In the mid-1990s, some manufacturers started to use coloured air intake tubes in order to speed up the manufacturing process and also to avoid assembly errors. However, this was done on an individual basis without any form of colour standardisation.
TRTA foresaw that an important potential advantage would not be realised: the simplification of troubleshooting in case of air leaks.
Together with various suppliers and manufacturers, TRTA developed a colour standard that became mandatory for all suppliers from 1998 onwards.. This coding has been the European standard ever since.
trta 19b