DiamaPro Systems DPBRN27-X+ - Page 16

16.4. Understanding Factors that Determine Carbon
Monoxide Levels
The primary factors that ultimately determine the expected level of Car-
bon Monoxide in a space where a propane machine is operating are as
follows:
• Room air volume
• Air Exchange Rate (ventilation rate)
• Carbon Monoxide Production Rate
Room air volume can be determined by multiplying the length, width, and
height of a room, and then reducing for any material in the room.
For example: A room that is 100 ft x 100 ft with a 10 ft ceiling has a volume
of: 100 x 100 x 10 = 100,000 cubic feet, when empty. If the room consists
of 80% open air, and 20% material, the total room air volume = 100,000 *
80% = 80,000 cubic feet.
Air Exchange Rate is a measure of the room’s ventilation. Air exchange
rate is typically measured in terms of the qty of air changes per hour
(ACPH). In other words, the Air Exchange Rate when expressed as
ACPH, measures the frequency (per hour) that the room’s air is replaced
by fresh air. The higher the ACPH, the more frequently air is being ventilat-
ed, for example:
In a room with ACPH = 6, the room’s air would be completely extracted
and replaced by fresh air 6 times every hour, or once every 10 minutes.
Here are some air exchange rates, expressed in ACPH, that would be
expected in di󰀨erent types of industrial and commercial spaces:
Carbon Monoxide Production Rate is, itself, the result of several factors:
• The total ow of engine exhaust, which is determined by the relative
amount of engine load of application
• The amount of Carbon Monoxide present in the exhaust, expressed as PPM
• The quantity of propane engines in operation
A 603cc propane engine under normal operating conditions (50% of max-
imum load) will produce total exhaust at a rate of 13 CFM (cubic feet per
minute), with Carbon Monoxide making up 50 PPM of the total exhaust.
Therefore, the CO production rate (in CFM) is calculated as follows:
Qty of Engines * Exhaust Flow per Engine (CFM) * CO Level of Exhaust
(PPM)
Calculating the CO production rate of one 603cc engine operating under
normal conditions is as follows:
1 engine * 13 cubic ft / min per engine * 50 / 1,000,000 = 0.00065 cubic
feet/min
Knowing all of these factors, we can calculate the equilibrium carbon
monoxide level of a room (in PPM) as follows:
Total CO production rate (in cubic feet / min) * Air Exchange Rate
(expressed in minutes) *1,000,000 Room air volume (in cubic feet)
Basement Parking
Residential Basement
Bedroom
Residential Bathroom
Residential Living Rooms
Residential Kitchen
Residential Laundry
Business O󰀩ces
Business Lunch Break Rooms
Business Conference Rooms
Business Copy Rooms
Computer Rooms
Restaurant Dining Area
Restaurant Food Staging Area
Restaurant Bar
Public Hallway
Public Retail Store
Public Foyer
Church
Public Auditorium
Commercial kitchens & Restrooms
Smoking rooms
Laboratories
Classrooms
Warehousing
15–30
3–4
5-6
6-7
6-8
7-8
8-9
6-8
7-8
8-12
10-12
10-14
8-10
10-12
15-20
6-8
6-10
8-10
8-12
12-14
15–30
15-20
6–12
3–4
3-10
This table shows the calculated equilibrium carbon monoxide level under
di󰀨erent examples with varying inputs:
There are several important notes to take away from these calculations:
• More engines running in a space leads to higher room CO level. This is
shown comparing Examples No. 1 & 2.
• Smaller room size leads to higher room CO level. This is shown compar-
ing Examples No. 2 & 3.
• Lower ventilation (Air Exchange Rate) leads to higher room CO level.
This is shown comparing Examples No. 3 & 4.
• Higher CO level in the exhaust leads to higher room CO level. This is
shown comparing Examples No. 4 & 5.
DANGER: Operating this machine or any propane powered
engine in a space with NO ventilation (a sealed space), is guar-
anteed to result in dangerously high level of CO, that will cause
serious injury or death to the operator and bystanders. Never
operate the machine in a sealed space with no ventilation.
Reviewing the above section, we already know that to reduce CO expo-
sure the following action should be taken:
• Limit the quantity of engines running in a space.
• Insure adequate ventilation. Higher ventilation rates (higher air exchange
rate) will always result in lower CO exposure.
• Insure proper maintenance and performance of engine to avoid high CO
content in engine exhaust.
• All of these tips are especially important to follow when using the ma-
chine in small spaces.
This section o󰀨ers additional considerations and best practices to reducing
Carbon Monoxide exposure:
• Air Exchange and CO Di󰀨usion
• Application Considerations
• Examples of CO Management in Spaces
• Maintenance of Equipment
The most reliable method to prevent CO Poisoning is to ensure all the CO
produced is vented outside. With wood stoves or gas heaters this is per-
formed with ductwork that carries the exhaust and CO outside. Non-sta-
tionary combustion type equipment must be used in such a way that CO
is not allowed to rise to a harmful or dangerous level. CO does not readily
dissipate or mix with air on its own. Air currents can “stir” the CO and dilute
the concentration or ppm values by mixing it with the available air. When
using equipment over a large area in a short time “stirring” occurs as you
walk, or to say it another way, your E󰀨ective Operating Zone is large.
When activity is concentrated to a smaller area as in a stripping applica-
tion, the E󰀨ective Operating Zone is small, and “stirring” must be forced by
the use of fans to increase the E󰀨ective Operating Zone and reduce high
concentrations of CO. “Air” exchange rates (air exchange is dened as
the exhausting of internal air to the external atmosphere), the size of the
E󰀨ective Operating Zone, amount of CO produced, level of human activity,
and the duration of exposure are all factors in the determination of the
production of carboxyhemoglobin and the amount of CO blood saturation.
16.5. Methods to Reduce Carbon Monoxide Exposure
16.6. Air Exchange and CO Di󰀨usion