Artificial Weathering using a Fluorescent Lamp Source


ASTM G154
ASTM D 4587
BS EN ISO 11507 : BS 3900-F16

 QUV/Spray Weatherometer

Scope and Field of Application

These are all methods for determining the resistance of materials to artificial weathering.

ASTM G 154 deals with the testing of non-metallic materials.

ASTM D 4587 deals with the testing of paint and related coatings.

BS EN ISO 11507 and BS 3900-F16 are alternative names for the same method which deals with the testing of paint and related coatings.

This means that ASTM G 154 can be used both for paints and other organic materials such as polymers. The other two methods should only be used when testing paint and related coatings.

All three methods define identical equipment: the main difference between them is in the operating conditions.They aim to replicate the degradation caused by sunlight and rainfall. If you are more concerned with colour fading of surfaces exposed to sunlight indoors, please refer to our Assessment of Lightfastness page.

Like all laboratory tests, the methods described here have their advantages and limitations and these are summarised, in general terms, on our Testing Paints for Resistance to Weathering page.

The main disadvantages of the methods are:-

The main advantages methods are:-

In addition to these methods, you may also wish to consider the advantages and limitations of the enclosed carbon arc and the xenon arc tests.

There are no pass/fail criteria defined in the standards. This is a matter of agreement between the parties concerned.

The actual standards are copyright-protected documents and we are not able to provide you with copies. If required however, you can easily obtain copies from the American Society for Testing and Materials or the British Standards Institution.

 

Summary of Methods

All the standard methods listed below allow for the use of two different types of instrument. We have both types

The basic instrument is constructed so that test panels are exposed to radiation from a bank of fluorescent lamps and mounted above a heated water container. The rear surfaces of the panels are air-cooled and consequently water condenses on the test surfaces during periods when the lamps are switched off.

The second type of instrument has all the features of the basic equipment but, in addition, you have the options of spraying the test samples with water and adjusting and controlling the UV light intensity. This instrument can be used in three modes:-

The condensation-only mode has been used for many years but there is increasing interest in the use of sprayed water and the spray-only mode is designed to mimic the both the erosive and the cooling action of rain. The spray-and-condensation mode is regarded as being especially appropriate for the testing of wood coatings.

Our instruments are manufactured by Q-Panel Lab Products and their website includes full details of all their products.

 

ASTM G154

The standard defines eight different exposure cycles in terms of lamp type, irradiance, black panel temperature and the periods of illumination and wetness. The standard also states which cycles have been used for testing surface coatings and plastics in general, automotive paints, roofing materials and wood finishes. In fact any exposure conditions can be used provided they are detailed in the test report. We will be pleased to advise on the most appropriate conditions for testing your materials.

No information is given in the standard relating the number of hours under test to the number of years natural exposure. In our experience when exterior alkyd gloss paints are exposed in the test cabinet for 1,000 hours they undergo a loss of gloss equivalent to 1 year of natural exposure in Southern England. The cabinet exposure conditions were:-

ASTM D 4587

This standard deals with the selection of test conditions, the preparation of test specimens and the evaluation of results. It is intended to be used in conjunction with ASTM G 154 or BS EN ISO 11507:BS 3900-F16.

BS EN ISO 11507 : BS 3900-F16

The equipment used is identical to that specified for ASTM G154. The only significant difference is that BS EN ISO 11507 / BS 3900-F16 only defines one set of exposure conditions for use in the condensation mode. The conditions are a cycle of four hours at 60° C (dry) followed by four hours at 50° C (wet). The BS standard does not define any cycles for the spray mode. These are a matter for agreement between interested parties.

 

Sample Requirements

The requirements are the same for all three methods.

Ideally we require 150 x 75 mm panels not more that 5 mm thick, although we can accommodate a limited number of 150 x 100 mm panels provided they are less than 5 mm thick. If you have smaller samples you can fix them to 150 x 75 mm panels provided the overall thickness does not exceed 5 mm. If your samples are larger, you may wish to consider the enclosed carbon arc method.

We recommend running samples in triplicate.

If you wish, we can prepare the test panels. The quantity of liquid paint we needs depends on the method of application. We will be pleased to advise you regarding our requirements.

 

Accreditation

PRA is accredited to ISO 17025 by the United Kingdom Accreditation Service (UKAS), to carry out these tests.

 

Please contact Peter Collins for further details.

 

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