These "Corporate Job Descriptions" are the binding and enforceable. When we are concerned about being assigned "out of title" work, these are the duties and tasks that we must be following.
Many of the titles we represent have 'levels' (i.e. Respiratory Therapist Level 1 and Level 2), each with a unique role under these job descriptions. This is important, because higher-level work deserves higher-level pay. Get to know your job description, as well as any levels above yours, to be sure the City is compensating you properly for the work you are performing.