\ninstallation start to completion;<\/p>\n
<\/UL><\/p>\n
The 3 biggest issues the
\ninsulation contractor faces on commercial jobs are:<\/p>\n
- <\/p>\n
- Making
\nsure the building is enclosed (i.e., the roof is installed and the building is
\nwater tight) before insulation installation starts. This may not always be
\nfeasible since the insulation contractor does not control this.<\/p>\n - Ensuring
\nthe design engineer and other trades (pipe\/duct mechanical contractors) provide
\nclearance between pipes and walls for the insulation thickness specified.<\/p>\n - Working
\nwith the schedules of the other mechanical and plumbing contractors.<\/p>\n<\/OL><\/p>\n
When specifying the best insulation for these applications, the design
\nengineer\/contractor first looks at performance compliance, which would include
\nmeeting all state and local building code requirements. The insulation
\nmaterials must be able to withstand the temperatures and environmental
\nconditions of the particular application. Different regions of the
\ncountry—e.g., north versus south, or inland versus coastal areas—may require
\ndifferent materials for the same application because of the different environmental
\nconditions, such as higher humidity in southern and coastal areas. This is
\nparticularly true for below-ambient systems, such as chilled water, where both
\nsurface condensation (sometimes called casual or intermittent condensation) and
\ncondensation within the insulation area (which can be caused by an inadequate
\nmoisture vapor seal on all joints, longitudinal seams, fittings, hangers, and
\ntermination points) constitute a key concern. These must be addressed in the
\ndesign parameters. When the building envelope is not dried-in, it is important
\nthat the engineer specifies insulation materials with low water-absorption
\ncharacteristics and insulation systems with a low water-vapor permeability.<\/span><\/p>\nAfter reviewing the insulation
\nmaterials, one may find that there are 2 or 3 that meet the performance
\ncriteria needed. Thus, the next step in the selection process is to select the
\nmost cost-effective material, which is often decided by which product is most
\neasily installed or will last the longest with little or no maintenance. <\/p>\nThis article will address the
\nunique circumstances of commercial buildings that will determine performance
\nand cost effectiveness. <\/p>\nNote that the building owner
\nneeds to differentiate between lowest first-cost materials and lowest
\nlife-cycle cost materials, since these are often not the same. Then, they must
\nconvey their requirements to the specifying engineer.<\/p>\nOn hot systems, the following
\nmaterials are often specified and installed:<\/p>\n- <\/p>\n
- Low-pressure steam and condensate—fiberglass with all-service jacketing
\n(ASJ)<\/p>\n - Hot water—fiberglass with ASJ (hot water is sometimes subcontracted out
\nby the plumbing contractor to an insulation subcontractor). In addition,
\nclosed-cell insulations are sometimes used when the mechanical engineer does
\nnot want to mix materials on domestic hot- and cold-water applications. <\/p>\n<\/UL><\/p>\n
For hot applications,
\nfiberglass with ASJ has the benefits of performance, ease of installation, and
\ncost effectiveness. <\/p>\nFor below-ambient systems—i.e.,
\ncold or chilled water—design engineers routinely select closed-cell insulation
\nmaterials with an inherent low water vapor permeability value, particularly in
\nunconditioned spaces, because of their concern over condensation control and
\nlong-term thermal performance. This group of materials would include cellular
\nglass, elastomeric foam, phenolic foam, polyolefin, polystyrene, and
\npolyisocyanurate (PIR) foam insulations. Fiberglass continues to be specified
\nand successfully used on below ambient systems in continuously conditioned
\nspaces such as occupied offices, where humidity is low and there is less vapor
\ndrive, typically in the northern regions. For unconditioned spaces, it is
\nrecommended that fiberglass with ASJ be covered with a continuously sealed
\npolyvinyl chloride (PVC) jacket. <\/p>\nAnother consideration to take
\ninto account is environmental fluctuations during use in a particular space.
\nFor instance, a conditioned convention center hall may experience major
\nvariations in ambient conditions during loading or unloading, when the shipping
\ndoors are wide open. The proper insulation for this type of condition must be
\nselected or the building’s systems may face problems. A similar situation can
\noccur when the convention center is not in use and the HVAC system is turned
\noff, causing a significant rise in indoor conditions.<\/p>\nIn Figure 1 the author shows
\nsome types of insulation materials listed by application. Not all insulation
\nmaterials are listed, however; readers should research what is best for their
\nindividual project.<\/p>\nPerformance issues unique to below-ambient
\nsystems in commercial buildings that would factor into the material selection
\nprocess may include:<\/p>\n- <\/p>\n
- Susceptibility of mold growth on enclosed piping (behind walls). This is particularly a problem with paper-faced vapor
\nretarders in unconditioned spaces. The concern over mold issues in this type of
\napplication may lead to more expensive and more labor-intensive insulation
\nsystems being used to reduce potential future problems.<\/span><\/p>\n- Susceptibility of vapor barrier damage in pipe chases where material must
\nbe applied and slid through penetrations. This would limit maintenance after
\ninstallation. Some insulation materials require the specification of a robust
\njacket capable of withstanding abuse; PVC jacket is sometimes used for this
\nreason. Multi-layer (low perm) jackets with easy-to-seal seams that resist
\nabuse may be used where maintenance of the system will be limited or
\nnon-existent.<\/p>\n- Temperature and humidity not regulated
\nuniformly throughout the building may require the use of greater insulation thickness
\nto prevent condensation in some parts of the building (e.g., back room or
\nceiling areas).<\/span><\/p>\n- Prevention of water vapor
\ncondensation\/intrusion within the insulation and on the metal pipe and
\nequipment surfaces, requiring that all insulation systems be completely sealed
\nagainst water vapor intrusion. In this case, only insulation systems capable of
\nbeing continuously sealed should be selected. An often misleading concept is
\nthat all jacketing provides a moisture\/moisture vapor barrier. Metal jacketing,
\nsuch as aluminum, only provides a moisture vapor barrier if all seams and any
\npenetrations (e.g., rivet holes) are caulked; therefore, metal jacketing is
\nintended to be protective and not as a vapor retarder material. Additionally,
\nPVC jacketing will only be effective as the water vapor transmission barrier of
\nthe seams. Flexible laminate jacketing, some with a zero permeance rating, must
\nbe continuously sealed, usually with a compatible, zero permeance, pressure
\nsensitive tape.\u00a0 Rewettable fiberglass cloth provides abuse protection only and
\nis not a vapor retarder barrier. For below-ambient systems, the insulation
\nbeneath the jacketing should provide a moisture vapor barrier on its own.<\/span><\/p>\n<\/UL><\/p>\n
Installation issues unique to
\nbelow-ambient systems in commercial buildings may include:<\/p>\n- <\/p>\n
- Insulation being installed prior to the building being enclosed. This is
\na quite common, but counterproductive, practice. Closed-cell foam materials are
\ncapable of withstanding intermittent moisture or high-humidity conditions that
\nmay be present during the construction of the building, but this is often not
\nfactored into the engineering design specification. Closed-cell foam insulation
\nproducts are sometimes specified or used for this reason, such as in hotels
\n(duct risers).<\/p>\n - The need for a flexible insulation material for installation around and
\nthrough walls, including air-conditioning lines, chilled water run-outs, etc.
\nNote: Air-conditioning lines are typically completed by the
\nmechanical\/equipment installer.<\/p>\n?
\n<\/span>The need to meet a compressed
\ninstallation time schedule. Installation products with adhesive, pre-applied,
\npre-fabricated fittings, or insulation with pre-applied jacketing, are often
\nused to shorten the installation time. These products may also reduce the risk
\nof failures at the seams and joints of the insulation or the jacketing. Seams,
\njoints, jacketing, or adhesives applied in factory-controlled conditions may
\nperform better than those applied in the field under varying environmental
\nconditions. <\/span><\/p>\n- Ability of the insulation to be slid on the copper pipe in long sections
\n(20 inches) to eliminate butt joints and speed installation time, often a
\nconcern in supermarkets. Note: Supermarkets are generally done by the
\nrefrigeration contractor.<\/p>\n- Burial applications that require a load-bearing capacity as well as
\nbeing water tight.<\/p>\n- Extreme high-humidity applications may require low water-vapor
\ntransmission insulation and an additional ?low permeance, continuously sealed?
\njacket to prevent long-term water-vapor penetration.<\/p>\n- Prevention of pipe and equipment
\ncorrosion, sometimes called corrosion under insulation or CUI, in cold storage
\napplications (using ammonia systems) should receive extra care. Polystyrene and
\nPIR jacketed sealed with a low permeance vapor retarder have a long history of
\nuse. <\/p>\n<\/UL><\/p>\n
As seen in the examples, there are many reasons an insulation system is
\nselected for a particular application. Performance parameters should always be
\nthe highest priority, with other factors also coming into play (cost of
\nmaterial, installation technique, installation ease\/time, durability of the
\nmaterial over time, etc.). Lastly, experienced contractors become familiar with
\ninstalling specific materials on certain types of systems. Insulation and
\naccessory manufacturers are continually trying to refine their products for
\nbetter performance and ease of installation. They understand that one insulation
\nmaterial or one insulation system will not work best for all applications,
\nwhich results in niche products for specific applications. Commercial
\napplications tend to be more diverse and open to variation in design than
\nindustrial applications. Design engineers and insulation contractors should
\nalways be attentive to new products and processes if they want to stay
\ncompetitive and provide the best materials for an application.<\/span><\/p>\n - Ability of the insulation to be slid on the copper pipe in long sections
- Susceptibility of vapor barrier damage in pipe chases where material must
- Susceptibility of mold growth on enclosed piping (behind walls). This is particularly a problem with paper-faced vapor
- Low-pressure steam and condensate—fiberglass with all-service jacketing
![](\"https:\/\/insulation.org\/wp-content\/uploads\/2017\/06\/IO130904_01.jpg\")
<\/a>Figure 1<\/b><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"