you can use it this way so you can turn it on in channels you want it to run in

on @*:TEXT:*:#:{
  if ($nick(#,$nick,r) && $istok(%sflood,$chan,44))  {
    inc -u5 $+(%,flood.,$nick)
    if ($($+(%,flood.,$nick),2) = 8) {
      mode $chan +b ~q: $+ $address($nick,2)
      msg $chan $nick You have been silenced for two minutes. Please don't flood.
      msg #staff $nick has been silenced in $chan for flooding.
      $+(.,timersilenced,.,$nick) 1 120 mode $chan -b ~q: $+ $address($nick,2)
    }
  }
}
menu channel {
  .Silence on Flood
  .. $iif($istok(%sflood,$chan,44),Turn Off in Room # ,Turn On in Room # ):{ set %sflood $iif(!$istok(%sflood,$chan,44),$addtok(%sflood,$chan,44),$remtok(%sflood,$chan,1,44)) | echo -a $iif($istok(%sflood,$chan,44),Silence on Flood is now On in room # .,Silence on Flood is now Off in room # .) } 
}

Doodle said:

whats the proper 'if' if they're voiced?
um you can do it like this

 if ($nick isvoice #) or you can do it like this if ($nick(#,$nick,v) or you can add both voiced and reg users to it like this
if ($nick(#,$nick,vr)