SpectraPure
®
SpectraPure
®
Inc.
480.894.5437 Call us toll-free 1.800.685.2783
2167 East Fifth St, Tempe, Arizona 85281
15
REVERSE OSMOSIS MEMBRANE PRODUCTION CALCULATION
Actual production of a membrane is dependent on two factors: Tap Water Pressure and Tap Water Temperature. In order
to characterize a membrane, there must be common testing data. Industry standards for testing membrane performance
are:
60 PSI tap water pressure and 77
°
F (25
°
C) tap water temperature. Most locations will not have exactly 77 degree water.
Use the calculation below to determine what the membrane should produce with your water conditions.
PRESSURE COMPENSATION:
The output (GPD) is directly proportional to the applied pressure. The Performance Plus System uses an RO Membrane
which is nominally-rated to produce 90 GPD at 60 psi. To compute the Pressure Compensation Factor (PCF), divide the
applied pressure (read from the Pressure Gauge on the membrane housing) by 60. Since the system has an integrated
booster pump, the PCF should be greater than 1.
TEMPERATURE COMPENSATION:
The output (GPD) decreases with a decrease in temperature. This is due to water viscosity increasing with a decrease in
water temperature. Look up the water temperature on the chart below to determine the Temperature Compensation Factor
(TCF) value.
MEMBRANE OUTPUT CALCULATION EXAMPLE:
What is the expected GPD from a 90 GPD membrane at 80 psi water pressure and 59
°
F water temperature?
PCF = 80 ÷ 60 = 1.3
TCF = 0.73
Expected GPD = 90 x 1.3 x 0.73 = 85.4 GPD ±20%*
*Membrane manufacturers’ state their flow ratings as having a factor of ±20%.
Temperature Correction Factor Table (TCF)
°F /°C
TCF
°F /°C
TCF
°F /°C
TCF
41.0 /5
0.521
59.0 /15
0.730
77.0 /25
1.000
42.8 /6
0.540
60.8 /16
0.754
78.8 /26
1.031
44.6 /7
0.560
62.6 /17
0.779
80.6 /27
1.063
46.4 /8
0.578
64.4 /18
0.804
82.4 /28
1.094
48.2 /9
0.598
66.2 /19
0.830
84.2 /29
1.127
50.0 /10
0.620
68.0 /20
0.857
86.0 /30
1.161
51.8 /11
0.640
69.8 /21
0.884
87.8 /31
1.196
53.6 /12
0.661
71.6 /22
0.912
89.6 /32
1.232
55.4 /13
0.684
73.4 /23
0.941
91.4 /33
1.267
57.2/14
0.707
75.2 /24
0.970
93.2 /34
1.304
MAINTENANCE PROCEDURES (continued)
(Maintenance Procedures are continued on next page)
