RENTERS BEWARE: APARTMENT HVAC CLOSETS CAN BE SOURCES OF MOLD AND DEGRADED IAQ

Furnace on water damaged OSB platform.  The return plenum is located beneath the platform.

Furnace on water damaged OSB platform. The return plenum is located beneath the platform.

A common practice in multi-story apartment and condominium complexes is to house the furnaces in closets that are located on the patio or balcony for each unit. The closets are aligned vertically in each building. Although the orientation is convenient for plumbing access, numerous water damage issues are inherent to this type of HVAC set-up.
Water damage from plugged condensate drain tubes or malfunctioning condensate drain pans is common. Slimy biological growth in PVC tubing and drain pans pan causes overflows. Current or historical overflows from the pans will appear on the sheet metal plenum under the A-coil. Drips and mold growth from malfunctioning units above a closet are commonly apparent as drip stains or growth on the ceiling and walls of the closet.
Water damage caused by freezing and thawing of the AC coils is common in apartment HVAC systems. Filter changes are often left in the hands of uninformed tenants. Plugged filters prevent sufficient air flow to the coil, causing it to freeze. As the coil warms up, the ice thaws, releasing large amounts of water into the return plenum, floor system of the apartment, furnace platform, or furnace closet below the damaged unit.
Another issue associated with stacked HVAC closets is the installation of the furnace on a platform, which is commonly constructed from plywood, drywall, or oriented strand board. When wet, all of these materials support the growth of mold and bacteria, which can produce various toxins. Additionally, the glues and resins in these materials can be liberated when wet.

Ceiling of furnace closet showing water entered from HVAC  closet above.

Ceiling of furnace closet showing water entered from HVAC closet above.

The return plenum in furnace closet systems is located beneath the platform, with the underside of the platform being the top of the plenum, a concrete slab serving as the bottom, and the walls of the platform forming the sides of the plenum. In addition to being difficult to clean, a water damaged common plenum provides both a contaminant source and transport pathway.  Dust mites, insects and their fecal material, garbage, cigarette butts, contaminated chunks of paper, and rodent feces are just a few of the treasures that have been recovered from plenums under furnace platforms.
When damage does occur, the underlying cause of water must be corrected. This involves replacing plugged drain tubing, cleaning drip pans, cleaning coils, and changing filters. For consistency, preventive measures in the form of routine inspections and HVAC maintenance should be the responsibility of the management company or maintenance staff.
Addressing the consequences of the water damage, whether it manifests as biological growth or deteriorated building materials, is imperative to appropriate HVAC hygiene and good indoor air quality. Contaminants on water damaged plywood, OSB, and drywall in the furnace closet and on the furnace platform can cause adverse health effects, whether the growth is active or historical. Once dried, mold and bacteria engage in survival mechanisms that can include toxin production and increased sporulation. When dry, the contaminants are easily liberated into the airstream.  Mold remediation is required when building materials in furnace closets become contaminated. The remediation involves two components (1) removal of the mold or contaminated building material and (2) addressing spores that are released from areas of actual growth. Engineering controls, containment barriers, HEPA filtered air filtration devices, personal protective equipment, HEPA vacuuming, and damp-wiping are all essential for safe and effective remediation in water damaged furnace closets.

Return grille located inside of the apartment behind the furnace platform.  Stains show repeated wetting fo tack strip.

Return grille located inside of the apartment behind the furnace platform. Stains show repeated wetting fo tack strip.

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MOLD TEST KITS: Why You Should Not Do-It-Yourself

Using a “do-it-yourself” (DIY) mold test kit to evaluate whether a home has a mold problem makes about as much sense as replacing an annual doctor exam with using a thermometer to take your temperature.  Just as a person could be very ill while maintaining a normal temperature, a home could have a serious mold problem, even though a DIY test was negative.

Designing, executing, and understanding a comprehensive indoor mold assessment is difficult enough for professional mold consultants.  The best ones understand that building dynamics, hidden mold, historical damage, sampling techniques, analytical methods, and many other factors can influence the accuracy and effectiveness of diagnosing indoor mold problems.

Unlike chemical testing, no dose response curves have been developed for mold exposure.  Therefore, sample results will often raise more questions than answers.  Mold spores are always present in indoor environments. They enter buildings through doors and windows, and usually are not a problem unless they have suitable nutrients for growth.  All building materials can support mold growth IF sufficient moisture is present.  Moisture can come from leaks, floods, or excess humidity.

When sufficient moisture is present, certain molds that are usually minor constituents of outdoor air grow disproportionately to predominant outdoor molds that grow on decayed vegetation.  The molds that grow indoors on wet drywall, wood, and other cellulose materials are most frequently in the genera, Aspergillus, Penicillium, Stachybotrys, and Chaetomium.  These molds can present health problems when they grow indoors.  In addition to allergic reactions, triggering of asthma, and infections, many molds that grow indoors produce secondary metabolites, such as toxins.   The tightness of indoor environments can promote exposures and adverse health to occupants of water damaged buildings.

The single best tool in a mold assessment, whether it is performed by a professional or a do-it-yourselfer, is a detailed visual inspection.  The simplest inspection involves observations of mold growth after a water damage event.  If you see it, yes it is there, and must be addressed to prevent air quality problems.  More involved inspection that require professionals are those in which prior unmitigated water damage has been concealed or construction defects result in hidden water damage in ceiling, wall, or floor cavities.

For the do-it-yourself mold tester, the best that can be expected from a home test kit is to identify the type of mold is visibly growing on a surface.  However, if it is growing, the source of moisture must be corrected and the mold must be removed under controlled conditions.  Since remediation procedures are not dictated by the type of, testing is usually a waste of money.  If the area of growth is small and a low likelihood exists for hidden mold, addressing the mold according to EPA guidelines found in A Brief Guide to Moisture, Mold and Your Home (epa.gov) is sufficient.  If the mold covers a large area or hidden mold is suspected, a professional remediator is usually required to avoid hazardous exposures and cross-contamination to unaffected areas.

The worst outcome from a do-it-yourself mold test kit is that negative results will give a false sense of security when in fact hidden mold problems do exist.   False negative are common in culture plate kits (petri dishes) that instruct the user to place the open plate in a room for a specified period of time to collect mold that settles from the air.  The lab reports for settling plates might list several types of mold that grew the petri dish.  However, the data is usually inconclusive at best.  One problem with “settling plate” is that all molds do not settle at the ratio in which they are found in the air.  Therefore, many species can go undetected.  Another issue is that the actual concentrations of mold spores per volume of air cannot be calculated because the sampling method cannot quantify the amount of air to which the culture plate is exposed.  Additionally, the methodology does not address whether the molds entered from outdoors or were from areas of actual indoor mold sources.

Another type of test that might be recommended for the culture plates is to tape the open culture plate to a supply register to allow the air from an operating HVAC system to impact the plate for a specified time.  Unfortunately air exiting from the airducts does not necessarily represent air within the home because the air that passes through a filter before impacting the culture plate.  Additionally, the likelihood that contaminants would actually be released from an area of growth, enter the air stream, be sucked into the return ducts, pass through the filter, and ultimately end up on the culture plate is very low. 

Swab type test kits are commonly available for DIYers.  Directions generally instruct the user to wipe the swab over a small area (usually 1 sq. inch) of suspect mold growth.   The resultant lab report might list several molds that were found in the swab sample, but this method cannot differentiate between settled spores and what might have actually been growing on the surface.   In either case, the results should not be mistaken to represent the moldiness of the whole house.

Still another type of surface sample that can be found in home mold test kits is a tape lift sample, which involves using clear cellophane tape to “lift” suspect mold from a surface.  This type of sample can be useful in identifying not only the type of mold that is present on a surface, but can also differentiate between actual mold growth and spores that settled from the air.   But the sample would be representative of the tested area only and would not provide information on the overall mold conditions in the indoor environment.

Mold testing can be a useful tool in the hands of a knowledgeable investigator that designs a sampling plan to address a question that cannot otherwise be answered.  Unfortunately, even within the mold assessment and remediation industries, few investigators understand the principles of microbiology, building science, engineering, and scientific methods that are required to conduct a meaningful mold investigation.  With so many variables and limitations in mold testing and analytical methods, “do-it-yourself” mold test kits are generally a waste of time and money.

DAMMED ICE: MARCH IS TIME TO CHECK THE ATTIC FOR MOLD AND WATER DAMAGE

Dammed Ice

In winter months, they can be spotted throughout the northern regions of the United States.  At first they might seem harmless.  Some even sparkle as the winter sun reflects from the stalactite-like structures.  They are ice dams, and these giant icicles are surefire predictors of damned indoor air quality.

Ice dams are caused when the temperature on the upper part of a roof is warmer than on the lower edges.   The melting snow freezes at the colder lower edges, creating dams in the eaves troughs (gutters).  Problems start when the dammed ice begins to melt, and water backs up under shingles, seeking the paths of least resistance.

Water that backs up under shingles and runs into the attic, insulation, walls, and ceilings often remains undetected.  However, hidden within the wet cavities are feeding frenzies for mold and other nasty microorganisms.  Sustained  moisture causes structural damage, odors, and biological growth.       

Consequences of Dammed Ice  In most regions of the US, ice dams melt before March, and signs of  water damage begin to appear.  Some indicators of water damage from ice damming include:

•             Curling and cupping of shingles

•             Stains on ceilings and walls

•             Stains on the underside of a roof deck

•             Mold growth on wood structures in the attic

Drip stains on the topside of insulation and drywall ceiling

•             Drip stains on insulation in the attic

•             Oxidized nails on the underside of a roof deck

•             Musty or mold type odors

 If signs of damage from ice damming are discovered, a qualified professional should be called upon to evaluate structural damage, assess mold growth,  and develop a safe remediation plan.   A qualified consultant will not only provide recommendations for addressing visible mold and water damage, but will also identify areas that should be evaluated for hidden damage. To prevent cross-contamination during invasive investigations into suspect cavities, personal protection, HEPA-filtration, and partition barriers should be used.   An ounce of prevention is priceless when hidden mold contamination is found, especially in a home with immune compromised individuals.

  Remediation

Effective remediation involves two components: (1) removal of the mold and (2) addressing spores in the air and on surfaces.  Removal of attic mold caused by ice damming typically requires removal of the affected roof decking, as the growth is not limited to visible surfaces.  Trusses, joists, and other wood roof members can usually be cleaned using some type of abrasive cleaning.  One of the best abrasive cleaning methods for attics is dry ice blasting.  This method is not only less labor intensive than sanding or scrubbing, it is more effective because the dry ice freezes the surface of the moldy substrate.  Dry ice blasting also facilitates cleaning of crevices and hard to reach areas.  As with all mold remediation, appropriate containment measures, personal protection, and engineering controls must be employed.

  Remediation after ice damming generally requires removal of the attic insulation.  Insulation that is directly impacted by water loses its efficiency.   Insulation in proximityof mold growth must be removed because of cross-contamination.  Aerosolizing of mold spores, fragments and other propagules that settle onto insulation can cause adverse health effects.  After insulation is removed from an attic, surfaces must be cleaned to remove particulate debris and settled spores.

Removal of attic insulation also allows for a thorough inspection of the topsides of drywall ceilings.  Assessment of staining patterns can provide clues about areas of potential hidden water intrusion into wall cavities.  Drywall with visible mold growth on the topside of ceilings must be removed under appropriate containment.

 Appropriate mold remediation after ice damming is necessary to protect the air quality within an indoor environment and prevent structural damage.  Re-construction after remediation must be executed in a manner to correct the conditions that caused ice damming in the first place.  The most common approaches to preventing dammed ice involve installation of appropriate insulation, ventilation and vapor barriers.  Roofing contractors should provide warranties and be held accountable for these issues.

Mold and ice crystals on the underside of a roof deck

From Our Video Archives: Sanit-Air Featured On PBS “The Business Page” Television Program

The nationally recognized Public Broadcasting System affiliate in Detroit, WTVS Channel 56, produced and aired a wonderful local business program titled “The Business Page.” Sanit-Air and our team of environmental IAQ experts and technicians had the distinct pleasure of an extensive feature on “The Business Page.”

Producer Mike Echols narrates this business feature that serves as a nice introduction to the basic understanding of the workings of Sanit-Air and the foundation for our CleaniNEST™ brand and consumer crusade. We hope you find “The Business Page” feature on Sanit-Air informative.

Sanit Air & CleanliNEST™ Featured in Today’s C & G News

Connie Morbach Suited Up Examining Mold

That's me all suited up and taking mold samples...

We’re excited to announce we were featured in today’s C&G News in an insightful feature written by the C and G’s Christa Buchanan. Click on the link to read and learn more: http://www.candgnews.com/Homepage-Articles/2010/06-23-2010/Indoor-contaminants.asp

Crawlspaces & Ventilation: 10 Fun Facts & Random Observations

1. Inside the living space of a property, proper ventilation is absolutely crucial to the health, safety, and overall comfort of the occupants inside the home.

2.  Standards and guidelines have been established to specify minimum ventilation rates and other measures intended to provide indoor air quality that is acceptable to human occupants and that minimizes adverse health effects. More info here:  http://eetd.lbl.gov/ie/viaq/v_rates_1.html

3.  Improving the overall air quality inside a property can be achieved by two methods:

•    Exhausting air contaminants from the building
•    Removing contaminants from the air stream using filtration and/or absorption technologies (i.e. HEPA filtration and activated carbon)

Since most residential properties do not have access to proper filtration or absorption technologies, exhaust ventilation is most practical and commonly used.

4. In addition to improper ventilation, excessive or chronic water intrusion into the property, especially the crawlspace, will contribute to the growth of certain microorganisms.  This can lead to mold infestation impacting Indoor Air Quality, and even more destructive structural damage such as wood decay or dry rot.

5. Water intrusion into the crawlspace will often cause damage to flooring systems (i.e. cupping of hardwood floors, grout separation in tile floors, etc.), wood decay, and oxidation or rusting of metal strapping/hardware.

6. Water enters a crawlspace in either liquid or vapor phase by four moisture transfer mechanisms:

•    Liquid water (i.e. plumbing/sewer leaks, high groundwater table, drainage or exterior flooding)
•    Capillary suction or wicking (i.e. moisture being drawn through concrete footing from saturated exterior soils)
•    High moisture laden air (i.e. elevated humidity from atmospheric conditions entering the crawlspace through vents)
•    Vapor diffusion (i.e. moisture in the vapor phase moving through building materials)

7. Most properties are constructed with vents that are intended to remove moisture from the air in a crawlspace by cross-ventilation.   However, the introduction of moist air from outdoors can actually increase the relative humidity in a crawlspace.

8. Due to stack effect and vapor diffusion, which is a very powerful force, moisture in a crawlspace will seek dry areas.  When moist air comes in contact with  a surface that is colder than the  air, condensation will occur.  Condensation can develop on uninsulated plumbing pipes in the crawlspace, on the underside of a sub-floor, or even the attic roof deck.  Interestingly, many houses with exposed wet soil in a crawlspace also have mold and water damage due to condensation on the underside of the roof deck. 

9. If vapor diffusion from the soil, water intrusion from poor drainage, unmitigated plumbing leaks, or infiltration of moist air exist in a crawlspace, one or more of the following is usually observed:

  •   Surface mold growth, structural damage, and health issues
  •   Termite or other pest infiltration
  •   Accumulation of odors  
  •   Termite or other pest infestation

10.  The best way to mitigate crawlspace moisture is to treat the crawlspace as a conditioned space by (1) insulating walls with foam panels, (2) seal the crawlspace floor and walls with heavy gauge polyethylene or vinyl encapsulation system, with the seams sealed tightly at all edges and overlaps, (3) seal the rim joists with two-part closed cell foam.

Good Morning America & CleanliNEST™ by Sanit-Air Team Up For Investigative Report

We’re excited to announce that ABC’s Good Morning America will be in town tomorrow, Wednesday April 28, 2010 to film an investigative report for which the CleanliNEST™ by Sanit-Air team will be lending our expertise. The samples have been submitted to the lab and GMA will be here to film my response, as well as the sampling procedure and analysis in our CleanliNEST™ by Sanit-Air lab.

We can’t reveal at this time the topic as it is an investigative report. We can say, however, it will be eye-opening, enlightening, informative and of particular interest to women. We’ll give everyone the heads-up when the segment will air on GMA so stay tuned!

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