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.
Defines ventilation requirements for spaces intended for human occupancy and specifies minimum and recommended air quantities for the preservation of the occupants health, safety and well-being. Recommendations are given for different rooms in alltypes of building in terms of the outdoor air supply per minute. Also gives maximum concentrations of various contaminents. States that outdoor air requirement can be reduced if air is recirculated, purified or odour or gas removal equipment used, but in no case should be less than 5 c.f.m per person.
Notes that reduced infiltration and ventilation rates in buildings can lead to higher levels of indoor air pollution. Discusses three indoor-generated pollutants : nitrogen dioxide, formaldehyde and radon. Suggest ways of circumventing increased health risks without compromising energy conservation considerations, including setting standards for minimum levels, filtering recirculated air and sealing source material.
U.S. ventilation systems have been reported to require as much as 50-60% of total energy consumed in buildings and have become popular targets for energy conservation methods. Notes serious concern that arbitrary changes to codes and standards are being proposed in the name of energy conservation which could jeopardise health, safety or welfare of building occupants. Traces evolution of ventilation codes and standards in us.Treats difficulties encountered with measurement and direct control of indoor air quality. Notes common guide values for air contamination used.
Suggests many ways of reducing outdoor air admitted to a building. Notes importance of measuring minimum air flow to ensure adequate ventilation. Suggests measuring the concentration of CO2 in indoor atmosphere and using the results to control incoming ventilation. Describes simple and inexpensive implementation of the technique.
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