Summary of Ventilation Cleaning Program
July 2002
Written by Tom Fusillo (Environ Co.) in consultation with Howard Bader (H.A.
Bader Consultants, Inc.) Air-handling equipment to be cleaned includes
floor-mounted unit ventilators, ceiling-mounted unit ventilators and the
central heating, ventilation and air-conditioning (HVAC) system. In
addition, carpeting in the auditorium and office is to be removed and
upholstery cleaned. These protocols will evolve as work progresses.
Floor-Mounted Unit Ventilators
Floor-mounted unit ventilators are first removed from the wall by
disconnecting the hot and chilled water distribution system, draining and
collecting the ethylene glycol solution from inside the chilled/hot water
coil, and disconnecting the electrical power. The removed unit ventilators
are sealed inside a plastic enclosure, which is kept at negative pressure
during cleaning of the unit in order to contain the dust from the unit.
The unit ventilator front panel is removed to allow access to the unit. The
existing filter is removed from each unit and the insulation inside the
front and rear panels is removed as is insulation inside the air handling
portion of the unit. The heating/cooling coil and supply fan blades are
cleaned using a low volume water cleaning system. All portions of the unit
are HEPA vacuumed, and wiped clean and dry. All areas made accessible by
the removal of the unit are also cleaned, including the exterior louvers and
the area beneath the unit. Insulation inside the electrical compartment of
the unit is HEPA vacuumed and coated with an encapsulating paint. After
cleaning, the unit is inspected for residual dust. If the unit is judged
clean based on inspection, one wipe sample for analysis of lead is collected
from the inside of the unit. If the wipe sample passes (that is, it
contains less than 20 micrograms per square foot of lead), the unit has new
insulation and filter installed, is reassembled and wrapped in plastic. If
the wipe sample fails (above 20 micrograms per square foot), the unit is
re-cleaned and resettled until it passes both a visual inspection and wipe
testing. After all the units in a room are cleaned and pass the visual
inspection and wipe testing, the unit ventilators are reconnected and
reinstalled and covered with plastic sheeting. Then a general cleaning is
performed in the room and two wipe samples are collected from horizontal
surfaces in the room. If room surface samples pass (lead concentrations
less than 20 micrograms per square foot), then the plastic is removed from
the units and the room is completed. If room surface samples fail, then the
room would be re-cleaned and retested until satisfactory test results were
obtained. In addition to inspections being made by the School Construction
Authority and its contractors, the cleaning of the unit ventilators is also
inspected by a consultant to the Stuyvesant High School Parents' Association
approximately two to three times per week.
Ceiling-Mounted Unit Ventilators
Due to the difficulty in removing these units, the ceiling-mounted unit
ventilators are being cleaned in place. Access panels are cut into the
ductwork on either side of these units and an access hole is drilled into
the fan housing. The unit ventilator is isolated from the ductwork with
polyethylene isolation barriers. An enclosure is constructed around the
unit, which is kept under negative pressure during cleaning. Fiberglass
insulation is removed from inside the unit. The unit ventilator is cleaned
using HEPA vacuuming, wet and dry wiping, and low volume water cleaning.
Following cleaning, the units are visually inspected and wipe sampled in the
same manner as the floor-mounted units. After the ceiling-mounted units
have passed both the visual inspection and wipe testing, new insulation and
filter are installed in the units and the units are reassembled. The unit
ventilators are kept isolated from the ductwork until the ducts and exterior
louvers have been cleaned by HEPA vacuuming and wiping. In rooms with
ceiling-mounted units, once all unit ventilators in the room have been
cleaned and passed all inspections, a general cleaning is conducted in the
room and two wipe samples for lead are collected from each room. In
addition to inspections being made by the School Construction Authority and
its contractors, the cleaning of the unit ventilators is also inspected by a
consultant to the Stuyvesant High School Parents' Association approximately
two to three times per week.
Central HVAC Systems
Cleaning of the central HVAC systems includes cleaning of all air
conditioning/heating and ventilation air handlers; all connecting supply,
return and exhaust ductwork; and all supply diffusers, grills, dampers and
turning valves. The cleaning is to proceed floor by floor, starting on
the tenth floor. All supply outlets and return grills are to be removed and
cleaned using HEPA vacuuming and wiping. Access doors are to be installed,
if necessary, so that each there is no more than 100 feet between access
points in each duct. The ducts are to be cleaned in sections, with each
section of ductwork sealed or blocked to minimize the spread of
contaminants during cleaning. The ducts are to be cleaned using compressed
air sweep tools, rotating brushes, and/or manual brushing systems. A HEPA vacuum will
be used at the downstream end of each duct segment to collect all dust and
residue. Larger ducts will be entered by cleaning workers and manually
scraped and cleaned with compressed air. Any debris that cannot be removed
via HEPA vacuuming will be manually removed. Ceiling tiles in the vicinity
of supply diffusers and return grills will be HEPA vacuumed and wiped. All
ceiling return plenums and associated ceiling tiles will be HEPA vacuumed.
Air handling units will be vacuumed using a HEPA filtered dry vacuum unit.
Air filters will be removed and replaced with new filters after cleaning is
complete. Coils and fans will be HEPA vacuumed followed by pressure
washing, using isolation barriers as required. Any insulation that cannot
be removed from the HVAC system will be coated with encapsulating paint.
After duct cleaning is completed, each duct will be manually inspected as
well as inspected using video monitoring equipment and will also be photo
documented. In addition to inspections being made by the School
Construction Authority and its contractors, the cleaning of the central
HVAC system units and ducts is also inspected by a consultant to the
Stuyvesant High School Parents' Association approximately two to three times per week.
Once the visual inspections indicate that the systems appear
satisfactorily clean, surface wipe samples will be collected from air
handling units and ductwork. A minimum of six wipe samples per floor will be collected from
the duct system, three from supply ducts and three from return ducts. In
addition, wipe samples will be collected from supply and return dampers in
each air handling unit. The samples in the air handlers will be collected
at similar locations to the samples previously collected by ATC Associates
before cleaning, where possible, but all air handling units will be
sampled, even if they were not previously sampled by ATC.
The School Construction Authority has proposed to use a lead screening level of 20 micrograms per
square foot for the interior duct wipe samples and air handling unit wipe
samples. Once all HVAC system components in each of the major zones has
been cleaned, inspected and satisfactorily tested, a final inspection will
be done of all HVAC components for that zone. The PA's consultant will
participate in those inspections. If the final inspection of an HVAC zone
is satisfactory, that HVAC zone will be turned on and operated with
filters covering all diffusers and vents for a period of up to 24 hours.
The filters will then be removed and aggressive air monitoring will be
conducted with the HVAC system fully operating. The air monitoring will
include the collection of 10 air samples per floor for analysis of asbestos and five
samples per floor for analysis of lead. The results of asbestos testing
will be compared against the asbestos clearance standard of 70 structures
per square millimeter and the lead samples against the USEPA screening
level of 1.5 micrograms per cubic meter.
Carpeting and Upholstery
In the auditorium, all carpeting will be removed and replaced with new
carpeting, and all chair upholstery will be shampooed. In general office
areas, all carpeting will be removed and replaced with new carpeting.
