What is the degree of vacuum considered as vacuum
Wiki /
07/25/2025
In engineering and technical contexts, a space is considered under vacuum as soon as its absolute pressure is below standard atmospheric pressure (101 325 Pa or 1 atm).
For practical purposes, vacuum is further classified by pressure ranges:
Rough (low) vacuum: ~10⁵ → 10² Pa (760 → 1 Torr)
Medium vacuum: ~10² → 10⁻¹ Pa (1 → 10⁻³ Torr)
High vacuum (HV): ~10⁻¹ → 10⁻⁵ Pa (10⁻³ → 10⁻⁷ Torr)
Ultra-high vacuum (UHV): < 10⁻⁵ Pa (< 10⁻⁷ Torr)
Extreme-high vacuum (XHV): < 10⁻⁸ Pa (< 10⁻¹⁰ Torr)
Thus, any pressure below 1 atm qualifies as vacuum, but the required level depends on the application—from household vacuum cleaners (rough vacuum) to particle accelerators (UHV/XHV).
