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August 24, 2004
Radon Source and Entry Evaluation Name removed for client confidentially Condo
Naples, Florida
Preliminary report

The overall goal of this radon consulting assignment is to determine the source, entry mechanism, and possible driving forces causing elevated radon levels in the various upper floor condominium units in the Name Removed Tower 16 story-building complex. With this information it will be possible to determine the extent of the risk and potential liability arising from elevated radon levels in the complex’s apartments and also to collect some of the data necessary for the design of a radon mitigation system. The investigation and data collection began on August 20, 2004. A review of the building plans and specification was not within the scope of this assignment.

Measured Radon Levels
The radon test results indicate elevated radon levels in all sample apartments on floors 1 through 15, the test results for floor 16 may indicate possible ventilation during the test or the A/C may have been off. Detailed testing with continuous monitors in units 1201 and 104 indicates radon levels similar to the other tests. The ground floor south guest suite and unfinished kitchen area had levels well below 4.0 pCi/l. All of the radon testing results are contained in table 1. These radon test results are for diagnostic purposes and some of the testing does not follow Florida DOH protocol for residential radon testing.**

Radon measurements were also made in the halls adjacent to apartment 1201 and 104 with elevated results. A pair of radon test devices was placed on top of the drop in panel in the south elevator with results below 4.0 pCi/l. This eliminates the elevator installation as a major radon source.

Gross Gamma Radiation Measurement
Gross gamma radiation measurements were taken on the concrete floor surfaces in apartment 1201, 104, south guest suite, and the unfinished kitchen area with similar elevated readings in the range of 18 mR to 16 mR; the average for Florida outdoors is 6.8 mR.

Radon Soil gas Measurement
The radon soil gas levels were measured at locations adjacent to the south, west and north side of the building with all results below 20 count per minute with a W. Johnson Radon Sniffer - Detector and 18” soil probe. The unfinished kitchen area was tested at several plumbing block outs with the same equipment and had results in the 40 to 60 CPM range, a low reading for soil radon gas. These levels of radon soil gas are not consistent with indoor radon levels in the range measured throughout the project.

Interior Pressure Differentials
Relative pressure differentials were measured between the interior of apartment 1201 and the outside. With the A/C system operating the apartment is in a slightly pressurized state, this would be expected with the external location of the A/C utility room. The utility room is under negative pressure due to the un-ducted return air design. The radon level in this utility room area was slightly above the main area of the apartment indicating a possible source for radon from the open drain system. This is also a source for excessive moisture pick up by the A/C system. Radon can be drawn into any area of negative pressure. The existing return air system may also present challenges to the efficient operation of an ERV radon mitigation strategy.

Radon Flux (Emanation) from Concrete Surfaces
Testing for concrete slab radon flux was conducted on apartment 1201 AC utility room floor and on the ceramic tile floor surface inside the unit, on the slab in the unfinished kitchen area floor slab and on the vertical concrete column surface. A RadElec H E-Perm propriety test method was utilized. There are no existing standards or data relating to radon flux and to indoor radon levels.

Radon Flux From Concrete
Location net radon flux pCi/sq M/sec range found in other building with elevated radon
Apt 1201 utility room 0.304 0.150 - 0.750
Apt 1201 tile floor 0.0 increase NA
Unfinished area 0.502 0.150 - 0.750
Column face 0.133 0.150 - 0.750

The evaluation did not discover a source of radon soil gas consistent with the measured indoor radon levels. A major contribution from some of the concrete building materials is suspected. Elevated indoor radon levels were not present in the ground floor areas tested as well as inside the elevator shaft enclosure.

A system to mitigate the radon utilizing Energy Recovery Ventilation (ERV) technology may present some challenges due to the A/C system design.


& Apt #
Radon pCi/L
1201 A/C  room K181 10.6 10.6  
1201 A/C  room K182 10.6    
1201(B) MBR K183 10.2 10.2  
1201(B) MBR K184 10.3    
South Elev top K185 2.5 2.5  
South Elev top K186 2.4    
S Gnd Flr Unfin area K187 0.8 1.0  
S Gnd Flr Unfin area K188 1.2    
1507 LR K189 7.7    
1607 LR K190 2.7    
1407 LR K191 6.8    
1207 LR K192 7.7    
1107 LR K193 9.7    
1007 LR K194 11.7    
907 LR K195 8.1    
807 LR K196 8.4    
607 LR K197 9.7    
507 LR K198 8.5    
307 LR K199 6.7    
107 LR K200 4.4    
1201 LR CRM 8.5    
104 LR CRM 8.0    
S Guest RM CRM 1.5    
S Hall X 1201 J161 6.4 6.5  
S Hall X 1201 J162 6.6    
S Hall X 104 J163 3.9 4.0 A/c off ??
S Hall X 104 J164 4.0    

** the radon test results shown in this report are intended only for use within the scope of this analysis, some radon tests were placed and retrieved by non-DOH certified individuals.

Post report note:

One of the subject units was successfully mitigated to acceptable radon levels utilizing an Energy Recovery Ventilation system and AirPro pressurization techniques by Radon Mitigation Services, Geneva FL 800-344-3746, others are scheduled for the future /WL

Associated Radon Services has provided radon testing, entry analysis and mitigation design consulting since 1990 and is:

Florida DOH Radon Measurement Business Certification RB1654 Florida DOH Radon Measurement Specialist Certification R 1269

Florida DOH Radon Mitigation Business Certification RB 1406 Florida DOH Radon Mitigation Specialist Certification R 1318

National Radon Proficiency Program Certified Residential Measurement Provider 100217 RT

National Radon Proficiency Program Certified Residential Mitigation Provider 100739 RMT

National Radon Proficiency Program Certified Radon Analytical Laboratory 101095 AL