English

Fresh air requirements in individual rooms of an occupied house vary between 0.5 and 2 air changes per hour depending on the number and activity of the occupants. The most common method of ventilation control is by opening windows but measurements show that even quite moderate window opening results in air change rates greater than 2 air changes per hour throughout a house.< Reports measurement of the energy cost of window opening in a test house with a heat loss coefficient of 5 kWh/K day. Finds in a low energy house,controlled ventilation is essential.

The daughter products of radon are chemically active materials which, when inhaled are very likely to deposit in the respiratory tract. Defines a special unit, the working level, to indicate the radiation burden from radon daughters. Reports study of exhalation rates from various building materials made by enclosing samples in containers and analysing air samples from the containers. Gives table of results. Discusses control of airborne radiation by increasing the ventilation rate, sealing room surfaces, mechanical circulation and filtration of the air.

In some buildings in Canada ventilation systems are being operated with the outside air supply dampers completely closed during winter to reduce ventilation and hence conserve energy. Reports measurements of the carbon dioxide concentrations in the classrooms of a small elementary school, when the outside air-supply damper was closed, to assess whether ventilation was adequate. Concentrations were found to be well below the maximum accepted occupational standard of 0.5% and air infiltration gave an adequate fresh air supply.

CAFE is a suite of computer programs, developed by Atkins Research and Development, to solve engineering problems involving fluid flow and heat transfer. Based on a finite difference method, its main advantage over other programs is its generality, which enables problems requiring a variety of different boundary conditions to be studied.< Describes the mathematical formulation of the program and its major features. Gives examples of its application including modelling the ventilation of a building to reduce concentrations of dangerous gases.

Outlines in general terms the ventilation characteristics of typical British houses. Discusses energy losses through conduction and ventilation. Shows that excess energy consumption over that predicted theoretically can be partly accounted for by the British habit of opening windows. Reports program to investigate factors influencing the amount of window opening. Suggests new integrated approach to energy on the home.

Data has been obtained on the radon concentration in natural gas supplied to several metropolitan areas in the United States. The average value of 20pCi/l was selected to estimate the contribution of this source of natural radioactivity to doses from radon daughters received by individuals in homes. Radon daughter concentrations in the home atmosphere were calculated by use of computer programs for an 800 cu.ft. house in which 27 cu.ft. of gas per day was used for cooking in an unvented kitchen range.

Presents the results of an energy-efficiency survey of 25 homes located in Saskatoon, Saskatchewan. Insulation levels in the walls, ceilings and basements were measured and the economics of adding insulation to these areas were investigated. Air leakage of the houses was measured using a pressure test and compared with infiltration rates measured using tracer gas in fourhouses.< Concludes that a major portion of the heat loss (30-40%) in the average home was due to excessive infiltration.

Reports a series of tests of the air leakage of new homes built and sold in the Ottawa area in 1978. The homes were tested by depressurizing them to apressure difference of 10 Pascals. 80 tests were made involving 63 houses and 9 builders. The relative tightness of a house was defined as the volume rate of infiltration under 10 Pa divided by the area of the building envelope that separates the heated volume from outside conditions. Gives results with relative tightness of each house.

The potential for air conditioning energy savings using exhaust fans to cool attics was investigated in six occupied townhouses at Twin Rivers. These houses were compared with similar houses without attic fans. The houses had various levels of instrumentation. Data collected for two summer months in 1977 was the basis for this study. The principal quantities measured were attic and living space temperatures, air conditioner and attic fan usage,together with outside air temperature and solar flux.

Presents the results from a major airtightness survey carried out in Norwegian dwellings. 61 detached houses and 34 flats were pressure tested. In 14 of the detached houses and 6 of the flats, leakage paths were traced using thermography. Gives tables of results. Lists most common leakage paths located by thermography. Occupants of the dwellings were interviewed about draught problems, but there was no clear correlation between occupant dissatisfaction and leakage rate. Notes a considerable variation in leakage between the houses.