Nitrile or nitrile-butadiene rubber (NBR) has an abundance of properties that make it an ideal material to be utilized in barrier systems that prevent subsurface contaminants from migrating into the indoor airspace of buildings. It has good abrasion/tear resistance, good compression set, resistance to heat, water, and chemicals. But let’s take a close look at why nitrile has become of key importance to the vapor intrusion mitigation industry.
Gas Permeability and Chemical Resistance – Why Nitrile is So Protective
Many synthetic rubber production companies rate Nitrile’s gas permeability as good. Its gas resistance depends on the level of acrylonitrile which is commonly referred as the ACN content. The typical ACN content ranges from 14% to 50% because the more acrylonitrile included in the copolymer, the resistance to oil and gas permeation increases; however, the higher the ACN content, the lower the flexibility of the rubber. Ergo, the common ACN content percentage for the nitrile to have low permeability while still being flexible is 36%. The possible reason for the good gas permeability is that when butadiene and acrylonitrile are combined in the mixing process, the two polymers react to each other a create strong cross-linked valent bonds. These bonds leave little room for most gases to pass through, except for ozone, ketones, esters, and aldehydes.
So it makes sense that nitrile can be of tremendous value to the vapor intrusion world. The primary goal of practitioners in this industry is to protect human health by blocking contaminant gases from migrating from a subsurface source into the indoor air space of a building.
An acknowledged weakness in many vapor barrier systems is in the slab penetration and perimeter termination locations, where spray-applied core material composed of Styrene-Butadiene (SBR)- modified asphalt is used. While excellent at repelling water, aggressive chemicals such as petroleum solvents and chlorinated volatile organic compounds (VOCs) will permeate into the SBR-modified asphalt at a relatively high rate, particularly in these vapor intrusion sensitive areas of the building construction.
The Research and Development Scientists at REGENESIS and Land Science know this, and that’s why they developed Nitra-Seal.
Nitra-Seal offers a substantial upgrade as it employs a more chemically resistant nitrile latex instead of the more susceptible SBR material. Nitrile, due to some of the reasons explained above, is recognized throughout the environmental engineering industry as being more chemically resistant than rubber or SBR and is often used in personal protective equipment when working on hazardous waste sites (e.g. nitrile gloves). Laboratory testing has shown up to 10X higher chemical resistance when compared to any other spray applied vapor barrier material on the market.
If you’ve been to a doctor’s office lately, you’ll likely see that the gloves sitting there on the counter are no longer latex; they’re nitrile. Physicians offices have moved away from latex and to nitrile gloves. Why? Because not only is nitrile more chemically resistant; it’s more durable too.
So the R&D team at Land Science again applied this concept when they were developing Nitra-Seal. With vapor intrusion regulatory standards becoming ever more complex and stringent, there is an emerging need in the industry for better, more reliable protection against contaminant vapor intrusion.
This is why nitrile is so valuable. It will provide better protection, and that protection will be more durable and reliable due to puncture resistance. Nitra-Seal forms a highly puncture resistant barrier that greatly reduces the chance of damage occurring after installation and prior to the placement of concrete.
The added value brought by nitrile’s durability provides a critical advantage with new building construction.
Nitrile can be applied as sheets or as liquid depending on what it needs to be applied to. For instance, if nitrile rubber is needed to seal plumbing, then liquid is required; but if an entire floor needs to be sealed then nitrile sheets are the best option. There is no need to lose sleep over whether nitrile will leave even a sliver of a crack on the application site because Nitrile can fit into any nooks and crannies of any site where it is spray-applied, including seams and penetrations of a vapor barrier base layers. In the end, once a site is sealed, there is an excellent chance that the seal will last for years without letting gas permeate or being severely damaged.
When the other layers of the Nitra-Seal system are combined with its spray-applied Nitrile-based core to seal all seams and penetrations, the end result is a barrier that is highly resistant to a broad range of chemical pollutant vapors.
Nitrile is a versatile material that is utilized in many different applications, from sealing gas pipes to providing doctors protection in gloves. But it’s also especially valuable to the vapor intrusion mitigation industry, due to its low gas permeability, chemical resistance, and easy application.