Common use of Atmospheric factor fa Clause in Contracts

Atmospheric factor fa. This factor indicates the effects of environmental conditions (pressure, temperature and humidity) on the air drawn in by the engine. The atmospheric factor formula differs according to the type of engine. 5.4.2.1.1. Naturally aspirated and mechanically pressure charged engines  99   T 0.7 fa =  p  * 298   s    5.4.2.1.2. Turbocharged engines with or without charge air cooling  99 0.7  T 1.5 fa =  p  * 298   s    1 The tests may be carried out in air-conditioned test rooms where the atmospheric conditions may be controlled. In the case of engines fitted with automatic air temperature control, if the device is such that at full load at 25 °C no heated air is added, the test shall be carried out with the device fully closed. If the device is still operating at 25 °C then the test is made with the device operating normally and the exponent of the temperature term in the correction factor shall be taken as zero (no temperature correction).