Inside this issue:
Mechanical Cleaning Methodology:
The HVAC system must be cleaned using mechanical
Cleaning methods designed to dislodge and extract
contaminants from within the HVAC system
components. Mechanical cleaning techniques employ
sizeable vacuum collection units, portable vacuum
collection units, mechanical agitation systems, hand
brushing tools, pressurized air sources, pressurized
water sources, plus other tools and equipment to
dislodge attached particulate and debris and convey it to
a collection device in a safe and controlled manner.
Coil Surface Cleaning:
It is Highly Recommended that all portions of each coil
assembly be cleaned. Both upstream and downstream
sides of each coil section must be accessed for cleaning.
Where limited access is provided between close
proximity or zero-tolerance heating coils in an AHU,
cleaning may require removal and/or replacement.
Coil Inspection and Cleaning Process:
For the purposes of this standard a coil is defined as an
evaporator, chilled water, hydronic, steam, hot gas or
heat pipe which is located within the air stream of an
HVAC system for the purposes of indoor environmental
The process begins with an inspection. The substances
deposited on the coil help determine the initial selection
of the cleaning protocol. There are two (2) categories of
coil cleaning. Coil reconditioning will utilize Type–1 or
Type-2 cleaning methods. Both Types require usage of
HEPA filtered negative air machines when exhausting
within an occupied space. HEPA filters are
recommended, but not required, when machines are
exhausted outside of building.
Negative air machines must be operated continuously
during the complete coil reconditioning process. The coil
must be physically isolated from the duct system during
the cleaning process to ensure disrupted particulate
does not migrate to or redeposit on unintended areas.
Type 1 Coil Cleaning:
Type 1 methods of coil cleaning are appropriate for
removing loose dust, dirt or debris collected upon
evaporator coil surfaces. Physical removal of debris is
accomplished through a variety of methods which may
• HEPA filtered contact vacuuming the coil surfaces
with a vacuum capable of generating a minimum of –
40 inches water lift. HEPA filtered contact
vacuuming must be used in conjunction with the
evaporator coil being maintained with a negative
pressure differential to the general work
• Contact vacuuming may require the use of crevice
tools and brushes.
• Brushes may be used for penetrating between coil
fins and up to the first row of refrigerant tubes
without damaging the fins.
• Compressed air accelerator guns and wands may
be used to dislodge debris embedded between the
evaporator coil fins without damaging the fins.
• Evaporator fin combs and fin straightening tools
designed to restore the evaporator coil fins after
Type 2 Coil Cleaning:
Type 2 cleaning methods are appropriate for removing
adhered debris on all coil, drain pan and drain line
surfaces. Type 2 cleaning should be performed after
non-adhered particulate has been removed using Type 1
methods. Type 2 cleaning may include the following
• All methods under Type 1
• It is not always possible to remove all motors and
electrical equipment from the coil area. However, it
is always possible to either remove, isolate and/or
protect electrical equipment.
• Application of coil cleaning products. (Must be used
in accordance with the manufacturer’s product
• Usage of electric chemical coil cleaner application
• Usage of water washing at normal water line
Remediation of Mold and Other Biological
This section defines processes for remediating mold and
other biological contamination within an HVAC system.
It is highly recommended the remediation plan for mold
decontamination include removal of contaminated
materials or employ aggressive cleaning techniques
when removal is impractical. Removal of contaminated
porous HVAC system materials is recommended (See
ACGIH Bioaerosols: Assessment and Control, 1999).
8.1 Cleaning Methods
Surface cleaning must be performed using mechanical
agitation methods to remove particulate, debris, nutrient
sources and surface contamination. Mechanically
cleaned surfaces must be capable of passing
cleanliness verification methods as defined in this
standard (See Section 13).
8.2 Removal of Mold Contaminated Porous
It is highly recommended that porous materials with
actual fungal growth (Condition 3) be removed. The
exposed non-porous substrate underneath the porous
materials must be mechanically cleaned and treated
before new replacement material is installed.
When removal of all Condition 3 contaminated porous
material cannot be performed, partial removal to the
greatest extent possible should take place. This must be
followed by surface cleaning of remaining material using
mechanical cleaning methods.
Hope everyone has a safe and wonderful week! Check out our website for our weekly specials. We also run our specials on our Facebook page. Thanks again everyone and don’t forget to get your chimney inspected BEFORE you burn!
Aardvark Residential and Commercial Services Inc.