i 

### REVISED **TECHNICAL REPORT Measuring Formaldehyde Emissions from Low Emitting Hardwood Plywood**  **Panels under Different Conditions of Temperature and Relative Humidity** 

**prepar ed**  **fo r**  **U.S. Environmental Protection Agency Office of Pollution**  **Prevention and Toxics National Program Chemicals Division** 

**under Contract EP**  **- W**  **- 09**  **- 024**  **Work Assignment 3**  **- 03** 

**by Battelle**  **Columbus, Ohio August 28**  **, 201 3** ii 

### Ack**nowledgments** The work described in this report was conducted by Battelle under the direction of the U.S. Environmental Protection Agency through Work Assignments 2 - 07 and 3 - 03 of EPA Contract EP - W - 09 - 024.iii 

### Contents Acknowledgements ................................ ................................ ................................ ....................... ii List of Abbreviations ................................ ................................ ................................ .................... v Chapter 1 Executive Summary ................................ ................................ ................................ ...... 1 Chapter 2 Background ................................ ................................ ................................ ................... 3 Chapter 3 Test Design and Procedures ................................ ................................ .......................... 5 3.1 Project Goals and Exp erimental Design ................................ ................................ ............... 5 3.1.1 Large/Small Chamber Test Comparison ................................ ............................... 5 3.1.2 Small Chamber Emissions Testing ................................ ................................ ....... 6 3.2 Test Materials ................................ ................................ ................................ .................... 8 3.3 Experimental Methods ................................ ................................ ................................ .......... 8 3.3.1. Large Chamber Tests ................................ ................................ ............................ 8 3. 3.2 Small Chamber Tests ................................ ................................ ............................ 8 3.3.3 Chromotropic Acid Analy sis ................................ ................................ ................. 9 Chapter 4 Quality Assurance/Quality Control ................................ ................................ ............. 1 1 4.1 Chamber Test Conditions ................................ ................................ ................................ ... 11 4.2 Chromotropic Acid Calibration ................................ ................................ .......................... 11 4.3 Chamber HCHO Background ................................ ................................ ............................. 12 Chapter 5 Statistical Methods ................................ ................................ ................................ ...... 13 5.1 L arge/Small Chamber Test Comparison ................................ ................................ ............. 13 5.2 Small Chamber Emission Tests ................................ ................................ .......................... 13 Chapter 6 Test Results ................................ ................................ ................................ ................. 14 6.1 L arge/Small Chamber Comparison ................................ ................................ .................... 14 6.2 Small Chamber Emissions Tests ................................ ................................ ......................... 15 6.2.1 Effect of Resin Ty pe on HCHO Emissions ................................ ......................... 16 6.2.2 Effect of Temperature on HCHO Emissions ................................ ....................... 19 6.2.3 Effect of Relative Humidity on HCHO Emissions ................................ ............. 20 6.2.4 Characterization of Measurement Variability Inherent to Small Chamber Testing

................ ............................................................................................................. 20 Chapter 7 Summary

and Conclusions ................................ ................................ .......................... 21 Chapter 8 References ................................ ................................ ................................ ................... 22 Appendix A ................................ ................................ ................................ ................................ 24 Appendix B ................................ ................................ ................................ ................................ .. 29iv 

### Tables Table E - 1. Comparison of HCHO Emissions of Three Hardwood Pl ywood Panel Types at Lowest and Highest Temperature and Relative Humidity Conditions ................................ ........... 2 Table 1. Test Matrix and Order of Testing for Small Chamber Tests. ................................ ........... 7 Table 2. Results of Large/Small Chamber Comparison with ULEF - UF HWPW ....................... 14 Table 3. Test Conditions and HCHO Results from Small Chamber Tests ................................ ... 15 Table 4. Estimate s and Standard Errors from Regression Model ................................ ................ 18 Table 5. Summary

of Temperature and Relative Humidity Effects on Formaldehyde Emissions from Three Ty

pes of Hardwood Ply

wood a ................................ ................................ ................... 18 Table 6. Comparison of HCHO Emissions of Three Hardwood Ply wood Panel Ty

pes at Lowest and Highest Temperature and Relative Humidity Conditions ................................ ...................... 22 

### Figures Figure 1. HCHO Emissions vs. RH for T=25 °C and T=30 °C ................................ ................... 16v 

### List of Abbreviations ASTM ASTM International, formerly American Society for Testing and Materials ATCM A irborne T oxic C ontrol M easure °C degrees Celcius CARB California Air Resources Board EPA U.S. Environmental Protection Agency HCHO formaldeh yde HWPW hardwood pl ywood m 2 meters squared m 3 meters cubed MDF medium density fiberboard  g micrograms  g/mL micrograms per milliliter mL milliliters MUF melamine - urea - formaldehyde NAF no added formaldeh yde NAF - acryl ic no - added formaldeh yde

– acryl ic resin PB particleboard pMDI poly

meric diphenylmethane diisocyanate ppm parts per million RH relati ve humidity SD standard deviation T temperature TPC third party certifier TSCA Toxic Substances Control Act ULEF ultra low - emitting formaldehyde ULEF - UF ultra low - emitting formaldehyde - urea - formaldeh yde ULEF - P F ultra low - emitting formaldehyde - phenol - formaldehyde1 

### Chapter 1 **Executive Summary** In July of 2010 , the Formaldehyde Standards for Composite Wood Products Act, or Title VI of the Toxic Substances Control Act (TSCA) , was signed into law . The statute establishes formaldeh yde emission standards for hardwood ply wood (HWPW) , medium density fiberboard ( MDF ) , and particleboard (PB) sold, supplied, offered for sale, or manufactured in the United States. These emission standards are identical to the Phase 2 standards established by the California Air Resources Board’s (CARB) Airborne Toxic Control Measure (ATC M), which applies to products offered for sale, supplied, or manufactured for use in California. TSCA Title VIrequires EPA to promulgate regulations implementing the emission standards as well as a number of other provisions. The statute also specifical ly directs EPA to consider provisions for ultra low - emitting formaldehyde (ULEF) resins and no - added formaldeh yd e (NAF) resins . Both TSCA Title VIand the CARB ATCM require formaldehyde emission testing to be conducted quarterl y using the ASTM, International (formerly American Society

for Testing and Materials (ASTM)) E1333 large chamber method or ASTM D6007 small chamber method. The CARB ATCM requires manufacturers of the regulated wood products to demonstrate compliance with the emission stand ards by having their product emission tests and quality control processes certified by a third - party certifier (TPC). Under the CARB ATCM , m anufacturers who use NAF and ULEF resins may qualify for reduced testing requirements and/or an exemption from TPC certification requirements , with renewal of that status required every two years . Under both CARB ATCM and TSCA Title VIdefinitions, a NAF composite wood product cannot incorporate a resin made with formaldehyde, and a ULEF composite wood product is one made from resins that may contain formaldehyde, but emit it at particularl y low levels as specified in the definition s . Recent testing has indicated that some ULEF composite wood products may have significantl y increased formaldeh yde emissions when the temperature (T) and/or relative humidity (RH) are higher than the standard conditions ( i.e., 25 degrees Celsius ( °C ) and 50 %RH ) required in the ASTM E1333 and D6007 test methods . Consequently , EPA initiated testing to assess the effect of elevated T and RH conditions on formaldehyde emissions from NAF and ULEF composite wood products. Specifically , formaldehyde emissions from HWPW panels made with NAF acryl ic , ULEF - PF (phenol - formaldeh yde), and ULEF - UF (urea - formaldehyde) resins w ere determined using standard methods by a CARB - approved TPC laboratory at several T and RH condition s , with sufficient repetition to assess the consistency of the test results. Inaddition t o testing at the standard T/RH conditions, each HWPW ty pe (i.e., HWPW made with the three different resins) was tested at 25 ° C with 70 and 85 %RH, and at 30 ° C with 50, 70, and 85 %RH. At each T/RH condition three emission tests were conducted on each HWPW ty pe simultaneously using the ASTM small chamber (D6007) method. The test results were evaluated to determine the effect of T and RH on the formaldehyde emissions of HWPW panels made with each of the three resins . The anal ys is of test data showed that formaldeh yd e emissions from the ULEF - UF panel s increased with increasing T and RH , and that this relationship was statistically significant with2

respect to the panels selected for the experiment (see Appendix for further details on the statisti cal analyses) . For the NAF - acrylic panels, the anal ys is showed a small increase in formaldeh yde emissions with increasing T and RH, but this relationship was not statistically significant with respect to th e panels selected for the experiment. Formaldehyde emissions for the ULEF - PF panels decreased slightly with increased T and RH, and this relationship was found to be statistically

sign i ficant with respect to the panels selected for the experiment. For eac h resin ty pe , testing at all T and RH conditions was conducted with samples from the same panel s , so that any effects specific to the panel s (e.g., location in stack, manufacturer’s lot) appl y equall y to all observations across T and RH . Time (i.e., produ ct aging during the sequence of tests) is also unlikely

to have influenced the results, since the T and RH conditions used in testing were in random order. Table E - 1 illustrates the results of this study . For each panel type used in the study, Table E - 1 reports the estimated formaldehyde ( HCHO ) emission at the standard testing condi tions (25 °C/50 %RH) and at the highest T and RH conditions (30 ° C/85 %RH) , based on the statistical anal ys is of all test results for that panel type. Table E - 1 also shows the change in HCHO emissions between the standard testing conditions and the highest conditions. **Table E -**  **1. Comparison of**  **Estimated HCHO E**  **missions of Three Hardwood Plywood Panel**  **Types at**  **L owest and**  **H ighest**  **T emperature and**  **R elat** **ive H**  **um idity**  **C onditions**  **HWPW Panel Type**  **HCHO Emission** 

**at 25 °C/50 %RH (ppm)**  **HCHO Emission**  **at 30 °C/85 %RH (ppm)**  **Change**

**(ppm)** ULEF -UF 0.0471 0.1230 0.0759 ULEF - PF 0.0356 0.0333 - 0.0023 NAF - acrylic 0.0238 0.0290 0.0052 Note: TSCA Title VI requires no test result higher than 0.05 ppm (under standard T and RH conditions) for HWPW made with ULEF resins to qualify for a TPC exemption. Table E - 1 shows that the combined effect of T and RH resulted in an increase in formaldeh yde emission of the ULEF - UF panels by 0.0759 parts per million (ppm) between the standard conditions of 25 °C/50 %RH and the test conditions of 30 °C/85 %RH. The HCHO emissions from the ULEF - PF panels decreased by 0.0023 ppm between the standard conditions and 30 °C/85 %RH. The HCHO emissions from the NAF - acryl ic panels increased by 0.0052 ppm between the standard conditions and the test conditions of 30 °C/85 %RH. The results of this study

showed that HWPW panels made with ULEF - UF resin had a greater response to T and RH than either the NAF - acryl ic or the ULEF - PF panels. Statistical tests showed that the response of HCHO emission to T and RH for the ULEF - UF panels used in the experiment was significantly different from that of the NAF - acrylic and ULEF - PF panels . The observed emission behavior of the three different ty pes of HWPW in this study is consistent with the nature of the resins used in their manufacture. The minimal emission s and absence of T and RH effects with th e NAF - acryl ic panels reflect the absence of HCHO in the NAF resin, and the differences in emission s and T and RH effects for the ULEF - UF and ULEF - PF panels are consistent with the greater chemical stability of the PF resin relative to the UF resin against degradation b y moisture.3 

### Chapter 2 **Back ground**  In 2007 , the California Air Resources Board (CARB) issued an Airborne Toxic Control Measure (ATCM) 1 to reduce formaldeh yde (HCHO) emissions from hardwood pl yw ood (HWPW) , medium - density

fiberboard (MDF) , and particleboard (PB) . On July 7, 2010 the Formaldeh yd e Standards for Composite Wood Products Act, or Title VIof the Toxic Substances Control Act (TSCA), 15 U.S.C. 2697 was signed into law . 2 The statute establishes HCHO emission standards for HWPW , MDF , and PB sold, supplied, offered for sale, or manufactured in the United States . These emission standards are identical to the CARB ATCM Phase 2 standards. TSCA Title VI also requires EPA to promulgate regulations that include provisions on labeling; chain of custody requirements; sell - through provisions ; finished goods; third - party testing and certification; auditing and reporting of third - party certifiers; recordkeeping; enforcement; laminated products; and exceptions from regulatory requirements for products and components containing de minimis amounts of composite wood products. The statute also specificall y directs EPA to consider provisions for ultra low - emitting formaldehyde (ULEF) resins and no - added formaldeh yde (NAF) resins . TSCA Title VIan d the CARB ATCM both define NAF - based and ULEF - based resins in terms of the composition of the resin sy stem and the maximum HCHO emissions for composite wood products made with these resin sy stems. In general, a NAF composite wood product cannot incorporate a resin formulated with HCHO . A ULEF composite wood product is one made from resins that may

contain HCHO , but that emit it at particularl y low levels. TSCA Title VIand the CARB ATCM define identical statutory maximum emissions for products made with NAF or ULEF resins. The CARB ATCM and TSCA Title VIrequire manufacturers of the regulated composite wood products to demonstrate compliance with the emission standards by emission testing , conducted quarterl y using the ASTM, International (formerly American Society for Testing and Materials (ASTM) ) E1333 large chamber method , 3 or the ASTM D6007 small chamber method4 with a showing of equivalence with ASTM E1333 . Other methods can be used for quality control testing, but these methods must be shown t o be equivalent or to correlate with the ASTM E1333 method . Under the CARB ATCM, manufacturers who use NAF or ULEF resin s may be provided with incentives, such as reduced testing and/or exemption from third - party certification requirements. Recent testing 5 - 7 has indicated that some composite wood products may have increased HCHO emissions when the temperature ( T ) and/or relative humidity ( RH ) are higher than the standard test conditions ( i.e., 25 °C and 50 %RH) required in the ASTM test methods. 3,4 Frihart et al. 5 tested HCHO emissions from small pieces of HWPW panels made with ULEF - UF resin and a soy- based NAF resin at 25 and 35 °C and RH conditions of 30, 75, and 100 % . They reported increases in HCHO emis sion s from the ULEF - UF material at elevated T and RH conditions. In that study HCHO emissions were determined using a modified test method, EN 717 - 3 (Flask Method), which is difficult to compare with ASTM E - 1333 . Parthasarathy et al. 6 tested HCHO4

emissions from four ty

pes of composite wood surface materials taken from temporary housing units and identified as plywood or particleboard . Testing was conducted at 50 and 85 %RH at each of three temperatures (15, 25, and 35 ° C) using chambers of 0.011 m 3 volume . Test results showed that HCHO emissions increased by 1.9 to 3.5 times for a 10 °C rise in temperature, depending on the sample ty pe , and by

1.8 to 2.6 times for a 35 % increase in RH . The data also demonstrated a linear relationship between emissions and RH and and an exponential relationship with temperature. 6 Inresponse to the Frihart et al. study , Riedlinger et al. 7 determined HCHO emissions from four ty pes of PB panels (made with UF, PF, melamine - urea formaldeh yde (MUF) , and poly meric diphenylmethane diisocyanate (pMD I) ) resins . Emissions were determined at multiple time points at both the standard T/RH conditions and at 30 °C/75 %RH using the small chamber test method (ASTM D6007) 4 and the Dy namic Microchamber Method 8 for up to 50 days. A spects of the testing confound comparisons of the data ; f or example , testing at the standard and elevated T/RH conditions was conducted in two different laboratories, using different sampling procedures and anal ytical methods, with sampling at different time points. 7 Nonetheless , the study appears to show that HCHO emissi ons from panels made with all four resin ty pes increased by factors of 2 to 3 under the elevated T/RH conditions. Emissions from panels made with two non - UF resin ty pes (i.e., PF and pMDI) never exceeded the numerical emission limit of 0.09 parts per million (ppm) for PB, even at elevated conditions, whereas emissions from panels made with the UF resins (i.e., UF and MUF) exceed ed that numerical emission limit at elevated T and RH until about 20 or 25 day s after the start of the testing. In addition to the recent studies discussed above , a number of older studies have demonstrat ed that UF resins have increased HCHO emissions under conditions of elevated temperature and humidity . For example, a 1985 review article by Myers 9 analyze d data from numerous studies from 1960 to 1984 on the effects of temperature or humidity on HCHO emissions from UF bonded PB and HWPW . This article conclude d that HCHO emissions increased exponentially with increasing temperature. The relationship between humidity and HCHO emissions was more complex and variable, but the author conclude d that the relationship was approximately linear . These conclusions are consistent w ith the findings noted above from the study by Parthasarthy

et al. 6 Because of the collective evidence that composite wood panels made with UF resins may have increased HCHO emissions under conditions of elevated temperature and humidity, EPA initiated this study

as part of EPA’s effort to consider whether or what ty pe of ULEF provisions to include in regulations implementing TSCA Title VI. The purpose of this study was to as sess the effect of elevated T and RH conditions on HCHO emissions from NAF and ULEF composite wood products made with various resins. This study was designed to use ASTM standard chamber test methods conducted by a CARB - approved TPC laborato ry to determin e HCHO emissions at several T and RH conditions with sufficient repetition to assess the consistency of test results. Subsequent chapters of this report describe the test procedures , data quality , statistical analy sis, and HCHO emission results from the t esting.5 

### Chapter 3 **Test Design and Procedures 3.1 Experimental Design**  Veneer core HWPW panels manufactured using each of three different resin ty pes , NAF - acrylic , ULEF - PF , and ULEF - UF , were tested . The HCHO emissions of each type of HWPW were measured at three different RH conditions ( i.e., 50, 70, and 85 % RH) at each of two different T values ( i.e. 25 °C and 30 °C ). Thus the HCHO emissions were characterized at the standard conditions of 25 °C and 50 %RH required b y the ASTM methods E1333 and D6007, and at higher conditions of T and/or RH. The testing to characterize HCHO emissions was conducted by PFS Corporation (Cottage Grove, WI) , a TPC testing laboratory approved by CARB (http://www.arb.ca.gov/toxics/compwood/listoftpcs.htm) . T esting of the HWPW panels made with three different resin ty pes was carried out in small chambers according to the ASTM D6007 method , as described below . A limited comparison was also conducted of the HCHO emission results from the D6007 small chamber method to those of the E1333 large chamber method. That comparison was conducted with ULEF - UF HWPW panels at two T/RH conditions representing the extremes of the test matrix (i.e., 25 °C/50 %RH and 30 °C/85 %RH). Inall testing , g as - phase HCHO was quantified using the chromotropic acid method as described in the E1333 and D6007 methods . Note that the HCHO emission results reported in this document are as measured at the applicable designated test conditions, i.e., no adjustment to standard conditions (e.g., using the Berge equations cited in the ASTM methods ) 3,4 was made. The results of this study w ere used to (1) determine whether HCHO emissions were statisticall y significantl y affected by elevated T/RH conditions relative to emissions at the standard conditions of 25 °C/50 %RH , (2) determine whether HCHO emissions and any T/RH effects were statisticall y significantly different between HWPW panels of different resin ty pes, and (3) characterize the measurement variability inherent to the small chamber testing. **3.1.1 Large/Small Chamber Test Comparison**  The CARB ATCM and TSCA Title VI emission standards are based on the ASTM E1333 test me thod , and the CARB ATCM requires TPCs to demonstrate on an annual basis that HCHO emission results obtained using the ASTM D6007 method are equivalent to those obtained using the E1333 method. Requirements for that equivalency demonstration include comparison of at least 10 sample sets, with each sample set including nine panel samples tested by the D6007 method in groups of three with the results averaged together, and inclusion of at least fiv e samples sets in each of at least two emission ranges defined b y CARB. 1 The TPC used in this project successfully conducted such an annual equivalency test according to the CARB ATCM **§** 93120 .9 (a)(2)(B) , 1 on July 31, 2012, shortl y before the start of testing for this study . An additional comparison of the large and small chamber methods was conducted in this study , by emission testing of HWPW made with ULEF - UF resin at standard conditions (T = 25°C, RH = 5 0 %) , and at elevated T/RH conditions (T = 30 °C, RH = 85 %). In th is comparison , the6

procedures of the E1333 and D6007 methods were followed, with specific minor exceptions that are noted below and/or described in Section 3.3 . In using both methods , care was taken to maintain low chamber background HCHO concentrations . To accuratel y determine HCHO background concentrations , the TPC laboratory prepared HCHO standards for the chromotropic acid method at lower concentrations than those specified in the ASTM methods , 3,4 and prepared a calibration curve that included those additional calibration points. The ULEF - UF HWPW test material was conditioned for 7 day s before testing in the large chamber as required by the E1333 method ; the conditioning period was 48 hours in the D6007 small chamber testing, considerabl y longer than the minimum of 2 hours required for th at method. This extended conditioning period was chosen to assure that the HWPW was completely equilibrated to the elevated T and RH conditions. For the additional comparison of large (E1333) and small (D6007) chamber methods, a single sample of the ULEF - UF HWPW was tested for HCHO emission in the large chamber at each of the two test conditions noted above. Duplicate air samples were drawn from the large chamber for determination of the HCHO concentration using the chromotropic acid method , and the average of those duplicate sample results was reported as the HCHO emission result. For the small chamber comparison tests, three small specimens (3 in × 7 in) were cut from the interior of each of three separate 4 f ee t × 8 f ee t panels of the ULEF - UF HWPW panels . The nine resulting specimens (three specimens from each of the three panels ) were then conditioned together at the test conditions of T and RH. After conditioning , th e nine specimens were distributed into three identical small test chambers so that each chamber contained one specimen from each of the 4 f ee t × 8 f ee t panels. Thus , each chamber contained identical sets of test specimens. The three small chamber tests were carried out simultaneously . Triplicate air samples were drawn from each of the three small chambers for determination of the HCHO concentration using the chromotropic acid method , and the average of the triplicate sample results from each chamber was reported as the HCHO emission result from that chamber . In both the large and small chamber testing , both the front and back faces of the test pieces were exposed, b ut all edges were sealed with aluminum tape. **3.1.2 Small Chamber Emissions Testing**  S mall chamber (D6007) emissions testing was performed to characterize HCHO emission from each of the three ty

pes of HWPW p anels (i.e., HWPW panels made with three different resins) at each of the six specific T/RH conditions. For each combination of HWPW p anel ty pe and T/RH condition, triplicate tests were conducted simultaneously in three small test chambers. Thus with triplicat e testing of three HWPW p anel ty pes at two T levels and three RH levels, a total of 3 × 3 × 2 × 3 = 54 discrete small chamber tests were conducted , 18 on each of the three HWPW panel ty pes . Cutting of test specimens, sample conditioning , and HCHO sampling for the small chamber tests were performed as described in Section 3.1.1. The test matrix for the small chamber testing is shown in Table 1. For each day of testing, Table 1 shows the HWPW p anel type tested as well as the nominal T and RH test conditions. Table 1 also includes a running number of all the tests (up to 54 total), and indicates the triplicate tests of a single HWPW p anel that were run on a single test day . Table 1 shows the small chamber tests7

**Table 1. Test M**  **atrix and Order of Testing**  **for S**  **mall C**  **hamber T**  **est s**  **. Test**  **Day Test #**  **HWPW**

**Resin Type Temperature**  **Relative Humidity**  **Replicate**

**# Test**  **Day Test #**  **HWPW**

**Resin Type Temperature**  **Relative Humidity**  **Replicate**

**#** 1 1 NAF - acrylic 25 °C 50 % 1 10 28 NAF - acrylic 25 °C 70 % 1 2 NAF - acrylic 25 °C 50 % 2 29 NAF - acrylic 25 °C 70 % 2 3 NAF - acrylic 25 °C 50 % 3 30 NAF - acrylic 25 °C 70 % 3 2 4 ULEF - PF 25 °C 50 % 1 11 31 ULEF - PF 25 °C 85 % 1 5 ULEF - PF 25 °C 50 % 2 32 ULEF - PF 25 °C 85 % 2 6 ULEF - PF 25 °C 50 % 3 33 ULEF - PF 25 °C 85 % 3 3 7 ULEF - PF 30 °C 70 % 1 12 34 ULEF - PF 30 °C 85 % 1 8 ULEF - PF 30 °C 70 % 2 35 ULEF - PF 30 °C 85 % 2 9 ULEF - PF 30 °C 70 % 3 36 ULEF - PF 30 °C 85 % 3 4 10 NAF - acrylic 30 °C 70 % 1 13 37 ULEF -UF 25 °C 50 % 1 11 NAF - acrylic 30 °C 70 % 2 38 ULEF -UF 25 °C 50 % 2 12 NAF - acrylic 30 °C 70 % 3 39 ULEF -UF 25 °C 50 % 3 5 13 ULEF - PF 30 °C 50 % 1 14 40 ULEF -UF 30 °C 70 % 1 14 ULEF - PF 30 °C 50 % 2 41 ULEF -UF 30 °C 70 % 2 15 ULEF - PF 30 °C 50 % 3 42 ULEF -UF 30 °C 70 % 3 6 16 NAF - acrylic 30 °C 50 % 1 15 43 ULEF -UF 30 °C 85 % 1 17 NAF - acrylic 30 °C 50 % 2 44 ULEF -UF 30 °C 85 % 2 18 NAF - acrylic 30 °C 50 % 3 45 ULEF -UF 30 °C 85 % 3 7 19 NAF - acrylic 30 °C 85 % 1 16 46 ULEF -UF 30 °C 50 % 1 20 NAF - acrylic 30 °C 85 % 2 47 ULEF -UF 30 °C 50 % 2 21 NAF - acrylic 30 °C 85 % 3 48 ULEF -UF 30 °C 50 % 3 8 22 NAF - acrylic 25 °C 85 % 1 17 49 ULEF -UF 25 °C 85 % 1 23 NAF - acrylic 25 °C 85 % 2 50 ULEF -UF 25 °C 85 % 2 24 NAF - acrylic 25 °C 85 % 3 51 ULEF -UF 25 °C 85 % 3 9 25 ULEF - PF 25 °C 70 % 1 18 52 ULEF -UF 25 °C 70 % 1 26 ULEF - PF 25 °C 70 % 2 53 ULEF -UF 25 °C 70 % 2 27 ULEF - PF 25 °C 70 % 3 54 ULEF -UF 25 °C 70 % 38

in the chronological order in which they were conducted; due to product availability, testing with the ULEF - UF panels was conducted after testing with the NAF - acryl ic and ULEF - PF panels had been completed. **3.2 Test Materials**  The HWPW panels used for testing were lab e led as NAF or ULEF as per the CARB ATCM and were obtained from major manufacturers who were known to the test laboratory or to EPA as potential sources of such products. Each manufacturer identifi ed the resin ty pe used in their product . All three panel ty pes were 5 - pl y veneer core HWPW; the NAF - acrylic and ULEF - PF panels were 9 millimeters thick , and the ULEF - UF panel s w ere 0.5 inch thick. All materials were obtained as stacks of 4 f

ee t × 8 f ee t panels , sandwiched between additional panels of the same material and wrapped in plastic film. Panels used for testing were taken from the interior of the stack. All panels and cut test pieces were kept wrapped in storage at ambient conditions at the TPC laboratory

until withdrawn for conditioning at test conditions. ULEF - UF panels from two different manufacturers were tested because the first panels tested showed emissions in initial small chamber tests that did not meet the ULEF emission standards. The emission testing results from th o se panels are described in Appendix B. ULEF - UF HWPW panels were obtained from a different manufacturer and were subjected to the full matrix of testing; the results from those ULEF - UF panels are presented in the body of this report. **3.3 Experimental Methods 3.3.1.**  **Large Chamber Tests** With the exception of the elevated T and RH condition used in the comparison to the small chamber test, the large chamber test procedure (ASTM E1333) was used as published, 3 with a product loading ratio of 0.43 meters squared/meters cubed (m 2 /m 3 ) as designated in the method for HWPW panels . The large chamber volume was 22.9 m 3 ( 810 cubic feet ) with an air exchange rate of 0.5/hour. Test specimens remained in the large chamber for at least 16 .5 hours before sampling took place to determine the HCHO concentration. The T and RH in the test chamber were monitored and recorded at 5 - minute intervals throughout the large chamber tests, and those data are summarized in Section 4 of this report. **3.3.2 Small Chamber Tests**  With the exception of the elevated T and RH conditions used in most tests, the small chamber test procedure (ASTM D6007) was used as published, 4 with an area - specific air flow rate (N/L) of 1.17 m eters /h our , as designated for HWPW p anels . This equates to a 0.5/hour air exchange rate with the small chamber volume of 0.19 m 3 ( 6. 7 cubic feet) . The T and RH in the test chamber s were monitored and recorded at 1 - minute or 5 - minute intervals throughout the small chamber tests, and those data are summarized in Section 4 of this report. A c onditioning time of 48 hours w as used to ensure that test specimens were equilibrated to the e levated T and RH condition s used in testing. Weighing of test specimens at 4 - hour intervals throughout9

conditioning before initial tests showed that the 48 - hour duration was sufficient to achieve equilibration with the test conditions. This observation i s consistent with the weighing data of Parthasarath y et al. 6 which showed that most of their ply wood and particleboard samples took about 40 hours to equilibrate. The small chamber tests shown in Table 1 were conducted using three identical small chambers, so that the three tests conducted on each test day were performed simultaneously . Test specimens for small chamber testing were cut from large HWPW panels as described in Section 3.1.1. All nine specimens to be tested on a single day (e.g., the NAF - acrylic specimen s on Test Day 1 in Table 1) were conditioned together in a single conditioning chamber at the planned test conditions of T and RH, and upon completion of conditioning , identical sets of three test specimens were placed into each of the three small test chambers. The HWP W specimens remained in the small test chambers until a steady state HCHO concentration was reached, i.e., until approximately

2.5 hours after the start of the small chamber test . Extensive experience of the TPC laboratory , including real - time monitoring of HCHO using an Interscan 4000 Series continuous HCHO monitor (Interscan Corporation, Simi Valley , CA, USA), showed this 2.5 hour duration to be sufficient to achieve steady state in the small chambers. **3.3.3 Summary of Chamber Parameters** Table 2 summarizes the chamber flow and loading parameters for the large and small chamber tests in this study , including the chamber volume, specimen surface area, loading (i.e., the ratio of specimen surface area to chamber volume), the air exchange rate and air flow rate in the chambers, and the flow rate to surface area ratio. The abbreviations used for these parameters in the ASTM test methods 3,4 are also shown in the table. Table 2 shows that the chamber loading L and flow rate to surface ratio Q/A were the same in the large and small chamber tests. **Table 2. Large and Small Chamber Test Parameters**

**Parameter Units**  **Large C hamber**  **Small Chamber** Chamber volume (V) m 3 22.9 0.19 Specimen surface area (A) m 2 9.85 0.081 Loading (L) m 2 / m 3 0.43 0.43 Air exchange rate (ACH) hr- 1 0.5 0.5 Air flow rate (Q) m 3 /hr 11.5 0.095 Flow rate/surface area ratio (Q/A) m/hr 1.17 1.17 **3.3. 4**  **Chromotropic Acid Analysis** The TPC used the chromotropic acid method to quantify HCHO as specified in the ASTM E1333 and D6007 test methods, but the calibration curve was extended to lower concentrations to assure accurate determination of HCHO emis sion from the panels . Specifically , standards were prepared with smaller amounts of HCHO Standard Solution B than the minimum 0.1 milliliter (mL) volume stated in the E1333 and D6007 methods. 3,4 (Standard Solution B contains 10 micrograms per milliliter [μg/mL ] HCHO, as specified in the ASTM methods.) The calibration results for the chromotropic acid method are summarized in Section 4 .2 of this report.10

In 2010 CARB issued TPC Guideline CWP - 10 - 0 02 10 regarding the limitations of the chromotropic acid method in testing of low - emitting products, and recommended additional efforts (such as linearity

checks) when frequent non - detects occur with the method. Although no non - detects occurred with the me thod in this study , the extension of the calibration curve to low er concentraton s and the confirmation of linearity noted in Section 4.2 are consistent with the intent of CARB CWP - 10 - 002.11 

### Chapter 4 **Quality Assurance/Quality Control** This chapter summarizes the Q uality A ssuran ce/Q uality C ontrol efforts and resulting data quality in this study . The following sections describe the quality of data relevant to the HCHO emission results shown in Section 6 of this report. **4.1 Chamber Test**  **Conditions** The T and RH were controlled in each of the chamber tests to achieve the test conditions shown in Table 1 , with the goal of maintaining chamber T and RH within ± 1 °C and ± 4 %RH , respectivel y, of the nominal conditions as stated in the ASTM E1333 and D6007 methods . 3,4 To this end, the chamber T and RH were measured at 1 - minute or 5 - minute interval s over the entire duration of each chamber test. The mean chamber T and mean chamber RH met the respective ± 1 °C and ± 4 %RH goal s in all the large and small chamber tests . Moreover, during each chamber test, the test conditions were closel y controlled as demonstrated by the fact that the standard deviation of the individual recorded T values was 0.2 °C or less in 39 of the 54 small chamber tests, and never exceeded 0.5 °C . Similarly , the standard deviation of the individual recorded RH values met the ± 4 %RH target in 51 of the 54 small chamber tests, with the only exceptions occurring at elevated RH conditions. Even when controlling at elevated RH conditions, the standard deviation of the individual RH values never exceeded 5.3 %RH. In all cases the actual mean values of T and RH, rather than the nominal values, were used in the statistical analy sis of T and RH effe cts on HCHO emissions. Inspection of the individual T and RH values recorded in each test similarly showed close control of test conditions. All individual T and RH readings were within the target tolerances noted above at all times for the large chamber test conducted at 25 °C/50 %RH, and for all but one five minute reading ( in which the T was just slightly below the target range) for the large chamber test conducted at 30 °C/85 %RH. Of the 3,257 total individual T readings and 3,257 total individual RH readings recorded during the 54 small chamber tests, only 115 of the T readings differed b y more than 1 °C from the nominal test T, and only 251 of the RH readings differed b y more than 4 %RH from the nominal test RH. The individual T or RH readings th at exceed ed the target tolerances occurred primaril y at the most elevated test conditions , or at the beginning of a chamber test when the chamber atmosphere had not yet fully recovered from the perturbation caused by opening the chamber to insert the test specimen s . **4.2 Chromotropic Acid Calibration**  As is standard practice for the TPC, a single chromotropic acid calibration curve relating absorbance to sample HCHO content was prepared at the beginning of this study in August 2012, and was applied to all test data. The calibration curve included a method blank and eight calibration points based on HCHO amounts ranging from 0.019 to 0.372 micrograms ( μg ) in the calibrati on standards . The best fit linear regression calibration curve had the form (micrograms HCHO ) = 17.548 × (absorbance) - 0.0028 μg , with a coefficient of determination (r2 ) of 0.9912. The slope of this calibration curve was within approximately 10 % of previous calibrations12

performed b y the TPC for projects between March and July 2 012, indicating that the response of the laboratory

spectrophotometer and the preparation of the calibration standards we re consistent over time. Fresh sodium bisulfite solution was prepared at least once per week , and the chromotropic acid reagent solution was prepared fresh on each day of testing . The absorbance of the sodium bisulfite + chromotropic acid reagent (or method blank) was measured on each test day as a quality control check. The difference between the absorbance readings of the method bl anks and that of distilled water was alway s less than 0.006 absorbance units ( equivalent to less than 0.014 ppm HCHO in the gas phase) . **4.3 Chamber HCHO Background** Care was taken to maintain low chamber background levels of HCHO during testing, because of the relativel y low emissions exp ected from the HWPW panels being tested . The chamber background HCHO concentration was measured frequentl y using the same chromotropic acid sampling and anal ys is procedures used to determine product HCHO emissions, by sampl ing of the chamber air before test specimens were introduced into the chamber. Chamber background HCHO was not subtracted from the emission test results used in data anal ys is. In the two large chamber tests conducted with the ULEF - UF HWPW for comparison to the corresponding small chamber results (Sections 3.1.1 and 6.1) the large chamber background HCHO was determined to be less than 0.01 0 ppm. In small chamber testing , the mean (± standard deviation) of the small chamber background HCHO values was 0.020 (± 0.0 09 ) ppm, based on 2 2 measurements. A considerable portion of the variability in the small chamber background resulted from two measurements early in the study in which the background exceeded 0.03 ppm. Excluding those two tests , the small chamber HCHO background averaged 0.017 (± 0.005) ppm, based on 20 measurements, with a maximum value of 0.026 ppm and a minimum value of 0.009 ppm . The small chamber average background values meet the ASTM D6007 method4 requirement for background HCHO of not more than 0.02 ppm.13 

### Chapter 5 **Statistical Methods** As noted in Section 3.1, the results of this study w ere used to (1) determine whether HCHO emissions were statistically significantl y different under different T and RH conditions, (2) determine whether HCHO emissions were statistically significantly

different between HWPW made with different resin ty pes, and (3) calculate the measurement variability inherent to the small chamber testing. This chapter summarizes the data anal ys is used to meet these objectives. **5.1 Large/Small Chamber Test Comparison**  Two one - sample comparison tests were performed using HWPW with ULEF - UF resin, one at standard T/RH conditions (T = 25 °C, RH = 50 %) , and one at elevated T/RH conditions (T = 30 °C, RH = 85 %). The data from these tests are reported in Section 6.1 , but due to the small size of the data set no formal statistical analy sis of these data was conducted . **5.2 Small Chamber Emission Tests** A regression model with interactions was used to model the dependence of HCHO emissions from HWPW on T, RH , and resin type. The response variable was HCHO emissions. T emperature and RH we re continuous predictors in the model. Resin ty pe wa s a qualitativ e variable with three classes (NAF - acrylic , ULEF - PF , and ULEF - UF) . The model included an interaction between resin ty pe and T and between resin ty pe and RH. The interaction terms in the model allowed for testing whether the response to T and RH differed by resin ty pe and, if so, whether the effects of T and RH were statistically significant for each resin ty pe. Note that because onl y two T conditions were used in testing, it is not possible to determine from the data whether the dependence of HCHO emission on T is linear or exponential as found by other researchers. 6,9 The regression model assumes linearity with both T and RH, and the results of this study sho u ld not be extrapolated outside the range of the test conditions. Details on the statistical models, hy pothesis tests, and limitations to the statistical methods can be found in the Appendix.14 

### Chapter 6 **Test Results 6.1**  **Large /Small Chamber Comparison**  Table 3 shows the HCHO emission results obtained by testing with the ULEF - UF HWPW in the large (E1333) and small (D6007) chambers. For each of the two test conditions used in this compari s on, Tab le 3 shows the nominal and actual test conditions of T and RH, the individual and mean HCHO results (and standard deviations (SDs)) from the duplicate samples in the large chamber, and the individual and mean HCHO results (and SDs) from the triplicate samples in each of the three small chambers. **Table 3**  **. Results of Large/Small Chamber Comparison with ULEF -**  **UF HWPW Nominal Test**  **Conditions (°C/ %RH)**  **Chamber Actual Test**  **Conditions (°C/ %RH)**  **Individual HCHO**

**Sample Results a**  **(ppm) Mean**  **HCHO**

**Sample Results (ppm)**  **b** 25 / 50 Large 25. 6 / 51. 1 0.051, 0.051 0.051 (± 0.0)

Small c 25. 2 / 49.9

25. 4 / 49. 8 25. 4 / 50. 0 0.049, 0.044, 0.054

0.042, 0.044, 0.052 0.052, 0.044, 0.042 0.049 (±0.005) 0.046 (± 0.005) 0.046 (± 0.005) 30 / 85 Large 29. 3 / 85.1 0.084, 0.092 0.088 (± 0.006)

Small c 30. 2 / 84. 4

30.2 / 84. 7 30. 4 / 84. 4 0.111, 0.123, 0.111

0.108, 0.108, 0.116 0.136, 0.133, 0.133 0.115 (± 0.007) 0.111 (± 0.005) 0.134 (± 0.002) a: Results shown for duplicate samples in large chamber and for triplicate samples in each small chamber. Results are not corrected to standard conditions. b: Average (± standard deviation) c : Results are from three test chambers used simultaneously. Table 3 shows that the large and small chamber test results agreed closel y in testing at the standard conditions of 25 °C and 50 %RH. This observation is consistent with the fact noted in Section 3.1.1 that the TPC laboratory successfully conducted annual CARB equivalency testing shortly before the start of this study . Note that the test results shown in Table 3 have not been adjusted to account for small differences between the actual and standard test conditions. I f the large chamber result of 0.051 ppm obtained at 25. 6 °C and 51. 1 %RH (Table 3 ) were adjusted to standard conditions by

means of the Berge equations cited in the ASTM test methods 3,4 the large chamber result would be 0. 047 ppm. This result is consistent with the CARB approval of the UF HWPW as a ULEF product. Table 3 also shows that the small chamber results at 30 °C and 85 %RH ranged from about 25 to 50 % higher than the large chamber result at those test conditions. The reason for this difference is unclear. However, both the large and small chamber tests at 30 °C and 85 %RH showed HCHO emission s that exceeded those at the standard conditions of 25 °C and 50 %RH.15

**6.2 Small Chamber Emission Tests** Table 4 summarizes the actual test conditions and HCHO emission results from the 54 small chamber tests conducted on the HWPW panels made with different resins . Shown in this table are the resin ty

pe, the average T and RH, and the HCHO emission value in ppm for each small chamber test , and the mean and SD of the three small chamber results in each triplicate set . Table 4 lists the test result s by resin ty pe at each T/RH condition (in the order NAF - acrylic, ULEF - PF, and ULEF - UF) , rather than in the order conducted as in Table 1. The consistency of the triplicate results at each test condition is illustrated by the SD values in Table 4 , which are ≤ 0.006 ppm in most tests, with values of 0.010 to 0.012 ppm in tests with the ULEF - UF panels at el e vated T and/or RH. **Table 4**  **. Test Conditions and HCHO Results from Small Chamber Tests a**  **Resin Type T** 

**(°C) RH**  **(%) HCHO** 

**(ppm) Me**  **an**

**(** ± **SD) Resin Type**  **T (°C)**  **RH (%)**  **HCHO**

**(ppm) Me**  **an**

**(** ± **SD)** NAF - acrylic 25. 4 5 1.4 0.027 0.024 ( ± 0.003) NAF - acrylic 29.8 49.5 0.041 0.036 ( ± 0.00 6 ) NAF - acrylic 25. 7 5 2.8 0.022 NAF - acrylic 30. 1 49. 5 0.038 NAF - acrylic 2 6.0 50. 0 0.023 NAF - acrylic 30. 3 49.9 0.029 ULEF - PF 25.4 5 3.8 0.034 0.037 ( ± 0.003) ULEF - PF 30.2 49.6 0.042 0.046 ( ± 0.003) ULEF - PF 25. 4 5 1.7 0.039 ULEF - PF 30. 2 50. 1 0.048 ULEF - PF 25. 5 5 2.3 0.037 ULEF - PF 30. 3 50.0 0.048 ULEF - UF 25. 2 49.9 0.049 0.047 ( ± 0.00 2 ) ULEF - UF 30. 2 49. 9 0.099 0.095 ( ± 0. 01 0) ULEF - UF 25. 4 49. 8 0.046 ULEF - UF 30. 2 50.0 0.102 ULEF - UF 25. 4 50. 0 0.046 ULEF - UF 30. 3 49.8 0.083 NAF - acrylic 25. 2 70.7 0.019 0.025 ( ± 0.00 6 ) NAF - acrylic 30. 2 69.7 0.034 0.031 ( ± 0.00 4 ) NAF - acrylic 25. 4 69.7 0.026 NAF - acrylic 30. 3 70.1 0.026 NAF - acrylic 25. 5 70.0 0.030 NAF - acrylic 30. 4 69. 2 0.033 ULEF - PF 25.3 70.2 0.023 0.020 ( ± 0.00 4 ) ULEF - PF 30.2 66.5 0.056 0.054 ( ± 0.00 5 ) ULEF - PF 25. 4 70.0 0.016 ULEF - PF 30.2 69.0 0.058 ULEF - PF 25.4 67.7 0.020 ULEF - PF 30. 3 69.8 0.048 ULEF - UF 25.3 70.2 0.067 0.066 ( ± 0.0 11 ) ULEF - UF 30. 2 70.0 0.110 0.108 ( ± 0.00 5 ) ULEF - UF 25. 4 69.8 0.076 ULEF - UF 30. 2 69.6 0.111 ULEF - UF 25. 4 69. 2 0.054 ULEF - UF 30. 4 69.2 0.102 NAF - acrylic 25. 2 84. 9 0.013 0.015 ( ± 0.00 4 ) NAF - acrylic 30.2 8 3.0 0.032 0.032 ( ± 0.0) NAF - acrylic 25. 5 8 5.0 0.019 NAF - acrylic 30. 2 84. 6 0.032 NAF - acrylic 25. 4 84. 9 0.012 NAF - acrylic 30. 4 84.7 0.032 ULEF - PF 25.3 84.9 0.023 0.025 ( ± 0.00 4 ) ULEF - PF 30.2 8 3 .8 0.023 0.025 ( ± 0.00 3 ) ULEF - PF 25. 4 84. 5 0.022 ULEF - PF 30. 3 8 3.7 0.028 ULEF - PF 25. 4 85. 0 0.029 ULEF - PF 30. 3 84. 5 0.024 ULEF - UF 25. 3 84.8 0.081 0.093 ( ± 0.0 12 ) ULEF - UF 30. 2 84. 4 0.115 0.120 ( ± 0.0 12 ) ULEF - UF 25. 5 84. 6 0.104 ULEF - UF 30.2 84. 7 0.111 ULEF - UF 25. 4 85.3 0.095 ULEF - UF 30. 4 84. 4 0.134 a Air exchange rate in all small chamber tests = 0.5/hour Figure 1 display s the HCHO emission results by RH at both 25 °C and 30 °C for all three ty pes of HWPW (i.e., HWPW made with three different resins) in this study . This figure incorporates the test results listed in Table 4 , and illustrates clear trends in the emission results over the range of T and RH used in testing. Figure 1 shows linear relationships with respect to T and RH for the panels made with ULEF - UF (green s ymbols and traces) and NAF - acryl ic (blue s ymbols and traces) resin types. For the ULEF - UF panel , the HCHO emissions at the highest T and RH16

conditions (30 °C/85 %RH) are approximately 0.075 ppm higher than the emissions at the standard conditions (25 °C/50 %RH). A more complex relationship with respect to T and RH is observed for the ULEF - PF panel ty pe (red s ymbols and traces in Figure 1) . For this panel type HCHO emissions are similar for both T levels at 50 %RH and at 85 % RH, but they differ considerabl y at 70 % RH.

TSCA Ti tle VI requires no test result higher than 0.05 ppm (under standard T and RH conditions) for HWPW made with ULEF resins to qualify for a TPC exemption. **Figure 1. HCHO e**  **missions vs.**  **RH for T=25 °C and T=30 °C .**  **6. 2** **.1 Effect of Resin Type on HCHO**  **Emissions** One objective of the study was to determine whether the panels made with the three resin ty pes responded differently

to elevated T and RH. To address this question, we conducted three separate comparisons : ULEF - UF vs. NAF - acryl ic, ULEF - UF vs. U LEF - PF, and NAF - acrylic vs. ULEF - PF. For each pair of resin types, we conducted three h ypothesis tests to determine whether there was a difference in the intercept, a difference in the coefficients corresponding to T, and a difference in the coefficients corresponding to RH. In each hypothesis test, the null

50 55 60 65 70 75 80 85 0.02 0.04 0.06 0.08 0.10 0.12 0.14

RH (%)HCHOEmission(ppm) NA F-acryli c 2 5C

UL EF- PF 25C UL EF- UF 2 5C NA F-acryli c 3 0C

UL EF- PF 30C UL EF- UF 3 0C17

hy pothesis of no difference (e.g., equal intercepts and equal slopes ) was tested against the alternative of a difference (e.g., either the intercept differed or one of the slopes differed). If at lea st one of the h ypothesis tests for a pair of resins found a difference, we concluded that the responses were not identical for that pair of resins. For the ULEF - UF vs. NAF - acryl ic comparison, the intercept, the T coefficient, and the RH coefficient were all statistically different between the two resin ty pes (all three p - values <0.001) , indicating that the two panels used in this experiment behaved differently under the testing condtions . Compared to the NAF - acrylic panels , the ULEF - UF panels emitted a higher level of HCHO overall (higher intercept) and responded differently to changes in T and RH (different slope parameters). This is evident from Figure 1 in that all ULEF - UF results are greater than the corresponding NAF - acrylic results , and the slope of the fitted regression line for the ULEF - UF emission results was higher than that for the NAF - acryl ic emission results . For the ULEF - UF vs. ULEF - PF comparison, the intercept, the T coefficient, and the RH coefficient were all statistically dif ferent between the two resin ty pes (all three p - values <0.001), indicating that the two panels behaved differently under the testing condtions. Compared to the ULEF - PF panels , the ULEF - UF panels emitted a higher level of HCHO overall (higher intercept) and responded differently to changes in T and RH (different slope parameters). This is evident in Figure 1 in that all ULEF - UF panel results are greater than the corresponding ULEF - PF panel results , and the slope of the fitted regression line for the ULEF - UF emission results was higher than that for the ULEF - PF emission results . For the NAF - acrylic vs. ULEF - PF panel comparison, the intercept, the T coefficient, and the RH coefficient were not statistically different between the two resin ty pes (all three p - values > 0.14), indicating that the two panels behaved similarl y under the testing condi tions. This is evident in Figure 1 in that ULEF - PF panel results are mixed among NAF - acrylic panel results and that the fitted regression lines appear similar. The estimated coefficients of the T and RH effect s and the standard errors of those coefficients determined in the statistical anal ys is are summarized in Table 5 , and the results are described in Sections 6.2.2 and 6.2.3 . Table 5 shows, for each panel ty pe, the estimated coefficient s for T and RH, the respective standard error s , and the p - value indicating the strength of the indicated statistical relationship.18 **Table 5**  **. Estimates and Standard Errors from**  **Regression Model Effect**  **Panel Type Estimate**  **d Coefficient**  **Standard**

**Error p**  **- value**  **c** T ULEF -UF 0.00 80 a 0.00078 a < 0.0001 ULEF - PF 0.00 29 a 0.0007 8 a 0.0006 NAF - acrylic 0.0024 a 0.000 80 a 0.00434 RH ULEF -UF 0.0010 b 0.00013 b < 0.0001

ULEF - PF - 0.000 5 b 0.0001 4 b 0.0010 NAF - acrylic - 0.000 2 b 0.0001 4 b 0.1545 a: Units of temperature coefficients and standard errors are ppm HCHO/°C. b: Units of relative humidity coefficients and standard errors are ppm HCHO/%RH. c: Statistically significant effects have a p - value below 0.003 3 , a threshold that ensures an experimentwise error rate of less than α = 0.05. Table 6 summarizes the cumulative effects of T and RH found in this study . For all three panel ty pes, Table 6 shows the statistically determined coefficients that quantify the change in HCHO emission for a unit change in T or RH over the range of conditions teste d. Table 6 also shows the resulting changes in HCHO emission (in ppm) for each resin ty pe that occurred over the range of T and RH used in testing. The changes in HCHO emission due to T and RH are shown separately , and the combined change resulting from both T and RH together is also shown. Table 6 shows that HCHO emission from ULEF - UF and ULEF - PF panel ty pes increased with increasing T over the range of 25 to 30 °C used in testing. However, the effect of T for the ULEF - UF panels was approximately thre e times as large as for the ULEF - PF panels, and amounted to an increase in HCHO emissions of approximately 0.008 ppm per °C increase in T over the indicated range. Table 6 also shows that HCHO emissions from the ULEF - UF panels increased with increasing RH over the range of 50 to 85 %RH used in testing, at a rate of approximately

0.001 ppm per 1 %RH increase over that range. **Table 6**  **. Summary of Temperature and Relative Humidity Effects on Formaldehyde**  **Emissions from**  **Three Types of Hardwood Plywood**  **Resin Type Coefficient of** 

**T or RH Effect Separate Effect on Emissions**  **Combined Effect on**  **Emissions c**  **(ppm HCHO) T**  **(ppm HCHO/°C)**  **RH**

**(ppm HCHO/%RH)**  **T a** 

**(ppm HCHO) RH**  **b**

**(ppm HCHO)** ULEF -UF 0.0080 0.0010 0.0400 0.0359 0.0759 ULEF - PF 0.00 29 - 0.0005 0.0148 - 0.0171 - 0.0023 NAF - acrylic d 0.0024 - 0.0002 0.0121 - 0.0069 0.0052 a : Change in formaldehyde emission (in ppm) due to T between 25 and 30 °C. b : Change in formaldehyde emission (in ppm) due to RH between 50 and 85 %RH. c : Total change in formaldehyde emission due to T and RH between 25 °C/50 %RH and 30 °C/85 %RH. d : Neither T nor RH effects were statistically significant for NAF - acrylic.19

The combined effect of T and RH increased the HCHO emission of the ULEF - UF panels by approximately 0.07 6 ppm between the standard conditions of 25 °C/50 %RH and the most elevated test conditions of 30 °C/85 %RH, with the T and RH effects contributing roughl y equally to this increase. In contrast, the HCHO emissions from the ULEF - PF panels decreased sli ghtly with increasing RH, as indicated by the negative RH coefficient in Table 6 . The combined effect of T and RH on formaldehyd e emission of the ULEF - PF panels was close to zero, i.e., a calculated decrease in emission of approximately 0.00 2 ppm betwee n the standard conditions of 25 °C/50 %RH and the most elevated test conditions of 30 °C/85 %RH. The cause of the apparent reduction in formaldehyde emission with increasing RH for the ULEF - PF panels was not investigated in this study . Riedlinger et al. 7 found that HCHO emission from particleboard made with PF was higher b y approximately a factor of two at 30 °C and 75 %RH relative to emission at standard conditio ns. The reason for the difference in results for ULEF - PF panels in this study

and in Riedlin ger et al. 7 is not known. However, as stated earlier in this report, some of the testing procedures used in Riedlinger et al. 7 confound interpretation of the test results. Inaddition, v ariability in the PF test specimens or in test procedures may be a factor. Uncertainty in measurements due to the very low emission rates of the PF products may also play a role in the variability

of test results. For example, Riedlinger et al. 7 observed a strongl y increasing ratio of elevated to standard condition HCHO emissions over time with the ULEF - PF material, but not with the other three product types tested, and suggested greater measurement error at low ULEF - PF emission rates as a potential cause. Neither the T nor RH effect was statisticall y significant for the NAF - acrylic HWPW panels, and the combined effect of T and RH was close to zero, i.e. a calculated increase in emission of approximately

0.005 ppm between the standard conditions of 25 °C/50 %RH and the most elevated test conditions of 30 °C/85 %RH. **6. 2** **.2 Effect of Temperature on HCHO Emissions**  The effect of T on HCHO emissions f or the ULEF - UF panels used in this study was statisticall y significant (p - value <0.00 0 1) , and the value of the T coefficient was greater than zero ( ≈ 0.008) . This T effect can be seen in Figure 1 in that the 30 °C ULEF - UF emission result s are greater than the corresponding 25 °C ULEF - UF emission result s . Therefore, it was concluded that HCHO emissions from the ULEF - UF panels used in this study increase with T , and that (based on the coefficient in Table 5 ) every 1 °C increase in T between 25 °C and 30 °C results in an increase in HCHO emission of approximately 0.008 ppm. The effect of T on HCHO emissions for the ULEF - PF panel s used in this study was statisticall y signif icant (p - value 0. 0006 ) and the value of the T coefficient was greater than zero ( ≈ 0.003) . Therefore, it was concluded that HCHO emissions from the ULEF - PF panels used in this study increase with T at approximately 0.003 ppm per °C increase in T between 25 °C and 30 °C (based on the coefficient in Table 5 ) . This T effect can be seen in Figure 1 in that most of the 30 °C ULEF - PF emission result s are greater than those of the corresponding 25 °C ULEF - PF samples .20

The effect of T on HCHO emissions for the NAF - acryl ic panels used in this study was not statistically

significant (p - value 0. 00434 ). Although most of the emission result s from the 30 °C NAF - acryl ic panels are greater than the corresponding 25 °C NAF - acrylic emission result s in Figure 1, these T differences are not statistically significant with respect to the panels used in th is study . **6. 2** **.3 Effect of Relative Humidity on HCHO Emissions**  The effect of RH on HCHO emissions for the ULEF - UF panels used in this study was statistically

significant (p - value <0.00 0 1) and the value of the RH coefficient was greater than zero ( ≈ 0.001) . Therefore, it was concluded that HCHO emissions increase with increasing RH for the ULEF - UF panels used in this study at approximately 0.001 ppm for each 1 %RH increase between 50 and 85 %RH. This RH effect is evident in Figure 1 in that HCHO emissions increase as RH increases for the ULEF - UF product . The effect of RH on HCHO emissions for the ULEF - PF panel s used in this study was statistically

significant (p - value = 0. 0010 ) and the value of the RH coefficient was negative ( - 0. 0005 ) . Therefore, it was concluded that HCHO emissions decrease with increasing RH for the ULEF - PF panel s used in this study , at approximately 0. 0005 ppm for each 1 %RH increase between 50 and 85 %RH . A s illustrated in Figure 1, the emission results from the ULEF - PF panel s at 30 °C and 70 % RH are greater than those at both 50 and 85 RH. It is not clear whether those results represent the T/RH behavior of the ULEF - PF material or are due to some variation in the testing . The effect of RH on HCHO emissions for the NAF - acrylic panel s used in this study was not statistically

significant (p - value = 0. 1545 ). **6. 2** **.4 Characterization of Measurement Variability Inherent to Small Chamber Testing**  The variance of the model residuals , calculated using the equation presented in the Appendix , was 6.4958 × 10 - 5

. The square root of this estimator is 0. 00806 ppm , which is slightly lower than the variability

estimate noted in the small chamber ASTM method documentation4 ( i.e., within - laboratory

precision of approximately 0.01 to 0.02 ppm for small chamber tests ) . It is therefore concluded that the within - laboratory variabil ity

in the small chamber tests conducted in this study is well within the variability expected , after accounting for the effects of the variations in T , RH , and resin ty

pe .21 

### Chapter 7 **Summary and Conclusions** Hardwood pl ywood panels made with three different ty pes of ULEF resins were tested to determine the effect on HCHO emissions of T and RH conditions other than the standard test conditions of 25 °C and 50 %RH . The panels tested included HWPW made with NAF - acrylic, ULEF - PF, and ULEF - UF resins. Testing was conducted using the small chamber method (ASTM D6007) under test conditions of 50, 70, and 85 %RH at each of two temperatures (25 and 30 °C). Triplicate small chamber tests were performed on each HWPW - resin panel ty pe at each of the six T/RH conditions. The resulting HCHO emission results were anal yz ed with statistical models to assess the differences in emission behavior from HWPW panels made with the three resin ty

pes, the effects of T and RH on emissions, and the variabili ty of the small chamber test procedure. **Emission Behavior from HWPW**  **P anels made with**  **the Three R esin**  **T ypes**   The study

results show that the ULEF - UF panels differed significantly in emission behavior from both the NAF - acryl ic and ULEF - PF panels.  HCHO emissions from HWPW panels made with ULEF - UF resin were found to increase with T and RH . The effects of both T and RH on emissions from ULEF - UF panels were large in relation to the TSCA Title VI limit of 0.05 ppm and statistically significant with respect to the panels used in the study .  HCHO emissions from HWPW panels made with ULEF - PF resin increased with T but de creas ed with RH . The effects of both T and RH were small relative to the TSCA Title VI0.05 ppm limit, but statistically significant with res pect to the panels used in the study .  The relationship s between HCHO emissions and T and RH for HWPW panels made with NAF - acryl ic resin w ere not statistically significant with respect to the panels used in the study . **Quantified Effects of T and RH on HCHO Emissions**   Statistical analy ses were performed to determine coefficients that quantify the change in HCHO emission s for a unit change in T or RH over the range of conditions tested.  For HWPW panels made with ULEF - UF resin , H C HO emissions increased by approximately

0.0 08 ppm per °C increase in T over the range of 25 to 30 °C , for a fixed RH. HCHO emissions increased b y approximately 0.0 01 ppm for each 1 % RH increase in RH over the range of 50 to 85 %RH , for a fixed T . The combined effect of T and RH was to increase HCHO emissions from the ULEF - UF panels used in this study by approximately

0. 076 ppm between standard test conditions (25 °C/50 %RH) and the most elevated conditions tested (30 °C/85 %RH). The effect of T o n emissions from ULEF - UF panels evaluated for this study was approximately 3 times as great as for ULEF - PF or NAF - acryl ic over the temperature range tested.  For HWPW panels made with ULEF - PF resin , HCHO emissions increased by approximately

0.0 029 ppm per °C increase in T over the range of 25 to 30 °C , for a fixed RH. HCHO emissions decreased by approximately 0.0 005 ppm for each 1 % increase in RH over the range of 50 to 85 % RH , for a fixed T . The combined effect of T and RH was to decrease HCHO emissions from the ULEF - PF panels used in this study by22

approximately

0.00 2 3 ppm between standard test conditions (25 °C/50 %RH) and the most elevated conditions tested (30 °C/85 %RH).  F or HWPW panels made with NAF - acryl ic resin , HCHO emissions increased by about 0 .005 2 ppm between standard test conditions (25 °C/50 %RH) and the most elevated conditions tested (30 °C/85 %RH) , although neither the T nor the RH effect on emissions was statistically

significant with respect to the panels used in the experiment . Table 6 summarizes the results of this study . For each panel type used in the study, Table 6 reports the HCHO emission at the standard testing conditions (25 °C/50 %RH) and at the highest T and RH conditions (30 °C/85 %RH), based on the statistical anal ys is of all test results for that panel ty pe. Table 6 also shows the change in HCHO emissions between the standard testing conditions and the highest conditions. **Table 6. Comparison of HCHO Emissions of Three Hardwood Plywood Panel Types at Lowest and**  **Highest Temperature and Relative Humidity Conditions HWPW**  **Panel Type HCHO**  **Emission**

**at 25 °C/50 %RH (ppm)**  **HCHO Emission**  **at 30 °C/85 %RH (ppm)**  **Change**

**(ppm)** ULEF -UF 0.0471 0.1230 0.0759 ULEF - PF 0.0356 0.0333 - 0.0023 NAF - acrylic 0.0238 0.0290 0.0052 Note: TSCA Title VI requires no test result higher than 0.05 ppm (under standard T and RH conditions) for HWPW made with ULEF resins to qualify for a TPC exemption. The observed emission behavior of the three different ty pes of HWPW used in this study is consistent with the nature of the resins used in their manufacture. The minimal emission rates and absence of T and RH effects with the ULEF -NAF - acryl ic panels reflect the absence of HCHO in the NAF resin. The ULEF - UF and ULEF - PF panels are both made with resins containing HCHO. However, the differences in their emission rates and T and RH effects are consistent with the greater chemical stability of the PF resin relative to the UF resin against degradation b y moisture. This stability makes PF resin wood products particularl y suitable for external applications where exposure to variable environmental conditions may occur. 11 ,1 2 **V ariability of the**  **S**

**mall C**  **hamber Test P** 

**rocedure**  Statistical analy sis of the variability of the small chamber tests produced a variance estimate, the square root of which is 0.00806 ppm.  This uncertainty value is slightly lower than the within - laboratory precision of stated in the ASTM small chamber me thod (approximately 0.01 to 0.02 ppm) . 4  This result indicates that the within - laboratory test variability achieved in this study

is well within the variability expected, after accounting for the effects of the variations in T, RH, and resin type.23 

### Chapter 8 **References** 1. Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products, Section 93120. California Air Resources Board, 2007. Available at http://www.arb.ca.gov/regact/2007/compwood07/fro - final.pdf . 2. Formaldeh yd e Standards for Composite Wood Products Act, 111th Congressional Record S4891 - 92 (daily

ed. June 14, 2010) and H4701 - 05 (daily ed. June 23, 2010), available at http://www.gpoaccess.gov/crecord/digest2010/d14JN101.html . 3. Standard Test Method for Determining Formaldehyde Concentrati ons in Air and Emissions Rates from Wood Products Using a Large Chamber, ASTM E1333 - 96 (2002) , American Society for Testing and Materials, 20 02 . Available for purchase at http://enterprise.astm.org/filtrexx40.cgi?HI STORICAL/E1333 - 96R02.htm 4. Standard Test Method for Determining Formaldehyde Concentrations in Air from Wood Products Using a Small - Scale Chamber, ASTM D6007 - 02 (2008), American Society for Testing and Materials, 2008. Available for purchase at http://dx.doi.org/10.1520/D6007 - 02R08 . 5. Frihart, C. R., Wescott, J. M., Birkeland, M. J., and Gonner, K. M. , Formaldehyde Emissions from ULEF - and NAF - Bonded Commercial Hardwood Pl ywood as In fluenced b y Temperature and Relative Humidity. Published in the Proceedings of the International Convention of the Society of Wood Science and Technology and United Nations Economic Commission for Europe

– Timber Committee. October 11 - 14, 2010, Geneva, Switzerland. 6. Parthasarath y, S., Maddalena, R.L ., Russell, M.L., and Apte, M.G., Effect of Temperature and Humidity on Formaldehdye Emissions in Temporary Housing Units, J. Ai r & Waste Manage. Assoc., 61(6):689 - 695, 2011. 7. Riedlinger, D., Martin, P., and Holloway , T. , Particleboard Formaldehyde Emissions and Decay under Elevated Temperature and Humidity Conditions, study

conducted for Arclin, Inc., March 28, 2012 . 8. Huber, C.W., Anderson, W.H., Vieira, J. W., and Liles, W.T., The Dy namic Microchamber Computer Integrated Formaldehyde Test Sy stem: User Manual, revised version, March 2007 ; available at www.gp - dmc.com . 9. Myers, G.E. , The effects of temperature and humidity on formaldehyde emission from UF - bonded boards: a literature critique , Forest Prod. J. , 35(9):20 - 31 , 1985.24

10. Third Party

Certification Guideline: Li mitations of Chromotropic Acid in Small - Scale Test Methods , Californ ia Air Resources Board Guideline No. CWP - 10 - 002 , June 8, 2010. Available at http://www.arb.ca.gov/toxics/compwood/tpc/cwp_10_002.pdf. 11. The Encyclopedia of Wood, I SB N - 13: 978 - 1 - 60239 - 057 - 7, U.S. Department of Agriculture, Washington, D.C., 1999. 12. Gardziella, A., Pilato, L .A., and Knop, A., Phenolic Resins: Chemistry , Applications, Standardization, Safety , and Ecology , 2 nd Edition, I SB N 3 - 540 - 65517 - 4, Springer Verlag, Berlin, 1999.25 

### Appendix **A Statistical Method**  **ology** This appendix provides det ails on the statistical methodology used to anal yze the data from the small chamber emission tests. **A.1 Overview** A regression model with interactions was used to model the dependence of HCHO emissions from HWPW on T, RH, and resin type. F ormaldehyde emissions , T, and RH are continuous variables in the model. Resin ty pe is a qualitative variable with three classes (NAF - acrylic, ULEF - PF, and ULEF - UF); therefore, two indicator variables were used in the model. The regression model with interactions assumes that after accounting for differences in conditioning and resin type, all measurements are independent of each other. This is a reasonable assumption because all small chamber testing was done on samples from three HWPW panels of each resin ty pe. The experimental units can be viewed as independent samples where the “population” is the exact set of panels used in the experiment (three panels for each of three resin ty

pes). Thus, the experiment satisfies the assumptions underlying the regression m odel. All estimates of variability and tests of statistical significance apply to the variability

due to sampling from the panels in the experiment and using different chambers for testing. These results cannot be extended to the population of panels in current or future use that were not sampled as part of the experiment. We also cannot assess panel - to - panel variability in the panel lots because no single HCHO measurement can be attributed to one specific panel. Before the data were fit to the model, H CHO emissions were plotted against T and RH to determine whether or not a linear relationship was reasonable between the variables. The assumption of a linear relationship between HCHO emissions and T and RH was found to be reasonable for ULEF - UF and NAF - acrylic panels. The relationship between HCHO emissions and T and RH for the ULEF - PF panels was more complex, but a linear relationship was assumed because the source of the complex pattern was not clear , and there were too few experimental conditions to allow consideration of a more complex model . Statistical tests, described below, were conducted to explore the relationships between HCHO emissions and resin ty

pe, T, and RH. The analy sis consists of 15 hy pothesis tests on the various model parameters. Consequently , the threshold significance level was adjusted for each test such that the overall experiment - wise significance level was α = 0.05. The threshold statistical significance level was corrected using the Bonferroni method found in many statistic al texts. A1,A2 To apply this correction, each hy

pothesis was tested at a threshold significance level of 0.0033, which is equal to 0.05/15. This threshold significance value gives an experiment - wise error rate of α = 0.05 adjusted for multiple comparison s. **A.2 Statistical Models** The formulation of the model is as follows. Let26

= HCHO emissions from HWPW from	measurement = T at measurement = RH at measurement = 1 if resin type at measurement is NAF acrylic ; 0 otherwise , and = 1 if resin type at measurement is ULEF PF ; 0 otherwise . The regression model with interactions is then:

= + + + + + + + + + ε (1) Where it is assumed that the ε i terms are independent and identically distributed N ( 0 , σ ) for i = 1 , ... , n . The response function for model (1) is then: [ ] = + + + + + + + + The response function can be simplified according to resin ty pe. For example, the response function for resin ty

pe ULEF - UF, for which Z 1 =0 and Z 2 =0, is as follows: [ ] = + + For resin ty

pe NAF - acrylic , Z 1 =1 and Z 2 =0, and the response function is: [ ] = + + + + + = ( + ) + ( + ) + ( + ) Finally , for resin ty

pe ULEF - PF, Z 1 =0 and Z 2 =1, the response function is: [ ] = + + + + + = ( + ) + ( + ) + ( + ) Thus, interaction regression model (1) implies that each resin ty pe has its own regression line, with different intercepts and slopes for the different resin ty pes. One benefit to using the interaction regression model instead of separatel y fitting thre e regression models, one for each resin type, is that the former model uses 54 observations (see Sect. 3.1.2) as opposed to only 18 observations for each of the three individual models by resin ty pe. Since the interaction regression model has many more ob servations used in its fit compared the other models, it provides a better estimate of the error term ( σ ), and therefore provides more powerful results. Furthermore, a combined regression model facilitates comparing results across resin ty pes, a key ques tion of interest to EPA. **A.3 Hypothesis Tests** In order to investigate whether HCHO emissions were statisticall y significant ly different between HWPW made with different resin ty pes , three formal hy

pothesis tests were performed, one for each pair of resin ty pes.27

Testing the equality

of the two response functions for ULEF - UF and NAF - acryl ic involved the alternatives: : = = = 0 : Testing the equality

of the two response functions for ULEF - UF an d ULEF - PF involved the alternatives: : = = = 0 : If the two tests above both failed to reject the null hy pothesis that the functions were equivalent (i.e., there is no evidence to contradict that = = = 0 and = = = 0 ), then there is no need to test the equality of the two response functions for ULEF - PF and NAF - acryl ic , as that test would also fail to reject the null hypothesis that the response functions are equivalent. If one of the two tests above failed to reject the null hy pothesis and the other test rejected the null hy pothesis (i.e., concluded that the response functions are different), then again there would be no need to test the equality of the two response functions for ULEF - PF and NAF - acryl ic , as that test would also reject the null hy pothesis and conclude that the response functions are not equivalent. If both tests above reject the null hy pothesis and conclude that the response functions are not equivalent, then a third test to test the equality of the two response functions for ULEF - PF and NAF - acryl ic would be conducted using the following alternatives: : = = = : ≠ The results of these tests determine the regression line for each resin, and this in turn impacts the investigation of whether or not formaldeh yde emissions are statistically significantly

different under different T or RH conditions. For example, if all three tests above fail to reject the null hy pothesis, then this essentially means that there is not enough evidence to conclude a different regression line for each resin. In other words, model (1) reduces to

= + + + ε For this reduced model, testing whether or not HCHO emissions are statistically significantly different under different T conditions for any resin type involves the alternatives: : = 0 : ≠ 0 Similarly for the reduced model, testing whether or not HCHO emissions are statistically significantl y different under different RH conditions for any resin ty pe involves the alternatives: : = 028 : ≠ 0 However, if at least one of three response function equivalency tests between two resins rejects the null hy

pothesis, then model (1) may be reduced, but not to the extent just shown. For example, if all three response function equivalency tests reject the null hy

pothes is, meaning that each resin ty

pe has a unique regression line, then as previousl y shown , the response function for resin ty pe ULEF - UF (Z 1 =0 and Z 2 =0) is: [ ] = + + For resin ty

pe NAF - acrylic (Z 1 =1 and Z 2 =0) the response function is: [ ] = ( + ) + ( + ) + ( + ) And for resin ty

pe ULEF - PF (Z 1 =0 and Z 2 =1) the response function is: [ ] = ( + ) + ( + ) + ( + ) Thus, model (1) implies that each resin type has its own regression line, with different intercepts and slo pes for the different resin ty pes, so different hy

pothesis tests were conducted to determine the statistical significance of T and RH for each resin ty pe. Under this “full” model, testing whether or not HCHO emissions are statistically significantl y different under different T conditions for ULEF - UF involves the alternatives: : = 0 : ≠ 0 Similarly under this “full” model, testing whether or not HCHO emissions are statisticall y significantl y different under di fferent RH conditions for ULEF - UF involves the alternatives: : = 0 : ≠ 0 Again under this “full” model, testing whether or not HCHO emissions are statistically significantl y different under different T conditions for NAF - acrylic involves the alternatives: : + = 0 : + ≠ 0 and testing whether or not HCHO emissions are statistically significantl y different under different RH conditions for NAF - acrylic involves the alternatives: : + = 0 : + ≠ 029

Fin ally under the “full” model, testing whether or not HCHO emissions are statistically significantl y different under different T conditions for ULEF - PF involves the alternatives: : + = 0 : + ≠ 0 and testing whether or not HCHO emissions are statistically significantl y different under different RH conditions for ULEF - PF involves the alternatives: : + = 0 : + ≠ 0 The tests of whether or not HCHO emissions are statistically significantl y different under different T and RH conditions have been outlined for the cases where model (1) reduces completely

to one regression line and where model (1) is not reduced at all (i.e., the “full” model). However, depending on the data and the outcomes of the equivalency response function test s between two resin types, model (1) ended up being something between these two extremes, and statistical tests involving T and RH were modified accordingly. That is, the anal ys is found that ULEF - UF behaved differentl y from ULEF - PF and NAF - acrylic, but ULEF - PF and NAF acryl ic behaved similarl y to each other. Based on their similarities, statistical tests could be modified to examine the effect of T/RH on the combined ULEF - PF/NAF - acryl ic observations. However, because of the chemical and phys ical differ ences between ULEF - PF and NAF - acryl ic, all statistical tests were conducted assuming 3 separate resin ty pes. **A.4 Characterizing Measurement Variability** T o characterize the measurement variability inherent to small chamber testing, the following estimator was calculated:

= 1 45 ( − ) where is observation i and is the predicted value for observation i on the appropriate fitted regression line . is an unbiased estimator for σ , the variance of model (1). The square root of this estimator (S

) was compared to the within - laboratory precision estimate noted in the ASTM D6007 documentation4 of approximately 0.01 to 0.02 ppm . **References for Appendix A** A1. Dean, A. and Voss, D. (1999) Design and Analy sis of Experiments. New York: Sp ringer. A2. Hsu, J. C. (1996) Multiple Comparisons: Theory and Methods. Boca Raton: Chapman & Hall/CRC.30 

### Appendix B **Emission Testing of First Batch of Commercial**  **ULEF -**  **UF Panels B.1**  **Introduction** The first batch of ULEF - UF panels tested gave unexpectedly high emission testing results and therefore were not used in evaluating the effects of temperature and humidity on emissions. This appendix describes these panels and the emission testing results. **B. 2**  **Product Description** The first ULEF - UF panels tested were 5 - pl y veneer core HWPW, 0.5 inch thick and 4 ft b y 8 ft in size. The panels were manufactured on July 10, 2012, and shipped directly from the manufacturer to the testing laboratory , where they were received on July

16 as a stack of 10 p anels wrapped in plastic sheet. The panels were labeled as compliant with the CARB ATCM and “93120 TPC Exempt.” The panels were stored, cut to size for chamber testing, and equilibrated with T and RH conditions as described in section 3.1.1 of this study report. **B.3 Emission Testing**  The HWPW was subjected to HCHO emission tests using both the ASTM large chamber (E1333) and small chamber (D6007) methods. The tests were intended to provide a comparison of the HCHO emissions when determined under the same T and RH conditions by both the large and small chamber methods. Table 1 summarizes the 13 tests conducted on the HWPW panels . The tests in Table 1 are listed and numbered in chronological order, and the table shows the test date, the chamber size (larg e or small), the nominal and actual T and RH conditions, the HCHO emission in ppm, and notes concerning each test. As described in section 3.1.1, the large chamber tests were conducted singl y, whereas the small chamber tests were conducted as simultaneous triplicate tests.31

**Table B.**  **1. Chamber tests conducted on a Commercial**  **Veneer Core Hardwood Plywood Test**  **Number Date**  **Chamber Nominal**  **T/RH (°C/%)**  **Actual T**

**/RH (°C/%)**  **HCHO**

**Emission (ppm)**  **Notes** 1 8/2/12 Large 1 25/50 25.6/49.1 0.080 Invalidated – 48 hour conditioning 2 8/2/12 Sm all 2 25/50 25.3/50.0 0.117 3 8/2/12 Sm all 25/50 25.1/50.0 0.110 4 8/2/12 Sm all 25/50 25.5/50.2 0.110 5 8/8/12 Large 30/85 30.0/85.1 0.220 Invalidated – 48 hour conditioning 6 8/14/12 Sm all 25/50 25.5/51.0 0.123 7 8/14/12 Sm all 25/50 25.1/50.1 0.120 8 8/14/12 Sm all 25/50 25.4/50.9 0.120 9 8/17/12 Sm all 30/85 30.0/90.2 0.166 10 8/17/12 Sm all 30/85 30.1/86.9 0.162 11 8/17/12 Sm all 30/85 30.6/92.2 0.155 12 8/24/12 Large 25/50 26.1/50.5 0.040 Repeat of Test 1 – 7 day conditioning 13 9/26/12 Large 30/85 30.1/85.1 0.199 Repeat of Test 5 – 7 day conditioning 1 : ASTM E1333 2 : ASTM D6007 As a comparison of large and small chamber results at the same T and RH conditions, it was intended that Test 1 would be compared to Tests 2 to 4, and that Test 5 would be compared to Tests 9 to 11. Tests 6 to 8 were small chamber tests conducted as part of the planned T/RH test matrix, and are replicates of Tests 2 to 4. However, the HWPW panel s were only conditioned for 48 hours prio r to Tests 1 and 5, rather than for 7 day s as required in the large chamber method, and consequently , those two tests were invalidated and were repeated as Tests 12 and 13, respectivel y. Table 1 shows that after 7 day s of conditioning at the standard T an d RH conditions of 25 °C and 50 %RH (Test 12), the HWPW exhibited a HCHO emission of 0.040 ppm in the large chamber test, consistent with its designation as a ULEF product (the ULEF emission standard is 0.05 ppm). However, in the corresponding small chamb er tests (Tests 2 to 4 and 6 to 8) the HWPW exhibited HCHO emissions ranging from 0.110 to 0.123 ppm, substantially higher than both the large chamber result and the ULEF emission standard. Samples for the small chamber tests were conditioned for 48 hours at the test conditions prior to testing. Table 1 also shows that after 7 day s of conditioning at the elevated T and RH conditions of 30 °C and 85 %RH (Test 13), the HWPW exhibited a HCHO emission of 0.199 ppm in the large chamber test. In the corresponding small chamber tests (Tests 9 to 11) the HWPW exhibited HCHO emissions ranging from 0.155 to 0.166 ppm. These results suggested that the HCHO32

emissions of the ULEF - UF HWPW increased at the elevated T and RH conditions relative to those at the standard T and RH conditions. Because of the unexpectedly high HCHO emissions of the HWPW in the small chamber tests at standard conditions (Tests 2 to 4 and 6 to 8) , testing of this batch of panels was discontinued, and panels from another manufacturer were obt ained . The intent of this study was to assess the impact of elevated T and RH on HCHO emissions of panels that meet the NAF or ULEF definitions . Because the se HWPW panels did not meet the ULEF emission standard in the small chamber tests at the standard conditions, they were not used for evaluating the impact of elevated T and RH on formaldeh yde emissions.