Resistance to Sulphur Dioxide


BS 3900-F8
BS EN ISO 3231
ISO 3231
DIN 50018

sulphur dioxide test cabinet

Scope and Field of Application

These tests are designed to measure the resistance of a coating to a humid atmosphere containing sulphur dioxide.

Like all laboratory tests, the methods described here have their advantages and limitations and these are summarised on our Testing Paints for Anti-Corrosive Properties page.

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 either the British Standards Institution. or the Deutsches Institut für Normung.

 

Summary of Methods

The test panels are mounted in a cabinet above a heated aqueous solution of sulphur dioxide. Each test cycle consists of 8 hours exposure followed by 16 hours storage with the heater switched off and the cabinet open to the atmosphere.

We offer two test methods:-

 

Test Summary
BS 3900-F8 which is identical to BS EN ISO 3231 and ISO 3231 The concentration of the solution is either 0.2 or 1.0 litre of sulphur dioxide in 2.0 litres of water. Other concentrations can be used if all parties agree. The temperature of the solution is 40°C and the total area of the panels under test should be 0.5 square metres.
DIN 50018 The only differences between this test and BS 3900 Part F 8 / BS EN ISO 3231 is that in the DIN 50018 test, the sulphur dioxide concentration is restricted to 1.0 or 2.0 litres and a calibration procedure is specified.

The total surface area exposed is specified since it can affect the severity of the test. Increasing the surface area of test samples reduces the available sulphur dioxide per unit area and consequently reduces the severity of the test. The converse is also true.

The test panels are not normally scribed and, in our opinion, a coating with good sulphur dioxide resistance will show no apparent change or substrate corrosion after 10 cycles exposure to a 2.0 litre concentration. The best coatings currently available will provide this degree of protection for more than 20 cycles at this concentration.

The test is also used to measure the corrosion resistance of galvanised and plated metal items..

 

Sample Requirements

The requirements are the same for all the tests. In order to obtain a total test area of 0.5 square metres, we require 16 coated panels 150 x 100 mm. The substrate should be one that is appropriate to the type of coating being tested.

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.

 

Back to Paint Testing Laboratory Page

Back to Testing Paints for Anti-Corrosive Properties Page

Back to top of page