German

Various ventilation systems have been examined in unoccupied test houses under natural climatic conditions. Two identical test houses were used to enable comparison of the effects of different ventilating systems on the air change rate and heat consumption. The systems examined were natural ventilating devices placed in the window area and centralized and decentralized mechanical systems. With the decentralized systems, draughts were generally unavoidable. Heat recovery from exhaust air at an air change rate of 1.0 h-1 gave a measured heat consumption saving of about 16 per cent.

Describes a procedure for the approximate determination of air infiltration for a single family house for given weather conditions. To carry out the calculation it is only necessary to measure the permeability of the building envelope using a blower door. The calculation procedure is so straightforward that it can be carried out on a programmable pocket calculator. Refers to a comparative study by the Air Infiltration Centre, which found that the calculation model described gave the best results of any single cell model for all the houses investigated.

The installation of much tighter windows has led to reduced rates of natural ventilation in German dwellings. This has resulted in increased indoor air humidity and condensation formation on the inner surfaces of external building elements with thermal bridges. Notes the areas most at risk from condensation and mould, in particular corners of outside walls and along the ceiling angle.

The increasing number of heat recovery devices in ventilation systems for residential buildings leads to the necessity for a standard test procedure. In this paper the main examination criteria are stated. The test facilities todetermine the efficiencies and the air leakage of heat recovery devices are specified. The test procedure used is described. Results from different heat recovery units indicate the suitability of the developed test equipment.

Energy conservation in dwellings has been realized mainly by tight windows and by improving heat insulation. Increasing damage to the building fabric by humidity and mould has been noticed. But there is no correlation between this damage and the improved insulation. Rather it is caused by too low ventilation rates. This paper deals with these problems in detail. Ventilation rates in the order of 0.5 to 0.8 per hour are assumed to be sufficient to avoid detrimental effects for the building and the inhabitants.

Three blocks of flats on the outskirts of Worms were equipped with a mechanical ventilation system with heat recovery, a mechanical ventilation system, and stack assisted natural ventilation, respectively. Building description, air quality, air change rate, draught protection, noise level, energy balance, individual heating costs, efficiency calculations, planning and installation experience and user behaviour were studied. Systems with heat recovery were found to permit a 15-20 per cent reduction of heat consumption. User behaviour in opening windows is dependent on habit.

This study investigates the structure and availability of ventilation systems in domestic housing. A measurement programme of natural ventilation efficiency was carried out and evaluated. Mechanical ventilation systems were compared. Their suitability for efficient ventilation of various house types is discussed.

Discusses the findings of a nationwide radon survey carried out in W. German houses. The average radon concentration in 6000 houses is 40 Bqm/m3. Treats the incidence of radon in the environment, its sources, the consequences of inhalation of radon, physical processes in room air, and methods of radon measurement.

Outlines the foundations for calculating and designing natural ventilation: conditions for the building unit: technological prerequisites: components: sound insulation: calculation methods: fields of application: combination of mechanical and natural ventilation: and models for optimization of new buildings and for reconstructing factories.

Natural ventilation has a specific significance in creating a tolerable environment in manufacturing plants with high technological heat loads. Equations for the calculation of natural ventilation for single storey industrial halls are derived from the mesh procedure, as well as other solutions for other buildings. Guidelines are given for the draught-free introduction of supply air. Reference is made to other design possibilities for the natural ventilation of buildings.