concrete

Discusses masonry walls in relation to the air tightness of buildings. Considers mainly panel walls constructed of concrete blocks. States that in general such walls are very leaky, due mainly to shrinkage of the wall itself and deformation of the surrounding structure. Discusses the addition of insulation to wall, sealing of joints around window frames and at the edge of the floor slab. Gives diagrams showing details of building construction.

Presents the air leakage characteristics obtained from measurements of nine brick and concrete block walls in the DBR/NRC huts at Ottawa and Saskatoon. The leakage characteristics of the first three walls were obtained in the Saskatoon test huts - the remainder were obtained in the Ottawa huts. All thetest huts had an overall plan area of approximately 6 ft. by 6 ft. The effects of fill-insulation and different surface finishes were determined.

Reports study of emanation of radon from concrete blocks enriched with uranium ore, placed in an airtight enclosure. The radioactivity of air samples was determined using a high resolution silicon diode detector system.

Reports first report from committee, "Preliminary proposals for measures against radiation risks in dwellings". Notes that prime source of radiation, alum-based lightweight concrete, has been banned in new buildings in Sweden, but is still present in 10%of pre-1975 houses. Provisional limits for gamma radiation for undeveloped sites: 30-100 micro.r/h (site should only be built on subject to other conditions), more than 100 micro.r/h (building inadvisable). suggests that geological radiation maps be charted. Notes reduction in radon content through house ventilation.