DRAFT UGANDA STANDARD  
  DUS EAS 326
First Edition
2010-mm-dd
 
Reference numbe r
DUS EAS 326: 2002
 © UNBS 2010
  
Copper/chromium/arsenic composition for the preservation of 
timber — Specification 
 DUS EAS 326: 2002  
 
© UNBS  2010 – All rights reserved ii Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2010 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala  
Uganda 
Tel: 256 41 505 995 
Fax: 256 41 286 123 
E-mail: unbs@infocom.co.ug
Web: www.unbs.go.ug  
 DUS EAS 326: 2002 
© UNBS  2010 - All rights rese rved                iii National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of U ganda. UNBS is mandated to co-ordinate the elaboration 
of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council. 
This Draft Uganda Stand ard, DUS EAS 326:2002,  Copper/chromium/arsenic composition for the preservation 
of timber — Specification, is identical with and has been reproduced from an East African Standard, EAS 
326:2002, Copper/chromium/arsenic composition for the preservation of timber — Specification,  and is being 
proposed for adoption as a Uganda Standard.  
This standard was developed by the Furniture Standards Technical Committee (UNBS/TC 12).  
Wherever the words, “East African Standard" appea r, they should be replaced by "Uganda Standard." 
 
 EAS 326:2002 
ICS 77.100.50 
HS 2931.00.20 
© EAC 2002 First Edition 2002 
 
  
 
 
 
  
 
EAST AFRICAN STANDARD 
 
Copper/chromium/arsenic composit ion for the preservation of 
timber — Specification 
 
  
 
  
   
 
 
 
 
 
 
 
  
 
 
 
 
 
 
EAST AFRICAN COMMUNITY  
 EAS 326:2002  
ii © EAC 2002 — All rights reserved  
 
Foreword 
 
Development of the East African Standards has been necessitated by the need for harmonizing 
requirements governing quality of products and services in East Africa. It is envisaged that through harmonized standardization, trade barriers which are encountered when goods and services are 
exchanged within the Community will be removed.  
 In order to achieve this objective, the Partner States in the Community through their National Bureaux 
of Standards, have established an East African Standards Committee.  
The Committee is composed of representatives of the National Standards B odies in Partner States, 
together with the representatives from the private sectors and consumer organizations. 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 procedures of the Community.  
East African Standards are subject to review, to keep pace with technological advances. Users of the 
East African Standards are therefore expected to ensu re that they always have the latest versions of 
the standards they are implementing.  
 
© East African Community 2002 — All rights reserved
* 
East African Community  
P O Box 1096  
Arusha  
Tanzania  
Tel: 255 27 2504253/8 Fax: 255-27-2504481/2504255 
E-Mail: eac@eachq.org
 
Web: www.each.int 
                                                 
* © 2002 EAC — All rights of exploitation in any form and by any means reserved worldwide for EAC Partner States’ NSBs.  
 EAS 1:2002  
© EAC 2002 — All rights reserved iii  
Introduction 
 
Copper, chromium and arsenic composition is a water borne salt timber preservative for application to 
timber by vacuum pressure impregnation. 
 
The preservative is a finely dispersed paste of viscosity and solubility so as to facilitate easy and rapid preparation of aqueous treating solutions so as to preserve timber against insect attack, termites and 
fungal decay. 
 This East African Standard does not purport to address all of the safety problems associated with its use.  It is the responsibility of the user of this Ea st African Standard to es tablish appropriate safety 
and health practices and determine the applicability of suitable regulatory limitations prior to 
utilization.  Such regulations shall govern the use of wood preservatives in East Africa.  
In the preparation of this East African Standard assistance was drawn from the following standards: 
 BS 4072:1999, Copper/chromium/arsenic preparations for wood preservation  published by the British 
Standards Institution. 
 
ISO 4793:1980, Sintered filter for laboratory use — Specification  published by the International 
Organization for Standardization. 
 
In reporting the results of a test made in accordance with this East African Standard, if the final value observed or calculated is to be rounded off, it  shall be done in accordance with EAS 124, Rounding 
off numerical values . 
 The annexes  are integral parts of this East African Standard. They record the apparatus necessary 
for testing. However, for the purpose of this East African Standard, it is supposed that equipment at 
testing laboratories will meet the demands given in this East African Standard.   
 
 EAS 326:2002  
© EAC 2002 — All rights reserved  1  
Copper/chromium/arsenic composit ion 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 
 
For the purpose of this East African Standard, the following references shall apply: 
 
EAS 123, Water — Distilled quality — Specification 
 
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 
 
EAS 124, Rounding off numerical values  
 
3 Terms and Definitions 
 
For the purpose of this East African Stan dard, the following definitions shall apply: 
 3.1 liquid junction 
any junction between two electrolyte solutions of different composition 
 3.2 sintered glass filter  
a filter produced from porous materials formed by the thermal bonding of particles  
3.3 
pore size index   
a characteristic of a filter related to pore diameter  
3.4 
permeability   
a characteristic of a filter related to the rate of flow through it under specified conditions 
 3.5 test solution  
the solution of which the pH value is required 
 3.6 pH meter 
a 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 
 
3.7 
electrode 
an external system that incorporates a fitting soluti on and a means, such as a ceramic plug or forming 
the liquid junction  EAST AFRICAN STANDARD EAS 326:2002  
2 © EAC 2002 — All rights reserved 4 Composition 
 
4.1 Raw materials  
The preservative shall consist essentially of a mixture of compounds of copper (ii), chromium (vi) and 
arsenic (v). 
 The mixture of compounds shall be selected to be consistent with this Clause and 7.1. 
 
The preferred mixtures of compounds are either  a) hydrated copper (ii) sulphate, hydrated sodium or potassium dichromate and hydrated diarsenic 
pentoxide, or 
 b) copper (ii) oxide, chromium (vi) oxide and diarsenic pentoxide. 
 
NOTE  Attention is specially drawn to the toxic nature of the formulations and their solutions that may be injurious to health if 
adequate precautions are not taken.  Therefore, particular care and the use of appropriate protective clothing is necessary.  Also special precautions are required for disposal of these solutions. 
 
4.2 Formulation 
 The nominal composition of the two types of preservatives (designated Type 1 and Type 2) together 
with minimum concentration of each component sh all 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. 
 
The preservatives shall be supplied as mixtures. 
 
NOTE The usual forms are dry ingredients, paste or concentrated solutions. 
 
Containers shall carry information on the mass of preservatives equivalent to unit mass of nominal 
composition.  
Preservatives as supplied may differ in composit ion from the nominal composition 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 compositions 
 
Type 1 Type 2 Ingredients 
Nominal Minimum Nominal Minimum 
Copper (expressed as CuSO 4.5H2O)% m/m  32.6 29.5 35.0 31.5 
Chromium (expressed as Na 2Cr2O7.2H 20)% m/m 41.0 37.0 45.0 40.5 
Arsenic (expressed as As 205.2H2O)% m/m 26.4 23.5 20.0 18.0 
 
Total composition  
100.0  
90.0  
100.0  
90.0 
 
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 higher than 2.8. EAS 326:2002  
© EAC 2002 — All rights reserved  3  
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.  EAS 326:2002  
4 © EAC 2002 — All rights reserved  
Annex A 
(normative) 
 
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 approximately 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 accordance with (A.3) at 27 oC + 2 oC using the pH 
meter which is intended for determining a pH value within a broad range. EAS 326:2002  
© EAC 2002 — All rights reserved  5  
Annex B 
(normative) 
 
Determination of insoluble matter 
 
 B.1 Apparatus 
 
B.1.1  Sintered 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 10 g +  0.1 g of the nominal composition to the 
nearest 0.001 g and dissolve it in water, filter and wa sh 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 containing the residue from (B.2) to the drying oven (B.1.2) previously adjusted to 105 
oC + 5oC.  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 until 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: 
 
% 100
31 2×−=mm mm  
 
where 
 
m1 is the mass in g of the sintered glass filter;  
 m
2 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.  
 
 EAS 326:2002  
© EAC 2002 — All rights reserved