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ASSESSMENT CRITERIA
ACTMAP 1 PART 3: TEST METHODS
Performance tests for the assessment of products used in roof waterproofing systems are described in this chapter.
Various applications, in terms of types of support, methods of laying and the types of protection available, are taken into account so that the tests represent the worst possible situation for the particular product. In cases where waterproofing materials are required to be tested on typical substrates, the substrates must be representative of those on which the waterproofing is used in practice.
In some cases the ultimate properties of a waterproofing system will not be reached until curing has occurred. In general, unless special precautions are taken on site, a system must have cured sufficiently in 4 to 6 hours under the most adverse installation conditions if it is to resist the normal changes in climatic conditions (eg frost conditions, precipitation, wind suction and thermal movement of the supporting substrate).
To establish a system’s vulnerability to these conditions, specimens may be subjected to certain preliminary tests after being conditioned for 6 hours at the lowest temperature at which installation may take place. The specimens should also be tested after being conditioned for 7 days at 23 ±2 °C and 50 ±5 % relative humidity.
Where hot bitumen is used as the bonding system, all tests can be carried out 24 hours after the specimen has been prepared.
Unless otherwise stated all tests will be carried out at 23 ±2 °C and 50 ±5 % relative humidity.
GENERAL TESTS
Tests for behaviour in fire
Any fire tests that are considered to be necessary (eg to determine combustibility) should be carried out in accordance with the relevant deemed-to-satisfy rules given in SABS 0400, The application of the National Building Regulations.
Test for resistance to pull-off under suction
The test may be applied to:
- flexible sheet membranes that are
- partially bonded
- mechanically fixed
- in situ-applied, continuous membranes.
Loose-laid membranes with heavy protection need not be tested for resistance to pull-off.
Note: Peel tests might indicate which waterproofing systems, substrates and methods of application are sensitive to wind uplift. They may be used to determine a suitable programme of pull-off tests under suction.
Apparatus
A box measuring 2 m x 1 m x 0,25 m deep, consisting of a base and four sides designed to withstand a vacuum of 5 kPa without deformation. Viewing windows of transparent acrylic sheet are incorporated in the two short ends of the box.
A lid which can be hermetically sealed to the box.
A connection from the box to equipment for applying suction forces to the specimen; the forces are increased progressively.
Test specimens
A specimen of the roofing system measuring 2 m x 1 m is bonded or fixed to a typical support (concrete, timber, thermal insulation, etc) laid in the bottom of the box. If the support does not possess the weight and rigidity required to resist the suction, it is fixed to the base of the box. The test is carried out with a longitudinal joint (2 m long x 10 mm wide) between two support elements. Three 25 mm diameter holes provide vents between the joint and the external atmosphere in the box. One hole occurs at the center and one on either side, 500 mm from the center, in line with the joint.
The specimen is either bonded or mechanically fixed to the support in accordance with the manufacturer’s instructions and the edges around the perimeter of the box are sealed with a flashing to provide an airtight seal.
When a fully bonded system is to be tested, the specimen should be bonded to the support except at the joint. A fold 30 mm wide and 10 mm high is made in the specimen material over the joint for its full length by using a shaped timber batten which is later removed.
Method
The box is attached to the source of the vacuum and the following pulsating suctions are applied so that the maximum load lasts for at least 1 second with a maximum pulse time of 3 seconds:
- 2000 cycles from 0 to 0,2 z
- 500 cycles from 0 to 0,5 z
- 50 cycles from 0 to 1,0 z
where p z is the characteristic wind pressure determined according to SABS 0160. The value of p z will be calculated for the most onerous conditions (in terms of height of building, terrain category, regional basic design wind speed, altitude and local external pressure coefficients) to which the waterproofing system might be exposed.
Note: A value of pz = 2,5 kPa would cover 90 % of the waterproofing situations which may be encountered. Only in a few cases would higher pz values be obtained, with exceptional cases giving values of the order of 5,0 kPa.
Observations
The behaviour of the specimen is observed through the window during each of the three stages. If failure occurs, the suction pressure and number of cycles are recorded.
After the test, the specimen is carefully examined and the mode of failure recorded.
The following modes of failure are possible for bonded systems:
- delamination within the waterproofing membrane or system
- failure at the waterproofing/adhesive interface
- cohesive failure in the adhesive layer
- failure at the adhesive/support interface
- cohesive failure within the support.
The following modes of failure are possible for mechanically fixed systems:
- delamination within the waterproofing membrane or system
- tearing of the waterproofing material at the point of fixation
- pull-out of the mechanical fixing from the support.
Test for resistance to peel
This test is applicable to products used in all waterproofing systems. The test
- allows extrapolation from the pull-off under suction test to all supports where the resistance to peel is superior to that obtained on the support used in the pull-off under suction test;
- can be used to test the bond achieved at upstands;
- can be used to compare the effectiveness of different adhesives;
- can be used to assess bonding agents which may be sensitive to ageing, heat and humidity.
Note: Where the edges of the waterproofing system are not exposed in practice (ie they are mechanically fixed or held down by flashings), this test may not be necessary.
Apparatus
Tensile test machine (eg instron)
Peel test frame.
The apparatus consists of a peel test frame which can move while maintaining an angle of peel of 90 ° (±5 °). A rigid steel frame is mounted on the moving crosshead of the tensile test machine and a carriage on which the specimen is mounted is located on the frame with free-running bearings. The motion of the crosshead of the tensile test machine is transferred to the carriage in the ratio: 1:1 with a wire and pulley arrangement. A counterweight is fitted to return the carriage to the start position and to maintain the tension in the wire.
Test specimens
Specimens of the roofing system are laid on substrates that may typically be used in practice, and approximately 300 mm x 300 mm. A specimen 50 mm longer than the substrate is fully bonded to it except at the projecting end where the specimen is unbonded for a distance of 50 mm to facilitate the start of the peel. If the properties of the specimen in its length differ from those in its width, it must be tested in both directions.
The specimen is cut through to the substrate along its length or width so that three 50 mm wide peel strips are provided.
Method
Three specimens are peeled, one at a time, at a rate of 100 mm/min.
Observations
The maximum peel strength and the mean peel strength are recorded. The position and type of failure is noted (ie adhesion, cohesion, delamination, etc).
Note: This test may be carried out under different temperature/humidity conditions.
Test for resistance to water pressure
This test is used to check the resistance of the waterproofing membrane to water under pressure. It may be applied to products used in all waterproofing systems.
Apparatus and Method
A circular metal gland, with a 60 mm diameter aperture is connected to an open-ended pipe which rises to a height of 6 m. Instead of using a 6 m pipe, the test apparatus can be pressurized to 60 kPa.
A circular rubber washer fits onto the face of the gland and a specimen of the membrane is cut and fitted over the washer, covering the aperture.
A wire mesh the same size as the roofing specimen is placed over it and another rubber sealing washer fitted.
A gland of the same size as the base is fitted and the complete assembly loosely bolted together.
Water is supplied until it flows out from under the specimen, the assembly is then clamped tight and the water flow continued until it overflows from the 6 m pipe. The water supply is turned off and the specimen examined throughout a 24 hour period for any leakage.
Three specimens are tested.
Test for resistance to thermal shock
This test may be applied to sheet membranes that are fully bonded, partially bonded or mechanically fixed and to in situ-applied continuous membranes.
This test is not necessary for membranes that are to be used under heavy protection.
Apparatus
As for ‘Test for resistance to pull-off under suction’ plus a means of heating the upper surface of the membrane with radiant heat.
Test specimens
As for test for resistance to pull-off under suction.
Method
The upper surface is heated by radiant heat to a temperature of 80 ±3 °C. The heating-up time should be 30 ±5 minutes and the specimen is held at this temperature for 1 hour when the surface is sprayed with water (temperature 15 °C – 20 °C) for ten minutes or until ambient temperature is achieved. The heating and cooling cycle is repeated daily at least ten times. If there is evidence of continuing movement or deterioration after ten cycles the cycling should be continued until equilibrium is reached. Finally, the test for resistance to wind suction is carried out (refer to test for resistance to pull-off under suction).
Observations
After each cycle the specimen is examined for signs of failure (ie loss of adhesion, movement of the material, failure of joints, blistering, etc). Very often minor blistering of the surface occurs in the first few cycles, and subsequently disappears. These are not considered important unless they cause a significant loss of adhesion.
There should be no significant change in the resistance to wind suction.
Tests for dimensional stability
These tests are applicable to products used in all waterproofing systems.
Test for unrestrained shrinkage
Apparatus
Optical or mechanical device with a measuring range of up to 300 mm, suitable for measuring to an accuracy of within 0,05 mm
Six mm thick glass plate, 5 mm less than test specimen size in both directions
Dry ventilated oven, accuracy 2 °C.
Test specimens
Three specimens of the system, each at least 200 mm x 200 mm.
Method
The specimens are coated with talc on both faces, placed on a smooth support and weighed down with the glass plate. The dimensions are measured at three points crosswise and lengthwise. The mean value is calculated for each direction.
The specimens are placed on aluminium foil inside the oven and conditioned at 80 ± 3 °C for 6 hours.
They are cooled for 18 hours on a smooth support and the dimensions are measured as previously described.
The heating cycle is repeated until consecutive measurements do not differ by more than 0,1 % from the original specimen size.
Observations
The mean shrinkage is recorded as a percentage of the initial dimensions in each direction.
Test for restrained shrinkage
This test is applicable to products used in all waterproofing systems.
Note: The test is carried out on bonded specimens and on loose-laid specimens under heavy protection. The decision on whether to carry out this test or not depends on the result of the free shrinkage test according to the requirements given for dimensional stability in Part 4.
Principle of the test
The test consists of subjecting specimens of the waterproofing system to cyclic variations of temperature. The dimensional changes of the waterproofing are measured as a function of the number of temperature cycles.
Apparatus
The apparatus is shown diagrammatically in the figure.
A rigid is maintained at a constant temperature by circulation of water. A thermal insulant is stuck on to the support and the waterproofing system to be tested is placed on the insulant. Reference points are fixed on the upper surface at the two extremities of the sample. These reference points are opposite to the fixed reference points. The distance between the two is measured to an accuracy of 0,1 mm with a suitable instrument such as an optical micrometer. An infra-red heater is used to heat the surface of the waterproofing system. An automatic system of continuous control and programming the heating and cooling cycles is required.
Test specimens
Three specimens of the system, each at least 300 mm x 300 mm.
Method
Three specimens measuring 300 mm x 300 mm are cut from the waterproofing and are applied to a specified support by the method recommended by the manufacturer (loose-laid with gravel, bonded, etc).
The specimens are provided with metal reference points in both directions and the distance between them is measured before and after cycling.
The specimens are subjected to cycles of heating and cooling. The surfaces are maintained at 80 ±3 °C during the heating cycle and at 20 ±3 °C during cooling.
Each cycle lasts for 24 hours and consists of:
- 3 hours at 80 °C
- 2 hours at 20 °C
- 3 hours at 80 °C
- 16 hours at 20 °C
Observations
The change in dimensions of the specimens is measured after each cycle.
The total variation is plotted against the number of cycles executed.
The test is continued until stabilisation occurs.
Test for resistance to sliding
This test is only necessary for flexible sheets that are to be used in systems on sloping roofs and is not necessary when mechanical fixing at the top of the roofing sheets is provided, or in the case of upstands that are mechanically fixed, but not bonded.
Apparatus
A source of radiant heat.
Test specimens
The system is bonded to a typical substrate, 300 mm x 300 mm, representative of that used in practice for the waterproofing system.
Method
The specimen is inclined at the maximum intended slope and the entire surface of the specimen is maintained at 80 ±3 °C for 7 days. Any movement is measured.
Test for resistance to cyclic fatigue
This test is applicable to products used in all waterproofing systems.
The results of the tests are applicable to both partially and fully bonded waterproofing system to determine the effect of movements in joints (ie expansion joints, cracks in the substrates, joints between precast panels, beams, etc).
The test is always carried out with a fully bonded test piece on a concrete substrate.
Apparatus
The apparatus consists of two metal plates to which two concrete slabs supporting the specimens are fixed; the ends of the slabs abut each other. The joint between the two slabs can be opened and closed at a rate of 16 mm/hour.
Preparation of the concrete slabs
The mix for the slabs shall be as follows:
1 ordinary Portland cement : 2 sand (5 mm and finer) : 4 course aggregate consisting of 1,33 parts 10 mm and 2,67 parts 20 mm and with a water : cement ratio of 0,6.
The mould should be of steel, coated with mould oil, and the corners of the slab to which the roofing is to be applied shall be formed by the bottom and side of the mould.
The concrete is vibrated to full compaction.
Usual concreting practice should be followed as regards demoulding and curing.
Test specimens
Specimens of the waterproofing system each measuring 300 mm x 50 mm, are bonded to the concrete slabs in their closed position (1 mm gap between slabs) with the middle of the long dimension positioned over the joint. The specimens are prepared by applying the waterproofing system in accordance with the manufacturer’s specifications.
Three specimens are tested after conditioning at 23 ±2 °C for seven days and a further three specimens after conditioning at 80 ±3 °C for 28 days.
Method
The apparatus is placed in a controlled environment at temperatures of 20 °C, 10 °C and 0 ±2 °C. Other test temperatures may be used as appropriate. The initial gap between the slabs is 1 to 2 mm depending on the magnitude of the anticipated movement in service. The joint is opened and closed according to the chosen amplitude, either –0,5 to 0,5 mm (total 1 mm) or –1 to 1 mm (total 2 mm). The number of cycles is 500 and 200 for new and aged materials, respectively.
Observations
The apparatus is stopped after every 50 cycles and the specimens are examined for loss of waterproofness due to cracking, tearing, splitting or other types of failure, as well as for total loss of adhesion. Signs of minor buckling or partial loss of adhesion are also noted and the effects interpreted. The amount of movement that is accepted before failure occurs is noted.
Membrane classification
Three classes of resistance of cyclic fatigue are envisaged:
Classification: Extension without failure at different temperatures (after 500 cycles for new material and 200 cycles for aged material)
M1: up to 1 mm movement (0,5 to -0,5) at 20 °C
M2: up to 1 mm movement (0,5 to –0,5) at 0 °C
M3: up to 2 mm movement (1 to –1) at 0 °C
Note: The product, when used in a particular waterproofing system, is classified in accordance with the maximum movement that it can accept at the lowest temperature, ie M3 would be better than M1.
Test for resistance to static puncture
General
Applicable to products used in all waterproofing systems.
Apparatus
A steel ball 10 mm in diameter
A means of applying constant loads of from 50 N to 250 N, in increments of 10 N, 20 N or 50 N.
Test specimens
The specimens of the waterproofing system, each at least 100 mm x 100 mm, are tested on substrates consisting of concrete and/or expanded polystyrene (25 ±2 kg/m3).
Method
The steel ball is used to load each specimen with a constant load for 24 hours. If perforation does not occur within 24 hours the load is increased in stages of 10 N, 20 N or 50 N at different positions, until the waterproofing is perforated within 24 hours.
Observations
Each specimen is examined visually and may be tested using a 50 mm water column. If leakage occurs the specimen is deemed to be perforated. The mean load which perforates the waterproofing system is recorded.
Classification
Four classes of resistance to static puncture, designated L1 to L4 are envisaged:
| Classification |
Failure load (N) |
| L1 |
less than 50 |
| L2 |
50 to 149 |
| L3 |
150 to 249 |
| L4 |
250 or more |
Tests for resistance to dynamic puncture
French falling arm test
This test is applicable to products used in all waterproofing systems.
Method
The test method is given in Norme Francaise NF P 84-353, Essai de Poinconnement Dynamique, (Dynamic puncture test), November 1983.
In this test, the puncture apparatus consists of a rotating (falling) arm with a prism on the end. This prism hits the specimen with a constant surface area of 50 mm by 2 mm. The length of the rating arm is constant, 510 mm, whereas the mass of the prism is variable. Thus, a variable impact energy is delivered at a constant speed. The levels of impact energy employed may vary from 10 to 50 Joules (J).
Test specimens
Three specimens of the waterproofing system are tested on substrates consisting of concrete and/or expanded polystyrene (25 ±2 kg/m3); other substrates may be used instead, depending on the manufacturer’s specification.
Observations
The specimens are examined visually and may be tested for watertightness by using a 50 mm water column. The impact energies at which the specimens are perforated, are recorded.
Classification
Four classes of resistance to dynamic puncture, designated D1 to D4 are envisaged:
| Classification |
Failure load (Joules) |
| D1 |
less than 10 |
| D2 |
10 to 19 |
| D3 |
20 to 39 |
| D4 |
40 or more |
Gardner impact test
This test is applicable to all waterproofing systems.
Apparatus
Gardner impact tester.
Test specimens
Three specimens of the waterproofing system, each at least 200 mm x 200 mm, are applied to the substrates by the method recommended by the manufacturer. The test is carried out on at least two substrates: a concrete slab and expanded polystyrene (25 ±2 kg/m3).
Method
The apparatus is placed on top of the test specimen. A mass with a 12,7 mm diameter steel ball mounted at the bottom is dropped from different heights onto the specimen which is clamped over a hole in a base plate directly below the falling mass (the hole may be 14 mm, 18 mm or 22 mm in diameter, depending on the thickness of the specimen). The minimum height required to puncture the specimen is determined and the impact energy (mass x height) is calculated.
Observations
The specimens are examined visually and may be tested for watertightness by using a 50 mm water column. The mean impact energy at which the specimens are punctured is recorded.
Classification
Four classes of resistance to dynamic puncture, designated G1 to G4 are envisaged:
| Classification |
Failure load (Joules) |
| G1 |
less than 1,5 |
| G2 |
1,5 to 7,4 |
| G3 |
7,5 to 14,9 |
| G4 |
15 or more |
Test to measure permeability to water vapour
General
This test is applicable to products used in all waterproofing systems.
Apparatus
Room/chamber with a controlled temperature and relative humidity of 23 ±2 °C and 50 ±5 %.
Cylindrical test containers with a diameter of 60 mm – 100 mm and a height of 15 mm – 30 mm.
Balance: range 200 g, accuracy 0,001 g.
Test specimens
Three specimens with an exposed test area of not less than 60 mm in diameter (to fit the containers used).
Method
The "water method" as described in ASTM E96 – 80 is followed. The test container is filled with distilled water to the level specified. The specimen is then sealed to the top of the container and placed in the temperature and humidity controlled room/chamber until a uniform loss in mass is observed at six consecutive time intervals which indicates that a steady state of vapour flow exists. For low permeability materials, it may take longer than 30 days to reach such a steady state.
Observations
The result should be expressed in g/m2 per day.
Test for resistance to hail
Applicable to products used in all waterproofing systems without heavy protection.
Apparatus
Hail gun
Test specimens
Three specimens of the roof waterproofing system are applied to the substrates by the method recommended by the manufacturer (each specimen must be at least 500 mm x 500 mm). The specimens are tested on typical substrates as specified by the applicant.
Method
The hail gun is used to fire roughly spherical ice missiles (artificial hailstones) onto the test specimen. The hailstones are fired normal to the plane of the specimen at impact energies of 5 Joules, 10 Joules and 30 Joules, 5 times at evenly distributed points for each energy value, or until perforation of the test specimen occurs.
Observations
The specimen is examined visually and the impact energy at which the waterproofing is perforated, is recorded.
Membrane classification
Four classes of resistance to hail damage, designated H1, H2, H3, and H4 are envisaged:
| Classification |
Intensity of hall storm |
| H1 |
mild |
| H2 |
moderate |
| H3 |
severe |
| H4 |
very severe |
H1: Perforated by 5 Joules impact
H2: Not perforated by 5 Joules impact but perforated by 30 Joules
H3: Not perforated by 10 Joules impact but perforated by 30 Joules
H4: Not perforated by 30 Joules impact.
ADDITIONAL TESTS FOR SINGLE LAYER WATERPROOFING SYSTEMS
The tests are applicable to products used in all waterproofing systems.
Test for resistance to leakage at joints
Apparatus
Container with a flange with an overall area of 300 mm x 300 mm, provided with a clamping device and a compressed air supply.
Test specimens
Three specimens each 300 mm x 300 mm, including a joint.
Method
The specimen is fixed to the flanges of the container and a seal is used to ensure watertightness. The joint is wetted with a soap solution. An air pressure of 10 kPa is introduced into the chamber and maintained for 30 minutes.
Observations
No leakage should occur during test, as indicated by the absence of soap bubbles.
Test for tensile strength (shear) of joints
Apparatus
Tensile testing machine.
Test specimens
Five specimens each consisting of two strips measuring 150 mm x 50 mm with a joint, bonded with the amount of overlap specified in the applicant’s technical specification.
Method
The two ends of the specimens are secured in the jaws of the machine and a tensile stress applied at a rate of 200 mm/minute until the specimen breaks.
Observations
The maximum load and mode of failure (loss of adhesion, cohesion, break of the sheet) are recorded.
The mean of the maximum stresses obtained for the five specimens is calculated in N and the tensile strength is expressed in MPa.
Behaviour of joints due to ageing on exposure to elevated temperature
Apparatus
Ventilated oven suitable for maintaining a temperature of 80 ± 3 °C.
Test specimens
As described in test for resistance to leakage at joints and test for tensile strength of joints above.
Method
The specimens are conditioned in the oven for 28 days at 80 ± 3 °C. The specimens are then conditioned for 24 hours at 23 ± 2 °C and 50 ± 5 % relative humidity. The specimens are subjected to the tests described in test for resistance to leakage at joints and test for tensile strength of joints and the observations are recorded.
Behaviour of joints due to ageing on exposure to water
Apparatus
Water bath with heating element suitable for maintaining a temperature of 60 ± 3 °C.
Test specimens
As described in test for resistance to leakage at joints and test for tensile strength of joints above.
Method
The specimens are immersed in water at 60 ± 3 °C for seven days. The specimens are then conditioned for 24 hours at 23 ± 2 °C and 50 ± 5 % relative humidity. The specimens are subjected to the tests described in test for resistance to leakage at joints and test for tensile strength of joints above and the observations are recorded.
ADDITIONAL TESTS RELATING TO THE HANDLING OF THE WATERPROOFING MATERIALS ON SITE
These tests are applicable to products used in all waterproofing systems.
Test for resistance to tearing
Apparatus
Tensile testing machine
Test specimens
Five specimens of each material.
Method
In the axis of a 200 mm x 50 mm specimen, a 3 mm diameter hole is made 50 mm from one end. A 2,5 mm nail is placed in the hole and fixed to the lower jaw of the testing machine with a stirrup. The other end of the test sample is fixed in the upper jaw and the machine operated at a rate of 100 mm/minute.
Observations
The maximum force required to tear each specimen is recorded and the mean maximum force for all specimens is calculated in N.
Test for low temperature flexibility
Apparatus
Cold room with adjustable temperature from 5 °C downwards, to an accuracy of 1 °C.
Cylindrical mandrel 20 mm diameter.
Test specimens
Five strips of material each 250 mm x 50 mm long.
Method
The test specimens and the mandrel are conditioned for 2 hours in a cold room.
After conditioning, the specimens are rolled onto the mandrel within 5 seconds.
Observations
The lowest temperature that does not cause any cracking of the material, is recorded. This temperature is determined by reducing the temperature in 5 ° intervals from 5 °C (to an accuracy of 1 °C).
Unrolling test at low temperature
Note: Not applicable to in situ liquid-applied systems.
Apparatus
Cold room with adjustable temperature from 5 °C downwards, to an accuracy of 1 °C.
Test specimen
A roll of material as supplied by the manufacturer.
Method
The roll of material is exposed to 0 ± 1 °C for 24 hours; on removal from the cold room it is immediately unrolled in approximately 15 seconds onto a flat surface.
Observations
The material is examined for evidence of cracking or tearing.
IDENTIFICATION TESTS
The specific ACTMAPs will give the identification tests for each family of waterproofing products. Until these are available, reference may be made to the following list (the list is indicative only, not restrictive, and some tests may not be applicable).
Sheet materials and in situ-applied membranes (where applicable)
Dimensional and mass characteristics
length
width
thickness
mass
density
Mechanical characteristics
tensile strength
tear strength
elongation at break
load at a given elongation
elastic recovery
low temperature flexibility
resistance to blistering
puncture resistance
impact resistance
Other characteristics
shrinkage on heating and weathering
softening point
ash content
moisture absorption.
Adhesives
Specific gravity
Viscosity
Dry extract
Ash content
PH.
Strips and reinforcement
Jointing strips and other materials - as for sheet materials and in situ-applied membranes.
DURABILITY TESTS
The specific ACTMAPs will give the necessary durability tests for each family of waterproofing materials.
For products for which no specific Directives have been established, reference may be made to the aspects set out below.
Note: Durability tests should be carried out so that a curve of change in physical characteristics against time exposed to an aggressive agency can be plotted. The time scale needs to be long enough to establish the trend of the curve. The aggressive agencies can only be decided on the basis of the composition of the material. In some circumstances, particularly with mixed polymers, a period of natural exposure of not less than one year but preferably a longer period, will be required to make a more reliable durability assessment.
In assessing the durability of roofing materials against the action of radiation (heat and ultra-violet) the effect of any protective layer must be taken into account.
Site-applied thin coatings such as paint or chippings that in general lose their protective function rapidly and have to be replaced, should be ignored in the durability assessments.
List of durability tests (not necessarily compulsory or restrictive):
UV radiation (Xenon lamp)
Heat ageing
Ozone test
Oxidation test
Water immersion
Chemicals
Where applicable, the characteristics listed below should also be determined on specimens that have been:
- naturally exposed, for between 1 and 2 years
- exposed to 80 ± 3 °C, for periods up to 56 days
- artificially exposed in a weatherometer for 1 000 hours.
(a) tensile strength
(b) elongation at break
(c) tear strength
(d) impact resistance
(e) dimensional stability
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