10 Oct

Bug Zappers

by Nick Gromicko

A bug zapper is a popular exterior appliance installed by a homeowner or food handler to attempt localized control of flying insect populations. Its name comes from the characteristic “zap” sound

produced when an insect is electrocuted. Around homes, they are primarily used to kill biting (female) mosquitoes, which create itchy bumps and can transmit the West Nile Virus or encephalitis, malaria and yellow fever. While Popular Mechanicsproduced a sketch of a bug zapper as early as 1911, it wasn’t until 1934 that parasitology professor Dr. W.B. Herms introduced the electronic insect killer that became the model for all future bug zappers.

How They Work

Bug zappers typically consist of the following components:

the housing, which is a plastic or grounded metal exterior casing that contains the zapper’s parts. It may be shaped liked a lantern, a cylinder or a rectangular cube. A grid design may be incorporated to prevent children and animals from touching the electrified grids inside the device;
a light source, which is usually fluorescent-type, such as mercury, neon or ultraviolet light;
wire grids or screens, which are electrified layers of wire mesh that surround the light source. These grids are separated by a tiny gap roughly the size of a typical insect (several millimeters); and
the transformer, which is the device that electrifies the wire mesh, changing the 120-volt, electrical-line voltage to 2,000 volts or more.

Bug zappers work by luring flying insects with fluorescent (typically ultraviolet) light into a deadly electrical current. Because the flower patterns that attract insects are better revealed in ultraviolet light, many flying insects that feed on flowers will be drawn to the bug zapper. Before they reach the light, however, they will come into contact with the wire mesh, completing the electrical circuit and disintegrating.

Bug zappers can kill many thousands of flying insects nightly. Some models incorporate a tray designed to collect scattered insect parts, although many models allow the debris to fall to the ground below.

Effective or Not?

Despite their widespread use, numerous studies have called into question the effectiveness and safety of bug zappers. Two of the more pressing issues are the following:

Female (biting) mosquitoes and other biting insects are more attracted to the carbon dioxide (CO₂) and water vapor in the breath of animals than to ultraviolet light. As a consequence, standard bug zappers typically kill large numbers of harmless and beneficial insects, such as beetles and fireflies, and ultimately fail to reduce the number of the types of insects that prompt the purchase of a bug zapper in the first place. In fact, one study found that just 0.22% of the insects killed by bug zappers were biting insects, while nearly half of those killed were harmless, non-biting aquatic insects from nearby rivers and streams. The study even found “the probability of being bitten by mosquitoes increases in the vicinity of these traps,” perhaps because the biting insects are actually lured by the ultraviolet light but become distracted by the far more attractive human prey nearby. Some newer bug zappers address this issue by incorporating a CO₂ container at the bottom of the lamp. Other designs attract mosquitoes into a netting device on the outside of the bug zapper that traps the mosquito, and eventually the insect dies of dehydration.
The electrocuted insects are blasted into a fine mist that contains insect parts as well as unkilled bacteria and viruses up to 7 feet (2.1 m) from the device. The air surrounding the zapper may become contaminated with campylobacter jejuni, staphylococci, serratia marcescens, enterococci, and other potentially dangerous organisms commonly carried by flies. For this reason, a bug zapper should never be placed over a food preparation area or in a hospital or any other sterile environment to prevent the potential spread of disease. Children should not be allowed to play beneath an operating bug zapper. Models that contain a tray to catch insect debris are less of a health risk.

Tips for Homeowners

Bug zappers do not present more of a fire hazard than other electrical devices. Most units have been UL-tested, but, as with any outdoor electrical appliance, care must be taken to ensure that electrical cords do not become frayed or wet. They should also be connected to GFCI-protected receptacles.

Inspectors may pass on the following mosquito-control techniques to concerned homeowners:

Do not allow water to accumulate anywhere in your yard for more than a few days. Eliminate sources of standing water, especially old tires, flower pots, clogged gutters, tin cans or buckets. Fill in or drain ruts, puddles and other low places in the yard. Even holes in trees from rot and hollow stumps can collect water that can harbor mosquitoes. Cover trash containers to keep rainwater out, and drill holes in the bottom of trash containers to allow any water to drain. Repair leaky pipes and outdoor faucets.
Bug zappers should be cleaned out at least annually to prevent the accumulation of bug parts on the wire mesh, which will decrease the effectiveness of the unit, and may lead to illness if the bug parts contaminate foods, drink or items used by people or pets.
Keep grass cut short and any shrubbery well-trimmed, as adult mosquitoes use these places to rest and hide.
Encourage the presence of bats by installing a bat house. These winged mammals pose little danger to humans, and a single brown bat can consume up to 600 mosquitoes per hour.
Install a fan. Mosquitoes and other flying insects will avoid moving air.
Wear long-sleeve shirts and pants. The pesticide permethrin may be applied to clothing to protect against mosquitoes and ticks. Beware that while permethrin is relatively safe for people and dogs, it is toxic to cats.

In summary, bug zappers are a common yet controversial means of controlling biting insect populations around the home, and caution should be taken in their selection and use.

10 Oct

The Dangers of Brominated Fire Retardants

by Nick Gromicko

Brominated flame or fire retardants (BFRs) include a wide range of chemicals added to household furnishings and products to inhibit their ignition and reduce the chance of fire. In recent years, concern surrounding the toxicity of this class of chemicals has risen due to the widespread accumulation of several types of BFRs in humans and in the natural environment. BFR can be found in many household products, especially older appliances and textiles

BFR can be found in many household products, especially older appliances and textiles

There are more than 175 different types of flame retardants, which are generally divided into classes that include brominated, chlorinated, phosphorus-containing, nitrogen-containing, and inorganic flame retardants. Producing BFRs, at a rate of 5 million metric tons annually, is a $2 billion business, and this particular arm of consumer fire safety is currently the industry leader. For several decades, BFRs have been routinely added to consumer products, including computers, TVs, electrical cables, carpets, furniture and textiles, in a largely successful effort to reduce fire-related injuries and property damage.

BFRs are found virtually everywhere in the environment, from house dust and indoor and outdoor air, to sediments in rivers, estuaries and oceans. BFR contamination has been discovered in polar bears, eagles, and even in the blubber of sperm whales in the deep, remote waters of the Atlantic Ocean. High levels of the chemicals have been found in the atmosphere and rivers near urban and industrialized areas. Perhaps the greatest concern, though, is the concentration of the chemicals found in the blood of office workers and in human breast milk, where it can be transferred from mother to child.

One type of BFR is TBBP-A, which has been linked to breast cancer, and has been shown in mice and rats to disrupt the thyroid hormone system, which plays a crucial role in the development of the brain and body. Laboratory research has demonstrated that low-level exposure of young mice to PBDE – another BFR — causes permanent disturbances in behavior, memory and learning. Linda Birnbaum, a toxicologist with the EPA, told CBS News that PBDEs “can affect the developing brain, and they can affect the developing reproductive system.”

The World Health Organization has called for disuse of PBDEs where adequate alternatives are available, and the Swedish Chemicals Inspectorate has called for the chemicals to be entirely phased out. By contrast, the UK Department for Trade and Industry calls fears over PBDEs “chemical paranoia,” arguing that there is no conclusive proof that BFRs are harmful to humans. Still, the European Union has banned PBDEs in electronic devices, and in the United States, PBDEs are now heavily regulated, notably in Washington state, Maine and California.

Alternatives to BFRs that provide comparable fire safety are available, and many products have been redesigned so that flame-retardant chemicals are unnecessary. Apple and Sony have changed the casing material for the MacBook Air and Vaio, respectively, in order to reduce the need for flame-retardant additives. However, BFRs are still used in a wide array of products, and testing for the presence of the chemicals is difficult for the layperson.

In summary, BFRs, although highly regulated, continue to pervade homes and the natural environment, exposing humans and animals to potential danger.

10 Oct

Blower Door Testing

by Nick Gromicko and Ethan Ward

What is a Blower Door?

Inspectors should become familiar with blower doors, as they can be a valuable tool in energy audits. A blower door is a powerful, variable-speed fan that can be temporarily mounted into an exterior door frame to provide controlled air flow for analysis. The way that air flows through a building can have a serious impact on air quality, comfort and energy expenses. The use of a blower door allows air flow through a structure, and the resulting loss of heat can be immediately quantified, providing a way to pinpoint the location of air leaks.

Blower doors were originally developed in the 1970s for use as a research tool. As technology has evolved, allowing for the development of more portable equipment, blower doors have transitioned into use as a valuable field tool, as well. The first portable blower doors weighed as much as 200 pounds and took up quite a bit of space, and were also very expensive. Today, they are much more affordable and are built lighter and smaller. The reduced set-up time allowed by their more compact designs has led to the standard use of blower doors as part of energy audits for measuring air flow.

How It Works

When air pressure and air flow are controlled and measured, they can provide data about how airtight a building is. The three variables involved are pressure, flow and holes or leaks. A change in one of these factors will produce a change in at least one other factor. Since the goal of a blower door test is to locate air leaks in the building envelope, data regarding air pressure and flow can provide information about the holes, which may otherwise be tough to find.

The blower door utilizes controlled differences in air pressure to collect data. Once installed in an exterior door frame, the air pressure inside a building can be changed in relation to the outside pressure by forcing air into or out of the interior. The difference in pressure forces air through holes or leaks in the building envelope. The pressure and air flow are measured by gauges, which are part of the blower door equipment. By measuring the pressure and air flow in relation to each other, the airtightness of the building envelope can be quantified. The amount of air flow needed to create a change in pressure increases as the airtightness of the building envelope decreases. A well-sealed building requires less air flow to generate a change in pressure.

Finding the Problems

During a blower door test, the interior air pressure needed to be maintained in order to gather useful data is 50 pascals, which is roughly equal to the pressure created when a 20-mph wind hits the building. The blower door equipment has a gauge to indicate when this pressure has been achieved, as well as a gauge to indicate the cubic feet per minute (CFM), which is the standard unit of measure for air flow. Air flow in a well-sealed building will generally be less than 1,500 CFM at 50 pascals. Air flow above 4,000 CFM would be considered leaky. This is valuable data that can be acquired in about half an hour with the use of a blower door.

Since the blower door forces air through cracks and holes, the locations of the leaky spots can be identified. The draft of air entering through the holes can often be felt with the hand. Smoke and infrared imaging can also be employed to locate smaller, more subtle leaks. It is often assumed, especially by homeowners, that poorly sealed windows and doors are the major culprits of air leaks. In reality, leaks in other areas are usually much more significant. The difference in air pressure between the interior and the exterior is greater both at ground level and up high, so leaks in basements and crawlspaces, as well as in attics, are the most important to locate.

When looking for air leaks, check through basement rim joists, holes for plumbing traps under tubs and showers, cracks between finish flooring and baseboards, utility chases, plumbing vent-pipe penetrations, kitchen soffits, fireplace surrounds, recessed can lights, and cracks between partition top plates and drywall. These are all common places where significant leaks can develop.

Accounting for Outside Factors

Wind and temperature can have an effect on the test data. Wind blowing on the outside of the building can add to pressure differences between the interior and exterior. It can also affect the flow rate of the blower fan. It is best not to conduct blower door tests in windy conditions. But if wind is not severe, tests can be conducted at multiple points in the building and then averaged together.

Differences in temperature can create differences in pressure. Accounting for a baseline stack-effect pressure will ensure that the test results are not skewed. The stack-effect pressure is a function of the height of the building and the difference in temperature from the interior to the exterior. A 15-foot tall building with a 50º-temperature difference between the inside and outside will have a 5-pascal pressure difference from the top of the building to the bottom. Some blower door equipment has a gauge with a built-in baseline feature, so this difference can be easily determined at the outset of the test.

Temperature and barometric pressure affect both air density and viscosity, which is its resistance to flow. Because of this, an adjustment for density is required. Some software packaged with blower door equipment is designed to make these calculations, and if it is not available during the test, the manual supplied with the equipment should have information about making the necessary adjustments and applying it to the results.

Preparation and Safety

In order to ensure accurate results, as well as safe conditions for performing the test, some preparation is necessary before beginning. Any fireplaces or stoves used for heating should not be operating, and all furnaces and pilot lights should be turned off. There should be no open flames anywhere indoors. Ashes in fireplaces or stoves should be removed so they do not get sucked into the building. Dampers should be closed. Every door and window must be closed tightly so that air flowing through them does not affect the test, while all interior doors should be left open.

If there is a basement, it must be determined whether this area is to be considered part of the building envelope for testing purposes. Generally, if there is heat in the basement, even if only because the furnace is located there, it will be considered part of the envelope, and access to it should be left open during the test. Sometimes, the test may be done both ways — with the basement access open and with it closed, and this is quick and simple to accomplish.

Since blower door testing is a standard tool used during an energy audit, it is helpful for inspectors to understand how the test works. Knowing a bit about the outside factors that can influence the results will ensure that the test is performed correctly. Setting up the equipment properly will ensure that testers and occupants are safe, and that the testing and results are accurate.

10 Oct

Bidets

by Nick Gromicko and Kenton Shepard

Common in much of Europe and Asia, bidets are toilet-like plumbing fixtures designed to promote posterior hygiene. Although bidet prevalence in certain regions represents a humorous cultural distinction from American-style paper wiping, bidets do sport considerable convenience and comfort advantages. Bidets are becoming increasingly common in North America and it is important that first-timers and home inspectors understand how they operate.

Contrary to popular belief in regions where they are uncommon, bidets are not toilet alternatives. They are used to wash the anus, inner buttocks, and genitalia, usually after the user has defecated into an adjacent toilet. Some bidets have been incorporated into toilets, especially in bathrooms that are not large enough for both fixtures. Bidets, like toilets, are typically made from porcelain and contain a deep recess within a wide rim. They emit an arc of clean water from a nozzle that can either be beneath the rear of the rim or deep within the fixture cavity. Users can sit on the rim (or seat, if it has one) or straddle the fixture and face in either direction. He or she can decide which direction to face based on the water jet configuration and the part of their body that needs cleaning. Water temperature and pressure can be adjusted with knobs in order to arrive at the desired settings.

Some bidets come with built-in air dryers that can be used to dry wet areas. Toilet paper can be used for this purpose if no dryer is available. The bidet can be rinsed after use to keep it clean.

Benefits

People who suffer from hemorrhoids, irritable bowel syndrome, or have recently had rectal surgery can find relief from painful paper wiping with the more gentle water flow of a bidet.
As the bidet requires less operator mobility, they are easier to use for the elderly, disabled, and obese.
Many believe that the use of bidets is more hygienic and effective than toilet paper. Regardless of this claim’s validity, the user has the option to use both methods if they desire.
Bidets eliminate the expense of toilet paper.

Some Fun Facts About Bidets

Although bidet is a French term, the fixture is more common in other European countries such as Italy and Portugal.
The first bidets appeared in France in the early 1700s, although no one knows exactly who invented it or when this happened.
In the Unites States, bidets are more expensive (around $400) than in countries where they are common, perhaps contributing to their rarity.
Google headquarters in Mountain View, California, offers employees the most technologically advanced bidets on the planet. Employees can use a remote to control spray strength, seat temperature, vibration, and deodorization.
A bidet for travelers who need to use them on the go is called a bidanit.

Safety Precautions

InterNACHI inspectors can pass along the following tips to their clients:

Users should familiarize themselves with the rate of temperature and pressure changes that occur when they adjust the controls. Sensitive regions can be burned if the user is not careful, and high water pressure can be irritating.
Bidets have the potential to transmit contagious diseases. This is of greater concern in public restrooms than in homes.
Users should know in advance the direction of the water arc and position themselves accordingly. The spray can be powerful enough to strike a person in the face.
Infants should not be bathed in a bidet, as this is unhygienic. An exception can be made if a bidet is solely devoted to this purpose.
Bidets operate and appear similar to drinking fountains, although the two should never be confused. The bidet’s water jet can touch an unclean surface and become contaminated.

In summary, bidets are more than just an amusing European curiosity. Despite their expense in the United States and Canada, they are becoming more popular in these regions, and for good reason – many believe they are more sanitary, comfortable, and effective than toilet paper. It is a good idea for home inspectors who are not familiar with these devices to learn the basics so they can inform inquisitive clients.

10 Oct

Bed Bugs

Bed Bugs: Inspecting for the New “House Herpes”

by Nick Gromicko

Bed bugs are small, flightless, rust-colored parasites that feed on the blood of humans and other warm-blooded animals. Inspectors should learn the telltale signs of these pests and be capable of providing information to their clients. Adult bed bug

Bed bugs were diminished to an historical footnote after their near-eradication in the 1950s, but they are re-emerging in a big way. At the EPA’s National Bed Bug Summit in 2009, researchers decided that the parasite’s revival is more appropriately termed a pandemic rather than an epidemic, noting its rapid spread across large regions and different continents. For those afflicted by the bug, humiliated and defeated by its persistence, many prefer to refer to the infestation as “house herpes.” The United States has seen a 50-fold increase in bed bug infestations over the last five years, according to the National Pest Management Association. An entomologist told MSNBC, “It’s like the return of the wooly mammoth,” as many of his peers had previously never seen a single bed bug in their careers. The outbreak has affected most parts of North America and Europe, especially in urban areas.

Researchers believe bed bugs have roused from a half-century of hibernation for two reasons: the termination of the use of the pesticide DDT; and a rise in international travel. DDT, a powerful synthetic pesticide, was used widely in agriculture until a public outcry concerning its safety lead to a US-ban of the chemical in 1972, followed by international bans. Unbeknownst to the environmentalists of the time, these laws would permit future outbreaks to grow unchecked, which is precisely what happened when travel increased from countries where bed bugs were never subjugated, such as India.

Hotbeds of international travel, such as New York City, have hosted the bulk of the carnage. The bugs hitch rides from country to country in suitcases, and creep into hotel rooms where other guests are then exposed and unknowingly spread the parasites to movie theatres, cabs, buses, hospitals, houses, and everywhere in between. In New York City, bed bug reports increased 800% from 2008 to 2009, a year in which the Department of Housing Preservation and Development received 13,152 bug infestation complaints. Bed bug bites

The unpleasantness of a typical rodent or insect extermination is largely the fee charged by the exterminator. But with bed bugs, this fee is just one piece of a greater nightmare. Because bed bugs are adept at hiding almost anywhere, an alarming quantity of possessions, from curtains to books and picture frames, must be discarded or quarantined. In one posh New York City rental tower, a tenant was forced to part with carpets, bedding, curtains, 20 cashmere sweaters, an Armani suit, a couch, a headboard, a night table, a bedframe, and an exercise bike, according to the New York Daily News. Other victims have had to throw away their books unless they were willing to inspect each one, page by page. Some possessions may be salvaged if they are sealed in special casing long enough for the bed bugs to die, which can takes many months. During this time, residents may be forced to move to temporary housing elsewhere.

Fortunately, the health dangers posed by bed bugs seem to be limited to temporary skin irritation and inflammation, akin to mosquito bites. There are no known cases of disease transmission from bed bugs to humans, despite the fact that the parasites seem similar to other parasites that do transmit disease, such as fleas and ticks. Anaphylactic shock, however, may be experienced by a small percentage of the population, and measures should be taken to prevent bacterial infection of bitten areas.

Adult bed bugs are flat, apple-seed sized with rusty-colored, oval bodies. Newly hatched bed bugs are semi-transparent, light tan in color, and the size of a poppy seed. Yet, due to their elusive nature, their presence is usually discovered through peripheral clues rather than by seeing the bugs themselves. Some of these signs include fecal spots, blood smears, crushed bugs, or the itchy bumps that may result from bites. Bugs may be disturbed while feeding and leave a cluster of bumps, or they may bite in a row, marking the path of a blood vessel. The parasites emit a characteristic musty odor, although the smell is sometimes not present in even severe infestations. The bugs also emit a smell that is detectable by dogs, which has lead to the implementation of dogs in bed bug detection. Properly trained dogs can find bed bugs in wall voids, furniture gaps, and other places that humans may overlook and, in doing so, they focus on the area in which exterminators must spray. Bed bugs, their eggs and excrement

It is best for bed bugs to be treated by pest management professionals (PMPs), not homeowners, as there is risk that an inexperienced person may spread the infestation further throughout the home. For instance, bug bombs will be ineffective and merely spread bed bugs. Even chemical sprays designed to kill bed bugs, if used by inexperienced homeowners, may make the infestation worse. PMPs can inspect for bed bugs in their immature stages of development, including their eggs, while homeowners cannot. In addition, prep work performed by a homeowner may make it difficult for the PMP to assess the extent of the infestation.

The following tactics may be useful, however, for temporary relief or confirmation of the presence of bed bugs:

Remove bed skirts, as they provide easy access for the bugs to travel from the floor to your bed. If you must have bed skirts, make sure they do not reach the floor.
Move your bed away from the wall. Bed bugs cannot fly, but they can climb walls in order to fall onto the bed.
Place furniture legs in tin cans coated with talcum powder, petroleum jelly or a non-evaporative liquid, to deter the bugs from climbing.
Place a strip of duct tape at the base of furniture with the sticky side out. This tactic can be used to confirm the presence of bed bugs because it will trap them in place.
Spray cracks and crevices with an insecticide designed to control bed bugs. Follow the label’s directions carefully. However, do not treat bedding, towels or clothing with insecticide.

Homeowners can limit their chances of bed bug exposure by purchasing only new furniture, as stowaway bugs can hide in older or used chairs and mattresses. Hostels, hotels and motels host many travelers and are obvious breeding grounds for bed bugs, and many hostels ban sleeping bags for this reason. Unfortunately, person-to-person contact is difficult to avoid.

In summary, bed bugs are a growing, serious threat. Along with wood-destroying organisms, inspectors may want to enhance their knowledge by learning to recognize and become familiar with the problems posed by bed bugs because of their potential to infest homes and damage property.

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Author Archives: bwisnewski

Bug Zappers

Bug Zappers

The Dangers of Brominated Fire Retardants

The Dangers of Brominated Fire Retardants

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Bed Bugs: Inspecting for the New “House Herpes”

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