VAPOR INTRUSION
VAPOR INTRUSION COATING. RETRO-COAT
The Retro-Coat™ Vapor Intrusion Coating System is a complete product line that consists of chemically resistant materials to properly protect existing structures from the threat of vapor intrusion without the need for additional concrete protection.
Developed by the Research and Development team of Land Science®, the Retro-Coat system has been subjected to rigorous testing procedures to prove its ability to combat the most aggressive chemical vapors.
The main component of the Retro-Coat system is the Retro-Coat coating which is a two part, odorless, no volatile organic compounds (VOCs), 100% solids coating.
Available in a variety of colors, Retro-Coat can be applied on damp as well as dry concrete, concrete masonry units, tile, brick, and metal.
For enhanced slip resistance, a suitable aggregate can be added.
In addition, other additives or materials can be utilized to achieve a desired performance or aesthetic look.
FREQUENTLY ASKED QUESTIONS
The following are the key questions for most VI investigations:
1. Do I have an indoor exceedance?
2. If “Yes”, is this from an indoor source or due to VI?
3. If due to an indoor source, can we identify this and resolve the issue?
4. If due to VI, where is it coming into the structure?
We answer each of these questions within a few days of monitoring combined with a few discrete samples. As such, once you have this data in hand, you can proceed to the next step of either mitigation or site closure.
We were not able to determine why TCE was not listed. TCE was not listed on the MSDS either. We’ve encountered similar situations with other materials. For instance, we recently encountered a disinfectant in the restroom at a facility where indoor TCE was detected. The container did not mention TCE, and the MSDS stated that it included “40% additional ingredients.” After an analysis in the field, we determined that it did contain TCE.
This is something that OSHA has not yet caught up with. Given all the products on the market that include TCE, we will continue to be vigilant about this. Having the analyzer on-site has helped, as we were able to resolve the issues while in the field without having to wait for a fixed laboratory result.
Since we can track conditions continuously, the consultants we have worked with have observed the initial data generated including spatial and temporal patterns, and then intentionally induced building manipulations to evaluate cause-andeffect. This includes turning the HVAC on and off, covering drains, sealing cracks, and tracking differential pressure, which is the main driver for concentration
“spikes”. With these observations, consultants have been able to convince their regulators to move the project to the next phase in the life cycle of VI management. As such, they’ve been able to proceed based on a single mobilization.
Yes, continuous monitoring is becoming more prevalent as practitioners see the large benefits it offers. EPA has required it on 2 thermal remediation sites to monitor for off-gassing. MA-DEP has required it on construction sites to monitor fugitive emissions. In many cases, regulators cannot require it, but they recommend it. Every agency appreciates the data because you get hundreds to thousands of data points and can see the picture much better than from a few canister or passive data points.
Both methods are flawed. At sites we have monitored both sub-slab and indoor air and we see large variations in the indoor air but little variation in the sub-slab. This does not provide actionable data to find a remedy. When using our system, the data shows what is really going on which allows you to take immediate actions to find remedies.
Radon gives a much more realistic value for the attenuation factor than the ultra-conservative default value of 0.03. I collect radon data whenever I do sub-slab sampling.
Yes, it would show repeated measurements of both indoor air & sub-slab soil gas so that one can see if they change together. We have not done many sites with both indoor air & sub-slab data, but the limited data to date clearly shows that indoor air fluctuates much more than sub-slab soil gas, hence the attenuation factor is not constant.
It can be used on BTEX sites. We have to be careful with BTEX sites that we can get resolution of benzene or speciation of benzene from cyclohexane, but yes, it can.
Yes, Groundswell Technologies has used the system on residences. Quite often, it’s too expensive to use on a single residence, but in the pictures Mark showed, they were in a neighborhood, they were able to run tubing to several residences, three or four or five at one time, so that made it cost-effective. We’ve also been in large residences with lots of rooms where it was cost-effective. So yes, we have done residences, but most often, we do commercial structures.
The barriers that Land Science provides, especially the metallized films, are performing at such a high level for preventing vapor intrusion that we’re taking it to that next level in taking a third-party lab to do the analysis for mercury. And we’re confident, once we get the data back, that we’ll be able to provide that quantitative information for regulatory approval or just industry requirements. But in the interim, we do have an internally published letter that we can provide indicating why TerraShield and MonoShield would be viable barriers for mercury vapor intrusion.
With regulatory agencies, some accept it and some don’t. As far as California goes, two members of DTSC gave presentations on it recently, and in both those presentations, they said radon would be a good line of evidence to use to determine a slab-specific building specific attenuation factor. I don’t know the policy of the water boards, whether they do or don’t agree. My recommendation to practitioners is collect the radon data anyway, it’s very inexpensive. It’s another line of evidence that you can use. Some agencies or cubicles may agree with it, some may not, but it’s so inexpensive to collect. It’s worth doing so and it’s certainly better than using a default 0.03.
Yes, it has. What we do is we oftentimes are asked to look at the sub-slab at the same time as indoors. Obviously, in the sub-slab, we would expect a higher concentration, and so we may try to run a blank before we start to monitor indoors following a sub-slab sample, but yes, we do that.
Several years ago, the U.S. EPA issued a memorandum and a lot of state regulatory have also followed suit to an extent. With 30 mils, both on the construction aspect and scientific aspect for diffusion, has been identified to be the more appropriate barrier minimum, and that’s one of the reasons why Land Science developed MonoShield, and when we designed it, we released it as a 30-mil barrier, meeting not only the construction standard, the integrity of being able to hold up to the construction of the building, but also diffusion tests, the solution being 30 mils or thicker.
The other thing they need to think about is if you’re looking or considering 20 mils, you have to think about how protected are you with the seams. A lot of the 20-mil systems out there are taped together. And if you’re only as successful as your weakest link, the tape is your weakest link, and you may still have a concern with tapes in the 20 mils.
Yes, it can. And the alerts can be set up to be universal, meaning that say that you want to look at 10% of the LEL anywhere, or you can look at a specific location, you can set up a different rule for that. So it’s very flexible the way it’s been designed. Also, that the system can measure very, very low, down to the ppm level, or can measure very high, up at the percent level.
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