Country/Industry/Company of Origin: Europe

ISO11997-1 Cycle A

Paints & varnishes – determination of resistance to cyclic corrosion conditions, Part 1: wet(salt fog)/dry/humidity

This test method has been found to be useful for comparing the relative resistance to corrosion of paints, varnishes and similar materials, when exposed to a simulated aggressive outdoor environment, such as a marine environment. It is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.

3 different test cycles are defined within this test method, which are referred to as Cycle A, Cycle B & Cycle C.

Cycle A is based upon test CCT-4. Please see elsewhere in this document for details of CCT-4. This test method has been shown to correlate well with natural exposure for thermosetting paints. The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Cycle B is based upon test VDA 621-415. Please see elsewhere in this document for details of VDA 621-415. This test method has been shown to correlate well with natural exposure for thermosetting paints in vehicle corrosion. The number of cycle repeats is to be sufficient for 840 hours total test time, unless otherwise agreed.

Cycle C has been developed in the UK for use with water soluble and latex paint systems, and has been shown to correlate well with natural exposure. Cycle C test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of the following repeating cycle. 210 minutes exposure hours exposure to a continuous indirect spray of salt water solution, which falls-out on to the specimens at a rate of 2.0 to 4.0ml/80cm²/hour, in a chamber temperature of +25C. This is followed by 210 minutes exposure to an air drying climate at +40C (humidity unspecified). This is followed by 1470 minutes exposure to a controlled humidity climate of 75%RH at +40C. This is followed by 102 minutes exposure to an air drying climate at +25C (humidity unspecified). This is followed by 210 minutes exposure to a salt fog climate at +25C. This is followed by 378 minutes exposure to a condensing water climate of 95 to 100%RH at +30C. This is followed by 180 minutes exposure to an air drying climate at +35C (humidity unspecified). This is followed by 120 minutes exposure to an air drying climate at +25C (humidity unspecified). The number of cycle repeats is to be sufficient for 1000 hours total test time, unless otherwise agreed.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

These tests are also referred to as a Cyclic Corrosion Tests, often abbreviated to CCT.

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.

ISO 9227

The European derivative of ASTM B117, the global standard for salt spray testing

Introduction

The salt spray test developed by the American Society of Testing and Materials (ASTM) test B117 is one of the most widely adopted standards. Its use is international and its provisions have been re-written into the national standards of other countries, ISO 9227 is the European derivative of this standard.

ISO9227 is an excellent reference document for the salt spray practitioner, with many helpful hints and tips contained in its useful appendixes. It is also regularly updated, so it is a standard that is continuously evolving. Practitioners applying the ISO 9227 test standard are responsible for checking they are using the most appropriate version for their application.

For a reference guide on how to test to this standard using an Ascott chamber click the button below;

Test Methodology PDF

Test Conditions

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of salt water solution (also referred to as fog or mist) which falls-out on to the specimens at a rate of 1.0 to 2.0 ml/80cm²/hour, in a chamber temperature of +35C. The chamber climate is maintained under constant steady state conditions. The test duration is variable.

NSS & AASS

ISO 9227 Standards - Ascott Analytical, the global leader in the design and manufacture of salt spray test chambers. UK - Worldwide

CASS

ISO 9227 Standards - Ascott Analytical, the global leader in the design and manufacture of salt spray test chambers. UK - Worldwide

Method

Salt spray testing is performed by placing samples in a test chamber designed in accordance with Paragraph 4 (Apparatus) of ISO 9227 and operated in accordance with Paragraph 8 (Operating conditions) of ISO 9227.

The test solution to be sprayed is prepared by dissolving pure sodium chloride into pure water, in a ratio of 5% sodium chloride to 95% water, by weight. The purity for each should be as specified in ASTM B117.

The salt solution should be prepared according to the nature of the test in accordance with Paragraph 3 of ISO 9227 and the 3 options are summarised below;

NSS (Neutral Salt Spray) – The pH of the salt solution fall-out should be maintained at a neutral pH (pH 6.5 to 7.2)

AASS – A sufficient amount of glacial acetic acid should be added to the salt solution (should modify the pH to 3.1 to 3.3)

CASS – A sufficient amount fo copper chloride dihydrate should be added to the salt solution to produce a concentration of 0.26g/l +/- 0.02g/l

At the time the samples are placed into the test chamber, it should be pre-conditioned to the operating temperature of 35˚C and producing fall-out at the specified rate. The salt fog fall-out rate is verified by using a minimum of two 80cm2 funnels per salt spray atomiser, each inserted into a measuring cylinder graduated in ml. These collectors are located inside the chamber, nominally at the same height as the test samples, one located close to the atomiser and one located away from the atomiser, in accordance with the positions specified in ASTM B117, but also taking into account the chamber manufacturers defined work-space.

Typical Application

The ISO 9227 test can be used to test the relative resistance to corrosion of coated and uncoated metallic specimens, when exposed to a salt spray climate at an elevated temperature.

The appearance of corrosion products (oxides – commonly referred to as white rust & red rust) is evaluated after a period of time. Test duration depends on the corrosion resistance of the coating; generally, the more corrosion resistant the coating is, the longer the period of testing before the appearance of oxides.

If you would like further information please call our experienced team on 01827 318040 or email sales@ascott-analytical.com

ISO 7253

Paints & varnishes – determination of resistance to neutral salt spray (fog)

Can be used to test the relative resistance to corrosion of paints and varnishes, when exposed to a salt spray (fog) climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.5ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

This test is also referred to as a Neutral Salt Spray or NSS test.

For further information on ISO standards visit; www.iso.org

Note; many ISO test standards have been harmonized with other European standards and these are now prefixed ‘EN’ (Euro Norm) or ‘** EN’ – where ** are the letters representing a European country/language code, for example ‘BS EN’ for a harmonized British standard in English language.

ISO 3770

Corrosion testing of metallic coatings – copper accelerated acetic acid salt spray test

Can be used to test the relative resistance to corrosion of metallic coatings, when exposed to a copper accelerated acetic acid salt spray climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of acidified (pH 3.1to 3.3) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +50C. This climate is maintained under constant steady state conditions. The test duration is variable.

Chamber volumes of less than 200 Litres are not permitted by this test standard.

This test is also referred to as a CASS test.

For further information on ISO standards visit; www.iso.org

Note; ISO 3770 has been replaced by ISO 9227.

ISO 3769

Corrosion testing of metallic coatings – acetic acid salt spray test

Can be used to test the relative resistance to corrosion of metallic coatings, when exposed to an acetic acid salt spray climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of acidified (pH 3.1to 3.3) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

Chamber volumes of less than 200 Litres are not permitted by this test standard.

This test is also referred to as an ASS test.

For further information on ISO standards visit; www.iso.org

Note; ISO 3769 has been replaced by ISO 9227.

ISO 3768

Corrosion testing of metallic coatings – neutral salt spray test

Can be used to test the relative resistance to corrosion of metallic coatings, when exposed to a salt spray climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

Chamber volumes of less than 200 Litres are not permitted by this test standard.

This test is also referred to as an NSS test.

For further information on ISO standards visit; www.iso.org

Note; ISO 3768 has been replaced by ISO 9227.

IEC 60068-2-52 – Methods 1-2

ISO 60068-2-52

Test specimens are placed in an enclosed chamber (a separate salt mist chamber and controlled humidity chamber are generally used) and exposed to a changing climate that starts with 2 hours exposure to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +15 to +35°C.  Depending upon method number, this is followed either by exposure to a high humidity climate of 40°, C93%RH; or air drying at 60 °C, under 30 % RH and then Wetting at 50°C.

The duration of high humidity and number of cycle repeats is variable depending on the test method.

Test method 1

One cycle consists of spraying samples with salt solution at 35 °C for 2h, followed by controlled humidity at 40 °C, 93% RH for six days and 22 h. The required number of cycles is four (28 days).

Test method 2

One cycle consists of spraying samples with salt solution at 35 °C for 2h, followed by controlled humidity at 40 °C, 93% RH for 22h. The required number of cycles is three (3 days).

IEC 60068-2-11

Environmental testing Part 2 Tests – Test Ka: salt mist

Can be used to test the relative resistance to corrosion of protective coatings, when exposed to a salt mist (spray) climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

This test is also referred to as a Neutral Salt Spray or NSS test.

For further information on IEC standards visit; www.iec.ch

IEC 68-2-11

Salt mist

Can be used to test the relative resistance to corrosion of protective coatings, when exposed to a salt mist (spray) climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.0ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

For further information on IEC standards visit; www.iec.ch

Note; IEC 68-2-11 has been replaced by IEC 60068-2-11.

EN ISO 7253

Paints & Varnishes – Determination of Resistance to neutral salt spray (fog)

Can be used to test the relative resistance to corrosion of paints and varnishes, when exposed to a salt spray (fog) climate at an elevated temperature.

Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of neutral (pH 6.5 to 7.2) salt water solution, which falls-out on to the specimens at a rate of 1.0 to 2.5ml/80cm²/hour, in a chamber temperature of +35C. This climate is maintained under constant steady state conditions. The test duration is variable.

Chamber volumes of less than 400 Litres are not permitted by this test standard.

This test is also referred to as a Neutral Salt Spray or NSS test.

For further information on European Standard (EN) visit; www.cencenelec.eu