KENYA STANDARD       KS 2835 : 2018 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
Concrete paving flags — Requirements 
and test methods  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ©KEBS 20 18        First Edition  2018 
 
 
 
 KS 2835: 2018  
 ii  
TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
 1. Architectural Association of  Kenya  
2. Bamburi Cement  
3. CHRYSO Eastern Africa Limited  
4. Concrete Products (K)Ltd  
5. Consumer Information Network  
6. Howards Humpreys East Africa LTD  
7. Institute of quantity surveyors of Kenya  
8. Kenya Industrial Research and Development Institute (KIRDI  
9. Kenya Institute of Highways and Building Technology (KIHBT)  
10. Ministry of Transport, Infrastructure, Housing and  Urban Development.  
11. National Environment Management Authority  
12. National Housing Corporation  
13. Technical University of Kenya  
14. University of Nairobi  
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, 2018 
 
Copyright: Users are reminded that by virtue of section 6 of the Copyright Act, Cap. 130 of the Laws of Kenya, copyright subsists in all 
Kenya Standards and except as provided under section 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 
Managing Director . 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
©KEBS 201 8 — All rights reserved   iii     
 
 
 
 
 
 
 
 
 
 
 
KENYA STANDARD        KS 1933: 20 17 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Concrete paving flags — Requirements and 
test methods  
 
 
 
 
 
 
 
 
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  
 
 KS 2835: 2018  
 iv  
Foreword  
 
This Kenya Standard was prepared by the Concrete and Concrete Products Technical Committee under the 
guidance of the Standards Projects Committee and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
  
 
During the preparation of this standard, reference was made to the following publications:  
 
BS EN 1339:2003 Concrete paving flags. Requirements and test methods  
 
Acknowledgement is hereby made for the assistance derived from these sources.   
©KEBS 201 8 — All rights reserved   5     
KENYA STANDARD       KS 2835: 2018  
 
Concrete paving flags — Requirements and test methods  
 
1. Scope  
 
This Standard specifies materials, properties, requirements and test methods for cement bound  
unreinforced concrete paving flags and complementary fittings.  
 
It is applicable to precast concrete paving flags and complementary fittings that are for use in 
trafficked  paved areas an d roof coverings.  
 
In case of regular use of studded tyres additional requirements are sometimes needed.  
 
This standard does not deal with the tactility or visibility of flags nor with permeable flags.  
 
This standard provides for the product marking and th e evaluation of conformity of the product to 
this Standard.  
 
2.  Normative references  
This Standard incorporates by dated and undated references, provisions from other publications. 
These normative references are cited at the appropriate places in the text, and the publications 
are listed hereafter. For dated references subsequent amendments to or revisions of any of these 
publications apply to this European Standard only when incorporated in it by amendment or 
revision. For undated references, the latest edi tion of the publication referred to applies (including 
amendments).  
 
EN 10083 -2, Quenched and tempered steels — Part 2: Technical delivery conditions for unalloyed 
quality steels.  
 
EN 13369, Common rules for precast concrete products.  
 
ISO 4288, Geometric product specification (GPS) - Surface texture - Profile method: Rules and 
procedures for the assessment of surface texture (ISO 4288:1996).  
 
ISO 6506 -1, Metallic materials - Brinell hardness test - Part 1: Test method.  
 
ISO 6506 -2, Metallic materials - Brinell hardness test - Part 2: Verification and calibration of 
testing machines.  
 
ISO 6506 -3, Metallic materials - Brinell hardness test - Part 3: Calibration of reference blocks.  
 
ISO 48, Rubber, vulcanised or thermoplastic — Determination of hardness (hard ness between 10 
IRHD and 100 IRHD).  
 
ISO 4662, Rubber — Determination of rebound resilience of vulcanizates.  
 
ISO 7619, Rubber — Determination of indentation hardness by means of pocket hardness meters.  
 
ISO 7873, Control charts for arithmetic average with  warning limits.  KS 2835: 2018  
 6  
ISO 7966, Acceptance control charts.  
 
ISO 8486 -1, Bond abrasives — Determination and designation of grainsize distribution — 
Macrogrits F4 to F220.  
 
3. Terms and definitions  
For the purposes of this Standard, the following terms and definitions apply.  
 
3.1.  
arris  
part of a flag where two faces meet. It can be bevelled, rounded, chamfered, radiussed or splayed  
 
3.2.  
concrete paving flag  
precast concrete unit used as a surfacing material that satisfies the following conditions:  
 
⎯ its overall length does not exceed 1 m;  
 
⎯ its overall length divided by its thickness is greater than four  
 
NOTE These two conditions are not applicable to complementary fittings.  
 
3.3.  
complementary fitting  
unit, sometimes a part of a flag, which is used to infill and enable an area to be completely 
surfaced  
 
3.4.  
permeable paving flag  
flag intended, by its structure, to allow the passage of water through the flag  
 
3.5.  
overall length  
longer side of the rectangle with the smallest area able to enclose the flag exclud ing any spacer 
nibs 
 
3.6.  
overall width  
shorter side of the rectangle with the smallest area able to enclose the flag excluding any spacer 
nibs 
 
3.7.  
thickness  
distance between the upper face and the bed face of the flag  
 
3.8.  
spacer nibs  
small  protruding profiles on a side face of a flag  
 
3.9.  
upper face  
surface intended to be seen when in use   
©KEBS 201 8 — All rights reserved   7     
3.10.   
bed face  
surface generally parallel to the upper face and in contact with the bedding after laying  
 
3.11.   
facing layer  
layer  of concrete on the upper face of a flag of different material and/or properties to the main 
body or  
backing layer of a flag  
 
NOTE To be distinguished from wipe, being a fine cement mortar or slurry applied to the surface of the flag.  
 
3.12.   
draw  
intended angle  of the side face from the vertical plane over the full height of a flag as shown in 
Figure 1  
 
Key 
1 Chamfer   2 Thickness   α Draw  
Figure 1 — Example of chamfer and draw  
 
3.13.   
chamfer  
bevelled arris, as shown in Figure 1  
 
3.14.   
work dimension  
any dimension of a flag specified for its manufacture to which the actual dimension should 
conform within  specified permissible deviations  
 
3.15.   
secondary processing  
manufacturing process to texture the whole flag or any surface, carried out after basic 
manufactu re before  or after hardening  
 
3.16.   
actual dimension  
dimension of a flag as measured  
 
3.17.   
chased side face  
side face of a concrete paving flag, having a recessed profile  
 
3.18.   
skid resistance  
KS 2835: 2018  
 8 ability to resist relative movement between a vehicle tyre and the trafficke d concrete paving flag 
surface  
 
3.19.   
slip resistance  
ability to resist relative movement between a pedestrian foot and the trafficked concrete paving 
flag surface  
 
3.20.   
format  
work  dimensions of a flag specified in order of overall length, overall width and thickness  
 
3.21.   
wipe  
fine cement mortar or slurry applied to the surface of the units  
 
 
4.  Requirements for materials  
 
4.1.  General  
Only materials with suitability established in terms of their properties and performance shall be 
used in the manufacture of concrete paving flags. The suitability requirements of the materials 
used shall be given in the manufacturer’s production control documentation.  
 
Where, by conformity with relevant specif ications, the properties and performance of materials 
have been  demonstrated, further testing need not be performed.  
 
A reference scheme for materials inspection is given in annex A.  
 
4.2. Asbestos  
Asbestos, or materials containing asbestos, shall not be used.  
 
5. Requirements for products  
 
5.1. General  
The performance requirements of concrete paving flags are defined by classes which have 
associated  marking designations.  
 
Flags may be produced with a single concrete throughout or with different facing and backing 
layer s. When flags are produced with a facing layer this shall have a minimum thickness of 4 mm 
over that area  claimed by the manufacturer to be faced, when measured in accordance with 
annex C. Isolated particles of aggregate protruding into the facing layer sh all be ignored. The 
facing layer shall be an integral part of the flag.  
 
An arris described as square may be bevelled or rounded. The horizontal or vertical dimensions 
shall not  exceed 2 mm.  
 
A bevelled arris exceeding 2 mm shall be described as chamfered.  Its dimensions shall be 
declared by the manufacturer.  
 
Flags may be produced with functional and/or decorative profiles, which shall not be included in 
the work  dimensions of a flag.  
  
©KEBS 201 8 — All rights reserved   9    The surface of flags may be textured, secondary processed or treated ch emically; these finishes 
or treatments shall be described and declared by the manufacturer.  
 
5.2. Shape and dimensions  
 
5.2.1.  General  
All references to dimensions in this subclause are to work dimensions.  
 
The conformity criteria corresponding to each requirement taken separately are given in 6.3.8.1. 
The dimensions and deviations shall be measured according to annex C.  
 
5.2.2.  Work dimensions  
The work dimensions shall be stated by the manufacturer.  
 
5.2.3.  Spacer nibs, draw or chased profiled side faces  
Flags may be produced wi th spacer nibs, a draw or chased profiled side faces. When these are 
provided,  
the manufacturer shall declare their work dimensions.  
 
; 
 
5.2.4.  Permissible deviations  
The permissible deviations on the manufacturer's declared work dimensions are given in Tables 1,  
2 and 3.  
 
Table 1 — Permissible deviations  
Class  Marking  Flag work  
dimensions  
mm Length  
mm Width  
mm Thickness  
mm 
1 N all ±5 ±5 ±3 
2 P ≤600 ±2 ±2 ±3 
  ˃600 ±3 ±3 ±3 
3 R all ±2 ±2 ±2 
The difference between any two measurements of the length, width and thickness of a single flag 
shall be ≤ 3 mm.  
 
 
For non -rectangular flags the deviations of the other dimensions shall be declared by the 
manufacturer. When the length of the diagonals exc eeds 300 mm, the maximum permissible 
differences between the measurement of the two diagonals of a rectangular flag are given in 
Table 2.  
 
Table 2 — Maximum differences between the measurement of the diagonals  
Class  Marking  Diagonal  
mm Maximum difference  
mm 
1 J ≤ 850 5 
  > 850  8 
2 K ≤ 850 3 
  > 850  6 
3 L ≤ 850 2 
  > 850  4  KS 2835: 2018  
 10  
When the maximum dimension of a flag exceeds 300 mm, the deviations for flatness and bow 
given in Table 3 shall apply to an upper face intended to be plane.  
 
When the upper face is not intended to be plane, the manufacturer shall supply the information on 
deviations.  
Table 3 — Deviations of flatness and bow  
Length of gauge  
mm Maximum convex  
mm Maximum concave  
mm 
300 1.5 1.0 
400 2.0 1.5 
500 2.5 1.5 
800 4.0 2.5 
 
5.3.  Physical and mechanical properties  
 
5.3.1.  General  
The flags shall conform to the following requirements at the time they are declared suitable for use 
by the  manufacturer.  
 
When complementary fittings cannot be tested according to this standard, they are considered to 
conform to this standard, provided they have at least the same concrete quality as flags complying 
with this standard.  
 
5.3.2.  Weathering resistance  
 
5.3.2.1.  Test method  
The weathering resistance is determined by tests annex D for water absorption and to the 
conformity criteria of 6.3.8.2.  
 
5.3.2.2.  Performance and classes  
The flags shall conform to the requirements in Table 4.  
 
 
Table 4— Water absorption  
Class  Marking  Water absorption  
% by mass  
1 A no performance 
measured  2 B ≤6 
 
 
5.3.3.  Bending strength  
 
5.3.3.1.  Test method  
The characteristic bending strength shall be determined by testing according to annex D and to 
the conformity criteria given in 6.3.8.3.  
 
5.3.3.2.  Performance and classes  
The characteristic bending strength shall not be less than the value corresponding to the class in 
Table 5.  
 
None of the individual results shall be less than the corresponding minimum bending strength in 
Table 5.   
©KEBS 201 8 — All rights reserved   11    Table 5 — Bending strength classes  
Class  Marking  Characteristic bending 
strength  
MPa Minimum bending strength  
MPa 
1 S 3.5 2.8 
2 T 4.0 3.2 
3 U 5.0 4.0 
 
Guidance on application may be provided at a national level.  
 
5.3.3.3.  Complementary fittings  
Complementary fittings are not to be tested but considered to be in the same class as the 
standard flags,  provided they have at least the same concrete strength.  
 
5.3.3.4.   Durability of strength  
Under normal exposure conditions of use precast concrete flags will continue to provide 
satisfactory strength, provided they conform to 5.3.3.2 and are subject to normal maintenance.  
 
5.3.4.  Abrasion resistance  
 
5.3.4.1.  Test method  
Abrasion resistance is determined by the Wide Wheel Abrasion test (see annex F), or as an 
alternative by the Böhme test (see annex G). The Wide Wheel Abrasion test is the reference test.  
 
5.3.4.2.  Performance and classes  
Requirements for abrasion resistance are given in Table 6. No individual result shall be greater 
than the required value.  
 
Table 6 — Abrasion resistance classes  
Class  Marking  Requirement  
Measured in accordance 
with the  test method 
described in annex F Alternatively measured in 
accordance  
with the test method 
described in  
annex G 
1 
2 
3 
4 F 
G 
H 
I No performance measured  
≤ 26 mm  
≤ 23 mm  
≤ 20 mm  No performance measured  
≤ 26 000 mm3/5 000 mm2 ≤ 
20 000 mm3/5 000 mm2 ≤18 
000 mm3/5 000 mm2 KS 2835: 2018  
 12 5.3.5.  Slip/skid resistance  
 
5.3.5.1.  Conditions  
Concrete paving flags have satisfactory slip/skid resistance provided that their whole upper 
surface has not been ground and/or polished to produce a very smooth surface.  
 
5.3.5.2.  Test method  
If in an exceptional case a value for slip/skid resistance is required, the test method as described 
in annex H shall be used and the minimum slip/skid resistance value shall be declared.  
 
If the surface of a flag contains ridges, grooves or other surface features which prevent testing by 
the pendulum friction equipment, the product is deemed to satisfy the requirements of this 
standard without testing. Where the flag is too small to provide a test area, the manufacturer shall 
test a larger flag having the same surface finish as the flag in question.  
 
NOTE The slip/skid resistance value relates to flags as manufactured and helps to ensure adequate slip/skid resistance on 
installation.  
 
5.3.5.3.  Durability of slip/skid resistance  
Under normal conditions of use precast  concrete flags provide satisfactory slip/skid resistance 
during the  working life of the product, provided they are subjected to normal maintenance and 
unless a major proportion of aggregates which polish excessively have been exposed on the 
upper face.  
 
5.3.6.  Breaking load  
 
5.3.6.1.  Test method  
 
The breaking load shall be determined in accordance with the test method described in annex E. 
The conformity criteria are given in 6.3.8.2.  
 
5.3.6.2.  Performance and classes  
The flags shall conform to the values indicated in Table 7.  
 
Table 7 — Breaking load classes  
Class  
number  Marking  Characteristic breaking load  
KN Minimum breaking load  
kN 
30 3 3.0 2.4 
45 4 4.5 3.6 
70 7 7.0 5.6 
110 11 11.0 8.8 
140 14 14.0 11.2 
250 25 25.0 20.0 
300 30 30.0 24.0 
NOTE For design considerations special attention should be given to the possible loading conditions on flags  
larger than 600 mm.  
 
 
5.3.7.  Fire performance  
 
5.3.7.1.  Reaction to fire  
Concrete paving flags are Class A1 reaction to fire without testing.  
 
5.3.7.2.  External fire performance   
©KEBS 201 8 — All rights reserved   13    Concrete  paving flags used as roof covering are deemed to satisfy the requirements for external 
fire performance without the need for testing.  
 
5.3.8.  Thermal conductivity  
If concrete flags are intended to contribute to the thermal performance of an element, then the 
manufacturer shall declare the thermal conductivity using design data from EN 13369.  
 
 
5.4. Visual aspects  
 
5.4.1.  Appearance  
The upper faces of the concrete flags shall not exhibit defects such as cracking, or flaking, when 
examined in accordance with annex I. 
 
In the case of two -layer flags and when examined in accordance with annex I there shall be no 
delamination (i.e. separation) between the layers.  
 
NOTE When efflorescence occurs it is not deleterious to the performance of the flags in use and is not conside red 
significant.  
 
5.4.2.  Texture  
In the case of flags produced with special surface textures, the texture shall be described by the 
manufacturer.  
 
If examined in accordance with annex I, conformity shall be established if there are no significant 
differences in t exture to any samples supplied by the manufacturer and approved by the 
purchaser.  
 
NOTE Variations in the texture consistency of the flags can be caused by unavoidable variations in the properties of the 
raw materials and by variations in hardening and are  not considered significant.  
 
5.4.3.  Colour  
Colours may be provided in a facing layer or throughout the flag at the manufacturer's discretion.  
 
If examined in accordance with annex I, conformity shall be established if there are no significant 
differences in colo ur to any samples supplied by the manufacturer and approved by the 
purchaser.  
 
NOTE Variations in the colour  consistency of the flags can be caused by unavoidable variations in the shade and 
properties of the raw materials and by variations in hardening and are not considered significant.  
 
6. Evaluation of conformity  
 
6.1. General  
 
For the purpose of testing, the manufa cturer may group products into families, where it is 
considered that the value of a selected property is common to all products within that family. Such 
families are:  
 
1) strength family: flags manufactured using the same type of materials and production m ethods, 
irrespective of dimensions and colours;  
 
NOTE Breaking load is dependent upon flag dimensions  
 
2) surface family: flags with face mixes having the same main aggregate used in the mix (e.g. 
natural river gravel, crushed granite, porphyr, basalt or l imestone) and the same surface treatment 
of the finished product, irrespective of dimensions and colours.  
 
 
 KS 2835: 2018  
 14 6.1.1.  Demonstration of conformity  
Conformity of the product with the requirements of this standard and with the declared values 
(levels or  classes) for t he product properties shall be demonstrated by carrying out both:  
 
⎯ type testing of the product (see 6.2);  
 
⎯ factory production control (see 6.3), including product testing.  
 
6.1.2.  Assessment of conformity  
In addition, conformity of the product with this standard may be assessed:  
 
⎯ either by a third party inspecting the manufacturer’s type testing and factory production control  
procedures;  
 
⎯ or by acceptance testing of a consignment at delivery (e.g. in the case of dispute, see annex B).  
 
6.2. Type testing of  the product  
 
6.2.1.  Initial type testing  
Initial type testing shall be performed to demonstrate conformity with this standard at the 
beginning of the  manufacture of a new product type or a family of product types, or setting up a 
new production line, to confirm that the achieved properties of the product meet the requirements 
of this standard and the values  declared for it by the manufacturer.  
 
Where the product has previously been tested according to this standard, (same product, same 
characteristics, same or mo re demanding test method and same sampling procedure), the result 
may be  used to satisfy initial type testing.  
 
6.2.2.  Further type testing  
Whenever a change occurs in the raw materials, the proportions used or the production 
equipment or process, which would change significantly some or all of the properties of the 
finished product, the type tests shall be repeated for the selected property or properties.  
 
NOTE Examples of major changes:  
 
1) change from natural river gravel to crushed rock aggregates or change  of cement type or class;  
 
2) partial substitution of cement by additions.  
 
For abrasion and weathering resistance, type testing shall be repeated periodically with the 
frequency given in Table 8 even when no change occurs.  
Table 8 — Periodically repeated type testing  
 Property  Frequency    
 Abrasion (only classes 2, 3 and 4)  Once per year per surface family    
 Weathering resistance (only class 3)  Once per year per surface family')   
      1J If for a surface family the result of a type test (mass loss) is lower than 50 % of the required value 
the test frequency may be reduced to once per two years. 
If for a surface family, routine water absorption testing at the frequency for class 2 product s (see 
6.3.8.2.) is carried out to demonstrate consistency with flags submitted to freeze thaw testing, the 
required test frequency may be reduced to once per two years.  
 If both conditions are met, the test frequency may be reduced to once per four years.    
       
©KEBS 201 8 — All rights reserved   15     
6.2.3.  Sampling, testing and conformity criteria  
The number of flags to be tested shall be in accordance with Table 9 for the selected property.  
Table 9 — Sampling plan and conformity criteria for initial and further type testing  
 
Property  Requirement  Testing  
method  Number of 
flags  Conformity criteria  
 
Visual aspects  5.4 Annex I  101) No flag shall show cracking, flaking or 
delamination 21 
Thickness of 
facing layer  5.1 C.62) 8 Each flag shall meet the 
requirements  
Shape and  
dimensions  5.2 Annex C 2) 81) Each flag shall meet the 
requirements for the declared class  
Bending strength  5.3.3 -Table 5  Annex E 8 No flag shall have a bending  
strength less than the characteristic 
value for the declared class  
Breaking load  5.3.6 - Table 7  No flag shall have a breaking load 
less than the characteristic value for 
the declared class  
Abrasion  
resistance  (only  
classes 2, 3 and 
4) 5.3.4  Annex F or G 3 Each  flag shall meet  the 
requirements for the declared class  
Slip/skid  
resistance  (only  
where tested)  5.3.5  Annex H 5 The mean of the five flags shall be 
declared  
Weathering 
— class 2  
 5.3.2  
 Annex D  
 3  
 No flags  shall have  a water  
absorption  greater than  6 % by  
mass  
 
1) These flags may be used for subsequent tests  
2) C.6 only applies to flags with  a facing layer  
be used for subsequent tests.  
flags with a facing layer.   
 
The type tests shall be carried out in accordance with the reference test methods called up in thus 
standard.  
 
Type testing is normally carried out with the manufacturers test equipment  
 
The test results shall be recorded.  
 
6.3. Factory production control  KS 2835: 2018  
 16  
6.3.1.  General  
The manufacturer shall establish, document and maintain a factory production control system to 
ensure that the products placed on the market will conform with the specified or declared values.  
 
The factory production control system shall consist of procedu res, regular inspection and tests 
and the utilisation of the results to control raw and other incoming materials, equipment, the 
production process and the product.  
 
An example of a suitable inspection scheme for factory production control is given in anne x A. 
The results of inspections requiring action and the results of tests shall be recorded.  
 
The action to be taken when control values or criteria are not met shall be given.  
 
6.3.2.  Equipment  
All weighing, measuring and testing equipment shall be calibrated an d regularly inspected 
according to the ndocumented procedures, frequencies and criteria.  
 
An inspection scheme for equipment is given in A.1.  
 
6.3.3.  Raw and other incoming materials  
The specifications of all incoming materials shall be documented.  
 
An example of an inspection scheme for raw materials is given in A.2.  
 
6.3.4.  Production process  
The relevant features of the plant and production process shall be defined giving the frequency of 
the inspection checks and tests, together with the criteria required both on equi pment and on work 
in progress.  
 
An example of an inspection scheme for the production process is given in A.3.  
 
6.3.5.  Product testing  
A sampling and testing plan of products shall be prepared and implemented.  
 
The sample shall be representative of production.  
 
The tests shall be carried out in accordance with the methods called up in this standard or by 
applying  alternative test methods with a proven correlation to the standard methods.  
 
The results of testing shall meet the specified conformity criteria (see 6. 3.8) and be recorded.  
 
An example of an inspection scheme for product testing is given in A.4.1.  
 
Switching rules for product testing are given in A.5.  
 
6.3.6.  Marking, storage and delivery of products  
 
The marking, storage and delivery control, together with pro cedures for dealing with non -
conforming  products (see 6.3.7) shall be documented.  
 
Products may be released before the final results of factory production control testing are 
received, if they  are subject to a positive recall procedure.  
 
An example of an i nspection scheme for marking, storage and delivery is given in A.4.2.  
 
6.3.7.  Non-conforming products   
©KEBS 201 8 — All rights reserved   17    If the results of the tests on a product are unsatisfactory, the manufacturer shall take the 
necessary steps in order to rectify the shortcoming.  
 
Products which  do not conform to the requirements shall be set aside and marked accordingly.  
 
If any non -conformity of the product is established after delivery, the customer shall be notified.  
 
6.3.8.  Product conformity criteria  
When the conformity criteria in this clause may  be considered either by attributes or variables, the 
method  applied shall be at the manufacturer's discretion.  
 
6.3.8.1.  Shape and dimensions  
 
A. Attributes  
 
The conformity of the production with 5.2 shall be assessed for each production line per one to 
four producti on days depending on the work dimensions of the flags and the needs of delivery 
(see sampling  according to A.4.1.3). Each of the requirements in 5.2 shall be considered 
separately.  
 
a) If the sample consists of less than eight flags (see switching rules in  A.5) and each of the 
requirements  in 5.2 is complied with by all of the flags, then the sample and the corresponding 
production shall be accepted. If not, this sample shall be increased to eight flags and the 
procedure given in b) shall apply.  
 
b) If the sample consists of eight flags and not more than one of the flags does not conform to any 
one of  the requirements in 5.2 considered separately for the declared class, the sample and the 
corresponding production shall be accepted. If not, this sample shall be increased to 16 flags and 
the procedure given in c) shall be applied.  
 
c) If the sample consists of 16 flags and not more than two of the flags do not conform to any one 
of the requirements in 5.2 considered separately for the declared class,  the sample and the 
corresponding production shall be accepted. If more than two of the flags do not conform to any 
one of the requirements considered separately, the sample and the corresponding production are 
not accepted and 6.3.7 applies.  
 
B. Variables  
 
When the standard deviation of a production line is known and regularly checked, the conformity 
of the production with 5.2 shall be assessed for each production line per day or consecutive 
production days not  exceeding five (see sampling according to A.4.1 .3). Each of the requirements 
in 5.2 shall be considered  separately.  
 
The conformity is assessed on a 10 % fractile.  
 
The acceptability of the samples considered shall be checked using a control chart conforming to 
either ISO 7966 or ISO 7873 and taking in to account 5.2, provided the probability of acceptance is 
equivalent to that resulting from testing by attributes.  
 
If the sample and the corresponding production are not accepted, 6.3.7 applies.  
 
6.3.8.2.  Weathering resistance (class 2 - water absorption)  
The conf ormity of the production with 5.3.2 (class 2) shall be assessed for each family and each 
five production days, or more according to the switching rules (see sampling according to A.4.1.7).  
 
a) If the sample consists of three or six flags (see switching rules in A.5) and the 
requirements in 5.3.2 (class 2) are complied with, the sample and the corresponding KS 2835: 2018  
 18 production shall be accepted. If not, this sample shall be increased to nine flags and the  
procedure given in b) shall apply.  
 
b) If the sample consists of nine flags and the sample complies with the requirements in 
5.3.2 (class 2) , the sample and the corresponding production shall be accepted. If not, the 
sample and the  corresponding production a re not accepted and 6.3.7 applies.  
 
6.3.8.3.  Bending strength and breaking load  
 
A. Attributes  
The conformity of the production with 5.3.3 and 5.3.6 shall be assessed for each production line 
per one to four production days depending on the work dimensions of the f lags, the needs of 
delivery and the breaking load (see sampling according to A.4.1.5 and A.4.1.6).  
 
a) If the sample consists of eight flags or fewer (see switching rules in A.5) and the strength T and 
the breaking load of each of the flags is not lower th an the characteristic value of Tables 5 and 7 
for the declared classes, the sample and the corresponding production shall be accepted. If not, 
this sample shall be increased to 16 flags and the procedure given in b) shall apply.  
 
b) If the sample consists of 16 flags and the strength T and the breaking load of not more than one 
of the  flags is lower than the characteristic value of Tables 5 and 7 for the declared classes but not 
lower than the minimum value of Tables 5 and 7 for the declared classes, the sa mple and the 
corresponding production shall be accepted. If not, the sample and the corresponding production 
are not accepted and 6.3.7 applies.  
 
B. Variables  
When the standard deviation for a production line is known and regularly checked, the conformity 
of the  production with 5.3.3 and 5.3.6 shall be assessed for each production line per production 
day or consecutive production days not exceeding five (see sampling according to A.4).  
 
The conformity is assessed on a 5 % fractile.  
 
The acceptability of the  samples considered shall be checked using a control chart complying 
either with  ISO 7966 or ISO 7873 and taking into account 5.3.3 and 5.3.6, provided the probability 
of acceptance is equivalent to that resulting from assessment by attributes (see annex J). 
 
If the sample and the corresponding production are not accepted, 6.3.7 applies.  
 
6.3.8.4.  Visual aspects  
The conformity of the production with 5.4 shall be assessed in case of doubt (see sampling 
according to  A.4.1.2) The sample tested shall satisfy the require ments of the standard. If not, the 
sample and the corresponding production are not accepted and 6.3.7 applies.  
 
 
7. Marking  
 
The following particulars relating to flags shall be supplied:   
©KEBS 201 8 — All rights reserved   19    1: On the delivery note or on the invoice or on the manufacturer’s declaration.  
 
2: On 0 .5 % of the flags with a minimum of one marking per package or on the packaging itself if 
not reused.  
 
Classes and their identification:  
 
Requirement      Marking  
weathering resistance    A, B or D  
abrasion resistance    F, G, H or I  
Diagonals      J, K or L (where relevant)  
Dimensions     N, P or R  
bending strength     S, T or U  
breaking load     3, 4, 7, 11, 14, 25 or 30  
 
Where ZA.3 covers the same information as this clause 7, the requirements of this clause are met 
for CE  marked prod ucts.  
 
8. Test report  
The following particulars shall be supplied in the test report (other than for tests for factory 
production  control):  
 
1) the name of the organization  carrying out the test;  
 
2) the name of the person carrying out the test;  
 
3) the  date of the test;  
 
4) the name of the source providing the sample;  
 
5) the sample reference including the date of production;  
 
6) the name of the person taking the sample;  
 
7) the relevant KS number and annex;  
 
8) the name of the test;  
 
KS 2835: 2018  
 20 9) the  test result;  
 
10) any pertinent remarks about the sample or test result.  
 
Annex A  
(informative)  
Inspection schemes  
A.1 Equipment inspection  
Subject  Aim Method  Frequency  
A.1.1 Testing and measuring  equipment  
All testing and measuring 
equipment  Correct functioning and 
accuracy  Where applicable calibrating against 
equipment which has been calibrated traceable 
to national standards and is used exclusively 
for this purpose except as indicated in the 
test method  On (re)installation, after 
major repair or once 
per year  
A.1. Storage  and production equipment  
1 Storage of 
Materials  Absence of 
contamination  Visual inspection or other 
appropriate method  — On installation — 
Weekly  
2 Weighing or 
volumetric 
batching  
equipment  Correct functioning  Visual inspection  Daily 
3 Flag manufacturer's 
declared accuracy  Calibrating against equipment which 
has been calibrated traceable to 
national standards and is used 
exclusively for this purpose  — On (re)installation — 
Weighing: once a year 
Volumetric : twice a year 
 Incase of 
doubt  
 
— In case of doubt  
4 Mixers  Wear and correct 
functioning  Visual inspection  Weekly  
5 Moulds  Cleanliness and 
condition  Visual inspection  Daily  
 A.2 Materials inspection  
Subject  Aim Method  Frequency  
A.2.1 All materials  
1 All materials  To ascertain  that the 
consignment is as ordered and from 
the correct source  Inspection of delivery ticket and/or label on 
the package showing conformity with 
the order  Each delivery  
A.2.2 Materials not submitted to an assessment of conformity before delivery') 
1 Cement  and 
other cementitious 
materials  Conformity  with flag 
manufacturer's requirements  KS EAS 18  Each delivery  
2 aggregates  Conformity  with flag 
manufacturer's  requirements  
 KS 95  
 Each delivery  
3   
 
For example  
 Particle grading  
 Test by sieve analysis  
 — First delivery from new 
source  
— In case of doubt — 
Once per week  
— First delivery from new 
source  
— In case of doubt     Impurities or contamination  Appropriate test method  
4 Admixture  Conformity  w ith normal  
appearance   KS 2670  Each delivery  
5 Density  Flag manufacturer's method  Flag manufacturer’s method  
6 Additions/ 
pigments  Conformity  w ith normal  
appearance   Visual inspection  Each delivery  
 
 
— First use of new 
source  
— water from open 
water course: three times 
a year, or more (depending 
on local conditions)  
— Other sources : 
once a year  
— In case of doubt  7 Density   Flag manufacturer's method  
8 Water  not 
taken  from a  
public distribution 
system  
 Conformity  with flag 
manufacturer's requirements  Testing according to standard  
     
 
9 
10 Recycled water  Check for solid content and other 
contaminants  Visual  Weekly  
Flag manufacturer's method  In case of doubt  
17 Materials not audited by the flag manufacturer or by a third party acceptable to the flag manufacturer. 
 KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  2 A.3 Production process inspection  
Subject  Aim Method  Frequency  
1 Mixture 
composition  Conformity with intended 
composition (weight or 
volumetric batched)  — Visual on weighing equipment  
— Checking  against  production  
process documents  Daily  
2 Conformity with intended 
mixture values (only 
volumetric batched)  Fresh concrete analysis  Monthly  
3 Fresh concrete  Correct mixing  KS 594  Daily for each mixer  
4 Production  Conformity  with 
documented  factory  
procedures  Checking actions against factory 
procedures  Daily  
A.4 Product inspection  
Subject  Aim Method  1 Frequency 1,2,3)  
A.4. Product testing   
1 Visual aspects  See 5.4  Visual check  Daily 
Annex I In case of doubt (sample of ten flags).  
2 
3 Shape and  
dimensions  See 5.2  Annex C  Eight flags per machine and  
— per production day if work length < 300 mm — per 2 
production days if work length  
300 mm and < 600 mm  
— per 4 production days if work length ?_ 600 
mm 
4 Thickness  of 
facing layer  See 5.1  Annex C  As for bending strength  
5 
6 Bending  
strength  
Breaking 
load See 5.3.3 - Table 5  
See 5.3.6 - Table 7  Annex D Eight flags per strength family per machine and — per 
production day if both work length  
and width < 300 mm  
— per 2 production days if both work length and w idth
 300 mm ands 600 mm  
— per 4 production days if both work length and width 
> 600 mm  7 Weathering 
resistance  
(only class 2)  See 5.3.2  Annex D Once per surface family per 5 production days (sample of 
three flags)  
A.4.2 Marking, storage, delivery  
1 Marking  Marking  of product  
according to clause 7  Visual check  Daily 
2 Storage  Segregation of non - 
conforming product  Visual check  Daily KS  2017  
©KEBS 2005 — All rights reserved                3 3 Delivery  Correct delivery age, 
loading and loading 
Documents  Visual check  Daily 
1) Type testing according to 6.2 of this standard not included.  
2) The switching rules apply (see A.5).  
3) See 6.1.  
 
A.5 Switching rules  
A.5.1 Normal inspection  
The rate of sampling should be  in accordance with A.4.1.  
A.5.2 Normal to reduced inspection  
Reduced inspection corresponds to half the rate of normal inspection1). 
It should be used when normal inspection is effective and the preceding 10 successive samples have 
been accepted.  
A supplementary reduced inspection is allowed if the same conditions as above are satisfied under 
reduced inspection.  
This supplementary reduced inspection should correspond to half the rate of the reduced inspection.  
A.5.3 Reduced to normal inspection  
When reduced inspection or supplementary reduced inspection is in effect, normal inspection should be 
reinstated if any of the following occurs.  
— a sample is not accepted;  
— or the production becomes irregular or delayed;  
— or other conditions warrant tha t normal inspection should be instituted.  
A.5.4 Tightened inspection  
Tightened inspection requires the number of units in the sample to be doubled.  
It should be used if during normal inspection two out of five successive samples fail.  
A.5.5 Tightened to  normal inspection  
Tightened inspection should continue until five successive samples are accepted. Then normal inspection 
may be resumed.  
A.5.6 Stopped production  
If production remains on tightened inspection for ten successive samples the production line should be 
deemed to be out of control and stopped. The production system should be reviewed and any necessary 
changes made.  
Having corrected the production system, pr oduction should start again on tightened inspection.  
1) If the number of flags in the sample is even, the reduction should be performed by dividing the number of 
flags by two. In the other cases, the rate of sampling should be reduced by two. 
 
Annex B  KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  4 (normative)  
 
Procedure for acceptance testing of a consignment at delivery  
 
B.1 General  
The sampling procedure and conformity criteria for a consignment at delivery distinguishes two cases:  
— Case I: The product has not been submitted to an assessment of co nformity by a third party (see 6.1.1);  
— Case II: The product has been submitted to an assessment of conformity by a third party.  
 
If case II applies, acceptance testing is not necessary, except in case of dispute (see 6.1.2). The test for 
visual aspects shall be carried out prior to the tests for the other properties. The test shall be performed by 
the purchaser and manufacturer jointly at a location agreed between them, normally the site or factory.  
 
Tests, except for visual aspects, shall be carried out  in a laboratory agreed by the purchaser and the 
manufacturer. They both shall be given a reasonable opportunity to witness the sampling and testing. The  
tests may be carried out with the manufacturer's reliably calibrated test equipment.  
 
In case of dispu te only the contentious property or properties shall be tested.  
 
B.2 Sampling procedure  
 
B.2.1 General  
The required number of flags shall be sampled from each batch of the consignment of flags up to the  
following quantities according to the cases defined i n B.1:  
 
— Case I: 1 000 m2; 
 
— Case II: depending upon the circumstances of the case in dispute, up to 2 000 m2. 
 
However, a partial batch of the consignment shall be added to the previous full batch when the quantity of  
the partial batch is less than half of the quantities given above.  
 
The flags for testing shall be selected as being representative of the consignment and shall be evenly  
distributed through the consignment.  
 
B.2.2 Number of flags to be sampled  
 
The number of  flags to be sampled from each batch shall be in accordance with Table B.1.  
 
B.2.3 Sampling plan  
 
B.2.2 Number of flags to be sampled  
The number of flags to be sampled from each batch shall be in accordance with Table B.1.  
B.2.3 Sampling plan  
Table B.1 — Sampling plan  
Property  Requirement  Testing  
method  Case I  Case II 3) 
Visual aspects  5.4 Annex I 8 1 ) 4 (16)  
Thickness of facing layer  5.1 C.6 2) 8 4 (16)  
Shape and dimensions  5.2 Annex C  8 1)
 4 (16)  
Bending strength  5.3.3 - Table 5  Annex E 8 4 (16)  
Breaking load  5.3.6 - Table 7     KS  2017  
©KEBS 2005 — All rights reserved                5 Abrasion  resistance  (only  
classes 2, 3 and 4)  5.3.4  Annex F or G 3 3 
Slip/skid  resistance  (only  
where tested)  5.3.5  Annex H 5 5 
Weathering resistance      
— class 2  5.3.2  Annex D 3 3 
     
'1)These  flags may be used for subsequent tests.  
2) C.6 only applies for flags with a facing layer.  
3) The number between brackets is the number to be sampled to avoid secondary 
sampling from the  
batch  if, on the basis of the conformity criteria (see B.3.2), additional flags shall be tested 
to assess conformity.  
 
B.3 Conformity criteria  
 
B.3.1 Visual aspects  
When required according to 5.4, the texture and colour  of the sample shall show no significant difference to 
any reference sample supplied by the manufacturer and approved by the purchaser.  
 
No flag of the sample tested shall show cracking or flaking. Flags with a facing layer shall not show  
delaminations.  
 
B.3.2 Other properties  
In case I: the conformity criteria for type testing of Table 9 apply.  
 
In case II: the conformity criteria for attributes of 6.3.8 apply for the properties included. For the other 
properties, the conformity criteria of Table 9 apply.  
 
Annex C  
(normative)  
Measurement of the dimensions of a single flag  
Alternative test methods, e.g. go and no -go gauges, may be used provided at least the same accuracy is 
achieved as in the following test method.  
 
C.1 Preparation  
Remove all flashings and burrs from the flag to be measured.  
 
C.2 Plan dimensions  
 
C.2.1 Apparatus  
Measuring equipment capable of measuring with an accuracy of 0.5 mm.  
 
C.2.2 Procedure  
Measure the relevant work dimensions in two different places for each dimension and record the a ctual 
dimensions obtained to the nearest whole number of millimetres.  
 
For a rectangular flag with a diagonal greater than 300 mm, measure the diagonals and record the difference 
between the two measurements.  
 
C.3 Thickness  
 
C.3.1 Apparatus  
 
Measuring equi pment capable of measuring with an accuracy of 0.5 mm.  KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  6  
C.3.2 Procedure  
Measure the thickness of a flag to the nearest millimetre. Take measurements at four points between 20 and 
30 mm from the edge and within 100 mm from each corner.  
 
Record the four meas urements and calculate the mean thickness to the nearest millimetre. Calculate and  
record the maximum difference between any two readings to the nearest millimetre.  
 
 
C.4 Flatness and bow  
 
C.4.1 Apparatus  
Measuring equipment capable of measuring with an accuracy of 0 .1 mm over the specified length ± 1 mm.  
 
NOTE For example, a notched straight edge and gauge, both made of steel, as shown in Figure C.1.  
 
C.4.2 Procedure  
The maximum convex and concave deviations shall be determined along the two diagonal axe s of the upper 
face to the nearest 0.1 mm. Record both results.  
 
C.5 Chamfer  
 
C.5.1 Apparatus  
 
Measuring equipment capable of measuring with an accuracy of 0.5 mm.  
 
NOTE See example given in Figure C.2.  
 
C.5.2 Procedure  
Make measurements at four positions on a flag, one on each side. Calculate and record the mean vertical  
and horizontal dimensions of the chamfer to a whole number of millimetres.  
 
C.6 Thickness of facing layer  
 
C.6.1 Apparatus  
Measuring equipment capable of measuring with an accuracy of 0.5 mm. 
 
C.6.2 Procedure  
Take a flag which has been broken.  
 
Measure the thickness of the facing layer on the broken face at the point where, by visual inspection, the  
value will be a minimum. Record the measurement to the nearest millimetre.  
 
The thickness of  the facing layer shall not be measured on the chamfer. Isolated particles of aggregate  
protruding into the facing layer shall be ignored.  
 
C.7 Examples of measuring equipment  
 
C.7.1 Metal rectangular box  
A metal rectangular box large enough to enclose a f lag. The horizontal base plate and two adjoining vertical 
sides fixed. The two other vertical sides can be moved horizontally parallel to the fixed sides. The distance 
between the pairs of parallel sides can be read from a scale to a whole number of millim etres. The 
construction of the apparatus has to be such that the accuracy of measurements obtained to a whole  
number of millimetres can be justified.  
 
C.7.2 Notched straight edge and gauge  
Dimensions in millimetres  KS  2017  
©KEBS 2005 — All rights reserved                7 X 
Figure C.1 — Example of a notched straight edge and gauge  
 
Table C.1 — Dimensions of a notched straightedge and gauge  
Dimension A  
mm Dimension X  
mm Dimension Y  
mm 
300 1.5 2.5 
400 2.0 3.5 
500 2.5 4.0 
800 4.0 6.5  
 
Figure C.2 — Example of a graduated square  
 
C.8 Test report  
 
The test report shall include all the measurements taken.  
 
See also clause 8.  
 
 
 
 
 
 
 
 
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  8 Annex D 
(normative)  
Determination of total water absorption  
 
D.1 Principle  
After conditioning the specimen to (20 ± 5) °C it is soaked to constant mass and then oven dried to  constant 
mass. The loss in mass is expressed as a percentage of the mass of the dry specimen.  
 
D.2 Specimen  
If a flag weighs more than 5 kg, it shall be cut to provide a specimen of the full thickness of the flag that  
weighs more than 2.5 kg but not more than 5.0 kg.  
 
D.3 Materials  
Potable water.  
 
D.4 Apparatus  
 
D.4.1 Ventilated drying oven with a capacity in litres over an area of ventilation channels in square 
millimetres  less than 0.2 in which the temperature may be controlled to (105 ± 5) °C. It shall have a volume 
at least 2½ times greater than the volume of specimens to be dried at any one time.  
 
D.4.2 Flat based vessel having a capacity at least 2½ times the volume of  the samples to be soaked and  
a depth at least 50 mm greater than the height of the specimens in the attitude that they will be soaked.  
 
 
D.4.3 Balance reading in grams and accurate to 0.1 % of the reading.  
 
D.4.4 Stiff brush.  
 
D.4.5 Cloth.  
 
D.5 Preparation of the test specimens  
Remove all dust, flashing, etc. with a brush and ensure that each specimen is at a temperature of (20 ± 5) 
°C. 
 
D.6 Procedure  
Immerse the specimens in potable water at a temperature of (20 ± 5) °C using the vessel until co nstant  
mass M 1 is reached. Separate the specimens from each other by at least 15 mm and ensure a minimum of 
20 mm water above them. The minimum period of immersion shall be three days and constant mass shall be 
deemed to have been reached when two weighing s performed at an interval of 24 h show a difference in 
mass of the specimen of less than 0.1 %. Before each weighing wipe the specimen with the cloth which has 
been moistened and squeezed to remove any excess of water. The drying is correct when the surfa ce of the 
concrete is dull.  
 
Place each specimen inside the oven in such a way that the distance between each specimen is at least  
15 mm. Dry the specimen at a temperature of (105 ± 5) °C until it reaches constant mass M 2. The minimum 
period of drying shal l be three days and constant mass shall be deemed to have been reached when two 
weighings performed at an interval of 24 hours show a difference in mass of the specimen of less than 0.1 
%. Allow the specimens to cool to room temperature before they are wei ghed.  
 
D.7 Calculation of test results  
Calculate the water absorption Wa of each specimen as a percentage of its mass from the equation:  
 
where  
M1 is the initial mass of the specimen (g);  
M2 is the final mass of the specimen (g).  
KS  2017  
©KEBS 2005 — All rights reserved                9  
Calculate the water absorption of the sample as the mean of the water absorption of the specimens.  
 
D.8 Test report  
The test report shall give the values of water absorption for each of the specimens.  
 
See also clause 8.  
 
Annex E 
(normative)  
Measurement of bending strength and breaking load  
 
E.1 Apparatus  
The transverse testing machine shall have a scale with an accuracy of ± 3 % over the range of the 
anticipated test loads and be capable of increasing the load at specified rates.  
 
It shall be constructed in such a way that it can induce 3 point bending into the specimen without torsion.  
The load inducing bar shall be equidistant between the supports.  
 
The length of the supports and the load inducing bar shall be at least equal to the width of the sample to be 
tested (see Fig ure E.1). 
 
The upper and lower bearers shall be parallel and rigid and round or rounded to a radius of (20 ± 1) mm.  
 
If packing pieces are used their width shall not exceed 25 mm. Their thickness shall be (4 ± 1) mm and at  
least  10 mm longer than the size of the anticipated fracture plane.  
 
 
Key 
1 Specimen flag  
2 Load bearing supports  
3 Load inducing bar  
 
Figure E.1 — Principle of testing  
 
The packing pieces shall be made of a material that meets the following hardness criterion : when submitted 
to a punching test by means of a rod of circular cross section, having a diameter of (16.0 ± 0.5) mm and 
applying a force at a rate of (48 ± 10) kN/min, the instantaneous penetration when the force of (20 ± 5) kN is 
achieved shall be equal  to (1.2 ± 0.4) mm.  
 
E.2 Preparation  
Use whole flags when their plan shape includes at least two parallel straight edges. In other cases use  
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  10 sawn specimens with the largest possible plan area which includes two parallel straight edges.  
 
If necessary remove  any burrs, high spots, etc. Immerse the flags under water at (20 ± 5) °C for (24 ± 3) h, 
remove, wipe dry and test immediately.  
 
A rough, textured or curved face shall be prepared by grinding or capping. Other methods of preparation  
may be used for routine testing providing there is a correlation between the results of the two methods, e.g. 
using unground rough, textured or curved flags instead of ground flags.  
 
NOTE Faces that are not rough, textured or curved may be prepared by grindin g or capping  
 
E.3 Procedure  
Place the flag in the testing machine. The distance between the load bearing supports and the edge of the 
flag shall be 25 mm, but if the span be less than three times the thickness, the distance between the load 
bearing support s and the edge of the flag shall be reduced to half the thickness of the flag.  
 
The span shall be within 0 .5 % of the specified span rounded to the nearest millimetre and recorded.  
 
Place the specimen with its upper face uppermost, symmetrically on the loa d bearing supports of the testing 
machine and with its shorter side parallel to the load bearing supports.  
 
Depending on the surface profile of the flag any one of the following shall be used at the discretion of the 
manufacturer:  
 
⎯ no packing;  
 
⎯ packing ; 
 
Apply the load without shock and increase the load uniformly so that the breaking load is reached within (45 
± 15) s.  
 
E.4 Calculation of test results  
Calculate the strength T in megapascals of the flag tested from the equation:  
 
where  
T is the strength, in megapascals;  
 
P is the breaking load, in newtons;  
 
L is the distance apart of the supports, in millimetres;  
 
b is the width of the flag at the failure plane, in millimetres;  
 
t is the height of the flag at the failure plane, in millimetres.  
 
NOTE The formula is not applicable for non -rectangular flags.  
 
Record the individual result T and the breaking load in kN.  
 
E.5 Test report  
 
The test report shall include the following information:  
 
a) the strength of the flag to the nearest 0,1 MPa;  
 
b) the breaking load of the flag to the nearest 0 .1 kN.  
 
See also clause 8.  
KS  2017  
©KEBS 2005 — All rights reserved                11  
Annex F 
(normative)  
 
Measurement of abrasion resistance  
 
F.1 Principle of wide wheel abrasion test  
The test is carried out by abrading the upper face of a paving flag with an abrasive material under standard 
conditions.  
 
F.2 Abrasive material  
The abrasive required for this test consists of a material comprising fused alumina (corundum) with a grit  
size of F80 in accordance with ISO 8486 -1. It shall not be used more than three times.  
 
F.3 Apparatus  
The wearing machine (see Figure G.1) is essentially made of a wide abrasion wheel, a storage hopper with 
one or two control valves to regulate the output of t he abrasive material, a flow guidance hopper, a  
clamping trolley and a counterweight.  
 
When two valves are used, one shall be used to regulate the rate of flow and can be permanently set while 
the other is used to turn the flow on and off.  
 
 
Key 
1 Clampin g trolley   8 Counterweight  
2 Fixing screw    9 Slot  
3 Specimen    10 Groove  
4 Control valve    11 Abrasive material flow  
5 Storage hopper   12 Abrasive collector  
6 Flow guidance hopper  13 Wedge  
7 Wide abrasion wheel  
Figure F.1 — Principle of wearing mach ine 
 
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  12 The wide abrasion wheel shall be made of a steel conforming to EN 10083 -2 and with a Brinell hardness of 
between 203HB and 245HB (as defined in  ISO 6506 -1,  ISO 6506 -2 and  ISO 6506 -3). Its diameter  
shall be (200 ± 1) mm and its width shall be (70 ± 1) mm. It shall be driven to rotate 75 revolutions in  
(60 ± 3) s.  
 
A mobile clamping trolley is mounted on bearings and forced to move forwards to the wheel by a  
counterweight.  
 
The storage hopper containing the abrasive material feeds a flow guidance hopper.  
 
The flow guidance hopper may be cylindrical and shall have a slotted outlet. The length of the slot shall be 
(45 ± 1) mm and width shall be (4 ± 1) mm. The body of the flow guidance hopper shall be at least 10 mm 
bigger than the slot in all direct ions. In the case of a rectangular hopper with at least one of the sides  
inclined down to the length of the slot, these dimensional limitations are not necessary (see Figure F.2, 
example 2).  
 
 
Dimensions in millimetres  
 
Key 
A Vertical side  
B Inclined side  
See Figure G.1  
Figure F.2 — Position of slot in the base of the flow guidance hopper  
 
The distance of the fall between the slot and the axle of the wide abrasion wheel shall be (100 ± 5) mm and 
the flow of the abrasive shall be 1 mm to 5 mm behind the lea ding edge of the wheel (see Figure F.3). 
 
Dimensions in millimetres  
KS  2017  
©KEBS 2005 — All rights reserved                13  
Key 
See Figure F.1 
Figure  F.3 — Position of slot relative to wide abrasion wheel  
 
The flow of the abrasive material from the flow guidance hopper shall be at least at a minimum rate of 2.5 
l/min onto the wide abrasion wheel. The flow of abrasive shall be constant and the minimum level of the  
abrasive in the flow guidance hopper shall be 25 mm (see Figure G.3).  
 
Useful tools for measuring the results are:  
 
⎯ a magnifying glass preferably equipped with a light, a steel ruler and a digital calliper.  
 
F.4 Calibration  
The apparatus shall be calibrated after grinding 400 grooves or every two months whichever is the lesser  
and every time there is a new operator, a new batch of abrasive, or a new abrasion wheel.  
 
The abrasive flow rate shall be verified by pouring the material from a height of approximately 100 mm into a 
pre-weighed rigid container with a smooth rim, of height ( 90 ± 10) mm and of known volume when filled to 
the top, this shall be approximately 1 l. As the container fills, the pourer shall be raised to maintain  
approximately the 100 mm fall. When the container is filled, the top shall be struck off level and weigh ed to 
determine the mass of abrasive for a known volume i.e. the density. Abrasive shall be run through the  
wearing machine for (60 ± 1) s and collected below the abrasion wheel in a pre -weighed container of at  
least 3 l capacity. The filled container shal l be weighed and from the density determined above, the rate of 
abrasive flow can be verified as more than or equal to 2.5 l/min.  
 
The apparatus shall be calibrated against a reference sample of 'Boulonnais Marble' using the procedure in 
G.6 and the counte rweight adjusted so that after 75 revolutions of the wheel in (60 ± 3) s the length of the 
groove produced is (20.0 ± 0.5) mm. The counterweight shall be increased or decreased to increase or 
decrease the groove length respectively. The clamping trolley/co unterweight assembly shall be checked for 
undue friction.  
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  14  
The groove shall be measured using the procedure in F.7 to the nearest 0.1 mm and the three results  
averaged to give the calibration value.  
 
An alternative material may be used for the reference sa mple if a good correlation is established with a  
reference sample of 'Boulonnais Marble'.  
 
The 'Boulonnais Marble' reference is:  
 
'Lunel demi -clair', thickness: > 50 mm, cut perpendicular to the bedding, ground with a diamond grit size 
100/120, roughness: Ra = (1.6 ± 0.4) μm when measured with a rugotest calibrated in accordance with  ISO 
4288.  
 
At every calibration of the apparatus the squareness of the sample supports shall be checked.  
 
The groove on the reference sample shall be rectangular with a differ ence between the measured length of 
the groove at either side not exceeding 0.5 mm. If necessary check that:  
 
⎯ the sample has been held square to the wheel;  
 
⎯ the clamping trolley and the slot from the flow guidance hopper are parallel to the wheel axle;  
 
⎯ the flow of abrasive is even across the slot;  
 
⎯ the friction in the trolley/counterweight assembly is not undue.  
 
F.5 Preparation of the specimen  
The test specimen shall be a whole product or a cut piece measuring at least 100 mm x 70 mm  
incorporating  the upper face of the unit.  
 
The test piece shall be clean and dry.  
 
The upper face, which shall be tested, shall be flat within a tolerance of ± 1 mm measured in accordance  
with C.4 in two perpendicular directions, but over 100 mm.  
 
If the upper face has  a rough texture or is outside this tolerance it shall be lightly ground to produce a smooth 
flat surface within tolerance.  
 
Immediately before testing, the surface to be tested shall be cleaned with a stiff brush and covered with a  
surface dye to facilita te measuring the groove (e.g. painting with a marker pen).  
 
F.6 Procedure  
Fill the storage hopper with dry abrasive material, moisture content not exceeding 1.0 %. Move the clamping 
trolley away from the wide abrasion wheel. Position the specimen on it so that the groove produced shall be 
at least 15 mm from any edge of the specimen and fix the specimen on a wedge to let  
the abrasive flow pass under it. Place the abrasive collector beneath the wide abrasion wheel.  
 
Bring the specimen into contact with the w ide abrasion wheel, open the control valve and simultaneously  
start the motor so that the wide abrasion wheel achieves 75 revolutions in (60 ± 3) s. Check the regularity of 
the flow of the abrasive material during the test visually. After 75 revolutions of  the wheel, stop the abrasive 
flow and the wheel. Whenever possible two tests shall be performed on each specimen.  
 
F.7 Measuring the groove  
Place the specimen under a big magnifying glass nominally at least 2 times magnification and preferably  
equipped  with a light to facilitate the measuring of the groove.  
 
With a pencil with a lead diameter of 0,5 mm and hardness 6H or 7H, draw the external longitudinal limits  
(I1 and I2) of the groove using a ruler (see Figure F.4). 
 KS  2017  
©KEBS 2005 — All rights reserved                15 Then draw a line (A - B) in the m iddle of the groove perpendicular to the centreline of the groove. Position a 
digital calliper square tips on the points A and B to the inside edge of the longitudinal limits (I1 and I2) of the 
groove and measure and record the dimension to the nearest ± 0 .1 mm.  
 
For calibration purposes, repeat the measurement (10 ± 1) mm from the ends of the groove (C D) to give  
three readings.  
 
Dimensions in millimetres  
 
 
Key 
Key: see Figure G.1  
Figure F.4 — Example of a tested specimen showing a groove  
 
Some surface dyes may be removed above the groove by action of the abrasive. This shall be ignored in  
producing line I1 which shall be drawn where the sample surface is abraded.  
 
F.8 Calculation of test results  
The result is the dimension corrected by a calibration factor and then rounded to the nearest 0.5 mm. The 
calibration factor is the arithmetic difference between 20 .0 and the recorded calibration value.  
 
If two grooves have been cut in a specimen the larger value shall be taken as the result.  
 
NOTE For example, if the calibration value is 19.6 mm and the dimension is 22.5 mm, the result is 22.5 + (20.0 -19.6) = 22.9 mm, 
rounded to 23.0 mm.  
 
F.9 Test report  
The test report shall include the lengths of the grooves.  
 
See also clause 8.  
 
 
Annex G 
(normative)  
 
Measuring of abrasion according to the Böhme test  
 
G.1 Principle  
Square sheets or cubes are placed on the Böhme disc abrader, on the test track of which standard abrasive 
is strewn, the disc being rotated and the specimens subjected to an abrasive load o f (294 ± 3) N for a given 
number of cycles (see G.5). 
 
The abrasive wear is determined as the loss in specimen volume.  
 
G.2 Abrasive material  
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  16 The standard abrasive used shall be fused alumina (artificial corundum)3) designed to produce an abrasive 
wear of 1.10 mm to 1.30 mm when testing standard granite specimens and of 4.20 mm to 5.10 mm when 
testing standard limestone specimens. Conformity with these requirements, the homogeneity of the material 
and the uniformity of bulk density and grading of the abrasi ve shall be checked.  
 
G.3 Apparatus  
 
G.3.1 Thickness measuring device . To establish the reduction in thickness, a dial gauge, the plunger of  
which shall have a spherical bearing and an annular contact face of 8 mm outside and 5 mm inside diameter, 
and a me asuring table, shall be used.  
 
G.3.2 Disc abrader . The Böhme disc abrader as shown in Figure H.1 consists essentially of a rotating  
disc with a defined test track to receive the abrasive, a specimen holder and a loading device.  
 
G.3.3 Rotating disc . The rotating disc shall have a diameter of approximately 750 mm and be flat and  
positioned horizontally. When loaded, its speed shall be (30 ± 1) revolutions per minute.  
 
The disc shall be provided with a revolution counter and a device that switches off the disc automatically  
after 22 revolutions.  
 
G.3.4 Test track . The test track shall be annular, with an inside radius of 120 mm and an outside radius of 
320 mm (i.e. be 200 mm wide), and be replaceable.  
 
The track shall be made of cast iron with a perliti c structure, a phosphorus content not exceeding 0.35 %  
and a carbon content of more than 3 %. The track shall have a Brinell hardness of 190 to 220 HB 2.5/187.5 
(as defined in  ISO 6506 -1,  ISO 6506 -2 and  ISO 6506 -3), determined as the mean from measureme nts 
taken at not less than ten points along the edge of the track.  
 
The track surface is subject to wear in service; the resulting reduction in thickness shall not exceed 0.3 mm 
and any grooves not deeper than 0,2 mm. If these values are exceeded, the trac k shall be replaced or 
refinished. When the track has been refinished three times, its hardness shall be determined anew.  
 
G.3.5 Specimen holder . The specimen holder shall consist of a U -frame approximately 40 mm high, with  
a clear distance of (5 ± 1) mm f rom the test track. The frame shall be positioned so that the centreline  
distance between specimen and disk is 220 mm and the angle bead of the specimen holder, which supports 
the specimen, is located at a distance of (4 ± 1) mm above the disk. The mountin g of the specimen holder 
shall ensure that, during testing, no vibration occurs.  
 
G.3.6 Loading device . The loading device shall consist of a lever of two arms of different length, a loading 
weight and a counterweight, the lever being pivoted with as littl e friction as possible and positioned almost 
horizontally during the test. The system shall be designed to ensure that the load is transferred vertically via 
the plunger to the centre of the specimen. The self -weight of the lever is balanced by the counter -weight and 
the scale to receive the loading weight. The force acting on the specimen results from the loading weight 
multiplied by the leverage ratio, the mass of the weight being selected to produce a test force of (294 ± 3) N 
(corresponding to about 0.0 6 N/mm2), which shall be verified by calculation.  
 
Dimensions in millimetres  KS  2017  
©KEBS 2005 — All rights reserved                17  
Key 
1 Counterweight  
2 Test track  
3 Loading weight  
4 Specimen holder  
5 Specimen  
6 Rotating disc  
Figure H.1 — Principle of Böhme disc abrader  
 
G.4 Preparation of specimens  
Use square slabs or cubes with an edge length of (71.0 ± 1.5) mm as specimens.  
 
The contact face and the opposite face of the specimen shall be parallel and flat. For determining the 
reduction in thickness as described in H.6, the opposite face shall, if appro priate, be ground parallel or 
otherwise machined so as to be parallel.  
 
Other than as provided below the specimens shall be dried to constant mass at a temperature of (105 ± 5) 
°C, pregrinding of the contact face by four cycles (see G.5) being usually requ ired. 
 
 
For the exceptional case of testing specimens in the wet or water -saturated condition (see H.5), the 
specimens shall be immersed for not less than seven days and wiped with a damp artificial sponge prior to 
each weighing so that all specimens appea r equally damp.  
 
Each specimen shall be taken from no less than three different samples or workpieces of the same type.  
Prior to testing, determine the density of the specimen, ρ R, by measurements, to the nearest 0.1 mm, and  
by weighing, to the nearest 0.1 g.  
 
In the case of two -layer specimens, determine the density for specimens taken separately from the wearing 
layer, such specimens also being ground prior to testing where necessary.  
 
G.5 Procedure  
Prior to the abrasion test and after every four cycles (see H.4), weigh the specimen to an accuracy of 0.1 g.  
 
Pour 20 g of standard abrasive on the test track. Clamp the specimen into the holder and, with the test  
contact face facing the track, load centrally with (294 ± 3) N.  
 
Start the disc taking care that the abrasive on the track remains evenly distributed over an area defined by 
the width of the specimen.  
 
Test the specimen for 16 cycles, each consisting of 22 revolutions.  
 
After each cycle, clean both disc and contact face, and turn the specimen progressively through 90° and  
pour new abrasive on the track as described in H.2.  
 
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  18 When testing damp or water -saturated specimens, prior to each cycle, the track shall be wiped with a lightly 
damp artificial sponge and moistened befor e being strewn with abrasive. From the start of the test, water 
shall be caused to drip, at a rate of approximately 13 ml of water (corresponding to 180 drops to 200 drops) 
per minute onto the track from a container with an adjustable pivoting nozzle. The drops shall fall through a 
distance of approximately 100 mm on the middle of the track at a point 30 mm in front of the specimen. 
When testing in accordance with this method, care shall be taken to ensure that the abrasive is continuously 
returned to the e ffective area of the track (see G.3). 
 
G.6 Calculation of test results  
Calculate the abrasive wear after 16 cycles as the mean loss in specimen volume ΔV, from the equation:  
 
where  
ΔV is the loss in volume after 16 cycles in cubic millimetres;  
Δm is the loss in mass after 16 cycles in grams;  
ρR is the density of the specimen or, in the case of multi -layer specimens, the density of the wearing layer in 
grams per cubic millimetre.  
 
G.7 Test report  
Report the abrasive wear to the nearest whole number  of 1 000 mm3 per 5 000 mm2. 
See also clause 8.  
 
Annex H 
(normative)  
 
Method for the determination of unpolished slip resistance value (USRV)  
 
H.1 Principle  
The measurement of USRV on the specimen is made using the pendulum friction test equipment to evaluate 
the frictional properties of the specimen on the upper face.  
 
The pendulum friction test equipment incorporates a spring loaded slider made of a standard rubber 
attached to the end of the pendulum. On swinging the pendulum the frictional force bet ween the slider  
and test surface is measured by the reduction in length of the swing using a calibrated scale.  
 
H.2 Apparatus  
 
H.2.1 Pendulum friction tester  
 
H.2.1.1 The pendulum friction test equipment shall be manufactured as shown in Figure I.1. All bearings and 
working parts shall be enclosed as far as possible, and all materials used shall be treated to prevent 
corrosion under wet conditions.  
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©KEBS 2005 — All rights reserved                19  
Key 
1 C scale (126  mm sliding length)  
2 F scale (76 mm sliding length)  
3 Pointer  
4 Pendulum  
5 Rubber slider  
6 Levelling screw  
7 Test specimen holder  
8 Spirit level  
9 Vertical adjustment screw  
 
Figure H.1 — Pendulum friction test equipment  
H.2.1.2 The pendulum test equipment shall have the following features:  
1) a spring loaded rubber coated slider as specified in H.2.1.4 to H.2.1.10. It shall be mounted on the end of 
a pendulum arm so that the sliding edge is (510 ± 1) mm from the axis of suspension;  
 
2) means of setting the support column of the equipment vertical;  
 
3) a base of sufficient mass to ensure the equipment remains stable during the test;  
 
4) means of raising and lowering the axis of suspension of the pendulum arm so that the slider can:  
 
⎯ swing  clear of the surface of the specimen; and  
 
⎯ be set to traverse a surface over a fixed length of (126 ± 1) mm. A gauge with this distance marked is 
required as shown in Figure H.2. 
 
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  20  
Key 
1 Gauge  
2 Slider  
3 Reference edge  
4 Sliding length measured  
5 Actua l sliding length  
Figure  H.2 — Sliding length gauge  
 
5) Means of holding and releasing the pendulum arm so that it falls freely from a horizontal position;  
 
6) A pointer of nominal length 300 mm, balanced about the axis of suspension, indicating the position of the 
pendulum arm throughout its forward swing and moving over the circular scale. The mass of the pointer shall 
be not more than 85 g;  
 
7) The friction in the pointer mechanism shall be adjustable so that, with the pendulum arm swinging freely 
from a horizontal position, the outward tip of the pointer may be brought to rest on the forward swing of the 
arm at a point (10 ± 1) mm below the horizontal. This is the 0 reading;  
 
8) A circular C scale, calibrated for a sliding length of 126 mm on a fla t surface, marked from 0 to 150 at 
intervals of five units.  
 
H.2.1.3 The mass of the pendulum arm, including the slider, shall be (1 .50 ± 0 .03) kg. The centre of gravity 
shall be on the axis of the arm at a distance of (410 ± 5) mm from the axis of suspens ion. 
 
H.2.1.4 The wide slider shall consist of a rubber pad (76 .2 ± 0 .5) mm wide; (25 .4 ± 1 .0) mm long (in the 
direction of swing) and (6 .4 ± 0 .5) mm thick, the combined mass of slider and base shall be (32 ± 5) g.  
 
H.2.1.5 The slider shall be held on a ri gid base with a centre pivoting axis which shall be mounted on the end 
of the pendulum arm in such a way that, when the arm is at the lowest point of its swing with the trailing edge 
of the slider in contact with the test surface, the plane of the slider i s angled at (26 ± 3)° to the horizontal. In 
this configuration the slider can turn about its axis without obstruction to follow unevenness of the surface of 
the test specimen as the pendulum swings.  
 
KS  2017  
©KEBS 2005 — All rights reserved                21 H.2.1.6 The slider shall be spring -loaded against the te st surface. When calibrated, the static force on the 
slider as set by the equipment calibration procedure shall be (22 .2 ± 0 .5) N in its median position. The 
change in the static force on the slider shall be not greater than 0 .2 N per millimeter deflection  of the slider.  
 
H.2.1.7 The initial resilience and hardness of the slider shall conform to Table H.1, and shall have a 
certificate of conformity including the name of the manufacturer and date of manufacture. A slider shall be 
discarded when the IRHD value measured in accordance with ISO 7619 fails to conform to the requirements 
of the table or not later than three years after manufacture.  
 
Table H.1 — Properties of the slider rubber  
 Temperature °C  
Property  0 10 20 30 40 
Resilience (%)  43 to 49  58 to 65  66 to 73  71 to 77  74 to 79  
H a r d n e s s  
( I R H D )2)  
53 to 65  
1 Rebound test in accordance with ISO 4662. 
2) International Rubber Hardness Degrees in accordance with ISO 48. 
 
H.2.1.8 The edges of the slider shall be square and clean -cut, and the rubber free from contamination by, for 
example, abrasive or oil. The slider shall be stored in the dark at a temperature in the range 5 °C to 20 °C.  
 
H.2.1.9 Before using a new slider it shall be conditioned to produce a minimum width of striking edge of 1 
mm as shown in Figure I.3.  
 
This shall be achieved by setting up the tester and carrying out five swings on a dry surface with a friction 
value above 40 on the C scale followed by a further 20 swings on the same surface after wetting.  
 
 
KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  22  
 
Key 
1 Rubber slider  
2 Aluminium backing  
3 Striking edge  
4 Worn width  
 
Figure  H.3 — Slider assembly illustrating the maximum wear of striking edge  
 
H.2.1.10 The slider shall be discarded when the width of the striking edge as shown in Figure H.3 exceeds 3 
mm or becomes excessively scored or burred. The slider can be reversed to expose a new edge, which will 
need to be conditioned.  
 
H.2.2 A container with potable water at (20 ± 2) °C for wetting the surfaces of the test specimen and slider.  
 
H.3 Calibration  
The apparatus shall be recalibrated at least annually.  
 
H.4 Sampling  
Obtain a representative sample of five flags of the same surface family.  
 
Each flag in the sample shall permit a test area of 136 mm x 86 mm which is representative of the whole 
flag. This area shall b e tested using the 76 mm wide slider over a nominal swept length of 126 mm, readings 
being taken on the C scale.  
 
In the case of large flags, representative samples shall be cut from them for test.  
 
H.5 Procedure  
Keep the friction test equipment, and slide r, in a room at a temperature of (20 ± 2) °C for at least 30 min 
before the test begins.  
 
Immediately prior to testing with the friction tester, immerse the sample in water at (20 ± 2) °C for at least 30 
min. 
 
Place the friction tester upon a firm level su rface and adjust the levelling screws so that the pendulum 
support column is vertical. Then raise the axis of suspension of the pendulum so that the arm swings freely, 
and adjust the friction in the pointer mechanism so that when the pendulum arm and point er are released 
from the right -hand horizontal position the pointer comes to rest at the zero position on the test scale.  
 
Before using a new slider condition it using the method described in H.2.1.9.  
 
Discard any slider that exceeds the requirements given  in H.2.1.10.  
 
KS  2017  
©KEBS 2005 — All rights reserved                23 Rigidly locate the test specimen with its longer dimension lying in the track of the pendulum, and centrally 
with respect to the rubber slider and to the axis of the suspension of the pendulum. Ensure that the track of 
the slider is parallel to the long ax is of the specimen across the sliding distance. Adjust the height of the 
pendulum arm so that in traversing the specimen the rubber slider is in contact with it over the whole width of 
the slider and over the specified swept length. Wet the surfaces of the  specimen and the rubber slider with a 
copious supply of water, being careful not to disturb the slider from its set position. Release the pendulum 
and pointer from the horizontal position, catch the pendulum arm on its return swing. Record the position of  
the pointer on the scale (the pendulum test value). Perform this operation five times, rewetting the specimen 
each time, and record the mean of the last three readings. Relocate the specimen after rotating through 180 
° and repeat the procedure.  
 
H.6 Calculation of test results  
When the wide slider is used over a swept length of 126 mm, calculate the pendulum value of each 
specimen as the mean of the two recorded mean values measured in opposite directions to the nearest 1 
unit on the C scale.  
 
The USR V is the mean pendulum value obtained on the 5 specimens.  
 
H.7 Test report  
 
The test report shall include the following information:  
1) the mean pendulum test value of each specimen;  
2) the mean USRV of the sample.  
 
See also clause 8.  
 
Annex I 
(normative)  
 
Verification of visual aspects  
 
I.1 Preparation  
Lay out close together the samples at floor level in a shape approximating to a square after examining each 
unit for delamination.  
 
I.2 Procedure  
In natural daylight conditions an observer shall stand in turn at a distance of 2 m from each edge of the 
square and record any flag showing cracks or flaking.  
 
Compare the texture and the colour with the manufacturer’s sample.  
 
Annex J 
(informative)  
 
Example of the application of the method for the evaluation of  conformity of either 
bending strength or breaking load by variables (6.3.8.3.B)  
 
J.1 General  
For factory production control by the manufacturer conformity may be determined either by attributes or by 
variables (see 6.3.8.3 B).  
 
Based on the measuring of either bending strength or breaking load the flow -chart (see Figure J.1) herewith 
shows the possible “routes”: either by attributes or by variables; but it is always started by attributes because 
the variables route needs enough r esults to calculate the standard deviation.  
 
The probability of acceptance is to be equivalent to that resulting from testing by “Attributes” (6.3.8.3 A).  
 
J.2 Basic formula  
The basic formula to check the conformity of a given production is for three stren gth classes:  
 KS: 2017  
 
                  ©KEBS 2017 — All rights reserved  24  
 
J.3 Acceptance factors  
Depending on the number of samples the acceptance factors are:  
n = 4  q4 = 0.9  
n = 2  q2 = 0.6  
n = 16  q16 = 1.3  
 
J.4 Standard deviations s  
Different methods may be used for the determination of the standard deviation s depending on the accuracy 
needed.  
 
 
The minimum number of results to determine the standard deviation depends on the process stability:  
commonly  30 results are used, but if the stability is proved 15 may be enough. These results (30 or 15) 
should be gathered from tests of a representative production period, e.g. 4 production days 8 results or 4 
results per day.  
 
At regular intervals the standard d eviation should be checked.  
 
J.5 Application of switching rules  
 
When the production is under control, the number of samples tested decreases.  
 
That is logical, because the probability to produce defectives decreases. The switching rules are given in 
A.5. 
 
J.6 Results  
If the result of using the formula in J.2 is positive and no individual result T is below 2.8 MPa, 3.2 MPa or 4.0 
MPa respectively according to the strength class, the corresponding production complies with the 
requirements of this standard.  
 
If the results do not meet the requirements, 6.3.7 applies.  
 
KS  2017  
©KEBS 2005 — All rights reserved                25  
 
Figure J.1 — EN 1339 bending strength example for class 1 in Table 5