Photo Gallery D3: Wet Insulation
Wet, discolored, stained, or water marked insulation is the first sign of “insulation failure” and potentially an external pipe corrosion condition. This is caused by inadequate, improperly installed, poorly maintained, or inappropriate insulation having allowed moisture to penetrate to the cold pipe surface. Although touted as a “moisture barrier” by manufacturers and others in the trade, the paper foil backing common to fiberglass products is actually quite poor, and will inevitably allow moisture to pass through. Once moisture reaches the pipe it condenses into water and then travels its most favored path to impact a much larger volume of pipe. Water droplets on the floor unquestionably define that the insulation has failed, is saturated, and that it can hold no more water. Although termed “insulation failure,” the issue is actually due to improper insulation methods themselves.
Various factors influence this condition – the most significant being insulation thickness, pipe temperature, and area moisture content. Properties in coastal areas such as Miami, Houston, New Orleans, and Puerto Rico are especially prone to this problem. Supply side pipe at typically a 10° F. lower temperature, will exhibit the worst impact since it attracts and condenses more moisture. Similar to weathering at an outdoor steel condenser water system, the problem is almost always immediately apparent. Brown spots, water marks, discolorization, and crystalization deposits are clear indications of the same issue. One exception to this rule is for soft rubber or foam insulation which not only traps condensed water inside, but also rarely shows any discolorizaton to its black surface.
Covering fiberglass insulation in vinyl or metal greatly improves its appearance, but also conceals any deficiency present. More often added for aesthetics rather than function, the seams are rarely if ever silicone sealed; a critically necessary step in utilizing such outer covering as an effective moisture barrier. Without an effective seal at every seam, moisture inevitably migrates inside – its further damage now hidden from view. Sufficient water can be stored within plastic insulation coverings and soft foam insulation to suggest that cutting through the insulation actually cut through the pipe itself. For grooved pipe construction, the elongated ring enclosing every clamp can easily fill with water to then impact the clamp itself.
For one client where this condition led to a clamp retaining bolt corroding through, the clamp separate to catastrophically dump the entire contents of the chill water system through a now fully open 8 in. distribution line. For another, the condition was identified just in time to prevent a similar event.
Other threats exist related to the fact that paper and fiberglass offer excellent growth substrates for mold; introducing a health threat to all building occupants. Once the insulation is wet and saturated with water, its R value plummets to provide almost no benefit, as well as increasing energy costs.
Once wet insulation is identified, further investigation should be conducted in order to identify the level of impact to the pipe followed by its replacement with the correct material. If moderate to heavy external pipe damage has occurred, further action such as pipe rehabilitation or replacement may be required depending on its severity.
