The loyal challenge per nullity has character of appeal limited and not introduces a judgment appeal face per review in merit of the decision arbitration. allows only the assessment of the subsistence of the nullity strictly listed in art. 829 of the Italian Civil Code proc. civ., as cons Eguanza by errors in proceeding o in iudicando, with the consequence that only only in hypothesis of judgment termination, conclusions with the assessment of the nullity of the praise, it is possible the review of merit of the pronunciation arbitration that form object object of the possible.