SIP DESIGN-BP 9: SIP Electrical

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BEST PRACTICES DESIGN SIP DESIGN BEST PRACTICES SIP DESIGN-BP 9 : SIP Electrical SIP DESIGN-BP 9: SIP ELECTRICAL Page 2 SIP DESIGN-BP 9: SIP Electrical This document is created specifically for design professionals by the manufacturing members of the Structural Insulated Panel Association (SIPA). It dives deeper and provides more background into each of the summarized topics presented in the Design with SIPs: DESIGN CONSIDERATIONS overview which highlights important considerations during the design phase of a Structural Insulated Panel (SIP) structure. Decades of combined knowledge from SIPA manufacturers will help reduce the learning curve and leverage SIPs’ exceptional qualities to achieve the high-performance results owners expect when building with SIPs. The considerations of how and why the best practices were developed as the common industry platform for SIP design are explored here. The index below outlines ten topical areas, listed in sequence to match the order of design considerations and construction. The details in each chapter provide a deeper understanding of the subject matter to facilitate successful SIP design and later implementation. The current chapter is highlighted in blue. 1. High-Performance SIP Building Envelope 2. HVAC Systems with SIPs 3. SIP Structural Capabilities 4. SIP Sizes 5. SIP Shop Drawings 6. SIP Fabrication 7. SIP Installation 8. SIP Roof and Wall Assemblies 9. SIP Electrical 9.1. Vertical and horizontal chases are provided in SIP walls assisting with wiring at outlet and switch heights. 9.2. Wall and roof chases can be added or removed, prior to SIP manufacture. Shop drawings confirm all chase locations to avoid unnecessary cutting of SIPs in the field. Pre-planning for installation and special chase locations is critical. 9.3. Electrical chases should be sealed after electrical rough-in inspection to maximize airtightness. 9.4. An experienced SIP installer is your best insurance that the electrical rough-in will go smoothly. 9.5. Recessed lights are not recommended for installation in SIP roofs. Use of surface mounted LED lighting is recommended. 10. SIP Plumbing SIP DESIGN-BP 9: SIP ELECTRICAL Page 3 SIP DESIGN-BP 9.1: Vertical and horizontal chases are provided in SIP walls assisting with wiring at outlet and switch heights. SIP manufacturers may provide electrical wiring chases in wall panels. The chases are approximately 1-1/4” in diameter and are located in the foam insulation core of the SIP. Horizontal chases in the wall panels are located at switch and outlet heights, approximately 14” and 48” from the bottom of the panel. Vertical chases are located approximately 4’ on center in the wall panels. Additional chases may be added. Consult the manufacturer that you are working with. The sill plates, top plates, cap plates and lumber splines need to be drilled with an approximate 1-1/2” diameter drill bit when the panels are being installed by the installation crew at the vertical or horizontal chase locations. These holes facilitate the installation of the electrical wires during the electrical wiring process. SIP DESIGN-BP 9: SIP Electrical IMAGE 9.2 FLOOR SILL PLATE CHASE CUT OUT TO PASS FROM SIP WALL TO BELOW FLOOR. IMAGE 9.1 SIPS WITH ELECTRICAL WIRING CHASES IMAGE 9.3 INSTALLED LIGHT SWITCHES AND OUTLET BOXES WITH OPEN ACCESS PLUGS NEAR DOOR. SIP DESIGN-BP 9: SIP ELECTRICAL Page 4 IMAGE 9.4 VARIOUS ELECTRICAL BOX INSTALLATIONS IN SIP WALLS IMAGE 9.6 WHEN DESIGNING THE MECHANICAL ROOM, PLAN FOR FRAMING OUT THE WALL TO ACCOMMODATE THE ELECTRICAL BOX AND ALL WIRING. IMAGE 9.5 CEILING BOX INSTALLATION IN SIP ROOF Note: not shown are the four screw fasteners required to support the weight of a ceiling fan. SIP DESIGN-BP 9: SIP ELECTRICAL Page 5 SIP DESIGN-BP 9.2: Wall and roof chases can be added or removed, prior to SIP manufacture. Shop drawings confirm all chase locations to avoid unnecessary cutting of SIPs in the field. Pre-planning for installation and special chase locations is critical. Electrical chases are cut prior to adhering facers (typically OSB) to the SIP’s core. Therefore, it is important that proper chase locations be confirmed prior to project entering production. Aside from “standard” chases, referenced in 9.1, above, it is possible to add additional chases. Consideration must be given to the number and location of chases. It is important to remember that a SIP functions as a composite, with each material acting together to create a structural component far greater than any of the materials tested independently. Should electrical chases need to be added at a later date, consult the manufacturer for guidance. Architectural electrical plans are intended to be interpreted by electricians who are familiar with electrical code requirements, circuit runs, etc. SIP manufacturers look to electrical contractors to provide the specific chase locations that coincide with their installation plan. In many cases, two separate electricians may come up with completely different wire run approaches for the exact same architectural electrical plan. Typically, 2 See SIP Design-BP 5: SIP Shop Drawings IMAGE 9.7 the default factory electrical chases are sufficient to provide adequate access for electrical runs; however, it would be best to review the SIP shop drawings1 with your electrician and let your SIP manufacturer know if you would like to add any additional electrical chases within the SIPs. SIP DESIGN-BP 9: SIP ELECTRICAL Page 6 SIP DESIGN-BP 9.3: Electrical chases should be sealed after electrical rough-in inspection to maximize airtightness. All penetrations made in the SIP facers need to be foamed to minimize air flow through the chases. This is important to do after the electrical rough-in and inspection is complete around all electrical box locations. The process can be done simply by using a minimal expanding foam similar to what is used around windows and doors. Placing a small amount behind