Ventilation is a key factor in low energy housing and in temperate maritime climates such as Britain's moisture is a major factor in determining ventilation needs. Outlines necessary levels of humidity for both people and buildings. Summarises sources of moisture. Discusses control of humidity by either mechanical ventilation or heat pump dehumidification.
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.
Recommends method for determination of extra heat and moisture load of a cold room resulting from leakages through chinks, cracks and porosity. Recommends clause on maximum leakage in delivery conditions. Treats internal and outdoor influences on air exchange, leakage detection and leakage measuring methods.
Describes the results of a major study to find out whether or not wall insulation installed without a vapour barrier causes an increased risk of moisture damage within walls. The exterior walls of 96 homes in Portland, Oregon were opened. Presents results of field and laboratory tests which show the absence of indications of moisture damage. Gives data on shrinkage and settling of insulation and results of air leakage measurements by fan pressurization tests. Concludes that the addition of wallinsulation without a vapour barrier does not cause moisture damage in existing homes.
Reports tests made to examine moisture problems in a flat roof of cold deck construction. Tests simulated the effect of normal, wet and very wet conditions below the roof with no ventilation of the roof. Found that without ventilation there is a substantial risk of moisture degrade and condensation problems. Roof was then ventilated at five air changes per hour and this was found to be effective in solving moisture problems. Suggests this as a minimum ventilation rate and that where it is difficult to provide ventilation in a flat roof, a warm deck design should be considered.
Reports experimental investigation of moisture content of bathroom air during and after a shower. Describes test apparatus and procedure. Gives graphs of dry and wet bulb temperature, relative humidity and absolute humidity for various mechanical ventilation rates as functions of time. Gives results of measurements of tracer-gas decay rates for various mechanical ventilation rates. Presents theoretical model for calculations of moisture content in air in bathrooms and finds excellent agreement with experimental data.
The building industry has always had considerable difficulty with joints in outer walls, at windows, doors and between building units. Damage caused by damp has meant considerable economic losses. New building methods and materials and stronger requirements in the indoor climate have accentuated the problem. Discusses use of fibreglass strips as a sealing agent. These can accommodate large movements in the joints, but the hermetic sealing properties are insufficient if there is a heavy damp load on the joint. Glass combined with plastic sheet can increase the hermetic sealing.
Calculations of water vapour flow through walls and ceilings are frequently based on the permeability of building materials and implicitly assume that most of the vapour transport takes place by diffusion. Finds that this model is generally inval
Reviews the requirement in building regulations for cavity barriers in roofs. States need for providing ventilation in the cavities of certain forms of roof construction,particularly those with a continuous waterproof vapour barrier to avoid moisture build-up. Examines how adequate air movement can be provided in both new and existing flat roof voids, designed with or having installed cavity barriers.
Login