CEMLINE® STONESTEEL® lining is a hydraulic cement uniformly applied
to the interior of the tank. The CEMLINE STONESTEEL lining has been
manufactured by CEMLINE since 1935. This is a proven method of corrosion
prevention for hot water tanks and heaters. This lining application
is the result of considerable research by CEMLINE CORPORATION® and
a patented product until the patent expired. CEMLINE STONESTEEL
lining is a formulation of hydraulic cement designed with the
same thermal coefficient of expansion and contraction as
the steel tank. The vessel has threaded connections (type 316-L
stainless steel) which are welded to the tank and penetrate through
the lining. The water passage through the tank only comes in contact
with the STONESTEEL lining and the stainless steel threaded connections.
Most other manufacturers use steel threaded connections in their
tanks which is a clear source of tank failure.
What is the purpose of a tank lining? The tank lining is designed
to prevent corrosion in the steel tank. Most pressure vessels are
made of carbon steel which will rust rapidly if used with hot or
cold water. Over the years, a variety of tank linings have been
tried, some successful and others total failures. Any time a new
tank lining is introduced, it is always touted as the latest and
greatest but only the test of time will prove what type of tank
linings will hold up and which ones will not.
Galvanizing. A galvanized steel tank is produced
by dipping the steel tank in a bath of molten zinc. When the tank
is removed, the zinc solidifies. The zinc acts sacrificially to
the steel, preventing corrosion of the water tank. The zinc lasts
for several years at which point rusty water is evident and the
tank rapidly fails.
Glass lining. Steel tanks are lined with a
porcelain enamel. The interior of the vessel is sprayed with a porcelain
enamel frit and is then baked (heated to a temperature between 1400
and 1600o F) which melts the frit and bonds same to the
steel tank. The vessel is then cooled. All glass lined tanks require
a magnesium anode, since the porcelain enamel has tiny pinholes
throughout. The magnesium anode acts sacrificially to these pinholes
in the lining and prevents corrosion. When the magnesium anode dissolves,
the tank is subject to corrosion. The anodes can be replaced on
a periodic basis, but this is typically a maintenance item
that goes unnoticed and does not get done.
Copper lining. Steel tanks made with sheet copper
tack welded to the interior of the vessel. In as much as copper
and steel expand and contract at different rates, expansion joints
are required. A copper lined tank requires a vacuum breaker to prevent
the copper lining from pulling away from the wall while draining
the tank. Copper lined tanks are very expensive and are not widely
used in North America.
Nickel phosphate lining. This lining consists
of the chemical deposition of nickel salts and phosphate compounds.
This coating method results in about a 3 mil thickness of the nickel
phosphate lining. As with glass lining, the material can still have
some small pinholes as the material is porous and it cannot be produced
pore free. Nickel phosphate lined tanks are then coated with one
or more coats of amine cured epoxy lining. There is only one manufacturer
of nickel phosphate lined hot water tanks in the United States.
Other manufacturers have refrained from offering this lining type
as they feel other linings are much more suitable for hot water.
Epoxy lining. Tanks coated with a catalytic
amine cured epoxy paint. Surface preparation is very important in
applying the epoxy lining. The epoxy lining is a very hard and brittle
material and possesses a different rate of expansion and contraction
than the steel tank which may lead to the lining cracking. If the
lining cracks and any water seeps into or behind it, the lining
tends to fall away.
CEMLINE CORPORATION has been manufacturing it's STONESTEEL hot
water tanks since 1935. A STONESTEEL hot water tank is corrosion
resistant and should last the life of the building. We are aware
of numerous STONESTEEL hot water tanks installed and running for
over 50 years and are still producing hot water without rust. The
hydraulic cement lining has the same coefficient of thermal expansion
and contraction as the steel shell. The lining is applied to a thickness
of 3/8" to 1/2", which results in no pinholes, thus no magnesium
anode is required. Specified and used throughout North America,
STONESTEEL is the premier tank lining for hot and cold water
tanks.
