The Truth About Service Temperature For VRF/VRV System Insulations


The service temperature of VRF/VRV System insulation is not directed by refrigerant pressure/temperature tables or pipe service pressure ratings, as asserted by certain elastomeric insulation producers. These insulation producers are implying that it is acceptable to ignore the requirements of the equipment producer’s installation manuals. The service temperatures for pipe insulation applied to these systems are detailed by the system manufacturers in their installation manuals. The upper service temperatures are specifically detailed at 248°F or higher for manufactures that make up the majority of the industry. Rebranded systems carry the same requirements as the main line brand. One major producer of VRF requires a minimum upper service temperature of 248°F on certain systems and 227°F on others, still eliminating the use of NBR/PVC elastomeric insulation products. Another major name requires 212°F or hotter. Two producers specifically detail that the insulation is to be EPDM. One of these producers also requires a material suitable for use in plenums. This eliminates products that do not have a continuous use temperature of +250°F or higher. Most of the service temperatures required precludes using anything except EPDM for elastomeric insulation, and all upper service temperature requirements eliminate the use of polyethylene.

One NBR/PVC insulation producer claims to have testing to 250°F per ASTM C 411. The data sheet for the product claims 220°F on an intermittent or “spike” temperature basis, with 180°F being considered a constant service. This does not meet the requirement of a material that is rated at 248°F or greater service temperature. Additionally, the material is not an EPDM product as detailed by two system manufacturers. Based on the requirements of system installation manuals, the product is not an acceptable product for use on VRF/VRV systems. Another NBR/PVC elastomeric producer doesn’t even try to allude to achieving the required 248°F. Contractors and designers who use materials with lower maximum service temperatures than are detailed in the installation manuals will have little recourse on failures of any kind. The system manufacturer can say that the correct material was not used.

Cold service is critical, because of the extremely low operating temperature needs of a VRF/VRV system. The coldest temperature that is specifically detailed is -4°F. Aerocel, using standardized testing and in practical applications, excels at temperatures as low as -320°F. NBR/PVC producers do not address cold service needs with VRF/VRV systems, including resistance to moisture intrusion in liquid or vapor form.

One NBR/PVC producer asserts that VRF/VRV manufacturers detail “…insulation specifically designed to be used in an HVAC system…” This is not the case. The materials detailed can serve in many systems, including HVAC systems. Two producers of VRF systems both specifically require foam insulation materials, with one going as far as to say closed-cell foam. Again, two system producers detail the material to be EPDM. Another allows fibrous or foam insulation materials that meet the other performance measures detailed. The cold-operation service temperatures and foam requirements preclude the use of fibrous materials. If the material can provide the performances needed, then it is usable.

Other Key Needs of VRF/VRV Insulation Ignored by NBR/PVC Producers

Resistance to UV – Much VRF/VRV piping is installed outdoors. The insulation system HAS to resist the effects of weather, especially UV degradation. LG specifically details that protection from weathering required. Only EPDM provides this protection without added treatment, including resisting UV degradation.

Water Vapor Transmission – These are very cold systems, with very high vapor drives. Resistance to water vapor is critical to long-term service. EPDM has the lowest WVTR.

Contribution to Corrosion – These systems are being piped with specialty materials. These systems will have a greater affinity for condensation. These systems are installed outdoors in rain, snow and ice. All the above add up to conditions that will cause corrosive components of insulation systems to leach, and contribute to premature piping system failure due to external stress corrosion cracking or pitting corrosion failure. NBR/PVC is known to contribute to corrosion failure of systems. EPDM has been demonstrated not to contribute to corrosion on multiple occasions.

Sizes Needed – Codes are requiring greater thicknesses, for both the cooling and HEATING modes of operations. VRF/VRV run unique and very small OD pipes. Small ID/thick wall insulation is needed. Aerocel provides the sizes needed, including 1/4” ID.

LEED/Low VOC Projects AC and SSPT with Cel-Link II, meet the need for low or no emission of volatile organic compounds or formaldehyde gas. Aerocel EPDM insulation meets the need for sustainable construction requirements.

Life Safety Considerations VRF systems are widely used in high-occupancy buildings that require exceptional fire-safety. Aerocel EPDM insulation is lower than ASTM E 84 25/50 flame and smoke ratings, and is rated by ASTM D 635 as Self-Extinguishing, delivering exceptional fire safety properties.

More information about how Aerocel® EPDM is the perfect fit for VRF/VRV ductless split systems can be found at:

About Aeroflex USA, Inc.:
Aeroflex USA, Inc. is the leading United States producer of EPDM flexible cellular rubber insulation products. Aeroflex USA, Inc.’s facilities are in Sweetwater, TN, where these insulation products are produced and distributed to North, Central and South America. Aeroflex USA, Inc. started in business in 1999, and is a subsidiary of Eastern Polymer Group, Bangkok Thailand. Eastern Polymer Group is the world’s leading producer and developer of EPDM rubber products used for thermal and acoustical insulation. Further contact with Aeroflex USA, Inc. may be made by e-mailing or calling 1-866-AEROCEL (1-866-237-6235).