Calculations must account for any liquid that will flash to vapor either as a result of the pressure reduction or because of the combined effects of pressure reduction and vaporization if the fluid is intimately contacted by hotter material on the low pressure side. The impact of flashing as a result of pressure reduction is calculated using the two-phase flow methodology discussed later in this section. If flashing may result from the mixing of the two fluids, the high pressure side fluid flow through the tube is calculated using the steady state flow methodology and this flow should then be assumed to reach the low pressure side temperature to generate the incipient relief rate at the initial tube break.