Турки писали.
Фразы контекста (переводить не нужно):

1. The (system) must always be operable with sufficient vacuum pressure, also at the end of the travel time for operation with the worst (conditions).
2. Temperature differences in the duct cross section may not exceed 10 K. The temperature difference may be a maximum 30 K at the end of the travel time. - здесь может пониматься как «по окончании изменения режима», но вряд ли, эта глава, как и все остальные, не о режимах.

Ближе к справедливому значение во фразах ниже:
3.- The (system) must be designed for the fuels specified in data sheets without restrictions in terms of performance, travel time, operation or emissions.
4. The (system) must be dimensioned so that at the end of their travel time the required performances and load change speeds can be operated even when the end of the travel time of the whole system is reached.
5. These values must be specified in the corresponding data sheet.
The “travel time” property is especially not satisfied when
• the equipment has to be used more than twice a day
• the temperature has increased by more than 20 K in relation to the design data and exceeds the value specified in the data sheet,
• the temperature difference before (system) is more than30 K,
• the gas side resistance has risen by more than 20% in relation to the guaranteed value,
• the permissible material temperature of the (system) (even at the guaranteed load change speeds) is exceeded.
A flushing of the (system) is not permissible during the travel time.

Однако здесь же:
• End of the running time of the wearable parts.

Спасибо за любые догадки.