Fh Value Calculation in Dry Heat Sterilization

When it comes to moisture-sensitive items, steam sterilization is not appropriate and may damage the accessories contacting drug products. Fh value is used in dry heat sterilization as a heat penetration factor.


Fh Value = Heat Penetration Factor

Δt = Sterilization Hold Time in Minutes

T = Average Temperature of all probes during a sterile hold in °C

z = Temperature Coefficient in °C

For steam sterilization, the term right to “T” was 121.1°C whereas, in dry heat sterilization, it is 170°C.

Difference between F0 and Fh Value

The assumed z-value for F0 is 10°C for sterilization range of 100 to 130°C

The assumed z-value for Fh is 20°C for sterilization range of 160 to 200°C

Theoretical Requirement for F0 is 121.1°C at 30 min. of sterile hold time

Theoretical Requirement Fh is 170°C at 32 min. of sterile hold time

Related: F0 Value Calculation in Steam Sterilization

Post a Comment

Previous Post Next Post