A diver of Residual Group E at the time of the first diving end plans the second diving of 15 m after 1 hour 30 minutes Surface Interval Time. How long is Residual Nitrogen Time?

《The usage of Dive Table》

You can look for the contact of ① and ② as you have leaned before.
A number of the lower left corner is the Residual Nitrogen Time at 15m.

a) Residual Nitrogen Time

Correct answer： 13 minutes

You can understand that the quantity of residual nitrogen at the beginning of next diving is the same as the one that is accumulated in your body at 13 minutes at 15 m.

Residual Nitrogen Time is added to the second real Bottom Time.

*A Dive Table term*

■Residual nitrogen
The nitrogen that is left in the body after diving

■Residual Nitrogen Time
The time that is rearranged the quantity of the residual nitrogen.

■Residual Nitrogen Time Table
This Table displays the quantity of residual nitrogen from a previous dive.