Installation Manual

Snowfall
Snowfall patterns vary widely with location. A system design that works well in
one city may be inadequate in another. The energy required to melt snow
varies with air temperature, wind speed, relative humidity, snow density, and
the depth of the snow on the pavement.
The effective power of a snow-melting system (that is, the power delivered to
the top surface on the pavement) is used to warm the fallen snow to melting
temperature, to supply the heat to melt the snow, to make up for evaporation
losses from the surface, and to make up for both convection- and radiation-heat
losses from the pavement surface.
The power required in a given situation is strongly influenced by whether the
surface is kept clear as snow falls. If snow is melted immediately as it falls, the
system must make up for convection-, radiation-, and evaporation-heat losses
as well as melt the fallen snow. However, if a light film of snow is allowed to
cover the surface, the insulating blanket of snow reduces or eliminates the loss-
es due to convection, radiation, and evaporation, and more of the effective sys-
tem power is available for melting snow.
15
ElectroMelt System
Design Guide
Supplemental Design
Information
Factors Affecting
Snow Melting System Design
All surface points above 32°F.
Heat loss varies with snow cover.
Snow-melting systems are installed for convenience and safety. They are often
thought of only in terms of snowfall, but an important-and often the principal-
function may be anti-icing.
Anti-icing is the ability of the system to prevent the formation of ice on the pave-
ment surface; it is the ability to maintain all points on the surface above 32°F for
given temperature and wind conditions. The anti-icing behavior of a system
must be considered when the primary objective of the system is to reduce slip-
ping hazards or when tracking or runoff of water from adjacent unheated pave-
ment areas is a potential problem.