English

Reports study of the emanating power of radon from building materials. Samples of material were placed in an air-tight glass container and the radon diffusing from the sample was measured in an electrostatically operated cylindrical steel chamber in which alpha particle scintillations were counted.< Gives main results for different building materials in the form of anemanation coefficient, defined as the ratio of migrating 222Rn to the 226Ra content in the sample. Materials tested were fly-ash, slag, by-product gypsum, red brick, silicon brick, portland cement, and soil.

Reports a program of research in progress at the Colorado State University to determine the surface pressures on building models immersed in a simulated atmospheric flow. Pressure data on a model building is taken from 272 tappings and reduced to pressure coefficients. Reports pressure coefficient measurements have been completed for 23 building/boundary layer combinations.

Reports measurements of Radon-222 concentrations, carried out in the living rooms of 81 dwellings in Great Britain in 1976. Measurements of the activity concentration of RaA both within the room, and of the ventilation rate for the room were made. From this an estimate of the "radon output" of the room was calculated. Gives histogram of the radon outputs in picocuries of radon 222 per litre of room air per hour. Disregarding a very high measurement in a granite dwelling, the mean was 0.54 pCi/l/h.

Reports a nationwide investigation of gamma radiation in Swedish houses, made by the National Institute of Radiation Protection in Stockholm. The occupants of 2000 apartments and houses were picked at random and asked to participate in the investigation. The measurements were made with thermoluminescent dosimeters CaSO4 - Dy in teflon. Three detectors were sent to each of the selected dwellings by post. Finds that the accuracy of the detectors is about+ or - 25%.

Reports investigation of the radon concentrations in Swedish homes. The concentrations of radon and daughter products, air change rate and gamma levels have been investigated in 63 dwellings in seven types of houses built at the beginning of the 1970's in the town of Gavle. Gives table of results. From these results the absorbed dose in the basal cells of bronchial epitheiuim in the lung has been calculated for various periods.

Reports investigation into the radon dose from inhaled radon daughters during exposure indoors. The initial phase of the investigation comprised detailed measurements of radon daughter concentrations in each of four locations in the New York area. The investigation has now broadened considerably. Time-integrated measurements of radon concentrations and working levels have been obtained in twenty dwellings in New York and New Jersey in a two year period with which to estimate annual mean exposures of the inhabitants.

Describes a method of measuring airborne concentrations of radon daughters which distinguishes between the different isotopes. At the place of sampling, air is flowed through a millipore filter for five to ten minutes at approximately 12 litres per minute. The filter is counted during the period 2 to 12 minutes post sampling; the counts are integrated over each of four regions of energy and a second count made for the same regions during the period 15 to 30 minutes post sampling. Results are analysed by a BASIC computer program.

The authors have developed a Fortran IV computer program for estimating whole body and lung dose equivalent rates due to naturally occurring radionuclides in building materials. Two of the inputs to this program are the effects of wall thickness and the effects of a surface sealant on the gamma exposure ratedue to the increased quantity of radon daughter nuclides trapped within a wall.

Reports study of the exhalation of radon from building materials by following the build-up of activity in closed vessels containing samples of the material. On the basis of a linear diffusion model, the porosity, diffusion length and radon production rate were found for a light-weight concrete by measuring theexhalation at various, constant pressures. The exhalation of radon from wallswas measured in a concrete-walled basement room by studying the growth of activity in exhalation cans sealed to various portions of the walls.

Describes apparatus used to measure full-scale wind loads on a glasshouse. Wind pressure was sensed by a Dines anemometer and the variation in wind velocity with height by a small pressure tube anemometer. Wind loads on the glasshouse were sensed by pressure tapping points connected in sequence to micromanometers. Describes apparatus for the recording and analysis of data. States apparatus has been used for two years and found to be reliable in operation.