A lot of large public projects here
and there, it is missing proper duct cleaning menu
Professional duct cleaning deploys specialized
blowers, vacuums, and brushes to clean out the supply, intake,
and return ducts throughout your home. Duct cleaning should also involve a
thorough cleaning of the air handler, registers, grilles, fans, motors,
housings, and coils of the HVAC system.
A lot of stop and go large public projects
or delayed, disrupted projects, AC units and HVAC ducts has to be cleaned or drops
to be capped for future use
Large public projects usually generate
lots of dust from construction or grinding floors and all that. Reckless AC
subcontractors do not even care to cap the opened ceiling / floor/ wall duct
penetrations during construction with almost no ventilation services
What normally happen is main ducts coming down from air handlers
branching out to rooms and offices dumping air. Normally ductwork is completed a
while before connecting with air distribution and fan coil units. in that
cases, there should be a regulation or code that strictly enforced to cap all
opened duct drops in dusty conditions/ under or no ventilated conditions
especially in large public projects
Top down to here from own past and recent experiences
CDC Duct Cleaning Manual
Recommendations
for the Cleaning and Remediation of Flood-Contaminated HVAC Systems: A Guide
for Building Owners and Managers
Introduction
During flooding, systems for
heating, ventilating, and air conditioning (HVAC) can become submerged in flood
waters. As a result, these systems may contain substantial amounts of dirt and
debris and may also become contaminated with various types of microorganisms
such as bacteria and fungi. The following recommendations will help ensure that
HVAC systems contaminated with flood water are properly cleaned and remediated
to provide healthy indoor environments.
Microorganisms may grow on all
surfaces of HVAC system components that were submerged in flood waters. In
addition, moisture can collect in HVAC system components that were not
submerged (such as air supply ducts above the water line) and can promote the
growth of microorganisms. Therefore, all components of the HVAC system that
were contaminated with flood water or moisture should be thoroughly inspected,
cleaned of dirt and debris, and disinfected by a qualified professional. The
following recommendations will help ensure that HVAC systems contaminated with
flood water are properly cleaned and remediated to provide healthy indoor
environments.
These recommendations will be
reassessed periodically and updated as appropriate.
Steps Before Cleaning and
Remediation
· If the building is to remain partly occupied (for example, on
upper floors not affected by flood waters), isolate the construction areas
where HVAC systems will be cleaned and remediated by using temporary walls,
plastic sheeting, or other vapor-retarding barriers. Maintain the construction
areas under negative pressure (relative to adjacent non-construction areas) by
using blowers equipped with HEPA filters (high-efficiency particulate air
filters) to exhaust the area. To ensure complete isolation from the
construction areas, it may be necessary to pressurize the adjacent non-construction
areas and temporarily relocate the outdoor-air intake for the HVAC system
serving the occupied areas.
· Take precautions to protect the health of workers who are cleaning
and remediating the HVAC system. Make sure that workers wear at least an N-95
NIOSH-approved respirator to protect against airborne microorganisms. Increased
levels of respiratory protection (for example, powered, air-purifying
respirators equipped with high efficiency filters) may be appropriate depending
on the level of visible contamination. In addition, when using chlorine bleach
or other disinfectants in poorly ventilated environments, it may be necessary
to use appropriate chemical cartridges in addition to the particulate filters
to protect workers from breathing the chemical vapors. Employers must implement
a complete respiratory protection program that meets the requirements of the
OSHA respiratory protection standard (29 Code of Federal Regulations 1910.134).
The minimum requirements for a respiratory protection program include a written
standard operating procedure for the following: selecting and using
respirators; the medical evaluation of workers to determine whether they are
physically able to wear the respirator selected for use; training and
instructions on respirator use; the cleaning, repair, and storage of
respirators; the continued surveillance of work area conditions for worker
exposure and stress; and a respirator fit-testing program. For tight-fitting
respirators, fit-testing is necessary to help ensure that the respirator fits
tightly, reducing the potential for leakage of outside air from around the edge
of the mask. In addition, employers must provide workers with appropriate skin,
eye, and hearing protection for the safe performance of their jobs.
HVAC Cleaning and
Remediation
· Remove all flood-contaminated insulation surrounding and within
HVAC system components. Discard these contaminated materials appropriately
following applicable Federal, State, and local regulations.
· Remove contaminated HVAC filter media and discard appropriately
following applicable Federal, State, and local regulations.
· After removing any insulation and filters, clean all
flood-contaminated HVAC system component surfaces with a HEPA-filtered vacuum
cleaner to remove dirt, debris, and microorganisms. Pay special attention to
filter racks, drain pans, bends and horizontal sections of air ducts where
debris can collect.
· After removing any insulation or debris, disinfect all HVAC system
component surfaces while the HVAC system is not operating. Use a solution of 1
cup of household chlorine bleach in a gallon of water. Do not mix bleach with
other cleaning products that contain ammonia.
· Conduct the cleaning and disinfection activities in a
clean-to-dirty work progression. Consider the use of auxiliary fans to supply
“clean” air to the worker position and carry aerosolized contaminant and
disinfectant in the clean-to-dirty direction, away from the worker’s breathing
zones and towards the point of filtration and exhaust.
· Follow the disinfection procedure with a clean water rinse.
Depending on the amount of debris present, it may be necessary to mechanically
clean the HVAC system component surfaces with a steam or a high-pressure washer
before using the disinfectant. Gasoline powered pressure washers should be used
outside away from air intakes to prevent carbon monoxide hazards. (See NIOSH
topic webpage, “Carbon Monoxide Hazards from Small Gasoline Powered Engines”)
Note: Remove and discard HVAC
system components that are contaminated with flood water, and cannot be
effectively cleaned and disinfected. Replace them with new components.
· After cleaning and disinfecting or replacing the HVAC system
components, replace the insulation – preferably with an external (i.e. not in
the air stream) smooth-surfaced insulation to help prevent debris and
microorganisms from collecting in the future.
· Make sure that the HVAC system fan has been removed and serviced
(cleaned, disinfected, dried thoroughly, and tested) by a qualified
professional before it is placed back into the air-handling unit.
· During the cleaning and remediation process, consider upgrading
the HVAC system filtration to the highest efficiency filters practical given
the static pressure constraints of the HVAC system fan. This step has been
shown to be one of the most cost-effective ways to improve the long-term
quality of the indoor environment, since it reduces the amount of airborne
dusts and microorganisms.
Resuming HVAC Operations
· After cleaning and disinfecting or replacing HVAC system, have a
qualified professional thoroughly evaluate its performance and correct it as
necessary before the building is occupied again. The HVAC system performance
should conform to the recommendations contained in ASHRAE Standard 62.1-2016,
Ventilation for Acceptable Indoor Air Quality.
· Before the building is occupied again, operate the HVAC system
continuously in a normal manner at a comfortable temperature for 48 to 72
hours. During this period, it may be beneficial to open the HVAC outdoor air
dampers to the maximum setting that still allows you to provide the desired
indoor air temperatures. If objectionable flood-related odors persist after
this “flush out” period, reassess by looking for flood-contaminated areas that
were not identified earlier and continue the flush-out process until odors are
no longer apparent. Replace the HVAC filters used during the flush-out prior to
building occupancy.
· After a building is occupied again, make frequent (for example,
weekly) checks of the HVAC system to ensure that it is operating properly.
During these checks, inspect the HVAC system filters and replace them when
necessary. Gradually reduce the frequency of the HVAC system checks to monthly
or quarterly inspections, depending on the routine operation and maintenance
specifications for the HVAC system.
· If no routine operation and maintenance program is in place for
the HVAC system, develop and institute such a program. At a minimum, include
the following routine procedures: inspection and maintenance of HVAC
components, calibration of HVAC system controls, and testing and balancing of
the HVAC system.
· After the building is occupied again, maintain the interior
temperature and relative humidity to conform with the ranges recommended in
ASHRAE Standard 55- 2013, Thermal Environmental Conditions for Human Occupancy
Indoor
air pollution is a hot topic these days and like every new industry, everyone
is trying to get their piece of the pie. Air duct cleaning is just one
part of a broader industry aimed at increasing indoor air quality and promoting
good health. Duct cleaning is a service provided by some companies who
utilize vacuums, brushes and chemical cleaning compounds to scrub the inside of
your air conditioning ducts and HVAC coils, including supply and return air
ducts, heat exchangers and evaporator coils. The claim is that this will
increase the health of you and your family by decreasing the number of
contaminants in your air
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