WOODWORKS WEBINAR - JUNE 14, 2012

Transcription

1 W HAT W HEN W HY

2 WOODWORKS WEBINAR - JUNE 14, 2012 Catherine Marx Kaake, P.E, CFM Senior Director, Engineered & Framing Markets Special Thanks to: WoodWorks SPIB AWC SBCA NAHB Anthony Forest Products Weyerhaeuser Others

3 The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

4 COPYRIGHT MATERIALS This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. The Wood Products Council 2011

5 LEARNING OBJECTIVES At the end of this program, participants will be able to: Assess the potential impact of the new design values Describe the process for establishing design values Discover the resources available and determine how to implement the new design values Prepare for future design value changes

6 TODAY S TOPICS WHAT MARKET IMPACTS WHY WHEN is affected (and not) of new design values background future

7 W HAT IS AFFECTED

8 DESIGN VALUE PROCESS Determined by regional agencies accredited by the American Lumber Standard Committee (ALSC) ASTM standards provide the procedures Testing plans and results are certified by the ALSC Board of Review after review by the USDA Forest Service

9 RULES-WRITING AGENCIES

10 SPIB FIRST TO PROPOSE DESIGN VALUES September 2011 Proposed new design values for all grades and sizes Visually graded Southern Pine dimensional lumber Based on testing only No.2 2x4s in bending & tension January 2012 Board of Review American Lumber Standard Committee ALSC Board of Review approved new design values But only some of the proposed grades & sizes June 2012 Effective date for this first set of grades & sizes

11 PRODUCER & CUSTOMER CONCERNS Process and Timing Magnitude of the changes

12 MAGNITUDE OF THE CHANGES PROPERTY CHANGE (approximate) Bending -30% Tension -20% Compression -35% Modulus of Elasticity -200,000 psi Shear Compression Perpendicular Specific Gravity No Change No Change No Change 12

13 MARGIN OF SAFETY FOR IN-MARKET LUMBER Long history of reliable performance Conservatism in design process Existing or in-progress structures do not need re-evaluation Time to complete additional testing

14 TRANSITION PERIOD: JAN. TO JUNE 2012 Provide an orderly transition Time to manage design value changes Minimize project delays Minimize supply chain disruptions Producers Listened to customers Explored alternate grades Many customers successfully transitioned with minimal disruption to their businesses

15 SUPPLEMENT NO.9 ON

16 EFFECTIVE JUNE 1, 2012 SPECIES: Southern Pine & Mixed Southern Pine PRODUCT: Dimension Lumber SIZES: 2x2s through 4x4s GRADES: Visual Grades No.2 Dense and lower No.2, No.3, Stud, Construction, Standard, Utility No.2 Dense and No.2 NonDense SP Other grades & sizes pending additional testing

17 A LOOK AT THE NEW VALUES - ON Southern Pine & Mixed Southern Pine 1 Reference Design Values values in psi (pounds per square inch) Bending F b Tension Parallel to Grain F t Shear Parallel to Grain F v 2 Compression Perpendicular to Grain F c 2 Compression Parallel to Grain F c Modulus of Elasticity E 2" to 4" Thick, 2" to 4" Wide Only No.2 Dense ,500,000 No ,400,000 No.2 N ,200,000 No.3 & Stud ,200,000 Construction ,300,000 Standard ,200,000 Utility ,100,000 1) No.2 Dense and No.2 NonDense grades apply to Southern Pine, but not Mixed Southern Pine. 2) Shear and Compression Perpendicular-to-Grain design values have not changed.

18 ALSO AFFECTED AT THIS TIME Products based on the new design values for dimension lumber: Grades: No.2 Dense and lower Sizes: 2 to 4 thick, 2 to 4 wide Prime Dimension No.2 Prime but not No.1 Prime 2x4 Prime but not larger sizes

19 FINGER-JOINTED STUDS ALSO AFFECTED Stud and No.2 grades 2x4, but not 2x6, Finger-Jointed Studs

20 AFFECTED IN THE NEAR FUTURE Other visual grades & sizes of SP lumber Pending results of additional testing Changes are expected

21 NO CHANGE FOR OTHER SP LUMBER PRODUCTS Mechanically graded lumber Timbers Glued laminated beams Special products Flooring Finish Paneling Radius Edge Decking

22 GET SIMILAR LOAD-CARRYING CAPACITIES Specify a larger size Specify a higher visual grade Specify mechanically graded lumber with similar design values

23 MECHANICALLY GRADED LUMBER Machine Stress Rated (MSR) 750f-1.4E through 3000f-2.4E Machine Evaluated Lumber (MEL) M-5 through M-42 Increased demand and production Supplement No possible MSR grades 38 possible MEL grades

24 POSSIBLE SUBSTITUTES FOR 2X4 NO.2 2x6 No.2 Southern Pine 2x4 No.1 NonDense or better SP visual grades 2x4 MSR or MEL Southern Pine grades

25 SOME POSSIBLE MSR/MEL SUBSTITUTES Grade Bending F b Southern Pine MSR & MEL Reference Design Values values in psi (pounds per square inch) Tension Parallel to Grain F t Shear Parallel to Grain F v Compression Perpendicular to Grain F c Compression Parallel to Grain F c Modulus of Elasticity E Machine Stress Rated (MSR) 1450f 1.3E ,300, f 1.5E ,500, f 1.5E ,500, f 1.6E ,600, f 1.7E ,700, f 1.5E ,500, f 1.7E ,700,000 Machine Evaluated Lumber (MEL) M ,600,000 M ,500,000 M ,600,000 M ,400,000 M ,700,000 Not all of the possible MSR and MEL grades will be produced. The marketplace will eventually determine the most common grades. 1500f-1.6E MSR and M-38 MEL are the closest direct substitutes for the old design values associated with No.2 2x4s.

26 M ARKET IMPACTS

27 AFFECT EXISTING HOMES No Only apply to new construction Existing homes had to meet building code requirements enforced at time of construction

28 IMPACT ON ROOF & FLOOR TRUSSES Most common truss species Uses 15-20% of Southern Pine lumber produced No.2 2x4s most common Impacts mitigated by design process & grade substitution

29 IMPACT ON JOISTS, RAFTERS & HEADERS Minimal impact Few 2x4s used for: Joists Rafters Headers

30 IMPACT ON OUTDOOR DECKS 40% of Southern Pine lumber produced is treated Most common application In general, minimal impact Decking not affected Joists & beams not affected 2x2s through 4x4s IRC requires minimum 6x6 posts Bracing Railing system

31 IMPACT ON WALL PLATES - CONVENTIONAL Minimal impact Compression perpendicular-to-grain design values have not changed

32 IMPACT ON WALL PLATES ENGINEERED Could be impacted If performance is governed by property with a new design value Top plates in bending End posts for shearwalls Diaphragms chords

33 IMPACT ON STUDS CONVENTIONAL No change based on IRC Section R602.2 Prescriptive requirement No change based on IBC Section 2308 Conventional Light-Frame Construction

34 IMPACT ON STUD TABLES ENGINEERED Change for tall studs >10 New design values for studs do not have the necessary strength and stiffness

35 IMPACT ON STUD TABLES ENGINEERED Change in species-specific tables for resisting wind loads in 2012 Wood Frame Construction Manual Get WFCM Addendum at

36 W HAT ABOUT CODES

37 HOW ARE DESIGN VALUES IMPLEMENTED Reference design values certified by ALSC Board of Review American Wood Council publishes in Supplement to the National Design Specification Get NDS Addendum at

38 PRESCRIPTIVE CODE AMENDMENTS

39 WHEN WILL NEW VALUES BE ENFORCED Can vary by jurisdiction AWC provides changes ICC has notified regulators Southern Pine users should begin using the new design values and revised span tables for new construction if they haven t done so already.

40 W HY CHANGES

41 BACKGROUND Design values changed multiple times Based on available test data New technology Changing resources First significant tests in 1920s Small clear specimens Last major change in 1991 Full-size commercial lumber

42 N.A. IN-GRADE TESTING PROGRAM Began in 1977 Major grading agencies, in cooperation with the USDA Forest Products Lab Required modified and new ASTM Standards

43 ASTM D-1990 Standard Practice for Establishing Allowable Properties for Visually-Graded Dimension Lumber from In-Grade Tests of Full-Size Specimens Requires a minimum of two grades and three widths in order to model grade and size performance Recommends resource monitoring

44 SPIB S ANNUAL RESOURCE MONITORING SPIB developed a resource monitoring program with assistance from the USDA Forest Products Lab Began in 1994 Most tested species

45 WHY REVISE DESIGN VALUES NOW In June 2010, SPIB was notified of lower-than-expected bending values observed during testing SPIB considered this information in conjunction with trends in their annual resource monitoring SPIB proposed plan for initial testing of full-size 2x4 No.2 lumber

46 INITIAL TEST PROTOCOL Based on In-Grade test procedures in ASTM D1990, the consensus standard for developing design values Approved by the ALSC Board of Review SPIB worked with Timber Products Inspection to implement the test plan SPIB analyzed the data and submitted proposed design values to the ALSC Board of Review

47 SOUTHERN PINE SAMPLING REGIONS

48 PROPERTIES TESTED Bending and MOE Tension Lots of other data Dimensions Knots Pith Specific Gravity Moisture Content Etc.

49 Frequency DESIGN VALUES BASED ON TEST DATA Reference Design Value 40 5 th Percentile Average Bending Stress (psi) Relationship between the average, 5 th percentile and design value for adjusted SPIB No.2 2x4 Modulus of Rupture data

50 LOWEST PIECES CONTROL DESIGN VALUES Did the weakest pieces come from one or two mills or regions No Bending: the 17 weakest pieces came from 9 different regions and 13 different mills Tension: the 18 weakest pieces came from 8 different regions and 14 different mills Not isolated to certain mills or regions

51 WHAT CHANGED SPIB did not specifically study Many variables can affect strength Change in the resource mix Change in manufacturing

52 W HAT IS NEXT

53 SOUTHERN PINE TESTING CONTINUES Completion of testing of minimum cells for a full In-Grade analysis: Grades: Sizes: No.2, Select Structural 2x4, 2x8, 2x10 Almost 7,000 pieces of full-size commercial lumber will be tested

54 PROPERTIES BEING TESTED Bending and MOE Tension Compression

55 W HEN

56 OTHER SOUTHERN PINE GRADES & SIZES SPIB plans to submit proposed new design values in time for consideration by the ALSC Board of Review at their meeting scheduled in October 2012 When will the ALSC Board of Review make a decision When will the next new design values become effective

57 WHAT APPLICATIONS WILL BE MOST AFFECTED Joists & Rafters Headers & Beams Roof & Floor Trusses Outdoor Decks Larger sizes Higher grades

58 WHAT ABOUT OTHER SPECIES Southern Pine first for full In-Grade testing Other species in different stages Will require destructive tests every 3 years SP will continue to be tested on an annual basis

59 ADDITIONAL INFORMATION Questions & Answers SP Design Values SP Span Tables SP Product Uses SP Grading Rules Codes and Standards

60 SUMMARY Assess the potential impact of the new design values Describe the process for establishing design values Discover the resources available and determine how to implement the new design values Prepare for future design value changes

61 QUESTIONS This concludes The American Institute of Architects Continuing Education Systems Course Cathy Kaake Wood Products Council

62 SOUTHERN PINE REMAINS STRONG, DEPENDABLE Higher-strength visual material still available Increasing supply of mechanically graded lumber One of the best construction products Provides great value in a wide variety of applications Productive and sustainable forests Grown and manufactured in the U.S. South

63 SIZER Gravity Design Includes customizable materials database SHEARWALLS Lateral Design (Wind and Seismic) Design Office Includes free electronic copy of the NDS and SDPWS AWC / AITC members receive 10% discount CONNECTIONS Fasteners woodworks-software.com All values updated to conform to new southern pine design values as of June 1, 2012