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FAQs

1. Is the MIP a continuous sampling tool?

Yes. The MIP samples the gas stream continuously not just when stopped at an interval.

2. Can the MIP be used for plume delineation?

Yes. The MIP is intended to be used for delineation of plumes. The MIP is designed as a screening tool to locate the source area and delineate the plume out to 1ppm (depending of the detector used).

3. Can the MIP be used in the source area?

Yes. There are some limitations to length of time that the MIP can stay in the source area. If a source area is encountered the operator should try to push through the area to the next relatively clean zone. If the operator decides to stay in the source then the trunkline will become contaminated and have a high baseline until cleaned.

4. What is the Detection Limit of the MIP?

1ppm BTEX compounds with a PID
5ppm Chlorinated solvents with a PID
200ppb Chlorinated solvents with an ECD

5. What are the limiting factors for the Detection Limit?

Detectors being used
Membrane wear
Trunk line carryover
Rate of penetration into the subsurface

6. Does MIP work in the saturated and unsaturated soils?

Yes.

7. Is there a difference in detection limits in saturated vs. unsaturated soils?

Saturated soils tend to yield a slightly lower detection limit.

8. How do you choose and measure the experience of MIP clients?

This can be done by the number of detectors being used, their knowledge of each detector, and the type of graphical output the client is capable of providing.

9. What is the order of .dat and .gas files and labels?

MIP(.dat file): depth, conductivity, speed, temp (min), temp (max), pressure, depth (meters), speed (m/min), pressure(kPa)
MIP(.gas file): detector1(min), detector1(max), detector2(min), detector2(max), detector3(min), detector3(max), detector4(min), detector4(max).

10. What are the units displayed for EC and MIP detectors?

EC is displayed in milli siemens per meter (mS/m)
MIP detectors are in micro Volts (uV)

11. How does the contaminate move across membrane?

Contaminates move through the membrane via diffusion. The membrane is heated to encourage the contaminate to volatilize to more easily diffuse through the membrane.

12. What is the testing procedure for the MIP system?

Geoprobe® Systems recommends Aqueous phase testing of the MIP. The aqueous phase test provides a known response in uV to a known concentration of contaminate. The contaminate used for this testing should reflect the contaminate being analyzed for on each unique site.

13. What detectors can be used with the MIP system?

Any lab grade gas phase detector can be used.

Examples:

PID
FID
ECD
XSD
DELCD

14. Is the probing rate critical?

Probe rate should always stay consistent throughout a site. We recommend 1ft/min. Keeping the probe rate consistent will help correlate all MIP logs at that site.

15. How do I determine if this is affordable compared to traditional sampling methods?

Determine the number of samples that would be taken through traditional techniques and then decide if this number could be reduced by knowing exactly where the contamination is instead of continually sampling. As of now the price for lab work varies from $150.00 to $170.00 for a GC analysis of VOC's and $175.00 to $205.00 for GC/MS VOC analysis.

16. Why should I run a response test instead of a sanity test?

A response test deals with a known concentration of contaminate. Whereas a sanity test just puts pure product or gasoline on a cloth rag directly in contact with the membrane. Putting pure product onto the membrane can hide membrane problems and also contaminate the trunk line.