KENYA STANDARD DKS2802-4:201 8
ICS
Masonry units —Methods of test
Part 4:
Determination of water absorption of clay masonry
damp proof course units by boiling in water
Public Review Draft March2018
© KEBS 2018 First Edition ,2018DKS2802-4:201 8
ii ©KEBS 201 8—All rights reservedTECHNICAL COMMITTEE REPRES ENTATION
The following organizations were represented on the Technical Committee:
National Housing Corporation
Kenya Clay Products Ltd
Coast Clay Works Ltd
Consumer Information Network
University of Nairobi
Kenya Industrial Research & Development Institute
Architectural Association of Kenya
M&O Consulting Engineers
Kenya Association of Manufacturers,
Miritini Building Products Ltd .
Kenya National Federation of Jua Kali Association
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, 201 7
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copy right subsists
in all Kenya Standards and except as provided under Section 25 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 f rom the
Managing Director.KENYA STANDARD DKS2802-4:201 8
ICS
© KEBS 201 8—All rights reserved iiiMasonry units —Methods of test
Part 4:
Determination of water absorption of clay masonry damp
proof course units by boiling in water
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) 21814DKS2802-4:201 8
iv ©KEBS 201 8—All rights reservedForeword
This Kenya Standard was prepared by the Clay and Clay Products Technical Committee under the guidance
of the Standards Projects Committee and in accordance with the procedures of the Kenya Bureau of
Standards.
During the development of this standard, reference was made to the following documents:
EN 772 -7, Methods of test for masonry units —Part 7: Determination of water absorption of clay
masonry damp proof course units by boiling in water
Acknowledgement is hereby made for the assistance received from these sources .KENYA STANDARD DKS2802-4:201 8
© KEBS 201 8—All rights reserved 1Masonry units —Methods of test
Part 4:
Determination of water absorption of clay masonry damp proof course
units by boiling in water
1 Scope
This Kenya Standard specifies a method for determining the water absorption of damp proof course clay
masonry units by boiling the specimens in water for a fixed period.
2 Normative references
The following referenced documents are indispensable 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.
DKS 2801 -1 Masonry Units —Specification —Part 1: Clay Masonry Units.
3 Symbols
Ws is the water absorption of the specimen (%).
Md is the mass of the dry specimen (g).
Ms isthe mass of the saturated specimen (g).
4 Principle
The specimens, after drying to constant mass, are weighed and, subsequently immersed in water which is
boiled for 5 h, wiped and weighed. The ratio of increase in mass of the saturated specimens to the drymass
is calculated.
5 Apparatus
5.1 Ventilated oven , capable of maintaining a temperature of 105 ºC ± 5 ºC,
5.2 Weighing instrument ,capable of weighing the masonry units to an accuracy of 1 g.
5.3 Water tank , with adequate capacity to submerge the whole specimen and provided with a grid so
that free circulation of water around all surfaces of the specimen can be achieved.
6 Preparation of specimens
6.1 Sampling2 ©KEBS 201 8—All rights reservedThe method of sampling shall be in accordance with DKS 2801:1 .  The minimum number of specimens shall
be six, but a larger minimum number may be specified in the product specification, in which case that larger
number shall be used.
6.2 Drying of specimens
The test specimens shall be dried to constant mass in a ventilated oven (5.1) at a temperature of 105 °C ±
5 °C. Constant mass is reached if, during the drying process, in two consecutive weighings 24 h apart, the
loss in mass between the two determinations is not more than 0.2 % of the total mass.
7 Test procedure
Weigh the specimen after drying ( md). Place the specimen into a tank of water (5.3) immediately after weighing
ensuring that water can circulate freely on all sides. Heat the water to boiling point in approximately 1 h, boil
continuously for 5 h, and then allow to cool to room temperature by natural loss of heat for not less than 16 h.
Remove the specimen, wipe off the surface water with a damp cloth, and weigh within 2 min after its removal
from the water ( ms) When wiping perforated units, water that might otherwi se be left in the perforations shall
be removed by shaking.
8 Calculation and expression of results
Report the water absorption ( Ws) of each specimen as the ratio of the increase in mass of the saturated
specimen to the mass of the dry specimen. Calculat e this to the nearest 0.1 % using the following equation:
%100MdMdMsWs ………………………………………….eqn (1)
9 Evaluation of results
Calculate the mean value of the water absorption of the specimens to the nearest 0.1 %.
10 Test report
The test report shall contain the following information:
a)thenumber, title and date of issue of this Kenyan Standard;
b)thename of the organization that earned  out the sampling and the method used;
c)thedate of testing;
d)the type, origin and designation  of the masonry unit by reference  to DKS2801:1
e)the number of specimens  in sample;
f)the net volume of each specimen  and the mean value to the nearest  104mm3;
g)the percentage  of voids of each specimen  and the mean  value, ifrequired, to the nearest  1%; and
h)remarks, if any.