2019 IAQA Annual Meeting
Frank Santini, JD, MBA
Pure Air Controls Services, Inc.
Office: 727-572-4550 ext. 804
Cell: 727-515-2960
Evaluation of Steam Cleaning in
AHU Coil Sanitization and
Energy Efficiency
2019 IAQA Annual Meeting
Acknowledgements
• Alan Wozniak, CIAQP, CIEC
• Dr. Rajiv Sahay, FIAS, CIAQP
• Francisco Aguirre, CIAQP, CIAQC
• Troy Raszka, Communications
Director
2019 IAQA Annual Meeting
Why Clean The Coils?
• ContentKeeping evaporator and condenser coils of an air conditioning
system clean does more to maintain operating efficiency and
increase equipment life than any other preventive maintenance
procedure.
A regularly scheduled coil cleaning will help keep your
equipment running better and longer.
2019 IAQA Annual Meeting
What Conditions Do We Find?
• Content• Dark, Damp, Oftentimes Wet Conditions
• Formations of Endotoxins, Mycotoxins,
Bacteria, Fungi, Pollen, Particulates &
Other Bio-pollutants
• Metal Surfaces & Permeable Materials,
e.g. Fiberglass Insulation
2019 IAQA Annual Meeting
What Bio-contaminants do we find?
Alternaria Aspergillus Cladosporium Curvularia StachybotrysNigrospora
2019 IAQA Annual Meeting
Human Skin Cells
• Content • Bacteria in Air Conditioning
Systems Consume Human Skin
Cells as a Food Source
• Ammonia is a By-product of
Consumption Process
• Body Odor & Urine Smell
2019 IAQA Annual Meeting
“Dirty Sock Syndrome”
• ContentEvaporator coil bio-mass leads to what has been
called “Dirty Sock Syndrome”.
“Medically there is a direct association between
poor indoor air quality in both homes and buildings
and an increase in the prevalence of asthma,
emergency room visits and allergy-type
symptoms.”
- Dr. Janvier Gasana, MD, PHD at Florida International University, Robert Stempel College of
Public Health, Environmental & Occupational Health
2019 IAQA Annual Meeting
Insulating Effect in Fouled
Coils
• Coils Are a Source of Heat Transfer
• Insulating Against Heat Transfer Robs
The System of its Efficiency
• Anything That Contacts Coil Surface
Can Have an Insulating Effect: Dirt,
Grease, Dust, Corrosion, Tobacco
Smoke And, of Course, Microorganisms
2019 IAQA Annual Meeting
A Little Bit of Dirt Makes a BIG Difference
A build up of only 3/16 of
an inch of fouling on the
coils can DECREASE
EFFICIENCY 21%!
The U.S. Environmental Protection Agency
2019 IAQA Annual Meeting
Deferred Maintenance
Deferred Maintenance = Fouled Air Handling Units + Dirty Ducts
2019 IAQA Annual Meeting
Chemical Rinsing
• Is Not a “Green” or Eco-Friendly Process
• Chemicals can Corrode the Interior of Coils
• Chemicals Rinse into the Waster Water
System
• Only Cleans the Surface of the Coils (60 psi)
• Marginally Improves System Performance
• Very Little to no Measurable Energy Savings
• Minimal IAQ Improvements
Note: Clean coils are not necessarily bright. Typically the brighter the coil’s surfaces, the more metal you have just removed.
2019 IAQA Annual Meeting
Why Steam Works: It Removes Pathogens
Heat alone ensures that the
bonding between micro-organisms
and the surface structure is broken
down while the low pressure allows
the steam to deeply penetrate into difficult to reach areas.
2019 IAQA Annual Meeting
Steam Coil Cleaning
• Steam/Particulate Containment Area Set Up
• Coil Cleanliness Verification Test
• HEPA Vacuum Interior of AHU
• Steam up to 350° F and up to 350 psi
• Flush at 55 gal/min to Remove Latent Debris
• Water Extraction Maintained
2019 IAQA Annual Meeting
Steam Coil Cleaning
Coil Cleanliness Verification Testing measures Delta P/Air Flow before & after cleaning.
2019 IAQA Annual Meeting
Steam Coil Cleaning
Steam cleans up to 350° F and up to 350 psi to disinfect/flush the coils.
2019 IAQA Annual Meeting
Importance of Physical Removal
Before Steam Cleaning
• Surfaces Are Left Thoroughly
and Hygienically Deep Cleaned
• Human Skin Cells, Dust,
Debris, All Physically Removed
• Compared to UV Lighting
2019 IAQA Annual Meeting
CABA White Paper: Findings
Parameter
Pre
Treatment
Post
Treatment
% of
Change
Overall
Performance
Microbes
Bacteria (CFU/ml) 154,000 BDL 10099.98% effective
against microbial
contaminantsFungi (CFU/ml) 132,000 60 99.95
Physical
Air Flow (CFM) 250 340 36.00Airflow better by
36.00%
Air Velocity (FPM) 182 250 37.36Air velocity better
by 37.36%
CFU: Colony Forming Unit CFU: Cubic Feet per Minute FPM: Feet per Minute
2019 IAQA Annual Meeting
CABA White Paper: Research
• Field experience and studies show that air conveyance components without proper maintenance become a suitable ecosystem for microbial growth and lead to IAQ problems
• EDLab estimated 368 ft² surface area within an air conditioning coil (17”x 20”x 6.5”,12 fin per inch) that can harbor billions of particulates both biogenic and a-biogenic
• 2.7 Billion CFU/ml/in2 Bacteria
• 2.3 Billion CFU/ml/in2 Fungi (Mold)
2019 IAQA Annual Meeting
Georgia Tech Case Study
Units BeforePURE-Steam
AfterPURE-Steam
ImprovementNET
CFM* 6286 8964 2678 or 42.6%
WC* 0.16 0.126 .034 or 22%
Pa 39.9 31.4 8.40 or 22%
BTU 180,000 270,000 90,000 or 50%
Tons 15 22 7 or 46%
CFM: Cubic Feet per Minute WC: Inches in Water Column Pa: Pascal
BTU: British Thermal Unit *NEBB Reporting
2019 IAQA Annual Meeting
Steam Coil Cleaning Conclusions
IAQ Benefits
• Chemical Free
• Disinfects at 280-350° F
• Eradicates Bacteria & Fungi
• Eliminates Musty Odors
• Improves Fresh Air Exchange
Institutional Benefits
• Optimized Performance
• Reduced Work Orders
• Extended Equipment Life
• Energy Savings
• Energy Rebates
2019 IAQA Annual Meeting
Bibliography
• Sahay, Rajiv, Evaluation of Steam Cleaning in AHU Coil
Sanitization and Energy Conservation, Continental Automated
Buildings Association, IS 2013-28, March 2013.
• The Truth about Steam Cleaning, European Cleaning Journal
http://www.europeancleaningjournal.com/magazine/articles/speci
al-features/the-truth-about-steam-cleaning