Japanese–English glossary
Dirty hold time (DHT)
ダーティホールドdātī hōrudo
The maximum time equipment may stand soiled after use before cleaning starts, while the validated cleaning procedure remains effective. Residues dry or degrade and microorganisms grow with time, so cleaning validation studies include the longest expected dirty hold. Cleaning logs record the end of use and the start of cleaning so that compliance with the limit can be shown, and exceeding it is normally handled as a deviation. Japanese documents also use the full loanword with 'time' added.