August 1, 2014 PARTIES INTERESTED IN CROSS LAMINATED TIMBERS USED AS COMPONENTS IN FLOOR AND ROOF DECKS

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1 August 1, 2014 TO: PARTIES INTERESTED IN CROSS LAMINATED TIMBERS USED AS COMPONENTS IN FLOOR AND ROOF DECKS SUBJECT: Proposed New ICC-ES Acceptance Criteria for Cross-laminated Timber Panels for Use as Components in Floor and Roof Decks, Subject AC R1(PC/MO/JF) Dear Colleague: The enclosed proposal for a new acceptance criteria is being posted on the ICC-ES web site for 30 days of public comment. Public comments will be considered in preparing a revised draft of the criteria, which we hope to present at a future ICC-ES Evaluation Committee hearing. Currently, the cross-laminated timber (CLT) is manufactured in accordance with ANSI/APA PRG 320, Standard for Performance-Rated Cross-Laminated Timber. PRG 320 is referenced in both the 2015 International Building Code (IBC) and the 2015 International Residential Code (IRC) for use of the product in floor, roof and wall applications. However, the 2015 IBC and IRC, as well as ANSI/APA PRG 320, do not provide guidance for evaluation of CLT panels for use as components in floor, roof decks, and wall applications. The intent for developing this new criteria is to establish requirements for evaluation of CLT panels for use as components in floor and roof decks, to resist out-of-plane bending and in-plane shear loads, respectively. In addition to your comments on the proposed criteria, we are particularly interested in your input on the following: 1. Panel-to-panel connection: The proposed criteria does not include provisions for panel-to-panel connections of CLT panels used as components of floor and roof decks. We are is concerned about not having requirements on the panel-to-panel connections in this criteria, since the panel-to-panel connections will affect the capacity of floor or roof decks consisting of CLT panels as components. We are seeking your input on the inclusion of panel-to-panel connection evaluation in the new criteria. 2. Fasteners and connectors: The proposed criteria does not include provisions on fasteners and connectors that are used to connect the CLT panels together and to attach CLT panels to the supporting elements. Should the proposed criteria include requirements on fasteners and connectors? Your inputs on this are appreciated.

2 2 3. Notches and penetrations: Notches and penetrations in CLT panels are not evaluated in the proposed criteria. Should the notches and penetrations in CLT panels be addressed in this new criteria? 4. Test method for in-plane shear: Section 4.4 of the proposed criteria will require that the in-plane shear of CLT panels be conducted in accordance with Annex A3 of ASTM D5456. It is understood that Annex A3 of ASTM D5456 is an alternative test method to the ASTM D143 block shear test method and for determining the horizontal shear stress in structural-size members of SCL when tested in accordance with ASTM D198 test procedures for short-span edgewise bending. We are seeking your inputs on whether Annex A3 of ASTM D5456 is a proper test method for use to conduct the in-plane shear testing since the boundary condition in Annex A3 short-span edgewise bending is different from the boundary condition of CLT panels of CLT panels used as components in floor and/or roof decks. The internal makeup of CLT (cross laminations and bonded versus unbounded joints), may also make it different with regard to this test. 5. In-plane shear stiffness: In addition to the requirement for the in-plane apparent shear strength, as noted in Section , to be determined in accordance with Annex A3 of ASTM D5456, the requirements for the in-plane shear stiffness should be included in Section of the criteria. However, Annex A3 does not provide a method to determine in-plane shear stiffness based on test results. We are seeking your input on a proper method that can be used to determine the in-plane shear stiffness of CLT panels used as components in floor and/or roof decks. 6. Deflection equation under in-plane shear loading: The current codes and code referenced design standards have deflection equations for calculating in-plane deflections of horizontal diaphragms, such as floors and/or roof decks. Those equations are applicable to the framed diaphragms. The proposed criteria does not includes provisions for the derivation of a deflection equation based on the analysis of test data. Your input will help us to develop provisions for developing deflection equation under in-plane shear load to include in the acceptance criteria. 7. Wind and seismic recognition: Evaluation of CLT panels for use as components in floor or roof decks for wind and seismic design is outside the scope of this new criteria. We are seeking your input as to whether or not the evaluation for wind and seismic design should be included in this criteria. 8. Adjustment factors for reference design properties: The proposed criteria has provisions in Section 4.5.2, addressing adjustment factors that can be used for reference design properties. Although CLT panels are similar to glued-laminated timber, we question whether those NDS adjustment factors are applicable to CLT panels. We look for your input on this issue.

3 3 9. IRC: The proposed criteria does not include reference to the IRC. Evaluation of CLT panels for use as components in floor and roof decks would require standardized load tables for use in prescriptive design. Staff request input as to the need for evaluation of CLT under the IRC. 10. Fire-retardant-treated wood (FRTW): Section of the 2015 IBC allows use of FRTW in the fabrication of CLT. We request input on testing needed to allow the use of FRTW with CLT since strength reductions in Section of the 2015 IBC are applied to FRTW used in high temperature and humidity applications. If it is of interest, please review the proposed criteria and send us your comments at the earliest opportunity. At the end of the 30-day comment period, we will post on our web site the correspondence we have received and, in memo form, the responses of our technical staff. To submit your comments, please use the form on the web site and attach any letters or other materials. If you would like an explanation of the alternate criteria process, under which we are soliciting comments, this too is available on the ICC-ES web site. Please do not try to communicate directly with any Evaluation Committee member about a criteria under consideration, as committee members cannot accept such communications. Thank you for your interest and your contributions. If you have any questions, please contact me at (800) , extension 3535, or Michael O Reardon, P.E., Regional Engineering Director, at extension You may also reach us by at es@icces.org. Yours very truly, Ping Cheng, P.E. Staff Engineer PC/sp Encl. cc: Evaluation Committee

4 (800) (562) A Subsidiary of the International Code Council PROPOSED ACCEPTANCE CRITERIA FOR CROSS-LAMINATED TIMBER PANELS FOR USE AS COMPONENTS IN FLOOR AND ROOF DECKS AC455 Proposed PREFACE Evaluation reports issued by ICC Evaluation Service, LLC (ICC-ES), are based upon performance features of the International family of codes. (Some reports may also reference older code families such as the BOCA National Codes, the Standard Codes and the Uniform Codes). Section of the International Building Code reads as follows: The provisions of this code are not intended to prevent the installation of any materials or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety. ICC-ES may consider alternate criteria for report approval, provided the report applicant submits data demonstrating that the alternate criteria are at least equivalent to the criteria set forth in this document, and otherwise demonstrate compliance with the performance features of the codes. ICC-ES retains the right to refuse to issue or renew an evaluation report, if the applicable product, material, or method of construction is such that either unusual care with its installation or use must be exercised for satisfactory performance, or if malfunctioning is apt to cause injury or unreasonable damage. NOTE: The Preface for ICC-ES acceptance criteria was revised in July 2011 to reflect changes in policy. Acceptance criteria are developed for use solely by ICC-ES for purposes of issuing ICC-ES evaluation reports.

5 P a g e 2 PROPOSED ACCEPTANCE CRITERIA FOR CROSS-LAMINATED TIMBER PANELS FOR USE AS COMPONENTS IN FLOOR AND ROOF DECKS INTRODUCTION 1.1 Purpose: The purpose of this acceptance criteria is to establish requirements for evaluation of cross-laminated timber (CLT) panels to be recognized for use as components in floor and roof decks in an ICC Evaluation Service, LLC (ICC-ES), evaluation report under the 2015, 2012 and 2009 International Building Code (IBC). Bases of recognition are IBC Section , 2015 IBC Sections 202, (Type III Construction), (Type IV Construction), (Cross-laminated timber floors), (Cross-laminated timber roofs), 2303 (Minimum Standards and Quality), and (Structural glued cross-laminated timber) and 2012 and 2009 IBC Sections (Type III Construction), (Type IV Construction), (Floors), (Roofs), and 2303 (Minimum Standards and Quality for Wood) The reason for the development of this criteria is that the codes and the code referenced design standards do not include sufficient provisions for the evaluation of CLT panels for use as components in roof and floor decks in Type III (interior floor decks only), IV or V construction (IBC). 1.2 Scope: This criteria is applicable to the evaluation of floor and roof decks consisting of CLT panels, as components, qualified in accordance with ANSI/APA PRG Codes and Referenced Standards:

6 P a g e , 2012, 2009 International Building Code (IBC), International Code Council ASTM D (-09 for the 2012 IBC and -05a for the 2009 IBC), Standard Specification for Evaluation of Structural Composite Lumber Products, ASTM International ASTM E119-12a (-08a for the 2012 IBC and -07 for the 2009 IBC), Standard Test Methods for Fire Tests of Building Construction and Materials, ASTM International ASTM E (Reapproved 2009), Standard Test Method for Conducting Transverse and Concentrated Load Tests on Panels used in Floor and Roof Construction, ASTM International ANSI/APA PRG , Standard for Performance-Rated Cross-Laminated Timber, American National Standard Institute/APA The Engineered Wood Association ANSI/AWC NDS-15 (-12 for the 2012 IBC and -05 for the 2009 IBC), National Design Specification for Wood Construction with 2012 Supplement, American National Standard Institute/American Wood Council AWC SDPWS-15 (-08 for the 2012 IBC and the 2009 IBC), Special Design Provisions for Wind and Seismic, American Wood Council. 1.4 Definitions: Cross-laminated Timber (CLT): A prefabricated engineered wood product consisting of not less than three layers of solid-sawn lumber or structural composite

7 P a g e lumber (SCL) where the adjacent layers are cross-oriented and bonded with structural adhesive to form a solid wood element CLT Lamination: An individual piece of solid-sawn lumber or structural composite lumber (SCL) CLT Layer: All laminations on one side of a face bondline for panel face or all laminations between two adjacent bondlines for others CLT Floor and Roof Deck: Floor or roof deck assembly consisting of CLT panels as components, supporting in-plane shear loads and out-of plane transverse (e.g. gravity or wind uplift) loads CLT Panel: A single CLT billet Parallel Layer: All laminations oriented parallel to the major strength direction in CLT panels Perpendicular Layer: All laminations oriented parallel to the minor strength direction in CLT panels CLT Layup: an arrangement of layers in a CLT panel Face Bondline: Refer Section 3.2 of ANSI/APA PRG Edge Bondline: Refer Section 3.2 of ANSI/APA PRG Major Strength Direction: Parallel to the general orientation of wood grain in the laminations of the top and bottom face layers of the CLT panel; also referred to as the parallel direction Minor Strength Direction: Perpendicular to the major strength direction; also referred to as the perpendicular direction.

8 P a g e BASIC INFORMATION 2.1 General: The following information shall be submitted: Product Description: Cross-laminated Timber (CLT) Panels: Complete information concerning CLT panel grades, layups, dimensions and dimensional tolerances, squareness, straightness, and the manufacturing process CLT Laminations: Complete information concerning sawn lumber grades, species and species groups, sizes, minimum specific gravity, moisture content and, end joints in sawn lumber Bondline: Complete information concerning the face bondline and edge bondline Adhesives: Adhesive specifications are to include the type, class, adhesive spread rate, brand and manufacturer name, and ICC-ES evaluation report number (if applicable) Installation Instructions: Installation details, limitations, procedures and handling instructions Packaging and Identification: A description of the method of packaging and field identification of the cross-laminated timber panels. Identification provisions shall include the manufacturing layup combination, grade, sizes, and name of the crosslaminated timber panel fabricator, evaluation report number and the name or logo of the inspection agency. The identification shall be visible after the CLT panel is installed.

9 P a g e Field Preparation: A description of the method of field-cutting, application and finishing of the CLT panels. 2.2 Testing Laboratories: Testing laboratories shall comply with Section 2.0 of the ICC-ES Acceptance Criteria for Test Reports (AC85) and Section 4.2 of the ICC-ES Rules of Procedure for Evaluation Reports. 2.3 Test Reports: Test reports shall comply with the ICC-ES Acceptance Criteria for Test Report (AC85). 2.4 Product Sampling: CLT panels shall be sampled in accordance with Sections 3.1, 3.3, and 3.4 of AC85. CLT panels sampled shall be representative of the standard manufactured CLT panel products to be evaluated. 3.0 TEST AND PERFORMANCE REQUIREMENTS 3.1 CLT Panel General Requirements: CLT panels shall be manufactured and qualified in accordance with ANSI/APA PRG CLT Panel in Floor and Roof Deck Evaluations: The CLT panels for use as components in floor and roof decks shall be tested and analyzed for both out-off plane transverse and in-plane shear loading in accordance with Section 4.0. A description of CLT panels used in the construction of test specimens shall include the CLT panel grades, layups, thickness, width, length, installation orientation of the CLT panels. 4.0 TEST METHODS AND ANALYSIS REQUIREMENTS: 4.1 General:

10 P a g e Where otherwise specified in this criteria, ten tests of identical CLT panel specimens consisting of each CLT panel grade/layup/thickness combination for which recognition is sought are required Factors of safety are dependent on the consistency of materials, the range of test results and the load deformation characteristics of the panel. A minimum safety factor of three is applied to the average ultimate load determined in accordance with Section of this criteria when determining allowable loads The average ultimate load shall be determined based on the ultimate loads of ten tests, regardless of the variations of test results. Where tests are not conducted to failure, the highest load achieved for each test will be assumed as ultimate load Where allowable loads are limited by the established fastener values or deflection limitations, the lower value shall control For in-plane shear load testing, the testing shall be constructed in accordance with Annex A3 of ASTM D5456. The CLT panel specimens shall be a single layer of either 3-ply or 5-ply, having minimum panel size of 16 inches by 72 inches (406 by 1829 mm). The loading apparatus, application of loading, duration of load application and deformation measurement shall be in accordance with Annex A3 of ASTM D For out-of plane transverse load testing, the deformation measurement device shall comply with Section 10.4 of ASTM E2322 and deflection readings are to be taken at mid-span, within 3 inches (76 mm) of each edge and at the center of the panel width. For CLT panel widths less than 24 inches (610 mm), the edge readings shall be taken at a distance from each diaphragm edge not more than ten percent of the diaphragm s

11 P a g e width. CLT panels tested over a double span are to have the same three deflection readings taken at the expected maximum deflection point based on analysis. 4.2 Testing Floors: Transverse Load: Uniform Load: Uniform load tests shall be conducted in accordance with the bag method specified in Section of ASTM E2322 or the vacuum chamber method of Section of ASTM E Gravity Load: Gravity load testing, if required, shall be conducted in accordance with ASTM Practice E196, as noted in Section of ASTM E Two Point Load: Two point load testing method, if used, shall be in accordance with Section of ASTM E Allowable loads shall be based on the lower of the following: Allowable loads are determined under Sections through Allowable loads are determined based on the loads at the deflection requirements in IBC Table Concentrated Live Load: Concentrated load tests for floors are necessary for loads specified in IBC Section , as applicable Allowable loads for floors are determined under Sections through The deflection of floor shall comply with the deflection requirements in IBC Table Deflection readings are taken at mid-span at each edge and the center of the test assemblies.

12 P a g e Testing Roof Decks: Transverse Load: Uniform Load: Uniform load tests shall be conducted in accordance with the bag method specified in Section of ASTM E2322 or the vacuum chamber method of Section of ASTM E Gravity Load: Gravity load testing, if required, shall be conducted in accordance with ASTM Practice E196, as noted in Section of ASTM E Two Point Load: Two point load testing method, if used, shall be in accordance with Section of ASTM E Allowable loads shall be based on the lower of the following: Allowable loads are determined under Sections through Allowable loads are determined based on the loads at the deflection requirements in IBC Table Concentrated Live Load: Concentrated load tests are necessary for concentrated live loads specified in IBC Section , as applicable Allowable loads for roof decks are determined under Sections through Deflection of roof decks shall comply with the deflection requirements in IBC Table Deflection readings are taken at mid-span at each edge and the panel center For roof decks, water accumulation or water ponding shall be addressed in accordance with IBC Section

13 P a g e For roof decks evaluated under the IBC, roof deck spans must be evaluated for uniform dead load combined with the 300-pound (1334 N) concentrated design live load required by IBC Section and Table When compliance is demonstrated by load testing, the allowable concentrated load determined in accordance with Sections through shall exceed the required 300-pound concentrated design live load, with the required safety factor also applied to the uniform dead load. At the design concentrated live load and uniform dead load, the tested panels shall comply with the deflection limitations noted in IBC Table In-plane Shear Load Tests: The ultimate shear strength and shear stiffness of CLT panels used as components in horizontal diaphragm assemblies, for which recognition is sought, shall be established by testing in accordance with this section Test Method: The short-beam edgewise bending test method specified in Annex A3 of ASTM D5456 shall be used to conduct the in-plane static load tests. The test procedure shall be in accordance with Annex A3 Section A3.3 of ASTM D Sample Size: The minimum sample size shall be in accordance with Annex A3 Section A3.2.1 of ASTM D5456, which is Size of Test Specimen: The size of test specimen shall be in accordance with Annex A3 Sections A3.2.3 through A Configurations of Test Specimens: Depending on the orientation of the major strength direction in respect to the loading direction, the major strength direction of the CLT panels may be parallel to or perpendicular to the loading direction. The in-

14 P a g e plane static load tests shall be conducted on each of the CLT panel configurations for which recognition is sought Conditioning of Test Specimen: The test specimens shall be conditioned in accordance with Annex A3 Section A3.2.2 of ASTM D5456 prior to testing Analysis: Analysis of test results, sealed by a registered design professional, shall be provided to determine the following: The apparent shear strength shall be determined in accordance with Annex A3 Section A3.4.1 of ASTM D5456 for each test specimen The characteristic value shall be determined in accordance with Annex A3 Section A3.4.2 of ASTM D The allowable design shear stress shall be determined in accordance with Annex A3 Section A3.4.3 of ASTM D The apparent shear stiffness shall be determined in accordance with Test Report: The test report shall comply with the ICC-ES AC85 and Annex A3 Section A3.4 of ASTM D Other Considerations: Fire Resistance: CLT panels used as components in floor and roof decks and requested to be recognized for fire performance shall be tested in accordance with ASTM E119 and shall be rated for fire resistance in accordance with the results and conditions of such tests Adjustment Factors for Reference Design Properties:

15 P a g e Load Duration Factor, C D : Load duration factor shall be as specified in Section of the NDS for diaphragms consisting of CLT panels used as floor and roof decks. Load duration factor does not apply to the modulus of elasticity and the compression perpendicular to grain of CLT panels Time-dependent Deformation (Creep) Factor, K er : The creep factor, K er, shall be 1.5 as specified in Section of NDS for diaphragms consisting of CLT panels used as floor and roof decks under dry service conditions when the moisture content in lumber in service is less than 16%, as in most covered structures Temperature Factor, C t : The temperature factor shall be as specified in Section of the NDS, when diaphragms consisting of CLT panels used as floor and roof decks experience sustained exposure to elevated temperature up to 150 o F Wet Service Factor, C M : The wet service factor, C M, shall be 1.0 for diaphragms consisting of CLT panels used in dry service conditions where the moisture content in lumber in service is less than 16 percent, as in most covered structures. 5.0 QUALITY CONTROL 5.1 The CLT panels used in diaphragms shall be manufactured under an approved quality control program with inspections by ICC-ES or an inspection agency that has a contractual relationship with ICC-ES. 5.2 Quality documentation complying with the ICC-ES Acceptance Criteria for Quality Documentation (AC10) shall be submitted for each facility manufacturing or labeling CLT panel products that are recognized in the ICC-ES evaluation report.

16 P a g e A qualifying inspection shall be conducted at each facility manufacturing or labeling CLT panel products when required by the ICC-ES Acceptance Criteria for Inspections and Inspection Agencies (AC304). 6.0 EVALUATION REPORT RECOGNITION 6.1 Basic information required by Section 2.1 of this criteria, including diaphragm assembly and component description, installation procedures, and packaging and identification information 6.2 Reference design values with the associated adjustment factors for the out-ofplane loading for each CLT panel configuration, based on analysis of data as described in Sections 4.2 and 4.3 of this criteria. 6.3 Reference design values with the associated adjustment factors for in-plane (lateral) loads, based on analysis of data described in Section 4.4 of this criteria. 6.4 Analysis of horizontal diaphragm consisting of CLT panels as components in floor or roof decks shall comply with applicable requirements in Chapters 16, 17, and 23 of the IBC. 6.5 The evaluation report is to include a statement that the panel-to-panel connections, fasteners, connectors, and notches and penetrations in CLT panels have not been evaluated and are out of the scope of the evaluation report. 6.6 The evaluation report is to include a statement that CLT panels used as components in roof and floor decks have not been evaluated for wind and seismic design and are out of the scope of the evaluation report.

17 P a g e The evaluation report is to include a statement that the CLT roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with applicable provisions of IBC Chapter The evaluation report is to include a statement that the CLT panels used as components in floor and roof decks are limited to the use in dry service conditions, i.e., the moisture content in the wood is less than 16%. 6.9 The evaluation report is to include a statement that the special inspection shall be conducted in accordance with the applicable requirements of Sections 1704 and 1705 of the IBC The evaluation report is to include a statement that allows the CLT panels for use as components in floor and roof decks under the IRC when engineered design is submitted in accordance with Section R