If the engine of the equipment or its hydraulic system is fitted with (a) fans(s) it (they) must operate during the test. The fan speed is, in accordance with one of the following conditions, stated and set by the manufacturer of the equipment and must appear in the test report, this speed being used in further measurements.

1. (a)

   Fan drive directly connected to the engine

   If the fan drive is directly connected to the engine and/or hydraulic equipment (e.g. by belt drive) it must operate during the test.

2. (b)

   Fan drive with several distinct speeds

   If the fan can work at several distinct speeds the test shall be carried out either

   • at its maximum working speed, or

   • in a first test with the fan set at zero speed and in a second test the fan set at maximum speed. The resulting sound pressure level L_pA shall then be calculated by combining both test results using the following equation:

     $L_{\mathrm{pA}}=\mathrm{10\; lg}\left\{\mathrm{0,3}\times {10}^{\mathrm{0,1\; LpA\; ,0 \%}+\mathrm{0,7}}\times {10}^{\mathrm{0,1\; LpA\; ,100 \%}}\right\}$

     where:

     L^pA,0 % is the sound pressure level determined with the fan set at zero speed

     L^pA,100 % is the sound pressure level determined with the fan set at maximum speed.

3. (c)

   Fan drive with continuous variable speed

   If the fan can work at continuous variable speed, the test shall be carried out either according to 2.1(b) or with the fan speed set by the manufacturer at no less than 70 % of the maximum speed.