An emulsion manufactured from the PG 67-22 represented in Figure 1 could be manufactured under normal atmospheric conditions, while an emulsion manufactured from the 4% SBS asphalt must be manufactured under pressure. As a general rule, if the MEET is greater than 95ºC (203ºF) the emulsion will have to be produced under pressure. The amount of pressure required can be obtained by consulting steam data temperature tables (8) using the absolute pressure value plus 20%. It should be noted that this pressure is absolute pressure and not gauge pressure; gauge pressure would be equivalent to absolute pressure less 1 bar (14.5 psi). For demonstration purposes, consider the SBS-modified asphalt presented in Figure 1. The manufacturing pressure of the SBS-modified asphalt emulsion based on the MEET of 118ºC (245ºF) can be obtained from Figure 2.