Your logged in session stays active as long as you are moving between pages or refreshing a page on the website.
When a page loads, a timer automatically starts counting.

At 30m, for supervisors/managers/administrators, you will be logged off IF you’re on a registered device setup in access restrictions (IP or cookie)

Every other condition logs you out at 15m.

This is done to ensure your security in case you walk away from the site, your session is not left open, and anyone could access your security level. Given the confidential information in the site, this cannot be removed.