Concrete roofing tiles Specification...1) SANS 542:2020, Concrete roofing tiles 2) ASTM C1492 − 03 (2016) Standard Specification for Concrete Roof Tile The assistance derived from

ICS 91.100.30

Reference number

DRS 260: 2014

© RSB 2021

RWANDA STANDARD

DRS

260

Second edition

2014-07-08

Reaffirmed 2021-mm-dd

Concrete roofing tiles — Specification

DRS 260: 2014

©RSB 2021 - 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 2021

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DRS 260: 2014

iii ©RSB 2021 - All rights reserved

Contents Page

1 Scope ............................................................................................................................................. 1

2 Normative references ................................................................................................................... 1

3 Terms and definitions .................................................................................................................. 1

4 Symbols ......................................................................................................................................... 3

5 Requirements ................................................................................................................................ 4

6 Compliance and sampling ........................................................................................................... 8

7 Methods of test ............................................................................................................................. 9

8 Marking, labelling and packaging ............................................................................................... 9

Annex A (normative) Concrete roofing tiles-Method of test .............................................................. 10

DRS 260: 2014

©RSB 2021 - All rights reserved iv

Foreword

Rwanda Standards 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 Standards adopted by Technical committees are ratified by members of RSB Board of Directors for publication and gazettment as Rwanda Standards.

DRS 260 was prepared by Technical Committee RSB/TC 009, Building materials and civil engineering.

In the preparation of this standard, reference was made to the following standard (s):

1) SANS 542:2020, Concrete roofing tiles

2) ASTM C1492 − 03 (2016) Standard Specification for Concrete Roof Tile

The assistance derived from the above source is hereby acknowledged with thanks.

Committee membership

The following organizations were represented on the Technical Committee on Building materials and civil engineering (RSB/TC 009) in the preparation of this standard.

Bridge to Prosperity

City of Kigali

MASS Design

NPD Ltd

Rwanda Housing Authority (RHA)

Rwanda Public Procurement Authority (RPPA)

Standards for Sustainability (SFS)

University of Rwanda - College of Science and Technology (UR - CST)

Rwanda Standards Board (RSB) – Secretariat

DRS 260: 2014

1 ©RSB 2021 - All rights reserved

Concrete roofing tiles — Specification

1 Scope

This Draft Rwanda Standard covers concrete roofing tiles of plain and interlocking types made from lightweight or normal weight aggregates or both.

This standard covers concrete roofing tiles intended for the use as roof covering where durability and appearance are required to provide a weather-resistant surface of specified design.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 EAS 18-1, Cement — Part 1: Composition, specification and conformity criteria for common cements.

RS 373, Aggregates for concrete — Specification

3 Terms and definitions

For the purposes of this standard, the following terms and definitions apply.

3.1

acceptable

acceptable to the authority administering this standard or to the parties concluding the purchase contract, as relevant

3.2

defective

tile that fails in one or more respects to comply with the appropriate requirements of the standard

3.3

lot

not less than 500 and not more than 5 000 tiles of the same type, pattern, and dimensions, from one manufacturer, submitted at any one time for inspection and testing

©RSB 2021 - All rights reserved 2

3.4

additive

product which is added in small quantities in proportion to the mass of the cement before or during mixing or during an additional mixing operation, causing required modifications to the properties

3.5

aggregate

concrete component consisting of uncrushed or crushed natural substances (or both) and artificial mineral substances with particle sizes and shapes suitable for the production of concrete

3.6

average transverse strength

average value of the transverse strengths of the individual tiles

3.7

cement

hydraulic binder, i.e. finely ground inorganic materials which, when mixed with water, form a paste which sets, by means of hydration and which, after hardening, retains its strength and stability

3.8

interlocking tile (IL)

profiled or flat tile with a system of ribs or grooves enabling the lateral joining of adjacent tiles in the same horizontal row, with the overlapping lock covering the underlapping lock

3.9

non-interlocking tile (NL)

generally flat, cross cambered or longitudinally (or both) cambered tile, which is usually rectangular in shape, with or without a featured front edge

3.10

pigment

addition inert to the ingredients of concrete and intended to provide colour to the concrete

3.11

quality control test

test performed on samples drawn either from continuous production or from a consignment of finished products, to establish whether a batch of products conforms to this standard

DRS 260: 2014


3.12

regular front edge (RF)

edge of a tile (interlocking and non-interlocking) which, by design, has a constant or regularly varying hanging length across the width

3.13

irregular front edge (IF)

edge of a tile (interlocking and non-interlocking) which, by design, has an irregular varying hanging length across the width

3.14

batten lugs

protrusions on the underside of the tile designed to engage over the upper edge of tiling battens

3.15

profile

contour of the top surface of the tile when viewed from the nose end

3.16

rise

vertical distance from the underside of the batten lug to the highest point of the surface profile

3.17

side lap

continuous longitudinal overlap of a tile on its neighbour

4 Symbols

L1 hanging length of a tile (see figure A.1)

L2, L3 hanging edge length (see figure A.1)

Cw nominal cover width of one tile

Cwc cover width closed up value of ten tiles

Cwd cover width drawn out value of ten tiles


d profile depth of a tile (see figure 4)

Fa average transverse strength of tiles

Fi transverse strength of an individual tile

IL interlocking

NL non-interlocking

RF regular front edge

5 Requirements

5.1 Materials and Manufacture

Roofing tiles shall be manufactured from cementitious materials, water, and mineral aggregates with or without the inclusion of other materials.

5.1.1 Cement

The cement used in the manufacture of the tiles shall comply with the requirements of RS EAS 18-1.

5.1.2 Aggregate

Aggregates shall consist of natural sand; crushed or uncrushed gravel, stone, or rock; or a combination of any of these (see RS 373).

5.1.3 Water

Water used in the mixing of the concrete shall be clean and free from impurities that may impair the strength or the durability (or both) of the concrete.

5.2 Hanging length and squareness

5.2.1 The tile hanging length shall be declared in the manufacturer’s technical specification. For tiles with a regular front edge, the values of L1 shall be within ± 4 mm of the manufacturer’s declared value when tested according to A.1.

5.2.2 The squareness for tiles with a nominally constant hanging length, when tested in accordance with A.1, shall be calculated as the difference between values L2 and L3, and shall be not greater than 4 mm.

NOTE Some tiles are designed, for example for aesthetic reasons, with an irregular front edge (IF). In these cases, the

test method and requirements do not apply.

DRS 260: 2014


5.3 Cover width

5.3.1 General

The stated cover width Cw shall be declared in the manufacturer’s technical specification.

NOTE Some tiles are designed, for example for aesthetic reasons, with a random cover width. In these cases, the

requirements specified in 5.3 do not apply.

5.3.2 Interlocking tiles

When tiles are tested in accordance with A.2.1, the average cover width shall be within ± 5 mm of the manufacturer’s declared value.

5.3.3 Non-interlocking tiles

When tiles are tested in accordance with A.2.2, the average cover width shall be within ± 3 mm of the manufacturer’s declared value.

5.4 Flatness

When tiles are tested in accordance with A.3, the gap between any desired contact point and the flat surface shall not exceed 3 mm.

NOTE For some tile patterns, the test method and the requirements in 4.4 are not suitable and do not apply, for

example:

a) the tiles are designed to have less than four desired contact points to a flat surface; or

b) the tiles are designed to be irregular, for example, for aesthetic reasons.

5.5 Mass

The mass of tiles shall be declared in the manufacturer’s technical specification. When tiles are tested in accordance with Annex A, the average mass shall be:

a) manufacturer’s declared mass ± 0.2 kg for tiles with a declared mass not exceeding 2 kg; and

b) manufacturer’s declared mass ± 10 % for tiles with a declared mass greater than 2 kg.

5.6 Fixing holes (where provided)

5.6.1 Fixing holes shall be of an acceptable diameter and shall be positioned within 14 mm - 20 mm of the batten lug(s).


5.6.2 Plain tiles shall have two fixing holes, the centre of each hole being not less than 25 mm and not more than 45 mm from the adjacent side of the tile.

5.6.3 Profiled interlocking tiles shall have at least one fixing hole that is as close as practicable to the longitudinal centre line of the tile.

NOTE It is important that fixing holes be arranged so that a permanent connection between the tiles and the batten

can be achieved.

5.7 Transverse strength

When tiles are tested in accordance with Annex A, (Fa) and (Fi) per millimetre of tile width shall be not less than the appropriate value given in Table 1.

Table 1 — Minimum transverse strength (N) per millimetre of tile width

Interlocking tiles

Profiled Flat

Average

Fa

Individual

Fi

Average

Fa

Individual

Fi

5.00 4.50 4.00 3.50

5.8 Impermeability

When tiles are tested in accordance with Annex A, drops of water shall not have formed on the underside of the roof tiles and there shall be no trace of dampness on the underside of any of the tiles.

5.9 Water absorption

Water absorption, when tested in accordance with Annex A shall not exceed 10.5 % for normal weight tiles (with density greater than or equal to 2 000 kg/km3); 14.5 % for medium weight tiles (with density between 1 500 kg/m3 and 2 000 kg/m3) and 18 % for lightweight tiles (with density less than 1 500 kg/m3).

5.10 Colour

The colour shall be as specified by the purchaser. The exposed surface of each tile shall be reasonably evenly coloured.

5.11 Freedom from surface defects

Roofing tiles shall be shaped during manufacturing by moulding, pressing, or extrusion and shall be acceptably

free from excrescences, depressions and other defects.

DRS 260: 2014


5.12 Surface coating

Any surface coating applied to the tiles shall not contain any material which is deleterious to the materials of which the tile is made.

5.13 Types and dimensions

5.13.1 Types

Tiles shall be of the plain type or the interlocking type, as specified by the purchaser and shall be true to pattern and uniform in shape.

NOTE 1 Various tile patterns are available and the purchaser should consult the catalogues of the manufacturer in this

regard.

NOTE 2 Roofing tiles are generally planar or undulating rectangular shapes available in a variety of cross-sectional areas

profiles, shapes, sizes, surface textures, and colours as may be specified by the purchaser.

5.13.2 Dimensions

5.13.2.1 In the case of interlocking tiles, the size (small, medium A, medium B, or large) shall be as specified by the purchaser and shall be measured to the nearest 1 mm (see table 1).

5.13.2.2 The total variation in dimensions of tiles (length, width, and thickness) shall not be more than ± 5 % from the manufacturer’s designated dimensions.

Table 2 ─ Dimensions of concrete roofing tiles

Nominal Sizes in

mm (minimum) Type

Plain Interlocking

Small Medium A Medium B large

Length 265 380 420 420 430

Width 165 230 280 330 380

Thickness 10 10 10 10 25

Side lap - 25 25 25 35

NOTE Interlocking portion shall have a minimum thickness of 8 mm


6 Compliance and sampling

6.1 Concrete roofing tiles shall be deemed to comply with this standard when the manufacturer can demonstrate that a random sample taken from a production batch in accordance with table 2 satisfies each quality control test requirement.

6.2 Batch shall be deemed to comply with the requirements of the standard if, after inspection and testing of the sample taken, no defective is found.

Table 3 — Sample size for quality control purposes

Tests Batch size (B)

B < 10 000 B > 10 000

Hanging length and

squareness 3 5

Cover widtha ≥ 8 ≥ 8

Flatness 3 5

Mass 3 5

Transverse strength 3 5

Impermeability 16 16

Water absorption 3 5

NOTE a This test is only performed when requested.

6.3 If the results of tests undertaken on the first sample are inconclusive, a second sample shall be taken in accordance with table 3, and shall comply with the acceptance criteria specified in clause 5.

Table 4 — Sample size for quality disputes (retest)

Batch size

(B)

Sample size Acceptance

(maximum number of

failures)

B ≤ 151 3 0

151 < B ≤ 3 200 13 1

3 201 ≤ B ≤ 35 000 20 2

35 001 ≤ B ≤ 500 000 32 3

B ≥ 500 001 50 5

DRS 260: 2014


7 Methods of test

The following tests are required on concrete roofing tiles:

a) hanging length and squareness of regular front edge (RF) tiles (see A.1),

b) cover width (see A.2),

c) flatness (see A.3),

d) mass (see A.4),

e) transverse strength (see A.5),

f) permeability(see A.6),

g) dimension and weight (see A.7),and

h) water absorption.(see A.8)

8 Marking, labelling and packaging

8.1 Products

Concrete roofing tiles complying with this standard shall be legibly and indelibly marked with the name of the manufacturer or trademark or with other means of identification.

8.2 Documents

The following particulars shall be indicated clearly on the delivery note or invoice or supplier's certificate, supplied with the consignment of concrete roofing tiles:

a) the name or trade mark or other means of identification of the manufacturer; and

b) the name and colour of the product.


Annex A (normative)

Concrete roofing tiles-Method of test

A.1 Hanging length and squareness of regular front edge (RF) tiles

Hang the tile at an angle of 20° - 70° on a steel batten (See figure A.1(a)). After having removed any burrs or other irregularities (or both), measure the distance from the top face of the batten to the lower front edge of the tile at the sides (See figure A.1(b)). Record the values L2 and L3 to the nearest millimetre and calculate the value of L1 to the nearest millimetre.

A.2 Cover width

A.2.1 Interlocking tiles (IL)

A.2.1.1 Hang or lay a minimum of ten tiles of the same nominal cover width with their locks fitting well, in the manner specified by the manufacturer.

A.2.1.2 Push the tiles together to their minimum coverage, taking care that the interlocking parts of the tiles do not lift or disengage. Measure to the nearest millimetre and record the closed up value Cwc (See figure A.2 (a)).

A.2.1.3 Pull the tiles apart to their maximum coverage, taking care that the interlocking parts of the tiles do not lift or disengage. Measure to the nearest millimetre and record the drawn-out value Cwd (see figure A.2 (b)).

A.2.1.4 Calculate the average cover width to the nearest 0.1 mm as follows:

𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑐𝑜𝑣𝑒𝑟 𝑤𝑖𝑑𝑡ℎ =𝐶𝑤𝑑 + 𝐶𝑤𝑐

2𝑛 − 2

where

𝑛 is the number of tiles used

A.2.2 Non-interlocking tiles (NL)

A.2.2.1 Hang or lay a minimum of ten tiles of the same nominal cover width on a batten in the manner specified by the manufacturer.

A.2.2.2 Push the tiles together. Measure, to the nearest millimetre, and record the width of the tiles.

A.2.2.3 Calculate to 0.1 mm the average cover width.

DRS 260: 2014


A.3 Flatness

A.3.1 Place the tile on a flat level surface with the nibs projecting, as shown in figure A.3. Hold the tile down to ensure that the head of the tile is in contact with the surface.

A.3.2 Use a steel bar with a diameter of 3 mm or 𝐶𝑊

100 mm to the nearest millimetre, whichever is the greater.

Check whether any gap between the lower front edge of the tile and the measuring surface at any nominal contact point without lifting the tile, is greater than the specified value.

A.3.3 Record the results for each tile tested.

A.4 Mass

Condition the tiles to be tested in their dry state at ambient temperature.

Weigh each tile to at least the nearest 25 g. Record the values measured and calculate the average mass of the tiles in the sample to the nearest 10 g.

A.5 Transverse strength

A.5.1 Conditions of tiles

Store the tiles to be tested at ambient temperature for at least 24 h in such a manner that air is free to circulate around all sides of each tile.

A.5.2 Apparatus

An apparatus that consists essentially of two supports in the form of self-aligning steel bearers (of diameter 40 mm and whose distance apart is adjustable) and another steel bearer (of diameter 40 mm), through which the load is applied by suitable means at midspan, along a line parallel to the supports. The length of each bearer exceeds the maximum width of the tile to be tested.

A.5.3 Procedure

A.5.3.1 Measurement of profile depth, d

If the manufacturer’s declared value of d is less than 20 mm, measure d for each tile in the sample, and calculate the average value for the sample (See figure A.4).

A.5.3.2 Positioning the tile in the machine

A.5.3.2.1 Place the tile to be tested with the top surface uppermost on the lower bearers of the test machine so that the centre line of the hanging length is midway between the two lower bearers (see figure A. 5).


A.5.3.2.2 If the tile is not stable in this position (e.g. the tile rests in or on a water-lock), move the tile in the direction that brings the tile hanging nibs nearer to the bearer by a distance specified by the manufacturer to ensure stable bearing.

A.5.3.2.3 The angle of the upper bearer (loading bearer) in relation to the fixed lower bearer, does not exceed 10°. Use packing pieces with a flat top, as necessary, to achieve this (See figure A.6). The width of the packing pieces does not exceed the diameter of the rounded part of the lower bearers.

A.5.3.2.4 With plain and flat tiles, place an elastomeric pad between the upper bearer and the tile (see figure A.5).

A.5.3.2.5 With profiled tiles, arrange a contoured packing block between the upper bearer and the tile (see figure A.5). Use the contoured packing block made of hardwood or metal or moulded with plaster, which is 20 mm ± 1 mm wide. Where the contoured packing block is made of hardwood or metal, place an elastomeric pad between the contoured packing piece and the tile.

A.5.3.2.6 The length of the elastomeric pad is at least equal to the width of the tile and is not less than 20 mm wide and 10 mm ± 5 mm thick with a hardness of (50 ± 10) Shore A.

A.5.3.2.7 So place the tile that the underlock (if applicable) is not loaded and in such a way that the load can be applied centrally on the cover width (see figure A.6).

NOTE For quality control purposes, the test may be carried out without the use of the elastomeric pad and contoured packing block.

A.5.3.3 Load application

Apply the load through the upper bearer at a rate not exceeding 6 500 N/min until failure occurs.

A.5.4 Recording of test results

Record the maximum load of each tile to the nearest 10 N. When calculating the total load, include the weight

of the packing pieces used on the top surface if they exceed 5 N.

A.6 Permeability

A.6.1 Apparatus

A.6.1.1 The apparatus consists of a rain penetration test rig (see figure A.7) that simulates rainfall on the tiles. The test rig consists essentially of a section of a roof frame constructed at a pitch of 30° and of sufficient area to allow the test specimens (see A.6.2) to be mounted on it.

A.6.1.2 The sides and back of the rig are enclosed and if the rig is used in the open, some form of cover is needed to protect the roof from wind and rain.

A.6.1.3 Access to the underside of the roof is provided for the purpose of observation. Illumination should also be provided.

DRS 260: 2014


A.6.1.4 A sparge pipe is placed over the top of the roof frame to simulate the rain that would run down from higher courses of a full size roof. To simulate direct rainfall, a suitable spray or set of sprays is so placed over the area of the frame that every tile receives an equal volume of water. The flow is monitored by means of flow meters. The simulated rainfall used for the test is 150 mm/h from the sparge pipe and 75 mm/h from the spray. The flow rate required from the spray to achieve the simulated rainfall for a given roof area is calculated as follows:

𝑄 = 1.25 × 𝐴

where

𝑄 is the flow rate in litres per min (L/min); and

𝐴 is the actual roof area, in square metres.

A.6.1.5 The flow rate from the sparge pipe is double that from the spray.

A.6.1.6 A tank having a capacity of at least 100 L.

A.6.1.7 A suitable pump, capable of delivering the required flow rates.

A.6.2 Test specimens

Take 16 tiles from the sample. Ensure that the tiles are not damaged in any way.

A.6.3 Procedure

A.6.3.1 In the case of interlocking tiles, lay the tiles on the test rig in a 4 × 4 arrangement with a head lap of 75 mm. In the case of plain tiles, lay the tiles in a similar arrangement but with a head lap of 65 mm.

A.6.3.2 Start the flow of water and ensure that the required flow rate is achieved. Stop the flow after 2 h and inspect the underside of the tiles.

A.7 Dimensional tolerance and weight

A.7.1 Dimension

The total variation in dimensions of tiles (length, width, and height shall not be more than ± 5 % from the manufacturer’s designated dimensions.

A.7.2 Weight

The total variation in weight of tiles shall not be more than ± 5 % from the nominal weight specified by the supplier.


A.8 Water absorption

A.8.1 Apparatus

Unless specified otherwise in the appropriate annex, the balance used shall be readable and accurate to 0.1 % of the smallest specimen tested.

A.8.2 Test specimens

A.8.2.1 Unless specified otherwise in the applicable annex, test three specimens in absorption.

A.8.2.2 Unless specified otherwise in the applicable annex, tests shall be performed on full-sized units or specimens saw-cut from full-sized units. Calculated values for absorption and density of reduced-size absorption specimens shall be considered as representative of the whole unit.

A.8.2.3 When test specimens are saw-cut from full-sized units, the test specimen shall have an initial weight after cutting of no less than 20 % of the initial received weight of the full-sized unit.

A.8.3 Procedure

A.8.3.1 Saturation

A.8.3.1.1 Immerse the test specimens in water at a temperature of 15 to 27 °C for 24 h - 28 h such that the top surfaces of the specimens are no less than 150 mm below the surface of the water. Specimens shall be separated from each other and from the bottom of the immersion tank by at least 3 mm, using wire mesh, grating, or other spacers so that not more than 10 % of the surface area of the specimen is in contact with the spacer.

A.8.3.1.2 Weigh the specimens while suspended by a metal wire and completely submerged in water and record Wi (immersed weight). Remove from the water and allow to drain for 60 s ± 5 s by placing them on a 10mm or coarser wire mesh, removing visible surface water with a damp cloth; weigh and record as Ws (saturated weight).

A.8.3.2 Drying

Subsequent to saturation, dry all specimens in a ventilated oven at 110 °C ± 5 °C for not less than 24 h and until two successive weighings at intervals of 2 h show an increment of loss not greater than 0.2 % of the last previously determined weight of the specimen. Record weight of dried specimens as Wd (oven-dry weight).

A.8.4 Calculations

Calculate absorption in % as follows:

𝑊𝑆−𝑊𝑑

𝑊𝑑

× 100

where

DRS 260: 2014


𝑊𝑆 is saturated weight of specimen, kg; and

𝑊𝑑 is oven-dry weight of specimen, kg

(a)

(b)

Figure A.1 — Hanging length and squareness of regular front edge (RF) tiles

( b )


(a)

(b)

Figure A.2 — Cover width

Figure A.3 — Flatness

DRS 260: 2014


Figure A.4 — Measurement of profile depth

Figure A.5 — Positioning the flat tile in the machine


Figure A.6 — Testing with contoured packing blocks

DRS 260: 2014


Rear view sectional side view of the rig

Figure A.7 — Permeability test rig (Simulated rainfall test)

DRS 260:2014

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