In terms of preventing CUI, it is worth examining what tools are available to prevent it. There are a number of different tools that can be used, some more effective than others and all with limitations.
The first rule to understanding prevention is to keep water out of the insulation. Regardless of the type of thermal insulation, keeping water out starts with the protective jacketing.
The quality of the design, specification, procurement, installation, and maintenance of the protective jacketing system is always critical to preventing CUI. Standard 0.016-inch-thick aluminum jacketing, as well as steel sheet jacketing, installed with caulks and mastics, can effectively keep water out of the insulation system. To be effective, it is critical for everyone involved (the general contractor, insulation contractor, design engineer, and facility owner) to make certain that no shortcuts are taken in design, material specification, and installation. Both conventional aluminum jacketing and steel jacketing can be effective at keeping out the intrusion of water and preventing CUI. Hence, protective jacketing is the most important tool in the CUI prevention toolbox.
A new type of protective jacketing material that is seeing increasing interest is multilaminate, pressure-sensitive jacketing that can be purchased for either field installation or can be purchased factory applied to certain types of insulation. This family of materials essentially consists of industrial-grade tapes, available in 3 foot widths, that are weather resistant; impermeable to water or water vapor; resistant to many chemicals; and able to seal tightly with their pressure-sensitive, “peel-and-stick” surfaces.
Some of these are available in industrial-grade weights with a thickness of almost 0.016inches. An important accessory to making the system effective in keeping out water is a 2- to 4-inch-wide roll of tape to seal the joints and the penetrations. This type of material offers a jacketing that can be adhered to the insulation, thereby preventing moisture from accumulating between the jacket and the insulation. Its flexibility allows for easier installation and sealing at joints and penetrations as well as at termination points, making it very effective at keeping out water. Therefore, wide multi-laminate tapes should be included in the CUI prevention toolbox.
A third type of jacketing, that is durable and effective at keeping insulation beneath it dry, is a glass fiber lagging cloth with an acrylic weather coating mastic. This type of jacketing has the advantage of being able to seal penetrations effectively, to prevent water leakage. Another advantage is that is can be extremely durable, as well as being water proof. Therefore, lagging cloth with an acrylic weather coating mastic should be included as a tool in the CUI prevention toolbox.