Scope
This Guideline provides a method to verify the flow rate present in the
sampler / density fast loop is isokinetic. This is achieved by calculating
the velocity of product in the fast loop and comparing it to the velocity in
the main line. The fast loop velocity must be between 40 and 200% of
the main line velocity.
Frequency: 3 Months
Procedure PREPARATIONS:
Give a brief description of the test in the Metering Log Book.
Ensure that this check is undertaken with product flowing in the fast
loop. Record the results of the test on Fast Loop Flow Rate Test
Sheet, attached.
PROCEDURE:
The fast loop flow shall be checked using the following procedure:
–
a) Observe the flow rate in the fast loop at the flow rate
indicator. This may be a variable area flow meter or a paddle
device.
b) Simultaneously observe the flow rate in the main line from
which the fast loop is fed. It may be necessary to sum the
meters in service.
f) Calculate the velocities in the fast loop and the main line as
shown on the Test Sheet, attached.
g)
If the velocity in the fast loop is between 40 and 200% of the
velocity in the main line the test is complete.
h)
If the velocity in the fast loop is not between 40 and 200% of
the velocity in the main line attempt corrective action and
repeat the test. Corrective action may involve opening or
closing a restriction (isolation or control valve).
i) Once the velocity in the fast loop is within tolerance the test
is complete. Enter details on the test sheet.
f) Enter details of all tests in the Metering Log Book.
FAST LOOP FLOW RATE TEST SHEET
