3 

Formaldehyde Release from Wood Panel Products 

Bonded with Phenol Formaldehyde Adhesives 

J. A. Emery 

American Plywood Association, 7011 South 19th Street, Tacoma, WA 98466 

Both the published literature and previously unpublished 

information obtained by the structural panel industry 

indicate that formaldehyde levels associated with panel 

products glued with phenol formaldehyde adhesives are 

extremely low. Large dynamic chamber tests which simulate conditions that might be found in tightly sealed 

residences indicate consistently that formaldehyde 

levels associated with freshly manufactured phenolic 

panel products are less than 0.1 parts per million. The 

data, as well as theoretical considerations, also indicate that the amount of formaldehyde contributed to the 

environment by phenolic panel products should rapidly 

approach zero as the small quantity of formaldehyde initially present in the products is released. 

Virtually all wood panel products such as plywood and particleboard 

are manufactured using either urea formaldehyde or phenol formaldehyde adhesives. Urea formaldehyde adhesives are used in hardwood 

plywood and in certain types of particleboards. These adhesives are 

not waterproof, and products made with them are normally used indoors 

for paneling, furniture, shelving and floor underlayment. 

Phenol formaldehyde, on the the other hand, is used to make the 

waterproof adhesives that are used in structural wood panel products 

such as softwood plywood, oriented strand board, waferboard and 

exterior (phenolic) particleboard. These products are commonly used 

for roof, floor and wall sheathings, exterior sidings, concrete forms 

and in pallets and numerous other products. 

Although formaldehyde emissions from some products glued with 

urea formaldehyde adhesives can cause indoor air quality problems 

under certain conditions, such problems have not been associated with 

phenol formaldehyde-bonded (phenolic) products. Unfortunately, 

however the commonplace usage of the generic terms "particleboard" 

and "plywood" has failed to distinguish between product types and has 

led to a great deal of confusion among consumers. 

Because phenolic panels have not presented formaldehyde-related 

problems in the marketplace, there has not been much need to develop 

information on formaldehyde emissions from these products. 

0097-6156/86/0316-0026$06.00/0 

© 1986 American Chemical Society 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 

This material may be protected by Copyright Law [Title 17 US Code]
3. EMER Y Wood Panel Products Bonded with Phenol Formaldehyde Adhesives 27 

Nevertheless , a considerabl e amount of informatio n has been generated 

to satisf y curiosit y and to answer inquirie s concerning emissions 

from phenoli c panel products. This informatio n i s summarized i n thi s 

paper under three primary subject headings: (1) Theoretica l Considerations ; (2) Literatur e Review; (3) Previousl y Unpublished 

Information. 

Theoretica l Consideration s 

The chemical and physica l characteristic s of phenoli c resin s and 

adhesives made from them suggest that formaldehyde emissions should 

be very minor (_1_) . One reason fo r predictin g low emissions i s that 

very littl e residua l fre e formaldehyde i s present i n prepared phenoli c resins . Thi s low fre e formaldehyde content i s due to both the 

use of low formaldehyde to phenol mole ratio s i n resi n preparatio n 

and to the tendency of nearl y al l the formaldehyde to reac t 

irreversabl y with the phenol. 

Another reason fo r predictin g low emissions i s that the small 

amount of residua l formaldehyde that might be present i n the prepared 

resi n i s diminished even farthe r by reaction s which occur when the 

resi n cures. Phenoli c resin s are cured under heat and pressure i n a 

hot-press , usuall y under highl y alkalin e conditions . Curing temperatures are usuall y i n the range of 130-220°C. Under these conditions , 

unreacted formaldehyde continues to reac t with phenol to form large r 

phenol formaldehyde polymers. Also , some formaldehyde react s with 

variou s chemical constituent s i n the wood. Moreover, some formaldehyde i s probably converted to methyl alcoho l and formic aci d by way 

of the Cannizzaro reactio n (JO . 

A thir d reason fo r predictin g very low emissions of formaldehyde 

from phenoli c panels i s that the cured resi n i s extremely stabl e and 

does not break down to releas e additiona l formaldehyde, even under 

extremely harsh environmental condition s (2) . The high resistanc e of 

phenoli c resin s to deterioratio n under severe servic e condition s is , 

of course, a principa l reason they are used so widely i n making exterio r types of wood panel products. Because of thei r chemical 

stabilit y the U.S. Environmental Protectio n Agency has declare d that 

phenol formaldehyde resin s represent a "consumptive use" of formaldehyde, meaning that formaldehyde i s irreversibl y consumed i n it s reac -

tio n with phenol so that the formaldehyde lose s it s chemical identit y 

(3) . 

Any formaldehyde that might be present initiall y i n fres h 

phenoli c panels, would be expected to diminis h through time, sinc e 

additiona l formaldehyde i s not release d from a breakdown of the res -

i n . Thus, barrin g contamination from other sources, formaldehyde 

emissions associate d with thoroughly aged phenoli c panels should be 

nil . 

Literatur e Review 

The formaldehyde emittin g potentia l of wood panel products can be 

evaluated i n numerous ways, includin g the use of dynamic chamber 

test s (test s involvin g chambers which are ventilate d and simulate 

real-worl d conditions) ; stati c (unventilated ) tests , such as 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
28 FORMALDEHYD E RELEAS E FRO M WOO D PRODUCT S 

desiccato r and "equilibriu m jar " methods; and chemical extractio n 

tests , such as the European Perforato r Test . This review wil l emphasiz e the result s from dynamic chamber tests , especiall y the "larg e 

scale " dynamic chamber test , sinc e the result s of such test s can 

generall y be compared and sinc e the result s are more representativ e 

of real-worl d situation s than are the result s of other tests . Data 

from stati c test s and chemical extractio n test s are more abstrac t 

than the result s of dynamic chamber tests , and such data must there -

for e be correlate d with some type of dynamic tes t i n order to be usef u l i n terms of evaluatin g actua l potentia l exposures. 

Nestle r (4) thoroughly reviewed the worldwide literatur e on 

formaldehyde emissions from wood products published through January, 

1977. According to Blomquist (1_) , Nestler 1 s literatur e review in -

cludes only three citation s which even mention phenolic adhesives, 

and none of these citation s made specifi c mention of any problems 

associate d with the use of phenoli c panels. 

Since Nestler 1 s review was published , some additiona l informatio n on formaldehyde emissions from phenoli c panels has appeared i n 

the literature . Information obtained usin g dynamic tes t chambers i s 

summarized i n Table I. Perforato r and two-hour desiccato r data are 

summarized i n Table II . 

As indicate d i n Table I, dynamic chamber tes t data have been 

obtained i n investigation s usin g chambers ranging i n siz e from 

0.003 m3 (0.1 ft 3 ) to 28 m3 (1000 ft 3 ) . Besides thi s larg e chamber 

siz e variation , the studie s als o varie d widely with respec t to the 

temperatures, relativ e humidities , loadin g rates , and ai r exchange 

rate s used fo r testing . Because of the wide variation s among the 

studie s with respec t to these tes t parameters, i t i s not possibl e to 

make many inference s from the data presented. However, some general 

trends are evident , and certai n relationship s developed from studie s 

involvin g urea formaldehyde systems make i t possibl e to make a few 

generalize d observations concerning the data. 

Although Table I indicate s that formaldehyde level s ranging 

from 0.01 - 0.3 part s per millio n (ppm) have been observed i n studie s 

usin g dynamic tes t chambers, values of 0.1 ppm or lower were observed 

i n most of the investigations . Those studie s i n which the higher 

level s were found (i.e. , the firs t two studie s summarized i n the 

table ) used very small tes t chambers (0.003 m3 ) and relativel y high 

temperatures, humidities , and loadin g rates . Lower level s are shown 

f o r those studie s wherein the tes t parameters approximated "real -

world" condition s (larg e tes t chambers using temperatures, humidities , loadin g rates , and ventilatin g rate s approximating those found 

i n livin g areas) . 

The higher formaldehyde level s associate d with the firs t two 

studie s summarized i n Table I can probably be attribute d primaril y 

to the relativel y high temperatures employed. Numerous investiga -

tion s have shown that formaldehyde level s increas e exponentiall y 

with temperature (_5-_7) . Several studie s have shown that formaldehyde 

level s associate d with wood panel products can increas e by more than 

a facto r of 3 as the temperature increase s from 25°C to 40°C (8) . 

The exponentia l functio n developed by Berge, et.al , (5) i s commonly 

used to adjus t formaldehyde data fo r temperature (9^ . I f thi s functio n were applie d to the data of Table I i n order to adjust al l formaldehyde level s to a common temperature of 25°C, the correcte d level s 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
Table I. Summary of Publishe d Dynamic Chamber Test Data fo 

Dynamic Test Chamber Parameters 

Product Vol . Temp. R. H. Loading A i r Changes HCHO Level s 

Type^

1 ) (M

3 ) <°F) (%) 

(m2/m 3)?2) Per. Hr. (ppm)(3) 

PB .003 95 67 6.7 1.7-6.6 .05-.3<

4) Data 

on 4 

befo

90 d

.1 - 

.12-.18<

4) 

ppm 

PB .003 77-104 75 19.2 1.15 .12-.18<

4) Emis

boar

.1(4) 

temp

SWPW .21 77 50 .1-10 1-4 .1(4) Cham

from 

rate 

leve 

WB 28 75 50 .43 .5 .01-.04 Data 

24 s

.1,.06<« 

manu

WB 28 75 50 .43 .5,1 .1,.06<« The 

corr

.1,.06<*> 

vent

SPP 28 75 50 .43 .5,1 .1,.06<*> 

PB 28 75 50 .43 .5,1 .1,.06(*> 

(1) PB = particleboar d ; SWPW = softwood plywood; WB - waferboard; SPP = south

(2) Loading i s expressed i n terms of square meters of panel surfac e area per 

(3) Part s per millio n part s of air , volume basis . 

(4) Data value s taken from graphs. 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch00

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
Table II . Summary of Publishe d Two-Hour Des

and Perforato r Test Data fo r Phenoli c Pan

Product 

Type^

1 ) 

Formaldehyde Level s 

PB 

WB 

WB 

PP 

SWPW 

2-Hr. Desiccato r 

Qg/ml)(2) 

Perforato r 

(mg/100g)(

3 ) Remarks 

.11-.27 

1.09-1.37 

.16 

.29-.85 

Values repres

differen t par

boar as . 

Two hr . desic

values represe

on 45 samples 

manufacturers. 

values represe

l e s from 8 ma

.6 

.18 

(1) PB = particleboard ; WB = waferboard; PP = phenoli c plywoo

plywood. 

(2) FTM 1-1983 procedure (16) was used i n al l studies . Values 

of HCH0 per ml distille d water. In thi s tes t 25 ml disti

dis h i s placed i n desiccato r with eigh t 7 cm x 12.7 cm sp

the water i s then analyzed fo r formaldehyde. 

(3) Tota l HCH0 extractabl e with boilin g toluene, mg. formalde

wood (21). 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch00

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
3. EMER Y Wood Panel Products Bonded with Phenol Formaldehyde Adhesives 31 

would al l be 0.1 ppm or lower. Such an adjustment would make the 

emission data from the small chamber test s simila r to those from the 

larg e chamber test s summarized i n the table . 

I t i s important to note here that higher temperatures probably 

increas e emissions from phenoli c panels simply by acceleratin g the 

releas e of that small amount of residua l formaldehyde that originate s 

from the adhesive and subsequently becomes adsorbed to the wood substance and water i n the wood. Because phenoli c resin s are very 

stabl e chemically , any temperature-related increas e i n emissions 

would not be expected to be associate d with resi n degradation. 

Consequently, temperature would be expected to exert much les s 

influenc e on emissions from panels which have been aire d out than 

from fres h panels. Indeed, thi s trend i s shown by the data, as dis -

cussed below. 

The informatio n presented i n Table I als o indicate s that the 

loadin g and ventilatio n rate s fo r those two studie s i n which the 

highe r formaldehyde level s were found (8,10) were higher than fo r 

the other studie s summarized. The influenc e of these factor s on 

formaldehyde level s has not been clearl y explained , however, sinc e 

the amount of data pertainin g to phenoli c panels i s so limite d and 

sinc e the literatur e appears to be contradictory . Studies of urea 

formaldehyde-bonded systems generall y indicat e that emissions 

increas e with higher loadings and decrease with higher ventilatio n 

rate s (6,11). Moreover, Meyers (11) has shown that there i s ofte n 

a good relationshi p between the rati o of ventilatio n and loadin g 

rate s (N/L ratios ) and formaldehyde concentratio n i n controlle d chamb er experiments. Indeed, the data presented i n two of the studie s 

summarized i n Table I (10,12) appear to be i n general agreement with 

these trends, sinc e the data show decreases i n formaldehyde level s 

corresponding to increase d ventilatio n at constant loading . However, 

other studie s have indicate d that emission level s from very low emittin g products are not influence d significantl y by loadin g or ventila -

tio n rate s (6^). More researc h on these relationship s i s needed. 

The effec t of panel age on formaldehyde releas e was investigate d 

i n the firs t study summarized i n Table I, and thi s variabl e was evi -

dentl y very important with respec t to the formaldehyde level s 

measured. As noted i n the Remarks column i n the table , formaldehyde 

level s ranged from 0.1 - 0.3 ppm fo r freshl y manufactured specimens, 

whil e level s i n the range of only 0.05 - 0.1 ppm were associate d with 

matched specimens that had been aire d out fo r 90 days at 23°C and 

44% relativ e humidity. Thi s aging effec t i s consisten t with the 

theoretica l consideration s discusse d earlie r and with tes t result s 

to be presented late r i n thi s report . 

The two-hour desiccato r and Perforato r tes t result s shown i n 

Table I I are als o indicativ e of very low formaldehyde level s fo r 

phenoli c panels. As with most of the result s obtained i n dynamic 

chamber tests , the uniformit y of these tes t results , both withi n and 

between studies , indicate s that the variou s phenoli c panel products 

a re quit e simila r with respec t to thei r emittin g potential . 

Twenty-four hour desiccato r test s were als o conducted i n some of 

the studie s summarized i n Tables I and I I (8,10), but the result s are 

not shown sinc e differen t tes t procedures were used i n each of the 

studie s and the data are, therefore , not comparable. 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
32 FORMALDEHYD E RELEAS E FRO M WOO D PRODUCT S 

In additio n to the studie s summarized i n Tables I and II , Meyer 

(13) measured formaldehyde emissions from samples of phenoli c ply -

wood, waferboard and particleboar d using a modifie d versio n of the 

Japanese Industria l Standard, which i s a type of 24-hour desiccato r 

test . Emissions from wood veneer and a urea formaldehyde-bonded 

particleboar d with known emission characteristic s were als o measured. 

Thi s researche r used the desiccato r tes t results , along with informatio n from the literature , to estimate the maximum amount of formaldehyde that might potentiall y be contribute d by phenoli c panel products 

to indoor air . Assuming a loadin g facto r of 1.18-m^/m3 and rio ventilation , calculation s showed that phenoli c panels would contribut e 

les s than 0.05 ppm. Assuming a ventilatio n rat e of one-half ai r 

change per hour, calculate d level s were below 0.0025 ppm. The test s 

als o indicate d that formaldehyde level s associate d with wood veneer 

alone (without any added adhesive) were about the same as level s associate d with phenoli c panels. No background formaldehyde level s 

were reported , however; and considerin g the finding s of studie s which 

a re discusse d later , background level s could easil y have been as high 

as those reporte d fo r both the veneer and the phenoli c products. 

Regardless of background leve l considerations , the study generall y 

indicate s that phenoli c panels emit extremely low level s of formaldehyde, thus corroboratin g the finding s of the studie s discusse d 

earlier . 

Sundin (14) als o measured formaldehyde emissions from a sample 

of phenoli c plywood i n a stati c chamber (no ai r exchange) with a 

volume of 15 m3. The temperature was maintained at 20°C and the 

loadin g rat e was 1 m^/m3. Relativ e humidity was not controlled , but 

was reported to be generall y i n the range of 30-50%. The exact formaldehyde leve l measured i n the chamber was not reported , but the 

author concluded that ... "the emission from phenol formaldehyde (PF) 

- glued plywood i s extremely low and i n practic e i s negligibl e ... " 

A graph i s presented that indicate s the leve l was below 0.2 ppm. As 

indicate d i n Table II , a Perforato r value of 0.6 mg/lOOg was als o 

reporte d fo r thi s plywood. 

Roffae l (15) measured formaldehyde emissions from a phenoli c 

particleboar d using the "WKI-Method" which involve s suspending small 

samples over 50 cm3 of distille d water i n tightl y close d polyethylen e 

bottle s and measuring formaldehyde level s i n the water afte r varyin g 

times. Temperatures were maintained at 42°C. This work indicate d 

that formaldehyde releas e from the phenoli c particleboard s ceased 

afte r a relativel y short reactio n perio d (approximately 96 hours) . 

Thi s findin g i s consisten t with the resi n stabilit y consideration s 

discusse d previousl y under theoretica l considerations . 

Previousl y Unpublished Information 

Much of the informatio n pertainin g to formaldehyde emissions from 

phenoli c panels has been obtained by manufacturers of these products 

but has not been publishe d previousl y i n the open literature . This 

informatio n has been obtained primaril y to form a basi s fo r answering 

consumer inquiries . 

American Plywood Associatio n Study. Probably the most extensive 

study of phenoli c panel emissions was conducted by W. F. Lehmann of 

Weyerhaeuser Company fo r the American Plywood Association . In thi s 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
3. EMER Y Wood Panel Products Bonded with Phenol Formaldehyde Adhesives 33 

investigation , formaldehyde emissions from representativ e samples of 

a l l major types of phenoli c panels were measured using a Large-Scale 

Dynamic Chamber (LSDC) and two-hour desiccato r tests . 

Panel types include d southern pine and Douglas-fi r plywood, 

oriente d strand board from two differen t manufacturers, waferboard, 

and a phenoli c particleboard . For each product type, fiv e 1.2m x 

2.4m (4 f t x 8 ft ) panels were obtained during a singl e shift . The 

panels were kept stacked together during shippin g and storage unti l 

three days prio r to teting , when they were placed i n racks i n order 

to allow ai r circulatio n around each panel. 

Strip s measuring 15.2 cm i n width were cut from the centers of 

four of the fiv e panels, paralle l to the shorte r panel dimension. 

Four 2-hour dessicato r tes t specimens, each measuring 7 cm x 12.7 cm 

(2-3/4 in . x 5 in.) , were cut from each stri p and conditione d overnight . Two desiccato r test s were conducted fo r each product type, 

with each desiccato r containin g eigh t specimens. Tests were performed i n accordance with standard procedure FTM 1 (16). 

Specimens fo r the LSDC test s were prepared from the leftove r 

portion s of the four panels which were cut fo r desiccato r tes t speci -

mens and als o from the fift h panel sampled fo r each product type. 

Most of the products were teste d relativel y soon afte r 

manufacture and again afte r they were aire d out fo r 3 or more months 

by placin g them on sticker s to allow ai r circulatio n between indi -

vidua l panels. The time allowed fo r airin g i s to be distinguishe d 

from panel age or ageing, sinc e formaldehyde level s tend to remain 

constant fo r panels which are stacked tightl y together; whereas, 

level s decrease quit e rapidl y during airin g out (10) . Thus, airin g 

time i s more critica l than actua l panel age when considerin g formaldehyde emissions. Since the panels fo r each of the products studie d 

were kept stacked together unti l they were conditione d fo r the 

initia l testing , al l products were relativel y "fresh" , i n one sense, 

regardles s of the time which had elapsed sinc e thei r manufacture. 

In the dynamic chamber tests , the larg e chamber (55.4 m3 ) was 

loaded at a rat e of 0.43 m^/m3, and the ventilatio n rat e was maintaine d at 0.5 ai r changes per hour. The tes t temperature was 25 _+ 

1°C, and the relativ e humidity was hel d at 50 _+ 5%. Ai r sampling 

was accomplished with three sets of double impingers at one lite r 

per minute fo r 60 minutes, twice per day fo r two days. Formaldehyde 

was analyzed usin g the acetylaceton e procedure (10). 

The result s of the study are summarized i n Table II I which 

provides 2-hour desiccato r values and dynamic chamber values fo r 

both fres h and aire d out panels. For most of the product types, 

both empty chamber and loaded chamber formaldehyde values are provided , the empty chamber values representin g "background" measurements taken jus t before the chamber was loaded. These background 

level s represent residua l formaldehyde present i n the chamber from 

previous testing . 

The data indicat e that the loaded chamber values were below 

0.1 ppm fo r al l products and, also , that the background level s (i n 

the empty chamber) were on the same order of magnitude as the level s 

observed with panels present. In fact , the data show that the background level s i n some cases were as high as the level s measured when 

the chamber was full y loaded, especiall y afte r the panels had been 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
Table III . Summary of Formaldehyde Test Data fo r Various Phenolic

2 Hour Initia l Test 

Large-Scale Dyna

Products^

1 ) 

Desiccato r 

Jug/ml)(2) 

Panel Age 

(Days) 

W/Panels 

(ppm)(4) 

Empty 

(ppm)t4) 

St

Tim

SPP, 13 mm, 

0.04(5) 4-ply 0.08 32 0.04(5) 0.01 

DFP, 14 mm, 

5-ply 0.18 1 0.05 0.01 

OSB No. 1, 

12 mm 0.14 19 0.07 0.01 

OSB No. 2, 

(Sample 1), 12 mm 0.02 21 0.07 0.07 

OSB No. 2, 

(Sample 2), 12 mm 0.09 21 0.03 — 

WB (Sample 1), 

12 mm 0.17 55 0.08 0.03 

WB (Sample 2), 

12 mm 0.03 21 0.06 0.03 

PB, 19 mm, 

hot-melt coatin g 0.15 16 0.08 — 

(1) SPP = southern pine plywood; DFP = Douglas-fi r plywood; OSB = oriente d st

PB = particleboard . 

(2) Micrograms of formaldehyde per ml distille d water. In thi s test , 25 ml d

dis h i s placed i n a desiccato r with eigh t 7 cm x 12.7 cm specimens fo r 2 

analyzed fo r formaldehyde (16). 

(3) Test conditions : 25 +_ 1°C, 50 +_ 5% RH, 0.5 ai r changes per hour, 0.43 m^

area/volume). 

(4) Amount of formaldehyde, part s per millio n part s of ai r i n the tes t chambe

(5) The sample was reteste d at 0 ai r changes per hour, and formaldehyde conce

0.06 ppm. 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch00

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
3. EMER Y Wood Panel Products Bonded with Phenol Formaldehyde Adhesives 35 

aired . Because of the complex equilibri a involved , i t i s not 

possibl e to simply correc t the panel tes t data fo r background levels . 

Therefore , i t i s not feasibl e to use the result s to deriv e an exact 

emission value fo r any of the products or to compare the variou s pane l products. Instead, i t i s probably most prudent to simply conclude 

from thi s study that the upper limi t on emissions from al l types of 

phenoli c panels, as determined i n the larg e tes t chamber, i s les s 

than 0. 1 ppm. 

Although the high level s of "noise " due to background formaldehyde level s preclude meaningful statistica l comparisons between 

emissions fo r variou s product types, certai n other comparisons can 

be made. For example, a statistica l t-tes t involvin g appropriatel y 

paire d observations indicate s a significan t differenc e at the 1% 

confidence leve l between loaded and empty chamber values fo r the 

fres h panels. Thi s differenc e indicate s that the panels were probabl y contributin g some formaldehyde to the tes t chamber, although i t 

i s not possibl e to determine how much, due to the complex equilibri a 

involved . A simila r analysi s of the differenc e between loaded and 

empty chamber values fo r aire d panels, however, shows a barel y sig -

nifican t t-value at the 5 percent confidence level . Thus, the aire d 

panels were probably contributin g very little , i f any, formaldehyde 

to the ambient atmosphere i n the chamber. Evidently , the small 

amount of formaldehyde present initiall y i n phenoli c panels dissi -

pates as the panels ai r out, so that loaded chamber level s approach 

background levels . 

I f background level s are ignored, a t-tes t involvin g paire d 

observation s representin g those 5 set s of panels that were teste d 

both before and afte r the panels were aire d indicate s that fres h 

panels emit more formaldehyde than aire d panels (5% confidence 

level) . Although such a statistica l comparison i s tenuous because 

of the confounding effect s of the background levels , i t i s supported 

by the conclusion s drawn above — i.e. , that fres h panels were apparentl y increasin g the level s of formaldehyde i n the chamber to a sig -

nifican t degree, while aire d panels were contributin g very little , i f 

any, formaldehyde to the chamber. 

The two-hour desiccato r values shown i n Table II I are simila r to 

those associate d with the studie s cite d earlie r i n thi s report , and 

they are als o indicativ e of extremely low formaldehyde emissions from 

the panels. 

Other Unpublished Data. Table IV summarizes additiona l emission 

data which have been supplie d to the American Plywood Associatio n by 

variou s phenoli c panel manufacturers. Data from both large-scal e 

dynamic chamber test s and 2-hour desiccato r test s are provided. Thi s 

informatio n agrees with that provided i n the study describe d above 

and again demonstrates that formaldehyde emissions from phenoli c 

panels are extremely low. In fact , fo r most of the products, the 

chamber background level s were as high as the level s during testing , 

suggesting that the products probably were not even contributin g any 

formaldehyde to the chamber environment. These data again demonstrat e that phenoli c panels are such weak emitter s that background 

formaldehyde level s can easil y interfer e with testing . 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
Table IV. Result s of Large-Scale Dynamic Chamber Tests and Two-

on Various Types of Phenoli c Panel Products ( 

Company 

Code 

Product 

Type<

2 ) 

Panel Age 

at Test 

(Days) 

Dynamic Chamber Test Parameters 

Preconditio n 

Time^

3 ) 

(Days) 

Loadin; 

Rate<

4 

(m^/m

f 

3

) 

Temp. 

(C) 

Rel . 

Humid. 

(%) 

A SPP, 18mm, 4-ply 

A SPP, 16mm, 5-ply 

A SPP, 16mm, 5-ply 

A DFP, 13mm 

B PB, 16mm 

C SPP, 16mm, 5-ply 

C COMPLY, 16mm 

C WB, 16mm 

C WB, 16mm 

D PB, 19mm 

D PB, 19mm 

D PB, 19mm 

E SPP, 12mm 

30 

30 

22 

8 

8 

2-3 

2-3 

2-3 

2-3 

2-3(8) 

7 ( 9 ) 

7(10) 

2 

0.9 5 

0.9 5 

0.9 5 

0.9 5 

0.4 9 

0.4 9 

0.4 3 

0.5 2 

0.5 2 

0.4 3 

0.4 3 

0.4 3 

0.4 3 

23 

23 

23 

23 

24 

24 

24 

24 

24 

24 

24 

24 

25 

0.5 

0.5 

0.5 

0.5 

1 

1 

1 

1 

1 

1 

1 

1 

1 

48 

48 

48 

48 

50 

50 

50 

50 

50 

45 

42 

42 

42 

1 

1 

1 

1 

1 

5 

5 

5 

5 

55 

48 

50 

56 

0

0

0

0

0.

0.

0.

0.

(1) Ventilatio n rat e was 0.5 ai r changes per hour fo r al l tests . Chromotrop

f o r HCHO analyses , unless noted otherwise. Differen t tes t chambers were 

companies represented . 

(2) SPP = southern pine plywood; DFP = Douglas-fi r plywood; PB = particleboa

(3) Specimens were preconditione d at the same temperature and relativ e humid

chamber. 

(4) Loading i s give n i n terms of square meters of panel surfac e per cubic me

chamber. 

(5) Al l desiccato r test s were performed i n accordance with the procedures gi

FTM 1-1983 (16) with edges unsealed unles s noted otherwise. Values repr

per ml distille d water. In thi s tes t 25 ml distille d water i n a petr i d

with eigh t 7 cm x 12.7 cm specimens fo r 2 hours, and the water i s then a

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch00

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
Table IV. (continued) 

(6) Pararosanilin e was used fo r formaldehyde analysis , rathe r than chromotr

specimens as those used i n the tes t whose result s are reported directl y 

(7) Range typicall y encountered at thi s tes t facility . 

(8) Background formaldehyde leve l i n conditionin g area was 0.08 ppm. 

(9) Background formaldehyde leve l i n conditionin g area was 0.03 ppm. 

(10) Background formaldehyde leve l i n conditionin g area was 0.05 ppm. 

(11) Average of four test s involvin g samples from two separate panels: fo r e

had seale d edges, while those fo r the other test s were unsealed. Range 

(12) Average of four measurements made on four consecutiv e days. Range was 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch00

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
38 FORMALDEHYDE RELEASE FROM WOOD PRODUCTS 

Summary and Conclusions 

All the available information indicates that formaldehyde levels 

associated with wood panel products bonded with phenol formaldehyde 

adhesives are extremely low. Data resulting from laboratory studies 

involving large-scale dynamic test chambers consistently indicate 

that levels are below 0.1 ppm under conditions simulating those 

which might be found in tightly sealed homes containing freshlymanufactured panels. In fact, test chamber levels are generally 

about the same as the annual average formaldehyde concentrations 

which have been reported for outdoor air in many cities (17). Moreover, the data, as well as theoretical considerations, indicate that 

the amount of formaldehyde contributed to the environment by phenolic 

panel products should rapidly approach zero as the small amount of 

formaldehyde initially present in the panels is released. 

Literature Cited 

1. Blomquist, R. F. "Formaldehyde Emissions Are No Problem With 

Wood Products Bonded With Phenolic Resins"; American Plywood 

Association: Tacoma, WA, 1981. 

2. Troughton, G. E. Wood Science 1969, 1, 172-6. 

3. "Formaldehyde; Determination of Significant Risk; Advance 

Notice of Proposed Rulemaking and Notice," Fed. Register, 

1984, 49, 21820-98. 

4. Nestler, F. H. Max. "The Formaldehyde Problem in Wood-Based 

Products -- An Annotated Bibliography"; U. S. Dept. 

Agriculture: Forest Products Laboratory, Report FPL-8, 1977. 

5. Berg, A.; Mellegard, B.; Hanetho, P.; Ormstad, E. B. Holz als 

Roh-und Werkstoff 1980, 38, 251-5. 

6. Couch, B. "Formaldehyde Study -- Testing of Plywood Panels"; 

Weyerhaeuser Company: Tacoma, WA, Report 0452-102 IN, 1981. 

7. Myers, G. E. For. Prod. J. 1985, 35, 20-31. 

8. Myers, G. E.; Nagaoka, M. Wood Science 1981, 13, 140-50. 

9. "Large-Scale Test Method For Determining Formaldehyde Emissions 

From Wood Products -- Large Chamber Method, FTM 2-1983"; 

National Particleboard Association: Gaithersburg, MD, 1983. 

10. Myers, G. E. For. Prod. J. 1983, 33, 27-37. 

11. Myers, G. E. For. Prod. J. 1984, 34, 59-68. 

12. "Formaldehyde Emission Comparison"; Champion International 

Corp.: Stamford, Conn., 1983. 

13. Meyer, B. "Formaldehyde Release From Phenolic Bonded Wood 

Panels"; American Plywood Association: Tacoma, WA, 1981. 

14. Sundin, B. Proc. 12th Wash. State Univ. International Sympos. 

on Particleboard, 1978, p.251. 

15. Roffael E. Proc. 12th Wash. State Univ. International Sympos. 

on Particleboard, 1978, p.233. 

16. "Small Scale Test Method For Determining Formaldehyde Emissions 

From Wood Products -- Two Hour Desiccator Test, FTM1-1983"; 

National Particleboard Association: Gaithersburg, MD, 1983. 

17. "Indoor Pollutants," National Research Council, National 

Academy Press: Washington, D.C., 1983, p. 93. 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986. 
3. EMERY Wood Panel Products Bonded with Phenol Formaldehyde Adhesi

18. Matthews, T. G.; Hawthorne, A. R.; Daffron, C. R.; Reed, T. J.; 

Corey, M. D. Proc. 17th Wash. State Univ. International 

Particleboard/Composite Materials Sympos., 1983, p. 179. 

19. Matthews, T. G.; Hawthorne, A. R.; Daffron, C. R.; Reed, T. J. 

Proc. Air Pollution Control Assoc. Specialty Conf. on Meas. and 

Monitoring of Noncriteria Toxic Contaminants, 1983, p. 150. 

20. "Formaldehyde Emission Survey of the Waferboard Association"; 

National Particleboard Association: Gaithersburg, MD, 1984. 

21. Roffael, E.; Mehlhorn, L. Holz als Roh-und Werkstoff 1980, 

38, 85-8. 

RECEIVED January 14, 1986 

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 Publication Date: August 8, 1986 | doi: 10.1021/bk-1986-0316.ch003

In Formaldehyde Release from Wood Products; Meyer, B., et al.; 

ACS Symposium Series; American Chemical Society: Washington, DC, 1986.