An amount provided by law that reduces taxable income or taxable value. Alternately, removal of property from the tax base, partially or completely. Exfiltration Air leakage from the interior of a building into the environment. Exfiltration Test Check for leaks in a buried water line by filling a manhole, by the part of the line in question, with water and watching it to find a sign of leakage. Exfoliation Physical weathering or chemical action creating a peeling off of some surface stone or masonry.
Moisture freezing in surface cracks causes expansion, creating exfoliation.
Exhaust Fan Ventilating device to remove smoke, undesired odors, stale or hot air or water vapor. Venting is normally done to the outside. Existing Grade Grade at an excavation site prior to commencement of work. Exit Passageway out of a building. Exothermic Chemical change in which there is a liberation of heat, as in combustion.