ISO 16232:2018 - Road vehicles - Cleanliness of components and systems

New ISO 16232:2018 - International counterpart to VDA 19.1

ISO 16232:2018 "Road vehicles - Cleanliness of components and systems" is the latest version and thus now the international equivalent of VDA19.1. Both guidelines were developed in cooperation with numerous companies within and around the automotive industry. The currently valid edition of ISO 16232:2018 replaced the 10-part previous version ISO 16232-1 to ISO 16232-10:2007 in 2018. By merging them into a single document, redundant information was reduced. CleanControlling carries out tests for you according to the current ISO 16323:2018.

A main focus in the creation of ISO 16232:2018 was to achieve an alignment with the standard recommendation of VDA 19.1, so that a largely uniform procedure for testing technical cleanliness exists in the national and international area. Extensions and adaptations have been made which are generally based on VDA 19.1. Particularly noteworthy here is the inclusion of new chapters which describe the general procedure and extraction of the cleanliness test in detail. Additional graphics have been added for easy comprehension. In comparison to VDA 19.1, extensions have been incorporated taking into account international and national documents from the field of measurement technology and particle analysis.

Extraction methods

New extraction methods

In the updated ISO standard, the procedures of release and air extraction (blowing off, flow through) have been newly included, which are to be carried out analogous to VDA 19.1. In addition, contrary to VDA 19.1, ISO 16232:2018 offers a third possibility of low flow directly to the analysis filter.   

Spray extraction

Contrary to VDA 19.1, ISO16232:2018 explicitly prohibits the use of laboratory syringe bottles for extraction during syringe extraction; rinsing is not affected.

Ultrasonic extraction

In order to check the performance characteristics of the ultrasonic bath, the new ISO 16232 as well as VDA 19.1 include the examination by means of perforation on an aluminium foil. In the ISO standard, the risk of additional contamination caused by the aluminium foil is explained and for this reason the alternative method using indicator liquid is described.

Declining test

The decay measurement is now mandatory and must be carried out identically to VDA 19.1 with all 6 decay steps. In the old version the decay measurement could be stopped after at least 3 extraction steps if the decay criterion was reached. 

To simplify the determination and presentation of the decay behaviour, all particle size classes contained in the cleanliness specification can be summed up. In the new version, it is sufficient if there is a decreasing trend in each size class. On the other hand, in the current VDA 19.1, a declining trend in each particle size class must be ensured.

In the decay measurement according to the new ISO standard, only particles are taken into account, but it is also possible to include fibers in the decay measurement if fiber requirements exist. The consideration of fibers in the decay measurement is not included in VDA 19.1. 

Blank value calculation

The blank value must be determined according to ISO 16232-2018 for all cleanliness characteristics that must be fulfilled according to the specification. In the case of requirements limited to the largest permissible particle, ISO 16232-2018 and VDA 19.1 do not allow particles in the size class of half the limit value according to ISO 16232-2018 and VDA 19.1, whereas in the old version a more stringent calculation was specified in which no particle was permissible in the next smaller size class of half the limit value.

If no requirements are known for the component to be tested, the new ISO 16232:2018, identical to VDA 19.1, states that no particles larger than 50 µm may be contained in the blank value. In the old version of ISO 16232, no particles larger than 50 µm were permissible either. In addition, less than 4000 particles >5 µm and less than 500 particles >15 µm were permitted per 100 ml extraction fluid.

The 10 parts of the previous version ISO 16232-1:2007 to ISO 16232-10:2007

Part 1 Vocabulary
Part 2 Method of extraction of contaminants by agitation
Part 3 Method of extraction of contaminants by pressure rinsing
Part 4 Method of extraction of contaminants by ultrasonic techniques
Part 5 Method of extraction of contaminants on functional test bench
Part 6 Gravimetric analysis
Part 7 Particle sizing and counting by microscopic analysis
Part 8 Particle nature determination by microscopic analysis
Part 9 Particle sizing and counting by automatic light extinction particle counter
Part 10 Expression of results