Trane CVHE Installation, Operation And Maintenance Manual page 43

For CenTraVac™ chillers using a rupture disk relief:
• L = equivalent length of discharge piping, ft (m)
• C = rated capacity as stamped on the relief device
r
in lb/min (kg/s), or SCFM multiplied by 0.0764 lb/
min (convert multiplier in lb/min to kg/s for SI)
C = C C value from the preceding table (convert C C
r
in lb/min to kg/s for SI)
• f = Moody friction factor in fully turbulent flow
CVHE-SVX02M-EN
• d = inside diameter of pipe or tube, in. (mm)
• ln = natural logarithm
• P = absolute pressure at outlet of discharge piping,
2
psi (kPa)
• P = allowed back pressure (absolute) at the outlet
0
of pressure relief device, psi (kPa)
P = (0.50 P) + atmospheric pressure
0
N N o o t t e e : : For rupture disks on CenTraVac ™ chillers, P
is 15 lb (6.8 kg). Atmospheric pressure is at
the elevation of the installation above sea
level; a default value is the atmospheric
pressure at sea level, 14.7 psi (101.34 kPa).
V V e e n n t t P P i i p p i i n n g g
43