Higher altitudes reduce this efficiency. The lowest temperature that kills a microbial suspension in 10 min. The time required to kill a suspension under given conditions. Since there is no such thing as absolute death, we not use this measurement. This is often done in an autoclave.
Extra time is a margin of safety.
The pressure step. The run time. The exhaust step. Membrane filters- Nitrocellulose, polycarbonate, etc. Lysol is common example.