The pressures in baked an unbaked experimental beam-pipes are calculated as a function of time. These results exclude gas impact desorption effects stemming from, for example, species created by the colliding beams. Three general cases have been calculated: Case {number_sign}1: an unbaked system cryopumped by the 4.2{degree}K apertures of the DO magnets; Case {number_sign}4: an unbaked system pumped by the 4.2{degree}K apertures of the DO magnets, and with a 10,000 L/sec LHe cryopump located proximate to the DX magnets in the DX to D0 beam pipes; Case {number_sign}6: baked beam pipes pumped by the 4.2{degree}K apertures of the D0 magnets and sputter-ion pumps (i.e., SIPs), with non-evaporable getters (i.e., NEGs), bracketing the experimental beam-pipes. The infinite combinations of non-simultaneous system pumpdowns have been excluded as they are impossible to enforce or predict in the heat of operation.