Application Note

2 Fluke Corporation Indoor air quality monitoring made easy with the Fluke 985 Particle Counter
IAQ investigation
An IAQ investigation is the first step in an ongoing
maintenance program or in responding to com-
plaints potentially associated with air quality. No
matter it is commercial/residential or industrial/
institutional environment, the methodology is
similar:
1. Conduct a survey of credible staff at the facil-
ity. Who has filed complaints, and what are the
symptoms? Are those who complained centrally
located, or dispersed throughout the facility? The
purpose is to gauge the level of toxicity or con-
centration as evidenced by allergic reactions or
irritation in human comfort or increased contami-
nation in product.
2. Research the building’s history. When was the
building built and/or remodeled? Have there
been any instances of excessive damage, and
how were the repairs carried out? What are the
maintenance practices within the facility? For
example, roof or plumbing leaks may have been
repaired, but the underlying water damage may
not have been addressed.
3. Perform a physical inspection. Technicians
need to be aware of their test environments by
considering harmful particulate sources. Within
a given location, areas containing exhaust vents,
furnaces, cleaning supplies, as well as areas with
fresh paint and/or carpeting must be accounted
for, especially if present within a complaint area.
Are there any odors or visible sources (i.e. mold)?
4. Take air quality measurements. When conduct-
ing a complete IAQ investigation, temperature,
humidity, CO and CO
2
readings should also be
taken to identify problems related to inadequate
and/or contaminated ventilation, potentially
creating a particulate problem. For example,
temperature and humidity readings play a key
role in identifying mold and bacteria. A location
with high relative humidity and higher concen-
trations of particles 3.0 μm or larger may indicate
the presence of mold spores, which should be
remediated once identified. High concentration of
0.3 μm to 10 μm particles may imply presence of
bacteria which may endanger patient in surgery
room or special infirmary.
The most efficient procedure for assessing indoor
air quality is to obtain several outdoor air read-
ings as baselines, noting where the readings are
taken in relation to the facility. At least one of
the readings should be from near the building’s
fresh air intake vent. Note, however, the location
of the intake vent to ensure baseline readings
are not skewed by pollutant sources, for example,
locations near a loading dock. An indoor air par-
ticulate “target” is then calculated by modifying
the baseline readings by the efficiency of indoor
filtering. In the case of cleanroom application, “as
build”, “at rest”, or “operational” (the three stages
of cleanroom) can be used as baseline. But once
the baseline is established, data collected should
always be compared against the “same” baseline.
Particles tend to diffuse very quickly into the
surrounding air, making source identification a
challenging task. One method is to take multiple
indoor readings, starting with the complaint area
first, then move outwards. Get a map of the HVAC
systems, as installed and use that to create an
inspection route. Within each zone, take a mea-
surement in the middle of the space as well as
near the air intakes, outtakes, and any other HVAC
system elements. Make particular note to measure
both upstream and downstream at any HEPA filters.
As data is collected, take note of any unusual
increases in particulate quantity and size. Make
use of the Fluke 985 location naming and data
storage capability to distinguish particle concentra-
tion in different locations for comparison. Compare
the particle readings against the baseline to get
a feel for the relative severity of the particulate
concentration, and identify hotspots and pathways
that may lead to the particulate source. Continue
to follow the path of higher concentrations until
the source is identified. Once the source is remedi-
ated, the area is reassessed to ensure the corrective
action addressed the problem.
Combined with the Fluke 971 Temperature and
Humidity Meter, the technician can also gauge
the temperature and humidity readings against
the accepted parameters (see ASHRAE Standards
55 and 62) for a basic IAQ investigation and take
appropriate steps to treat the problem.