Category A Healthy. House

Throughout most of the country, forced air is the most common form of heating and cool­ing in new construction. Besides quick re­sponse time, the main advantage of forced – air heating lies in the opportunity it gives the homeowner to commission modifications and additions to standard equipment to cre­ate a healthy air-distribution system. A modi­fied system can control humidity, filter air, and introduce fresh, conditioned air from the out­side. Disadvantages of a forced-air system may include greater operating costs, noisy opera­tion, larger space requirements for equipment installation and ductwork housing, deple­tion of negative ions, and the need for regular maintenance and cleaning of ductwork to pre­vent mold and dirt buildup.

Disadvantages of a standard forced-air system can also include distribution of odors and particulate matter, and unwanted dehu­midification. Forced-air heating, which heats air, is considered to be far less comfortable than radiant heating, which heats objects. A forced-air system must be properly designed for appropriate balancing and distribution. Poor indoor air quality, energy inefficiency, and discomfort can result when system design is inadequate.

If forced air is your choice for heating and cooling (in much of the country this may be the only cost-effective choice), you can take advantage of the whole-house air distribution ducting that will already be in place to improve air quality by implementing the steps below:

• Use a fresh-air intake vent from the outside to the furnace to introduce and distrib­ute fresh, tempered ventilation into your home. Locate the vent so that it receives “fresh” air; do not place the vent near trash storage areas or where auto exhaust and other pollutants could be brought inside the house.

• Install enhanced filtration in your forced – air stream. (See the Air Filtration section below.)

• Choose a furnace with sealed combustion to avoid the entry of combustion byprod­ucts into the airstream.

Design of Healthier Forced-Air Ductwork

Care must be taken during the design, instal­lation, and maintenance of forced-air duct­work because the means of air distribution is often the source of allergies and other health problems associated with forced-air heating and cooling.

Ductless air plenums are a common source of air contamination associated with HVAC systems. Joisted floors, and wall cavi­ties without ductwork, act as pathways for contaminated attic or crawl space air to en­ter the building if air is forced through them. Fibers from wall and ceiling insulation are frequently sucked into the return side of the heating system and circulated throughout the building envelope. Furthermore, the plenums are inaccessible for cleaning and impossible to seal.

Floor registers should be avoided because debris will inevitably accumulate in them, not only during construction but also in the course of occupancy. For this reason, supply and return registers should ideally be located on walls or ceilings. Below-slab ductwork should be avoided because it can collect mois­ture and dirt, providing a breeding ground for microbes. Also avoid running ductwork through uninsulated spaces if at all possible. If this is unavoidable, the ductwork should be well insulated on its exterior.

Ductwork should be easily accessible for future inspection and maintenance. A good design should specify cleaning portals that will give access to all ductwork, especially points of probable condensation. Sheet metal is preferable to plastic flex ducts because the flex ducts are difficult to keep clean and are easily damaged. Ductwork may be coated with undesirable oils from the manufacturing process and should be cleaned of all oil prior to installation.

Installation of Forced-Air Ductwork Quality control during the installation of a well-designed ductwork system will help en­sure optimum efficiency and health. Ductwork should be well sealed with a nontoxic sealer. Ideally, an air distribution system should have a neutral effect on building pressurization.

A large amount of dust and debris is gen­erated during the construction process, and it frequently finds its way into the ductwork, becoming a source of air contamination once the system is in operation unless measures are

taken during construction to keep the duct­work clean.

In order to achieve an optimal ductwork system installation, we suggest the following specifications:

• Metal ductwork shall be free of all oil resi­dues prior to installation.

• Ductwork shall be well sealed with non­toxic compounds such as AFM Safecoat DynoFlex, RCD6, Uni-Flex Duct Sealer, Uni-Mastic 181 Duct Sealer, United Duct Sealer (Water Based), or approved equal. Mastics shall be water resistant and water-based, with a flame spread rating no higher than 25 and a maximum smoke developed rating of 50.

• During construction, the ends of any par­tially installed ductwork shall be sealed with plastic and duct tape to avoid the

introduction of dust and debris from con­struction.

• All forced air must be ducted. The use of unducted plenum space for the transport of supply or conditioned air is prohibited.

• Cloth duct tape shall not be used. (It has a high failure rate that can result in unde­tected leakage.)

• All joints, including premanufactured joints and longitudinal seams, shall be sealed.

• Gaps greater than Vs inch shall be rein­forced with fiber mesh.

• All ductwork running through uninsu­lated spaces shall be insulated to a mini­mum of R-io to prevent condensation problems and to save energy.

• Any ductwork requiring insulation shall have the insulation located on the outside of the ducts.

• Ductwork must be professionally cleaned prior to occupancy. The duct-cleaning

A retired couple contacted John Banta because they were experiencing eye irritation and diffi­culty breathing caused by dust in their home. In spite of frequent vacuuming and dusting, an un­usually heavy deposit of dust was noted on the furnishings during the house inspection. John suspected that the furnace system was the source of contamination because the heat registers in the home were lined with a fine dust and the clients’ symptoms worsened when the furnace was on.

John was puzzled, though, by the lack of dirt on the cold air return filter and the absence of air movement. He opened the cold air return and ex­amined the inside wall to see if there were any vis­ible obstructions. To his surprise, he found no duct at all. The cold air return was a dummy and went nowhere.

Further investigation revealed that the fur­nace and duct system were located in the crawl space under the home. John inspected the crawl space, where he discovered that there was no con­nection between the cold air return port on the furnace and the rest of the house. In fact, the fur­nace was taking cold air from the crawl space and blowing the unfiltered, contaminated air directly

can influence the ultimate outcome. For this reason we have provided specifications for the contractor where relevant. Finally, a regular cleaning and maintenance program is essen­tial for optimal efficiency. This task will ulti­mately fall to the owner and may influence your choice of HVAC system.

Choice of Fuel Source

Gas and other sources of combustion fuels can pollute the airstream if you do not plan care – into the house. Consultation with a heating and air conditioning company was recommended to cor­rect this construction defect.

Discussion

HVAC duct systems should always be leak-tested to ensure that they meet specified standards. The stated industry standard for a sealed duct sys­tem is less than 3 percent leakage, which is rarely achieved. The furnace itself will account for much of the leakage since it is difficult to seal. The fur­nace should be mounted in a clean, easily acces­sible area such as a mechanical room and not in an attic or crawl space.

Leakage also occurs at unsealed joints where the metal ducts fit together. Since the return side of the furnace is sucking air back into the furnace, it will suck contaminants through leaks in the duct­work. If the unsealed ducts pass through walls or attics containing fiberglass, fiberglass particles are sucked into the ducts and blown into the house. If the unsealed ducts are in a crawl space under the home, then moldy, pesticide-laden or dusty air can be sucked into the furnace system and blown into the house.

fully. Electric heat is often considered “cleaner” heat because combustion does not occur in the home. However, environmental pollution from electricity generation plants must be ac­knowledged. Moreover, electric heating ap­pliances generate electromagnetic fields, an invisible and often overlooked source of pol­lution. Whatever your choice of fuel source, there are several strategies that can be em­ployed in the mechanical room that will make heating healthier.

Mechanical Room Design

• The mechanical room should be a dedi­cated room, insulated and isolated from the living space either in a separate build­ing or in a well-sealed room that ventilates to the outside. It should be easily accessible for regular routine maintenance.

• The equipment in the mechanical room may produce elevated levels of electro­magnetic fields and should not be located adjacent to heavily occupied living spaces.

• Ensure the supply of adequate combustion air to the mechanical room.

• We recommend that you locate a fire alarm in the mechanical room.

• If there is a water source in the mechanical room, there should also be a floor drain.

Heating and Cooling Appliances

We recommend the following guidelines for choosing, locating, and maintaining heating equipment:

• Purchase equipment designed for back – draft prevention.

• Use sealed combustion units to prevent transfer of combustion byproducts into the airstream. This is especially important where the mechanical room must be ac­cessed directly from the living space.

• If you are using a forced-air system, we strongly recommend adding a good com­bination filtration system that will filter out both particulate matter and gas.

• If possible, choose a heating system that does not run hot enough to fry dust. Hy – dronic systems and heat pumps meet this requirement.

• Institute a regular maintenance program to clean components, change filters, and purge mold or mildew growth.

Hydronic Heating

Hydronic heating, delivered through hot wa­ter, is usually a wall-mounted baseboard or radiant floor system. Baseboard systems are usually made of copper tubes and aluminum radiating fins with painted steel covers. Base­board radiators can be noisy if not maintained, and they can become traps for dust and dirt. Some baseboard units are subject to outgas – sing at first, when the factory-applied paint on them gets hot. Verify with the manufacturer if this will be a problem with the model you are considering.

Hydronic radiant floor systems are usu­ally made of plastic, rubber, or copper tubing installed within or under the floor. Hot water circulating through the tubing heats the floor mass and the heat then rises through gentle convection. Radiant systems are silent and clean. Because this form of heating heats feet, occupants are comfortable at lower operat­ing temperatures. The water running through the piping is not hot enough to fry dust. Note that hydronic radiant floor heating should not be confused with radiant electric heating, in which the heat source is heated electrical wir­ing. We do not recommend this type of heat­ing because it will distribute a magnetic field throughout the home when in operation.

At one time, radiant floor heating used copper tubing almost exclusively but the ris­ing price of copper, combined with the intro­duction of plastic and rubber tubing, made this a less common option. Metal tubing, such as copper, can conduct electromagnetic fields through the structure if it becomes charged at any point along its route and for this reason we do not recommend it. Some in-floor systems use very odorous rubber products. While this is not a problem where they are embedded in concrete, it can be a source of indoor pollution where the tubing is exposed at access points. Wirsbo Hepex, a crosslinked polyethylene tubing, or Kitec, a crosslinked polyethylene tubing with an aluminum core, are odorless products for radiant floor heating.

The advantages of a hydronic system in­clude slightly lower operating costs, even heating, quieter operation, ease of zoning, and independent room-temperature control. Disadvantages of the hydronic system include slow response time and higher installation costs compared to forced air because of the number of mechanical components.

Methods of heating, cooling, and ventilating homes have many important health ramifi­cations that will affect us long after the initial building materials have outgassed and reached a neutral state. If we lived in a pristine natu­ral environment with low humidity and mild temperatures, we would be able to condition our homes without mechanical assistance by means of solar gain, shading, and cross­ventilation. Residents throughout most of North America do not have this luxury. Cold and cloudy winters, hot and humid summers, and polluted or pollen-filled air are realities from which homes must shelter occupants.

We have come to expect a level of comfort and temperature control in our homes un­dreamed of by our not-too-distant ancestors. Along with the increased comfort level, we have unwittingly come to accept many health problems associated with heating and cooling

systems. In fact, more than any other build­ing system or component, heating and cooling methods can be a major cause of sick building syndrome. Some of the problems include:

• toxic fumes from gas, oil, or propane fuels that work their way into the building enve­lope through leaky supply lines, from in­sufficiently ventilated or improperly sealed mechanical rooms, and from open com­bustion appliances

• backdrafting of hazardous and sometimes deadly gases into the living space from flues

• infiltration of pollutants from outside the building envelope resulting from depres­surization

• fried dust resulting from hot surface tem­peratures on heating appliances

• circulation of dust through an unfiltered forced-air heating system

• contamination from mold growing in the ductwork and air conditioning equipment

• fiberglass fibers from ductwork insulation that circulate in the living space

In the following section we focus on ways of reducing the need for mechanical heating and cooling. Later in this chapter we present guidelines for healthier heating and cooling installations, language for specifications, and maintenance suggestions that will help elimi­nate some of the problems mentioned above.

Reducing Heating and Cooling Loads Through Design Strategies

The application of a few simple design and planning principles can greatly reduce the amount of mechanical heating and cooling required to live comfortably, thereby improv­ing health and lowering energy consumption. In designing your home for energy efficiency, consider the following suggestions.

Create an Energy-Efficient Building Envelope

• Choose an exterior wall system with a high insulation value.

• Choose interior wall and floor systems with high levels of thermal mass to assist in

keeping things cool in summer and retain­ing heat in winter.

• Seal cracks and joints to prevent unwanted infiltration and exfiltration.

• Choose a high insulation value for the ceil­ing. This measure will be especially cost ef­fective because most heat escapes through the roof.

Consider the Surrounding Site as an Extension of Your Climate-Control Design

• Make use of deciduous trees to shade in summer and allow solar gain in winter.

• Observe prevailing wind patterns when planning for natural ventilation.

• Consider using trees as windbreaks to lower the heating load created by cold win­ter winds.

• Situate your home as far away from pollu­tion sources as possible so that the site can provide a quality air supply for home ven­tilation.

Take Advantage of Solar Heat

• Orient the home to take advantage of solar gain.

• Plan fenestration (arrangement of doors and windows) for the desired amount of heat gain.

• Make use of overhangs and sun angle in­formation to prevent overheating in sum­mer.

• Use light colors to reflect heat and dark colors to absorb and store heat.

• Provide thermal mass for heat storage.

• Provide cross-ventilation to facilitate nat-

ural air exchange and to provide cooling in summer.

• Use thermal window-shading devices to control heat loss.

• Use specialized window coatings to en­hance solar gain where desired and block unwanted heat gain.

Become a More Active Participant in Temperature Control

• Open and close windows to provide fresh air and control temperature.

• Open and close thermal shading devices to control heat gain and loss.

• Utilize automated thermostat controls to economize on heating and cooling when you are absent or asleep.

• Be willing to add and subtract layers of
clothing to allow for a greater range of ac­ceptable temperatures.

• Consciously acclimatize your body to a broader comfort range.

Healthier Heating and Cooling

Each heating and cooling system has advan­tages and disadvantages that you must weigh carefully when choosing a system that best fits your needs and budget. Once you have made a choice, there are several design, construction, and maintenance considerations that will op­timize performance and minimize the health risks of the system. In the preliminary design phase, you and your architect must consider factors such as the location of the mechani­cal room. During the construction phase, the choice of materials and installation procedures

CASE STUDY 15.1

Water Supply and Waste

Polyvinyl chloride (PVC) is the standard for residential supply and waste piping. PVC plas­tic piping has been shown to outgas diethyl phthalate, trimethylhexane, aliphatic hydro­carbons, and other harmful gases. It should not be used for water supply piping in a healthy home. Because of the pollution resulting from both the manufacture and the disposal of PVC piping, we recommend seeking alternatives for waste lines as well.

Water Supply Pipe

Although we can choose the type of supply pipe we want in a new home, we have no con­trol over how water is delivered to our prop­ertyline. Well water is often delivered through PVC piping. Municipal water supply can be piped through a variety of unsavory piping, including PVC and asbestos cement. We rec­ommend whole house water purification at the point where water enters the house. In Division n we outlined several whole-house water purification strategies. From the point at which water is purified, it makes sense to distribute it in piping that will not have an adverse affect on water quality. Your specifi­cations could include one of the following ac­ceptable alternatives for supply piping:

• Type L or Type M copper: Solder shall be lead-free silver solder. The system shall be flushed prior to occupancy to eliminate any flux from the soldering operation.

• Wirsbo Aquapex: A crosslinked polyethy­lene that shall be installed by a certified installer.

Waste Drain System

Waste drain systems do not have the same wa­ter quality concerns as supply piping does and are almost always plastic because it is most economical. We prefer to specify ABS pip­ing because of the problems associated with the production and burning of PVC piping. Pipe assembly glues are highly volatile and

toxic and their use onsite should be carefully managed to reduce pollution. You may wish to specify the following:

• Assemble pipes with the longest pieces possible to minimize the amount of glue or solder required.

• When possible, glue waste pipe assembly outside the building envelope.

• Wipe up excessive glues and protect all surfaces from glue drips and spills.

• Whenever glue is being used inside the structure, provide adequate ventilation until all odors are dissipated.

Floor Drains

Appliances containing water, such as water heaters and washing machines, can malfunc­tion and leak. You can avoid the subsequent water damage and mold if you plan for this possibility If floor drains or drain pans are strategically located, the water from acciden­tal spills can be diverted to the sewer line or to the outdoors. Drains that lead to the sewer line should be installed with a trap to prevent un­wanted sewer gases from entering the home. It is important that the traps be “primed,” or kept filled with water, which creates a physical barrier against the entry of sewer gases. Self­priming drains can be installed so that the trap will remain filled with water without ad­ditional maintenance.

Plumbing Penetrations

Where plumbing penetrates walls and ceil­ings, the air space created around the open­ing must be completely sealed to prevent unwanted air infiltration. Consider specifying the following:

Wherever plumbing penetrates the wall, aquarium-grade 100 percent silicone caulk­ing shall be applied to create an airtight seal.

Backflow Protection

In some communities, sewage systems peri­odically back up and flow into homes, leading to devastating contamination. Backflow pre­vention devices installed on the home waste line will usually prevent this. The local plan­ning department may be able to help you de­termine if backflow prevention devices are advisable. In many communities, claims for sewage damage will not be paid unless such devices were in place prior to the incident.

A barrage of chemical odors often assaults new homeowners as they enter their newly constructed home. Many people who have never before been affected by chemical sensi­tivities find they are bothered or made chroni­cally ill by prolonged exposure to the fumes in their new home. Sniffing finishing materials such as upholstery, carpets, and paint before they are installed will reveal important infor­mation. However, even if a building product or material passes the sniff test when sampled, the odor can become unbearable once the product is installed because chemical fumes accumulate inside the house and are emitted from a much larger surface area than that of the sample.

If you are unsure how you will tolerate a product once it is applied or installed in your house, we recommend that you test the prod­uct before purchase in a manner that will sim­ulate the level of concentration in the home. One method is to place a sample of the prod­uct in question in a large glass jar with the top screwed on tightly to allow fumes to accumu­late. The following day, open the jar and sniff the contents for unacceptable fumes. If the sample is too large to be placed inside a con­tainer, keep it next to your pillow while you sleep. Pillow testing should be done only if you are reasonably sure you will not have a severe reaction with prolonged exposure.

For some products it is important that the samples be new. For example, a carpet swatch that has been in a showroom for three years will not provide an accurate indication of what a freshly unrolled carpet will smell like in your home. Samples of other products — such as wet-applied finishes like paints, seal­ers, and adhesives — should be applied to an inert surface such as glass or foil and then be allowed to air out in an uncontaminated lo­cation for a few weeks to better simulate the cured or semi-cured state that the product will be in on move-in day.

This type of testing, although somewhat helpful, has obvious limitations. While the test gives information about the product in ques­tion, it does not indicate cumulative effects or synergistic effects with other chemicals. Since you cannot predict these effects in advance, the goal is to choose products with the lowest levels of odor and toxic emissions.

Further Reading

Floor Seal Technology, Inc. Concrete Vapor Emis­sions and Alkalinity Control. Available from 800-572-2344, 800-295-0221.

Institute of Inspection, Cleaning and Restoration Certification. ANSI/IICRC S500-2006 Standard and Reference Guide for Professional Water Dam­age Restoration.^ ed., IICRC, 2006. Available from 2715 East Mill Plain Blvd., Vancouver WA 98661,800-835-4624,360-693-5675, iicrc. org.

Institute of Inspection, Cleaning and Restoration Certification. IICRC S520 Standard and Refer­ence Guide for Professional Mold Remediation. IICRC, 2003. Available from 2715 East Mill Plain Blvd., Vancouver WA 98661,800-835-4624, 360-693-5675, iicrc. org.

Chart 13.1: Test Kits and Equipment

Chart 13.1: Test Kits and Equipment (cont’d.)

Although do-it-yourself tests may indicate that a problem is present, consultation with a remediation specialist is often re­quired for accurate diagnosis and safe, effective remediation.

Conveying

Systems

This division is not used in most residential construction.

In Division 7 we discussed radon gas and miti­gation. There are several acceptable methods currently being used to measure radon in air and in water. Some test kits are available through local hardware stores (see Chart 13.1). It is important to follow the manufacturers in­structions precisely.

Radon Testing in an Existing Structure

The general procedure for radon air testing, regardless of the type of kit used, is:

• Close the home for a minimum of 12 hours before beginning the test and keep it closed throughout the testing period. You may enter and leave the house as long as the doors are not left open.

• Place the sampler about 30 inches above the floor and at least two feet away from the wall in the area being tested. Keep the sam­pler away from doors, windows, fireplaces, outside walls, corners, and any other places where drafts or stagnant air may exist. These precautions are necessary to ensure that the sampler is exposed to a representa­tive sample of air.

• Accurately record the starting and stop­ping time. This information, along with the date, must be included with the sam­ple when it is returned to the lab. Without precise recording information, the results cannot be considered valid.

A typical radon test kit costs less than $25. After each individual test, the kit must be re­turned to a laboratory for analysis. Multiple testing or continuous monitoring can be car­ried out with electronic radon monitors.

Radon Land Test

Radon mitigation is most effective and least costly when incorporated into the construc­tion of the home. If you are building a new home and there is reason to suspect a radon problem, a land test is advisable. Although the test will not provide a definitive answer as to what the radon levels will ultimately be in the finished home, it is nevertheless an indicator that will help you decide whether mitigation measures should be included in your con­struction plans.

The test kit available for measuring radon in the soil requires placing a special collection box with its open side over the soil to be tested. Mound soil around the lip of the box to form a tight seal and keep the box in place. Radon gas is trapped and concentrated in a carbon me­dium and can then be measured by a testing apparatus. Record the starting time and date. After the prescribed period of time (usually 48 hours), push the soil away, retrieve the tester, and return it to its foil pouch. Record the stop time and send it with the other information and materials to the lab for analysis.

Radon Water Testing

Radon found in water poses a health threat when released into the air and inhaled. Hot, steamy baths or showers with water that has high radon content can be a serious source of exposure. Since the EPA requires munici­pal water sources to screen for radon, it is nec­essary to test only well water. Small amounts of radon can be removed with special car­bon filters. A high radon content (5,000 pico – curies per liter or greater) is more difficult and costly to remove. (See Chart 13.1 for test kits for radon in water.)

Certain parts of the home, such as garages, at­tics, and crawl spaces, should be completely sealed from the rest of the house in order to prevent the passage of contaminated air into living spaces. One easy way to test for leaking airflow is to use a theatrical fog machine. This is the same equipment used onstage and in movies to create fog for special effects and can be rented from most theatrical supply com­panies. Place the unit in the area to be tested, turn it on to fill the space with fog, and then observe the adjoining areas for signs of fog that indicate where leaks must be sealed.

When testing the garage, seal the door and the open vents with tape and plastic to pre­vent the fog from escaping. The same can be done for attic and crawl-space vents and other
intentional openings to the outdoors. Com­mon air-infiltration points revealed by the fog test include electrical outlets, the junc­ture where the gypsum board meets the floor, and around poorly sealed plumbing, electri­cal, and ductwork penetrations. Theatrical fog testing is especially helpful when performed in conjunction with a blower door. This will al­low simulation of a variety of adverse weather conditions that may create unusual indoor air quality problems during inclement weather. Be sure to notify the fire department before you begin this type of test; otherwise a well­meaning neighbor who sees the smoke might dial 911 and set the fire trucks in motion.

Testing for Leakage in Air Distribution Systems A consultant can test for leakage in air distri­bution systems in a manner similar to blower door testing for a whole house. Doing this testing while the ductwork is still accessible, before it is covered with finishing materials, will simplify repairs. Supply and return regis­ters are sealed off so that the system can be de­pressurized using a blower door or calibrated fan. The combined airflow through all leak­age openings can then be determined. Ide­ally, leakage should be less than 3 percent. If a small amount of excess leakage is revealed, a theatrical fog machine can be used to trace the sources. If leakage is extensive, it will be neces­sary to examine all junctures and reseal where required prior to retesting.

Blower doors consist of a sophisticated fan set in an adjustable frame. They are used to test airflow and pressure in a home. There are many uses for blower doors, such as detection of leaks in walls and in heating, ventilation, and air conditioning (HVAC) system duct­work. You can also determine if the ventilation is adequate and identify the location of energy leaks in the structure.

Since the equipment requires extensive training to use, we recommend that you hire a technician to carry out blower door testing. For most new homes this testing will cost sev­
eral hundred dollars. Dollars saved in energy conservation from identified and corrected leaks may soon offset the cost of testing.

Thermal imaging using infrared cameras has rapidly become an affordable tool for diagnos­ing moisture problems. This versatile tool is also used for energy conservation audits (see the next section) and can detect overloaded electrical circuits, poor electrical connections, and “hot spots” on electrical equipment that may indicate a potential failure or fire hazard.

Infrared cameras are sophisticated devices that are used to examine the spectrum of en­ergy just outside our visual range. They “see” heat. We see the colors of the rainbow: violet, blue, green, yellow, orange, and red. Infrared is the portion of the spectrum just beyond red, which we can t see but can certainly feel with our skin in the form of heat.

Thermal imaging can frequently diag­nose moisture from leaks and condensation because damp surfaces are subject to evapo­rative cooling, resulting in cooler surface tem­peratures. Since thermal imaging uses surface temperature differences to indicate potential issues, moisture and missing insulation may appear the same. Thus moisture problems generally must have further diagnosis using moisture meters to confirm and identify the source of the moisture, but as a first screening step thermal imaging can help tremendously.

Energy Efficiency and Airflow Testing

Thermal Imaging for Energy Conservation Audits

When used by a knowledgeable, trained ther – mographer, an infrared camera can detect heat loss from missing insulation, air infiltration, and leaking ductwork. The US Department of Energy’s Office of Energy Efficiency and Re­newable Energy is now recommending that anyone purchasing a home have it scanned as part of the escrow. They advise: “Even new houses can have defects in their thermal en­velopes. You may wish to include a clause in the contract requiring a thermographic scan of the house”1

For thermal imaging to be most effective, there needs to be a temperature difference. In evaluations of ductwork and heating or air conditioning systems, the temperature dif­ferential is provided by the equipment being evaluated. In evaluations of energy efficiency from thermal insulation and of air infiltra­tion, there needs to be a sharp temperature

difference between the inside and outside en­vironments. Inspections of this type will be most effective when performed during the hot summer or cold winter months when there is at least a 20-degree Fahrenheit temperature difference between the inside and the outside of the building.

Newly constructed buildings generally have higher humidity levels caused by the moisture inherent in building materials and processes. It is important to dry enclosed buildings out quickly to levels that will not support mold growth and to verify that acceptable levels have been reached and are maintained. Hu­midity should be monitored and controlled from the time the building is enclosed un­til all wet-finish materials have been applied and dried. Humidity controls are especially important in humid climates or when mas­sive wet materials such as concrete or plaster are used. Inexpensive meters for determin­ing temperature and relative humidity called thermohygrometers can be purchased at most electronics and hardware stores.

Relative humidity (RH) varies depending on temperature. Warmer air will have a lower RH than colder air with the same amount of water vapor. With a special chart called a psy – chrometric table, a trained consultant can convert readings from the thermohygrome­ter to determine the actual amount of water in the air or at surfaces at various temperatures. These figures are used to determine if a struc­ture is dry enough. At 70 degrees Fahrenheit, mold will not grow at an RH level of under 60 percent measured at the surface. One way to measure the surface humidity is to affix the thermo hydrometer to the surface with a sheet of plastic sealed over it. After a few minutes the meter will stabilize and the RH can be read. If it is determined that humidity levels are too high, we recommend electric dehumidifica­tion. Note that if you can see condensation continuously on the windows for two days in a row, the building probably has areas that are wet enough to support microbial growth.

Certified water-loss technicians are trained and equipped to measure and dry buildings that have excessive levels of moisture. There are two associations that certify technicians and can help you locate qualified people in your vicinity. These are the Restoration In­dustry Association (RIA) and the Institute of Inspection, Cleaning and Restoration Certification (IICRC).

Calcium Chloride Moisture Testing

Large quantities of water are present in ce­ment, gypsum concrete, aircrete, and other poured masonry materials. These materials must be adequately dried before finishes are applied. It is common in new construction for a carpet or other floor finish to be laid on a slab before the slab is thoroughly dry. Further drying is inhibited, allowing microbial spore levels to climb as mold growth invades these damp areas.

Kits for testing moisture in masonry are available (see Chart 13.1). They contain cal­cium chloride salts, which absorb moisture from the air at a known rate. A kit contains a plate that holds the calcium chloride salt, a plastic dome, and an adhesive material. Weigh the calcium chloride to the nearest hundredth of a gram. (You can find scales for weighing the salts at your local pharmacy.) Then place the calcium chloride test plate on the floor area to be tested and cover it with the plas­tic dome, which is sealed to the slab with the adhesive material. After 60 to 72 hours, re­move the plastic dome and reweigh the cal­cium chloride. Based on the weight gain and the number of hours that have passed, you can determine the materials water vapor emis­sions rate. The kit instructions also contain a chart that will help you determine when the slab is dry enough for the application of var­ious finishing materials. If a scale is unavail­able, the sealed exposed kit can be shipped back to the manufacturer for weighing and calculations.