文档介绍：66 MOVABLE AND WALL- OR CEILING-HUNG ELECTRIC ROOM HEATERS - UL 1278 JUNE 21, 2000
b) If a radiant type heater is provided with a reflector, the reflector may have a focusing effect
that causes higher temperatures at a greater distance than the minimum distance between the
heater and the wall. In this case additional tests are to be conducted at increased distances.
The test time at each distance is to be sufficient to observe the ultimate results. See .
With respect to , to observe the ultimate results, the test is to be continued for 7 hours.
However, the test may be discontinued after 2 hours if this duration of testing produces no discoloration
of the terry cloth material.
The heater is to be supported on a horizontal surface that abuts the vertical wall. The side of the
heater that radiates or convects heat is to face the wall. The wall is to consist of 3/4-inch (-mm) thick
fir plywood, and is to be covered with one layer of terry cloth material. The wall is to be constructed so the
grain of the plywood runs in the horizontal direction. The wall is to extend at least 12 inches (305 mm)
beyond the heater on both sides and 12 inches above the heater. Any heater projections such as guards
or grilles in the front of the heater that do not require tools for their removal (see ) are to be
removed.
For a heater that includes a stand or feet that project beyond other heater surfaces in front of the
heater, the wall is to include a recessed ″toe space″ next to the floor. The ″toe space″ shall be 3-1/4
inches ( mm) deep, 4-1/4 inches ( mm) high which, with respect to the heater feet or stand,
determines the closest distance the heater can be placed to the wall. The terry cloth material is to be
applied to the vertical wall such that it extends to the floor, draping over the ″toe space″ opening. When
the heater is inserted, the terry cloth will contour the stand or feet of the heater.
Exception: For a