EMSA 22 CCSF
Lab Module 3B . Calibration of High and Low Flow Air sampling Pump Using a Secondary Calibration
Standard (Field Rotometer)
Introduction:
An essential part of any sampling is an accurate measurement of the quantity of air that was sampled.
The flow rates of the pumps and the flow measuring devices must be calibrated prior to any sampling
event. For evaluating a work place exposure to an air contaminant the volume of air collected depends
on proper the flow rate (liter/min). After collecting a sample, one calculates the concentration of a
contaminant in air as the amount of contaminant collected divided by the volume of air drawn through
the sample media (e.g., filter, adsorption tube, etc.).
Flow Rate (L/min) X Time (min)=Air Volume (L)
Mass of contaminant (mg) /Air Volume (liter or m3)=Concentration of contaminant in air (mg/L or
mg/m3)
In this experiment you will:
 Become familiar with secondary calibration device “ a Rotometer “ commonly used in the field
 Learn to calibrate a high flow and low flow pump sampling pump using a sample media and the
rotometer.
Materials/Equipments
Pumps (SKC):
1)High flow portable sampling pump with flow rate of 1-32 L/min
2) Low flow Portable sampling pump with flow rate of <1 liter/min
Rotometer (SKC)
The most common air flow calibration device used in the field (and often in the laboratory) is the
rotameter. The rotameter consists of a tapered vertical tube containing a float (ball). The float rises to a
height which is dependent on the flow rate and density of air moving through the tube.
Filter media
1) 37 mm Filter cassettes (usually used with high flow pump for variety of air sampling exp. Asbestos or
Lead)
2) Charcoal tubes (for measuring volatile organic contaminant using low flow pump)
Other materials needed:
-Tygon tubing
-Small slotted screw driver
-Small Phillips screw driver
- Adjustable flow holder manifold for low flow pump
Procedures-Calibration of High Flow Pump:
1) Instructor will demonstrate the calibration set up. At minimum first become familiar with pumps (how
to turn the pumps on/off.
2) Record in the field log, the serial numbers of the rotameter and the sampling pump, and label
these to identify them for your team (2-3 people).
EMSA 22 Lab Module Calibration of Air sampling Pump
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EMSA 22 CCSF
3. Assemble the apparatus as shown in Fig.1 below
4. Adjust the pump air flow setting through its full range to determine roughly the corresponding range
of rotameter settings. For example, the range might be from
about 1 to about 30 L/min for high flow.
5. Without any filter cassette in line, adjust the pump to draw 1 L/min on the rotameter. Record the
rotometer readings in the field log form provided.
6. Without changing the pump setting, place a 37 mm Filter cassette in
Line as shown below in Picture. Note the (upstream) rotameter reading and record in your Field log form
Figure 1. Connect the inlet of the sampling pump to the outlet of the
sampling medium (shown in Black). Connect the inlet of the sampling medium to the outlet of the
rotameter.
8. Adjust the pump pressure (black) to 5 L/min as measured on the rotometer. Record the flow in the log
sheet.
9. Turn pump off- the pump is now ready for sampling at 2.8L/min flow rate using 37 mm cassette.
Question: Does placing a filter in line change the flow measured on the
pump? Is there an increase or drop in pressure across the filter due to resistance?
Procedures- Calibration of low flow personal sampling pump
1) Charge SKC personal sampler pump for a minimum of 14 hours by connecting charger plug to sampler
charging jack unless using AC power to run pump. Record pumps’ serial number.
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EMSA 22 CCSF
2) Test the SKC personal sampler pump for full charge by turning the sampler on using “On” switch. The
float in the flow window should start moving upward.
3) After completing the battery test, remove the protective cap covering the regulator shutoff cap
screw.
4) Open the regulator shutoff valve by turning the adjustment screw ~3 turns counter-clockwise with a
small screwdriver. Replace the protective cap.
5) Connect an adjustable flow holder to the tubing attached to the filter housing intake.
6) Break the ends of the charcoal tube and Connect to the rubber or tubing connector of the adjustable
flow holder.
Be sure the tubing is connected to the correct end of the sample tube (air flow direction is
indicated on side of charcoal tube).
7) Connect a Rotameter to the exposed end of the sample tube. Loosen the anti-tamper cover on the
manifold of the adjustable flow holder to expose the manifold’s flow adjustment screw(s).
8) Turn on the sampler and turn the manifold’s slow adjustment screw(s) until the desired flow rate of
( 0.2 liter /min ) is obtained record in the log sheet.
9) Cover the manifold’s flow adjustment screw(s) with the anti-tamper cover and tighten. Turn off the
sampler.
10) The low flow pump is now calibrated to flow rate of ( 0.2 L /min ) using a charcoal tube.
11)Test rotameter against a calibrated sample pump before each study.
Same Question: Does placing a charcoal tube in line change the flow measured on the
pump? Is there an increase or drop in pressure across the tube due to resistance?
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