Process advantages of vacuum are compared with conventional inert-gas atmospheres with respect to purity, repeatability, and operating cost. Recognition of vapor pressures of workloads, containers, and furnace hot-zone parts is essential to predicting system performance parameters, maintenance schedules, and pumping equipment selection. Cooling requirements of batch equipment are evaluated with respect to quench characteristics, equipment turn-around time, and workpiece surface quality. Design features of system details are evaluated for such factors as heat removal (jacketing vs traced cooling), safety (one-piece electrode design), integrity at full vacuum, and partial pressure operation. Typical systems are examined for conformity to design criteria established.