Home Inspection FYI

Providing Help, Knowledge and Other Useful Information To Home Owners Everywhere

Home Inspection FYI - Providing Help, Knowledge and Other Useful Information To Home Owners Everywhere

Category Archives: Air Quality

Central Humidifiers

Humidifiers are devices that humidify air so that building occupants are comfortable. Central humidifiers are hard-wired into a house’s plumbing and forced-air heating systems.

 

What is humidity?

Humidity refers to the amount of moisture in the air. “Relative humidity” signifies the amount of moisture in the air relative to the maximum amount of water the air can contain before it becomes saturated. This maximum moisture count is related to air temperature in that the hotter the air is, the more moisture it can hold. For instance, if indoor air temperature drops, relative humidity will increase.

How do central air humidifiers work?

Central air humidifiers are integrated into the forced-air heating system so that they humidify air while it is being heated. The water that is used by the device is pumped automatically into the humidifier from household plumbing, unlike portable humidifiers, which require the user to periodically supply water to the device. Humidifiers are available in various designs, each of which turns liquid water into water vapor, which is then vented into the house at an adjustable rate.

Why humidify air?

Certain airborne pathogens, such as those that cause the flu, circulate easier in dry air than in moist air. Moist air also seems to soothe irritated, inflamed airways. For someone with a cold and thick nasal secretions, humidifiers can help thin out the secretions and make breathing easier.

Indoor air that is too dry can also cause the following problems:

  • damage to musical instruments, such as pianos, guitars and violins;
  • dry skin;
  • peeling wallpaper;
  • static electricity, which can damage sensitive electrical equipment, cause hair to stick up, and can be painful or annoying; and
  • cracks in wood furniture, floors, cabinets and paint.

Central Humidifiers and Dangers

Humidifiers can cause various diseases. The young, elderly and infirm may be particularly at risk to contamination from airborne pollutants such as bacteria and fungi. These can grow in humidifiers and get into the air by way of the vapor where it can be breathed in. Some of the more common diseases and pathogens transmitted by humidifiers are:

  • Legionnaires’ Disease. Health problems caused by this disease range from flu-like symptoms to serious infections. This problem is generally more prevalent with portable humidifiers because they draw standing water from a tank in which bacteria and fungi can grow;
  • thermophilic actinomycetes. These bacteria thrive at temperatures of 113° to 140° F and can cause hypersensitivity pneumonitis, which is an inflammation of the lungs; and
  • “humidifier fever,” which is a mysterious and short-lived, flu-like illness marked by fever, headache, chills and malaise, but without prominent pulmonary symptoms. It normally subsides within 24 hours without residual effects.

Other problems associated with humidifiers include:

  • accumulation of white dust from minerals in the water. These minerals may be released in the mist from the humidifier and settle as fine white dust that may be small enough to enter the lungs. The health effects of this dust depend on the types and amounts of dissolved minerals. It is unclear whether these minerals cause any serious health problems;
  • moisture damage due to condensation. Condensed water from over-humidified air will appear on the interior surfaces of windows and other relatively cool surfaces. Excessive moisture on windows can damage windowpanes and walls, but a more serious issue is caused when moisture collects on the inner surfaces of exterior walls. Moisture there can ruin insulation and rot the wall, and cause peeling, cracking or blistering of the paint; and
  • accumulation of mold. This organic substance grows readily in moist environments, such as a home moistened by an over-worked humidifier. Mold can be hazardous to people with compromised immune systems.

Designs and Maintenance of Humidifiers212364 300 Central Humidifiers

  • drum-type humidifiers:  have a rotating spongy surface that absorbs water from a tray. Air from the central heating system blows through the sponge, vaporizing the absorbed water. The drum type requires care and maintenance because mold and impurities can collect in the water tray. According to some manufacturers’ instructions, this tray should be rinsed annually, although it usually helps to clean it several times per heating season.
  • flow-through or “trickle” humidifiers:  a higher quality though more expensive unit than the drum-type, which allows fresh water to trickle into an aluminum panel. Air blows through the panel and forces the water to evaporate into the air stream. Excess water exits the panel into a drain tube. This design requires little maintenance because the draining water has a “self-cleaning” effect and, unlike the drum-type humidifier, there is no stagnant water.

Other tips about humidifiers:

  • If equipped with a damper, it should be closed in the summer and opened in the winter. The damper may appear as a knob that can be set to “summer” or “winter” setting, or it may be a piece of metal that can be inserted to cover the duct opening.
  • The humidifier is controlled by a humidistat, which must be adjusted daily. Some new models do this automatically, although most require daily attention from building occupants. The humidistat should contain a chart that can be used to identify the proper setting based on the outdoor temperature. If this adjustment is not performed, condensation will likely collect on cool surfaces and potentially lead to mold or wood rot. Many homeowners do not know that this calibration is necessary.
  • The furnace might need to be checked for rust. Some humidifiers are installed inside the plenum of the furnace, which can be damaged by rust if the humidifier leaks.
  • Central humidifiers may have a solid core that should be replaced each year. The manufacturer’s instructions should be consulted regarding this replacement.

Central humidifiers are used to humidify air to make it more comfortable, but they can cause health problems and building damage if they are not properly maintained.

Thanks to Nick Gromicko, Rob London and Kenton Shepard of INTERNachi.
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Dust Mites

Dust Mites. What To Look For

Dust mites are microscopic arachnids that thrive indoors in warm, moist places, such as the insides of pillows and mattresses. They feed on dead skin that is regularly shed by humans and their pets. The harm posed to building occupants by dust mites is slight compared to other minuscule bed-dwellers, such as bed bugs.  Yet, unlike
dust mite Dust Mites those blood-sucking parasites, dust mites live in virtually every home and in large numbers. Due to their small size, access to copious quantities of food, and an insatiable desire to breed, dust mites can number 100,000 in just one square yard of carpet. They are a known allergen and can create allergic reactions in prone individuals, so it’s important to learn dust-mite detection and population-management strategies.

Size and Identification of Dust Mites

At just 0.42mm in length and 0.25mm to 0.32mm in width, typical dust mites are barely visible against a dark background in normal light, and a microscope is required to clearly see their features. Creamy blue in color and rectangular-shaped, they have eight hairy legs, and no eyes or antennae. While their presence can be confirmed microscopically, testing is an unnecessary expense because they virtually always show up in tests.

Allergies Caused From Dust Mites

Dust mites are medically significant because their feces contain a protein that can cause allergic reactions in certain individuals. The following are some of the more common allergy symptoms experienced by sufferers:
  • asthma and difficulty breathing;
  • in a child, frequent upward rubbing of the nose;
  • hay fever;
  • runny nose;
  • itchy, red or watery eyes;
  • nasal congestion;
  • itchy nose, roof of mouth and/or throat;
  • post-nasal drip;
  • facial pressure and pain;
  • cough; and
  • swollen, blue-colored skin under the eyes.

While there exists a genetic predisposition to allergic reactions, they can also develop over time, especially from childhood exposure. Eighteen to 30% of Americans are allergic to dust mites’ feces, and almost half of all American homes have dust mite allergen levels that are high enough to create sensitivity in people who were not previously allergic. A doctor can confirm a dust mite allergy using skin or blood tests.

Eradication and Management of Dust Mites

Disodium octaborate tetrahydrate powder is used to eradicate house dust mites. Non-chemical measures, such as limiting the availability of food, adjusting living conditions, and removing or killing the critters themselves can also be effective. Specifically, homeowners can practice the following management practices:

  • Reduce humidity levels. Studies have shown that the use of an air conditioner or electric blanket can dehumidify sufficiently to reduce the number of dust mites found in the home.
  • Dust. Before you vacuum, dust surfaces with a damp cloth, and be careful not to scatter the dust.
  • Vacuum. The vacuum is the most important tool in the homeowner’s dust mite arsenal. Thorough, regular vacuuming of carpets, furniture, textiles and other home furnishings will keep dust mite populations in check. Use a vacuum with a HEPA filter to avoid re-dispersal of dust into the home. The person with the allergy should not be the one performing the cleaning.
  • Use air purifiers. A HEPA filter air purifier will reduce the level of airborne dust mites. The effectiveness of these products is limited, however, as dust mites are generally not airborne.
  • Isolate pets. Pets create large amounts of dander, which is a food source for dust mites. Locate these pets’ sleeping quarters far from your own and in an area that can be cleaned easily, such as on washable hardwood or vinyl floors. If possible, avoid the adoption of excessively furry pets, and groom them regularly outdoors.
  • Isolate fabrics. Move all upholstered furniture, clothes, draperies, carpets and rugs away from the allergic individual’s sleeping quarters.
  • Reduce air infiltration. Open doors and windows can allow the entry of pollen, which serves as food for dust mites and is itself an allergen. Damp summer air can also flow indoors and increase humidity levels, which encourages the spread of dust mites.
  • Launder bedding. Research has shown that laundering with any detergent in warm water (77° F) removes nearly all dust mites from bedding. Ten minutes in a household clothes dryer at high temperatures will kill all dust mites in bedding.

Exaggeration and fear-mongering have spurred an entire industry of detergents, air filters and other products that purportedly protect building occupants against dust mites, which are harmless to those who are not allergic. These products often don’t work as advertised and are rarely as effective as the simple measures described. Do your research before buying into clever marketing, and be sure to hire an IAC2 certified InterNACHI inspector if you have any worries about household pests or air quality.

FYI, dust mites are small, house-dwelling critters that can create allergic reactions in sensitive individuals. Their numbers can be managed through relatively simple strategies.

Dust Mites 

 

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Sewer Gases in Your House

Sewer Gases

Decomposing waste materials in public and private sewer and septic systems create sewer gases. Methane is the largest single constituent of sewer gases, which includes an assortment of toxic and non-toxic gases, such as hydrogen sulfide, carbon dioxide, ammonia, nitrogen oxides, and sulfur dioxide. Improperly disposed gasoline and mineral spirits may also contribute to sewer gases.drain Sewer Gases in Your House

Sewer gases pose the following risks to building occupants:

  • hydrogen sulfide poisoning. Hydrogen sulfide is an explosive and extremely toxic gas that can impair several different systems in the body at once, most notably the nervous system. So potent that it can be smelled at 0.47 parts per billion by half of human adults, the gas will begin to cause eye irritation at 10 parts per million (ppm) and eye damage at 50 ppm. Other low-level symptoms include nervousness, dizziness, nausea, headache and drowsiness. Exposure to higher concentrations can lead to pulmonary edema, and still higher levels (800 to 1,000 ppm) will cause almost immediate loss of consciousness and death;
  • asphyxiation. When sewer gases diffuse into household air, they gradually displace oxygen and suffocate occupants. The effects of oxygen deficiency include headache, nausea, dizziness and unconsciousness. At very low oxygen concentrations (less than 12%), unconsciousness and death will occur quickly and without warning. Oxygen will be at its lowest concentrations in the basement, which is where heavy sewer gases, principally methane, are likely to collect;
  • fire or explosion. Methane and hydrogen sulfide are explosive components of sewer gas. Vapors from improperly disposed fuel can further increase the risk of fire or explosion; and
  • odor. Hydrogen sulfide is responsible for sewer gas’s characteristic rotten-egg smell, which can be overbearing even at extremely low concentrations. The gas’s odor is a safeguard, however, because it alerts building occupants to the leak long before they’re in any serious danger. It is important to note that at roughly 100 ppm, the olfactory nerve becomes paralyzed, removing the victim’s sense of smell and, subsequently, their awareness of the danger. Another “warning smell” comes from ammonia, which will sear the nostrils and progressively irritate the mucous membranes and respiratory tract. This gas, unlike hydrogen sulfide, is sufficiently irritating that building occupants are likely to vacate before its concentration rises to toxic levels.

If you suspect that any odors might be caused by sewer gases, contact a qualified plumber. Be sure to mention the smell of sewer gases to an inspector during your next scheduled inspection.

The design of the plumbing system relies on a connection between household fixtures and the sewer system, which is why a great deal of effort is spent to ensure that waste products — and the sewer gases that result from their decay — flow in one direction.
The following failures in the plumbing system may allow sewer gases to flow back into a building:
  • dried-out piping and plumbing fixtures. In most cases, intruding sewer gases are caused by a loss of the water barrier where traps have gone dry. Especially in dry weather, infrequent use of a toilet, shower or floor drain can allow for rapid evaporation and entry of sewer gases into the living space. Particularly common culprits are floor drains placed in locations where they are likely to dry out, such as near water heaters or furnaces, as well as seldom-used drains, such as those in janitor’s closets, workshop areas and mechanical rooms. Homeowners can maintain the water barriers by using the fixtures more often or by pouring water down the drains. Automatic drain-trap primers may also be installed so that a small amount of water is periodically delivered;
  • cracks in the plumbing drain line or vent pipes. A water leak typically accompanies a crack in the drain line, but vent pipe cracks are more difficult to diagnose, and they can vent a large quantity of sewer gases into the home. Plumbers can locate these cracks by using a special machine that generates artificial smoke and pumps it into the plumbing drain system. The smoke pressurizes the system and exits through any cracks or loose fittings;
  • diffusion from a leach field septic system;
  • sewer gases through cracks in a building’s foundation; and
  • plumbing vents installed too close to air intakes or windows in homes equipped with HVAC air handlers that admit outside air for ventilation. Wind and air flow around the building can allow for sewer gas to enter the building even where plumbing vents and air intakes are appropriately placed. Homeowners can add vent pipe filters or alter the height of vents to alleviate the problem.

 

FYI, the intrusion of sewer gases into the living space should be discovered and fixed before occupants suffer ill health.

 

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