The challenge for nullity of an arbitral award constitutes proceedings subject to restricted grounds of appeal, which may be brought exclusively within the limits established by Article 829 of the Code of Civil Procedure, in which the rule of specificity in the formulation of grounds applies, given the rescissory nature of the remedy and the need to enable the court and the opposing party to verify the correspondence of the challenges raised with the grounds exhaustively provided for by the statute.
The defect of failure to rule pursuant to Article 829, paragraph 1, No. 12 of the Code of Civil Procedure cannot be found where the arbitral tribunal has expressly ruled on the objections raised by the party, even if declaring them inadmissible on grounds of tardiness or irrelevance to the thema decidendum as delimited by the request for arbitration.
The contradiction in the award relevant for the purposes of nullity under Article 829, paragraph 1, No. 11 of the Code of Civil Procedure must emerge between the different components of the operative part, or between the reasoning and the operative part, whereas internal contradiction between different parts of the reasoning is not relevant as an autonomous defect, unless it absolutely prevents the reconstruction of the logical and legal reasoning underlying the decision due to the total absence of reasoning corresponding to its functional model.
Proceedings to challenge an arbitral award concern solely the verification of the legality of the decision rendered by the arbitrators and not the re-examination of the questions of merit submitted to them, so that the findings of fact made by the arbitrators and the evaluation of the evidence acquired during the proceedings are not subject to review, unless the reasoning on the point is completely absent or absolutely deficient.
In relation to arbitral proceedings, the violation of the principle of the right to be heard must be assessed from a dynamic-functional perspective, aimed exclusively at ascertaining whether an actual impairment of the possibility to plead and contradict has been caused; the nullity of the award may be declared only where, following the allegation of a defect capable of causing it, there is an indication of the specific prejudice that it has caused to the party's right of defence.
The principle of the right to be heard in arbitral proceedings, whilst being mandatory pursuant to Article 101 of the Code of Civil Procedure, must be appropriately adapted to the nature of the proceedings, in the sense that the parties must be afforded the opportunity to present their respective contentions, to examine the evidence and the results of the proceedings, to submit written submissions and replies, and to have timely knowledge of the opposing party's applications, without formal or procedural defects being capable of invalidating the award where they have not actually frustrated the legitimate defensive claims of the parties.