Considerations for Insulation Specifications

Gordon H. Hart

Gordon H. Hart, P.E., is a consulting engineer for Artek Engineering, LLC. He has over 35 years of experience working in the thermal insulation industry. He is an active member of ASTM committees, including Committees C16 on thermal insulation and F25 on marine technology, ASHRAE's Technical Committee on Insulation for Mechanical Systems, and the National Insulation Association's Technical Information Committee. He received his BSE degree from Princeton University. and his MSE degree from Purdue University, both in mechanical engineering. He is a registered professional engineer. He can be reached at gordon.hart®

October 1, 2012

For a facility owner or manager, it is critical to know both
who is specifying your project and the contents of that specification. This is
extremely important in the case of mechanical insulation.

The facility owner has a
number of different resources available to him when he writes his
specification, or has it written by a engineer. These resources include a large
number of ASTM standards, the 2009 ASHRAE Handbook?Fundamentals; ASHRAE Standard
90.1-2010, Energy Standard for Buildings Except Low-Rise Residential Buildings;
the online Mechanical Insulation Design Guide; the National Commercial and
Industrial Insulation Standards, 7th Edition; the 3E Plus® computer
program; and others. Regardless of who writes the specification, they should
make use of these references and resources.

As everyone learns in Mechanical Insulation 101(e.g., NIA’s National
Insulation Training Program or the web-based Mechanical Insulation Education
& Awareness E-Learning Series), the facility owner first needs to know the
motivation for insulating. Is it for energy efficiency, process control, freeze
protection, personnel protection, condensation control, fire protection, noise
control, or some combination of these? Do all the surfaces specified with
insulation actually need to be insulated? If the answers to these questions are
not clear, then the facility owner needs to get answers to be able to proceed
to the next step and make certain that the specifier is designing the
insulation system with the same objectives in mind.

The specifier will need to
select particular materials. If the facility owner or manager has certain
preferences, these should be communicated to the specifier up front. If the
owner doesn’t have preferences, the next step is to confirm that the specifier
has answered certain questions before selecting materials. Here are few
questions that could be asked:

  • What
    are the maximum and minimum service temperatures for the surfaces being

  • Will
    those surfaces have cycling or steady temperatures?

  • Will
    the insulation system be located indoors or outdoors?

  • If
    located outdoors, will the pipe being insulated be above or below ground?

  • For
    below ambient systems located indoors, will the space be conditioned or
    unconditioned; and if the latter, is the local climate humid at least part of
    the year?

  • Will
    the insulation be subjected to foot traffic, regular vibration, or other
    physical abuse?

  • Will
    the insulation need to be removed periodically for mechanical maintenance or
    inspections and the insulation then reinstalled?

  • How
    long does the facility owner expect the insulation system to last?

  • For
    outdoor facilities, have steps been taken to guard against water leakage into
    the insulation system and subsequent possible corrosion under insulation (CUI)?

Once insulation materials
have been selected to the owner’s satisfaction, the owner should understand how
insulation thickness has been determined. If it is a commercial building and
energy efficiency is one of the reasons for insulating, then the owner should
make certain that the mechanical insulation meets the requirements such as
those in ASHRAE Standard 90.1-2010. (The 2013 version is in development.) If
the pipes to be insulated are part of an industrial facility, there are several
questions the owner should ask and the specifier should be able to answer.
Since the owner will be paying for facility energy use in future years, perhaps
most important pertains to energy efficiency and cost effectiveness: Are the
insulation thicknesses the optimum economic thicknesses for energy efficiency?
A second question would be: Are the insulation thicknesses sufficient to
maintain process temperatures as required by the industrial processes? If the surfaces
being insulated operate at high temperatures, are the insulation thicknesses
sufficient to protect personnel from being burned if they come in contact with
those surfaces? If the piping, equipment, and ducts operate at below ambient
temperatures in unconditioned spaces, the owner should make certain that the
insulation thicknesses are sufficient to prevent surface condensation up to 90%
relative humidity, as recommended by ASHRAE.

Finally, the facility
owner should know whether certain special design conditions have been
addressed. Here are a few examples of special conditions that could apply:

  • In the design plans, has sufficient clearance
    been left for insulation installation and maintenance?

  • If the insulation system is going to be exposed to
    certain corrosive chemicals that might damage the materials, have chemically
    resistant materials been specified?

  • If the insulated systems are located outdoors in a
    wet climate, have special design features been incorporated to guard against
    water intrusion and subsequent likelihood of CUI?

  • If frequent inspections and/or maintenance will be
    required on certain insulated components, have removable/reusable insulation
    materials been specified?

  • If horizontal insulated pipes are located close to
    the ground or other places where maintenance workers may walk on those pipes,
    have high compressive strength insulation materials been specified for those

  • Have insulated, below ambient pipe and
    equipment located in humid, unconditioned spaces been insulated with materials
    that will not support mold growth; and has special attention been paid to
    maintaining a sealed, low water vapor permeance for the insulation system?

  • If there is heat tracing, have the design plans and
    insulation sizes been correctly selected to allow for installation over the
    heat tracing?

list of special conditions could go on. Over time, if they have not been
adequately addressed in the insulation specification, the owner will probably
suffer the consequences. Those consequences could be greater than necessary
energy use, large-scale CUI, physically or chemically damaged insulation, wet
insulation, mold growth on insulation, high cost of removing insulation and
subsequent reinsulation with new materials, high insulation maintenance costs,
etc. It pays for facility owners to know the contents of their insulation
specification and to make certain it addresses their needs, both from the
beginning, when the facility is new, and through subsequent years of operation.
As a final caution, the facility owner must always guard against “value
engineering” the insulation systems, since that process all too often results
in short-term dollar savings but long-term increased expenses on energy,
insulation maintenance, CUI mitigation, and other operational costs.