An In-depth Understanding of Sub-Slab Depressurization and Benefits of Installing it!

An In-depth Understanding of Sub-Slab Depressurization and Benefits of Installing it!

Environmental Screening Levels:

The Environmental Screening Levels (ESLs) highlight a range of contamination in soil, groundwater, soil gas, and indoor air and also the concerns regarding impacts to drinking water, vapor intrusion, and implications to aquatic habitat. It’s a regular method for screening levels found at various sites with contaminated soil and groundwater and in the end, distinguishing and assessing potential ecological concerns at contaminated sites.

Out of several mitigations approaches for preventing subsurface vapors, the most common active approach is Sub Slab Depressurization.

Sub Slab Depressurization –

The EPA explains the sub-slab depressurization system that can attain lower sub-slab air pressure comparative to indoor air pressure by use of a fan-powered vent drawing air from underneath the slab. That explains, even with different cracks or holes, or other pathways between the commercial building and the subsurface, the vapors will flow downward, not upward. Hence, a well-framed sub-slab depressurization system will, in all probability, keep any dangerous gases from meddling above into the building.

Let’s learn on the process:

Installing sub-slab-depressurization:

The sub-slab depressurization system installation involves creating holes in the slab, eradicating a little amount of soil from underneath the section to make a “suction pit,” and after that putting vertical suction funnels into the openings. The pipes are associated with a complex containing vapor & exhaust fans, which are thus vented outside. A large building needs more suction pits than the smaller ones.

The steps include:

  1. Pilot Testing
  2. Drilling
  3. Vapor Collection
  4. Installing Pipes
  5. Sealing 
  6. Venting
  7. Exterior Termination
  8. Monitoring


Sub slab ventilation systems are best to alleviate indoor vapors arising from subsurface contamination.

In recent months there has been a considerable increase in demand for custom sub-slab depressurization systems with control panels for vapor mitigation. The entire process is highly effective and considered everywhere. It is extensively measured as the most beneficial vapor intrusion mitigation strategy for prevailing and new buildings.

passive vapor mitigation system is also considered but is a little higher in range due to the high cost of maintenance.

Fulcrum Resources Environmental does an effective sub-slab depressurization system through:

  • Consistent Inspections
  • Analytical Measurements
  • Indoor air (IA) sampling

Recent changes in California Environmental Screening Level:

The changes to the screening Environmental Screening Level in California that work towards tightening down vapor interruption and other screening levels focused on:

  • cost of cleaning up a site as per the general inclination of administrative offices, and therefore moneylenders, will increase; and
  • Additional properties will be seen as environmental liabilities, consequently diminishing the estimation of the property and conceivably making potential purchasers pull back from the exchange and search for another property.

Changes to the Environmental Screening Levels have likewise brought about numerous groundwater ESLs now being lower than the State Maximum Contaminant Level, implying that at times, consumable water will be delegated a vapor intrusion hazard. It has been concluded after proper research on contaminants filtering from the soil into groundwater. This exploration has delivered refreshed information on contaminant solubility and Henry’s Law Constant. The followed leaching technique is the same and hasn’t changed.

You can request a quote mentioned on the website to know the sub-slab depressurization system cost or can fill in the Contact form for the service. We would be happy to assist you!

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