The bailee is liable for the loss of the thing, even if it should be through a fortuitous event:
(1) If he devotes the thing to any purpose different from that for which it has been loaned;
(2) If he keeps it longer than the period stipulated, or after the accomplishment of the use for which the commodatum has been constituted;
(3) If the thing loaned has been delivered with appraisal of its value, unless there is a stipulation exempting the bailee from responsibility in case of a fortuitous event;
(4) If he lends or leases the thing to a third person, who is not a member of his household;
(5) If, being able to save either the thing borrowed or his own thing, he chose to save the latter. (1744a and 1745)