Chipboard is a common building construction material which continuously emanates formaldehyde. Reports measurements of concentrations of formaldehyde in 24 rooms in 23 Danish dwellings where chipboard was used for walls, floors and ceilings. Gives results in table 1 of concentrations underdifferent combinations of temperature, humidity and ventilation rate. Finds average concentration of 0.62 mg/m3 and in some rooms concentration exceeded the German threshold limit for occupational exposure. Develops mathematical model for the room air concentration of formaldehyde.
Explains method for calculating time dependences and average values of gas and particle concentrations in ventilated rooms, which permits determination of air pollution propagation in a room by means of given target functions. Applies method forvarious ventilation rates. Provides calculated example of determination of gas concentration occurring in a room with a leaky gas container. Illustrates representative time functionfor different pollutants.
Awareness has developed in the United States in the last five years that traces of radioactive radon gas and its daughter products are present in varying amounts in the indoor air. Reviews the existing literature in the subject giving a table showing reported radon concentration. Notes wide variation in results. mentions standards developed to protect uranium mines. Recommends research to quantify radon concentration data.
Reports study of the ways in which different ventilation levels affect people part 1 of the study took place in Gavle. Air change rates, the amounts of radon and its derivatives were measured. Finds that ventilation installations are often poorly adjusted giving a wide variation between flats in the levels of air change. Amounts of radon and daughters were also higher than expected, due mainly to the poor ventilation. Concludes that lowering ventilation to present recommended level of 0.5 changesper hour cannot be recommended without further investigation.
Describes background to natural radiation in building materials and particular aspects of radium decay which produces radon. Notes human lung capacity to absorb airborne particles and associated health risks. Illustrates diagramatically different particle sizes retained in various sections of human respiratory system. Suggests methods to avoid exposure to decay products: avoid materials with high radium content and maintain low radon concentration through sufficient ventilation. Graph shows concentration of radon in relation to air change rate.
States that the need for fresh air to dilute cigarette smoke is the dominant criterion for ventilation design. Reviews the literature of the subject and concludes that the three main health factors are carbon monoxide, acrolein and particulate matter. Finds very wide differences in sensitivity between people. compares IHVE guide of 1970 with the british standard draft code of practice CP3 concludes that cigarette smoke shouldbe treated as a contaminant and not linked with body odour dilution.
Discusses fresh air requirements and tolerable levels of contamination from various sources within a space. Explains the calculation of dilution rates. States that in summer the rates required will generally be higher than those derived from theinformation given because of the need to reduce temperatures in non-air-conditioned buildings and gives method for calculation of ventilation rate required.
Discusses toxic and flammable gases and vapours that lead to hazards in buildings. Examines trends in accidental deaths in the home in England and Wales from gas poisoning. Discusses influence of buoyancy on the dilution by ventilation air of accidental leaks of toxic and flammable gases and shows where buoyancy dominates layers can readily form. Presents theoretical results for controlling gas hazards in buildings by ventilation for a wide range of practical situations.
Points out that increased levels of thermal insulation in dwellings make ventilation heat loss an increasingly significant proportion of total dwelling heat loss and of great significance for sizing heating installations and selecting their control equipment. Treats attempts to reduce ventilation loss by specifying greater tightness of building structures, especially windows.
Analyses the problem of air management in energy conserving passive solar houses and discusses cost effectiveness of various alternative scheme. Use of polythene sheeting to form anair-tight membrane aims to reduce uncontrolled ventilation rate to 0.05 air changes per hour. Discusses problem of indoor air pollution and suggests adding venting windows and air-to-air heat exchangers. The need for internal air circulation is answered by ceiling fans or a central forced air system.
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