krclin~ Performance Applied 

June 25, 2012 

Ms. Lynn Vendinello 

Chief, Fibers and Organics Branch 

Office of Pollution Prevention and Toxics 

U.S. Environmental Protection Agency 

1200 Pennsylvania Ave. N.W. 

Washington, D.C. 20460 

RE: New Data Supporting Critique of Frihart Study 

Dear Ms. Vendinello, 

On January 10, 2012 Georgia-Pacific Chemicals submitted a critique of the study entitled Formaldehyde 

Emissions from ULEF and NAF Bonded Commercial Hardwood Plywood as Influenced by Temperature 

and Relative Humidity ("Frihart study"). The critique was submitted on behalf of GP Chemicals, LLC, 

Momentive and Ardin, Inc., the three major formaldehyde-based resin producers in North America. The 

letter explained our concerns with the relevance and condusions of the Frihart study and respectfully 

requested that EPA refrain from basing any rule-making decisions on the study's findings . 

In further support ofthe concerns outlined in the January 10th critique, a new study was conducted by 

Ardin, Inc., Particleboard Formaldehyde Emissions and Decay under Elevated Temperature and Humidity 

Conditions. As detailed in the attached document, the new Ardin study uses accepted regulatory and 

industry testing practices and is thus far more relevant than the Frihart study. The Ardin research 

dearly shows under extreme environmental conditions that all panel emissions were generally 2-3 times 

greater than "standard conditions" for adhesive types, and further that the emissions decayed 

significantly at a similar rate for adhesive systems in both the extreme and the standard 

environmental conditions. Most Significantly, panel emissions from all products under extreme 

conditions were well within California Air Resources Board Phase II emission levels within 25 days from 

date of panel making and exposure of the panels to an extreme environment did not adversely affect 

emissions when the panels were re-equilibrated to standard ASTM D-6007 conditions. 

Based on the Arclin study findings, we recommend that the EPA maintain a performance based standard 

aligned with the California Air Resources Board (CARB) ATCM, including provisions that foster and open 

and unbiased competitive environment for both resin and panel producers, allow choices and 

availability to consumers, and enhance innovation of all adhesive types. 

The Ardin and Frihart studies both attempted to better understand the impact on formaldehyde 

emissions from different adhesive systems when subjected to extreme environmental conditions. 

However, the Ardin study differs significantly from the Frihart Study in that it employs test methods, 

procedures and protocols that are more similar to actual in service conditions as well as consistent with 

475 28th Street. PO Bol( 270· Springfield. Oregon 97477 . USA . P 541.746.6501 f541.746.6273. \WIV.'. j Leorn 
CARB approved and industry accepted practices. The new Ardin study addresses the deficiencies in the 

Frihart study as follows: 

1. 	 Emissions test method: The emissions data collected in the Frihart study used a modified EN 

717-3 method. The EN 717-3 has not been approved by CARB nor is there an established 

correlation between the EN 717-3 method and the ASTM E-13331

. The Ardin study uses the 

ASTM D-6007 testing method which is approved for direct correlation to the ASTM E-1333. 

2. 	 Static versus dynamic equilibrium: The Frihart study used a static or stagnant testing 

environment which does not represent product emissions expected in normal use. The ASTM D6007 method used by Ardin is a dynamic test method in which a state of equilibrium is reached 

using a designated number of air exchanges reflecting normal indoor environmental conditions. 

3. 	 Extreme conditions of testing: The Frihart study used unrepresentatively extreme floutdoor" 

temperature and humidity test conditions. The Ardin study used a temperature of 85°F and a 

relative humidity of 75%. The Ardin test conditions are also extreme, but were based on an 

actual worst case scenario. Specifically, the worst case city (Houston, Texas), which has an 

average summer temperature of 84°F and relative humidity of 76.5%. Since temperature and 

humidity vary cydically throughout the day, the average of the daily low and high were used. 

4. 	 Ratio of edge to surface during testing: The Frihart study does not test products in a way that 

would be representative of how panel surfaces are exposed in actual use. In the Frihart study, 

there was extremely high edge exposure of the panels thus potentially exaggerating emission 

results. The Ardin study tested panels realistically in a manner they would be utilized as defined 

by worst case scenarios in manufactured homes for panel loading as well as edge exposure 

(correlation to ASTM E-1333). 

5. 	 Emission decay over time : The Frihart study had no long term VOC emission decay data. The 

only data provided showed cumulative emissions over a four day period leading to speculation 

regarding potential emission results from UF resins . In contrast, the Ardin study does an indepth evaluation of how particleboard panels bonded with various types of adhesives perform 

over a much longer period of time. The Arclin data shows panel emissions from the moment of 

manufacturing through a 50 day period. Under extreme conditions, all panels regardless of 

adhesive technology, showed an initial 2-3 fold increase of emissions followed by a significant 

decay curve resulting in significantly low emissions by the end of 50 days. Additionally, when 

these same panels were equilibrated back to flstandard" conditions at the end of 50 days, they 

behaved identical to panels which had been maintained at standard conditions showing there 

were no adverse or detrimental effects on panel emissions when exposed to extreme 

conditions. Panel emissions from all products under extreme conditions were well within CARB 

Phase II emission levels within 25 days from date of panel making and all panels were the same 

1 ASTM E-1333 is the primary CARB approved test method used for emulating performance of wood based panels 

within interior and the test method mandated in Section 601, Part (a)(7) and Part (a)(10) of the Public Law 111-199 

for measuring forma ldehyde emissions. 

475 28th Street. PO Bm 2l0. Springfield. Oregon 97477. USA. P 541.746.6501 f541.746.6273. www... ciin .com 
emission level (approximately 0.025 ppm or less) at standard conditions after a 45 day decay 

period. 

6. 	 Information on UF resin: The Frihart study provides no information on the UlEF-UF adhesive 

formulations or panel making procedures reducing Frihart conclusions regarding emission 

phenomena and hydrolysis concerns to nothing more than speculation. The Arclin formulations 

of the formaldehyde-based systems were known by the authors, and when possible CARB 

exempt "certified" UlEF adhesives were chosen for evaluation. 

The Arclin study used responsible testing methods and parameters to better understand the emission 

characteristics of panels made with various adhesive types. The study showed the emission 

characteristics of panels made with various types of resins, when exposed to standard and extreme 

environmental conditions, respond in a similar and predictable manner. 

Because of the similarities in performance of panels made with adhesive types, we endorse an 

unbiased performance based product emissions standard for regulatory purposes for all panel producers 

and resin suppliers. Additionally, we request the EPA refrain from using the Frihart study as a basis for 

justifying any regulatory decisions. 

Regards, 

-=~~ Technical Director 


Decorative and Interior Resins 


tom.holloway@arclin.com 

4TS 28th 511eet - PO 800. 270· Springfield. Orego,", 97417 • USA , P 541.746.6501 fH1.74li 6213 • WNW .rom 
Particleboard Formaldehyde Emissions and Decay under Elevated 


Temperature and Humidity Conditions 

Darren Riedlinger, Pierre Martin and Tom Holloway 

Arclin LiSA, 47528111 St. Springfield, OR 97477 

March 28, 20J2 

Abstract 

Particleboard panels were prepared using four different resin chemistries: melamine-ureaformaldehyde, urea-fonnaldehyde, phenol-fonnaldehyde, and polymeric diphenylmethane 

diisocyanate. Matched panels of each chemistry where then exposed to either a control 

conditioning environment maintained at 77 "F, 50'% RII or an elevated conditioning 

environment maintained at 85 OF, 75% RH. Emi%ions were monitored over 50 days and their 

respective decay rates \vere modeled as an exponential decay function. At the conclusion of the 

monitoring period panel physical properties were measured and compared. 

Key words: Particleboard, formaldehyde emi~sions 

Introduction 

Product emission standards based on ASTM 

E 1333 for composite panels have hIstorically 

been tested at humidlties and temperatures 

standardized to average indoor environmental 

conditions. This paper examlnes formaldehyde 

emissions from particleboard made with various 

adhesive types tested under extreme conditions 

over a 45-50 day period using a modified 

ASTM 6007 method. Environmental 

conditions during testing \vere based on high 

outdoor temperature and humidity conditions 

experienecd during summer months in the 

Southeastern Cnited States (1). Since 

temperature and humidity vary cyclically 

throughout the day, the average of the daily low 

and high experienced in the most extreme 

summer location was used for the experimentcorresponding to a relative humidity of75% ami 

a temperature 0[85 CF. 

Laboratory made particleboard panels, 

conditioned and tested for emissions, were 

bonded with four diffcrcnt adhesive types: a 

pbenol-fonnaldebyde (PF) certified to meet 

California Air Resource Boards (ARB) ultralow-emitting-fonnaldehyde (ULEF) standard, a 

polymeric diphenylmethane diisocyanatc 

(pMDI), a urea-formaldehyde (UF) and a 

melamine-urea-formaldehyde (.\IIUF). 

Experimental 

Panel Construction 

Laboratory panels were made from wood 

furnish gathered from a pal1icleboard plant 

which manufactures panels using only pMDI 

adhesives, ensuring the furnish would be free 

from panel recycle sources (mitigated as much 

as possible) that may have an influence on 

fomlaldehyde emissions. Sixteen panels total 

WIth four of each adhesive type were 

constructed. Panels were made With 50% 

surface material and 50% core material to a 

targeted density o[ 44.0 pounds per cubic foot. 

All panels were /2 inch nominal thickness \'lith a 

targeted final thickness of 0.570 inches. Press 

temperatures were held constant at 345 OF for all 

adhesive types. The pMDI and amino resin 

systems v,·ere pressed with identical cycle-times; 

Page 1 0[8 
however, the pMDI panels had slightly higher 

moisture contents to ensure cure. The only 

variance in press time was with the PF in which 

a longer cycle-time was used to ensure curing of 

the adhesive. None of the panels were sanded 

prior to formaldehyde testing. 

Although exact adhesive and panel making 

recipes for these panels will not be revealed due 

to the proprietary nature of the adhesives and 

recipes, the MUF, PF, and pMDI represent a 

close approximation to recipes used in the 

composite particleboard panel industry. The UF 

was made at the same formaldehyde to urea 

ratio as the MUF and with the same panel 

making recipe, however, it has not been used 

commercially. Some panel making 

characteristics are presented in Table 1. 

Table 1: Panel making details 

Adhesive Press Press time Density Thickness 

type temp. at position (lbs·lft· .) (in.) 

(1F) (sec) 

PF 345 240 43.15-43.80 0.572-0.573 

UF 345 170 43.85-44.40 0.570-0.571 

MUF 345 170 43.95-44.25 0.568-0.570 

pMDI 345 170 44.00-44.65 0.566-0.568 

Formaldehyde Emissions Testing 

After removal from the hot press and 

cooling to ambient temperatures, one set of 

panels was cut into 6.75 x 6.75 inch samples and 

edge sealed using aluminum tape. They were 

then sealed in a polyethylene bag for later 

analysis in Arclin's Springfield, Oregon 

laboratory which had environmental conditions 

of 85 of (29.44 0C) and 75% relative humidity. 

A duplicate set, treated similarly, were cut to a 

dimension of 7.87 x 9.06 inches and sent to 

Arclin's Ste. Therese, Quebec lab for testing 

using standard ASTM 6007 environmental 

conditions of 77 OF (25°C) and 50% relative 

humidity for comparative purposes. Each 

testing environment consisted of an outer 

conditioning room containing one or more 

stainless steel testing chambers, capable of 

maintaining fixed airflow rates during emissions 

testing. Testing of all panels began once both 

labs received their samples and continued at 

periodic intervals thereafter. Because the two 

testing environments utilized in this study were 

located in different research laboratories--each 

with unique infrastructure and analytical 

capabilities, some slight differences existed in 

the respective methodologies. 

For the control environment, a single 

Dynamic Micro-Chamber (DMC) was 

employed with an internal volume of 44 liters. 

The airflow rate was maintained at 3.60 Umin, 

resulting in ASTM D 6007 airflow-rate to 

sample-surface-area ratio (Q/ A) of 1.173 rnlh. 

Panels were stored in individual conditioning 

bays located within the conditioning 

environment between analyses and were 

transferred to the DMC between 10 and 30 

minutes before sampling. During sampling, 1.0 

Umin of the chamber make-up air was diverted 

into an impinger containing 20 ml of a 1 % 

solution of sodium bisulfite for a period of 83 to 

135 minutes. Immediately after sampling, two 

duplicate 4 ml aliquots of each impinger 

solution were reacted with chromotropic acid 

and analyzed using a Spectronic 301 

spectrophotometer at 580nm, which had been 

previously calibrated using a series of 

formaldehyde solutions of known concentration 

(R2 = 0.999). Background formaldehyde levels, 

tested periodically throughout the test were 

consistently below 7 parts per billion. 

For the elevated temperature/humidity 

environment, four ASTM D 6007 small 

chambers were employed, each having an 

internal volume of 69.24 liters. Mass-flow 

controllers attached to the outlet port of each 

small chamber maintained an airflow rate of 

1.152 Umin, resulting in an ASTM D 6007 Q/A 

ratio of 1.176 m/h. Panels were stored in 

individual conditioning bays located within the 

conditioning environment between analyses and 

were transferred to a randomly chosen small 

chamber five hours before analysis. Following 

equilibration, air sampling occurred over 60 

minutes, during which time airflow was diverted 

from a bypass line to a Supelco S 1 0 DNPHPage 2 of8 
coated sihca solid phase extraction column 

(sampled air volume equaled 69.2 . ,i_ O.Iliten). 

The cartridges \vere then sealed in Mylar bags, 

stored at 5 "C and anal~i7ed by IIPLC within 

one week. Both room and small r.;hamher 

background formaldehyde In d~ were measured 

periodically throughout the expenment and were 

consistently bell)\\. 3 parts per hl1lion. 

IIPLC fOlmaldehyde quantification \/vas 

pcrfonned uSll1g an adaptation of l\lOSll 

:V1cthod 2() 16. HPLC peak area response factors 

were calihrated for each analysis set lIsmg five 

D'\IPH-formaldehyde standards at 

concentrations between o15S6 and 96.9 flg 

D'\IPH-formaldehyde per ml. Linear regress10n 

coelTic1ents were greater than 0.')9')9 for all 

analyses. 

Measured fonnaldehyde emi:.~i()ns are 

expre)sed in molm ppm, adjustcd to con"elate 

w1th the ASTM E1333 large chamber dynm11lc 

test method. This corrdation was performed 

het\\'een Ardin· s Springfield laboratory and the 

Compo~ite Panel Association's 1..:.1333 large 

chamher ming 12 sets of matched sper.;1I11en 

'whose emissions ranged bctwcen D.D 1 and D.15 

ppm. A correlation factor of 0.7775 largecham her ppm-'small-chamber ppm was 

established with an R2 equal to O.9H7. A later 

eOlTelation study vv'as then pcrfonned hetween 

Arelil1·~ Springfield and St. Therese laboratories 

using 12 specimens whosl: l:111lssions ranged 

hetween 0.01 and 0.11 ppm. In thi:. l:ase, t\\,oway linear rcgrr.;ssiun of the two laboratories· 

111easurcmellts yielded a :.igmfieant (P < .DOO 1) 

intercept eoefllcient and the St. Therese values 

were adJu~ted mmg the fol1ov>':ing correlation 

equation (R= - (J.971 H): 

[1] Springfield [1333 ppm - (11441 x 5t, Therese ppm)­

001185 

Results and Discussion 

Control envirunment /ormaldehvde emissiolls. 

Dynamic-airflow fonnaldehydl: emi:.~i()ns 

for particleboard panels maintamed at 77 ~F and 

50(% Rll arl: presented 1n F1gure 1. Each panel 

~ct had been sealed in polyethylene immediately 

after pressing and 1nitml measurements INere 

taken less than one hour after unsealing. ror all 

four resin chemistries, this initial emisslOns 

measurement was significantly eir.;\-atr.;d relatlve 

to mbsequent samples and can likely he 

attributed 10 the n:kase of entrained 

formaldehyde, which i~ tYP1Gtl when panels are 

scaled immediately after hot-pressmg. For 

example, the .MUr and LF-honded paneh 

initially generated emissions orO.llS and 0.097 

ppm. respecthely, but had fallen to hetween 

0.045 and 0.OS5 ppm after two day~ of 

conditioning and then declmed steadily 

throughout the study. By the end the 

monitoring pcnod, cm1SSlOns from the \IUF 

panel were O.(J24 ppm and em1SSIO[lS from the 

lJF panel were 0.013 ppm-both well helow the 

AR13 phasl: II limit. The PF and pMDT-bonded 

panels also exhib1ted relatively hIgh emissions 

tor the imtial me1bUfement and decayed to 

0.014 and 0.023 ppm. re~pcr.;tlvely, after two 

day:. of conditionmg. Ultimate emission levels 

aner 50 day~ of monitormg were D.O(l3 ppm tor 

the pMDI panels and ncar ;tern ppm for the PF 

panch. A:. pMlJI con tams no labile 

formaldehydc, the p:\1DI panels" emissions 

represent background levels arising solely' from 

the \\oml fUJ111Sh used !Il thi5 ~hldy---either 

cndogenom formaldehyde generated by wood 

itself(and po~sibly exacerbated by hot-pres:.mg) 

(2-4), or from formClldehyde containing recycle 

materi;ll in our source mill"s fum1sh supply 

(despite our efforts to mitigate ib prcscnce). It 

is therefore notcworthy that the phellol!e re5in 

sy:.tem. although not a non-added formaldehyde 

(l\AF) :.ystem, cons1~tently exhibited lov,cr 

eJlllssions than the pV1DI system. 

Pagc 3 ors 
- - - - - -

§0.14 

~ 0. 12 

' UJE0. 10 •,. - - ­ "0 

2J 0.08 

'" 

~ 0.06 , • • • 5 

u 0.04 -

'" 

MUF 

• UF 

0 pMDI 

• PF 

~ 0.02 ------- y .... • UJ O. OO~_ __ _ _ __~O__~~- - _ ~ __ . ~ ~~~_ _ ~ _ ~ ~~ _ _ _ _ _ ~~_ _ _ ~ __ _ ~~~ . _ _ ._ _ _ ~~~ _ _ 

o ill m ~ ~ ~ 

Conditioning Time (days) 

Figure 1: Particleboard emissions decay rate under standard temperature and relative humidity conditions 

Temperature %RH 

J: 85.0 T- T f - - t ft · cc: *-

u: 75.0 ~ ~ ~ 9 t ~ M I 1 I I 

• 65 .0 " VI g 0.14 ,. MUF 

~ 0.12 UF

E •

.. 

•.. 

• • 

., w 0.10 ­ pMDI "0 . •

2J 0.08 - PF I!!I ­ • '" ~ ~ 0.06 o t·· " ~ 

u 0 - - - - 0 ---_. __.- - - - - .. .04 • - - - • - - - - - ­

'" 

~ 0.02 ··dI •.. 1ItJ 81 tJ . • Q . 9 ­ I .... • UJO.OO~_____ ·- - - ______~~~ - - _~ ~~~~ ~~ ~ ~~ ~ ~~~ - -~~ ~ ~~'- -' ~_ - -~ ~~' ~ ~ ~~~ -- ~~ ~~~ -. 

o ill m ~ ~ ~ 

Conditioning TIme (days) 

Figure 2: Particleboard emissions decay rate under elevated temperature and relative humidity conditions. 

Top: Room (solid lines) and small chamber (discrete box plots) temperature and humidity data. Box plots represent the 

minimum, lower quartile, median, upper quartile and maximum small chamber condition observed during each 60-minute 

board sampling. Bottom: E1333 correlated small chamber emissions for particleboard panels prepared using MUF, UF, 

pMDl or PF adhesives. ' Solid' versus 'open' data points distinguish between each of two replicate panels manufactured and 

analyzed for each resin type. 

Elevated environment formaldehyde emissions: 

Formaldehyde emission levels for those 

panels maintained at 85 OF and 75% RH are 

presented in Figure 2. Under these conditions 

our environmental controls were not as precise 

as those used for the 77 OF, 50% RH 

conditioning environment; therefore, actual 

temperatures and relative humidities of the room 

and small chamber are provided in the upper 

portion of Figure 2. Over the course of the 

entire monitoring period, the average 

conditioning room temperature was 84.1 OF (0' = 

1.74) and the average room humidity was 

73.6% (0' = 8.88). Unlike the temperature of the 

conditioning room, which could be maintained 

close to its average value with only occasional 

deviations, the conditioning room humidity 

oscillated regularly with approximately three 

cycles per hour. However, the small chambers 

buffered these oscillations and remained 

relatively constant: during sampling, the average 

conditions within the small chambers were 86.2 

OF (0' = L.03) and 74.7% RH (0' = 2.71) . 

As illustrated in Figure 2, although all 

panels (at least initially) generated higher 

emissions in the 85 OF, 75% RH elevated 

environment than in the 77 OF, 50% RH control 

environment, the relative trends were the same: 

the amino-based chemistries (MUF and UF) 

exhibited the highest emissions, the pMDI 

system was intermediate and the PF systems 

emissions were lowest. During the initial two 

days of conditioning the emissions from all 

panels declined. However, between days two 

Page 4 of8 
Figure 3: Comparisons of emissions in elevated and control environments, overlaid with exponential decay 

models 

E 

Q. 

.3­

V> 

c 

o 

~ E 

w 

-0 

2 

'" 

~ o 

U 

'" '" rl 

W '" 

and four, emissions actually increased slightly in 

all panels- a phenomenon not observed in the 

control environment. In the 75% RH elevated 

environment, panels would likely take longer to 

approach their equilibrium moisture content 

than in the 50% RH control environment, and 

this may suggest that increasing panel moisture 

was counteracting an otherwise natural decay in 

emissions over time. Following day four, the 

emission levels from all panels again begin to 

decrease, with the magnitude of this decrease 

being greatest in the higher emitting systems. 

For example, at day four emissions from MUF 

and UF -bonded panels were both approximately 

0.13 ppm and decreased steadily throughout the 

remainder of the 45-day monitoring, ultimately 

reaching levels below 0.06 ppm. Emissions 

from the pMDI panels were near 0.06 ppm at 

day four and decreased to approximately 0.027 

ppm by the end of the study. Lastly, emissions 

from the PF panel, which were already below 

0.03 ppm after four days conditioning, 

decreased to 0.023 ppm by the end of the study. 

0.14 -

0.12 

0.10 

0.08 

0.06 

0. 04 

0.02 

0.14 

o 0 

0.12 ~O 

' '(J0,S 0 

0.10 (JI'" cO, 0.08 0 "be.. 

0.06 

• • 0.04 

0.02 

• pMOI (ontrol 

o pMDI elevated 

0" - _-JQ. 

o • o --­ ::: 

Conditioning Time (days) 

Emissions decay modeling and comparison: 

From the raw data presented in Figures 1 

and 2 alone it is difficult to make direct 

comparisons between emissions in the elevated 

environment and control environment at specific 

points in time, due to both noise in the datasets 

and a lack of measurements at identical 

conditioning times in the two environments. 

Panel formaldehyde emissions have generally 

been observed to decay exponentially with time 

(5). Each dataset was therefore fitted with an 

exponential decay function to average out 

measurement errors associated with any 

individual datapoint and allow us to interpolate 

emissions levels at arbitrary points in time. 

Model coefficients and fitting details are 

provided in Appendix A. 

Emissions in the elevated and control 

environment are compared for each resin in 

Figure 3 and are overlaid with the fitted 

exponential decay models. Based on these 

models, emissions levels after 7,30 and 45 days 

were calculated and are provided in Table 2. 

Relative emission differences for the MUF, UF 

Page 5 of8 
Table 2: Calculated emissions values based on the exponential decay models at various conditioning times. 

For each conditioning time the relative difference between the elevated and control models (,ratio') and absolute 

difference (' f\.') are provided. 

Day: 7 30 45 

Resin control elevated ratio D. control elevated ratio D. control elevated ratio D. 

MUF 

UF 

PF 

pMDI 

0.057 0.109 

0.063 0.108 

0.011 0.027 

0.023 0.048 

1.94 0.053 

1.71 0.045 

2.55 0.016 

2.10 0.025 

0.035 

0.029 

0.002 

0.009 

0.068 1.93 0.033 

0.067 2.35 0.039 

0.021 10.05 0.019 

0.023 2.63 0.014 

0.026 0.050 1.93 0.024 

0.017 0.050 2.88 0.032 

0.001 0.018 22.50 0.017 

0.005 0.014 3.02 0.009 

and pMDI systems were similar, with emissions 

in the elevated environment being 

approximately two- to three-times higher than in 

the control environment, regardless of 

conditioning time. However, because emissions 

decayed exponentially over time, the actual 

magnitude of the emissions difference between 

the elevated and control environment (~) also 

tended to decrease exponentially. Unlike the 

MUF, UF and pMDI systems, the ratio between 

the elevated and control emissions for the PF 

system increased throughout the study, with a 

22.5-fold difference in emissions after 45 days. 

Note, however, that emissions from the PF 

control system were extremely low; this unique 

trend observed for the PF panels could in part 

relate to greater measurement errors as 

emissions approached our analytical limits of 

detection. 

Panel re-equilibration and physical properties: 

Finally, after 50 days of conditioning our 

Springfield testing environment was adjusted 

back to the control conditions of 77 OF and 50% 

RH and those panels previously maintained in 

our St Therese control environment were 

shipped back to Springfield. These panels, 

along with the panels previously exposed to the 

elevated environment, were re-conditioning in 

Springfield for seven days and their emissions 

are presented in Table 3. The Springfield 

emissions measurements for the control panels 

(column iii) are similar to final measurements 

made in St. Therese (column i), indicating good 

agreement between the two laboratories. 

Furthermore, after equilibrating to 77 OF, 50% 

RH, emISSIOns from those panels previously 

maintained in the elevated environment (column 

iv) were almost identical to the final emissions 

from the control panels (column iii), suggesting 

that exposure to elevated temperatures or 

humidities does not permanently alter a panels 

emissions characteristics. 

Although panel emISSIOns were not 

permanently affected, conditions in the elevated 

environment were severe enough to affect all the 

panels' physical properties. After reequilibrating for 7 days at 77 OF and 50% RH, 

internal bond (IB) strengths were measured for 

both the control and elevated conditioning 

environment panels. IE values of those panels 

exposed to the control environment met M-2 

grade ANSI standards, with the exception of the 

UF resin which only met ANSI M-l grade. In 

contrast, IE values of all panel chemistries 

exposed to the elevated environment were 11­

15% lower and exhibited some surface quality 

issues related to raised grain. 

Table 3: Panel emissions in Springfield 

laboratory at 77 OF, 50% RH 

ii iii iv 

Resin St. Therese Springfield Control, re-tested 

(control) (elevated) in Springfield at 

final final 77°F, 50% RH 

Elevated, reconditioned to 

77°F, 50% RH 

PF 

pMDI 

UF 

MUF 

0.001 0.023 0.008 

0.003 0.028 0.009 

0.013 0.059 0.019 

0.024 0.055 0.021 

0.010 

0.010 

0.021 

0.022 

Page 6 of8 
Conclusions 

Pilrticiehoard p;mcls ",,:ere prepared usmg 

four different re~1I1 chemistries and their 

emissions were monitored over 50 days in both 

a 77 "F, 50% Rli control conditioning 

environment ami a X5 cr, 75%) RH elevated 

environment. The elevated conditionmg 

cnvmmment had moderatc effect on panel 

phY~lcal properties, negatively Impacting 

surface quallty and slightly reducing Internal 

bond strengths. While subjected to the elevated 

environment. emissions \vere generally 2-3x 

greater than what was observed in the control 

environment hO\veyer, In both em· lronments 

panels cm1SS1011~ decayed exponentially 

throughout the study regardlc:.>, of resin 

ehcmi~try. Furthcnnore, the elevated 

conditioning environment did not appear to 

permanently Impact emi~sions once these panels 

were re-equilibrated in a control environment. 

References 

I. F()rmaldehyde I:"missions .[rOI/J l./LL"Fand A'A F-Bondcd Commercial IIardw()od 

Plywood os Ili/lucnced h.Y' rCIl1/Jeratllrc and 

Reiatil)c HumidifY. Frihart, Charles R, ct at. 

()cncva, SwitLeriand, 2010. Proceedmgs of the 

International Convention of Soc let;.' of Wood 

SCIence and Tcchnology and LJlllted Nations 

EconomIc COmml~S]()n fi.n Euorpoe. pp. 1-13. 

2. FormaldehJdc cmissiol1.l'Fotn solid IHWt/. 

Myers, Gcorge E and Bochme, C. Macils()n, 

\Vr: Forest Prod. L 1997, Vol. 47, pp. 45-4X. 

3. Volitilc organic compollndl' Ilnd 

jurma/deh.Y'de il7 nature, 'rvood and H'oud based 

panels. Rotlael, E. :..1.' Holz Koh vVcrkst, 

2006, Vol. 64, pp 144-149. 

4. fVoor/-bol"})e fi'Jrmaldchyde vw)'ing l,vith 

.Ipecie.l", \-vood ;.!,mde, and c(Jl11hial age. \Ycigl, 

M, et al. s.l. . Forest Prod. J , 200t), Vol. 59, pro 

XX-92 

5. Versar Inc. Formaldehyde exposure 

model -- descriptio/l (jnd del1JolIstmlio/J. CS 

Environmental Protl:ction Agl:l1cy, 1986. 

Contrad l\o. 68-02-3968. 

Page 7 or8 
Appendix A: Formaldehyde emissions decay modeling 

Panel emissions were modeled to the exponential decay functiont: LoglO{emissions) =M . time + B, 

resulting in the following model coefficients and regression values: 

Treatment 

MUF elevated 

MUF control 

UF elevated 

UF control 

pMDI elevated 

pMDI control 

PF elevated 

PF control 

Slope Intercept R2 

-0.0091 -0.8976 0.923 

-0.0090 -1.1850 0.782 

-0.0089 -0.9053 0.886 

-0.0149 -1.0951 0.889 

-0.0140 -1.2246 0.752 

-0.0183 -1.5161 0.697 

-0.0047 -1.5356 0.604 

-0.0302 -1.7654 0.951 

Model R2 values are generally lower for those treatments that generated the lowest formaldehyde 

emissions, reflecting the greater relative error associated with emissions measurements as they approach 

background levels and suggesting the need to smooth such datasets before making reliable comparisons. 

Despite the low model R2 values for some treatments, visual examination of Figure 3 suggests that the 

exponential decay model provides a good approximation of the overall emissions trend for each 

treatment without overfitting the data and modeling random variations associated with any individual 

data point. 

t In the case of the PF control emissions, three of the emissions measurements-after adjusting according to 

Equation i-were slightly below zero (the minimum observed value was -0.00096 ppm) and could not be modeled 

by an exponential decay function. These three negative emissions values were excluded from the PF control 

emission model. 

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