▁case ▁of ▁real - time ▁monitoring ▁by ▁d ive ▁computer , ▁descent ▁rate ▁is ▁not ▁specified , ▁as ▁the ▁consequences ▁are ▁automatically ▁account ed ▁for ▁by ▁the ▁program med ▁algorithm . ▁ ▁B ottom ▁time ▁ ▁B ottom ▁time ▁is ▁the ▁time ▁spent ▁at ▁depth ▁before ▁starting ▁the ▁as cent . ▁B ottom ▁time ▁used ▁for ▁decom pression ▁planning ▁may ▁be ▁defined ▁differently ▁depending ▁on ▁the ▁tables ▁or ▁algorithm ▁used . ▁It ▁may ▁include ▁descent ▁time , ▁but ▁not ▁in ▁all ▁cases . ▁It ▁is ▁important ▁to ▁check ▁how ▁bottom ▁time ▁is ▁defined ▁for ▁the ▁tables ▁before ▁they ▁are ▁used . ▁For ▁example , ▁tables ▁using ▁Bü hl mann ' s ▁algorithm ▁define ▁bottom ▁time ▁as ▁the ▁el apsed ▁time ▁between ▁leaving ▁the ▁surface ▁and ▁the ▁start ▁of ▁the ▁final ▁as cent ▁at ▁ 1 0 ▁metres ▁per ▁minute , ▁and ▁if ▁the ▁as cent ▁rate ▁is ▁slower , ▁then ▁the ▁excess ▁of ▁the ▁as cent ▁time ▁to ▁the ▁first ▁required ▁decom pression ▁stop ▁needs ▁to ▁be ▁considered ▁part ▁of ▁the ▁bottom ▁time ▁for ▁the ▁tables ▁to ▁remain ▁safe . ▁ ▁As cent ▁rate ▁ ▁The ▁as cent ▁is ▁an ▁important ▁part ▁of ▁the ▁process ▁of ▁decom pression , ▁as ▁this ▁is ▁the ▁time ▁when ▁reduction ▁of ▁ambient ▁pressure ▁occurs , ▁and ▁it ▁is ▁of ▁critical ▁importance ▁to ▁safe ▁decom pression ▁that ▁the ▁as cent ▁rate ▁is ▁compatible ▁with ▁safe ▁elim ination ▁of ▁in ert ▁gas ▁from ▁the ▁diver ' s ▁t issues . ▁As cent ▁rate ▁must ▁be ▁limited ▁to ▁prevent ▁su