Chemical Engineering October 2010 - 34

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Industrial Insulation Systems:
Material Selection Factors
To provide the desired functions while being
exposed to harsh environments, insulation
material should be carefully selected and
specified to meet the design goals
Gordon H. Hart
Artek Engineering, LLC
David W. Yarbrough
R&D Services, Inc.
T
hermal insulation systems can
provide several functions on piping
and equipment in industrial
facilities. Some of these are: reduction
in energy loss, process control,
personnel protection, emissions reduction,
condensation, freeze protection,
and noise reduction. In the chemical
process industries (CPI), thermal insulation
systems are often subjected
to severe environments that might
include either very high or very low
service temperatures, weather exposure,
physical abuse, exposure to corrosive
chemicals, and, in an accident
scenario, fire. To provide the desired
functions while being exposed to these
environments over a long time period,
the insulation materials should be
carefully selected and the installation
details specified to assure that the design
goals are met. In industrial facilities,
this can be challenging.
Reasons foR insulating
The reasons for insulating pipes and
equipment can vary from system to
system and from facility to facility. The
first inch of thermal insulation usually
reduces heat loss by at least 85% and
several inches usually reduces it by
about 95% compared to what it would
be from uninsulated surfaces. This insulation
thermal performance, in turn,
allows the facility owner to achieve
several goals, including the following:
Figure 1. This
photo shows insulated
pipes with
metal jacketing over
the insulation. Due
to the lack of dents,
this insulation
probably insulates
as well as it did
when first applied
* To control process temperatures, a
necessity for the plant to successfully
achieve production and quality goals
* To control energy costs
* To provide personnel protection on
above-ambient service temperature
systems by keeping the surface temperatures
below the maximum design
value, often 130-140°F when
protected with sheet-metal jacketing
* To reduce greenhouse gas emissions,
such as CO2, by significantly reducing
heat loss compared to uninsulated
surfaces
* On below-ambient systems, to minimize
surface condensation of water
from the surrounding ambient air.
This, in turn, prevents further waste
of thermal energy and prevents wet
walking surfaces, located beneath
the cold surfaces, that can pose a
danger to plant personnel
* In geographic areas where air temperatures
may dip well below freezing
for extended periods of time, to
prevent either freezing of the liquid
in the process pipes or a decrease
of the liquid's viscosity to a point
where it can no longer be pumped
* Properly designed, to provide sound
control by helping to absorb emitted
noise
34 ChemiCal engineering www.Che.Com oCtober 2010
* To provide fire protection, against
petrochemical fires, for specified periods
of time, such as 1 or 3 h
These are the usual objectives in insulating
piping and equipment at industrial
facilities. A wide variety of
insulation materials and accessories
are available to accomplish them.
MateRials and
accessoRies
The components making up thermal
insulation systems can be categorized
as follows: thermal insulation, protective
jacketing, water vapor retarders,
sealants, mastics, adhesives and cements,
and attachments. Each of these
materials provides an important function
in the insulation system in which
they are used.
Above ambient materials, design
The thermal insulation material is
what provides the energy savings.
Every different material has a temperature
versus thermal-conductivity
curve, which can be used in calculations
to determine the required insulation
thickness for targeted energy
savings. While some materials have
much lower thermal conductivities
than others in the temperature range
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Chemical Engineering October 2010

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