The expression „water tightness“ leaves room for interpretation
The expression “watertight“ has established itself as a description for the features of parts and designs in our colloquial language. Very often, expressions like “watertight” are used in construction plans as specifications of the leakage rate. But when taking a closer look, it becomes obvious that this expression leaves a great scope for interpretation. It is not specified how this demand set on the degree of tightness is to be understood: Is the accumulation of a drop or liquid film on the surface of the component being tested still acceptable when it is described as “watertight”? Or is any escape of water to be excluded at all? These counter-questions clearly show that the colloquial term “watertight“ is not suitable for defining tightness specification. Therefore, information on the water tightness of parts and components must be differentiated more intently.
Distinction of six classes
According to “ISO/TR 11340:1994-07, Rubber and rubber products - Hydraulic hose assemblies – External leakage classification for hydraulic systems”, the leakage of fluids can be classified into six different classes. This allows for making an evaluation but does not provide any quantification.
Fig.1: Leakage classification according to ISO/TR 11340: 1994 (E)