http://www.iihf.com/fileadmin/user_upload/PDF/Sport/IIHF_Official_Rule_Book_2014-18_Web_V4.pdf
RULE 177 – PENALTY-SHOT PROCEDURE/TAKING THE SHOT
x. The penalty shot is considered complete once:
4. The puck touches the boards anywhere between the centre red
line and icing line and does not go...