Trane CVHH CenTraVac Installation, Operation And Maintenance Manual page 42

V V e e n n t t P P i i p p i i n n g g
ASHRAE Standard 15
5 2 2
0.214d (P – P
0 2
L =
2
fC
R
• L = equivalent length of discharge piping, feet
• C = rated capacity as stamped on the relief device
r
in SCFM (conversion: lb/min = SCFM * 0.0764)
C = C C value in lb/min from the preceding table
r
• f = Moody friction factor in fully turbulent flow
• d = inside diameter of pipe or tube, in.
• ln = natural logarithm
• P = absolute pressure at outlet of discharge piping,
2
psi (atmospheric pressure)
• P = allowed back pressure (absolute) at the outlet
0
of pressure relief device, psi
P = (0.15 P) + atmospheric pressure
0
42
) d * ln(P / P )
0 2
–
6f
Table 14. "C" values used to determine rupture disk
vent line sizes (kg/s); for use with the
following figure
Evap. Cond.
Size Size
NTON
(EVSZ) (CDSZ)
900–1200 100M 100M
900–1200 100L 100L
900–1200 130M 130M
900–1200 160M 200M
900–1200 200L 220L
900–1200 220L 220L
1500–1700 200L 200L
1500–1700 220L 220L
900–1200 100M 10HM
900–1200 130M 13HM
900–1200 160M 20HM
1500–1700 200L 20HL
1500–1700 220L 22HL
Notes:
1. Rupture disk diameter is 76.2 mm.
2. Use the total "C" value in the following figure to determine the
vent line pipe diameter.
3. If piping multiple rupture disks (multiple units) to a common
vent line, first determine the total "C" value for each unit, and
then; add all "C" values together and apply the result to the
following figure .
4. The CVHH unit is a Simplex chiller and has (1) refrigerant circuit
and (1) relief device.
"C" Values for Unit Components
Total
Evap. Cond. Econ.
"C"
Tank
Value
0.853 0.368 0.310 0.141 0.034
0.939 0.415 0.349 0.141 0.034
0.932 0.412 0.346 0.141 0.034
1.022 0.461 0.386 0.141 0.034
1.222 0.575 0.473 0.141 0.034
1.284 0.637 0.473 0.141 0.034
1.195 0.575 0.435 0.151 0.034
1.295 0.637 0.473 0.151 0.034
0.967
0.368 0.424 0.141 0.034
1.053 0.412 0.467 0.141 0.034
1.144 0.461 0.509 0.141 0.034
1.332 0.575 0.573 0.151 0.034
1.458 0.637 0.637 0.151 0.034
CVHH-SVX001G-EN
Oil