Introduction to Aerated Floor Systems for Vapor Intrusion Mitigation

Transcription

1 2 nd Southeastern States Vapor Intrusion Symposium Introduction to Aerated Floor Systems for Vapor Intrusion Mitigation Atlanta, GA April 28, 2016 Justin Knight, P.E.

2 Agenda Vapor Intrusion (VI) Conceptual Site Models and Mitigation Tools Introduction to Aerated Floors Cupolex Geosyntec s Role Case Study Take Away s Questions 1

3 2 VI CSMs

4 Many mitigation tools, though many ways to do it right (or wrong) Barriers Sub-slab depressurization/venting (SSD/SSV) Vertical venting & pressurization barriers Aerated flooring Building pressurization Sub-slab pressurization Membranes and seals Indoor air treatment (activated carbon) Passive, active or semi-passive options 3

5 Example: Sub-slab depressurization Sub-slab depressurization most effective, if: - Dry, permeable soils - Lack of subsurface obstructions Grade beams Varied slab elevations - Intact slabs - Narrow building footprint - Single story buildings Fan Advective flow - P 4

6 Introduction to Aerated Floors - Cupolex A plastic form used to create a continuous void space below concrete slabs. Patented Concrete Forming System 100% Recycled Non-Toxic Plastic Little to No Additional Cost to New Building Construction 5

7 Introduction to Aerated Floors - Cupolex Long Track Record Invented by Pontarolo Engineering in Italy circa 1990 Over 600 million SF installed world wide Installed at 5 USAF bases in Italy Introduced to the US in late 2000s Sold in Italy, Germany, Spain, Austria, England, France, Portugal, Greece, Poland, Romania New Zealand, Australia, Africa, Russia, Brazil, Costa Rica, Canada, Mexico and the United States. Italian Federated Police Academy 6

8 7 Introduction to Aerated Floors - Cupolex

9 Introduction to Aerated Floors - Cupolex Traditional Sub-Slab Depressurization Radius of Influence Minimum - P e.g., Gravel, sand 8

10 Introduction to Aerated Floors - Cupolex Aerated Floor Sub-Slab Depressurization Radius of Influence Minimum - P Open void 9

11 Introduction to Aerated Floors - Cupolex Advantages Can be designed to be preemptive, passive, or active Open air space an optimum environment for dilution and/or active/passive removal Uniform differential pressure across the entire slab footprint Does not require certified contractors to install High strength and high load bearing structures Little or no additional cost to new building construction 10

12 Introduction to Aerated Floors - Cupolex On average, 2 laborers set 1200 sf/hr 11

13 Introduction to Aerated Floors - Cupolex Item Cupolex Traditional System Forms 1.75 NA Concrete (5 equivalent) same same ¾ clean gravel (12 ) NA 2.50 Welded Wire Mesh 0.30 NA Steel NA 0.75 Liner NA Perforated Pipe NA Not calculated Total $2.05/SF $5.25 $7.25/SF Additional savings can be realized with reduced concrete volumes and more efficient forming, resulting in no additional cost over standard floor. 12

14 Geosyntec s Role Contributed to the development of design procedures for VI applications Leaders of the industry with the most Cupolex aerated floor systems designed and installed Typical Role: Design, Train and Oversight, and Post-Installation Testing 13

15 14 Venting Design

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18 17 Riser Pipe Detail

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20 19 Air Transfer Pipe Detail

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23 22 Typical Utility Penetration Between Cupolex Forms Detail

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25 Case Study Performance of an Active Aerated Floor Vapor Intrusion Mitigation System in a Large Building 24 Tyler Junior College Tyler, TX 23,000 sq ft building Benzene plume underneath Geosyntec s role Design an active aerated floor (Cupolex) Train site workers to install Perform leak testing Project goal Mitigate potential benzene vapor intrusion

26 Case Study MP-1 Individual Cupolex Form 100 MP-2 Over 5,000 Cupolex forms installed 4-inch cast iron riser pipe Allows venting of void space 25

27 Case Study PHOTO 2: Cupolex forms installed over building footprint with complex geometry. Cupolex Beton Stop Prepping for concrete 26

28 Case Study Leak Testing and Evaluation of Vacuum Distribution Radon Away fans RP-140 (~135 scfm at 0-in WC) RP-265 (~334 scfm at 0-in WC) Differential pressure readings collected at two locations and riser pipe Measuring Point Distance from Suction Point (ft) Vacuum Readings Static Vacuum with RP-140 (in WC) Static Vacuum with RP-265 (in WC) Riser Pipe MP MP

29 Take Away s Understanding your site s VI-CSM is critical to every VI investigation and selection of mitigation tool There are many VI mitigation tools Select the best one for your site-specific needs and do it right! Cupolex works! Uniform vacuum with minimal extraction points and fans (if even necessary) Over 600 million sq ft installed world wide in last 20 yrs Easy to install No certified contractors required Cost savings due to reduction in concrete, gravel, steel 28

30 29 Questions?