The max reaction force Fmax at the length of the sound wave L0 during a opening of is given in the safety valve specification. The reaction forces F at every turn round is calculated according to the formula below: Fn = Fmax*(0,2+Ln/L0) ≤ Fmax Fn = reaction force at every turn round of the media. Fmax = stationary reaction forces (at the outlet into the ATM, value according to the safety specification) L0 = length of the sound wave Ln = length of the straight pipe after a turn round For different installation cases we find the reaction force distribution on every bend, but i could not found the bases of this calculation, plz. explain it