Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

Julien SYRENGeological engineer

Radon department manager, CRIIRAD laboratoryjulien.syren@criirad.org

Study carried out with the financial support of the Rhône-Alpes region

Radon andearth tubes

Radon etpuits canadiens

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

Operating principle of earth tube

Outsideair

Temperate air after passing

through the floor(connected to a

ventilation system)

Condensate drainHeat/Cold transferbetween ground and air

2 000 earth tubes installedin France in 2008

(LOYAU Frédéric, « Puits canadien et ventilation basse énergie », L’inédite,

2009)

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

1/ Case study : office building

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

1/ Case study : office building

a/ Preliminary surveys (march-april 2009)

First floor office : 339 Bq/m3

Double flux air handling unit (downstream earth tube and dust filter) : 684 Bq/m3

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

1/ Case study : office building

b/ Study of the ventilation system influence (summer 2009)

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

1/ Case study : office building

c/ Looking for radon sources (summer 2009)

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

1/ Case study : office building

d/ Remediation (winter-summer 2011)

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/20162/ Tests in 11 buildings (2009-2011)

7 individual houses3 office buildings1 day nursery / leisure center

Earth tube causesradon accumulation in the building

Earth tube doesn’t causeradon accumulation in the building

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/20162/ Tests in 11 buildings (2009-2011)

Solutions

• Seal the air leaksDrôme (building 1) : -60% (340 Bq/m3

140 Bq/m3)

• Prefer overpressure to depressionLot-et-Garonne : -70% (150/200 Bq/m3

50 Bq/m3)

• And… think to radon risk before constructingDrôme (building 1) : 1000 Bq/m3 (after earth tube) / 340 Bq/m3 (floor office)Drôme (building 2) : 80 Bq/m3 (after earth tube) / 52 Bq/m3 (floor office)Distance between 2 buildings : 150 meters

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016Conclusion

PROBLEM :Depression + air leaks radon accumulationRadon sources : tubes, gaskets between tubes, condensate drain, dry wellEarth tubes can cause radon accumulation even in places where radon potential is low

SOLUTIONS :After constructing : difficult but possibleBefore constructing : betterThe most important : raise awareness of radon risk to all earth-tube stakeholders (manufacturers, professionnal or « do-it-yourself » installers)

Radon and earth tubesCRIIRAD / J. SYREN

CRIIRAD – ROOMS 2016 – 06/10/2016

Thank you for your attention