Environmental Engineering Reference
In-Depth Information
These would include large volumes of pressed wood products bonded with
urea-formaldehyde resins (e.g., particle board, hardwood paneling,
medium-density fiber board [MDF]); malfunctioning space and/or water
heaters; mold-infested materials; hobbies/crafts (e.g., silk screening, stained
glass, etc.); pets; insect infestations; recent pesticide applications; lead-based
paint; etc.
The inspection should include an evaluation of any structural problems
such as water-damaged interior/exterior materials, rotting timbers, damaged
gutters, cracks/holes in brick veneer, and wet basements/crawlspaces. It
should include a site evaluation as well. Site conditions of note include mod-
erate to heavy shade, poor site drainage as evidenced by ponding after rains,
moss growth, frost heaving, capillary wicking on substructure walls, etc.
Heating/cooling system appliances, including hot water heaters, should
be inspected, as well as associated flue systems and supply and cold air duct
systems. Evidence of flue gas spillage (in the absence of CO measurements)
can be determined from condensation stains and corrosion on draft hoods
and flue pipes as well as the design and assembly of flue pipes.
The location of furnace/air conditioner/blower fans and return air ducts
is important in conducting a building investigation. The presence of such
systems in musty basements or wet crawlspaces provides a pathway for the
transport of mold spores from an infested source to spaces throughout the
home. Ductwork in slab-on-grade houses should be inspected (by opening
supply air registers) to determine whether water entry occurs, if insect/dust
contamination is present, and what materials ducts are made of.
During the on-site investigation, an intensive interview should be con-
ducted with an adult occupant to better define the nature of health problems
experienced as well as to gain additional information on various factors
observed during the inspection of the interior and exterior of the home. This
interview may provide information on aspects of the inspection that might
require more detailed evaluation.
Air/environmental testing may be conducted to confirm and elucidate
the nature of the problem. Air testing for HCHO is desirable if evidence
indicates that occupants have been experiencing symptoms consistent with
the presence of significant HCHO sources. Carbon monoxide testing is
appropriate if symptoms are characteristic of CO exposures or there is visible
evidence of flue gas spillage. Air testing for mold using both culturable/via-
ble and total mold spore sampling is desirable if the building environment
has been subject to moisture problems with or without evident mold infes-
tation. The use of a portable flame ionization detector (FID) to determine
sources of methane would be appropriate if a sewer gas problem appears
to exist without an evident source. Surface dust sampling and monoclonal
antibody testing for dust mite, pet, and cockroach allergens may be appro-
priate in cases where health histories are suggestive of inhalant allergens. A
role exists for air testing and environmental sampling in conducting resi-
dential building investigations. That role is to confirm a hypothesis or to
more fully evaluate the nature of a problem.
