Rule 304: If a person departs from the limits of tawaf and enters the Holy Ka'ba, the tawaf is invalidated and it must be repeated. It is preferable (al awla) that tawaf be first completed and then performed again, if the departure took place after completing half of tawaf.
Rule 303: If a pilgrim departs from tawaf to the `Shadharwaan', tawaf becomes invalid commensurate to the extent of the departure. After making good the distance, he should, as a matter of precaution, complete the tawaf and then repeat it.
In the course of tawaf, one should, as a matter of precaution, not extend one's arm towards the Shadharwaan or the wall of the Holy Ka'ba to touch a corner or whatsoever.
Rule 306: If, in the course of tawaf, a pilgrim enters Hijr Ismail, due to an oversight or out of ignorance, the round in which this occurs is invalid; there is no option but to repeat it, better though, after completing the entire tawaf.
The same rule applies, as a matter of precaution, to walking on the wall of the Hijr. While sticking to the course of tawaf, the pilgrim must not touch the wall of the Hijr either.