IEA_AARST_Radon_Reporter_JUNE_2024

THE RADON REPORTER | 21 RESEARCH Results Case Studies Presented below are three (3) examples of different case studies that support and provide evidence of why Pressure Field Extension testing is necessary prior to system design and installation. FIGURE (1): MICHIGAN BUILDING 1 FIGURE (2): MICHIGAN BUILDING 2 Figure (3) at right shows the building of concern. The outlined areas represent the five (5) unique building zones. PFE testing was done in each zone to determine the ROI. Red Zone: This zone featured compacted native soil. The data collected showed a 20-foot ROI at 12» w.c. applied and a 10-cfm airflow yield. Blue Zone: The soil profile in this zone was loose, sandy soil. The data collected showed a 30-cfm ROI at 12» w.c. and a 10-cfm airflow yield. Purple Zone: Crushed stone was observed beneath the slab, which generally results in high airflow yields. The ROI completely covered the room (in excess of 50 feet) with only 1.8» w.c. of applied vacuum and a 40-cfm airflow yield. Orange Zone: The orange zone represents an area of the building that rests on an isolated slab restricting sub-slab communication with the remainder of the site. Yellow Zone: This area featured soil settling around the building perimeter resulting in elongated ROIs along the wall but diminished ROIs into the center of the room. These ROIs were achieved by applying a vacuum of 12” w.c. and a 10- cfm airflow yield (as in the Red Zone.) Case 2: Building Constructed in Stages Pressure Field Extension testing was performed on a single 25,000 square foot warehouse with multiple additions located in a suburb of New York City. The data collected from the PFE testing indicated that each addition had different ROIs as a result of soil types and settling along the perimeter walls. Case 1: Side by Side Buildings At right (Figures (1) and (2)) are diagrams of two, nearly identical buildings constructed side by side, approximately 100 feet apart, in rural Michigan. Data collected from the buildings showed completely different ROIs. Data collected in Building 2 indicated a 12-foot ROI produced at 30 inches of water column (“w.c.) of applied vacuum with a resulting 5 cubic feet per minute (cfm) airflow yield. Building 1 data indicated a much greater ROI of 55-feet given 8 “w.c. with a resulting airflow yield of 30 cfm. The results of the PFE testing resulted in drastically different designs with Building 1 featuring a single, high airflow blower paired with a 5 suction point mitigation system and Building 2 requiring approximately 840-feet of horizontal drilling and 2 high vacuum mitigation blowers. FIGURE (3): NYC SUBURB BUILDING ZONES