Short answer
Impulse resistance refers to performance under repeated pressure cycles. Passing a single hydrostatic test does not mean the same impulse life has been verified. A cycle count should only be compared together with the test temperature, pressure profile, bending and sample conditions.
Source: S078
Technical explanation
In hydraulic hoses, steady pressure and repeated pressure rises are different loading conditions. The method used in the impulse test and the product class are important for interpreting the result. ISO 6803 covers the hydraulic pressure impulse test without flexing; it should not be assumed that a test represents all real machine movements. Additional information is needed to convert a laboratory cycle count directly into a field life in years or operating hours.
Source: S078
Topic-specific checkpoints
| Item | Description |
|---|---|
| Test method | The standard, edition and test type used. |
| Test condition | Pressure profile, temperature, bending and sample size. |
| Result | Cycle count and acceptance criterion; not a warranty life. |
| Field equivalent | Assessment with actual load cycle and movement information. |
Source: S078
How is it assessed in practice?
When comparing the impulse claims of two products, do not simply pick the largest cycle count. Request the test method, sample size, temperature and the applied pressure waveform in the same table. If load data for the actual system is not available, record this as 'measurement required'. For example, a line that operates rarely during the year but experiences frequent pressure shocks and a line that operates steadily for long periods should not be placed in the same risk group based on hours alone.
Original editorial recommendation; not a clause of a standard.
Frequently asked questions
How many years is one million cycles?
Even if the field cycle frequency is known, equivalence between laboratory load and actual load is not automatic. Do not convert a cycle claim on its own into a calendar life.
Source: S078
Source coverage
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S078
ISO 6803:2017 ISO · accessed 2026-10-19 Abstract: hydraulic-pressure impulse test without flexing; public metadata only