Trane Tracer UC400 Installation, Operation And Maintenance Manual page 64

S S e e t t t t i i n n g g s s f f o o r r C C O O - - B B a a s s e e d d D D e e m m a a n n d d C C o o n n t t r r o o l l l l e e d d V V e e n n t t i i l l a a t t i i o o n n
2 2
•
64
CO = concentration of CO
2outdoors
N = rate at which CO is generated by the zone occupants, cfm/person
2
The rate at which the occupants produce carbon dioxide (N) varies with diet and health, as
well as with the duration and intensity of physical activity. The following table suggests
typical values for various activity levels:
Occupant Activity Level
(a)
Sleeping
Seated, Quiet
Seated, Typing
Seated, Filing
Walking (2 mph)
Lifting/Packing
Light Machine Work
Heavy Machine Work
(a) A more complete table of Met levels for various activities can be found in Chapter 9 (Table 4) of the 2013 ASHRAE
Handbook-Fundamentals. According to the Standard 62.1 User's Manual (Appendix A), the CO
averages about 0.0084 cfm/met/person over the general adult population.
Unless the outdoor air intake is located very close to an area with heavy traffic, it is fairly
common for design engineers to assume the outdoor concentration (CO
ppm.
E E x x a a m m p p l l e e : : For this example K-12 classroom, the CO
assumed to be 0.0101 cfm/person, and the outdoor CO
assumed to be 400 ppm. As calculated in Step 1, when this zone is fully occupied (P
design outdoor airflow rate (V
CO = CO
2space-Design 2outdoors
CO = 400 ppm + [1,000,000 x 0.0101 cfm/p / (470 cfm / 35 people)] = 1200 ppm
2space-Design
The steady-state indoor CO
(P = 0) will be equal to the outdoor CO
z
E E x x a a m m p p l l e e : : For this example K-12 classroom, the outdoor CO
400 ppm.
CO = CO
2space-DCVmin 2outdoors
If the information is not known to complete the calculations in Steps 1 through 4 above, then
as long as the Occupancy Category and zone floor area (ft
calculated using the default occupant density from ASHRAE Standard 62.1 and an assumed
CO generation rate (N). Refer to the following table for common occupancy categories.
2
in the outdoor air, ppm
2
CO2 Generation Rate (N), cfm/
Met Person
0.7 0.0059
1 0.0084
1.1 0.0092
1.2 0.0101
2 0.0168
2.1 0.0176
2.2 0.0185
4 0.0336
) is 470 cfm.
bz-Design
+ [1,000,000 x N / (V
bz-Design
concentration (CO
2
2space-DCVmin
concentration.
2
= 400 ppm
generation rate (N)
2
2outdoors
generation rate (N) of the occupants is
2
concentration (CO
2
2outdoors
/ P )]
z-Design
) when the zone has no occupants
concentration is assumed to be
2
2 ) are known, these values can be
) to be 400
) is
= 35), its
z
BAS-SVX48H-EN