words/Terms Used in the Building Code
- Commentary on Term Building Official
- Commentary on Term Authority Having Jurisdiction
- Commentary on 'Accepted Engineering Practice'