Proceedings for the challenge for nullity of the arbitral award pursuant to art. 829 cod. proc. civ. do not permit the court of appeal to review the correctness and adequacy of the reconstruction of the facts and the assessment of the evidence carried out by the arbitrators, the limits of the cognisance of the court hearing the challenge being analogous to those applicable in proceedings before the Court of Cassation; it follows that the principle of non-contestation cannot operate on the basis of the defences raised in the proceedings for the challenge of the arbitral award.