Underwriters Laboratories (UL)
is a not-for-profit organization, which develops,
revises, and implement standards for safety. The
UL 1777 Standard tests chimney liners as a system
within a masonry chimney. UL 1777 was designed
to test the liner to the appropriate temperatures
as well as putting the liner through strength
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There are many parts to the UL 1777 tests. The
Temperature Tests determine whether the exterior
of the chimney will stay cool enough so that combustibles
touching the chimney (i.e.: floor joists, attic
rafters, etc.,) won't ignite. The temperature
test for solid fuels (coal and wood) simulates
a chimney fire.
Similar tests, but with lower temperatures are
done for oil, wood pellet and gas applications.
There is also a special test, UL 1738 for condensing
gas appliance flues. During this test the liner
is put through an accelerated corrosion test in
addition to the other tests.
Other tests that the liners must go through include
the Vertical Support Test, Loading Test, Strength
Test, Sweep Test, Abrasion Test, Torsion Test,
Flexibility Test and Rain Test. After passing
all of these tests, the manufacturer must then
work with UL for approval on their written installation
Then, they must enlist in UL's Follow Up Procedure.
This allows a UL representative to visit the factory
unannounced, usually once every three months,
to verify that the materials are in compliance
with their listing.
To have a truly UL Listed product, it must be
subjected to Underwriters Laboratories for testing
and later for their suprise visits to the manufacturing
facility, and of course, the product must bear
the UL trademark . Some companies test to UL Standards
by another testing laboratory. Their product can't
be UL Listed because UL didn't do the test. They
often advertise as "Listed to UL 1777".
Here at HomeSaver, we have maintained UL Listings
for almost two decades. We are proud to promote
the UL Listings that we have. Here are the following
UL listed HomeSaver chimney liners:
Thank you for your interest in HomeSaver Chimney
Liners and our UL listings.