Radon Levels and Indoor Air Quality in Northern Ireland Certified Passive House Buildings

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1 Radon Levels and Indoor Air Quality in Northern Ireland Certified Passive House Buildings CIBSE Technical Symposium London 2018 Thursday 12th Friday 13th April

2 Introduction CREST since 2013 Passive House Designer since 2014 PhD Studies in Passive House at Queens University Belfast Director of Passive House Association of Ireland Founding member of NZEB Ireland 15 years Experience in the Industry of Sustainable Construction and Renewable Energy

3 Passive House - Overview Passive House refers to the international Passive House Standard, sometimes also referred to using the German spelling Passivhaus. The Passivhaus standard was developed in Germany in the early 1990s by Professors Bo Adamson of Sweden and Wolfgang Feist of Germany. The first dwellings to be completed to the Passivhaus Standard were constructed in Darmstadt in Passive House is not a brand name, but a construction concept that can be applied by anyone and that has stood the test of practice. Passive House is the fastest growing energy performance standard in the world The Passive house standard can be applied not only to residential dwellings but also to commercial, industrial and public buildings. The EnerPHit Standard is also available for retrofit of buildings.

4 Passive House - Requirements The Passive house standard requires that the building fulfils the following requirements: 1. Total annual heating or cooling demand be less than 15 kwh/m²/yr. OR to be designed with a peak heat load of 10W/m² 2. Total primary energy must not be more than 120 kwh/m² per year. 3. The building must not leak more air than 0.6 times the building volume per hour (n / hour) at 50 Pa (N/m²) as tested by a blower door. There is a tendency from the industry to label or describe some low energy buildings as a passive house standard building when in fact they are not certified by the passive house institute. For a building to meet the certified Passivhaus standard, certain measured criteria must be meet and post construction testing is required to ensure that criteria have been satisfied. Passive house is not passive solar or passive-something, it is a defined standard. Elrond Burrell

5 Passive House - Principles Five Passive House Principles 1. Super Insulation 2. Thermal Bridging 3. Triple Glazed advanced Windows 4. Airtightness 5. Mechanical Ventilation with Heat Recovery

6 Passive House - UK First Certified Passive house building in the UK was in Since then there has been incremental growth of the standard. There have been a number of high profile projects including two which were featured in Grand Designs. There has been a growth in adaptation by some housing associations and also some council areas.

7 Energy Performance of Buildings Directive (EPBD) The European Energy Performance of Buildings Directive Recast (EPBD) requires all new buildings to be Nearly Zero Energy Buildings (NZEB) by 31st December 2020 and all buildings acquired by public bodies by 31st December Almost all near zero energy buildings will incorporate a fabric first approach to the building fabric this will mean increased u values and a significance increase in airtightness with most ventilation strategies changing from natural to mechanical heat recovery ventilation systems. The adaptation of these new building methods at large scale means that the emphasis on airtightness and better thermal building fabric is likely to increase; there is an incumbent need for research investigating the impact this on indoor radon concentrations.

8 Radon Gas Radon is a colourless, odourless radioactive gas. It is formed by the radioactive decay of the small amounts of uranium that occur naturally in all rocks and soils. Radon gas is classified in group one as carcinogenic to humans by the International Agency for Research of Cancer (IARC). Radon is estimated to cause between 3-14% of all lung cancers in a country, depending on the national average radon level coupled with occupant smoking prevalence.

9 Northern Ireland Pilot Study It is estimated to cause 30 deaths per year in Northern Ireland and is the second largest identified cause of lung cancer after smoking Public Health England (PHE) estimates that some 155,000 homes, or about 1 in 5 in Northern Ireland, are now in affected areas : these are places where some householders are exposed to radon at a level where protective action is recommended The objective of this study is to assess if a certified passive house building with much higher air tightness than other standards coupled with mechanical ventilation will produce reduced indoor radon gas concentrations and provide excellent indoor air quality.

10 Northern Ireland Pilot Study The sample used in this paper is from five certified passive house buildings located in Northern Ireland. The table below provides details on these buildings including the Size Year of construction, Construction type, The certification of passive house standard The air tightness level (n50). ID Postcode Year Size M 2 Construction Type Building N BT M 2 Timber New Build Detached n50 = 0.51/h 2856 BT M 2 Timber New Build Detached n50 = 0.58/h 4749 BT M 2 Masonry EnerPHit Detached n50 = 0.7/h 4751 BT M 2 Timber New Build Detached n50 = 0.6/h 5185 BT M 2 Timber New Build Campus n50 = 0.6/h

11 Northern Ireland Pilot Study Radon is measured in Becquerel s per cubic metre of air (Bq/m3). Radon measurements are normally made with two passive integrating detectors in each home - one in the main living area and the other in a regularly used bedroom. The numerical radon results are presented as: arithmetic average and geometric average. ID Postcode Homes Homes Arithmetic Geometric Highest Result Tested Average Average 2474 BT78 5 3, Bq m Bq m Bq m BT19 1 6, Bq m Bq m Bq m BT Bq m Bq m Bq m BT71 6 4, Bq m Bq m Bq m BT74 4 1, Bq m Bq m Bq m -3

12 Radon Monitoring The government has recommended an action level for radon in homes in the UK. This level is 200 Bq/m3. Above this level it is recommended that householders take action to reduce their radon levels The indoor radon levels were measured by CR-393 alpha track diffusion radon gas detectors placed in the main living area (Room 1) and the main bedroom (Room 2) for just over 3 months from October 2017 to January 2018.

13 Radon Monitoring In 2010 the Health Protection Agency (HPA) updated its advice on the limitation of human exposure to radon, maintaining the national action level at 200 Bq/m3 and introducing the concept of a target level at 100 Bq/m3 The Graph shows the arithmetic average comparison. We can see that all results indicate levels below the action level (AL) of 200 Bq/m3. ID: 4751 however is above the target level (TL) of 100 Bq/m3.

14 Radon Monitoring The Graph shows the geometric average comparison of the house monitoring results of passive house buildings when compared to the corresponding postcode reference level. We can see again that all results indicate levels below the action level (AL) of 200 Bq/m3. ID: 4751 again however is above the target level (TL) of 100 Bq/m3.

15 Indoor Air Quality Monitoring Temperature, relative humidity and carbon dioxide were monitored over the same three month period during the radon testing. The average temperature figures recording during the three month monitoring period maintain excellent thermal temperatures within a 20.7 C to 22.5 C although ID: 5185 had a peak recording 28 C above the threshold the figures are well within the limit of 26 C for 10% of the year specified by the Passive House Institute.

16 Indoor Air Quality Monitoring The average CO 2 air quality readings recorded qualified as good. It is acknowledged that the 2787ppm figure recorded in ID: 2474 is significantly high however this was elevated for only a short period of time and was directly linked to occupancy.

17 Indoor Air Quality Monitoring The relative humidity percentage in all the buildings display excellent readings consistent with good indoor air quality. Based on the results of this monitoring period the conclusion is that the Passive House standard achieves its stated objective providing occupant comfort and indoor air quality.

18 Pilot Study Conclusions The main results are consistent with the hypothesis that certified passive house buildings perform better. This clearly shows lower indoor radon concentrations in the passive house sample. As the number of houses investigated in this research was very small, the results should be treated with caution, This correlates with results in similar pilot studies.

19 Future Work Future work will produce a local comparative study of the certified Passive House standard buildings and buildings built to the prevailing building regulations in the UK and Ireland with respect to radon, and the differences quantified. Building characteristics such as construction type, airtightness levels and also the retrofitted home will be tracked to ascertain any statistical correlation between these factors, radon levels and indoor air quality.

20 Thank You for your Attention South West College