Fluke 985 Service Guide

Airborne particle counters
provide vital information for
maintaining indoor air quality
in healthcare facilities

In the highly sensitive environment of a healthcare facility,
where both infectious patients and those highly susceptible
to infection receive treatment, it is essential to minimize the
possibility of infection and disease transmission.

One potential vector of infection
that must be managed is the air
circulating within the building.
Failure to correctly monitor and
manage indoor air quality can
add cost due to increased lengths
of stay, expose the institution to
liability and, more importantly,
expose patients and staff to
unnecessary risk.

In an effective indoor air qual­ity (IAQ) program, a handheld
airborne particle counter such as
the Fluke 983 is an important
tool. Used in conjunction with
pressure and airflow testers, par­ticle traps and laboratory
analysis, the particle counter can
provide facilities managers with
the data they need to detect I
problems, identify and address
root causes and verif
ditions ha
acceptable levels.

enables the healthcare fac
manager to:

•

•

ve retur

ifically, a particle c

Spec

ocument baseline particle

D

ounts w

c
Detect when airborne particu­late levels diverge from
baseline or “normal

ithin a specific space

y when c

ned to

ounter
ility

” levels

Technology
at Work

Gain early warning of underly-

•

ing issues, such as changes
in operating procedures,
equipment malfunctions,
maintenance shortcomings or
failure to separate construction
zones from patient areas
Test particle levels after

•

changes have been made, to
ensure that remedies have
been effective

The use of handheld test instru­ments has received endorsement
at the highest levels. According
to infection control guidelines
published by the U.S. Centers for
Disease Control in 2003, “the use
of handheld, calibrated equipment
that can provide a numerical

AQ

reading on a daily basis is pre­ferred for engineering purposes”

-

on

in ensuring the proper and safe
operation of HVAC systems.

It must be clearly stated, how­ever, that the particle c
not designed to determine what
particles consist of or whether
the particles c
threat of infection. Those judg­ments must be based on

orator

lab
samples collected in the health­care facility and cultured in a

orator

lab

ounted pose a

y analysis of particle

y setting.

i

ounter is

From the Fluke Digital Library @ www.fluke.com/library

Sources of IAQ Problems in Healthcare Facilities

The spread of infection through the indoor air is a serious
potential problem in healthcare facilities. Such infections
can stem from two sources:

• Infectious agents produced by people inside the facility,
such as Tuberculosis, Rubella (measles) and influenza

• Agents normally present in the human environment that
can endanger patients who have compromised
immune systems. Such organisms include

fumigatus

Other airb
as inorganic materials and aller
gens, while capable of causing
health problems, pose a lesser
threat to patients. These contami­nants will not be addressed in
this document, though the air fil­tration and air pressure balancing
techniques that help control bio­logical pathogens can also control
odors, dust and other non-viable
air pollutants.

To control the movement and
spread of infectious agents, facil­ity designers and managers
establish special purpose spaces
called Airborne Infection Isolation
(AII) or patient isolation room,
and Protective Environment (PE)
facilities. In both of these special
ventilation spaces, air pressures

ulated to move air from

are reg
clean to dirty areas.

The AII room would house a
patient judged to b

ne infection, such as

or

airb
Mycobacterium tuberculosis or
measles v
from the room and exhaust it out
side the building. High efficiency
particulate air (H

, a common species of mold, and others.

e used to help remove particles

orne particulates, such

b
from the air

­into the room is balanced so that
the room remains under negative
air pressure. Thus the direction of
airflow under the door or when
the door is opened is
space, rather than out, helping
contain infectious particles.

The Protective Environment
facility is designed to keep infec­tious agents out and protect
immuno-suppressed patients and
others, such as bone-marrow and
organ-transplant patients and
premature infants, who are espe­cially vulnerable to opportunistic
infectious agents. The CDC
ommends that PE facilities be
maintained under positive air
pressure, with directional airflow
(from one side of the room, across
the patient to the exhaust) and
twelve or more air changes per

e a sourc

e of

. Clean air is supplied

hour
through H

E

of-use HEPA filters may also be

irus

. V

ents draw air

-

. Air flow

used
open door or leak moves out of
the space, not in.

A) filters ma

P

E

y

Aspergillus

. Makeup air flowing

into the

ii

rec-

PA filters, and point-

ing through an

2 Fluke Corporation Airborne particle counters provide vital information for maintaining indoor air quality in healthcare facilities

Sources of IAQ Problems

AII and PE facilities provide a framework for limiting the
spread of infectious agents, but they are not foolproof.
Building design, inconsistent or inadequate operating
procedures, poor maintenance and facilities construction
and renovation projects all have the potential to cause
problems. And in any case, protective facilities are not
used for all patients.

Even the b
airflow desig

est air filtration and

n can be defeated

by inadequate maintenance or

orrect operation. A slipping

inc
fan belt on a ventilation supply
fan, for instance, could alter
the air balance in a protective
environment facility, allowing
particle-laden air from the hall­way outside to flow in. Failure to
correctly seal off and ventilate a
construction area can send a
cloud of construction dust and
Aspergillus spores into areas
where patients are housed.
Failure to fix a leaking sink can
turn the cabinet below into a
nursery for potentially hazardous
mold.

Andrew Streifel, MPH, hospital
environment specialist at the
University of Minnesota, recalls
what happened when cost­conscious hospital administrators

ned off the fan ventilating the

tur

e over a dropped c

spac

eiling in
an intensive care area. “That
allowed humidity to stag

. “When humidity reached

ys

sa

nate,” he

extremely high levels in the
Minnesota summer, it started

U. The water

raining in the I

C

was coming through the ceiling

rid and dripping on the patients

g
They stopped using four or five of
the intensive care rooms, and
diverted patients

oncern, Streifel continues, was

c

.” The larger

the possibility that the high
humidity would permit mold

rowth. Raising the room

g

temperature ab

ided a temporar

prov
stopped the “rain.”

Building c

renovation can pose particular

.

challenges. Disruption to the
building
of large amounts of c

ove the dewpoint

y fix, and

iii

onstruction and

’s envelope, generation

onstruction
dust and debris and the move­ment of workers and equipment
in and out of c

ontainment zones

all present contamination threats

eyond the norm for a healthcare

b

ility

fac

ent asperg

rec

ording to the CD

c

. Ac

illosis outbreak

C, “a

among oncology patients was
attributed to depressurization of

CT

the building housing the H

S

unit while construction was

y in an adjac

wa

under

. Unfiltered outdoor air flowed

ing

ent build

into the building through doors

s, exposing patients

indow

and w
in the H

SCT unit to fungal spores.

-

iv

3 Fluke Corporation Airborne particle counters provide vital information for maintaining indoor air quality in healthcare facilities

Contamination Testing with Airborne Particle Counters

When such problems occur, an airborne particle counter
such as the Fluke 983 can help hospital staff and industrial
hygienists detect increased particle levels, identify the
sources and verify the effectiveness of remedial action.

The Fluke 983 Particle Counter
operates by pumping an air sam­ple of known volume—generally
one liter—past a laser beam. As
dust particles in the air stream
pass through the beam, each one
reflects or “scatters

. A photodetector senses the

light
scattered light and generates an
analog electrical signal. Larger
particles scatter more light and
create higher-voltage electronic
“hits.” Onboard electronics track
the hits and count the particles in
six size categories, ranging from
.3 microns to 10 microns.
Particles larger than 10 microns
generally settle out of the air.

The Fluke 983 can be pro­grammed to take repeat counts
instantly, or delayed up to 24
hours between samples. It can
store 5000 records of date, time,
counts, relative humidity, temper­ature, sample volumes, alarms
and location label records in its
onboard memory. Stored readings

y then b

ma
personal c
tive, the particle counter can be

onnected directly to a P

c
time dow

According to the CDC,

articulate sampling (i

“P
numb
ulates) is a practical method for
evaluating the infection-c
performanc
with an emphasis on filter effi-

ienc

c
particles (< 5
larger particles from the air.”

The ac

ompact size of the Fluke 983

c
make it useful for baseline partic­ulate testing, problem detection
and remediation and system
maintenance.

e dow

omputer

nloads

ers and size range of partic

e of the H

y in remov

curac

” the laser

nloaded to a

. As an alter

.

.e., total

VAC system,

ing respirable

µm in diameter) or

y, speed and

na-

C for real

ontrol

v

Baseline Testing. To know

•

when the “abnormal” occurs,
it’s necessary to document
what are normal levels of par­ticles. According to Andrew
Streifel, it’s not reasonable to
expect “clean room” conditions
in a healthcare setting. When
staff rush into a room to inter­vene in a patient emergency,
there’s no time to worry about
air quality. Particle counts will
soar with the presence of mul­tiple people (human beings
shed some 500,000 particles
each minute) and medical pro­cedures too can contaminate
the air. But later, counts should
return to normal or baseline
levels. Best practice calls for
baseline particulate levels to
be documented, both within
spaces and in the supply air
flowing into the space.
Maintenance Testing. Once

•

baseline or “normal” particle
levels are determined,
followup tests should be
performed and documented
periodically. These followup
tests can provide early warn­ing of developing anomalies
and enable the facility
manager to intervene before

-

anyone gets sick.
Filter Testing. Used to test for

•

particle levels in the air
upstream and downstream
from filter media, the Fluke
983 can verify that filters are
performing as they should.
Testing the level of particles
in incoming filtered air at the
diffuser (air grate)—air that
should be the cleanest in the
room—provides an additional
check on the performance of
filtration systems.

Writing in HPAC Engineering

magazine, Streifel said “when
dealing with filtration testing,
the verification data should
be reflected with objective
analysis by providing
airborne-particle comparison
with the specifications of filter
efficiency for fan systems. The
objective analysis available

y should provide function-

toda
ing pressure gauges,
inspection information of the
filter bank
particle analysis of filters for
filtration leaks. The particle­analysis procedures at this
time are not standardized but
yet the comparison of before
versus after filter tests with
atmospheric dust particle
sizing will help to assure that
the 90-percent-efficient filter
is removing 90 percent of the
particles greater than 0.5 µm.”

Locating Particle Sources.

•

The Fluke 983 can help
identify areas where particle
counts are elevated and,
ultimately, lead the user to
the source. A leaking air duct
could be sending unfiltered
air into a room, for instance;
work ab
ceiling could be disturbing
accumulated dust.

erify

V

•

of R

causes of higher particle

ounts ha

c
post-testing w
whether the fixes employed

ve really worked at bring

ha
particulate levels dow

Controlling airborne contamina­tion within healthcare facilities
poses a complex set of challenges
far beyond the scope of this
paper. Numerous additional
resources are available to help
the professional understand and
overcome those challenges.
Among those easiest to grasp is
the Fluke 983 handheld airborne
particle counter.

s, and objective

ove a suspended

ing the Eff

emediation

een addressed,

ve b

ill show

ectiveness

.

e the

Onc

.

n

ing

vi

4 Fluke Corporation Airborne particle counters provide vital information for maintaining indoor air quality in healthcare facilities

i Guidelines for Environmental Infection Control in Health-Care

Facilities, Recommendations of CDC and the Healthcare Infection
Control Practices Advisory Committee (HICPAC), U.S. Department of
Health and Human Services Centers for Disease Control and

Prevention (CDC), 2003, page 20.
ii Ibid, page 34
iii Interview with Andrew Streifel, April 22, 2005
iv Ibid, page 26
v Ibid, page 27
vi “Hospital Accreditation for Airborne Infection Control,” by Andrew

J. Streifel, MPH,

HPAC Enginering, March 2003, page 49.

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