ANSI/APA PRS Standard for Performance-Rated Structural Insulated Panels in Wall Applications

Transcription

1 ANSI/APA PRS Standard for Performance-Rated Structural Insulated Panels in Wall Applications 2008 APA - The Engineered Wood Association Draft 2 January 2008 Copyright 2008 by APA 7011 South 19th Street, Tacoma, WA Telephone: (253) Fax Number: (253)

2 (Draft 2) ANSI/APA PRS Standard for Performance-Rated Structural Insulated Panels in Wall Applications 1. Scope 1.1 The PRS performance-rated structural insulated panels (SIPs) are structural sandwich panels consisting of a foam plastic insulation core securely bonded between two structural facings made of wood structural panels. 1.2 The PRS performance-rated SIPs are intended for use as a structural element in above-grade wall applications. This standard covers SIPs intended for wall applications in low seismic design categories (SDC C or lower) or low wind zones (130 mph or less), as defined in ASCE 7. The applicability of this standard may be subject to the limitations shown in Annex A1. Note 1: PRS and 610.3, which are being developed, will cover roof and floor applications, respectively. 1.3 Unless otherwise qualified, the facings used for the PRS performancerated SIPs shall have the strength axis oriented in the vertical direction, and the PRS SIPs shall contain no core joints. Holes and opening, and notching and drilling of SIPs, other than the precut hole for electric box, are beyond the scope of this standard. 1.4 Products carrying the PRS performance-rated SIP label are to be installed in accordance with the pertinent building code requirements and the recommendations published by APA and the manufacturer. 1.5 The PRS Performance-rated SIPs are intended for use in dry-service conditions where the average moisture content of wood structural panels is less than 16% and the panels are protected from the weather. 1.6 This standard provides characteristic properties for the performance-rated SIPs. To qualify for marking as a PRS performance-rated SIP, the SIP product shall demonstrate conformance to the qualification and quality assurance requirements set forth in this standard. 2. Referenced Documents 2.1 ASTM Standards: C a Test Methods for Breaking Load and Flexural Properties of Block-Type Thermal Insulation C (2007) Test Method for Water Absorption of Core Materials for Structural Sandwich Constructions C a Test Method for Shear Properties of Sandwich Core Materials C Specification for Rigid, Cellular Polystyrene Thermal Insulation D a Test Method for Compressive Properties of Rigid Cellular Plastics D Test Method for Apparent Density of Rigid Cellular Plastics January 2008 Copyright 2008 by APA Page 2 of 16

3 D Test Method for Tensile and Tensile Adhesion Properties of Rigid Cellular Plastics D Specification for Adhesives for Structural Laminated Wood Products for Use under Exterior (Wet-Use) Exposure Conditions D Practice for Evaluating Allowable Properties for Grades of Structural Lumber D Test Methods for Mechanical Properties of Lumber and Wood-Base Structural Material (D xxxx SIP adhesive standard under development by D14) E 72-05Test Methods of Conducting Strength Tests of Panels for Building Construction E 84-07a Test Method for Surface Burning Characteristics of Building Materials E Test Methods for Water Vapor Transmission of Materials E Test Methods for Determining Structural Capacities of Insulated Panels E Test Methods for Cyclic (Reversed) Load Test for Shear Resistance of Walls for Buildings F Specification for Driven Fasteners: Nails, Spikes, and Staples 2.2 Other Standards and Referenced Documents: ASCE 7-05 Minimum Design Loads for Buildings and Other Structures PS 1-07 Structural Plywood PS 2-04 Performance Standard for Wood-Based Structural-Use Panels PS American Softwood Lumber Standard CSA O121-M1978 (R2003) Canadian Douglas Fir Plywood CSA O Canadian Softwood Plywood CSA O Construction Sheathing CSA O (R2006) Standards for OSB and Waferboard ICC-ES AC04 (June 2007) Acceptance Criteria for Sandwich Panels ICC-ES AC05 (June 2005) Acceptance Criteria for Sandwich Panel Adhesives ICC-ES AC10 (February 2007) Acceptance Criteria for Quality Documentation ICC-ES AC85 (July 2003) Acceptance Criteria for Test Reports UL 723 (2003) Test for Surface Burning Characteristics of Building Materials 3. Terminology 3.1 Definitions -- See the referenced documents for definitions of terms used in this standard. 3.2 Description of terms specific to this standard: Characteristic Value The structural property estimate, typically a population mean for stiffness properties or a tolerance limit (5 th percentile with 75% confidence) for strength properties, as estimated from the test data that is representative of the population being sampled. Core The light-weight middle section of the SIP composed of foam plastic insulation, which provides the link between the two structural panel facings. January 2008 Copyright 2008 by APA Page 3 of 16

4 Facing The wood structural panel material that forms both exterior layers of the SIP. For the purpose of this standard, the facing materials on both exterior layers of the SIP shall be of the same type and thickness. Flame Spread Index A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84. Lintel A structural element used to support gravity loads above opening of SIP wall panels, also known as a door or window header. Oriented Strand Board (OSB) A performance-rated structural panel meeting DOC PS 2, CSA O325, or CSA O437, and manufactured to meet requirements specified in this standard. Plywood A conventional all-veneer panel meeting DOC PS 1, CSA O121, or CSA O151, and manufactured to meet requirements specified in this standard. Qualified Inspection and Testing Agency An agency that meeting the following requirements: (a) Has access to the facilities and trained technical personnel to verify that the grading, measuring, species, construction, bonding, workmanship, and other characteristics of the products as determined by inspection, sampling, and testing comply with all applicable requirements specified in this standard, (b) Has procedures to be followed by its personnel in performance of the inspection and/or testing, (c) Has no financial interest in, or is not financially dependent upon, any single company manufacturing the product being inspected or tested, and (d) Is not owned, operated, or controlled by any such company. R-Value, Thermal Resistance The inverse of the time rate of heat flow through a building thermal envelope element from one of its bounding surfaces to the other for a unit temperature difference between the two surfaces, under steady state conditions, per unit area (h ft 2 F/Btu). Smoke Development Index A comparative measure, expressed as a dimensionless number, derived from measurements of smoke obscuration versus time for a material tested in accordance with ASTM E 84. Spline A strip that fits into a groove cut into the longitudinal edges of the two structural insulated panels to be joined ( Surface Spline, see Figure 1). Alternately, the strip (spline) can be a section of structural insulated panel ( Insulated Panel Spline, see Figure 2) with overall thickness equal to the core thickness of the two structural insulated panels to be connected. The length of the spline, if Figure 1. Surface Spline January 2008 Copyright 2008 by APA Page 4 of 16

5 not full height, shall be continuous with each segment of no less than 4 feet. Structural Insulated Panel (SIP) A structural sandwich panel which consists of foam plastic insulation core securely bonded between two structural facings made of wood structural panels. Wood Structural Panels A panel product Figure 3. Insulated Panel Spline composed primarily of wood which, in its commodity end use, is essentially dependent upon certain mechanical and/or physical properties for successful end-use performance. Such a product carrying the trademark of a qualified inspection and testing agency shall conform to performance requirements of one or more of the enduses specified in DOC PS1 or PS2, and the requirements specified in this standard. Such a panel shall be identified in a manner clearly conveying its intended end use. Examples of wood structural panels are oriented strand board (OSB) and plywood. 4. Performance Criteria and Requirements This section provides performance criteria and requirements for performance-rated SIPs, which shall be qualified in accordance with this standard by demonstrating conformance to the performance requirements specified herein. 4.1 Wall Systems SIPs for above grade wall construction shall comply with Figures 3 and 4, and shall have nominal panel thickness as specified in Section 4.2. The strength axis of the facings shall be in the vertical direction. 4.2 Physical Dimensions Walls for residential structures constructed with SIP systems in accordance with this standard shall comply with the shapes and nominal cross-sectional dimensions required in this section. Figure 2. Example of SIP Wall January 2008 Copyright 2008 by APA Page 5 of 16

6 4.2.1 SIP Panel Thicknesses The PRS performance-rated SIPs shall have a nominal panel thickness of 4-1/2 or 6-1/2 inches subjected to the tolerances specified in Section SIP Panel Tolerances -- The tolerances for the PRS performance-rated SIPs permitted at the time of manufacture shall be as follows: Panel Thickness Plus or minus 1/8 inch Panel Width Plus or minus 1/8 inch Panel Length Plus or minus 1/4 inch Figure 4. Cross Section of SIP 4.3 Component Requirements Core The PRS performance-rated SIPs shall be produced using a foam plastic insulation core material meeting one of the following requirements: a) ASTM C 578 Type I, or b) Polyurethane foam meeting the physical properties shown in Table 1. Table 1. Minimum Properties for Polyurethane Insulation Used as the Core of SIPs Physical Property Polyurethane Density, core nominal, (ASTM D 1622) 2.0 lb/ft 3 Compressive resistance at yield or 10% deformation, whichever occurs first, (ASTM D 1621) 19 psi (perp to rise) Flexural strength, min, ( ASTM C 203) 30 psi Tensile strength, min. (ASTM D 1623) 35 psi Shear strength, min, (ASTM C 273) 25 psi Substrate adhesion, min, (ASTM D 1623) 22 psi Water vapor permeance of 1.00-in. thickness, max, (ASTM E96) 2.3 perm Water absorption by total immersion, max, (ASTM C 272) 4.3 % (volume) Dimensional stability (change in dimensions), max, (ASTM D2126 (7 days at 158 F/100 % humidity and 7 days at -20 F) 2 % Core materials used in manufacturing the PRS performance-rated SIPs shall have a nominal thickness of 3-1/2 or 5-1/2 inches with a flame spread index of not more than 75 and a smoke developed index of not more than 450 when tested in the maximum thickness intended for use in accordance with ASTM E 84 and UL Expanded polystyrene (EPS) or extruded polystyrene (XPS) core insulation materials qualified under this standard and used in manufacturing the PRS performance-rated SIPs shall bear a label containing, as a minimum, manufacturer identification, product standard and type, flame spread index, smoke development index, January 2008 Copyright 2008 by APA Page 6 of 16

7 and name, logo or identification of a qualified inspection agency. Polyurethane core shall be certified by a certificate of conformance Facing The PRS performance-rated SIPs shall be produced using wood structural panels meeting the requirements of PS 1, PS 2, CSA O121, CSA O151, CSA O325, or CSA O437, and shall be qualified for conformance to the minimum properties specified in Table 2. Table 2. Minimum properties for PRS SIP facing materials (a) Flatwise Bending Flatwise Bending Stiffness (b) (lbf-in. 2 /ft) Strength (c) Tension (c) (lbf/ft) (lbf-in./ft) Density (b,d) (pcf) Along Across Along Across Along Across 54,700 27, ,800 6, (a) Tested in accordance with Annex A2 of this standard. (b) Mean test value. (c) Characteristic test value (5 th percentile with 75% confidence). (d) Based on oven-dry weight and oven-dry volume Facing materials qualified under this standard and used in manufacturing the PRS performance-rated SIPs shall be identified by a grade mark or certificate of inspection issued by a qualified inspection agency in accordance with PS 1, PS 2, CSA O121, CSA O151, CSA O325, or CSA O437. The grade mark or certificate of inspection shall also include a label signifying the conformance with this standard Adhesives Laminated adhesives are required to bond the core to facings of a SIP during manufacture. The PRS performance-rated SIPs shall be produced using adhesives specifically intended for the lamination of SIPs conforming to the requirements of Type II Class 2 in ICC-ES AC05 or ASTM D xxxx, and the qualification requirements specified in this standard Each container of adhesive qualified under this standard and used in manufacturing the PRS performance-rated SIPs shall bear a label with the adhesive manufacturer identification (such as name or logo), adhesive name and type, and the name (or logo) of the certification agency Lumber The top and bottom plates of the PRS performance-rated SIPs shall be manufactured using lumber conforming to the requirements of PS 20 and bearing the trademark and grade of a lumber grading agency recognized by American Lumber Standards Committee (ALSC) or Canadian Lumber Standards Accreditation Board (CLSAB), provided that the wood species/grade meets or exceeds the mechanical properties and specific gravity of No. 2 SPF. Less than full-size pieces of lumber used to frame around openings in SIPs shall be cut from lumber bearing the trademark and grade listed above Fasteners Nails used for connection of the PRS performance-rated SIPs to wood members shall be common or galvanized box nails meeting the requirements of ASTM F SIP screws used for the connection of the PRS performance-rated SIPs to wood members shall be fabricated from steel and sized to penetrate the wood member to which the assembly is being attached by a minimum of 1 inch. The screws January 2008 Copyright 2008 by APA Page 7 of 16

8 shall be corrosion resistant and have a minimum shank diameter of inch and a minimum head diameter of inch Other components Other components used as part of the SIP assembly qualification to demonstrate conformance to the SIP properties specified in this standard shall have a specification and shall be documented. 4.4 SIP Requirements The PRS performance-rated SIPs shall meet or exceed the properties shown in Table 3 when qualified in accordance with Section Table 3. Properties for PRS Performance-Rated SIPs in Wall Applications Properties Minimum Test Value (a) SIP Maximum Load at Deformation Limit Dimension Load Def. Limit Test Load Racking Resistance (lbf/ft) -- (b,c) 945 1/8 315 Axial Load Capacity (lbf/ft) 8 height (c) 9,600 1/8 3, height (c) 9,300 1/8 3, /2 x Transverse Load Capacity 4-1/2 x (lbf/ft 2 H/240 (d) 27 ) 6-1/2 x /2 x span 3,180 1,060 Lintel Load Capacity (lbf/ft) 4 span 1,620 L/360 (e) span span (a) The tabulated values are average test values and not intended for design use. The average test value shall meet the minimum requirements for both maximum load and the load at the specified deformation limit. (b) Based on 8d common (0.131 x 2-1/2 ) nails at 6 oc. (c) For both 4-1/2 and 6-1/2 thick SIPs. (d) H is the wall height in inches. (e) For lintel depths of 12 inches. L is the lintel span in inches SIPs qualified under this standard shall be identified and labeled in accordance with the requirements specified in Section Qualification Requirements 5.1 Component Qualification Requirements Core Materials -- The properties of core materials shall be qualified to satisfy the requirements specified in Section Facing Materials Facing materials shall be qualified to satisfy the requirements specified in Section and Annex A Adhesives Adhesives used for SIPs shall be qualified to satisfy the requirements specified in Section January 2008 Copyright 2008 by APA Page 8 of 16

9 5.2 SIPs Qualification Requirements The PRS performance-rated SIPs shall be qualified based on the requirements specified Section 4.4. Qualification tests for SIPs shall be conducted in accordance with the principles set forth in Section Qualification Test Methods for SIPs 6.1 General Sampling procedures, number of samples, test methods, and data analyses for the PRS performance-rated SIP product qualification shall conform to the principles set forth in the referenced standard of each qualification test method unless specifically noted in this section Specimens shall be sampled from representative production. Specimen sampling shall consider the material variability. Specimen size shall be determined in accordance with the referenced standard. The specimen size shall include the minimum and maximum thicknesses and depths unless specifically noted in the test method Manufacturing parameters, such as core, facing, adhesives, fasteners, and/or other SIP components, SIP configurations, and processing details, shall be identified as part of the qualification procedures. Changes in these parameters shall require an engineering evaluation or re-qualification Core joints shall not be allowed unless specifically qualified using samples manufactured with core joints The SIP assemblies shall be tested at the as-received moisture conditions. The moisture content and specific gravity of the representative facing materials and lumber shall be reported. 6.2 Racking Resistance Racking resistance of the PRS performance-rated SIPs shall be qualified in accordance with ASTM E Splines meeting the requirements shown in Figures 1 and 2 shall be used in SIP specimen fabrication A minimum of 3 full-size assemblies of each SIP configuration (wall thickness) intended for qualification shall be tested Both the maximum test load and the load at the net lateral deflection of the wall of 1/8 inch shall be reported Qualification test results for the PRS performance-rated SIPs shall conform to the test values specified in Table Axial Load Capacity January 2008 Copyright 2008 by APA Page 9 of 16

10 6.3.1 Axial load capacity of the PRS performance-rated SIPs shall be qualified in accordance with ASTM E 1803 except that the wall panel shall be loaded with an eccentricity of 1/6 the panel thickness to the interior panel. The pre-cut hole for electric box on the facing materials shall be included in the test assembly. Splines shall not be used on the edge parallel to the applied axial load of the SIP specimen A minimum of 3 full-size assemblies of each SIP configuration (wall thickness and height) intended for qualification shall be tested Both the maximum test load and the load at the net axial deformation of 1/8 inch shall be reported Qualification test results for the PRS performance-rated SIPs shall conform to the test values specified in Table Transverse Load Capacity Transverse load capacity of the PRS performance-rated SIPs shall be qualified in accordance with ASTM E The pre-cut hole for electric box on the facing materials shall be included in the test assembly and placed on the tension side of the test setup. Splines shall not be used along the test span of the SIP specimen A minimum of 3 full-size assemblies of each SIP configuration (wall thickness and height) intended for qualification shall be tested Both the maximum test load and the load at the net transverse deflection of the wall of H/240, where H is the wall height in inches, shall be reported Qualification test results for the PRS performance-rated SIPs shall conform to the test values specified in Table Lintel Load Capacity Lintel load capacity of the PRS performance-rated SIPs shall be qualified in accordance with this section For the purpose of this standard, the lintel depth of 12 inches is considered as the standard depth and the results obtained from the qualification are applicable to lintel depths of 12 inches or less A minimum of 3 specimens for each combination of lintel thickness and length shall be prepared for testing. The lintel length shall be based on those shown in Table 3. Each specimen for each combination shall be taken from a separate SIP panel to permit the assessment of the variability of the test results The SIP lintels shall be cut out from large SIP panels and fabricated with 2x SPF No. 2 Grade lumber attached to the top and bottom of the lintel with nails. The long edges (lintel length) of the core material in each specimen shall be routed out to a depth of 1-1/2 inches to accommodate the 2x lumber. The short edge of the specimens shall not include the 2x lumber and the core material shall be kept flush with the ends of the specimen. The 2x lumber shall run the full length of the specimen. January 2008 Copyright 2008 by APA Page 10 of 16

11 6.5.5 Edgewise bending tests shall be conducted in accordance with the third-point loading method of Section 18 of ASTM D 4761 and Figure 5. Load and deflection data shall be continuously recorded until failure. Load at Third Points SIP Lintel STRONGBACK 1-1/2 " Bearing 96" shown for example only. Figure 5. Example of third-point loading configuration for SIP lintel tests Test results from each specimen shall be reported to include the maximum test load and the load at the deflection limit of L/360, where L is the lintel span in inches Qualification test results for the PRS performance-rated SIPs shall conform to the test values specified in Table Durability Durability of the PRS performance-rated SIPs shall be qualified by comparing the performance of SIPs between as-received and wet-and-redry conditions per Section 15.3 of ASTM E 72 except that the specimen shall be re-dried at the final (3 rd ) cycle and tested when the assembly is re-dried One matched set (a minimum of 3 assemblies) of 4-1/2 x 8 height SIP assemblies shall be tested for racking, axial load, and transverse load for dry and wetredry Durability of the PRS performance-rated SIPs is acceptable when the results of redry assemblies is no less than 75% of that of dry (as-received) assemblies on the average result of each assembly set. 6.7 Gluebond Strength January 2008 Copyright 2008 by APA Page 11 of 16

12 6.7.1 The gluebond strength between facing and core of the PRS performancerated SIPs shall be qualified in accordance ASTM D xxxx The average load at failure shall not be less than 15 psi or the tensile strength of the core materials, whichever is larger. 7. Test Results Evaluation 7.1 Upon completion of qualification tests, all test results shall be documented by a qualified testing agency in a test report in accordance with ICC-ES AC The evaluation of the test results confirming compliance with this standard is the responsibility of the qualified testing agency and/or the qualified inspection agency. 7.3 Upon satisfactory completion of the product qualification and evaluation, all manufacturing variables shall be documented in the in-plant quality manual along with quality assurance procedures, as required in the following section, in accordance with ICC-ES AC Quality Assurance 8.1 Quality assurance of the PRS performance-rated SIPs shall follow the inplant manufacturing standard accepted by a qualified inspection agency. 8.2 Periodic re-evaluation of structural capacities of the PRS SIPs shall be conducted in accordance with the requirements of the qualified inspection agency. This re-evaluation shall be performed at the end of the first 6 months for any new plant or any new production line and shall not be longer than every 12 months for any existing plant or any existing production line. The re-evaluation may be conducted using the on-going quality assurance data from the component tests and supplemented by full-scale tests as needed. 8.3 Product Labeling All PRS performance-based SIPs shall be identified with a label or certificate of inspection issued by a qualified inspection agency. The product label shall meet the following minimum requirements: a) Manufacturer Identification (such as name or logo) b) Quality Assurance Agency Identification (such as name or logo) c) Conformance with this standard as signifying by the designation of APA/ANSI PRS d) Flame spread index and smoke development index of the core materials in accordance with Section of this standard. January 2008 Copyright 2008 by APA Page 12 of 16

13 Annex A1. Applicability Limitations (Mandatory Information) A1.1 This annex provides the limitations for PRS performance-rated SIPs based on the assumptions when the standard was developed. Applications beyond these limitations require engineering evaluation. Table 1. PRS Applicability Limitations Attribute Limitation General Building Dimension Maximum building width of 40 feet Maximum building length of 60 feet Number of Stories 2 story (above basement) Basic Wind Speed Up to 130 mph Wind Exposure Exposures B (a) (suburban/wooded) Exposures C (a) (open terrain) Ground Snow Load 70 psf maximum ground snow load Seismic Zone A, B and C (a) Building Height Maximum 35 feet Floor Floor dead load 10 psf maximum Floor live load First floor Second floor (sleeping rooms) Wall dead load Load bearing wall eave height 40 psf maximum 30 psf maximum Wall 10 psf maximum 10 feet maximum Deflection Criteria L/240 Roof Roof dead load 10 psf maximum Roof snow/live load 70 psf maximum ground snow load (16 psf minimum Roof Live Load). Ceiling dead load 5 psf maximum Roof slope 3:12 to 12:12 Rake overhang 12 inches maximum Attic live load (Limited Storage) 20 psf maximum (a) As defined by the provisions in ASCE 7. December 2007 Copyright 2007 by APA Page 13 of 16

14 Annex A2. Qualification of Facing Materials (Mandatory Information) A2.1 General This annex provides qualification requirements for facing materials to demonstrate compliance with the minimum properties specified in Table 2 of this standard. Prior to this qualification, the facing material shall be pre-qualified in accordance with PS 1, PS 2, CSA O121, CSA O151, CSA O325, or CSA O437 as required in Section For each recipe of facing materials from each supplier, a separate qualification in accordance with this annex is required. A2.2 Sampling and Specimen Preparation A minimum of 10 4 ft x 8 ft panels shall be randomly sampled from representative production by a qualified inspection agency. Each panel shall be prepared in accordance with the cutting diagram shown in Figure A2.1. A2.3 Required Tests Qualification tests shall be conducted in accordance with Figure A2.1 based on standard and as-received moisture conditions. A2.4 Data Analysis Qualification test results shall be analyzed in accordance with ASTM D Test results from the standard moisture conditions shall be used to compare with the minimum properties specified in Table 2. Test results from the as-received moisture conditions shall be used to establish the control values for quality assurance purposes unless the quality assurance tests at the panel plant or the SIP manufacturer s facility can be conducted at the standard moisture conditions. A2.5 Acceptance Criteria The facing materials shall be considered as in conformance with this standard when the following criteria are all met: a) The mean test values from the standard moisture conditions for flatwise stiffness in both along and across directions are not less than the values tabulated in Table 2. b) The 5 th percentile values with 75% confidence from the standard moisture conditions for flatwise strength and tensile strength in both along and across directions are not less than the values tabulated in Table 2. c) The mean panel density based on the oven-dry weight and over-dry volume is not less than the value tabulated in Table 2. A2.6 Quality Assurance A quality assurance program shall be established by the panel or SIP manufacturer and a qualified inspection agency in accordance with PS 1, PS 2, CSA O121, CSA O151, CSA O325, or CSA O437. The control values for small-specimen flatwise bending tests January 2008 Copyright 2008 by APA Page 14 of 16

15 shall be established based on the qualification test results at the as-received moisture conditions, as described in Section A2.4 of this annex. Figure A1. Cutting diagram for specimen preparation. January 2008 Copyright 2008 by APA Page 15 of 16

16 Figure A2.1 Detailed test requirements. January 2008 Copyright 2008 by APA Page 16 of 16