Short answer
Swelling, layer separation and cracking are different signs of damage. Chemical attack, temperature, aging or mechanical stress must be investigated; a single cause or a safe remaining life cannot be determined from external appearance alone.
Technical explanation
A hose can be a multi-layer construction; the inner tube, reinforcement and outer cover serve different functions. Fluid incompatibility or unsuitable conditions can affect these layers in different ways. A chemical resistance chart is only an initial assessment; the mixture, temperature, concentration and duration of use are important. A suspicion of delamination is not considered resolved by cleaning the surface and may require expert examination of the product's internal structure.
Topic-specific checkpoints
| Item | Description |
|---|---|
| Swelling | Location, dimensional change and exposure |
| Layer separation | Need for internal structure examination |
| Cracking | Propagation, direction and environmental conditions |
| Process | Fluid, cleaning and temperature history |
How to evaluate it in practice
Record whether the sign is inside or outside and whether it is local or widespread. In addition to the process fluid, investigate cleaning agents and recent recipe changes. Preserve the damaged sample for examination; random cutting can alter the evidence. If similar assemblies operate under the same conditions, carry out a pattern analysis. If the definitive cause has not been determined, keep this open in the report; do not transfer a suspicion to the product record as if it were a verified result. Do not return the hose to service based on its external appearance until the cause and extent of the internal damage have been determined by a competent examination.
Original editorial recommendation; not a clause of a standard.
Frequently asked questions
Why can a hose that looks suitable in a chemical chart swell?
The actual mixture, temperature, contact time or cleaning conditions may differ from the conditions on which the chart is based.
Source coverage
-
S020
Chemical Resistance Chart Gates · accessed 2026-10-19 PDF page 2 / printed page 1: Chemical Resistance Table, notes
-
S036
Industrial Hose Safety Connections Gates · accessed 2026-10-19 PDF pp. 6–8 construction and selection; pp. 10–19 maintenance; pp. 21–27 special services