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Low temperature buildings used for food processing,
storage and other applications create one of the most hostile
environments to which insulation can be subjected. Such buildings,
in order to serve their intended purpose, must maintain interior
temperatures that are cool, sub-freezing, or even sub-zero.
Under these conditions, it is critical that the building wall,
roof and floor insulation possess superior water resistance
qualities and stable reliable R-value. These are the attributes
that make extruded polystyrene (XPS) the preferred insulation
for low temperature buildings. XPS is an insulation that will
endure the low-temp environmental demands while enabling
the economical maintenance of a low temperature interior.
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The design
of concrete slab floors
in low temperature buildings
is also influenced by the static and dynamic loading
on the slab, and, by the compressive strength and
foundation modulus of the sub-grade XPS insulation.
The deflection of the sub-grade XPS and the flex
tolerance of the slab under load must be carefully
engineered to insure long-term durability.
Insulating low temperature building floors presents
an especially demanding
challenge. Not only must
they be insulated to
minimize heat gain into the building, and minimize
below floor freezing, but they also must often meet
high load requirements for storage and forklift operation.
XPS is virtually the only insulation used in this
application due to its high stable R-value, superior
moisture resistance, and due to the variety of high
compressive strength products available. |
The constant low interior temperature in low-temp buildings creates
moderate to high temperature differential and moderate to high vapor
pressure differential between inside and the sub-grade below the
floor. Insulation below low-temp floors must provide stable insulation
value to prevent ground freezing and subsequent damage to the building
floor. Ground freezing/icing can occur when the interior cold temperature
draws ground moisture toward the cold concrete floor slab. Because
of this constant flow of moisture to the cold floor surface, the
XPS insulation must be capable of maintaining R-value in the presence
of moisture. Sometimes in sub-freezing buildings, the insulation
must be accompanied by anti-icing or below grade heating systems.
Heat flow out of the ground can eventually result in a frozen sub-grade
unless some heat is mechanically replaced. XPS insulation is an
integral part of keeping the balance between interior low temps
and a well protected sub-grade.
Durable XPS stands up to the
rigors of jobsite handling and is available in
a variety of sizes and thicknesses. XPS insulation
boards are available in a broad range of compressive
strengths—15, 25, 40, 60 and 100 psi—sufficient to suit most,
if not all, below-grade design requirements.
Extruded
polystyrene insulation (XPS) is by far the preferred
choice for use in low temperature buildings and
floors because of it’s strength,
high resistance to moisture absorption, and,
because of it’s
ability to maintain R-value in the presence
of moisture. Lasting R-value is essential to
controlling the long-term operating costs of
low temperature facilities.
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