automatic de-icing
Mechanical systems which melt or remove ice and snow from a structure's surface.
Automatic de-icing systems are mechanical devices or webs of hot tubes or wiring which melt or scrape snow and ice off of the surfaces of a structure. These do not include normal design features such as sloped roofs or window coverings.
The equipment acts on snow or ice at the structure, either through a mechanical device or through heat supplied by tubes or wiring. The definition includes both melting and physical removal, rather than requiring every system to work by heat.
A snow retention system holds snow on a roof to control its fall. De-icing equipment removes or melts it. A sloped roof or other passive surface shape can shed snow without being a de-icing device.