Download Report 2 - CSA Group

flow volume and concentration were stored in EPA (25C) standard conditions. Metered flow
type is no longer used on production BAM-1020 units.
5.3 About Leak Checks, Nozzle Cleaning, and Flow Checks
The three critical aspects of BAM-1020 flow system maintenance are routine leak checks,
nozzle and vane cleaning, and flow checks or calibrations. Agencies who routinely verify
these three aspects almost always obtain high-quality concentration data from the unit. The
minimum service interval is two months, which is the interval for replacing the filter tape.
However, many agencies opt to perform leak checks, nozzle/vane cleaning, and flow audits
on a monthly basis, and this service interval is recommended by Met One whenever possible.
Complete flow system maintenance typically requires less than 10 minutes to perform.
The best order for the monthly flow system checks is:
1.
2.
3.
4.
As-found leak check.
Nozzle and vane cleaning.
As-left leak check. (If a leak was corrected)
Three-point flow check/audit and calibration if required.
If an air leak is found in a BAM-1020 system, it is almost certain to occur at the interface
between the nozzle and the filter tape due to debris buildup. There is normally an insignificant
amount of leakage at the tape interface, but an excessive leak lets an unknown portion of the
16.7 L/min sample flow to enter the system at the leak point instead of the inlet. This could
cause the total volume of air sampled through the inlet to be incorrect, and the resulting
concentration data could be unpredictably biased. The BAM-1020 has no way of
automatically detecting a leak at the tape/nozzle interface because the airflow sensor
is located downstream of the filter tape. Allowing a significant leak to persist may
result in concentration data being invalidated! Routine leak checks and nozzle cleaning
prevent any significant leaks from forming. Performing an as-found leak check before
cleaning the nozzle or performing any service is a key method for validating previous data.
Even if the leak check value is found to be within acceptable bounds, the nozzle and vane
should still be cleaned anyway to ensure continued leak-free operation.
5.4 Leak Check Procedure
Perform the following steps to check for leaks in the BAM-1020 system:
1. Enter the TEST > TAPE menu on the BAM. This will stop the operation cycle of the
unit. Press the FWD soft key to advance the tape 1 “window” to a clean, unused spot.
2. (Optional) Some users perform an as-found flow check/audit before performing any
further service. If so, install your flow reference on the inlet, and check the 16.7 flow
point in the TEST > FLOW screen. Record the as-found flow rate, but do not calibrate
any of the flow parameters until the leak checks and nozzle cleaning are finished.
3. Remove the PM10 head from the inlet tube and install a BX-305 or equivalent leak test
valve onto the inlet tube. If a PM2.5 cyclone is used, install the leak check valve on top
of the cyclone, since the cyclone is a possible source of leaks and should be tested.
Turn the valve to the OFF position to prevent any air from entering the inlet tube.
4. Enter the TEST > PUMP menu and turn the pump on. The standard flow rate shown
on the BAM display should stabilize at less than 1.0 L/min in about 20 seconds.
Page 36
BAM-1020-9800 REV K