Losing Wudhu As a Result of Napping

Bismillah al-Rahman al-Rahim

As-salamu'alaykum wa rahmatullah,

How does one know that one has lost consciousness after one has taken a nap? How many minutes must have passed or what are the signs that would clearly indicate that one must make wudhu again? For example laying down with one's eyes closed - one may be completely alert. At what point would one reach the threshold of unconsciousness that would require making wudhu again?

In the Name of Allah, Most Merciful and Compassionate

wa `alaykum as salam wa rahmatullah wa barakatuh

(1) If is certain that one has seen a dream, then this is a sure sign that one has fallen asleep. One's ablution has therefore been invalidated.

(2) If one feels drowsy but can hear people around him speaking, then this is a sure sign that one has not fallen asleep, even if one does not understand what they are saying. One's ablution has therefore not been invalidated.

(3) If one does not experience anything to indicate with certainty whether or not one fell asleep, then one assumes that one did not fall asleep and one's ablution has therefore not been invalidated.

(cf. Bushra al-Karim Bi Sharh Masa'il al-Ta`lim, 1.30)

And Allah Most High knows best.

Hamza.