Contract law is how to stipulate the equipment warranty period

First, whether there is a specific agreement between the parties on the quality; second, no agreement or agreement is unclear, the agreement to supplement. Can not reach a supplementary agreement, in accordance with the relevant provisions of the contract or trading habits. Still can not be determined, in accordance with national or industry standards to fulfill. Specifically depends on what equipment, safety equipment (boilers, etc.) shelf life to be longer. Specific questions are recommended to consult by phone.