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Commercial buildings can pose a variety of issues for insulation contractors.
Examples of mechanical applications requiring insulation on these projects include: low-pressure steam/condensate, hot water, cold water, and air-conditioning lines; heating hot water, supply and return chilled water, and refrigerant lines; and supply and return outside air and exhaust air systems.
Commercial building projects typically differ from industrial projects in the following characteristics:
The 3 biggest issues the insulation contractor faces on commercial jobs are:
When specifying the best insulation for these applications, the design engineer/contractor first looks at performance compliance, which would include meeting all state and local building code requirements. The insulation materials must be able to withstand the temperatures and environmental conditions of the particular application. Different regions of the country—e.g., north versus south, or inland versus coastal areas—may require different materials for the same application because of the different environmental conditions, such as higher humidity in southern and coastal areas. This is particularly true for below-ambient systems, such as chilled water, where both surface condensation (sometimes called casual or intermittent condensation) and condensation within the insulation area (which can be caused by an inadequate moisture vapor seal on all joints, longitudinal seams, fittings, hangers, and termination points) constitute a key concern. These must be addressed in the design parameters. When the building envelope is not dried-in, it is important that the engineer specifies insulation materials with low water-absorption characteristics and insulation systems with a low water-vapor permeability.
When specifying the best insulation for these applications, the design engineer/contractor first looks at performance compliance, which would include meeting all state and local building code requirements. The insulation materials must be able to withstand the temperatures and environmental conditions of the particular application. Different regions of the country—e.g., north versus south, or inland versus coastal areas—may require different materials for the same application because of the different environmental conditions, such as higher humidity in southern and coastal areas. This is particularly true for below-ambient systems, such as chilled water, where both surface condensation (sometimes called casual or intermittent condensation) and condensation within the insulation area (which can be caused by an inadequate moisture vapor seal on all joints, longitudinal seams, fittings, hangers, and termination points) constitute a key concern. These must be addressed in the design parameters. When the building envelope is not dried-in, it is important that the engineer specifies insulation materials with low water-absorption characteristics and insulation systems with a low water-vapor permeability.
After reviewing the insulation
materials, one may find that there are 2 or 3 that meet the performance
criteria needed. Thus, the next step in the selection process is to select the
most cost-effective material, which is often decided by which product is most
easily installed or will last the longest with little or no maintenance.
This article will address the
unique circumstances of commercial buildings that will determine performance
and cost effectiveness.
Note that the building owner needs to differentiate between lowest first-cost materials and lowest life-cycle cost materials, since these are often not the same. Then, they must convey their requirements to the specifying engineer.
On hot systems, the following materials are often specified and installed: :
For hot applications, fiberglass with ASJ has the benefits of performance, ease of installation, and cost effectiveness. For below-ambient systems—i.e., cold or chilled water—design engineers routinely select closed-cell insulation materials with an inherent low water vapor permeability value, particularly in unconditioned spaces, because of their concern over condensation control and long-term thermal performance. This group of materials would include cellular glass, elastomeric foam, phenolic foam, polyolefin, polystyrene, and polyisocyanurate (PIR) foam insulations. Fiberglass continues to be specified and successfully used on below ambient systems in continuously conditioned spaces such as occupied offices, where humidity is low and there is less vapor drive, typically in the northern regions. For unconditioned spaces, it is recommended that fiberglass with ASJ be covered with a continuously sealed polyvinyl chloride (PVC) jacket.
Another consideration to take into account is environmental fluctuations during use in a particular space. For instance, a conditioned convention center hall may experience major variations in ambient conditions during loading or unloading, when the shipping doors are wide open. The proper insulation for this type of condition must be selected or the building’s systems may face problems. A similar situation can occur when the convention center is not in use and the HVAC system is turned off, causing a significant rise in indoor conditions.