Technical Booklet C Site Preparation and Resistance to Contaminants and Moisture·Page 17·3.12
Radon Protection Requirements by Risk Zone
Northern Ireland requires different levels of radon protection based on the probability of radon exceeding the Action Level in a dwelling, ranging from no protection for 0-1% probability to Zone 2 measures (membrane plus subfloor depressurisation) for 10% probability and above.
The level of protection required in Northern Ireland is given in Table 3.1.
Radon risk shown on the radon map referred to in para 3.7 (probability of radon in a dwelling exceeding the Action Level) | Radon protection required
0 - 1% | No protection required
1 - 3%, 3 - 5% and 5 - 10% | Zone 1 measures (radon membrane required)
10 - 30% and greater than 30% | Zone 2 measures (membrane plus provision for subfloor depressurisation e.g. a sump and stub duct)
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