Design for Code Acceptance (DCA) #1 Flame Spread Performance of Wood Products provides building-code-accepted flame spread ratings for various wood products and species which are normally used as interior finishes for walls, ceilings, and floors in buildings. Wood materials may be used as an interior finish in almost all occupancies. IBC Table 803.9 indicates the finish…
For occupancies such as stores, apartments, offices, and other commercial and industrial uses, building codes commonly require floor/ceiling and wall assemblies to be fire-resistance-rated in accordance with standard fire tests. The 2012 International Building Code permits fire-resistance-rating to be established by several methods. Testing is the primary means (703.2, 2012 IBC), but not the only one. The five…
AWC’s Design for Code Acceptance No. 4 (DCA 4) Component Additive Method (CAM) for Calculating and Demonstrating Assembly Fire Endurance describes a procedure to calculate the fire endurance rating of a wood-frame wall, roof, or floor/ceiling assembly. The procedure is based on combining fire resistance times assigned to each separate component of the assembly without the need for…
One-hour fire-resistance-rated floor/ceiling assemblies that are derived by ASTM E119 testing are typically constructed with 2×10 or 2×12 joists. Joists of lesser depths, such as 2×8, are generally not permitted to be substituted unless the assembly is retested. However, with approval of the building official, the empirical methods in IBC 721.6 and AWC’s DCA 4 can…
Wood and wood-based products are widely used in building construction, due in part to favorable energy performance characteristics. As energy codes become more demanding, use of wood products in the building envelope provides greater advantages due to wood’s natural thermal resistance and low embodied energy combined with excellent structural performance and constructability. Ensuring the building…
Chapter 16 of the National Design Specification (NDS) for Wood Construction provides a code-recognized approach for determining the fire resistance of solid sawn, glulam, and select structural composite lumber (SCL) materials, including laminated veneer lumber (LVL), parallel strand lumber (PSL), laminated strand lumber (LSL), and cross-laminated timber (CLT). Design for Code Acceptance Document 2, titled “Design of…
From the DCA 6 Commentary, “Diagonal bracing can contribute to the stiffness of the deck and, therefore, cause additional lateral loads on the posts. Since center posts receive more vertical load than corner posts, additional lateral load can cause overstress.”
The NDS requires the use of the CM factor for any member subject to moisture contents in excess of 19% for an extended period of time. If there is doubt regarding the moisture content, it is recommended to assume the worst conditions. Since an outdoor deck would be subject to moisture from rain, lawn sprinklers, etc.,…
If the basement ceiling is not finished, it can be installed on the existing floor/ceiling assembly. New proprietary products are available that allow the user to comply with IRC requirements and can be installed from the exterior of the house with lag screws and other fastening systems. This FAQ is based on the presentation…
No, the DCA6 applies only to single level, residential decks that are attached to the house to resist lateral forces. This FAQ is based on the presentation of BCD303 – Design for Code Acceptance No. 6 – Prescriptive Residential Deck Construction Guide. Also, see Page 12 of Part II: Design Values for Structural Members for background on…