External Peer Review of EPA’s Draft Document

Peer Reviewers:

Randy L. Maddalena, Ph.D.

Bettina Meyer 

Octavia Zeleniuc, Ph.D.

Contract No. EP-C-12-045

Task Order 18

Final Peer Review Report

Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of 

Temperature and Relative Humidity

September 6, 2013

Prepared for:

U.S. Environmental Protection Agency

Office of Pollution Prevention and Toxics

1200 Pennsylvania Ave., NW (7404T)

Washington, DC 20460

Prepared by:

Versar, Inc.

6850 Versar Center

Springfield, VA 22151
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Contents

I. INTRODUCTION..................................................................................................................... 1

II. CHARGE TO REVIEWERS.................................................................................................. 2

III. INDIVIDUAL PEER REVIEWER COMMENTS ............................................................. 3

Randy L. Maddalena, Ph.D......................................................................................................... 4

Bettina Meyer.............................................................................................................................. 8

Octavia Zeleniuc, Ph.D............................................................................................................. 15
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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I. INTRODUCTION

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 

formaldehyde emission standards for hardwood plywood (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 (ATCM). Both 

TSCA Title VI and the CARB’s ATCM require formaldehyde emission testing to be conducted 

quarterly using the ASTM, International (formerly American Society for Testing and Materials 

(ASTM)) E1333 large chamber method or ASTM D6007 small chamber method. 

Recent testing has suggested that some ultra-low emitting formaldehyde (ULEF) composite 

wood products may have significantly increased formaldehyde 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-acrylic, ULEF-PF (phenol-formaldehyde), and ULEF-UF 

(urea-formaldehyde) resins were determined using standard methods by a CARB-approved TPC 

laboratory at several T and RH conditions. In addition to testing at the standard T/RH conditions, 

each HWPW type (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 type 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 purpose of the requested letter review is for EPA to receive written comments from 

individual experts, who were selected by Versar having expertise in testing formaldehyde 

emissions from composite wood products. Final written comments received from reviewers will 

be made publically available on EPA’s electronic public docket and online comment system 

(Regulations.gov).

Peer Reviewers:

Randy L. Maddalena, Ph.D.

Lawrence Berkeley National Laboratory

Bettina Meyer 

Fraunhofer Institute for Wood Research 

Wilhelm-Klauditz-Institut (WKI) 

Octavia Zeleniuc, Ph.D.

Transilvania University of Brasov
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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II. CHARGE TO REVIEWERS

Charge Questions: 

1) Is the study scientifically sound? Was it designed and conducted properly?

2) Are the results presented clearly and appropriately?
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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III. INDIVIDUAL PEER REVIEWER COMMENTS
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Review by:

Randy L. Maddalena, Ph.D.
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Peer Review Comments on EPA’s Draft Report Measuring Formaldehyde Emissions from 

Low Emitting Hardwood Plywood Panels under Different Conditions of Temperature and 

Relative Humidity

Randy L. Maddalena, Ph.D.

Lawrence Berkeley National Laboratory

August 5, 2013

I. GENERAL IMPRESSIONS

New federal and state laws have moved the building industry toward the use of materials that 

emit less pollutant indoors with particular emphasis on lowering formaldehyde exposures. As a 

result, the use of ultra-low emitting formaldehyde (ULEF) resin and no added formaldehyde 

(NAF) resin in composite wood products is increasing. The EPA is required to develop new 

regulations to implement the new standards for lower formaldehyde emissions and to consider 

provisions for materials made with ULEF and NAF resins. Test methods are available for 

measuring the amount of formaldehyde emitted from composite wood products under 

standardized test conditions but the methods do not consider the effect of environmental factors 

such as temperature (T) and/or (RH) relative humidity. Several published studies of composite 

wood products have shown a significant and positive correlation between formaldehyde emission 

and both temperature and relative humidity. 

The subject of this review is an investigation of the effect of temperature and humidity on 

formaldehyde emissions from composite wood products made with ULEF and NAF resins. The 

work was done to support EPA’s efforts in developing new regulations and provisions 

implementing new formaldehyde emission standards. I commend the EPA for recognizing the 

potential importance of T/RH and initiating this study. The stated goals of the project are to 

determine whether formaldehyde emissions are affected by elevated T/RH conditions relative to 

the standard conditions; to determine whether different resin types respond to T/RH differently;

and to characterize the variability of results from emission tests using small chambers.

Overall, the project was well conceived and work appears to be careful and complete producing 

high quality data. The report is very well written and the conclusions are reasonable and 

generally supported by the work. 

II. RESPONSE TO CHARGE QUESTIONS 

1. Is the study scientifically sound? Was it designed and conducted properly?

The objectives and methods of the study were clearly articulated and the experimental design 

was appropriate to address the stated objectives. The quality of the work is excellent, including 

sufficient quality assurance measures and data interpretation. I particularly like the detail given 

to measuring and reporting the variability in the small chamber test method results and the 

careful comparison between the small and large chamber methods. 
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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I have two issues with the experimental design described below. First, the study used only two 

temperature levels. Using only two temperature levels limits the ability to characterize the 

linearity of the emission/temperature profile. This limitation is not expected to weaken the results 

of the study because the work was focused specifically on the issue of increasing temperature 

and humidity above the standard conditions and only tested a relatively small temperature range 

(25 C - 30 C). Given how the hypotheses were formulated and the limited temperature range 

being tested, the assumption of linearity in the emission/temperature profile is probably valid. 

However, the authors should clarify that previous studies found that the relationship was not 

linear and discuss how those findings might impact their conclusions. For example, both Myers 

(1985, cited in the report) and Parthasarathy et al. (2011 citation provided at end of the review) 

found an exponential relationship between formaldehyde emissions and temperature, so it is 

probably not advisable to extrapolate the relationship found in this study beyond the range tested.

The second issue may be more significant. This reviewer is not familiar with the chromotropic 

acid method used in the study but NIOSH 3500 method states that there may be negative 

interference in the formaldehyde measurement if phenols are present at levels greater than 8:1 

relative to formaldehyde. This interference may have already been resolved in the method used 

by the third party certifier. However, the report stated that the PF product tested in Riedlinger et 

al. (2012) seemed to show an increase in emission with T/RH (page 4, paragraph 1 in the report), 

which is inconsistent with the findings of the current report. The authors need to discuss why 

their results differ from Riedlinger et al (2012) and discuss the possibility that the lower apparent 

emissions from the ULEF-PF HWPW samples may be due to interference in the analytical 

method. If the reason for the lower formaldehyde concentrations is an artifact of the analytical 

method, where experimental conditions resulted in higher concentration of phenols in the test 

chamber, then the comparisons with ULEF-PF may not be valid. 

2. Are the results presented clearly and appropriately?

The results of this report are very clearly presented in sufficient detail to support conclusions 

with a few exceptions mentioned above and in the specific observation. 

III. SPECIFIC OBSERVATIONS

Page Line Comment or Question

1 - 2 The Executive Summary is very well written and complete. 

4 2 The Myers (1985) citation in the background found that 

formaldehyde “emissions increased exponentially” with increasing 

temperature. This point should be reconciled with the authors’ 

assumption of a linear relationship between emission and 

temperature later in the report. Again, I don’t expect this to change 

the results of the statistical analysis but should be discussed in the 

report.

6 1 I agree with the authors’ use of an extended conditioning time at the 

higher T/RH conditions. Others have found that for some composite 

wood materials, it may take from one to ten days for the material to 

come to equilibrium with the humidity (Parthasarathy et al. 2011). It 
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

is unclear what effect the continued uptake of moisture into the 

material will have on emission rates but future work may want to 

confirm that moisture uptake into composite wood does not increase 

formaldehyde emissions. 

6 2 The exposed surface area of the HWPW is reported here but it is not 

clear whether the edges/backs are covered. When I tried to estimate 

the area and other test conditions from the information provided in 

the report (page 6, paragraph 2 and page 8, section 3.3.1 and 3.3.2) I 

was not able to reconcile the factors in the small and large chambers. 

I suggest providing a table with the following factors listed for both 

the large and small chambers: Loading (L, m2/m3); Air change rate 

(ACH, 1/h); Chamber volume (V, m3); Ventilation rate (Q, m3/h); 

Area of emitting surface including edges (A, m2). 

One of the most important factors that influence results from 

different size chambers when the emissions are reported at 

concentration (ppm) is the Q/A (m/h). I was not able to confirm that 

Q/A was the same for both chambers. I was also not able to confirm 

the emitting sample area for the small and large chambers.

11 2 Paragraph 2 and Section 4.3 report the method blanks (~0.006) and 

chamber blanks (range from 0.009 to more than 0.03, average 0.017 

ppm after excluding outlier). Were the blanks/background 

concentrations subtracted from the measurements when the data were 

processed? 

11 4 Was a formal statistical test used to identify and exclude the two 

outliers that “exceeded 0.03 ppm”?
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Review by:

Bettina Meyer
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Peer Review Comments on EPA’s Draft Report Measuring Formaldehyde Emissions from 

Low Emitting Hardwood Plywood Panels under Different Conditions of Temperature and 

Relative Humidity

Bettina Meyer 

Fraunhofer Institute for Wood Research 

Wilhelm-Klauditz-Institut (WKI)

July 30, 2013

I. GENERAL IMPRESSIONS

This technical report presents an interesting piece of work. The formaldehyde emission from 

wood based panels has been investigated and published by several authors. In 1974, a very

important study on the impact of temperature and relative humidity, resulting in a mathematical 

model, was published by I. Andersen, Gunnar R. Lundquist und Lars Molhave, “Liberation of 

formaldehyde from particleboard. A mathematical model” (Ugeskr. Læg. 1974: 136: 2145-

2150). 

The topic became more and more important due to the discussion of decreasing/reduction of 

formaldehyde limit values for wood based panel products worldwide considering the 

classification of formaldehyde as a toxicologically relevant compound. In addition, the impact of 

temperature and relative humidity became relevant because of different reference chamber test 

standards worldwide. 

From my point of view, this technical report can only be regarded as an indication showing the 

impact of temperature and relative humidity on low emitting plywood boards and not as a 

scientific report showing important new aspects / assessment parameters or a generally valid 

calculation formula due to the several remarks mentioned in this review.

II. RESPONSE TO CHARGE QUESTIONS 

1. Is the study scientifically sound? Was it designed and conducted properly?

The technical report is well written and the topic is very important. A detailed description and 

interpretation of test results was given on basis of the obtained test results. 

But due to the following items below, the experimental approach and the results and their 

interpretation/statistical evaluation need a major revision.

 Special production process of test material caused by the multi-layer structure. Note: only 

5-layer glued boards with a thickness of 9 mm (and 0.5 inch – mistake?) have been tested, 

other thicknesses having more or fewer layers may cause different results and need to be 

verified;

 High chamber blank values (in relation to very low emitting test materials); and

 Analytical procedure used (chromotropic acid method)
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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From my point of view, this technical report in the present form can only be regarded as an 

indication showing the impact of temperature and relative humidity on low emitting plywood 

boards. 

The statistical evaluation of the results is complex, but cannot be assessed on the basis of the 

available data with respect to these test results due to reasons mentioned above. Details are 

discussed in following pages of this review.

2. Are the results presented clearly and appropriately?

The background, experimental work, and statistical evaluation of test results are described 

accurately and understandable – with some small exceptions as stated below. The technical 

report was written in a very structured and understandable way. The literature is adequately 

cited, but has to be extended. There are some important publications missing. 

My recommendation: In the present form, the article cannot be published and needs a major 

revision.

III. SPECIFIC OBSERVATIONS

In the following, I will mainly comment on the main parts or chapters and refer to corresponding 

pages.

Page Line Comment or Question

1-2 Chapter 1: 

Executive 

Summary

The summary gives a good overview of the topic and the main results of 

this work. 

3-4 Chapter 2:

Backgrou

nd

Excellent description of the current situation, beginning in 2007 with the 

CARB regulation and some first test results concerning the variation of 

temperature and relative humidity as the base to continue studies on this 

topic. 

5-9 Chapter 3:

Test 

design and 

Procedure

s

This chapter gives a good overview of the experimental design of the 

investigation. The samples, test methods, and analytical procedure are 

described in detail, but raise some questions: 

Page 8

3.2 Test material

Test material “All three test materials were 5-ply veneer core HWPW: 

NAF-acrylic and ULEF-PF panels were 9 millimeters thick, the ULEFUF panels were 0.5 inch thick.” Is this a mistake: 5-layer plywood with 

thickness of 0.5 inch?

3.3.2 Small chamber tests

“A conditioning of 48 hours was used to ensure that test materials were 

equilibrated to the elevated T and RH conditions used in testing.”

“The HWPW specimens remained in the small chambers until steady 

state HCHO concentration was reached, i.e., approximately 2.5 hours 

after the start of the small chamber test.” Does it mean that the test 
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

samples were conditioned only for 48 hours and testing was done for 2.5 

hours? A clarification should be given in the description. 

Referring to ASTM D 6007, the test has to be carried out until a steady

state concentration is reached and the time has to be calculated by an 

equation using the mass transfer coefficient or a second possibility is to 

run the small chamber with preconditioned samples as the large ASTM 

E 1333 chamber test (7 days). 

If the samples were only conditioned for 48 hours, are there some 

additional test results to verify the proper conditioning of the samples –

meaning was the equilibrium reached? Are the K-values calculated 

and/or are there additional test results to verify a steady state 

concentration? 

Page 9:

3.3.3 Chromotropic acid analysis 

The calibration curve was extended to lower concentrations to “assure 

accurate determination of HCHO emissions from the panels”... 

(summary in Section 4 of the report). From my point of view, the 

chromotropic acid method can no longer be regarded as the “state of the 

art” analytical test method for formaldehyde determination due to 

several problems – see below. Another analytical method has to be used 

to determined formaldehyde emission – especially for these low 

ranges/levels.

As stated in:

- ASTM E 1333 standard, “Detailed procedures based on acetyl acetone, 

pararosanilin, DNPH and MBTH have been found to give results 

equivalent or greater in accuracy and precision than chromotropic acid”

and

- ASTM D 6007 standard, “NIOSH 3500 analytical method: phenols as 

negative interference at an 8:1 excess over formaldehyde, modifications 

in the analytical procedure shall be made when relatively high phenol to 

formaldehyde concentration (8:1) are anticipated (Lit.: Hakes, D., 

Johnson, G. and Marhevka, J., April 1984 and Technical Bulletin No. 

415, 1983).”

Additionally, the CARB ATCM Standard Operating Procedure (SOP) 

SAS 20, “Sampling and Analysis of Formaldehyde Emissions from 

Composite Wood Products,” June 2012, describes the DNPH method by

analysis by high performance liquid chromatography (HPLC) as 

analytical procedure with detection limits of 0.6 ppb and estimated 

quantification limit (EQL) of 3 ppb.

In 2010, difficulties in high detection limit have already been noticed by 

CARB in reference to small-scale test methods in combination with 
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

NIOSH 3500 chromotropic acid method and were published in CWP10-002. Therefore, CARB recommends using MBTH or the acetyl 

acetone method for small-scale test methods. 

10-11 Chapter 4: 

Quality

Assurance

/ Quality

Control

Page 10

4.1 Chamber Test Conditions

The test conditions are described well, but background test results in the 

conditioning chamber are an important parameter in addition. 

Investigations of very low emitting materials stored in an area of high 

emitting materials can showed an impact on absorbing formaldehyde. 

4.2 Chromotropic Acid Calibration

Only a single calibration curve has been established at the beginning of 

this study in August 2012 and the slope was compared to the calibration 

curves done between March and July 2012 in this laboratory. It was 

indicated based on the slope, that the laboratory spectrophotometer and 

the preparation of calibration standards were consistent over time. 

As mentioned in this chapter, this is a standard practice for the TPC, but 

from my point of view it is not sufficient. 

The ISO, JIS, and EN standards request a calibration curve in a 

continuously repeating period. For example, the European reference 

chamber test method for wood-based materials EN 717-1, 2005-01: 

“Wood-based panels – Determination of formaldehyde release, Part 1: 

Formaldehyde emission by the chamber method” requires in chapter 

9.4.1 “The calibration curve shall be checked at least once a week.” 

European labs being accredited have to act this way and WKI uses the 

same procedure for ASTM chamber test evaluation, as well as for 

European test methods.

Page 11

4.3 Chamber HCHO Background

The large chamber background was detected with 0.010 ppm, small 

chamber backgrounds were given with an average value of 0.020 (+

0.009) ppm for 22 measurements, excluding two tests which exceeded

0.03 ppm, the averaged background level was given with 0.017 (+

0.005) ppm, with a maximum of 

0.026 ppm and a minimum of 0.009 ppm.

Indeed, the background levels determined during this investigation 

correspond to those requested by ASTM standards. 

From my point of view, the background level has to be much lower to 

determine the formaldehyde emission of very low emitting materials. 

Referring to the European test chamber standard EN 717-1, the 

background level has to be lower than 0.005 ppm before starting the 
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Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

test.

12 and 

Annex

Chapter 5: 

Statistical 

Methods 

(and 

Appendix)

It can be regarded as complex statistical work, but I assume that the 

results cannot be assessed accurately based on the basis of the 

obtained/available data.

13-19 Chapter 6: 

Test 

Results

Page 14

6.2 Small Chamber Emission Tests 

In Table 2, the test results were mentioned in order of testing (ref. Table 

1) but this causes a difficult overview of test results in respect to the 

impact of T and RH. 

My proposal is to sort the test results corresponding to the test material 

first. The second criteria can be the temperature and third criteria the 

relative humidity.

Example:

Resin 

type

T RH HCHO mea

n

Resin 

type

T R

H

HCHO mean

NAFacrylic25 50 ... ... NAFacrylic30 50 ... ...

25 70 ... ... 30 70 ... ...

25 85 30 85

ULEF-PF 25 50 ULEFPF30 50

25 70 30 70

25 85 30 85

ULEFUF25 50 ULEFUF30 50

25 70 30 70

25 85 30 85

As shown in Table 2, the lowest test result has been detected with 0.012

ppm for NAF-acrylic boards (average of 0.015 ppm). Most of the test 

results are within the range of 0.02 up to 0.05 ppm, and only the results 

for ULEF-UF boards exceed this range after increasing the temperature 

and/or relative humidity. 

Due to high background level (blank value) of chambers and the 

analytical method chromotropic acid, the test results have to be regarded 

critical. Measuring an average blank value of the test chamber of app. 

0.02 ppm (see technical report, page 11), a test result of 0.012 ppm has 

to be verified because the blank value was lower than those measured 

for the test sample.

Page 15

“A more complex relationship with respect to T and RH is observed for 
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Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

the ULEF-PF panel type. For this panel Type HCHO emissions are 

similar for both T levels at 50% RH and at 85%RH, but they differ 

considerably at 70%RH. It is not clear what is causing this type of 

relationship.” 

As stated above, the analytical method used (chromotropic acid) can 

probably cause minor values and misinterpretation because phenols are 

regarded as causing a negative interference at an 8:1 excess over 

formaldehyde. For verification, another analytical test method (acetyl

acetone or DNPH) had to be used. An inhomogeneity of test material 

may also be considered. 
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Review by:

Octavia Zeleniuc, Ph.D.
External Peer Review of EPA’s Draft Document: Measuring Formaldehyde Emissions from Low Emitting 

Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Peer Review Comments on EPA’s Draft Report Measuring Formaldehyde Emissions from 

Low Emitting Hardwood Plywood Panels under Different Conditions of Temperature and 

Relative Humidity

Octavia Zeleniuc, Ph.D.

Transilvania University of Brasov

July 29 2013

I. GENERAL IMPRESSIONS

Overall it is a comprehensive report, developed on 8 chapters (references included) well defined, 

presenting relevant data related to the effect of elevated T and RH conditions on formaldehyde 

emissions from hardwood plywood with veneer core made with various resins. 

The motivation for this study was described in Chapters 1 and 2, where a few references are 

mentioned highlighting the influence of temperature and relative humidity on formaldehyde 

emissions from wood composite panels. 

It is a clear presentation, logically organized, including sufficient data presented in appropriate 

tables and graph, which sustain the results, interpretation, and conclusions. 

In general, explanations are included that clarify the presentation and avoid confusion in 

interpretation of results (e.g., establishing the test matrix, presentation in details of statistical 

methodology used in data analysis, equivalency tests for large/small chamber comparison, 

experiments on the first batch of ULEF-UF panels). 

The objectives of the study were achieved and the conclusions are technically sound, supported 

by all the technical data and statistical interpretation.

II. RESPONSE TO CHARGE QUESTIONS 

1. Is the study scientifically sound? Was it designed and conducted properly?

The study is technically sound and includes evidence for any statements or conclusions that it 

makes.

The report contains accurate information on procedures, facilities, quality assurance and control, 

and results:

Procedure and facilities:

 Tests are performed according to standard methods recommended for this type of product, 

ASTM D-6007-02- small chamber and ASTM E-1333-96 (2002)- large chamber, with a few 

exceptions mentioned and justified in the report (e.g., lower concentrations for calibration 

curve, greater conditioning period for the small chamber). The study used adequate 

equipment to ensure operation within the parameters recommended by the standard 

methods; 
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Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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 Tests are performed by an accredited TPC laboratory approved by CARB;

 Tests were well conducted based on an equilibrated test design.

 The products used were veneer core HWPW panels labeled as NAF and ULEF panels, 

selected by EPA as representative for ULEF composite wood products category.

Quality Assurance/Quality Control:

There were clearly specified measures taken to ensure the results accuracy by the following:

monitoring the equipment (measuring the chambers’ parameters), control in the process (accurate 

records of all measurements), precision and clarity on sampling and analysis (fresh solutions, 

consistent over time in the preparation of calibration curves), etc.

2. Are the results presented clearly and appropriately?

Results: 

 The results are clearly presented with adequate reporting of statistics and appropriate use of 

tables. 

 Interpretations and explanations are provided in detailed, mentioning also the unexpected 

results (large/small chamber comparison results at elevated T and RH conditions, ULEF-PF 

behavior at 70% RH). 

 Tables and figure facilitate comparisons, better understanding of results and drawing 

conclusions.

 The results are in reasonable agreement with the findings in literature.

III. SPECIFIC OBSERVATIONS

Page Line Comment or Question

5 Section 3.1

-line 1

- Why only veneer core HWPW panels? What about the other 

category of HWPW –with composite core? 

- Are the tested resins ULEF-UF, PF and NAF-acrylic 

representatives for the HWPW manufacturing? 

-line 3-4 - How were the elevated test conditions chosen (300C temperature, 

respective 85% relative humidity)? 

-line 10 - Why didn’t E1333 constitute the basic standard for tests instead 

ASTM D6007? 

5-6 Section 3.1.1

-line 8, page 5 

- This equivalency test made by TPC on July 2012 can be used no 

matter the product types? 

- Would be interesting to have these results of equivalency shown in 

a table as an annex or after Table 2 in Chapter 6, for comparison.

-line 12, 

page 6 

(paragraph 3)

- The sample dimensions (for test in the large chamber) are not 

given; it is mentioned only the product loading ratio of 0.43 (m2/m3) 

(on page 8) as is recommended for Industrial Hardwood Plywood 

Panels; 

- The sample for the large chamber was from the same batch as the 

boards tested in the small chamber?

8 Section 3.2

- line 5

- It was considered less important the use of the same thickness for 

all panels due to that only exposed surface areas were taken into 
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Hardwood Plywood Panels under Different Conditions of Temperature and Relative Humidity

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Page Line Comment or Question

consideration in the emission rate. The same unit measure for all 

thicknesses would have be better.

8 Section 3.3.1 - How long was the sample in the large chamber tested? The 

standard mentions 16-20 hours!

11 Section 4.3

-line 1

- It should be noted that these low background levels are below the 

values indicated in the ASTM E1333 and D6007 methods (0.03 ppm 

respective 0.02 ppm); this note should be added in section 3.1.1 page 

6 line 3.

13 Section 6.1

- line 9

-line 16 

(end of page)

- As I have already mentioned before, for comparison, it would be 

better to add the results for equivalency obtained by TPC in July

2012 for standard conditions. 

- Requirements for that equivalency are referred only for standard 

conditions. The equivalency large/small chamber for higher 

conditions cannot be applied.

15 Section 6.2

-line 4

- To clarify this issue with ULEF-PF panel, the test at high RH 

should be repeated.

15 Section 6.2.1

-line 3

- To have a clear evidence of comparison made (for each pair of 

resin types), it should be added if possible, a table with these results.