2018 IPC
PLUMBING APPLIANCE. Water or drain-connected devices intended to perform a special function. These devices have their operation or control dependent on one or more energized components, such as motors, controls or heating elements. Such devices are manually adjusted or controlled by the owner or operator, or are operated automatically through one or more of the following actions: a time cycle, a temperature range, a pressure range, a measured volume or weight.
[M] WATER HEATER. Any heating appliance or equipment that heats potable water and supplies such water to the potable hot water distribution system.
501.4 Location.
Water heaters and storage tanks shall be located and connected so as to provide access for observation, maintenance, servicing and replacement.
502.5 Clearances for maintenance and replacement.
Appliances shall be provided with access for inspection, service, repair and replacement without disabling the function of a fire-resistance-rated assembly or removing permanent construction, other appliances or any other piping or ducts not connected to the appliance being inspected, serviced, repaired or replaced. A level working space not less than 30 inches in length and 30 inches in width (762 mm by 762 mm) shall be provided in front of the control side to service an appliance.
[M] ACCESS (TO). That which enables a fixture, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction (see “Ready access”).