UV-Resistant Refrigerant Line Insulation

Refrigerant piping must often be installed in building exteriors, such as rooftops, to convey refrigerants between large roof-top HVAC systems and interior equipment to provide conditioned air to the building’s occupant spaces and equipment.

U.S. commercial energy codes and standards, such as ASHRAE 90.1 Energy Standard for Buildings Except for Low-Rise Residential Buildings, International Energy Conservation Code® (IECC®), require refrigerant piping to be insulated. The codes and standards do specify the insulation thickness based on pipe size and line temperature, however, they do not specify the insulation type. This is where UV-resistant refrigerant line insulation plays a critical role.

The energy codes and standards referenced above also require “protection from damage” when exposed to the weather. Factors that can damage refrigerant line insulation include sunlight, moisture, severe weather, equipment maintenance, varmints, and birds. Yes, birds love insulation for nest-building!

With so many types of refrigerant pipe insulation to choose from (fiberglass, closed-cell flexible elastomeric foam, phenolic foam, polyisocyanurate, and cellular glass to name a few), how does a mechanical engineer choose the best UV-resistant refrigerant line insulation for their client?

While first cost (initial material and labor cost) are always a top concern to meet project budgets, other important factors such as energy efficiency, durability to exterior exposure, maintenance/repair, and replacement costs must also be evaluated.

Closed-cell flexible elastomeric foam pipe insulation has been a proven refrigerant line insulation solution in the U.S. for close to 70 years. Due to its lightweight closed-cell structure, built-in vapor retarder, excellent condensation control performance, flexibility, favorable thermal conductivity, national availability, and moderate cost, closed-cell flexible elastomeric foam is often specified to insulate commercial and industrial refrigerant piping.

While other insulation types do require protective jacketing for interior and exterior installations, closed-cell flexible elastomeric foam refrigerant line insulation does not require protective jacketing for most interior applications. However, closed-cell flexible elastomeric foam refrigerant pipe insulation can be subject to mechanical damage and UV degradation in exterior applications over time.

The following national and state energy codes/standards specifically require protection of insulation as follows:

IECC-2018 C403.11.3.1 Protection of piping insulation (Mandatory)
“Piping insulation exposed to the weather shall be protected from damage, including that caused by sunlight, moisture, equipment maintenance and wind, and shall provide shielding from solar radiation that can cause degradation of the material. Adhesive tape shall not be permitted.”

ASHRAE 90.1-2019 6.3.2.l
“Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas, or plastic cover. Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation.”

California Title 24 – 2019 4.4.1.2.F.2
“Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation that can cause degradation of the material.”

The most common closed-cell flexible elastomeric foam refrigerant pipe insulation is composed of a nitrile butadiene/PVC rubber (NBR) base which is subject to UV degradation depending on the UV intensity that it is subjected to. Another option is Ethylene Propylene Diene Monomer (EPDM) which has greater UV resistance than NBR and degrades at a slower rate than NBR. For example, EPDM rubber is often utilized in vehicle components due to its favorable durability and resistance to heat, condensation, and UV exposure.

When any closed-cell flexible elastomeric foam refrigerant pipe insulation is installed in an exterior setting, it should be protected from UV exposure. While the Aeroflex® Aerocel® brand of EPDM closed cell flexible elastomeric foam refrigerant line insulation will degrade at a slower rate than NBR, it is not UV-proof. EPDM protective options include mechanical jacketing (i.e. metal or PVC) or Aerocel Aerocoat™ UV Protective Coating for energy code compliance. Since Aerocoat is specially-formulated to protect EPDM rubber through expansion and contraction cycles, it should not be substituted for standard white paint.

Aerocel’s UV-resistant EPDM refrigerant line insulation can deliver favorable life cycle costs to building owners when properly protected from the exterior elements. To learn more, visit https://www.aeroflexusa.com/aerocel-hvac-pipe-insulation.

Sources:
ASHRAE 90.1 Energy Standard for Buildings Except Low-Rise Residential Buildings
International Energy Conservation Code® (IECC®)
California Building Energy Efficiency Standards – Title 24