This part of ISO 20783 specifies three test methods to assess the stability of emulsions within the category HFB, as defined in ISO 6743-4[5].Method A describes a method for the determination of stability during storage at ambient temperature [(20 ± 2) ℃] and is applicable to HFB and HFB.LT fluids.Method B describes a method for the determination of stability during storage at medium temperature [(70 ±2) ℃] and is again applicable to HFB and HFB.LT fluids.Method C describes a method for the determination of stability during storage at low temperature [(-10 ±2) ℃] and is applicable only to HFB.LT fluids.note: 1) LT is the designation for low temperature applications.