UGANDA STANDARD  
  US 839
First Edition
  2009-09-04
 
 
Reference numbe r
US 839: 2009
 © UNBS 2009 
  
Particleboards — Specification   
 US 839: 2009 
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 2009 
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: 256 414 505 995 
Fax: 256 414 286 123 
E-mail: unbs@infocom.co.ug
Web: www.unbs.go.ug  US 839:2009 
iii 
 Contents Page 
Foreword ............................................................................................................................................................iv  
1 Scope ......................................................................................................................................................1  
2 Normative references ............................................................................................................................1  
3 Classification of boards ........................................................................................................................2  
4 Requirements .........................................................................................................................................2  
4.1 General ...................................................................................................................................................2  
4.2 Requirements for general purpose boards for use in dry conditions (Type P1) ............................3  
4.3 Requirements for boards for interior fitmen ts (including furniture) for use in dry 
conditions (Type P2) .............................................................................................................................4  
4.4 Requirements for non load-bearing boards for use in humid conditions (Type P3) .....................4  
4.5 Requirements for load-bearing boards for use in dry conditions (Type P4) ..................................6  
4.6 Requirements for load-bearing boards for use in humid conditions (Type P5) .............................7  
4.7 Requirements for heavy duty load-bearing boards for use in dry conditions (Type P6) ..............8  
4.8 Requirements for heavy duty load-bearing boards for use in humid conditions (Type P7) .........9  
4.9 Supplementary properties ..................................................................................................................10  
5 Verification of compliance ..................................................................................................................10  
5.1 General ............................................................................................................................... ..................10  
5.2 External control ............................................................................................................................... ....10  
5.3 Factory production control ................................................................................................................11  
6 Marking ............................................................................................................................... ..................11  
Annex A (normative)  Voluntary colour coding system for particleboards ...............................................13  
Bibliography ............................................................................................................................... .......................14  
 US 839: 2009 
iv 
 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 Uganda.  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.  
Committee membership 
The following organisations were represented on the Furniture Standards Technical Committee, UNBS/TC 12, 
during the development of this standard: 
• Board City 
• Geotech Engineering 
• St. Joseph Kisubi Technical 
• Kibalika & Son Furniture Ltd 
• Kyambogo University 
• P.G Bison 
• Uganda National Bureau of Standards  
• Uganda Small Scale Industrial Association  
 UGANDA STANDARD US 839:2009
 
 Particleboards — Specifications 
1 Scope 
This Uganda Standard specifies the requirem ents for resin-bonded unfaced particleboards. 
NOTE 1 The application of this standard will be called up in  for construction applications. The values listed in this 
standard relate to product properties but they are not c haracteristic values to be used in design calculations. 
NOTE 2 Such characteristics valuse 
NOTE 3 Particleboards in accordance with this standard may be referred to as P1 to P7-boards. 
NOTE 4 A new grade of board type P3 has been included and is intended for use as a non load-bearing board for use 
in humid conditions. Boards of type P4 to P7 are intended fo r use in design and construction of  load-bearing or stiffening 
building elements, e. g. walls, flooring, roofing and I-beams  
2 Normative references 
The following referenced documents are indispensabl e for the application 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. 
*US 878, Wood-based panels — Determination of formaldehyde content — Extraction method called the 
perforator method  
*US 879-1, Wood-based panels — Determination of dimensions  of boards — Part 1: Determination of 
squareness and edge straightness  
*US 879-2, Wood-based panels — Sampling, cutting and inspection  — Part 2: Quality control in the factory 
*US 879-3, Wood-based panels — Sampling, cutting and inspection — Part 3: Inspection of a consignment of 
panels 
*US 880, Wood-based panels — Performance specifications and requirements for load-bearing boards for use 
in floors, walls and roofs  
*US 881, Wood-based panels for use in construction — Characteristics, evaluation of conformity and marking  
ISO 3340, Fibre building boards — Determination of sand content 
ISO 9427,  Wood-based panels — Determination of density 
ISO 9426,  Wood-based panels — Determination of dimensions of boards 
ISO12460-1, Wood-based panels — Determination of formaldehyde release — Part 1: Formaldehyde 
emission by the chamber method  
ISO 16978, Wood-based panels — Determination of modulus of elasticity in bending and of bending strength 
ISO 16979, Wood-based panels — Determination of moisture content 
ISO 16981, Wood-based panels — Surface soundness — Test method US 839: 2009 
2 
                                                      ISO 16984, Particleboards and fibreboards — Determination of  tensile strength perpendicular to the plane of 
the board 
ISO 16987, Wood-based panels — Determination of moisture resistance under cyclic test conditions 
ISO 16985, Wood-based panels — Determination of dimensional changes associated with changes in relative 
humidity 
ISO 16989, Particleboards and fibreboards — Determination of swelling in thickness after immersion in water  
ISO 16998, Particleboards — Determination of moisture resistance — Part 1: Boil test 
ISO 16999, Wood-based panels — Sampling, cutting and inspection — Part 1: Sampling and cutting of test 
pieces 
3 Classification of boards 
Seven types of boards are classified and are distinguished as follows: 
a) P1 General Purpose boards for use in dry conditions; 
b) P2 Boards for interior fi tments (including furniture) for use in dry conditions; 
c) P3 Non load-bearing boards for use in humid conditions1); 
d) P4 Load-bearing boards for use in dry conditions; 
e) P5 Load-bearing boards for use in humid conditions1); 
f) P6 Heavy duty load-bearing boards for use in dry conditions; and 
g) P7 Heavy duty load-bearing boards for use in humid conditions1). 
4 Requirements 
4.1 General  
4.1.1  Particleboards for all board types shall comply with  the general requirements as listed in Table 1 when 
dispatched from the production fact ory. For certain uses of particle boards (see performance standard EN 
12871), special tolerances are required for the dimensional properties listed under No. 1. In the case of 
dispatch in cut sizes, or of further machined boards (tongued and grooved, and similar), special tolerances for 
properties No. 1, 2 and 3 may be agreed upon. 
 
 
1) Humid conditions are defined in terms of service class 2 of ENV 1995-1-1 which is characterized by a moisture 
content in the material corresponding to a temperature of 20 °C and the relative humidity of the surrounding air only 
exceeding 85 % for a few weeks per year. Boards of this type are suitable for use in biological hazard classes 1 and 2 of 
EN 335-3. US 839:2009 
3 
 Table 1 — General requirements at dispatch 
No Property Test method Requirement 
1a) Tolerances on nominal dimensions: 
• Thickness (sanded) within and 
between boards 
• Thickness (unsanded) within and 
 between boards 
• Length and width ISO 9426  
± 0.3 mm 
± 0.3 mm + 1.7 mm 
± 5 mm 
2a)  Edge straightness tolerance  ISO 9426 1.5 mm per m 
3a) Squareness tolerance  ISO 9426 2 mm per m 
4  Moisture content  ISO 16979 5 % to 13 % 
5a)  Tolerance on the mean density within a board ISO 9427 ± 10 % 
6b) 
 Formaldehyde release according to *US881 
— Class E 1 
Perforator value 
Steady state emission valuec)
— Class E 2 
Perforator value 
 
Steady state emission valuec) 
 
*US 878 
ISO 12460-1 
 
*US 878 
ISO 12460-1  
 
Content ≤  8 mg/100 g oven dry boardd)
Release ≤ 0.124 mg/m3 air 
 
Content > 8 mg/100 g oven dry board 
≤ 30 mg/100 g oven dry board 
Release > 0,124 mg/m3 air 
a) These values are characterized by a moisture content in the material corresponding to a relative humidity of 65 % and a temper ature of 20 °C. 
b) The perforator values apply to boards with moisture contents H of 6.5 %. In the case of particleboards with different moisture content (in the range of 3 % ≤  H ≤10 %) the 
perforator value shall be multiplied by a factor F which can be calculated from the following equation: 
F = - 0.133 H + 1.86 
c) Required for initial type testing other than for established products where initial type testing may also be done on the basis of existing data with EN 120 or ISO 12460-1 
testing, either from factory production control or from external inspection. 
d) Experience has shown that to ensure compliance with these limits, the rolling average of the EN 120 values found from the inter nal factory production control over a 
period of ½ year should not exceed 6,5 mg HCHO/100 g panel mass.
 
4.1.2 For the case of requirement values. the requirements in tables 2 to 11 shall be met by 5 percentile 
values (95 percentile values in the case of thickness swelling) based on the mean values for individual boards 
and calculated in accordance with ISO 16999. In the case of thickness swelling they shall be equal to or less 
than the values in tables 2 to 11 and in the case of al l other properties they shall be equal to or greater than 
the values in tables 2 to 11. 
The values in tables 2 to 11 for both bending strength and modulus of elasticity shall apply to test results 
obtained in the weakest direction in the plane of the panel. 
NOTE  The manufacturer may test the panel in only the main direction if this direction is clearly indicated 
on the machined ready to use panel. 
4.2 Requirements for general purpose boards for use in dry conditions (Type P1) 
Boards of this type shall comply with the requirements given in tables 1 and 2. 
 US 839: 2009 
4 
 Table 2 —— Requirements for specified mechanical properties for general purpose boards for use in 
dry conditions (Type P1) 
Requirement 
Thickness range (nominal),  
mm Property Test 
method Unit 
3 to 6 > 6 to 13 > 13 to 20 > 20 to 25 > 25 to 32 > 32 to 40 > 40 
Bending 
strength ISO 16978 N/mm214 12.5 11.5 10 8.5 7 5.5 
Internal bond  ISO 16984  N/mm20.31 0.28 0.24 0.20 0.17 0.14 0.14 
NOTE  The values are characterised by a moisture content in the material corresponding to a relative humidity of 65 % 
and a temperature of 20 °C.
 
4.3 Requirements for boards for interior fitments (including furniture) for use in dry 
conditions (Type P2) 
Boards of this type shall comply with the requirements given in tables 1 and 3. 
Table 3 — Requirements for specified mechanical properties for boards for interior fitments (including 
furniture) for use in dry conditions (Type P2) 
Requirement 
Thickness range (nominal),  
mm Property Test 
method 
 Unit 
 
3 to 4 > 4 to 6 > 6 to 13 > 13 to 20 > 20 to 25 > 25 to 32 > 32 to 40 > 40 
Bending 
strength ISO 
16978 N/mm213 
 14 13 13 11,5 10 8,5 7 
Modulus of elasticity in bending ISO 
16978 N/mm21 800 
 1 950 1 800 1 600 1 500 1 350 1 200 1 050 
Internal bond ISO 
16984 N/mm20.45 0.45 0.40 0.35 0.30 0.25 0.20 0.20 
Surface soundness ISO 
16981 N/mm20.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 
NOTE The values are characterised by moisture content in the material corresponding to a relative humidity of 65 % and a 
temperature of 20 °C.
 
 
4.4 Requirements for non load-bearing boards for use in humid conditions (Type P3) 
4.1.1 Boards of this type shall comply with the requirements given in tables 1, 4 and 5. 
 US 839:2009 
5 
 Table 4 — Requirements for specified mechanical and swelling properties for non load-bearing boards 
for use in humid conditions (P3) 
Requirement 
Thickness range (mm, nominal) Property Test 
method Unit 
3 to 4 > 4 to 6 > 6 to 13 > 13 to 20 >20 to 25 > 25 to 32 >32 to 40 > 40 
Bending 
strength ISO 
16978 N/mm213 14 15 14 12 11 9 7,5 
Modulus 
of elasticity in bending ISO 
16978 N/mm21 800 1 950 2 050 1 950 1 850 1 700 1 550 1 350 
Internal bond ISO 
16984 N/mm20,50 0.50 0.45 0.45 0.40 0.35 0.30 0.25 
Swelling in thickness, 24 h ISO 
16983 % 17 16 14 14 13 13 12 12 
NOTE  The values for bending properties, internal bond and swelling in  thickness are characterised by a moisture content in the 
material (before treatment in the case of swelling in thickness)  corresponding to a relative humidity of 65 % and a temperature  of 
20 °C.
 
4.1.2  Requirements for moisture resistance, and if applicable swelling, are dependent upon the test 
method employed to assess these properties. Thus, two al ternative sets of requirements (Option 1 and Option 
2) are set out in Table 5 corresponding to the two prin cipal recognised methods of evaluation. It is necessary 
for the manufacturer to show compliance with only one of these two options. 
Option 1 requirements apply to boards subjected to an accelerated ageing test, the so-called "cyclic test in 
humid conditions" described in ISO 16987. Option 2 r equirements apply to boards subjected to the so-called 
"boil test" described in ISO 16998. The glues or adhesiv e systems suitable for the application of Option 1 and 
Option 2 are unrestricted. 
The alkali content of boards shall not exceed 2.0 %,  based on oven-dry mass and total thickness (tested 
analytically) and shall not exceed 1.7 % in the outer layers (by calculation). 
When verifying compliance by external control only th e test option performed and notified by the manufacturer 
shall be carried out. If the option is unknown it will be ne cessary to carry out both se ts of procedures, even 
though compliance is required with only one set of requirements. US 839: 2009 
6 
 Table 5 —Requirements for moisture resistance for non load-bearing boards for use in humid 
conditions (Type P3)  
Requirement 
Thickness range (mm, nominal) Property Testmet
hod Unit 
3 to 
4 > 4 to 6 > 6 to 13 > 13 to 20 > 20 to 25 > 25 to 32 >32 
to 40 > 40 
 
N/mm2 
0.18 
  
0.18  
0.15  
0.13  
0.12  
0.10  
0.09  
0.08 OPTION 1 
Internal bond after cyclic test 
Swelling in thickness after cyclic test  
ISO 
16987 
 
ISO 
16987 % 15 14 14 13 12 12 11 11 
OPTION 2 
Internal bond after boil test  
ISO 
16998  
N/mm2 
0.09  
0.09  
0.09  
0.08  
0.07  
0.07  
0.06  
0.06 
NOTE  The values for internal bond and swelling in thickness after option 1 treatment are characterised by a 
moisture content in the material (before and after cyclic  test) corresponding to a relative humidity of 65 % and a 
temperature of 20 °C. 
The values for internal bond after option 2 treatment are char acterised by a moisture content in the material (before the 
boil test) corresponding to a relative hum idity of 65 % and a temperature of 20 °C.
 
4.5 Requirements for load-bearing boards for use in dry conditions (Type P4) 
Boards of this type shall comply with the requirements given in tables 1 and 6. 
 
Table 6 — Requirements for specified mechanical and swelling properties for load-bearing boards for 
use in dry conditions (Type P4)  
Unit 
 Requirement 
Thickness range (nominal). 
 mm Property Testmet
hod 
 
3 to 4 > 4 to 6 > 6 to 13 > 13 to 20 >20 to 25 > 25 to 32 >32 to 40 > 40 
Bending 
strength ISO 
16978 N/mm215 
 16 16 15 13 11 9 7 
Modulus of elasticity in bending ISO 
16978 N/mm21 950 2 200 2 300 2 300 2 050 1 850 1 500 1200 
Internal bond ISO 
16984 N/mm20.45 0.45 0.40 0.35 0.30 0.25 0.20 0.20 
Swelling in thickness, 24 h ISO 
16983 % 23 19 16 15 15 15 14 14 
NOTE  If it is made known by the purchaser that the boards are intended for specific  use in flooring, walls or roofing the 
performance standard EN 12871 also has to be consulted. This mi ght result in additional requirements having to be complied 
with.. The values for bending properties, internal bond and swelling in thickness are characterised by a moisture content  in t he 
material (before treatment in the case of swelling in thickness) corresponding to a relative humidity of 65 % and a temperature  of 
20 °C.US 839:2009 
7 
  
4.6 Requirements for load-bearing boards for use in humid conditions (Type P5) 
4.6.1 Boards of this type shall comply with the requirements given in tables 1, 7 and 8. 
Table 7 —Requirements for specifi ed mechanical and swelling properties for load-bearing boards for 
use in humid conditions (Type P5)  
Requirement 
Thickness range (nominal). 
mm Property Test 
method Unit 
3 to 4 > 4 to 6 > 6 to 13 > 13 to 
20 > 20 
to 25 > 25 to 
32 >32 to 
40 > 40 
Bending 
strength ISO 
16978 N/mm220 
 19 18 16 14 12 10 9 
Modulus of 
elasticity in 
bending ISO 
16978 N/mm22 550 2 550 2 550 2 400 2 
150 1 900  1 700 1 550 
Internal bond ISO 
16984 N/mm20.50 
 0.50 
 0.45 
 0.45 
 0.40 
 0.35 
 0.30 
 0.25 
 
Swelling in 
thickness, 24 
h ISO 
16983 % 13 12 11 10 10 10 9 9 
NOTE  The values for bending properties, internal bond and swelling in thickness are characterised by a moisture 
content in the material (before treatment in the case of swelling in thickness) corresponding to a relative humidity of 65 % and a temperature of 20 °C. If it is made known by the purchaser that the boards are intended for specific use in flooring, 
walls or roofing the performance standard al so has to be consulted. This might result in additional requirements having to 
be complied with.
 
4.6.2  Requirements for moisture resistance, and if applicable swelling, are dependent upon the test method 
employed to assess these properties. Thus, two alternative sets of requirements (Option 1 and Option 2) are 
set out in Table 8 corresponding to the two principal recognised methods of evaluation. It is necessary for the manufacturer to show compliance with only one of these two options. 
Option 1 requirements apply to boards subjected to an accelerated ageing test, the so-called "cyclic test in humid conditions" described in ISO 16987. Option 2 r equirements apply to boards subjected to the so-called 
"boil test" described in ISO 16998. The glues or adhesiv e systems suitable for the application of Option 1 and 
Option 2 are unrestricted. 
The alkali content of boards shall not exceed 2.0 %,  based on oven-dry mass and total thickness (tested 
analytically) and shall not exceed 1.7 % in the outer layers (by calculation). 
When verifying compliance by external control only th e test option performed and notified by the manufacturer 
shall be carried out. If the option is unknown it will be ne cessary to carry out both se ts of procedures, even 
though compliance is required with only one set of requirements. US 839: 2009 
8 
  
 
Table 8 — Requirements for moisture resistance for load-bearing boards for use in humid conditions 
(Type P5) 
Requirement 
Thickness range (nominal). 
mm Property Test  
method 
 Unit 
 
3 to 
4 > 4 to 
6 > 6 to 
13 > 13 to 
20 >20 to 
25 > 25 to 
32 >32 to 
40 > 40 
 
N/mm2 
0.30 
  
0,30  
0.25  
0.22  
0.20  
0.17  
0.15  
0.12 OPTION 1 
Internal bond after 
cyclic test 
 
Swelling in thickness 
after cyclic test  
ISO 16987 
 
 
ISO 16987  
%  
12  
12  
12  
12  
11  
10  
9  
9 
OPTION 2 
Internal bond 
after boil test  
ISO 16998  
N/mm2 
0.15  
0.15  
0.15  
0.14  
0.12  
0.11  
0.10  
0.09 
NOTE The values for internal bond and swelling in thickness after option 1 treatment are characterised by a moisture content in the material (before and after cyclic test) corres ponding to a relative humidity of 65 % and a temperature of 
20°C. The values for internal bond after opt ion 2 treatment are characterised by a mo isture content in the material (before 
the boil test) corresponding to a relative hum idity of 65 % and a temperature of 20 °C.
 
 
4.7 Requirements for heavy duty load-bearing boards for use in dry conditions (Type P6) 
Boards of this type shall comply with the requirements given in tables 1 and 9. 
Table 9 — Requirements for specified mechanical a nd swelling properties for heavy duty load-bearing 
boards for use in dry conditions (Type P6)  
Requirement 
Thickness range (nominal). 
mm Property Test 
method 
 Unit 
 
6 to 13 > 13 to 20 >20 to 25 > 25 to 32 >32 to 40 > 40 
Bending 
strength ISO 16978 N/mm220 
 18 16 15 14 12 
Modulus of elasticity in bending ISO 16978 N/mm23 150 3 000 2 550 2 400 2 200 2 050 
Internal bond ISO 16984 N/mm20,60 0,50 0,40 0,35 
 0,30 
 0,25 
 
Swelling in thickness, 24 h ISO 16983 % 15 
 14 
 14 
 14 
 13 
 13 
 
NOTE  The values for bending properties, internal bond and swelling in thickness are characterised by a moisture 
content in the material (before treatment in the case of swelling in thickness) corresponding to a relative humidity of 65 % 
and a temperature of 20 °C. If it is made known by the purchaser that the boards are intended for specific use in flooring, 
walls or roofing the performance standard EN 12871 also has to be consulted. This might result in additional requirements 
having to be complied withUS 839:2009 
9 
 4.8 Requirements for heavy duty load-bear ing boards for use in humid conditions 
(Type P7) 
4.8.1 Boards of this type shall comply with t he requirements given in tables 1, 10 and 11. 
Table 10 — Requirements for specified mechanical and swelling properties for heavy duty load-
bearing boards for use in humid conditions (Type P7)  
Requirement 
Thickness range (nominal). 
mm Property Testme
thod Unit 
6 to 13 > 13 to 20 >20 to 25 > 25 to 32 >32 to 40 > 40 
Bending 
strength ISO 
16978 N/mm
222 
 20 18,5 17 16  15 
Modulus of elasticity in bending ISO 16978 N/mm
23 350 3 100 2 900 2 800 2 600 2 400 
Internal bond ISO 
16984 N/mm
20,75 
 0,70 
 0,65 0,60 
 0,55 
 0,50 
Swelling in thickness, 24 h ISO 16983 % 9 
 8 
 8 
 8 
 7 
 7 
 
NOTE  The values for bending properties, internal bond and swelling in thickness are characterised by a moisture 
content in the material (before treatment in the case of swelling in thickness) corresponding to a relative humidity of 65 % and a temperature of 20 °C.If it is made known by the purchaser  that the boards are intended for specific  use in flooring, 
walls or roofing the performance standard EN 12871 also has to be consulted. This might result in additional requirements 
having to be complied with
.
 
 
4.8.2 Requirements for moisture resistance, and if applicable swelling, are dependent upon the test 
method employed to assess these properties. Thus, two al ternative sets of requirements (Option 1 and Option 
2) are set out in table 11 corresponding to the two pr incipal recognised methods of evaluation. It is necessary 
for the manufacturer to show compliance with only one of these two options. 
 
Option 1 requirements apply to boards subjected to an accelerated ageing test, the so-called "cyclic test in 
humid conditions" described in ISO 16987. Option 2 r equirements apply to boards subjected to the so-called 
"boil test" described in ISO 16998. The glues or adhesiv e systems suitable for the application of Option 1 and 
Option 2 are unrestricted. 
 
The alkali content of boards shall not exceed 2.0 %,  based on oven-dry mass and total thickness (tested 
analytically) and shall not exceed 1.7 % in the outer layers (by calculation). 
 
When verifying compliance by external control only th e test option performed and notified by the manufacturer 
shall be carried out. If the option is unknown it will be ne cessary to carry out both se ts of procedures, even 
though compliance is required with only one set of requirements. US 839: 2009 
10 
 Table 11 — Requirements for moisture resistance for heavy duty load-bearing boards for use in humid 
conditions (Type P7) 
Requirement 
Thickness range (nominal). 
mm Property Testmet
hod 
 Unit 
 
6 to 13 > 13 to 20 >20 to 25 > 25 to 32 >32 to 40 > 40 
 
N/mm2 
0.41  
0.36  
0.33  
0.28  
0.25  
0.20 OPTION 1 
Internal bond after 
cyclic test 
 
Swelling in thickness after cyclic test  
ISO 
16987 
 
 
ISO 
16987  
 
 
%  
 
 
11  
 
 
11  
 
 
10  
 
 
9  
 
 
8  
 
 
8 
OPTION 2 
Internal bond after boil test  
ISO 
16998  
N/mm2 
0.25  
0.23  
0.20  
0.18  
0.17  
0.15 
NOTE  The values for internal bond and swelling in thickness after option 1 treatment are characterised by a 
moisture content in the material (before and after cyclic  test) corresponding to a relative humidity of 65 % and a 
temperature of 20 °C. The values for internal bond after option 2 treatment are characterised by a moisture content in the 
material (before the boil test) corresponding to a re lative humidity of 65 % and a temperature of 20 °C.
 
4.9 Supplementary properties 
For certain applications, information on some of the pr operties listed in Table 12 may be required. On request, 
this information shall be supplied by the board manufact urer and in this case shall have been derived using 
the test methods listed in Table 12. 
Table 12 — Supplementary properties and test methods 
Property Test method 
Density US ISO 9427 
Dimensional changes ISO 16985 
Surface soundness ISO 16981 
Swelling in thickness ISO 16983 
Sand content ISO 3340 
 
NOTE  For certain applications, information on additional prop erties not specified in Table 12 may be required. For 
instance, information on thermal conductivity, water vapour permeability and fire behaviour of particleboards is given in 
*US 881. 
5 Verification of compliance 
5.1 General 
Verification of compliance with this Uganda standard shall be carried out using the test methods listed in 
tables 1 to 12. 
5.2 External control 
External control of the factory, if any, shall be carried out according to *US 879-2.  US 839:2009 
11 
 Inspection of isolated lots shall be carried out according to *US 879-2. 
In the case of formaldehyde potential determined by *US 878 perforator method, however, for both external 
control and inspection of isolated lots of panels, the respective requirements set out in Table 1 shall be the 
arithmetic mean value of at least three boards. Additionally, no individual board shall exceed an upper tolerance limit of + 10 %. 
5.3 Factory production control 
Factory production control shall be carried out according to  *US 879-2. The properties listed in the tables 1 to 
11, shall be controlled using intervals between tests not exceeding the intervals given in Table 13. Sampling 
shall be carried out at random. Alternative test methods and/or unconditioned test pieces may be used if a valid correlation to the specified test  methods can be proven (see *US 879-2). 
Each requirement relating to formaldehyde potential (perforator value) shall be met by the 95 percentile value based on test values of individual boards. The 95 percentile  value shall be equal to or less than the respective 
tabulated values given in table 1. 
Table 13 — Maximum intervals between tests for each production line 
Property Maximum interval between tests 
Moisture content 8 h per type of board 
Formaldehyde potentiala)
 Class E 1 
 Class E 2  
24 h per type of board 
1 week per type of board 
All other properties listed in Table 1 8 h per type and thickness range 
Moisture resistance 
 Option 1 
 Option 2  
1 week 
8 hb)
All other properties listed in tables 2 to 11 8 hb)
a) Certain types of particleboards are known to release little or  no formaldehyde. In these case s, the test intervals may be 
increased. However, it remains the resp onsibility of the manufacturer or inspection agency, if any, to ensure compliance 
with this European Standard. 
b) If several thickness ranges are produced in one 8 h shift, the internal control sha ll be organised so that at least one 
board of each thickness range is tested in one week’s production 
6 Marking 
Each panel or package shall be clearly marked by the manufac turer by indelible direct printing with at least the 
following information in this sequence: 
a) the manufacturer's name, trade mark, or identification mark; 
b) the number of this Uganda standard US 839; 
c) the panel type, for example, P5; 
d) the nominal thickness; 
e) the formaldehyde class; and 
f) the batch number, or the production week and year. 
Additionally, panels may be colour coded by the vertical application near one corner of a series of colour 
stripes each 25 mm in width. Colour coding is voluntary.  If applied, it shall comply with the system shown in US 839: 2009 
12 
 Annex A. This standard does not exclude the dyeing of the whole board or  of certain layers of the board 
according to traditional national practices. US 839:2009 
13 
 Annex A 
(normative) 
 
Voluntary colour coding system for particleboards 
Two colours are used in each case. The first colour defines the panel as either intended for general purpose 
use or for load bearing applications (either one or two stripes of this colour are used). The second colour 
identifies the panel as being suitable for use in either dry or humid conditions. 
The colour used are as follows: 
First colour -white: General purpose; 
First colour -yellow: Load-bearing; 
Second colour -blue: Dry conditions; and 
Second colour -green: Humid conditions. 
Table A.1 — Colour coding for particleboards complying with Uganda Standards 
Specification Colour code Board type 
General purpose use, dry white, white, blue P1 
Interior fitments white P2 
Interior fitments white P3 
Load-bearing yellow P4 
Load-bearing yellow P5 
Heavy duty load-bearing yellow P6 
Heavy duty load-bearing yellow P7 
 US 839: 2009 
14 
 Bibliography 
[1] EN 300, Oriented Strand Boards (OSB) — Definitions, classification and specifications 
[2] EN 309, Wood particleboards — Definition and classification 
[3] EN 335-3, Durability of wood and wood-based products — Definition of hazard classes of biological 
attack — Part 3: Application to wood-based panels 
[4] EN 789, Timber structures — Test methods — Determi nation of mechanical properties of wood-based 
panels 
[5] EN 1058, Wood based panels - Determination of characteristics values of mechanical properties and 
density 
[6] ENV 1156, Wood-based panels — Determination of duration of load and creep factors 
[7] ENV 1995-1-1, Eurocode 5 — Design of timber structures — Part 1-1: General rules and rules for 
buildings 
[8] EN 12369-1, Wood-based panels — Characteristic values for structural design — Part 1: OSB, 
particleboards, and fibreboards 
 US 839: 2009 
 Certification marking 
Products that conform to Uganda standards may be  marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licens ed under the certification ma rk scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control a nd testing in accordance with the 
certification mark scheme of the Uganda Nationa l Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 US 839: 2009 
 
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