I am interested to know what is the acceptable range for deviation of minimum and maximum temperature in Dry heat sterilizer during sterile hold priod and which standard specify this under which clause may be American or European standard or ISO

Dear,

ANSI/AAMI standard ST40 "Table top dry heat sterilization and sterility assurance in dental and medical facilities" does not mention deviation allowed in tempeature exposure period. Annex A of the standard explain that once the chamber is loaded, chamber temperature depresses due to effect of cold load, therefore exposure time commences when the pre-established chamber temperature is achieved.

I hope it helps,
Yaffa Raz

Dear Suresh Patel

Dry heat is not recommended for use in hospital environment, as it is difficult to control the process. According to Pharmakopoe, WHO the UK HTM 2020 Part 3, NHS Estates, the following time/temperature are recommended:

• 160°C for 120 minutes
• 170°C for 60 minutes
• 180°C for 30 minutes

The exposure times will vary depending on the types of devices being sterilized.
It is also important to understand that the total cycle time - including heating the chambre to the correct temperature, sterilization, and cooling - is usually twice as long as the time noted here.

Kind regards
Josy Holdener