Section 1313 - Collective bargaining agreements(a) Collective bargaining shall commence at least 90 days prior to the expiration date of any current collective bargaining agreement or in the case of a newly certified exclusive representative within a reasonable time after certification.(b) Negotiating sessions including strategy meetings of public employers, mediation and the deliberative process of binding interest arbitrators shall be exempt from Chapter 100 of Title 29. Hearings conducted by binding interest arbitrators shall be open to the public.(c) The public employer and the exclusive bargaining representative shall negotiate written grievance procedures by means of which bargaining unit employees, through their collective bargaining representatives, may appeal the interpretation or application of any term or terms of an existing collective bargaining agreement; such grievance procedures shall be included in any agreement entered into between the public employer and the exclusive bargaining representative.(d) Any contract or agreement reached between a public employer and any exclusive representative organization shall be for a minimum period of 2 years from the effective date of such contract or agreement unless otherwise mutually agreed upon by the public employer and the exclusive representative. (e) No collective bargaining agreement shall be valid or enforceable if its implementation would be inconsistent with any statutory limitation on the public employer's funds, spending or budget, or would otherwise be contrary to law.(f) Public employers shall file with the Board a copy of any agreements that have been negotiated with public employee representatives following the consummation of negotiations. The Board shall maintain a current file of all such agreements.69 Del. Laws, c. 466, §1; 72 Del. Laws, c. 272, §§ 2, 7; 74 Del. Laws, c. 173, § 2.;