KENYA STANDARD  DKS 1804-5:2017 
                ICS 71.100.50 
 
 
 
 
 
 
  
 
 
 
  
 
 
 
 Wood preservatives 
 
Part 5:  
 
Field test method for determining the relative 
protective effect of a wood preservative on wood in contact with the soil 
 
   
 
 
 
 
  
 
 
 
 
  
   
 
  
 
   
©KEBS 2006                 First Edition 2006 
 
   DKS 1804-5:2017  
ii    KEBS 2017 — All rights reserved   
 
TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical Committee. 
 1. Marlow Link Timber  
2. KAKUZI 
3. HIGHCHEM  4. Millennium Trading House Limited 
5. National Environmental Management Authority (NEMA) 
6. Kenya Forestry Research Institute (KEFRI) 
7. Pest Control Products Board (PCPB) 
8. University of Eldoret 9. PEMAK 
10. Alogo Enterprises 
11. COSTEK ALMA 12.      Kenya Power   
13. Kenya Wood Preservers Association 
14. Muringa holdings 15 Kenya Bureau of Standards – secretariat 
 
  
 
  
 
REVISION OF KENYA STANDARDS 
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions for 
improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome. 
 
  
 
  
 
  
© Kenya Bureau of Standards, 2003 
  
Copyright. Users are reminded that by virtue of section 6 of th e Copyright Act, Cap. 130 of the Laws of Kenya, copyright subsis ts in all Kenya 
Standards and except as provided under secti on 7 of this act, no Kenya Standard produced by Kenya Bureau of Standards may be 
reproduced, stored in a retrieval system in any form or transmitted by any means without  prior permission in writing from the M anaging 
Director. 
 
 
 
 
 
 
 
ISBN  9966-19-406-1  
 
 
 KENYA STANDARD  DKS 1804-5:2017  
KEBS 2003 — All rights reserved   iii            ICS 71.100.50  
 
 
 
  
 
  
 
 
 
  
 
 
 
Wood preservatives 
 
Part 5:  
 
Field test method for determining the relative 
protective effect of a wood preservative on wood in contact with the soil 
 
 
 
 
 
  
 
     
 
  
 
KENYA BUREAU OF STANDARDS (KEBS) 
 
Head Office:  P.O. Box 54974, Nairobi-00200, Tel.: (+254 020)  605490, 602350, Fax:  (+254 020) 604031 
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region    Lake Region         Rift Valley Region  
P.O. Box 99376, Mombasa-80100  P .O. Box 2949, Kisumu-40100       P.O. Box 2138, Nakuru 20100 
Tel.: (+254 041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396       Tel.: (+254 051) 210553, 210555 
Fax: (+254 041) 229448    Fax: (+254 057) 21814 
 
 DKS 1804-5:2017  
iv    KEBS 2017 — All rights reserved   
 
Foreword 
 
This Part 5 of this Kenya Standard was adopted by the Wood Poles Technical Committee under the guidance 
of the Building and Civil Engineering Industry Standa rds Committee, and it is in accordance with the 
procedures of the Bureau. 
 
The method is primarily concerned with protection against fungal attack.  However, it can also be used in areas where a termite hazard exists.  It should also be noted that fungal decay may alter the resistance of a 
stake to termite attack and that termite attack may obliterate evidence of fungal decay. 
 The main objective of the method described is to evaluate the effectiveness of a preservative relative to a 
reference preservative.  For this reason, permeable timber is used throughout so that the protective effect of a 
wood preservative for various levels of retention can be determined.  
However, it is recognized that modifications of this method may be used for other purposes (e.g. to determine 
the relative efficacy of a preserva tive treatment or to det ermine the natural durabilit y of the heartwood or 
sapwood of a selected timber species). 
 
The method is intended for determining the relative protective effect of a preservative on wood in contact with 
soil. 
 The test should run for a minimum period (usually five years or until the point of failure) before any 
interpretation of the results can be made. 
 Since the wood samples are partly buried in the soil outdoors during the test period, variations in test 
conditions from one test site to another cannot be avoided.  Differences in climate, soil conditions and 
microflora will inevitably influence the general rate of decay.  However, by comparing the results obtained for stakes treated with the test product with those obtained for stakes treated with a reference preservative and 
those obtained with untreated control stakes, the relative protective effectiveness of the product under test can 
be evaluated.  
This standard is an adoption of the document:  
 
DIN EN 252-1990:  Wood preservatives field test method for determining the relative protective effect of 
a wood preservative on wood in contact with the soil. 
 The use of this document is hereby acknowledged with thanks.  
 KENYA STANDARD  DKS 1804-5:2017  
KEBS 2003 — All rights reserved  1   
Wood preservatives  
 
Part 5:  
 
Field test method for determining the relative protective effect of a wood 
preservative on wood in contact with the soil 
 
 
1 Scope 
 
This Kenya Standard describes a field test method for determining the relative effectiveness of wood 
preservatives that are applied by vacuum/pressure impregnation or other processes giving complete penetration 
in order to prevent degradation of timber in contact with soil by micro-organisms.  This method shall may also be 
used in areas in which a termite hazard exists. 
 
The protective effect of the test preservative is assessed in relation to the effect of a reference preservative 
applied by a standard treatment.  The relationship between the results of this field test and performance in service may vary for different preservatives. 
 
2 Field of application 
 
The method is suitable for testing any type of preservative, providing that complete penetration of the test stakes is achieved. 
 
After suitable modification, it is possible to assess the effectiveness of a preservative product in other wood species or its effectiveness when applied by methods ot her than vacuum and pressure  impregnation, provided 
that a complete impregnation of the test stakes is achieved.
 
 
3 Principle 
 
Wood stakes are treated with preservative solutions to give a range of preservative retentions.  After drying and, 
if necessary, an appropriate fixation period, the stakes are partially buried in soil in selected outdoor test sites.  A single site is regarded as adequate. 
 
The stakes are regularly inspected and their condition compared with that of untreated control specimens and that of a group of stakes treated with a reference preservative both of which indicate the aggressiveness of the 
soil at a particular site. 
 
4 Wood Specimens  
 
4.1 Wood species 
 
Wood species sensitive to attack by micro-organisms, which can be completely penetrated with preservative, 
shall be chosen as follows: 
 
i) for every test, the sapwood of Pinus sylvestris (Linnaeus) (European redwood, Scots pine) shall be be as 
per KS 516 used [PM1]; 
ii) it is recommended that a hardwood species of local importance be included if the preservative is expected 
to be used in this type of wood; DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  2iii) if desired, ot her wood species may be in corporated in the test. 
4.2 Wood quality 
 
The wood shall be of uniform growth and free from knots,  cracks, stain, decay, insect holes or other defects.  
Stakes of resinous appearance shall be avoided.  The wood shall not have been water-stored, floated, 
chemically treated or steamed. 
 The wood shall show an average rate of growth of 2.5 to 8 annual rings per 10 mm. 
 
If additional wood species are to be used, the variation is the number of annual rings for each species shall be 
mentioned in the report.  The test report shall also include the mean density for the wood used in the preparation 
of the stakes. 
 
4.3 Characteristics and dimension of stakes 
 
Stakes for test shall be cut from the test wood(s) as follows: 
 Each stake shall be straight-grained and planed to within the thickness tolerance indicated.  When viewed at the 
cross-cut end, the rings shall be oriented tangentially to one of the 50 mm edges to within  15. 
 
The stakes dimensions shall be 
  (500  1) mm x (50  0.3) mm x (25  0.3) mm, 
when measured at a moisture content of (14  2) % m/m. 
 
Each test shall be carried out with stakes of comparable density, and any stakes in a test batch which have 
densities outside the range  15 % of the mean density shall be rejected. 
 
Stakes may be pointed prior to testing or after treatment.  If this is done before treatment, the calculation of the 
stake volume for use in determining the preservative retention should take this into account. 
 
NOTE Additional stakes of different dime nsions may also be included in the tests. 
 
4.4 Number of stakes 
 
At least ten stakes per site for each preservative and retention shall be tested.  To avoid inclusion of ‘abnormal’ 
specimens in the test groups, a greater number shall be  treated so that the required number can be selected 
after treatment.  Additional stakes may also be included for chemical analysis, to aid determination of retention 
and/or distribution ( see 6.3). 
 
To assess the severity of the site conditions, a series of at least 10 untreated control stakes shall be included on 
each site ( see Clause 8).  Such stakes shall be regularly installed in the test site. 
 
Include on each site at least two series of 10 standard reference stakes of Pinus sylvestris  treated according to 
6.2 with a reference preservative ( see Clause 7) to at least two different retention levels. 
 
4.5 Labelling of stakes 
  
Each stake shall be adequately labelled with an inert, durable label or tag. 
 
5 Sample of wood preservative 
 
The sample shall be representative of the preservative to be tested.  It shall be stored and handled in 
accordance with the manufacturer’s specifications.   DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  3 
 
6 Conditioning and treat ment of the stakes 
 
6.1 Drying  
 
The stakes shall be air-dried inside to a moisture content at which a good penetration of the preservative can be 
obtained.  For vacuum/pressure impregnation, the moisture content of the specimens shall be (14  2) %. 
 
6.2 Treatment process  
For the reference stakes and, unless otherwise specified, for test stakes, a full-cell process is to be used.  Initial 
vacuum shall be more than 90 % (<10 kPa)1) and maintained for  at  least 30 minutes.   A  pressure  of  at  least 
1 MPa shall be applied for at least 90 minutes.  Complete records of treatment shall be made for each batch. 
 
6.3 Determination of retention of wood preservative 
 
Before treatment, calculate the volume of each stake from its dimensions ( see 4.3). If a stake has been pointed 
before treatment, this shall be taken into account in the calculation.  Determine the mass of each stake by weighing to an accuracy of 0.5 g.  
 
After treatment, allow the stake to drain for several minutes or wipe off with a cloth any access solution from the surface.  Reweigh each stake to an accuracy of 0.5 g to determine the mass of treatment solution absorbed. 
 
Calculate the retention level for each stake from the mass of treatment solution absorbed, the concentration of the treatment solution and the calculated stake volume.  Express the retention in kilograms of preservative per 
cubic metre of wood.  Calculate the mean retention for each series of test stakes. 
 
Stakes with a retention deviating more than 10 % from the mean value shall be rejected.  
NOTE If a high volatile solvent is used as the carrier, it may be necessary to calculate the ret ention, on the basis of chemica l analysis, for 
additional stakes treated for this purpose ( see 4.4).  It may also be desirable to carry out a chemical analysis to determine the retention or 
distribution of preservatives within the stakes before and at intervals during the exposure period. 
 
If the retention is calculated from analysis, the methods of sampling and analysis shall be indicated in the test 
report. 
 
6.4 Range of preservative retention 
 
Test each preservative with at least three and preferably five different retention levels.  These different levels 
shall be achieved by using freshly prepared preservative solutions at different degrees of dilution and without varying the treatment conditions. 
 
NOTE Use a fresh solution for each dilution;  the dilution of a quantity of solution which has already been used may be unsatisf actory 
because absorption may have occurred du ring the previous treatment schedule. 
 
The mean retention for the series shall correspond to the value recommended by the developer or manufacturer 
as suitable for use with wood in contact with soil (x kg/m3).  A suitable range would then be: 0.25 x, 0.5 x, 2 x 
and 3 x kg/m3.  A narrower range may be used if sufficient information exists on the effective range of the  
product (e.g. a geometrical series with a factor of 1.7).  
 
If the preservative is unsuitable for dilution, different retention levels shall be achieved by varying the treatment parameters given in 6.2 provided that complete penetration is obtained (
see Clause 2). 
 
                                                     
1 ) 1 kPa = 10 mbar  DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  4 
 
6.5 Post-treatment con-treatment conditioning of stakes 
 
For those products requiring a fixation period, the recommendations of the manufacturer should be followed.  
For the reference preservatives, the stakes shall first be close-stacked, each retention group separately, and 
kept close-stacked, each retention group separately, and kept wrapped for an appropriate period in polyethylene or similar material to avoid rapid drying. 
 
7 Reference stakes 
 
7.1 Reference preservative 
 
Stakes of Pinus sylvestris  sapwood shall be treated according to 6.2 using a reference preservative which has 
the following composition: 
 
CuSO 4.5H 2O 35.0 % m/m 
K2Cr2O7  45.0 % m/m  
As2O5.2H 2O 20.0 % m/m 
 
The chemical purity of these substances should be at least 98 % m/m. 
 
Two dry salt retentions shall be used approximating to 9 kg/m3 and 2 kg/m3, respectively.  The precise retentions 
obtained will be dependent on  the  concentration  and uptake of the solution.  For instance, at an uptake of 600 I/m
3 these loadings will be achieved with solution concentrations of 1.5 % (m/ V) and 0.3 % (m/ V), respectively.  
The uptake of Pinus sylvestris  sapwood should be in the region of 600 – 700 I/m3. 
 At least 10 stakes shall be tested with each preservative concentration. 
 
7.2 Alternative reference preservative 
 
If it is not possible to use a preservative containing arsenic, the reference stakes may be treated with any other 
alternative preservative as registered by Pest Control Products Board (PCPB). The list of registered products 
can be found in PCPB website, www.pcpb.or.ke.  
 
Chemical purity of individual components should be as in the fao specification..  
 
Two dry-salt retentions shall be approximating to 17 kg/m3, respectively.  The precise retentions obtained will be 
dependent on the concentration and uptake of the solution.  For instance at an uptake of 600 I/m3 these 
loadings will be achieved with solution concentrations of 2.8 % (m/V) and 0.7 % (m/V), respectively. The uptake 
of pinus sylvestris sapwood should be  in the region of 600 – 700 I/m3.  
 
At least ten stakes per preservative concentration shall be tested.  
 
NOTE Additional reference preservatives and wood species may be employed as required If it is not possible to 
use a preservative containing arsenic, the reference stakes may be treated with an alternative preservative 
although this preservative is unsuitable for areas where attack by termites is expected.  This preservative shall 
have the following composition:  
 
CuSO 4.5H 2O  50.0  % m/m  
K2Cr2O7   48.0  % m/m  
CrO 3    2.0   % m/m  
   DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  5Chemical purity o f individual components should be at least 98%.  
 
Two dry -salt retentions shall be approximating to 17 kg/m3, respectively.  The precise retentions obtained will be 
dependent on the concentration and uptake of the solution.  For instance at an uptake of 600  I/m3 these loadings 
will be achieved with solution concentrations of 2.8 % (m/ V) and 0.7 % (m/ V), respectively. The uptake of pinus 
sylvestris  sapwood should be in the region of 600 – 700 I/m3. 
 
At least ten stakes per preservative concentration shall be tested.  
 
NOTE  Additional reference preservatives and w ood species may be employed as required . 
 
8 Untreated control stakes  
 
A series of at least ten untreated control stakes shall be included in each test site and replaced when they fail. 
 
If no subsequent test stakes have been installed, a new control series should be added when nine of the ten stakes per series have reached rating of 3 or more.  Before installation, the control stakes shall be seasoned and 
stored in the same way as treated specimens. 
 The object of using untreated control specimens is to compare the rate of attack of untreated wood with that of 
wood treated with the preservative under test and that of wood treated with the standard reference preservative.  
The rate of decay in the control specimens indicates the aggressiveness of the test site. 
 
9 Test sites 
 
9.1 Number of test sites 
 
The method is valid using one test site.  However, it may be useful to select, two or more test sites having 
different conditions of climate, types of soil, etc. 
 
9.2 Selection of site 
 
The area chosen for the field trials should be known to have a high pre-dilection for the pest. 
 
9.3 Condition of the test site 
 
The land selected for the test site shall be plane and moist, but well drained and have a uniform soil character.  
Heavy clayey soil and other types of soil liable to be water-logged as well as very dry soil should be avoided.  In 
some countries, the fire hazard in summer must be considered very seriously and the site selected and protected accordingly. 
 
In order to ensure the reproducibility of, and to reduce fl uctuations in, the test results, avoid abundant vegetation 
on the site.  A very dense turf, for example, may lead to poor contact between the soil and the stake surface and 
high and dense vegetation may extend or shift the zone of the stake that will be exposed to attack. 
 
The vegetation shall be trimmed in such a way that the buried stakes are exposed as far as possible.  Chemicals 
to control the growth of vegetation (herbicides) may affect the fungal attack and shall therefore not be used. 
 
9.4 Installation of stakes on the test site 
 
The stakes for each test series shall be installed vertically at random within appropriate section of the test site, 
with a spacing of at least 300 mm.  The stakes shall be buried to half their length (250 mm).  A template 
facilitates installation. 
 DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  6The stakes shall not be hammered in the soil, since this may damage the wood (fractures, splits) and influence 
the test results.  A spike, a spade or other convenient tool may be used to make a suitable hole in the ground.  
When inserting the stakes, it is important to pack the soil tightly about the stake so as to provide a good contact. 
 
10 Inspections 
 
The stakes shall be examined annually2).  To facilitate evaluation of attack, inspection shall be made at a time 
when the moisture content of the wood is above the fibre saturation point.  However, inspections during rainfall should be avoided since a very wet stake surface will make the evaluation more difficult. 
 
Ideally, two persons with good knowledge of the behaviou rs of wood should cooperate in the inspections.  If 
possible these persons should be responsible for the yearly inspections of stakes in a preservative test in order 
to avoid conflicting procedures. 
The inspection is started with a light blow on one of the 50 mm wide faces of the stake when still in the ground to find out if the strength has been so reduced that it breaks.  If the stake does not break, withdraw it from the 
ground and remove the soil adhering to it while ensuring that the stake and its test position are not adversely 
affected.  Examine, without magnification, all sides of the stake for any changes in the wood (e.g. alterations in colour, form or texture and presence of fungal formation (mycelium, strands, sporophores, etc)). 
 
To determine any change in surface hardness of the wood, a blunt-ended instrument may be used for probing.  
However, the stake should be inspected without undue damage or removal of softened wood as this would 
destroy the surface of the wood and alter the test conditions.  
After the inspection, the stake is carefully reinstalled into its original hole.  The soil is carefully pressed against it 
so that a good contact is assured between the soil and the buried part of the stake.  The stake shall be buried to the same depth as that before inspection as the most severe attack occurs in the ground line. If a template was 
used during installation, the same template should be used for reinstallation. 
 Other examinations (e.g. bending tests under carefully controlled conditions) may be carried out at these 
intermediate checks. 
 
11 Evaluation 
 
Evaluation for the extent of attack is based on a number of observations which cannot be expressed in absolute terms.  In addition, the apparent condition of an individual stake may vary slightly from time to time, depending 
on the climate conditions before and during the inspection. It is therefore important not to make the rating procedure too elaborate.  If there is any uncertainty whether an individual stake should be given one of the 
ratings, it is strongly recommended that the lower-numbered rating be used. 
 
11.1 Attack by micro-organisms 
 
Usually, fungi are the most destructive micro-organisms on wood in contact with soil. The rating system shown in 
Table 1 shall be used to evaluate the extent of attack by micro-organisms on stakes.  
Table 1 — Rating system for evaluating extent of damage on micro-organisms 
 
Rating Classification De finition of condition 
0 No attack No change perceptible by the means at the disposal of the inspector 
on site. 
                                                     
2) During the early phase of the test, it may be necessary to examine untreated stales more frequently.    DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  71 Slight attack Perceptible changes, but very limited in intensity, extent or distribution: 
– obvious changes such as a change in colour or very superficial 
decay, softening of the wood being the most common symptom, to 
an apparent depth of about 1 mm. 
2 Moderate attack Noticeable changes of a moderate extent, with the following 
symptoms; 
– obvious changes such as soft ening of the wood to a depth of 
approximately 2 to 3 mm over the whole test piece along the burial depth. 
3 Severe attack Significant changes: 
Marked decay of the wood to a depth of 3 to 5 mm over a wide area 
(e.g. soft rot or other types of dec ay over all the surfaces of the 
specimen along the burial depth) or by  softening to a greater depth (10 
to 15 mm) over a smaller area (e.g. white rot over a few mm2) 
4 Failure  Impact failure of the stake on site. 
 
Add up the ratings for all stakes for each retention and divide by the number of takes to obtain an average rating 
for each retention of the preservative tested. 
 
11.2 Attack by termites 
 
Though the method is not designed to test specifically the resistance to termites, when these insects occur it is necessary to evaluate their attack according o an adequate system. 
 
The evaluation of the extent of termite attack shall be made separately according to the following rating system in Table 2: 
 
Table 2 — Rating system for evaluating the extent of termite attack 
 
Rating Classification Definition of condition 
0 No attack No sign of attack 
1 Slight attack Perceptible, but slight attack, taking the form of a very 
superficial deterioration (1 to 2 mm deep), at some points or 
over small areas. 
2 Moderate attack Moderate attack:  deteriorated areas covering several cm2 
and 2 to 5 mm deep, or by scattered points down to a depth exceeding 5 mm, or by different combinations of the two 
types of attack. 
3 Severe attack Severe attack:  extensive and deep destruction (5 to 10 mm) 
or tunnels reaching to the center of the stake, or by different combinations of the two types of attack. 
4 Failure  Extremely severe attack; penetration throughout: total or 
almost total destruction of the stake. 
 
Add up the ratings for each retention level and divide by the number of stakes to obtain an average rating for each retention of the preservative tested.  
If all the stakes for a given retention have failed (average rating: 4), the average life of the stakes in this group 
shall be calculated, together with the standard deviation. DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  8 
In tropical and subtropical regions, a shorter exposure period may be acceptable.  However, in any case, the 
average rating for the reference stakes at the lower retention level shall not be less than 1.0.  
It is advisable to continue the test, with inspections at suitable intervals, over a prolonged period, in order to 
determine ultimate life.  Ideally, the test should be continued until all stakes have failed. 
 
13 Test report 
 
The test report shall include the following information: 
 
i) the number of this Kenya Standard; 
ii) the name of supplier; 
iii) the name and type of preservative tested and whether the formulation was known; iv) the solvent or diluent used; 
 
v) the wood species used and the mean density of the wood selected; vi) any additional wood species ; used, including the stake dimensions, the number of annual rings per 10 
mm and mean density of the wood selected; 
vii) number of replicates; 
viii) the concentrations of preservative tested; 
ix) the date of treatment and the treatment conditions: 
a) initial vacuum…… kPa/…… min 
b) pressure……kPa/…… min 
c) final vacuum……kPa/ ….…min 
x) the average quantity of solution, in litres per cubic metre, absorbed for each series, and the minimum and 
maximum values; 
xi) the average retention of preservative, in kilograms per cubic metre for each series, and the minimum and 
maximum values; 
xii) the reference preservative (composition, concentration, average retention, and the minimum and 
maximum values); 
xiii) the method of post-treatment conditioning and the dates; 
xiv) the date of installation of the stakes on the site; 
xv) a brief description of the site including its location; xvi) the date(s) of inspection of the stakes; 
xvii) the duration of the exposure period; 
xviii) the rating system used in the evaluation (
see  Clause 11) and the degree of deterioration; 
xix) the average ratings and average life, with standard deviations, for control special specimens, reference 
stakes and test stakes; 
xx) the name of the organization responsible for the report and the date of issue; xxi) the name and signature of the person(s) in charge of testing; 
xxii) identity of species of fungi/termite present in the area; 
xxiii) the following note:
   DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  9‘The interpretation and conclusions that can be drawn from a test report demand a specialized 
knowledge of the subject of wood preservation and, for this reason, this test report does not of itself 
constitute an approval certificate’. 
 
The test report shall also list any deviation from the described test method and any factors that may have 
influenced the results.  
 
  
 
  
 
  
 
  
 
 
 
  
Annex A 
(informative) 
 
General 
 
In tropical regions where the climate and biological conditions are different, the principle of this standard can be 
adopted.  The choice of the species depends upon the region in which the test is to be established; 
nevertheless, the choice of the species shall be made from among the main species of the region.  It should be a susceptible species and one which can be completely penetrated by the preservative.  The ratings for the extent 
of attack remain the same.  Nevertheless, it is necessary to distinguish the different agents of attack and their 
respective intensities.  
 
  
 
  
 
  
 
  
 
  
 
 
 
  DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  10  
 
  
 
  
 
  
 
 
 
  
 
  
 
  
 
  
 
Annex B 
(normative) 
 
Example of a test report  
 
Number of this Kenya Standard: KS 1804:Part 5 
Name of supplier:  Company P 
Name and type of product: XYZ; powder 
Solvent or diluent used: Water 
Wood species used and density Scots pipe ( Pinus sylvestris Linnaeus) sapwood: 
480 kg/m3 
Additional wood species used: European beech ( Fagus sylvatica Linnaeus); 3 to 6 annual 
rings per 10 mm; 630 kg/m3 (This test is specified in another 
test report).
Number of replicates: 10 
Concentrations tested (% m/m) 0.6 – 1.2 – 2.4 – 4.8 – 7.2 
Date of treatment and treatment conditions: 2001-03-15  
Full-cell process, as specified in the standard 
Average absorption: See Table B.1 
Average retention: See Table B.1 
Reference preservative used: Reference preservative having the following composition: 
CuSO 4 .5H 2O  35 % m/m 
K2Cr2O7 45 % m/m 
As2O5.2H 2O 20 % m/m
Post-treatment conditioning method: Stakes dried after impregnation in open piles for 45 days, at 
15 to 20 C 
Date of installation on the site: 1979-05-02   DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  11Name of location of test site: Maseno, Kenya; 28 km west of Kisumu 
Date of inspection 1994-06-10 
Exposure period: 5 years 
Rating system used in the evaluation and 
degree of deterioration See Table B.2. 
Average ratings and average life of 
control specimens, reference stakes and 
test stakes See Table B.1. 
 
NOTE The interpretation and conclusions that  can be drawn from a test report demand a specialized knowledge of the subject of w ood 
preservation and, for this reason, this test report does  not of itself constitute an approval certificate. 
 
 
 
    
 
    Table B.1 — Results from XYZ on scots pine in contact with soil after 5 years exposure 
 
Type of 
stakes Concentrations 
tested 
 
% m/m Average 
absorption 
 
L/m3 
(sapwood) Average 
retention 
 
Kg/m3 
(sapwood) Average ratings 
based on the evaluation of 
attack 
of individual 
stakes Average life 
 
 
Years 
Test 
stakes 0.6 
 
 
1.2 
 
 
2.4 
 
 
            4.8 
 
 
7.2 630 
(606-653) 
 
621 
(600-645) 
 
629 
(601-663) 
 
637 
(615-648) 
 
615 
(595-640) 3.78 
(3.64-3.92) 
 
7.45 
(7.20-7.74) 
 
15.10 
(14.42-15.91) 
 
30.58 
(29.52-31.10) 
 
44.28 
(42.84-46.08) 4 
 
 
 
2.5  0.3a) 
 
 
0.1 
 
 
0 
 
 
0 3.2  0.3a) 
Reference 
stakes             0.3 
 
1.3 635 
(601-658) 
 
626 
(609-649) 1.91 
(1.80-1.97) 
 
814 
(7.92-840) 2.7  0.2 a)  
Untreated 
control 
specimens 0.0 0 0 4 2.1 DKS 1804-5:2017  
© KEBS 2017 — All rights reserved  12  
a) Standard deviation.  
 
 
 
 
 
    
 
     
 
    
 
Table B.2 — Explanation of the principle for evaluation of the attack 
 
The stakes have been attacked by micro-organisms and not by termites.  The rating system in 
Table B.2 has been used. 
 
 
Rating Classification De finition of condition 
0 No attack No change perceptible by the means at the disposal of 
the inspector on site. 
1 Slight attack Perceptible changes, but very limited in intensity, extent 
and/or distribution: 
 – obvious changes such as change in colour or a 
superficial decay, softening of the wood being the 
most common symptom, to an apparent depth of 
about 1 mm. 
2 Moderate attack Noticeable changes of a moderate extent, with the 
following symptoms: 
 – obvious changes such as softening of the wood to a 
depth of approximately 2 to 3 mm over the whole test piece along the burial depth.   DKS 1804-5:2017 
© KEBS 2017 — All rights reserved  133 Severe attack Significant changes: marked decay of the wood to a 
depth of 3 to 5 mm over a wide area (e.g. soft rot or other types of decay over all the surfaces of the 
specimen along the burial depth) or by softening to a 
greater depth (10 to 15 mm) over a small area (e.g. white rot over a few mm
2) 
 
4 Failure Impact failure of the stake on site. 
 By adding up the ratings for all stakes for each retention level, and dividing by the number of stakes, an average 
rating for each level of retention of the preservative tested has been obtained.  
If all the stakes at a given retention have failed (average rating: 4) the average life of the stakes in the group has 
been calculated, together with the standard deviation.