The concept of delegated design has been around for many years. Recent conversations in professional circles center on its increased usage. However, there is a certain confusion that is often related to the process. A basic definition of delegated design is when the design professional or architect of record establishes the performance requirements for an element of a building, and a contractor assumes the responsibility of designing that element.
In this context, an example would be the design of structural cold-formed steel framing. Delegated design now includes building envelope assemblies, and it is trending toward both interior non-structural assemblies and suspended acoustical ceilings. What is driving this trend is the increased level of complexity of these systems and increased oversight through the ever-expanding role of evolving model building codes and regulatory standards.
Delegated design is seen as a design collaboration and should not be confused with design-build or design-assist. Design-build is a project delivery method where the owner signs one contract with a single organization that will both design and construct a given building or structure. In design assist the contractor provides technical information to the architect of record in crafting the project design. In this scenario there are individual contracts between the owner and the architect, and then again between the owner and the contractor. The architect is liable for the overall design whereas the contractor is liable only for the information that is provided. The contractor in all cases could be the general contractor, or the specialty contractor with specific expertise.
The design collaboration in delegated design is where the architect of record provides the performance requirement for a specific element of a building. This could be the fire, sound, structural, moisture and sustainability performance requirements of the element, and the contractor is allowed to design the individual element that meets these requirements. An example of this would be a partition that needs to be so tall that the framing non-structural must be a one-hour fire partition and meet a 50 STC sound rating. This implies that the final system must also accommodate a certain level of building movement, be structurally stiff enough to support brittle finishes, and the components have specific sustainability attributes. The use of this design process is not common for interior partitions, but many architects are re-thinking how they approach design solutions.
The contractor then provides a design solution for the assembly that is formally proposed through the submittals process and may include shop drawings that are stamped by a professional engineer. For cold-formed steel framing the engineer may be an employee of the manufacturer of the framing products or an independent specialty structural engineer. One area where this process is used extensively is when the prefabrication of building components is utilized.
Accurately defining the scope of the delegated design is extremely critical and must be clearly integrated into the construction documents. These documents, the architectural specifications and the drawings should be tightly coordinated so there is no confusion as to the intent of, and therefore adherence to specified performance requirements. In the architectural specification the definition starts in Division 1. Here it covers the required submittal procedures, shop drawings, product data and if samples are required. Section 01 335 73, Division 1, focuses on the Delegated Design Procedure (Masterformat® 2020). More information should then be conveyed in the appropriate specification section. Examples here include the following:
-
054000 Cold-Formed Metal Framing -
092116 Gypsum Board Assemblies -
092216 Non-Structural Metal Framing -
095700 Acoustical Ceilings
To some extent the architect in delegated design controls the process, but not in designing the individual elements. Specifications call for submittals to be either action or informational. The action submittals are those that require action or formal approval from the architect. This includes approving stamped submittal drawings, calculations that come from the delegated designer. Informational submittals are used to convey important information.
Benefits to contractors in this concept include elevating contractors to where they have more influence in the design process. Further, it provides greater control over the incurred risk. Communication plays an acute role in the design and construction process. Understanding the interfaces between adjacent building components takes on heightened importance. Also, delegated design can work extremely well where a contractor has total control of the delegated design element. Relating to cold-formed steel framing and to get a better understanding of the responsibilities of the involved parties: CASE National Practice for Specialty Engineers and the AISI Code of Standard Practice S202.
Understanding the full scope of the work is essential. Questions on connections to structure should be clearly articulated prior to bid. This would include structural embeds, and who is responsible for the design. There is a trend for this practice to seep down into work that followed the more traditional process for design—bid-build delivery systems. It may provide additional opportunities for the contractor who is cognizant of its ramifications.
Robert Grupe is AWCI’s director of technical services. Send your questions to grupe@awci.org, or call him at (703) 538.1611.
Want more news and information like this? Subscribe to AWCI's Construction Dimensions for free now.
