sampling

December 2017

Triangle NoTES

 

December 2017

 

I hope everyone has a very Happy Holiday period with friends and family!

 

I have had a couple of discussions of late concerning hazardous sampling locations and there seems to be quite a bit of confusion over what that would include and what documentation there has been concerning the requirements.

 

The major documentation I have seen is that which is included in the method under section 6.1.1 which states:

 

NOTE: If it is not possible to use a heating system for safety reasons, an unheated system with an in-stack filter is a suitable alternative.

 

In my opinion, and in concurrence with various regulatory entities regarding discussions on the matter, this only applies to situations where flammable gases would require the use of intrinsically safe equipment to limit the possibility of fire or explosion. In my experience to date, there have been few sources outside of the petrochemical, natural gas, or landfill operations which have possibly met this requirement. The recent discussions about the use have all been in facilities where there was no flammability issue documented as the basis for being a hazardous location.

 

I have not seen nor have I been able to confirm the existence of any of the letters, notices, guidance documents, or the like which have been said to indicate a less strict definition of what would be considered hazardous than the caveat in the method.

 

The belief I have encountered is that merely stating there is a hazard thereby makes it a fact and the regulatory agency would then have to show there was no hazard. This seems to have a fatal flaw in the logic as the intended new application of the term would be to remove all hazard, which is not possible. Testing is somewhat hazardous even with the in-stack filter and not significantly more so with the heated probe and filter.

 

One of the recent discussions finally ended when the agency agreed to abide by the determination of a state safety inspection of the facility to determine the hazard level of the facility test site. It seems the source did not want to be classified as a hazardous location for their workers and the issue was dropped.

 

As a result, I would recommend that attempts to replace the heated probe and filter be tied to some identified condition, the removal of which would have a significant impact in reducing risk of injury or death. A more frivolous or confrontational approach would seem to be counter productive in the long run.

 

Wayne Stollings

Triangle Environmental Services, Inc.

Wstollings@aol.com

 

P.O. Box 13294 122 US Hwy 70 E

Research Triangle Park, NC 27709 Hillsborough, NC 27278

(919) 361-2890 (800) 367-4862 Fax: (919) 361-3474

November 2017

Triangle NoTES

 

November 2017

 

I have been asked several times now as to whether our filter holders meet the specifications for Method 25. The answer is a simple, yes they do. Some have questioned whether we have actual Gelman filters or just an equivalent by another manufacturer because they did not look like the current model of Gelman filter being sold. For the sample consoles we produced, the filter holders were purchased through Fisher Scientific over two decades ago and were referenced as Gelman filter holders. We not only purchased the holders for our consoles, but also purchased a few which were modified to be used as an in stack filter and spare units for repairs. Since these are fairly robust filter holders with few points of failure, the last of the units were purchased in 1998. I cannot speak as clearly for the Nutech sample consoles as they were purchased as completed units, along with a few spare filter holders from Research Triangle Laboratories in the early 1990s. There are filters using the older Gelman design which are also currently available, such as the Advantec MFS holder.

 

We have posted a large picture of the inside of the filter box of the sample consoles we constructed on our website for reference. It shows the filter holder and the thermocouples to measure the gas temperatures as specified in Method 25. I have included the web address for the equipment page. The picture is at the bottom of the page. You can see the tee where the probe attaches with the exposed probe

thermocouple pointing to the left. The thermocouple for measuring the gas temperature going into the filter is a little harder to see as it is perpendicular to the camera in the tee attached directly to the filter housing inlet. As both of these measure the gas temperature, the temperature of the exterior of the probe and the surfaces of the filter box will be much higher in order to attain the correct temperature in the gas flowing through.

 

http://www.triangleenvsvcs.com/equipment/

 


This situation has brought about other questions concerning compliance with the method requirements and modifications to the method. Most of the modifications we have enacted are tightened QA/QC measures.

 

For example, we increased the size of the oxidation catalyst and slowed the flow to increase residence time for the sample because we were seeing incomplete conversion of the NMOC in sources where Method 25 had been used but which were not the initial target sources. The intent of the method was better met by this modification as the EMC agreed at the time. The lowered rate of flow does increase the time required to perform the trap recovery, but as there is already a substantial amount of time required to recover the trap following the method guidelines, this increase is not that significant and the resulting benefits far outweigh the added time. The procedures we saw at Research Triangle Laboratories when it was still in operation focused on the minimal amount of time for recovery and, I believe, as a result more potential errors were introduced than benefits. The use of the “warm purge” during the trap recovery to transfer some of the sample from the sample trap at ambient temperature to a second trap on dry ice seemed to introduce carryover between samples at times. Considering the specified flows would require hours for the sample tank and the Intermediate Collection Vessel (ICV) to reach the pressure required to perform an analysis this did not introduce a significant time saving process. Of course, there could be other modifications in addition which could reduce the time, but more and more such modifications make for more and more concerns considering the number of various sources for which Method 25 is used and more for which it could be used. We opted to have multiple recovery systems which allowed for an increased throughput and more efficient labor usage without more modifications.

We also bake out the traps and individually analyze each and every one at a higher temperature than is used for recovery to help insure there is less chance of carry over. The method only requires a completed recovery of the trap at 200 C to be used for later sampling, where we additionally bake them at 300 C and then QC them at 250 C.

 

We perform a QC analysis on each and every tank prior to use, which is not addressed in the method at all. We clean them with multiple series of evacuation and filling with air prior to being evacuated to <10 mmHg and leak checked, usually over night, to ensure they are not leaking. We have had tanks sent out at <10 mmHg and ~325 mmHg absolute pressures kept by clients for over six months with no change in the pressure by most of the tanks. A very small percentage will leak over that time, which is why we still encourage the tanks to be sent to the site under positive pressure to ensure any contamination possibility is a low as possible. Even though our leak check procedure is much more comprehensive, a field leak check is also suggested because we are dealing with mechanical seals which can fail without notice.

 

We perform a QC analysis of each and every sample console after we have cleaned and leak checked them to much more stringent requirements than the method requires. This helps to ensure they are more easily used in the field but also allows us to provide a Chain of Custody (COC) for the equipment to document the levels to which they were checked prior to shipment into the field. This COC can be retained and included in the field testing report if required.

 

These additional measures to the method are part of how we were able to pass the EPA audit at the lowest documented level, which was 50.2 ppmC. This was before the program was shut down in the hopes it could be privatized, which unfortunately still has not happened. Total audits are the best way to determine if there are problems with the sampling, analysis, or both as the pass/fail data has indicated in the past. From what I was told by the people following the audits, our record showed a marked improvement over prior audits, which resulted in a request to visit our facility to see what we were doing differently. The difference was just that we had returned to the method requirements and eliminated the modifications which had been introduced as undocumented improvements over time. I cannot speak to our audit statistics as I never monitored them due to the way the audit program reused some of the audit cylinders and my desire to eliminate even the suspicion that we could guesstimate the concentration. It is always possible to cheat if one desires, so we try to ensure there is ample documentation and cross checking to eliminate any question concerning our results. Our company reputation, the reputation of our employees, and my personal reputation is far too important for me to risk, which is why we take every effort possible to provide the best quality results possible.

 

I do not have any information on the 301 validation for the changes as that is being handled internally by the proponent of those changes. To my knowledge, he is handling all of the sampling and analysis comparisons to be turned over to the EMC for review.

 

Wayne Stollings

Triangle Environmental Services, Inc.

 

Wstollings@aol.com

 

P.O. Box 13294 122 US Hwy 70 E

Research Triangle Park, NC 27709 Hillsborough, NC 27278

(919) 361-2890 (800) 367-4862 Fax: (919) 361-3474

Triangle NoTES — February 2016

This newsletter is to restart my newsletter program, to give information on how to seal Tygon tubing to a barb fitting, and to update the ownership of TES.

Yes, this is a return to the use of the newsletter I have used for the last couple of decades.

After my email concerning the potential leakage using Tygon tube on barb fittings, a few of you reminded me of some of the other ways by which one could also secure the tubing to the fitting.

One prominent tester, who many would recognize if I mentioned his name, uses small electrical wire ties, which work great in their experience. We have also used the very small electrical wire ties to hold 1/8 OD tubing onto the air actuators used on on our analyzers. This is mainly to prevent the connection from separating due to pressure, but it also prevents leakage, which would be very noticeable. Of course the smaller the tie is in thickness the more flexible it will be, and the more flexible the better the seal it will ensure. This may be the best solution for ease of application, simplicity of operation, and resulting seal.

Another solution, which is more of an emergency or field expedient solution, is to use the wire from the tags like we send with the samples. A portion of the wire may be wrapped around the tubing a couple of times, either after or between the barbs, and then twisted together to prevent it from becoming loose.

The reason I have reinstated the former newsletter is that we are again an independent laboratory effective the first of February after seven months as part of Enthalpy/Montrose. I have always liked the role an independent laboratory can play in this industry and I am looking forward to returning to that view by everyone. Invoices and reports will now come from TES and TES only from this point forward. The prior invoices from Enthalpy/ Montrose should be paid to them.

Wayne Stollings

Triangle Environmental Services, Inc.

 

Wstollings@aol.com

P.O. Box 13294

Research Triangle Park, NC 27709

 

122 US Hwy 70 E

Hillsborough, NC 27278

 

(919) 361-2890

(800) 367-4862

Fax: (919) 361-3474