Reverberator - specifying decay time in seconds

Hi all,

I'm currently trying to implement the reverberator function to some audio.

However, the issue i am having is that the reverb time applied to the audio needs to be equal to the average reverb time I've previously calculated for the room.

The reverberator only defines the decay factor as an arbitrary value between 0 and 1, so what im wondering is how to convert my reverb time in seconds into an equivalent value between 0 and 1.

Any help would be greatly appreciated!