Below-ambient systems create unique environments that have the potential for a multitude of issues, one of which is mold growth. Mold growth can occur either on or in
\nmechanical insulation on
\npipes and tanks if the right conditions are present. When mold grows inside duct work, it can be a very significant issue, and cause for concern. The conditions in ducts
\ncan be conducive for mold growth and the potential for health issues is high, particularly in schools, public buildings, and health-care facilities. Selecting the correct
\ninsulation type and installing it
\nproperly according to industry specifications and the manufacturer’s instructions can significantly decrease the probability of mold becoming an issue.<\/p>\n
In the past 15 years, the concern over mold has increased in large part due to lawsuits. Many observers wondered if mold would become the next big industry issue and be
\nthe subject of an
\nincreasing number of lawsuits and other litigation. It is important to remain vigilant about the risks of mold growth. When mold problems arise in the field, the issues
\nrelating to them generally
\nbecome the responsibility of the Design Engineer or the Installation Contractor. Correcting a mold problem can cost thousands, if not millions, of dollars. When mold is
\nfound in the walls of a
\nmulti-story condo complex because the insulation on the cold water lines did not perform properly, the cost to repair the damage can be particularly high. If mold is found
\nin the duct system of a
\nnew elementary school, the cost of remediation can also be very high, but can reduce health risks to the occupants. These real world examples should make every Design
\nEngineer,
\nMechanical Contractor, and Insulation Contractor take the issue of mold very seriously.<\/p>\n
To eliminate mold, it is crucial to understand the key environmental elements required for it to form. For mold to form and thrive, 3 conditions must be present: an
\nenvironment with an
\nair temperature within a range typically found in building interiors, the presence of a food source, and the presence of either sustained high humidity or water. The best
\nway to
\nattack mold is to eliminate 1 or more of the 3 conditions necessary for its growth. Elimination of the air temperature conditions is usually not an option. Eliminating the
\nfood source can
\nbe difficult, but should be considered. The food source does not have to be the insulation itself, which is often blamed. Rather, it can be the dirt or dust attached to the
\ninsulation, which
\nis almost always present. One option for reducing the propensity of the insulation to attract or capture dirt or dust is to use a jacket or select an insulation material
\nthat resists dirt
\naccumulation. However, use of a jacket in a duct liner application is usually not a viable option, so it can be difficult to completely eliminate the dust or dirt that
\nserves as a food
\nsource in those applications. Another option is the installation of UV lights inside ducts to eliminate mold—though this merely treats the mold rather than
\neliminating the source.<\/p>\n
The most common and tenable option for eliminating mold growth is to reduce moisture. Moisture can exist as either high humidity conditions or as water. Systems that
\noperate at below-ambient
\ntemperatures have the potential for surface condensation, making them susceptible to mold growth. The use of biocides can be used as a secondary deterrent, but eliminating
\nthe moisture
\nrequired for mold growth is the best option. There are several steps that can be taken to eliminate the presence of moisture, which can prevent mold from becoming an issue.
\nThree key steps are
\n1) specifying an adequate insulation thickness to prevent surface condensation; 2) selecting insulation materials that do not provide a food source for mold; and 3)
\ninstalling the
\ninsulation correctly and maintaining the insulation system.<\/p>\n
Step 1: Specifying Proper Insulation Thickness<\/strong><\/p>\n In a below-ambient system, the first step in preventing mold is specifying a thickness of insulation that will prevent surface condensation most of the time. When Step 2: Selecting Mold-Resistant Insulation<\/strong><\/p>\n Unfortunately, surface condensation cannot be totally eliminated from ever occurring for most systems. Some condensation will probably occur in the rare situations when Selecting an insulation that is resistant to mold growth is the second step in preventing mold and reducing the issues casual condensation creates. Insulations with a There are several test methods used to determine if an insulation or jacket material is “mold resistant.” In all cases, the test methods use clean, dry insulation or Step 3: Properly Installing and Maintaining the Insulation<\/strong><\/p>\n Installing the insulation and establishing a proper maintenance plan is the third step in preventing mold in a below-ambient system. The insulation materials being Following the aforementioned steps and making everyone working on the project aware of mold as a potential problem can often prevent it from occurring. The key to Below-ambient systems create unique environments that have the potential for a multitude of issues, one of which is mold growth. Mold growth can occur either on or in mechanical insulation on pipes and tanks if the right conditions are present. When mold grows inside duct work, it can be a very significant issue, and cause<\/p>\n","protected":false},"author":[184],"featured_media":0,"template":"","categories":[38,23,301,32],"class_list":["post-6845","articles","type-articles","status-publish","hentry","category-material-selection","category-condensation-control","category-design","category-health-and-safety","author-steve-fisher"],"acf":[],"yoast_head":"\n
\ndetermining this, it is
\nimportant to remember that codes or other minimal specified levels of insulation—even for below-ambient lines—are generally developed for thermal efficiency,
\nnot condensation control.
\nPreventing surface condensation sometimes requires greater thicknesses than those specified just for energy conservation (i.e., usually based on an economic thickness). To
\ndetermine design
\nconditions for unconditioned spaces (i.e., those spaces that are not continuously controlled for air temperature and percent relative humidity), it is recommended that the
\ndesigner follows the guidelines given in industry resources such as the ASHRAE 2013 Handbook of Fundamentals, Chapter 23, and the Mechanical Insulation Design Guide.<\/p>\n
\nthe environmental
\nconditions exceed the design conditions for which the insulation thickness was specified, particularly in unconditioned spaces. Selecting a jacket for the insulation and
\nspecifying an insulation
\nthat inherently resists moisture penetration will reduce the probability of condensation. Using a jacket that incorporates a metal foil in its construction, does not have
\nexposed
\npaper on its outer surface, and is sealed tightly at the joints is a good first step.<\/p>\n
\nclosed-cell structure—such as elastomeric, polyethylene, polystyrene, or cellular glass—are resistant to moisture penetration and have a history of resisting
\nmoisture without the need for an additional jacket. Other insulation materials work well with the proper design, vapor barriers, or jacketing. The best insulation to use in
\na specific application (i.e. cold water, chilled
\nwater, refrigeration, duct liner, etc.) depends on the temperature, configuration\/shape, and specific requirements of the application. Some insulation materials have a
\nbiocide incorporated in them for added mold resistance. The biocide should be approved by the U.S. Environmental Protection Agency (EPA) for use in ducts (air stream).<\/p>\n
\njacket samples, which is
\nusually not comparable to real world conditions where dirt\/dust is nearly always present as a food source. An insulation material’s testing and certification that it is
\n“mold resistant,” even when tested in accordance with a specific ASTM mold-resistant method, does not guarantee a mold-free installation if other factors are ignored. These
\nvarious tests and mold-resistant certifications may be useful, however, when comparing different insulation materials—while insulation cannot be guaranteed to be mold
\nfree, some materials may fare better than others. When comparing
\ninsulation materials, the same exact test method should be used for the basis of comparison. There are several third-party laboratories that certify products as being mold
\nresistant and are often
\ncited on insulation material product data sheets.<\/p>\n
\ninstalled should be dry,
\nand should have never been exposed to water. The building should be enclosed (i.e., not exposed to the elements), which limits the potential for the insulation being
\nexposed to water once
\nit is installed. In addition, when installing insulation on an HVAC system, the system should not be running and the piping and ducts should be dry. While installing the
\ninsulation, it is
\nmandatory for the installer to maintain the integrity of the insulation system for proper performance. Sealing all seams (butt, longitudinal, and termination points) is
\nmandatory for
\nbelow-ambient applications. Some insulation materials, such as flexible elastomeric and polyolefin, may use a contact adhesive rather than a tape to seal the seams. If the
\ninsulation
\nbecomes damaged (tears, holes, cuts, etc.), it must be repaired in a timely manner. Damaged insulation can lead to the degradation of the insulation on the whole system. It
\nis ideal, and less
\ncostly, to both design the application properly and install it according to the manufacturer’s instructions than it is to make the repairs after it is installed.<\/p>\n
\npreventing mold
\ngrowth is simple: keep it clean and dry. Effective condensation control to eliminate the presence of water is not a matter of chance, compromise, or cost minimization. From
\nthe beginning of the
\nproject, it requires clear communication among all parties involved and clear instructions on what is expected of them. While some condensation may occur when environmental
\nconditions exceed the
\ndesign conditions for which the insulation is specified, it is possible—with proper planning, materials, and maintenance—to materially lessen the chance of
\ncondensation and the
\nconditions that may lead to mold growth.<\/p>\n","protected":false},"excerpt":{"rendered":"