Adhesives, such as low VOC insulation adhesives, play a critical role in the installation of common mechanical pipe insulation applications such as:
- VRF pipe insulation
- VRV pipe insulation
- Refrigeration pipe insulation
- Refrigerant pipe insulation
- Chilled water insulation
- HVAC refrigerant pipe insulation
- HVAC refrigerant line insulation
- AC return line insulation
- Plumbing pipe insulation
Of course, insulation adhesives are intended to bond adjoining longitudinal seams and butt joints of pipe insulation. Manufacturers also formulate their low VOC insulation to provide vapor seals at insulation seams and termination points to prevent the ingress of air and water vapor into the pipe insulation system.
Moisture that gets trapped beneath insulation can catalyze a very real phenomenon called corrosion under insulation (CUI). When moisture comes in contact with a metallic pipe surface (i.e. copper or iron) and the contaminants on the pipe surface known as corrosion accelerators, the corrosion process begins and will slowly degrade the pipe surface, eventually leading to pipe and insulation system failure. CUI is a very costly and time-consuming process that is preventable.
Low VOC insulation adhesives are typically contact-based and available in solvent plus low-VOC formulations. When contact adhesives are applied to adjoining insulation surfaces, they require time to “tack up” prior to bonding the two surfaces together so the solvents can “flash off”.
Tack times vary depending on the adhesive type and job site conditions. Solvent-based formulas tack up faster than their low-VOC counterparts so they are usually preferred by mechanical insulation contractors. Since low VOC insulation adhesives contain varying levels of water instead of solvents, they require a slightly longer tack time.
Low VOC insulation adhesives that are contact-based can be formulated differently so it’s important to read the manufacturer’s installation instructions. For example, some contact adhesives must be “tacky-to-the-touch” prior to joining both surfaces together. The freshly-glued seams also cannot be taped or coated for 24-36 hours.
Other low VOC insulation adhesives must be “dry-to-the touch” prior to being joined together. This technology does not require additional “flash time” so the glued seams can be taped or coated over immediately.
Depending on the application, closed cell elastomeric insulation manufacturers may require that glued seams be covered with their elastomeric tape for additional vapor drive protection. Contractors may also voluntarily choose to apply tape over glued insulation seams to reduce callbacks.
For exterior installations, closed cell elastomeric insulation manufacturers may require that their UV-resistant coating be applied to prevent solar radiation degradation over time. Depending on the low VOC insulation adhesive installed, required dry times can vary from immediate to 7 days (full-spread adhesive on sheets or rolls). Be sure to check the manufacturer’s installation instructions on the product data sheet and low VOC adhesive label.
There continues to be a growing market demand for low VOC insulation adhesives due to green building rating systems such as the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED®). LEED-registered projects require low-emitting materials such as adhesives, sealants, and coatings.
A manufacturer’s low VOC insulation adhesive must be tested by a nationally recognized lab for two VOC thresholds – content and emissions. The intent with reducing VOC content is to protect the health of insulators and surrounding trades during installation. VOC emission reduction, on the other hand, is intended to reduce chemical emissions after installation to protect the health of building occupants.
Aeroflex USA offers Aeroseal LVOC™ Black Adhesive to meet low-VOC requirements when the Aerocel® brand of EPDM closed cell elastomeric pipe insulation is specified. This black low VOC insulation adhesive offers the benefit of being taped or coated over glued seams immediately after installation. The Aeroseal LVOC™ Black Adhesive data sheet and VOC test reports are available at: https://aeroflexusa.com/product_page/aeroseal-lvoc-adhesive/