Glossary
Plain-English definitions of mold inspection, sampling, water-damage, and standards terminology.
Abatement
Abatement is the regulated removal of a hazardous material; for mold the precise term is remediation, since mold is not a federally regulated hazard.
ACAC
The ACAC is an independent body that certifies individual environmental professionals, including the CMC and CMI mold credentials, by exam and experience.
ASHRAE Climate Zone
An ASHRAE climate zone classifies a location by temperature and moisture, which shifts what counts as a normal indoor spore count and humidity target.
Aspergillus/Penicillium (Asp/Pen)
Aspergillus/Penicillium is the combined spore-trap category for two genera whose spores look nearly identical under a microscope and are counted together.
Background Density
Background density is the count of inert debris and skin cells on a spore-trap slide; a heavily loaded slide can obscure spores and bias the result.
Bioaerosol
A bioaerosol is any airborne particle of biological origin, including mold spores, fragments, bacteria, and endotoxins, that an air sample can capture.
Bulk Sample
A bulk sample is a physical piece of suspect material (drywall, carpet, insulation) sent to a lab to confirm and identify mold growth on it.
Chain of Custody
Chain of custody is the documented trail of a sample from collection to lab analysis, proving who handled it and that it was not altered.
Clearance
Clearance is the independent post-remediation evaluation confirming a mold job returned the space to normal conditions before it is released for reoccupancy.
Condition 1, 2, 3 (IICRC S520)
Condition 1, 2, 3 is the IICRC S520 framework describing a mold remediation goal: normal fungal ecology, settled spores, or actual growth.
Containment
Containment is the physical barrier and pressure setup that isolates a mold work area so spores disturbed during removal do not spread to clean spaces.
ct/m3 (Counts per Cubic Meter)
ct/m3 is the unit air-sampling labs use to report fungal concentration, normalizing the raw count by the volume of air drawn through the cassette.
Culturable Sample
A culturable (viable) mold sample grows living spores on agar so a lab can identify species and report colony-forming units per cubic meter.
Dew Point
Dew point is the temperature at which air becomes saturated and water condenses; surfaces at or below it wet themselves and grow mold without any leak.
ERMI (Environmental Relative Moldiness Index)
ERMI is an EPA-developed research tool that uses DNA analysis of settled dust to score 36 mold species into a single relative moldiness number.
HEPA
HEPA is a filter grade that captures at least 99.97% of 0.3-micron particles, the standard for trapping mold spores during vacuuming and air filtration.
HERTSMI-2
HERTSMI-2 is a five-species subset of the ERMI dust-DNA panel, scored to estimate whether a water-damaged building is safe for a sensitive occupant.
IICRC
The IICRC is the standards body that publishes the S500 water-damage and S520 mold-remediation consensus standards used across the restoration trade.
Indoor:Outdoor Ratio
The indoor:outdoor ratio compares indoor airborne spore concentration to a same-day outdoor control to judge whether mold is amplifying indoors.
Moisture Meter
A moisture meter measures dampness in building materials by pin (resistance) or pinless (capacitance) sensing, locating wet zones that feed mold.
Mycotoxin
A mycotoxin is a toxic compound some molds produce; it is not the same as a spore and is not measured by a standard spore-count air sample.
Negative Air
Negative air is a HEPA-filtered machine that holds a containment under lower pressure than its surroundings, so leaks flow inward and exhaust filters clean.
Post-Remediation Verification (PRV)
Post-remediation verification is the inspection and optional sampling that confirms a mold remediation worked before an area is cleared for reoccupancy.
Relative Humidity (RH)
Relative humidity is how much water vapor the air holds versus its maximum at that temperature; sustained indoor RH above ~60% feeds mold growth.
Relative Moldiness Index (RMI)
The relative moldiness index is the scaled score behind ERMI: it ranks a home's dust-DNA mold profile against a national reference distribution.
Remediation
Mold remediation is the full process of fixing the moisture source and removing or cleaning contamination to return a space to normal fungal ecology.
Spore Trap
A spore trap is an air-sampling cassette that pulls air across a sticky slide so a lab can count total fungal structures by microscopy.
Stachybotrys (Black Mold)
Stachybotrys chartarum is a greenish-black, slow-growing mold that needs sustained wet cellulose and is the species behind most black-mold concern.
Swab Sample
A swab sample wipes a measured surface area with a sterile swab to capture mold for lab identification, useful on textured or irregular surfaces.
Tape Lift
A tape lift presses clear adhesive against a surface to capture mold for direct microscopy, the fastest surface method for confirming visible growth.
Thermal Imaging (Infrared)
Thermal imaging is an infrared camera technique that maps surface-temperature differences to reveal hidden moisture; it sees temperature, not moisture itself.
Vapor Barrier (Vapor Retarder)
A vapor barrier slows water-vapor diffusion through an assembly; placed wrong for the climate it traps moisture and causes the mold it was meant to prevent.
Water Activity (aw)
Water activity is the available water in a material on a 0 to 1 scale; most molds need an aw above about 0.8, which is why drying below it stops growth.
Water Category (IICRC S500)
Water category is the IICRC S500 system grading water by contamination, Category 1 clean to Category 3 grossly contaminated, driving the response.
Water Class (IICRC S500)
Water class is the IICRC S500 system grading a water loss by evaporation load, Class 1 least to Class 4 specialty drying, setting the drying effort.
WME (Wood Moisture Equivalent)
WME is a moisture-meter reading scaled to the equivalent moisture content of wood, letting one wood-calibrated scale read many materials comparably.