Aurora Public Schools
Standard Operating Procedures
for Stormwater Management
Coil Cleaning
Summary
This work practice covers the procedure for Coil Cleaning set-up and discharge of waste water.
Examples
The following are examples of work that can be performed using this procedure. If job
conditions vary from the examples, stop work and notify the Environmental Compliance Branch.
A.
B.
C.
D.
E.
F.
Pre-planning
Site Visit
Drain Location for discharge
Cleaning Inside Coils – Evaporator Coils
Cleaning Outside Coils – Condensing Coils
Cleaning Re-heat Coils – In ductwork, fan-powered boxes, and VAV boxes
Related Work Practices
A.
B.
C.
D.
E.
F.
G.
Catch basin set up for little to no spillage of waste water to roof or ground
Collection and Release to Sanitary Sewer (Requires Prior Metro Wastewater Approval)
Drainage to Vegetation – No Chemical Used, State Permit required – see Work Practice
Evaporation in Place – No Chemical Used, clean up of residuals – see Work Practice
PPE – Safety Glasses and Nitrile Gloves
Application of Cal-Shield Teflon
Application of Bio-Fresh
Regulatory Information
A State Stormwater Permit is not required for this procedure, however, prior notification and
approval to Metro Wastewater is required. The Environmental Compliance Branch must be
notified at least two weeks prior to coil cleaning activities in order to obtain appropriate
approval.
Worker Recommendation
At least two workers will be required for this procedure. Both workers are to set up a catch basin
for containing the water and chemical mix. One worker will spray the coil from the top side of
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Aurora Public Schools
Standard Operating Procedures
for Stormwater Management
Coil Cleaning
the unit while the other worker monitors the flow into the basin. The worker on the ground or
roof is also in charge of neutralization and pH monitoring prior to pumping the water to the
sanitary drain.
Notes
During the entire coil cleaning procedure, there will be an environmental technician onsite unless
prior approval is given by the Environmental Compliance Branch. The environmental technician
will oversee the project and gather information regarding the units and amount of water and
chemical used.
Coil Cleaning Chemical Flow Chart
Coil Type
Condensing
Dirty
Moderate
Nu-Brite (Purple)
& Cal-Shield
(Teflon)
Clean
Cal-Brite (Pink) &
Cal-Shield (Teflon)
Rinse with water
& Cal-Shield
(Teflon)
Evaporator
Dirty
Clean
Moderate
Cal-Brite (Pink)
Evap Pow’r C
Rinse with water
Rinse with water
Cal-Brite (Pink)
Evap Pow’r C(Green)
& Cal-Shield
& Cal& Cal-Shield
(Teflon)(Green)
Shield (Teflon)
(Teflon)
Re-Heat
Dirty
Moderate
Clean
Cal-Brite (Pink)
Cal-Brite (Pink) &
Rinse with 2water &
Cal-Brite (Pink)
Evap Pow’r CCal-Shield (Teflon)Rinse with Cal-Shield
water
2/7/2016 12:11 AM
& Cal-Shield
(Teflon)
(Green)
(Teflon)
& Evap
Cal-Shield
(Teflon)
Pow’r
C
(Green) & CalShield (Teflon)
Aurora Public Schools
Standard Operating Procedures
for Stormwater Management
Coil Cleaning
Work Practice
A.
B.
C.
D.
E.
F.
G.
Aurora Public Schools’ approved chemicals for cleaning coils are: Nu-Calgon Evap
Pow’r-C, Nu-Brite, Cal-Brite, Cal-Shield, and Bio-Fresh cd.
The only approved chemicals for re-heat and evaporative coils inside occupied buildings
are Evap Pow’r-C and Cal-Brite.
Recommended dilution ratios for all approved cleaning products is 3:1 – 3 parts water to
1 part chemical. This is setting “A’ on the coil cleaning gun.
Set-up will be site specific but needs to include a procedure to capture all water and
discharge to be pH tested and diluted, if necessary, before being discharged to the sanitary
sewer. This can include draping of polyurethane to create a catch basin, 55 gallon drums,
and berms for water collection. The site needs to be inspected prior to beginning any
work to determine the location of storm drains in the area. These areas need to be
protected in the event of accidental discharges.
Procedure
a. Wear appropriate personal protection equipment. Read MSDS for specific
requirements. Avoid contact with skin and clothing.
b. Pre-clean heavily soiled coils with brush or vacuum if needed.
c. Set appropriate dilution ratio on coil gun.
d. Liberally apply coil cleaning solution to coil. Allow cleaner to sit: Alka-Brite and
Nu-Brite for 1-2 minutes, Cal-Brite for 5-10 minutes.
e. Rinse coil with water 2-3 times or as needed. Turn on fans for 5-10 minutes.
f. Apply Cal-Shield teflon coating.
g. In the event that insulation gets wet, apply Bio-Fresh to prevent mold growth.
Neutralization – pH must be adjusted to between 5 and 9 before entering the sanitary
sewer. The Environmental Compliance Branch has a pH meter that can be used to
monitor the pH. pH can be adjusted using vinegar or baking soda depending on the pH of
chemical used. pH must be monitored continuously throughout the procedure.
Disposal
a. Sanitary Sewer: Once pH is in the appropriate range, the waste water can be
pumped to the sanitary sewer.
b. Evaporation in Place: If using evaporation in place, NO chemical can be used.
Complete evaporation must take place before water reaches any storm sewer
system or conveyance and all residuals must be cleaned.
c. If sanitary sewer or evaporation in place is not an option, please contact the
Environmental Compliance Branch for alternative disposal methods. Discharge to
vegetation requires a permit and MUST be approved prior to use.
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Aurora Public Schools
Standard Operating Procedures
for Stormwater Management
Coil Cleaning
H.
I.
Documentation – The HVAC technician must complete the “Aurora Public Schools Coil
Cleaning Record Keeping” form for EVERY unit cleaned. The information on this form
must include the site and unit being cleaned, the chemical used, where the discharge
occurred, and the amount of both water and chemical used. Copies of this form are
available from the Environmental Compliance Branch.
Prohibited activities
a. Do not perform procedure in windy conditions.
b. No discharge is allowed to enter the storm drain system.
c. Be aware of possible leaks entering building during the entire procedure.
Discharge Regulatory Flow Chart
Are you
using
Chemical?
No
Yes
Discharge to
Sanitary
Sewer (Must
have prior
approval from
Metro
Wastewater)
Discharge to
Sanitary
Sewer (Must
have prior
approval from
Metro
Wastewater)
Neutralize to
pH of 5-9
Evaporate in
Place
Neutralize to
pH of 5-9
Clean up all
residuals
Discharge to
Storm Sewer
System (Must
obtain State
and City
Permits)
Discharge to
Vegetation
(Must obtain
State and City
Permits)
Must get
special
approval
Must get
special
approval
before using
before using
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