The challenge for annulment of an arbitral award constitutes a remedy of limited scope, in the sense that an award may be challenged exclusively on the grounds expressly provided for in Article 829 of the Code of Civil Procedure, and any grounds of challenge must necessarily find correspondence within those provisions.
The sanction of nullity of an award for contradictory provisions, as provided for in Article 829, subsection 1, No. 4, of the Code of Civil Procedure, must be understood to mean that the contradiction must emerge either between the various components of the operative part of the award, or between the reasoning and the operative part thereof. By contrast, contradiction between different sections of the reasoning may assume relevance only when it determines the absolute impossibility of reconstructing the logical and legal process underlying the decision due to the complete absence of reasoning that conforms to its functional model.
The ground for annulment of an award on account of failure to observe the rules of law, as provided for in Article 829, subsection 2, of the Code of Civil Procedure, exists in the presence of violation and misapplication of legal norms and is not available for matters pertaining to the arbitrators' evaluation of the probative evidence, inasmuch as such evaluation has been contractually entrusted to the institutional competence of the arbitrators themselves.
The failure by arbitrators to admit certain means of proof on the grounds of alleged unsuitability or superfluousness cannot be contested by way of an application for annulment of the arbitral award, as such evaluation has been contractually entrusted to the institutional competence of the arbitrators.
The circumstance that an arbitrator does not consider it necessary to order a technical expert appraisal does not constitute a violation of the right to be heard and the right to a fair hearing; rather, it is the result of a reasoned evaluation of the documentary evidence, provided that the parties have been afforded the opportunity to present their respective arguments and to reply to those of their opponent.