DEAS 326: 202 3 
ICS 77.100.50  
 
© EAC 2023                                                                                                                         Second Edition 2023  
 DRAFT EAST AFRICAN STANDARD  
Copper/chromium/arsenic composition for the preservation of timber — 
Specification  
EAST AFRICAN COMMUNITY  
 DEAS 326: 2023 
ii © EAC 202 3 – All rights  reserved  
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© EAC 2023 – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Composition  ................................ ................................ ................................ ................................ ...........  2 
4.1 Raw materials  ................................ ................................ ................................ ................................ ........  2 
4.2 Formulation  ................................ ................................ ................................ ................................ ............  2 
5 pH value of solution  ................................ ................................ ................................ ..............................  3 
6 Insoluble matter  ................................ ................................ ................................ ................................ ..... 3 
7 Sampling and analysis  ................................ ................................ ................................ ..........................  3 
7.1 Sampling  ................................ ................................ ................................ ................................ ................  3 
7.2 Analysis  ................................ ................................ ................................ ................................ ..................  3 
Annex  A (normative)  Determination of pH  ................................ ................................ ................................ ...... 4 
A.1 Apparatus  ................................ ................................ ................................ ................................ ...............  4 
A.2 Reagent  ................................ ................................ ................................ ................................ ..................  4 
A.3 Preparation of test solution  ................................ ................................ ................................ ..................  4 
A.4 Determination  ................................ ................................ ................................ ................................ ........  4 
Annex  B (normative)  Determination of insoluble matter  ................................ ................................ ...............  5 
B.1 Apparatus  ................................ ................................ ................................ ................................ ...............  5 
B.2 Preparation of test portion  ................................ ................................ ................................ ...................  5 
B.3 Determination  ................................ ................................ ................................ ................................ ........  5 
B.4 Calculation  ................................ ................................ ................................ ................................ .............  5 
Annex  C (normative)  Method fo r determination of preservative penetration  ................................ .............  6 
C.1 Test Specimens  ................................ ................................ ................................ ................................ ..... 6 
C.2 Measurement of penetration  ................................ ................................ ................................ ................  6 
C.2.1  Oil Preservatives  ................................ ................................ ................................ ................................ ... 6 
C.2.2  Waterborne Preservatives  ................................ ................................ ................................ ....................  6 
C.3 Measurement of Penetration  ................................ ................................ ................................ ................  6 
Oil preservatives  ................................ ................................ ................................ ................................ .................  6 
C.4 Copper  ................................ ................................ ................................ ................................ ....................  6 
C.4.1  Chrome Azurols Test  ................................ ................................ ................................ ............................  6 
C.4.2  Rubeanic Acid Test  ................................ ................................ ................................ ...............................  7 
C.5 Arsenic  ................................ ................................ ................................ ................................ ...................  7 
C.6 Pentachlorophenol in o il solution  ................................ ................................ ................................ ....... 7 
Cuprin Acetate Test  ................................ ................................ ................................ ................................ ............  7 
Bibliography  ................................ ................................ ................................ ................................ ........................  8 
 DEAS 326: 2023 
iv © EAC 202 3 – All rights  reserved  
 Foreword  
Development of the East African Sta ndards has been necessitated by the need for harmonizing requirements 
governing quality of products and services in the East African Community. It is envisaged that through 
harmonized standardization, trade barriers that are encountered when goods and serv ices are exchanged 
within the Community will be removed.  
The Community has established an East African Standards Committee  (EASC)  mandated to develop and 
issue East African Standards  (EAS) . The Committee is composed of representatives of the National 
Standards Bodies in Partner States, together with the representatives from the public and private sector 
organizations  in the community .  
East African Standards are developed through  Technical Committees that are representative of key 
stakeholders including go vernment, academia, consumer groups, private sector and other interested parties. 
Draft East African Standards are circulated to stakeholders through the National Standards Bodies in the 
Partner States. The comments received are discussed and incorporated before finalization of standards, in 
accordance with the Principles and procedures for development of East African Standards.  
East African Standards are subject to review, to keep pace with technological advances. Users of the East 
African Standards are t herefore expected to ensure that they always have the latest versions of the standards 
they are implementing .  
The committee responsible  for this document is Technical Committee EASC /TC 022, Wood, timber and their 
products . 
Attention is drawn to the possib ility that some of the elements of this document may be subject of patent 
rights. EAC shall not be held responsible for identifying any or all such patent rights.  
This second  edition cancels and replaces the first edition ( EAS 326:2002 ), which has been tec hnically rev ised.  DEAS 326: 202 3 
© EAC 2023 – All rights reserved  v 
 Introduction  
Copper, chromium and arsenic composition is a water borne oxide liquor timber preservative for application to 
timber by vacuum and pressure impregnation.  
The preservative is a finely dispersed oxide liquor of viscosity and s olubility intended to facilitate easy and 
rapid preparation of aqueous treating solutions for preservation of timber against insect attack, termites and 
fungal decay.  
Copper/Chromium/Arsenic (CCA) is hazardous chemical therefore precautions should be taken  through use of 
proper equipment and only by trained personnel. Proper handling and disposal of CCA containers is 
mandatory. This draft East African Standard does not purport to address all of the safety problems associated 
with its use. It is the responsi bility of each partner state to establish appropriate safety and health practices 
and determine the applicability of suitable regulatory limitations prior to utilization.”  
 DRAFT EAST AFRICAN STANDARD  DEAS 326:  2023 
 
© EAC 2023 – All rights reserved  1 
 Copper/chromium/arsenic composition for the preservation of timber — 
Specification   
1 Scope   
This East African Standard specifies requirements for two types of water -borne preservatives containing 
mixtures of compounds of copper ( II), chromium ( VI) and arsenic ( V). 
2 Normative references   
The following documents are referred to in the t ext in such a way that some or all of their content constitutes 
requirements of this document.  For dated references, only the edition cited applies. For undated references, 
the latest edition of the referenced document (including any amendments) applies.  
EAS 123, Water — Distilled quality — Specification  
EAS 124, Rounding off numerical values  
EAS 325, Wood preservatives and treated timber — Guide to sampling and preparation of wood preservative 
and treated timber for analysis  
TZS 660, Wood preservatives and  treated timber — Quantitative analysis for copper/chromium/arsenic 
formulations  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization  at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
timber  
 
3.2  
liquid junction   
any junction between two electrolyte solutions of different composition   
3.3  
sintere d glass filter   
filter produced from porous materials formed by the thermal bonding of particles   
3.4  
pore size index  
characteristic of a filter related to pore diameter  DEAS 326: 2023 
2 © EAC 202 3 – All rights  reserved  
 3.5  
permeability  
characteristic of a filter related to the rate of flow through it u nder specified conditions  
3.6  
test solution  
solution of which the pH value is required  
3.7  
pH meter  
high impedance instrument by means of which either the pH of a solution or the potential difference between a 
pair of electrodes immersed in a solution is  indicated  
3.8  
electrode  
external system that incorporates a fitting solution and a means, such as a ceramic plug or forming the liquid 
junction  
4 Composition  
4.1 Raw materials  
4.1.1  The preservative shall consist essentially of a mixture of compounds of  copper ( II), chromium ( VI) and 
arsenic ( V). 
4.1.2  The mixture of compounds shall be selected to be consistent with this Clause.  
4.1.3  The preferred mixtures of compounds are either : 
a) hydrated copper ( II) sulphate, hydrated sodium or potassium di chromate and  hydrated diarsenic 
pentoxide ; or  
b) copper ( II) oxide, chromium ( VI) oxide and diarsenic pentoxide.  
NOTE  1 Attention is specially drawn to the toxic nature of the formulations and their solutions tha t may be injurious to 
health if adequate precautions are n ot taken. Therefore, particular care and the use of appropriate protective clothing is 
necessary.  
NOTE  2 Currently Type 2 CCA (Oxide Composition) is used in the region . Also special precautions are required for 
disposal of these solutions.  
4.2 Formulation  
4.2.1  The nominal composition of the two types of preservatives (designated Type 1 and Type 2) together  
with minimum concentration of each component shall be as given in Table 1. The sum of the concentrations of 
the individual components shall be not less than 95 % m/m.  
NOTE  Variation in composition from the nominal composition may arise because of variations in the purity of the 
ingredients  and the lack of homogeneity of the mixture.  
4.2.2  The preservatives shall be supplied as mixtures.  
NOTE  The usual for ms are dry ingredients, paste or concentrated solutions.  
4.2.3  Containers shall carry information on the mass of preservatives equ ivalent to unit mass of nominal 
composition.  DEAS 326: 202 3 
© EAC 2023 – All rights reserved  3 
 4.2.4  Preservatives as supplied may differ in composition from the nominal compos ition as a result of  
removal or addition of water. In such cases the ratio of the active ingredients shall be in the same  proportions 
by mass as are the nominal compositions given in Table 1.  
Table 1 — Nominal and minimum proportions of components in formu lations based on metal oxides 
(Oxide Type C composition)  
Elemental Composition   Oxide Composition  
 %(w/w)    %(w/w)  
 Min Nominal  Max   Min Nominal  Max 
Cu 8.05 9.00 9.95  CuO  10.08  11.27  12.46  
Cr 13.70  14.63  15.55   CrO 3 26.35  28.13  29.90  
As 11.60  13.13  14.65   As2O5 17.79  20.13  22.47  
Total  33 37 40  Total  54 60 65 
 
5 pH value of solution  
When tested in accordance with Annex A, the pH value of a solution equivalent to 20g/L of the nominal 
preservative composition shall be neither lower than 1.8 nor highe r than 2.8.  
6 Insoluble matter  
When tested in accordance with Annex B the content of insoluble matter shall not be greater than 0.1 % m/m 
for paste or concentrated solutions, and shall not be greater than 0.25 % m/m for dry powder formulations.  
7 Sampling  and analysis  
7.1 Sampling  
The preservative shall be sampled in accordance with EAS 325.  
7.2 Analysis  
The copper, chromium and arsenic content shall be determined in accordance with TZS 660 on a sample 
prepared in accordance with EAS 325.  DEAS 326: 2023 
4 © EAC 202 3 – All rights  reserved  
 Annex  A 
(normativ e) 
 
Determination of pH   
A.1 Apparatus  
Ordinary laboratory apparatus, together with the following:  
A.1.1  sintered glass filter, suitable for laboratory uses with reasonable pore size index and permeability;  
A.1.2  pH meter, capable of making a measurement with tolerance + 0.2 in a limiting accuracy class and 
fitted with suitable electrodes; and  
A.1.3  one-mark volumetric flask, 500 mL capacity suitable for laboratory use.  
A.2 Reagent  
Water, complying with EAS 123. 
A.3 Preparation of test solution  
Take a mass of the preservative sample equivalent to 10 g + 1.1 g of the nominal composition and weigh it to 
the nearest 0.001g. Transfer this test portion to a beaker and dissolve it in 250 mL of hot water around 40 OC, 
stirring continuously. Cool the solution to room temperature and filter it through the pre -weighed sintered glass 
filter into the one mark volumetric flask. Wash the beaker and the residue on the filter five times with 10 mL 
portions of hot water at app roximately 40 OC, collecting the washings in the flask. Dilute to the mark with 
water. Reserve the filter and residue for the determination of insoluble matter if required (see Annex B).  
A.4 Determination  
Determine the pH of the test solution prepared in a ccordance with (A.3) at 27 OC + 2 OC using the pH meter 
which is intended for determining a pH value within a broad range.  DEAS 326: 202 3 
© EAC 2023 – All rights reserved  5 
 Annex  B 
(normative)  
 
Determination of insoluble matter   
B.1 Apparatus  
B.1.1  Sintere d glass filter, suitable for laboratory uses with reasonable pore size index and permeability.  
B.1.2  Laboratory drying oven, capable of being adjusted to 105 OC + 5 OC. 
B.2 Preparation of test portion  
Weigh a mass of the preservative sample equivalent to 1 0 g + 0.1 g of the nominal composition to the nearest 
0.001 g and dissolve it in water, filter and wash as described in (A.3) or, if the pH has already been 
determined, use the residue on the filter.  
B.3 Determination  
Transfer the sintered filter containin g the residue from (B.2) to the drying oven (B.1.2) previously adjusted to 
105 OC + 5  OC. Dry initially for a period of 1h, cool in a desiccator to room temperature and re -weigh. Repeat 
the drying, cooling and re -weighing operations at suitable intervals u ntil the difference between two 
successive weighings is not greater than 0.5 mg.  
B.4 Calculation  
The percentage by mass of insoluble matter in the preservative m is given by the following equation:  
 
where 
m1 is the mass in g of the sintered glass filter;  
m2 is the mass in g of the sintered filter and residue after drying;  
m3 is the mass in g of preservative taken for the determination.  
 DEAS 326: 2023 
6 © EAC 202 3 – All rights  reserved  
 Annex  C 
(normative)  
 
Method for determination of preservative penetration  
C.1 Test Specimens  
Penetration is best measured  on a freshly prepared end grain surface; alternatively the measurements can be 
taken on increment cores. The end grain surface shall be cut at least 500 mm from the end of the treated 
timber because penetration along the grain is easy and good penetration  is always achieved near the ends of 
preserved timber.  
C.2 Measurement of penetration  
C.2.1 Oil Preservatives  
The depth of penetration is easily seen on the end grain surface.  If the sample has been recently treated, the 
saw or the core bores may smudge t he oil over unpenetrated parts of the timber.  
C.2.2 Waterborne Preservatives  
Sometimes the depth of penetration is not apparent, in which case it is necessary to treat the surface with a 
chemical indicator which changes colour in the presence of surface is  made smooth by planning or 
sandpapering and the chemical indicator applied sparingly, ideally by spray but a rag moistened with the 
chemical indicator is better than wetting the test specimen with indicator.  
C.3 Measurement of Penetration  
Oil preservative s  
The depth of penetration is easily seen on end grain surface. If the sample has been recently treated, the saw 
or the core bores may smudge the oil over unpenetrated parts of the timber.  
Sometimes the depth of penetration is not apparent, in which case it is necessary to treat the surface with a 
chemical indicator which changes colour in the presence of the preservative.  Best results are achieved when 
the end grain surface is made smooth by planning or sandpapering and the chemical indicator applied 
sparingly, ideally by spray but a rag moistened with the chemical indicator is better than wetting the test 
specimen with indicator.  
C.4 Copper  
C.4.1 Chrome Azurols Test  
Reagent:  
A solution containing 0.5 per cent chromo azurol S dye and 5 per cent sodium ace tate in distilled water.  
Application:  DEAS 326: 202 3 
© EAC 2023 – All rights reserved  7 
 Light spray gives a strong royal blue colour in wood with copper, persistent for several weeks. Untreated wood 
becomes orange coloured  
C.4.2 Rubeanic Acid Test  
Reagents:  
A 5 per cent ammonium solution made by diluting 1 part ammonia (0.880) with 6 parts water by volume – 
solution A.  
A 0.5 per rubeanic acid made by dissolving 0.5 g rubeanic acid (dithio -oxamide) in 100 ml ethanol or 
methylated spirit – Solution B . 
Application:  
Spray with solution A followed by solution B produces a royal blue colour in wood containing arsenic.  
C.5 Arsenic  
Reagent:  
Solution A made by mixing 22 ml concentrated hydrochloric acid and 88ml distilled water than dissolving in 
this solution 10g sodium molydbate . 
Solution B made by dissolving 5 g stannous chloride in the mixture of 22ml concentrated hydrochloric acid and 
88ml distilled water. Alternatively, 5 g ascorbic acid is dissolved in 100ml distilled water. The solution does not 
keep long and that last alternative shall be prepared fresh ever y day of test.  
Application:  
Spray with solution A followed after soaking with solution B produces a royal blue colour in wood containing 
arsenic  
C.6 Pentachlorophenol in oil solution  
Cuprin Acetate Test  
Reagent:  
Cupric acetate and 0.5 g wetting agent (s uch as shell ‘Nonident P40’) in 100 ml water.  
Silver nitrate solution made by dissolving 0.4 g silver nitrate in 100 ml water. The solution is light sensitive and 
shall be stored in dark brown glass bottles.  
Application:  
A mixture of equal quantities of th e two solutions (shelf life about one month) applied to a freshly cut surface 
produces a deep red -brown colour in wood containing pentachlorophenol (PCP).  DEAS 326: 2023 
8 © EAC 202 3 – All rights  reserved  
 Bibliography  
EAS 326:2002 , Copper/chromium/arsenic composition for the preservation of  timber — Speci fication  
 DEAS 326: 20 22   
 
© EAC 2022 – All rights  reserved