Whittaker Powerpoint June 08
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Transcript of Whittaker Powerpoint June 08
Applications of the Opticle Particle Counter in an IAQ
Assessment
Columbia SC Chapter IAQA Workshop June 26, 2008
Presented by:
Craig Whittaker, CIE, Ph.D. Environmental Solutions Group
Brief History of the Particle Counter
Parallels the development of the personal computer
First developed in the 50s to monitor dust in manufacturing
Evolved into a tool for assessing clean rooms
Greatest design advances made in last few years
The IAQ professional now
has several options for small,
powerful and intuitive devices that offer real-
time data logging & other features
Most airborne particles are either biological contaminants, gases or dust
Handheld particle counters today are well-equipped for measuring airborne biological contamination
Current Technology
Biological contaminants include: Mold Dust mites Viruses Animal dander Bacteria Pollen Skin fragments Insect parts
Recent Studies on the Health Effects of Fine Airborne Particles
European study found that fine particles that are inhaled can affect the blood vessels, leading to an increased risk of heart disease - American Journal of Respiratory and Critical Care Medicine
Children with asthma had significantly decreased lung function following exposure to indoor air pollution that included fine airborne particles - National Institute of Allergy and Infectious Diseases
How Does the Particle Counter Work?
Counts particles
that block a beam of light reflecting
onto a screen QuickTime™ and aGIF decompressor
are needed to see this picture.
The three components of a particle counter:
1) airflow system
2) optical system
3) electronics
The Airflow System
Includes an isokinetic probe, air chamber and pump
Its job is to capture a sample of moving air at the same velocity it is moving, allowing a normalized count
The Optical System
Includes a high-grade laser, optical measuring components and a
detection surface (screen)
Its job is to measure the scattered light against the screen
The Electronics
Includes computerized amplification and counting circuitry
Its job is to amplify the low level signals from the detector surface and convert each scattered light pulse to a number
representing its corresponding size
Tabletop vs. Portable Unit
Tabletop unit has a larger pump and can attach to multiple sensors throughout an area for continuous monitoring of clean rooms
Portable unit is designed for point-of-use measurements in critical locations to include clean rooms, medical facilities and HVAC systems analysis in commercial & residential buildings
One of the most useful aspects of the portable unit is the ability to track
contamination - everything from
fine dust to biologicals - to the
source
One of the most common applications of the portable unit is for
measuring the efficiency of
filtration systems
Limitations of the Laser Particle Counter
Refracted light varies due to differences in particle shape & shininess
Particles are not always evenly distributed throughout a room
The electronics employ a bell-curve (Gaussian) distribution method of categorizing particle sizes
Guidelines for Use
Store unit at room temperature in a vibration-free environment
Keep unit clean per manufacturer’s instructions
Stay clear of electrical equipment while collecting readings
Consider keeping a log of preventive maintenance, recalibrations and any unusual performance
Application: Trend Analysis
Noting gradual or sudden changes in airborne contamination when an HVAC system is powered
on/off1
Establish baseline readings prior to a process that may change the indoor air environment
Monitoring filter efficiency by sampling air immediately before entering & after entering the filter
1NADCA’s ACR 2006 contains particle profiling procedures for HVAC systems
The single most important advantage of the handheld particle counter is the
ability to conveniently collect multiple readings in an area to generate a
statistically valid sample based on the average particle counts for the area.
Case Study #1: Outpatient Surgical Center
Two operating rooms and sterilization and surgical preparatory rooms flooded with clean water over
a weekend. Water soaked floors and drywall.
Our firm arrived immediately after standing water was extracted to collect baseline (first-response) airborne particle readings prior to installation of
HEPA air scrubbers.
Safety was of primary importance to the client but speed of remediation
was also crucial. The remediation and
reconstruction had to be complete and post-
remediation verification obtained in only 48 hours
Handheld particle counters were used extensively to monitor the effectiveness
of air scrubbers
Particle counts were recorded at entering and exiting points of twelve air scrubbers
Scrubber positions were adjusted frequently to
address ‘hot spots’ where counts had
spiked
Every phase of the project was guided in part by the particle
readings
The remediation was completed ahead of
schedule and particle counts were excellent.
All that remained to be installed was the
new flooring.
The ‘sterile’ vinyl arrived in the back of
a filthy truck
Particle counts jumped nearly 7000% in the
operating rooms upon bringing the vinyl into
the rooms
The floors were finished at midnight with the rooms scheduled to
open at 7:00 am.
We logged airborne particle counts until
5:30 am; counts were low enough to indicate a successful clearance
Spore counts were collected for lab analysis in one hand while re-
checking particle counts in the other
hand
Rush analysis by a local lab confirmed that no fungal spores were present
in the operating suite.
Surgeries were performed on schedule and the client was relieved
Case Study #2: Physician’s Residence
A medical doctor who recently purchased a 100-year-old home on the NC coast had experienced flu-like symptoms since moving in two months
ago
His wife and child have no symptoms, but they sometimes noticed a musty odor on the main
level
A visual assessment yielded no moist building materials or fungal growth inside the home
Airborne particle counts were abnormally high in the 2.5-µm classification
in the kitchen. After ruling out food items as the source, we collected a particle reading in a
base cabinet and found the 2.5 -µm count to be 700% higher than the average count for that size particle elsewhere
in the house
0500
1000150020002500
Avg. PC's in2.5-micronsize zone
Out ofkitchenInkitchenIncabinets
The culprit appeared to be gold-colored
material on an exterior plaster wall in a base
cabinet where cooking items were stored. We removed several items to expose the material
for sampling & for taking this picture.
Lab analysis indicated an elevated count of 2320 aspergillus/penicillium spores/m3 in the total spore
count. An air culture indicated a count of 320 cfu/m3 of aspergillus.
The physician/homeowner was subsequently tested and found to have a fungal infection in his digestive tract. Remediation and antibiotics have resolved his
medical issue.
Case Study #3: Office Building
An employee at a call center that had experienced a water leak from the HVAC system one year ago
was taken to the hospital after cleaning under her desk. She developed a severe rash on her
arms & was having trouble breathing.
The employee told us that the carpet under her desk remained wet for a few days following the
leak incident of a year ago
Particle counts were collected in thirty locations throughout the 10,000 SF building. Ambient readings and readings at air supplies were
collected.
Particle counts were normal for the building in all areas except near the affected employee’s desk,
averaging 1167 count in the 1.0 to 10.0-µm classifications. Readings near the desk averaged
1483.
After slightly agitating the
carpet under the employee’s desk, particle readings
jumped over 300% from 1483 to 4619 in the 1.0 - 10.0 µm
classifications.
010002000300040005000
Avg. PC's in1.0 - 10.0microns
Office-wideAt desk
Agitated
Lab analysis indicated an elevated presence of aspergillus/penicillium in a sample of the carpet
and an elevated count of 1320 aspergillus/penicillium spores/m3 in the total
spore count collection from under the desk. An air culture indicated a count of 271 cfu/m3 of
penicillium. The employee is allergic to penicillin and her doctor believes that her immune system had a reaction to the spores released from the carpet
during vacuuming. The carpet was replaced and the area cleaned and
the employee has had no further issues.
Case Study #4: Three Crawl Spaces
Examines the relationship between room particulate counts in residences with crawl spaces with some areas of visible fungal
contamination.
Question: is there a correlation between elevated airborne particle counts in an area with no visible contamination and an adjacent but hidden area
with visible contamination such as in a crawl space?
Conclusion
Based on somewhat limited data, the opticle particle counter appears to provide the IAQ
investigator who is assessing an apparently clean area with information
that relates to fungal contamination in an adjacent but hidden contaminated area.
Data Set from 21 Locations
A collection of pre- and post-remedial readings from residential, office and
medical buildings
Criteria for inclusion:Our firm performed the assessments
The identical calibrated equipment was used for data collection
Lab analysis was performed by the same labData is less than one year old
Total Countsn = 21
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
Total Counts
Raw Counts
PC Initial SpT Initial Cult Initial PC PRV SpT PRV Cult PRV
Averaged Countsn = 21
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Averaged Counts
PC Initial SpT Initial Cult Initial PC PRV SpT PRV Cult PRV
Conclusion
The opticle particle counter provides the IAQ investigator with a convenient means to
gather a substantial amount of reliable, real-time data relating to air quality. It is a valuable
addition to the IAQ investigator’s toolkit.
More research is needed, however, to determine how the data is to be
interpreted.
Additional Research Areas
What role does the environmental condition play?
DampnessBarometric Pressure
Building PressurizationTemperature
Selection of a Particle Counter
• Define the intended use of the device - will you be assessing cleanrooms or ‘dirty’ areas (or both?)
• Decide on the features you require - will you be storing large amounts of data, assessing for certain particle sizes, printing readings on site, or downloading data into a computer?
• How easy is the unit to use? Can it survive a fall or extreme conditions? Does it have a touch-screen interface? Can it record temperature & humidity readings in addition to particle sizes and mass concentration?
• You may want to try renting a unit prior to making a purchase so you don’t make a mistake (these devices start around $2000)
ISO 14664-1 Cleanroom Standards
0.1 µm 0.2 µm 0.3 µm 0.5 µm 1 µm 5 µm
ISO 1 10 2
ISO 2 100 24 10 4
ISO 3 1,000 237 102 35 8
ISO 4 10,000 2,370 1,020 352 83
ISO 5 100,000 23,700 10,020 3.520 832 29
ISO 6 1,000,000 237,000 102,000 35,200 8,320 293
ISO 7 352,000 83,200 2,930
ISO 8 3,520,000 832,000 29,300
ISO 9 35,200,000 8,320,000 293,000
Selected Resources
American Industrial Hygiene Association, Assessment, Remediation, and Post-Remediation Verification of Mold in Buildings (2004)
National Air Duct Cleaners Association, Assessment, Cleaning and Restoration of HVAC Systems (ACR 2006)
Hollace S. Bailey, Fungal Contamination: A Manual for Investigation, Remediation and Control (2005)
Particle Measuring Systems, Counting Efficiency and Resolution in Optical Particle Counters (2007)
Authors
Craig Whittaker, Ph.D., CIE Environmental Solutions Group
Steven Armstrong, M.S., P.G. Environmental Solutions Group
Thank you for attending!Are there any questions?