are the sixth-leading cause of chronic disease in the
United States and are estimated to cost the health care system
more than $18 billion annually.
It is estimated that up to 50 million Americans have
allergic diseases. Statistics show that allergies are present in
as many as 78 percent of asthmatics and can trigger asthma attacks. The prevalence of asthma is increasing rapidly
in the United States, and the disease causes more than 5,000
Factors contributing to allergic diseases include
allergen sensitization, continued allergen exposure, and environmental
irritants. The most common
exposure route for allergens is through inhalation, but also
includes ingestion and contact with the skin and mucous membranes.
One very common cause for indoor allergen exposure is
through water damage to building structures and subsequent mold
growth. Mold growth may appear within 48 -72 hours
of water intrusion if not properly re-mediated. Molds, both indoors and outdoors, can be an enormous factor contributing
to allergies. Sampling
for molds can be an excellent indicator and cost effective means
of determining possible environmental factors contributing to
effects vary tremendously, depending on the individual, dosage,
and route of exposure. The
fact that the bacteria do not have to be alive for endotoxins
to pose a serious health threat is the main impetus for concern.
One major route of exposure is in the bloodstream, which
on occasion, occurs by absorption through the gut.
Although gram-negative bacteria are normal inhabitants
of the gastrointestinal tract, when the natural host defenses
are impaired, bacteria can be introduced into the bloodstream
or lymphatic system. Another
way that bacteria can enter the bloodstream is by infection
of by introduction in surgical procedures or medicines.
Once in the bloodstream, endotoxin levels as small as
two hundred parts per trillion (on a body weight basis) causes
fever and as small as one part per billion can cause shock and
death. In response to
this very real potent threat, medical device manufacturers and
pharmaceutical companies now routinely test all of their products
to ensure that they are free of endotoxins.
Another way individuals may be exposed to endotoxins
is by inhalation of bacterial cells or fragments, which is the
object of this discussion. Reported
acute symptoms of inhaled
Exposure to saprophytic fungi (molds) in
indoor environments has been linked to a number of adverse health
effects including, but not limited to, lethargy, allergies,
asthma, infection, dermatitis and hypersensitive pneumonitis.
While the aforementioned symptoms are intuitive and largely
recognized by both the scientific and lay communities, there
are significant secondary health effects associated with exposure
to fungi, including idiopathic pulmonary hemosiderosis in infants,
cytotoxicity, cognitive impairment, encephalopathies, immunosuppression,
Research indicates that these secondary health effects
may be caused by the mycotoxins produced by the fungi. Although
still controversial, in the end mycotoxins may prove to be major
components in the health effects reported by victims of fungal
MOISTURE THE CAUSE OF THE PROBLEM:
THE CAUSE OF MOISTURE
search for the cause of the excess moisture that promotes microbialbal
infestations runs an often predictable course.
Roofs, windows, HVAC, plumbing, irrigation systems and
water evacuation systems should all inspected and evaluated.
construction defect (CD) attorneys now believe that water damage
plays a leading role in nearly all construction defects cases.
Therefore water intrusion are important because of the
consequential damages generally attributed to such water damage
and roofs are a prime candidates for providing the leaks that
afford consequential damages to so many construction elements
in all types of buildings. During
testing procedures, if a window leaks it leaks either at the
window product corners or at the frame, or at the sill track
due to overflowing or with the glass installation or window
itself or any combination of these various indivdual problems. Although this leaking problem is found to be
quite common, it is the installation of the windows rather that
the window product that most often reveals a leak.
When selecting windows for random testing, the preferred
windows selected for testing should be free from apparent water
staining on the surrounding plaster so as to assure a random
sampling. Windows with plaster stains or plaster deformations
around them should be summarized in a separate category for
most important area of window installation, is the installation
of the surrounding flashing during framing procedures. This necessary flashing element requires that its installation be
correctly integrated with the stucco lath so as to assure its
water-tight integrity. There
are literally dozens of ways to install this required flashing,
but only a couple of ways to install it correctly so as to prevent
leaks into the building envelope.
upon invasive investigation, it is often found that the flashing
installers have selected one of the many incorrect ways.
Even when the flashing is correctly installed it is often
found that the stucco lathing installer failed to properly integrate
the lath with the flashing. The result is that the system as installed will
leak into the interior of the building, sometimes with a tiny
drip and sometimes with a small stream of water.
The interior insulation will absorb some of the moisture
as will the lumber and the interior of the gupsum plaster with
this moisture providing the catalyst for the necessary food
source for the growth and propagation of the fungi and mold.
of the most common sources of leaks accompanied by consequential
damages, are roof leaks. The
materials utilized generally being up to the industry standards,
but the methods used in applying the various roofing elements
into a watertight cohesive bundle, are frequently inadequate.
Roof leaks are sometimes hard to locate, with some manifesting
themselves hundreds of feet from the source of the leak source,
but are often more complex from a discovery point of view as
well as from the remediation requirements. The faulty installation of the various component parts, especially
the proper integration of the sheet metal flashing and counter
flashing elements, is a prime source of serious water leaks. To a less frequent degree HVAC units, irrigation
lines, drain lines, on grade slabs and sewer lines all can cause
damage with consequential effects.
When any of these leaks occur, numerous other construction
elements can be impacted, some with serious side effects.
most construction defects cases start off with a leak from either
plumbing lines or from exterior sources, it is imperative that
measures be taken to ensure that water pipes are not leaking
and that the exterior elements of the house are in a watertight
these and other potential sources don't answer your questions,
it may be wise to look under foot.
Vapor transmission in concrete slabs is the leading cause
of flooring material failure. The same vapor that causes a failure in floor
coverings can be the source of microbe promoting moisture.
transmits from the ground, through the slab, and into the building
envelope by a difference in Vapor Pressure.
Vapor Pressure is a number mathematically derived from
a combination of temperature and humidity.
If sub-slab conditions are damp and cool, the warmer
and dryer the building envelope is the greater the emission
levels will be produced.
indicators of concrete slab vapor transmission include:
or bubbles in sheet vinyl flooring,
lines and curling in vinyl composition tile,
under boxes and chair pads,
glue carpet peels back easily,
slab is a dark gray under the flooring,
slab has no vapor barrier,
Tests and inspection of underground pipes shows them
to be in poor condition,
a proper vapor barrier is used for the construction of the slab
the only major concern is with the water in the concrete.
If there is no vapor barrier, any testing is only a snapshot,
and will most certainly vary with the exterior and interior
environmental changes. The transmission of vapor cannot be controlled
by HVAC systems alone. The
floor must be correctly sealed in order to bring emission levels
into compliance. Testing is done using anhydrous calcium chloride.
Test results are expressed as pounds of water per 1,000
square in 24 hours.
flooring industry standard for most applications limits the
allowable level to below 3 pounds. Experience shows that some
floor coverings can handle higher emissions.
Among these are vinyl composition tile, ceramic tile,
and glue down carpet. If there is a failure of any floor covering, there may be enough
vapor to promote microbial growth.
If no failure is evident, there can still be emission
levels high enough to cause problems.
contamination due to concrete vapor slab transmission is another
area that should be considered.
Under certain conditions microbial growth will occur
from failed or non-existing flooring vapor barriers and this
can have an enormous effect on the formation of bioaerosols
and subsequent poor air quality.
Proper vapor barriers are essential to prevent vapor
transmission that can lead to this microbial contamination.
significant facet of many indoor air quality microbial investigations
is the assessment of the carpeting in an occupied building. Carpet is listed as one of the nine potential
sources of biological agents in an occupied space by the American
Conference of Governmental Industrial hygienists. The difficulties in assessing carpet contamination arise from the
porous nature of the material, lack of standardized sampling
methods, and obscurity of data interpretation.
can be found in almost any building.
The aesthetic values of sound dampening and enhanced
appearance are important to a productive work environment and
a comfortable home environment.
Carpet can also be a reservoir for many contaminants
including dust, pollen, bacteria, and fungi.
These contaminants are typically ubiquitous in most envireonments,
but complications arise with poor carpet maintenance (cleaning)
and/or water damage incidents.