Sodium Hypochlorite Storage Tanks
Tanks for Sodium Hypochlorite must be able to withstand
the aggressive nature of the chemical involved.
Fiberglass or Poly?
Since Sodium Hypochlorite is such a poor match for steel
tanks, the natural choices have been either plastic or
fiberglass. Fiberglass tanks offer about the same lifespan
as plastic tanks when used for storage of Sodium
Hypochlorite but cost 30 to 40% more and require great care
against damage in shipping and use. As a result,
Polyethylene tanks hold much of the Sodium Hypochlorite used
by industry and water treatment operations today.
There are differences in Polyethylenes?
When you start looking for the right Polyethylene tank for
storage of Sodium Hypochlorite, things get a little tricky.
While resin maker Exxon has done studies with the University
of Nebraska, some tank makers continue to go against
recommendations from Exxon that result from that study. As
a result, you could be tricked into a bad choice of tank
materials and end up getting a tank that has a shorter
useful life than is otherwise available.
Density Polyethylene versus Crosslink Polyethylene.
several variations of Polyethylene. The two that come
into play with Sodium Hypochlorite are High Density
Polyethylene and Crosslink Polyethylene.
Crosslink is an older type of polyethylene that is more
expensive, not recyclable and is not ‘weld-able’ using
thermoplastic welding. It has advantages when it comes
to the storage of a few chemicals but, according to Exxon,
it is not the best choice for tanks that will store sodium
hypochlorite. Exxon’s study shows clear benefits from
using High Density Polyethylene for the storage of Sodium
can see the Exxon report at the Exxon web site by clicking
Location makes a difference!
the selection of High Density Polyethylene as the material
for the tank, the planned location also affects tank
Tanks where exposure to Ultra Violet rays will be low can be
manufactured from Natural color resin. It is a
translucent white and since you can see the level of the
liquid, there is no need for a sight gauge.
Tanks where exposure to Ultra Violet rays will be moderate
can be made from Black colored resin. The fill level
will not be visible so a sight gauge or other level
indicator is a very good idea.
tanks can be made from Natural color resin if they are going
to be coated with polyurethane foam insulation and covered
with a mastic coating. Fill level is not visible
through the foam.
Outdoor tanks that will
not be coated with insulation should be opaque.
Depending on the climate and degree of exposure to direct
sunlight, either a black or opaque white tank could be
grade of tank?
Polyethylene tanks are
manufactured and rated based on the weight per gallon of the
liquid they are able to hold. Beyond the weight of the
liquid, other factors such as the effect of the chemical on
the tank over time must be taken into account. We
recommend using tanks with a specific gravity of 1.9 or
higher for storing Sodium Hypochlorite.
are a whole separate discussion that we can easily work out
with tank selection and fittings, click here to e-mail us.
incude as much information as possible about the tank size
and concentration of sodium hypochlorite.
More detailed information is
available from our specialty web site: