To achieve pressure in the ultra-high vacuum range (<10-8 hPa), the following conditions must be met:

The bottom pressure of the vacuum pump should be less than 10 times the required ultimate pressure.
The materials used in the vacuum chamber and components must be optimized for minimum outgassing and have an appropriate surface finish rating.
Metal seals should be used (for example, CF flange connections or ISO flange standard Helicoflex seals).
Cleaning is essential for ultra-high vacuum, ie all parts must be thoroughly cleaned before installation and must be worn with grease-free gloves.
Equipment and high vacuum pumps must be baked.
Leaks must be avoided and eliminated before starting the heater. For this purpose, a helium leak detector or a quadrupole mass spectrometer must be used.
Baking significantly increases the desorption rate and diffusivity, and this causes the pumping time to be greatly reduced. As a final step in the manufacturing process, chambers for UHV applications can degrade at temperatures up to 900 °C. The subsequent baking temperature may reach 300 °C. The pump manufacturer's instructions for the maximum torrefaction temperature of the high vacuum pump flange are usually limited to a maximum temperature of 120 °C. If a heat source (eg radiant heating) is used in a vacuum device, the permissible radiant power must not be exceeded.

The equipment is put into operation after installation. After reaching a pressure of 10-5 hPa, turn on the heater. During the heating process, the vacuum gauge was operated at 10 hour intervals and degassed. If stainless steel vessels and metal seals with appropriate surface treatment grades are used, a baking temperature of 120 ° C and a heating time of approximately 48 hours are sufficient to achieve a pressure range of 10-10 hPa.

Baking should last until it reaches 100 times the expected ultimate pressure. Then turn off the heaters in the pump and vacuum chamber. After cooling, it is likely that the required ultimate pressure will be achieved. When the pressure is lower than 5 · 10-10 hPa and the internal surface area is large, it is advantageous to use a gas-incorporated pump (titanium sublimation pump) which extracts hydrogen gas escaping from the metal at a high volume flow rate.