Honeywell E3Point Application Note
Parking Garage Guide
This step-by-step guide describes set-up
procedures to help provide a safe parking
garage while minimizing energy costs
associated with ventilation and heating.
CO and NO2 Monitoring
Systems for Parking
Structures
Codes and Standards
Step 1: Determine the reason(s) why
you want to detect the presence of carbon
monoxide.
• Safety: In any facility where people are working
or the public and tenants may be active, there
must be due diligence on the part of the owner to
assure a safe breathing environment.
• Economics: To provide fresh air in a facility where
vehicles are present, a pre-determined air change
per hour is required. This can be expensive for a
number of reasons:
1) The electrical energy required to run the fans
can be high.
2) The fans run continuously which incurs wear
and shortens motor life.
3) The frequency of required maintenance is
higher for belt and lubrication services.
4) The heat loss in a garage is higher with the
high volume of air changes.
• Aesthetics: In private facilities, the outside fan
noise and loss of heat within the garage can
affect tenant satisfaction.
In parking structures, CO and NO2 are
two of the most abundant airborne
contaminants and poses significant
safety concerns. The CO and NO
levels
2
must be controlled or ventilated when
concentrations approach unsafe levels.
Various gas monitors are available for use in parking structure
applications. The specifics of the design determine what type of monitor
or monitoring system best suits the application. This detailed, easy-touse guideline assists the design engineer in the selection of an optimal
gas detection solution.
The 301C is able to monitor up to 96 hardwired
transmitters and has a series of relays which
can activate alarms and/or ventilation equipment
as required.
Step 2 : What the ASHRAE handbook says
about carbon monoxide detection in parking
garages:
• “The operation of automobiles presents two
concerns. The most serious is the emission of
carbon monoxide, with its own risks.”
• “The second concern is the presence of oil and
gasoline fumes…the ventilation required to dilute
carbon monoxide to acceptable levels will also
control the other contaminants satisfactorily.”
• “To conserve energy, fan systems should be
controlled by carbon monoxide meters with
multiple fan or variable speed stages for larger
systems, if permitted by local codes. In multilevel parking garages or single-level structures of
extensive area, independent fan systems, each
under individual control, are recommended.”
• “The ventilation system in parking garages, in
general, moves large quantities of air through
large openings without extensive ductwork. These
conditions, in addition to the highly reverberant
nature of the space, contribute to high noise
levels.”
Step 3 : Building codes and carbon monoxide
monitoring
• International Mechanical Code - Section 403.5
Public garages - Mechanical ventilation systems
for public garages are not required to operate
continuously where the system is arranged
to operate automatically upon detection of a
concentration of carbon monoxide of 25 ppm by
approved detection devices.
• Uniform Building Code - Section 705 - In all
parking garages…automatic CO sensing devices
may be employed to modulate the ventilation
system to maintain a maximum average of CO
of 50 ppm during any eight-hour period, with a
maximum average concentration not greater 200
ppm for a period not exceeding one hour…
• State, municipal and other building codes
- Most state, and local municipal building
codes recognize and recommend using carbon
monoxide monitors in enclosed parking garages.
If the building code in your area does not have
any provisions for CO monitoring, do not forget
that carbon monoxide is still a very dangerous
gas to personal health and safety. Therefore, the
use of common sense by design engineers is still
the best “building code” to use.
Codes, Standards and
Sequence of Operation
Step 4: Carbon monoxide and nitrogen dioxide toxicity levels and related health symptoms
Table 1 – Carbon Monoxide Toxicity Levels and Related Health Symptoms
CO Level in Air
In parts per million In %
12,800 ppm 1.28% Death within 1 to 3 minutes
6,400 ppm 0.64% Headache, dizziness in 1-2 minutes. Death in 10-15 minutes
3,200 ppm 0.32% Headache, dizziness, nausea within 10 minutes. Death within 30 min.
1,600 ppm 0.16% Headache, dizziness, nausea within 20 minutes. Death within 2 hours
800 ppm 0.08% Headache, dizziness, nausea within 45 minutes, convulsions. Coma within 2 hours
400 ppm 0.04% Frontal headache 1-2 hours, widespread 2 ½ to 3 ½ hours
200 ppm 0.02% Slight headache, tiredness, dizziness, nausea after 2-3 hours
Nitrogen Dioxide Toxicity Levels and Related Health Symptoms
NO2 Level in Air Toxic Symptoms and Target Organs
5 ppm Chronic bronchitis, emphysema
5 ppm Eye, nose, and upper respiratory irritation
5 ppm Chronic bronchitis, emphysema
5 ppm Eye, nose, and upper respiratory irritation
5 ppm Chronic bronchitis, emphysema
5 ppm Eye, nose, and upper respiratory irritation
1 ppm Mild headache
1 ppm Acute pulmonary edema; lower respiratory irritation (cough, dyspnea)
1 ppm Eye, nose, and upper respiratory irritation
0.2 ppm Lower respiratory irritation
Toxic Symptoms and Time Breathed
• Monitoring system malfunction:
1) Activate a buzzer inside the gas detection
system controller.
2) May notify the building automation system (if
available) through a fault relay of the controller.
3) Secondary activation might be required:
warning strobe light (blue).
Step 6: Mechanical ventilation
considerations
• Two main factors are required to size the
ventilation system:
1) The number of cars in operation
2) The carbon monoxide emission quantities
• Most codes simplify this estimate by requiring
four (4) to six (6) air changes per hour for fully
enclosed garages. Consult local codes for the
specific requirements.
• The carbon monoxide monitoring system must
be capable of activating both the exhaust fan(s)
and the air intake device(s) such as outside air
louvers/dampers and make up air units
• IMPORTANT: As per the Uniform Mechanical
Code: Connecting offices (to parking garage),
waiting rooms, ticket booths, etc., shall be
supplied with conditioned air under positive
pressure.
• Carbon monoxide poisoning is a form of
asphyxiation. Carbon monoxide combines with
hemoglobin, the oxygen-carrying constituent of
blood, 210 times more readily than does oxygen.
Carboxyhemoglobin is then formed. Carbon
monoxide lowers the oxygen carrying capacity
of blood and interferes with necessary gaseous
exchange functions.
• Human health effects can vary significantly based
on overall state of health, sex, age and weight.
• Many studies have shown that the CO content
in exhaust gases of individual vehicles varies
greatly. This variation is caused by such factors
as the age of the vehicle, carburetor adjustment
or injector condition, quality of fuel, engine
horsepower, level of maintenance, and differing
driving habits of motorists.
• Levels of carbon monoxide in garages vary
depending on:
1) Number of cars running
2) Length of travel and operation time of cars in
the garage
3) Emission rate of vehicle
4) Acceptable contaminant level within a given
facility
Sequence of Operation
Step 5: Carbon monoxide alarm levels and
recommended sequence of operation
• First alarm level:
1) Set at low concentration. See Table 2 for
recommended low alarm level).
2) Gas monitoring system shall be able to actuate
exhaust fans and outside air intake devices to
bring the carbon monoxide level down to an
acceptable level.
3) Optional: if the parking structure is equipped
with either two-speed fans or with a second set
of fans, only the first speed of fans or the first set
of fans should be actuated.
• Second alarm level:
1) Set at high concentration. See Table 2 for
recommended high alarm level).
2) Ventilation equipment previously actuated
at low level in the parking garage shall remain
operational.
3) Optional: if the parking structure is equipped
with either two-speed fans or with a second set
of fans, they should be activated at full speed or
all fans should be activated.
4) Activation of strobe light (red) and horn might
be required.
5) People might be required to evacuate the
parking garage.
3
Point utilizes cutting edge technology in order
The E
to accurately and reliably monitor carbon monoxide
and Nitrogen Dioxide (diesel fumes) levels.
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