ICS 91.100.25  
 
Reference number  
DRS 512 : 2022  
© RSB 2022  
  
 RWANDA 
STANDARD  DRS 
512  
 
First e dition  
2022 -mm-dd 
 
Clay roofing tiles and ridges — 
Specification  
   
DRS 512: 2022    
©RSB 2022 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2022  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS 512: 2022  
iii                ©RSB 2022  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 General requirements  ................................ ................................ ................................ ..................  3 
4.1.1  Workmanship  ................................ ................................ ................................ ................................  3 
4.1.2  Appearance  ................................ ................................ ................................ ................................ ... 3 
4.1.3  Design  ................................ ................................ ................................ ................................ ............  3 
4.1.4  Manufacturing  ................................ ................................ ................................ ...............................  3 
4.2 Specific requirements  ................................ ................................ ................................ ..................  3 
4.2.1  Performance requirements  ................................ ................................ ................................ ..........  3 
4.2.2  Lugs (for Mangalore and Marseille tiles)  ................................ ................................ ....................  4 
4.2.3  Corrugations and cross ribs  ................................ ................................ ................................ ....... 4 
4.2.4  Tolerance on dimensions  ................................ ................................ ................................ ............  5 
5 Marking  ................................ ................................ ................................ ................................ ..........  5 
6 Sampling  ................................ ................................ ................................ ................................ ....... 5 
Annex  A (informative)  Patterns of Ma rseille, Mangalore, Portuguese and Roman  ...........................  6 
Annex  B (normative)  Permeability test  ................................ ................................ ................................ .. 9 
B.1 Test specimen  ................................ ................................ ................................ ...............................  9 
B.2 Apparatus  ................................ ................................ ................................ ................................ ...... 9 
B.3 Procedure  ................................ ................................ ................................ ................................ ...... 9 
Annex  C (normative)  Determination of breaking load  (for Mangalore and Marseille tiles)  ............  10 
C.1 Test specimen  ................................ ................................ ................................ .............................  10 
C.2 Apparatus  ................................ ................................ ................................ ................................ .... 10 
C.3 Procedure  ................................ ................................ ................................ ................................ .... 10 
C.4 Results  ................................ ................................ ................................ ................................ .........  10 
Annex  D (normative)  Determination of breaking load (for Roman and Portuguese tiles)  ..............  11 
D.1 Test specimen  ................................ ................................ ................................ .............................  11 
D.2 Apparatus  ................................ ................................ ................................ ................................ .... 11 
D.3 Procedure  ................................ ................................ ................................ ................................ .... 11 
D.4 Results  ................................ ................................ ................................ ................................ .........  11 
 DRS 512: 2022    
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 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratifie d by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS 546  was prepared by Technical Committee RSB/TC 9, Civil engineering and building materials . 
In the preparation of this standard, reference was made to the following standard:  
US 816: 2018 , Clay roofing tiles and ridges — Specification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on  Civil engineering and building 
materials (RSB/TC 9) in the preparation of this standard.  
A+Construction Group Ltd  
Africeramics Ltd  
Consultants Engineers Group (CEG) Ltd  
D&D Resources Ltd  
Dutureheza Ltd  
Enabel Rwanda  
Greenpack Africa Ltd  
Integrated Polytec hnic Regional Centre (IPRC) - Musanze  
Mass Design Group  
NP Construction Construction Company (NPCC) Ltd  
Road Transport Development Agency (RTDA)  
Rwanda Housing Authority (RHA)  DRS 512: 2022  
v                ©RSB 2022  - All rights reserved  
 Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA)  
Rwand a Quarries Association (RQA)  
SKAT Consult  
St Joseph Engineering Company (SJEC) Ltd  
Standards for Sustainability (SfS)  
Stonecraft Industries Ltd  
University of Rwanda - College of Science and Technology (UR - CST)  
Rwanda  Standards Board  (RSB) – Secretariat  
 DRS 512 : 2022  
1                ©RSB 2022  - All rights reserved  
 Clay roofing tiles and ridges — Specification  
1 Scope  
This Draft Rwanda S tandard specifies requirements , sampling and test methods  for roofing tiles and ridges 
intended for use as roof covering where durability and appearance are required to provide a weathe r-resistant 
surface of specified design.  
2 Normative reference s 
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.  
RS ISO 10545 -1, Ceramic tiles — Part 1: Sampling and basis for acceptance  
RS ISO 10545 -2, Ceramic tiles — Part 2: Determination of dimensions and surface quality  
DRS 546 , Clay products for buildings — Vocabularies  
3 Terms and definitions   
For the purpose of this standard, terms and definitions given in DRS 546  and the following apply . 
3.1 
clay 
earthy or stony mineral aggregate consisting essentially of hydrous silicate of alumina; plastic when  sufficiently 
pulverized and wetted; rigid when dry; and vitreous when fired to a sufficiently high temperature  
3.2 
clay roofing tile  
solid unit of clay formed into any of a range of generally rectangular planar shapes while plastic and fired in kiln 
and a re used for roofing  
3.3 
ridge tile  
solid unit of clay formed into a triangular shape covering the apex of two slopes on a pitched roof   
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 3.4 
defective  
tile or ridge that fails to comply with the relevant requirements of the specification  
3.5 
lot 
not more than 20 000 roofing tiles of the same type and nominal dimensions, from one manufacturer, submitted 
for inspection and testing  
3.6 
drying shrinkage  
percentage reduction in length or volume of tiles on drying, due to the removal of the film of water which 
surrounds the individual grains in the plastic form.  
3.8  
face of tile  
upper surface of the tile when fixed on the roof  
3.9  
back of tile  
lower surface of the tile when fixed on the roof  
3.10  
breaking load  
load at which the roofing tile or ridge break s during testing  
3.11  
water absorption  
percentage amount of water absorbed by the roofing tile or ridge  DRS 512 : 2022  
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 4 Requirements   
4.1  General requirements  
4.1.1  Workmanship  
The roofing tiles and ridges shall be made from clay of even texture and shall be well-burnt throu ghout. They 
shall be free from irregularities  including  twists, bends, cracks and laminations.  
The roofing tiles  and ridges  shall be free from impurities like particles of stone, lime or foreign materials visible 
to the naked eye either on the surface or on the fractured face of the tile obtained by breaking the tile  or ridge . 
When struck, the tile  and ridge  shall give a characteristic ringing sound and when broken the fracture shall be 
clear and sharp at the edges.  
4.1.2  Appearance  
Tiles and ridges shall be well burnt and free from cracks and unslaked lime particles, and from excrescences 
and depressions not for ming part of the pattern of the tile or ridge. Surface grazing shall not be regarded as a 
defect.  
4.1.3  Design  
The patterns of Marseille, Mangalore, Portuguese and Roman  tiles are shown  in Annex A  in figures A.1, A.2, 
A.3, and A.4 and ridges are shown in A.5.  
The gap at the corners of the tiles  and ridges , when placed on plain surface in the normal position, shall be not 
more than 8.0 mm.  The design shall provide a good interlocking arrangement securing the roof against leakage 
or rain water. Clay roofing  tiles and ridges shall be free from faulty shape or any other defects liable to affect 
their strength or suitability for use.  
4.1.4  Manufacturing  
Tiles shall be manufactured in a system that ensures consistency in quality. The system sh all put in place 
measures to ensure the quality of raw materials, production and post -production management. The system shall 
be documented.  
4.2  Specific requirements  
4.2.1  Performance requirements  
Clay roofing tiles shall comply with the specific requirements gi ven in Table 1 when tested in accordance with 
test methods specified therein.  
  
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 Table 1 — Performance  requirements for tiles  and ridges  
Parameter  Requirement  Test method  
Tiles  Ridges  
Mangarole/Marseille  Roman/Portuguese  
Water absorption, %, 
max.  14 14 14 RS ISO 10545 -3 
Breaking load, 
N/minute, min.  
Average  
Individual  4.5 
4.0 13.0 
10.0 4.5 
4.0 RS ISO 10545 -4 
Permeability  
No water is found dripping at the bottom of the tile or ridge after 
the test  
 Annex B  
 
 
4.2.2   Lugs  (for Mangalore and Marseille tiles)  
4.2.2.1  Batten lug  
The tile shall have at least two batten lugs with a base thickness (thickness at the bottom) not less than 15 mm 
and a thickness at the top not less than 10 mm. The projection from the surface of the tile sh all be between 7 
mm and 12 mm (see Figure  A.1 and Figure A.2).  
4.2.2.2  Eaves lugs  
The tile shall have at least two eaves lugs with a base thickness not less than 15 mm and a thickness at the top 
not less than 10 mm. The projection from the surface of the lug shal l be not less than 10 mm and shall be 
shaped to fit into the corrugations (see Figure A.1 and Figure A.2).  
4.2.3  Corrugations and cross ribs  
The cross -section of the roofing tile shall be such as to give the tile structural rigidity. This may be achieved by 
providing longitudinal corrugations with intermediate cross ribs or stiffeners (see Figure A.1 and Figure A.2).  DRS 512 : 2022  
5                ©RSB 2022  - All rights reserved  
 4.2.4  Toleran ce on dimension s 
When measured in accordance with RS ISO 10545 -2, the dimensions for clay roofing  tiles shall be as declared 
by the manufacturer or as agreed between to the purchaser and the manufacturer, subject to the tolerance of ± 
5 mm.  
5 Marking  
5.1 The following informati on shall be legibly engraved  on the back of each tile and ridge:  
a) name, trade name or trade mark of the manufacturer; and  
b) batch number.  
5.1.1  Where the batch number on an individual tile or ridge is not possible, it shall be provided on a 
consignment slip in a package or on the package.  
5.2 The tiles and ridges shall be packaged with a brochure bearing the following information;  
a) weight per square metre; and  
b) dimensions (length, width and thickness).  
6 Sampling  
Sampling shall be done in accordance with RS ISO 10545 -1.  
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 Annex  A 
(informative)  
 
Patterns of Marseille, Mangalore, Portuguese and Roman  
The patterns of Marseille, Mangalore, Portug uese and Roman are shown in Annex A in figures A.1, A.2, A.3, 
and A.4.  
 
 
Figure A.1 — Typical details of a Mangalore  tile (dimensions in millimetres)  
DRS 512 : 2022  
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Figure A. 2 — Typical details of Marseille tile  (dimensions in millimetr es)  
 
Figure A.3  — Typical  details of  Portuguese tile  (dimensions  in millimetr es)   
 
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Figure A.4  — Typical details of Roman tile (Dimensions in millimetres)  
 
Figure A.5 — Typical details of ridge (dimensions in millimetr es)  
DRS 512 : 2022  
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 Annex  B 
(normative)  
 
Permeability test  
B.1 Test specimen  
Ten tiles shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for this test.  
Ten ridges shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for this test . 
B.2 Apparatus  
The test shall be conducted in a rectangular trough (see Figure 6) which is open at the bottom, the dimensions 
at the bottom being equal to the size of the tile.  
B.3 Procedure  
B.3.1  The test shall be conducted at a temperature of  27 °C ± 2 °C and relative humidity of 65 % ± 5 %.  
B.3.2  The tile (or ridge) shall be fitted at the bottom of the trough and the space between the tile and the sides 
of the trough plugged water -tight with suitable material like wax, bitumen, etc.  
Water s hall be poured into the mould so that it stands over the lowest tile surface to a height of 50 mm.  
B.3.3  The water in the trough shall be allowed to stand for a period of six hours. The bottom of the tile shall 
then be carefully examined to see whether th e water has seeped through the tile . 
  
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 Annex  C 
(normative)  
 
Determination of breaking load (for Mangalore and Marseille tiles)  
C.1 Test specimen  
Ten tiles shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for th is test.  
C.2 Apparatus  
A suitable form of apparatus is shown in Figure 7, consisting of two parallel self -aligning steel bearers, with the 
bearing surface rounded to 38 mm diameter, so placed that the distance between the centres could be altered. 
The load i s applied through a third steel bearer of similar shape midway between and parallel to the supports. 
The length of all the bearers shall exceed the maximum width of the tile under test.  
C.3 Procedure  
Test ten tiles in wet condition after soaking them in wate r at 20 ºC ± 2 ºC for 24 h. Support the tile centrally on 
the bearer set with a span of 25 cm and resting on the bottom surface. Apply the load with the direction of the 
load perpendicular to the span, at a uniform rate of 440 N/min to 540 N/min.  
C.4 Results  
Report the average breaking load from the ten tests in N/mm width.  
 DRS 512 : 2022  
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 Annex  D 
(normative)  
 
Determination of breaking load (for Roman and Portuguese tiles)  
D.1 Test specimen  
Ten tiles randomly selected to form the sample size according to the lot size as shown in Table 3 shall be used 
for this test.  
Ten ridges shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for this te st. 
D.2 Apparatus  
This test may be conducted with any standard compression testing machine with provision for adjusting the rate 
of loading. A typical arrangement is shown in Figure 8.  
D.3 Procedure  
Ten tiles or ridges in wet condition after soaking in water for 24 h shall be tested. The two longitudinal edges of 
the Roman or Portugal tile shall be kept, in normal position, over two strips of 25 mm thick rubber sheet placed 
on the table of the testing  machine.  
The load shall be applied to the tile or ridges by means of a wooden block of size 75 mm x 100 mm x 300 mm 
lined with rubber at the bottom, located symmetrically. The load shall be applied to the block at a uniform rate 
of 450 N/min – 600 N/min.   
D.4 Results  
The individual breaking strength shall be obtained by dividing the breaking load by the width of the tile and the 
average of the value shall be calculated. The result shall be expressed in N/mm width.   
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DRS 512 : 2022  
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 Bibliography  
[1] KS 431 -1: 2006, Clay roof ing tiles — Specification  
 DRS 512 : 2022  
 
Price based on  14 pages  
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