Choosing the Right Refrigerant Pipe Insulation

refrigerant pipe insulation

Refrigerant pipe insulation is a critical component of refrigeration systems. Refrigeration systems, also known as below-ambient, vary by application (commercial and industrial), temperature requirements (high & low), refrigerant types (traditional and natural), and operating environments. Common refrigeration system applications include supermarkets, cold storage, food processing, beverage dispensing lines, ice rinks, morgues, laboratories, chillers, data centers, and owner-specific applications. While refrigerant pipe insulation is commonly installed indoors, many systems include piping and equipment on exterior rooftops to conserve interior space or to preserve interior design aesthetics.

Commercial and industrial refrigeration systems have a few things in common. They are demanding, designed to operate 24/7, may require wide temperature fluctuations, are designed to avoid costly downtime, and are always subject to a persistent enemy – moisture which can result in surface condensation. Condensation creates the potential for decreased thermal efficiency, pipe corrosion under refrigerant pipe insulation, icing, mold & mildew growth, and system failure.

Refrigerant pipe insulation plays a critical role in controlling heat gain of refrigerant fluids, moisture, surface condensation, and icing. National energy standards and codes require refrigerant pipe insulation on cooling systems, such as chilled water, brine, and refrigerants, that operate with service temperatures below 40°F (typically 20°F) and up to 60°F. However, some refrigeration systems operate as low as -50°F (ammonia) and up to 250°F (intermittent defrost cycles).

The proper refrigerant pipe insulation thickness, factoring in system operating conditions such as pipe size & type, ambient temperature, relative humidity, wind speed (if applicable), and jacketing, can be calculated to control surface condensation for the life of a refrigerant pipe insulation system.

The ASHRAE Handbook recommends closed-cell types of refrigerant pipe insulation for refrigeration system applications, such as cellular glass, flexible elastomeric, polyisocyanurate, and polystyrene, due to their low water vapor transmission (WVT), low water absorption qualities and not always requiring a supplemental vapor barrier. Important refrigerant pipe insulation selection considerations include the following reference standards (not all-inclusive):

  • Thermal conductivity (thermal k-value) / ASTM C518
  • Water vapor transmission (WVT) / ASTM E96
  • Water absorption / ASTM C209
  • Continuous service temperature / ASTM C411
  • Fire safety (25/50) / ASTM E84
  • Fungi resistance / ASTM G21
  • UV resistance / ASTM G7

Of the closed-cell refrigerant pipe insulation types referenced above, flexible elastomeric refrigerant pipe insulation has been commercially available in the United States for over 50 years and is a proven solution due to its closed-cell structure, built-in vapor barrier (smooth continuous outer skin), and flexible nature. American-manufactured flexible elastomeric insulation typically meets all of the above standards up to 2” thick (ASTM E84 25/50). While always available in a matte black, tubes are now available in white to blend in with commercial ceilings.

Additionally, flexible elastomeric refrigerant pipe insulation manufacturers offer their own system solutions such as insulated pipe hanger fittings to prevent moisture damage at pipe hanger locations (a common failure point due to compression of insulation from loaded pipes), special purpose contact adhesives (including low-VOC formulas), rubber/foam tapes and protective coatings.

To ensure the long-term performance of a flexible elastomeric refrigerant pipe insulation installation, it’s critical that all insulation seams are completely sealed with the manufacturer’s adhesive to provide a continuous vapor barrier. Additionally, closed-cell elastomeric foam insulation is susceptible to UV degradation when installed in exterior environments such as commercial rooftops. Refrigerant pipe insulation should be protected from solar radiation with the manufacturer’s specially-formulated protective coating (meets national energy code requirement) or jacketed if mechanical damage is expected (foot traffic, birds, varmints, or severe weather).

Aeroflex’s Aerocel® brand of refrigerant pipe insulation is American-made in Sweetwater, Tennessee, meets the referenced industry standards, and is composed of an EPDM rubber. EPDM offers a higher continuous service temperature and slower UV degradation rate than traditional NBR/PVC. EPDM is hydrophobic (does not induce or react to moisture) and is naturally microbial-resistant (no biocides added).

Aerocel REF™ is our standard formula for refrigerant pipe insulation and is available in unslit tubes or “factory-split self-seal” tubes known as Aerocel-SSPT™. For demanding applications, such as low-temperature refrigerant pipe insulation in high-temperature and humid operating environments, Aerocel ULP® (Ultra-Low Perm) offers a water vapor permeability rating of 0.01 perm-inch (standard flexible elastomeric formula perm ratings are 0.03 perm-inch, cellular glass @ 0.00) and a continuous service temperature on the low end of -320°F. Available thicknesses range from ⅜” to 2” and tube ID’s from ¼” to 16” IPS for both formulas.

To learn more about Aeroflex’s refrigerant pipe insulation solutions, please click here.

 

Source: https://insulation.org/io/articles/understanding-thermal-systems-basic-cooling-systems/