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Application Note

Indoor air quality

monitoring made easy

with the Fluke 985 Particle Counter

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

Why particle counts matter

Different locations have varying levels of accept-

able particulate concentrations. In a residential

and commercial environment (i.e. homes, offices,

hotels), health and comfort concerns and fear for

litigation often drive IAQ investigations. In indus-

trial and institutional environment (hospitals,

food and beverage plant, electronic and precision

manufacturing), energy cost, contamination control

and production yields are the primary concern.

Excessive levels can result in medical conditions

such as Sick Building Syndrome, lower productivity,

contaminated product, or all of the above.

Maintaining acceptable air quality levels not

only lower the costs associated with downtime, but

also reduce or remove costs associated with expen-

sive fixes in the future. The first step in establishing

an IAQ maintenance program is to determine if a

problem currently exists.

Introduction

Energy savings is top of facilities owners

agenda. HVAC system tends to be the

largest contributor to energy bill. Tax

rebates are often based on energy savings

per square footage. But savings on HVAC

energy costs can cause significant IAQ

issues due to improper ventilation, temper-

ature and humidity control. Leaving system

off until occupants arrive in the morning

might save money, but allow pollutants to

build up in the air. If HVAC system is not

properly maintained and air filter checked,

it could guarantee IAQ problems. The

effects of indoor air quality (IAQ) has been

highlighted in numerous environment risk

reports and joint agency efforts by the U.S.

Environmental Protection Agency (EPA).

Further studies indicate that indoor air in

some commercial buildings is up to five

times more polluted than outdoor air.

Airborne particulates come in a variety

of forms ranging from animal dander, plant

pollen, and airborne bacteria, to fiberglass,

asbestos, and combustion particles that

are generated from part of the production

equipment or process. To properly iden-

tify and troubleshoot IAQ problems, the

technician needs a tool that not only reads

particle concentrations for spot check, but

also provides continuous monitoring for

process control.

Summary of content (6 pages)

PAGE 1
Indoor air quality monitoring made easy with the Fluke 985 Particle Counter Application Note Introduction Energy savings is top of facilities owners agenda. HVAC system tends to be the largest contributor to energy bill. Tax rebates are often based on energy savings per square footage. But savings on HVAC energy costs can cause significant IAQ issues due to improper ventilation, temperature and humidity control.
PAGE 2
IAQ investigation of cleanroom) can be used as baseline. But once the baseline is established, data collected should An IAQ investigation is the first step in an ongoing always be compared against the “same” baseline. maintenance program or in responding to comParticles tend to diffuse very quickly into the plaints potentially associated with air quality. No surrounding air, making source identification a matter it is commercial/residential or industrial/ challenging task.
PAGE 3
Interpreting the data A correct interpretation of the data requires an understanding of the test area. Is the area residential or commercial? Is it cleanroom or precision manufacturing area? Is the cleanroom “at rest” or “operational”? Is the location exposed to tobacco smoke or combustible particles? Is there construction at or near the location? A proper assessment of the environment can help narrow down the list of problem particulates.
PAGE 4
Table 1. A cleanroom exercise (certification and monitoring) Cleanrooms are an excellent application for a particle counter. Certification for cleanrooms is usually conducted at “as build” stage. For illustration purposes, let’s put the Fluke 985 to the test in evaluating an ISO Class 5 (per ISO 14644) cleanroom. To qualify as a Class 5 cleanroom, levels cannot exceed the limits for the class in each particle size stated in the following table: Our test is concerned with the concentration of 0.
PAGE 5
The individual readings are well within the limitations for the cleanroom; however, we can take the following steps to determine the statistical validity of the readings: Step 1: Calculate the mean average particulate concentration M = (AC1 + AC2 + AC3+ AC4+ AC5+ AC6) / L 995 = (674 + 1154 + 1097 + 841 + 828 + 1376) / 6 Step 2: Calculate the standard deviation of the averages SD = ( (AC1-M)2 + … + (AC6-M)2) / (L-1) 116 = ( (674-995)2 + (1154-995)2 + (1097-995)2 + (841-995)2 + (828-995)2 + (1376-995)2) / (6
PAGE 6
Making sense of particle counter features Using a particle counter is relatively simple; however, understanding the features that distinguish counters can sometimes be a challenge. The following terms are commonly used to describe the accuracy, efficiency, and other attributes of an airborne particle counter. Count Mode: The count mode defines how the particle counter displays data to the user. Concentration and Raw Count are two typical sampling modes, and the Fluke 985 adds an Audio mode.