SBCA's Sample TDD Cover Sheet Language to Define CM Scope of Work
The following article provides SBCA's proposed best practice Truss Design Drawing (TDD) Cover Sheet language for CMs to use as a standardize approach with respect to defining their scope of work. The grey highlighted text ties most directly to the commentary provided after the proposed sample language.
Proposed Sample TDD Cover Sheet Language
The Truss Design Drawing(s) (TDD[s]) referenced have been prepared based on the Construction Documents prepared by the Building Designer indicating the nature and character of the design of the Building, including the Building Structural System. The design criteria from the Construction Documents have been transferred to _____________ (Engineering Firm) by [Plant Location]. These TDDs set forth structural component designs and may be part of a Building’s deferred or phased submittals. The Truss Design Engineer’s (also referred to in some Jurisdictions as a “Delegated or Specialty Engineer”), seal on this Cover Sheet and on any TDD represents an acceptance of professional engineering responsibility for the design of the single Truss depicted on the TDD only. The Building Designer is responsible for and shall coordinate and review the TDDs for compatibility with the Construction Documents and the Building Structural System. All capitalized terms not otherwise defined herein are as defined in ANSI/TPI 1, the National Design Standard for Metal Plate Connected Wood Truss Construction (“TPI-1”).
Please review all TDDs and all related notes.
Pages or sheets covered by this seal: XXX thru XXX
My license renewal date for the state of XXX is XXX.
Important Notice:
Truss Design. This TDD utilizes Metal Connector Plate (“MCP”) manufacturer and lumber industry published design values (mechanically or visually graded as indicated), which have been incorporated into the referenced MCP manufacturer’s design software program.
The lumber design values utilized in the truss design correspond to the grade stamp noted on the TDD which grade stamp is to be identified by the Truss Manufacturer prior to cross cutting for manufacturing purposes.
The published lumber design values (a) are calculated and administered by the lumber rules writing agencies using a property range or bending correlation, and are not tension proof tested, (b) are approved by the American Lumber Standards Committee (ALSC) as published design data that are representative of the strength and stiffness of specific grades and species/species groups of lumber, and (c) are further known by ALSC and the lumber rules writing agencies as individual visually or mechanically graded lumber pieces which do not have precise design values.
Neither the Truss Manufacturer nor the Truss Design Engineer can therefore verify or warrant that published lumber design values will exist within the lumber utilized in the Truss when manufactured and delivered.
All Trusses have been designed and are to be manufactured pursuant to TPI-1.
The design assumptions, loading conditions, suitability and use of the Trusses depicted shall be verified by both the Contractor and Building Designer.
The approval of the TDDs and Truss Placement Diagrams (“TPD[s]”) and any field of use of the Trusses, including handling, storage, installation and bracing, is the responsibility of the Building Designer and Contractor. The Truss Design Engineer is NOT the Building Designer or Truss System Engineer (as that term is defined in some Jurisdictions) for any Building.
Upon transmittal of the Truss Submittal Package and upon delivery of the Trusses to the Contractor, Contractor shall verify the design parameters and read all notes and instructions in the TDDs and TPDs and review the practices and guidelines of BCSI and/or its summary sheets as published by the Truss Plat Institute and the Structural Building Component Association (SBCA).
Commentary: ANSI TPI 1 states the following:
Building Structural System: Completed combination of Structural Elements, Trusses, connections and other systems, which serve to transport the Building’s self-weight and the specified loads to the foundation or ground.
Construction Documents: Written, graphic and pictorial documents prepared or assembled for describing the design (including the Framing Structural System), location and physical characteristics of the elements of a Building necessary to obtain a Building Permit and construct a Building. Where required by the statutes of the jurisdiction in which the project is to be constructed, the Construction Documents or parts of the Construction Documents, shall be prepared by a Registered Design Professional.
2.3.5.2 Single Truss Component Design.
The Truss Designer shall be responsible for the design, in accordance with this Standard, of each singular Truss depicted on each Truss Design Drawing.
2.3.1.3 Engagement with the Building Designer.
The Owner shall engage a Building Designer to prepare the Construction Documents and review the Truss Submittal Package.
2.3.1.5 Review and Coordinate Submittal Packages.
The Owner or Owner’s representative shall be responsible for ensuring that the requirement of Section 2.3.4.2 is accomplished.
2.3.2.2 Deferred Submittals.
The Building Designer shall list the Deferred Submittals on the Construction Documents. The Building Designer shall review Deferred Submittals in accordance with Section 2.3.2.3.
2.3.2.3 Review Submittal Packages.
The Building Designer shall review the Truss Submittal Package for compatibility with the Building design. All such submittals shall include a notation indicating that they have been reviewed and whether or not they have been found to be in general conformance with the design of the Building.
2.3.4.2 Information Provided to the Building Designer.
The Contractor, after reviewing and/or approving the Truss Submittal Package, shall forward the Truss Submittal Package to the Building Designer for review.
2.3.4.3 Truss Submittal Package Review.
The Contractor shall not proceed with the Truss installation until the Truss Submittal Package has been reviewed by the Building Designer.
Commentary: ANSI TPI 1 states the following:
3.1.1 Scope.
Chapter 3 of this Standard is the quality standard for the manufacturing processes of metal-plate-connected wood Trusses, and shall be used in conjunction with a manufacturing quality assurance procedure and a Truss design. These provisions shall be included in the In-Plant Quality Assurance Program of each Truss Manufacturer.
3.1.2 Requirements.
Metal-plate-connected wood Trusses shall meet the minimum manufacturing quality requirements specified in Chapter 3 of this Standard, so that design assumptions are met.
3.1.3 Documentation.
Truss Manufacturers and inspection agencies shall establish methods that document the application of these quality assurance procedures throughout the manufacturing process. The Truss Manufacturer’s methods shall be subject to periodic audit for compliance with the requirements of this Standard by an approved inspection agency per Section R109 Inspections of the International Residential Code / Section 109 Inspections of the International Building Code, where required by local authorities having Jurisdiction, or other means.
2.3.6.7 Truss Submittal Packages.
Where required by the Construction Documents or Contract, Legal Requirements or the Building Official, the Truss Manufacturer shall provide the appropriate Truss Submittal Package to one or more of the following: Building Official; Building Designer and/or Contractor for review and/or approval per Section 2.3.4.2
2.3.4.2 Information Provided to the Building Designer.
The Contractor, after reviewing and/or approving the Truss Submittal Package, shall forward the Truss Submittal Package to the Building Designer for review.
2.3.4.3 Truss Submittal Package Review.
The Contractor shall not proceed with the Truss installation until the Truss Submittal Package has been reviewed by the Building Designer.
2.3.4.4 Means and Methods.
The Contractor is responsible for the construction means, methods, techniques, sequences, procedures, programs, and safety in connection with the receipt, storage, handling, installation, restraining, and bracing of the Trusses.