Tiêu chuẩn iso 12460 4 2016

© ISO 2016 Wood based panels — Determination of formaldehyde release — Part 4 Desiccator method Panneaux à base de bois — Détermination du dégagement de formaldéhyde — Partie 4 Méthode au dessiccateur[.]

Wood-based panels — Determination

Part 4:

Pa nea x à b se de b is — Déte mination du dé a ement de

frmaldé yde —

Partie 4 : Méth de a de ssiccateur

S con edition

2 16-0 -1

Refer ence n mb r

ISO 1 4 0-4:2 16(E)

COPYRIGHT PROTECTED DOCUMENT

© ISO 2016, P blshed in Sw itz rlan

A ll rig hts r eserved Unles otherw ise spe ified, nopar of this p blc tion ma y be r epr od c d or utilz d otherw ise in an form

or b an me ns, ele tr onic or me hanic l, inclu in p oto opying , or postin on the internet or an intranet , w ithout prior

written permis ion Permis ion c n be req esed from either ISO at the ad r es below or ISO’s member bod y in the c u try of

the r eq eser

ISO c pyrig ht ofic

C de Blan on et 8 • C 4 1

CH-1 14 Vernier, Geneva, Sw itzerlan

F reword i v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Principle 1

4 Re g ents 1

5 A pparatus 2

6 Test piec es 2

6.1 Sampl ng 2

6.2 Dimensions 4

6.3 Numbe of tes pie es 4

6.4 Numbe of emis ion tes s 4

6.5 Conditioning 4

7 Proc ed re .4

7.1 Desic ator prep r ation 4

7.1.1 New desic ators 4

7.1.2 Befor e each dete mination 4

7.2 Tes con itions 5

7.3 Positioning of the tes pie es 5

7.4 Monitoring of tes con itions 5

7.4.1 Temperatur e 5

7.4.2 Backg rou d formaldehyde 5

7.5 Tes d ration 5

7.6 Sample cole tion 5

8 Deter minatio of for maldeh yde 5

8.1 General 5

8.2 Principle 5

8.3 Pr oc dure 6

8.4 Calbration curve 6

8.4.1 General 6

8.4.2 Formaldehyde stan ar d solution 6

8.4.3 Formaldehyde calbration solution 6

8.4.4 Dete mination of the calbration curve 7

8.5 Calculation of the conc ntration of formaldehyde in the glas c ystal zing dish in the desic ator 7

9 Ex pres io of results 7

10 Test rep rt 7

Biblog raphy 9

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a lshed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www.iso.org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sp nsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www.iso.org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the meaning of ISO spe ific t erms an ex r s ions r lat ed t o conformity

as es ment, as wel as information a out ISO’ s adhe enc t o the WTO principles in the Te h ical

Bar ie s t o Trade (TBT) se the fol owing URL: F or word - Sup lementary information

The committ ee r sp nsible for thisdocument is ISO/TC8 , Wo d-b s ed p nels

This se on edition canc ls an r plac s the firs edition (ISO 1 460-4:2 0 ), w hich has be n

t ech icaly r vised with the folowing chang es:

a) introd ction wasdelet ed;

b) r fe enc t o JANS 1 was delet ed in the sco e;

c) pro isions for low emit ing b ards we e ad ed in 5.6

It also incorporat esthe Amen ment ISO 1 46 -4:2 08 /Amd 1:2 1

ISO 1 46 consis s of the folowing part , u de the g ene al title Wo d-b s ed p nels — Determin tio o

frmaldeh de r lease:

— Part 1: Formaldeh de emi s s io b the 1-c ubic-metr chambe meth d

— Part 3: G as a alys i s meth d

— Part 4: Des icc ator meth d

— Part 5: Ex trac tio meth d (c aled the pe frator meth d)

Wood-based panels — Determination offormaldehyde

Part 4:

This part of ISO 1 46 spe if ies a desic at or method for the det ermination of the q antity of

formaldehyde emitt ed from p rticlebo rd, fibr b ard, plywo d, orient ed s rand bo rd (OSB) an

wo den laminat ed flo ring

2 Normati ve r eferences

The folowing document , in w hole or in p rt, ar normatively r fe enc d in this document an ar

in ispensa le for it a pl cation F or dat ed r fe enc s, only the edition cit ed a pl es F or u dat ed

r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment )a pl es

ISO 1 9 9, Wo d-b s ed p nel s — S mpln a d c ut in o tes t piec es

Emis ion of formaldehyde is det ermined b placing t es pie es of k own surfac ar a in a desic at or at

a controled t empe atur an measuring the q antity of emitt ed formaldehyde a sorbed in a spe ified

v lume of wat er d ring 24 h

4 Reag ents

Use only r ag ent of r co niz d analytical grade, unles othe wise spe if ied, an dis i led or

demine al z d wat er or wat er of eq iv lent purity

4.1 Ac etylac etone-ammonium ac etate solution

Dis olve 1 0 g ammonium ac tat e (C

2 H

3 O

2 NH

4 ) in 8 0 ml wat er in a 1 0 0 ml one-mark v lumetric

flask (5 9) A dd 3 ml glacial ac tic acid (C

2 H

4 O

2 ) an 2 ml ac ty lac t one (pentane- 2,4-dione, C

5 H

8 O

2 )

an mix thoroughly int o the solution Make up t o the mark with wat er During st orag e, prot ect the

solution from lght Discard the solution 3 day s aft er pr paration

4.2 Io ine standar d solution, c(l

2 ) = 0,0 mol/l

Stan ardiz the solution befor use

4.3 Sodium thiosulfate standard solution, c (Na

2 S

2 O

3 )= 0,1 mol/l

Stan ardiz the solution befor use

4.4 Sodium h ydrox ide stan ard solutio , c(NaOH)= 1 mol/l

Stan ardiz the solution befor use

4.5 Sulfuric acid standar d solutio , c (H

2 SO

4 ) = 1 mol/l

Stan ardiz the solution befor use

4.6 Star ch solutio , 1 % mas fraction

The usual la orat ory a p ratus an , in particular, the folowing:

5.1 Glas desic cator s, with an enclosed v lume of (1 ± 2) l ca a le of enclosing a sup ort (5.2)

5.2 Wire g r id or su por t, of diamete (240 ± 1 ) mm of s ainles s e l wir e such that the dis anc

betwe n par alel pie es of wir e is not les than 1 mm ( e Fig ur e 1)

5.3 Glas c ystal izing dish, circular of inside diamete (1 5 ± 1) mm an depth (6 ± 2) mm

5.4 S mple holder , of s ainles s e l wire, to hold the tes pie es upr ight in the desic ator ( e Figure 2)

5.5 Temper atur e-me suring dev ice, e.g a the mocouple, ca a le of measuring temper atur e w ith

an e r or lmit of ± ,1 °C, plac d inside a desic ator (5.1) located adjac nt o the desic ator( )containing

the tes pie es

5.6 Spectrophotometer, ca a le of measuring a sor banc at 41 nm The use of c ls of p thleng th at

leas 5 mm is r ecommen ed and is r eq ir ed for low emitting b ar ds Fluor ometric dete mination can

also be used to gain mor e sensitivity

5.7 Water bath, ca a le of maintaining a temperatur e of (6 ± 2) °C

5.8 Volumetr ic flasks, six , of ca acity 1 0ml

5.9 Volumetr ic flasks, two, of ca acity 1 0 0ml

5.10 Bulb pipetes, of ca acities 5 ml, 1 ml, 15 ml, 2 ml, 2 ml, 50 ml, an 1 0 ml or suita le auto

pipete

5.11 Microburet e or auto dispenser

5.12 Flasks with stopper s, of ca acity 1 0 ml

5.13 Balanc e, ca a le of measuring to 0,00 g

6 Test piec es

Samplng an cut ing of the t es pie es shal be car ied out in ac ordanc with ISO 1 99

Dimensions in milimetre

Figure 1 — Stainles steel wire grid for sup orting the test pieces in the desic ator

Key

1 su porting metal

2 test pieces

Figure 2— E ample of wire sample h lde to hold the test pieces in the desic ator

6.2 Dimensions

The t es pie es, of thick es , δ, in mi lmetr s, shal be of length (1 0 ± 1,0) mm an of width

(5 ± 1,0)mm

6.3 Number of test piec es

The n mbe of t es pie es shal be det ermined b their t otal surfac ar a The sum of the ar as of the

en s, sides an fac s shal be as closeas pos ible t o 18 0 cm

2

6.4 Number of emis ion tests

The emis ion t es s shal be car ied out in d pl cat e

NOTE For int ernal routine control, a single emis ion test might b suff icient

The dife enc s betwe n emis ions of the two t es s shal be within 2 % of their arithmetic a e ag e,

othe wise a third emis ion t es shal be car ied out

6.5 Conditioning

Con ition the t es pie es for 7 day s or t o cons ant mas in an atmosphe e with a mean r lative h midity

of (6 ± 5) % an a t empe atur of (2 ± 2) °C

C ns ant mas is conside ed to ha e be n r ached when the r sult oftwo suc es ive weighing o e ations,

car ied out at an int erv al of 24 h, do not dife b mor than 0,1 % of the mas ofthe tes pie e

The t es pie es t o be con itioned shal be sep rat ed b at leas 2 mm an p sitioned so that air can

cir ulat e fr ely o e al surfac s

Tes pie es containing low levelsof formaldehyde wi a sorb formaldehyde from the atmosphe e w hen

b ckgrou d levels of formaldehyde ar high C r should be taken t o a oid such con itions d ring

st orag e an con itioning b use of a formaldehyde r mo al sy st em or b maintaining low v lumes of

t es pie es in the ro m The b ckgrou d level is measur d b ex osing a glas c y stal zing dish (5.3)

containing 3 0 ml wat er t o the con itioning atmosphe e for 24 h, an analy sing the r sulting solution

The ma imum b ckgroun level shal be les than thenominal emis ion level of the t es pie es (e.g for

t es pie es from a sample with ex e t ed emis ions of 0,3 mg l, the b ckgroun levels should be les

than 0,3 mg l)

7 Proc edure

7.1 Desic cator pr eparation

7.1.1 New desic cator

Thoroughly clean new desic at ors an those pr viously used for purp ses othe than the det ermination

of formaldehyde

7.1.2 Before e ch deter minatio

Rinse thedesic at or (5.1) an the glas dish (5.3) with wat er an dry them befor each det ermination

Plac (3 0 ± 1) ml of wat er at (2 ± 1) °C in the glas dish (5.3), an locat e it c ntraly at he b tt om of

the desic at or Position the wir mesh sup ort (5.2) a o e the glas dish within the desic at or

7.2 Test c onditions

Plac the desic at or on a vibration-fr e surfac in an environment ca a le of maintaining the air

t empe atur inside the desic at or at (2 ± 0,5)°C

7.3 P ositioning of the test piec es

Inse t the t es pie es, fr e of any lo se p rticles, int o the wir sample holde (5.4) befor placing it

inside the desic at or Position the sample holde containing the t es pie es inside the desic at or at the

c ntr of the wir mesh sup ort so that it is locat ed dir ctly a o e the glas dish

7.4 Monitor ing of test c onditions

7.4.1 Temperatur e

Pr p r a control desic at or (5.1) as spe if ied in 7.1.2 but containing no t es pie es, an f it it with a

t empe atur -measuring devic (5.5) Monit or the t empe atur inside the desic at or contin ously, or at

int erv ls not ex ce ding 1 min, an r cord the mean t empe atur d ring the t es pe iod

Alt ernatively, the t empe atur ma be monit or d b locating the t empe atur -measuring devic (5.5)

in the t es environment adjac nt t o the desic at or

7.4.2 Backg r ound for maldeh yde

Measur the b ckgrou d formaldehyde in the t es ing environment using the control desic at or (7.4.1)

The ma imum ac ept ed b ckgrou d level is0,0 mg l

7.5 Test duration

The d ration of the t es shal be 24 h ± 1 min

7.6 S mple c ol ection

Thoroughly mix the formaldehyde solution contained in the glas dish Rinse a 1 0 ml one-mark

v lumetric flask (5.8) with the formaldehyde solution and then f il it t o the mark with the solution Use

a glas st op e t o seal the flask If the sample is not t o be analy sed immediat ely, st or it betwe n 0 °C

an 5°C for a ma imum of 3 h

F olow thesame proc d r for the measur ment of b ckgroun formaldehyde

8 Determination of formaldehyde

Det ermine the formaldehyde cont ent of the aq eous solutions phot ometrical y b the ac ty lac t one

method

8.2 Principle

The det ermination is based on the Hantzsch r action in w hich the formaldehyde r act with ammonium

ions an ac ty lac t one t o yield diac ty ldihydrot oluidine (DDL) DDL has an a sorption ma imum at

41 nm The r action is spe ific t o formaldehyde( e R efe enc [1])

8.3 Proc edure

Pipett e (5.1 )2 ml of the formaldehyde solution t o beanaly sed int o a 1 0 ml flask (5.1 ), ad 2 ml of

the ac ty lac t one-ammonium ac tat e solution (4.1) an seal the flask with a st op e

Heat the st op e ed flask for 1 min in a wat er b th (5.7) at (65 ± 2) °C Then st or the solution at 2 °C

for (6 ± 5) min, prot ect ed from lght, befor det ermining the a sorb nc of the solution at a wa elength

of 41 nm a ains wat er, using a spe tro hot omet er (5.6) Det ermine b ckgroun formaldehyde (7.4.2)

using the same proc d r

If ma imum a sorb nc oc urs at a wa elength othe than 41 nm, al measur ment , inclu ing

calbration, ma be con uct ed at this wa elength

8.4 Cal bration cur ve

8.4.1 General

The calbration curve is prod c d from a s an ard formaldehyde solution, the conc ntration of w hich

has be n det ermined b iodometric titration Che k the calbration curve at leas onc a month It is

det ermined using the method in 8.4.2 or a suita le eq iv lent

If monthly calbration show les than 2% v riation on the mean v lues, the cal bration curve che king

int erv l ma beinc eased R ecords should be kept t o jus ify any inc eased che king int erv l

8.4.2 F r maldeh yde standard solutio

Diut e a out 1 ml formaldehyde solution (mas fraction 3 % t o 40 % ) in a 1 00 ml volumetric flask

(5 9) with wat er, an make up t o the mark with wat er

To det ermine the ex ct formaldehyde conc ntration of this solution, mix a 2 ml v lume with 2 ml

iodine solution (4.2) an 1 ml sodium hydro ide solution (4.4) Alow t o s an for 1 min, prot ect ed

from lght, then ad 1 ml of sulfuric acid solution (4.5) Back-titrat e the surplus iodine with the sodium

thiosulfat e solution (4.3) Near the en of the titration, ad a few dro s of s ar h solution (4.6) as

in icat or Pe form a blank t es on 2 ml wat er in p ralel

The formaldehyde cont ent, as a conc ntration in mi lgrams pe ltr , ρ(HCHO), is calculat ed from

F ormula (1):

ρ(HCHO)=(V −V)× ×c(Na S O )× /

w he e

c (Na

2

S

2

O

3

) is the thiosulfat e solution (4.3) conc ntration, in moles pe ltr ;

V is the v lume, in mi l itr s, of thiosulfat e solution (4.3) consumed in the t es titration;

V

0

is the v lume, in mi l itr s, of thiosulfat e solution (4.3) consumed in the blank

titra-tion

NOTE 1 ml 0,1 mol/l thiosulfate solution (4.3) cor espon s t o 1 ml 0,0 mol/l iodine solution (4.2) an

1,5 mg formaldehyde

8.4.3 F r maldeh yde calbratio solutio

Using the conc ntration v lue det ermined in 8.4.2, calculat e the volume w hich wi l contain 3 mg

formaldehyde Trans e this volume, using a mic o ur tt e (5.1 ), t o a 1 0 0 ml v lumetric flask (5 9)