window

A sequel to the report "Air leakage through the openings in buildings", abstract. no 286. Reports investigation of the effect on air leakage of increasing the clearance around a sash window. Gives results of experiments in the form of graphs showing leakage for different wind velocities, different clearances, and with and without weatherstripping.

Describes apparatus used to measure air leakage through windows. Gives details of windows with and without weatherstripping. Gives results in the form of graphs in two sections. 

The amount of air leakage through window gaps in buildings depends on the width and length of the gaps, the pressures across the buildings and the resistances in the air circuit. Reviews the ranges of these factors for Britain and gives results of measurements within these ranges for standard metal and wooden windows and for weather-stripped windows. Gives two methods of estimating the air flow through gaps in complete windows.

Describes apparatus and test method used for measuring air leakage through metal windows in the laboratory. Gives results for different types of windows and summarises air tightness standards in Japan and other countries.

Describes research project which aimed to quantify the difference between actual dynamic ventilation rates and natural ventilation rates predicted using a steady state model. 

Describes tests made on fifty different weatherstrips. Tests were made in the laboratory of airtightness, rigidity, ageing, load tests, freeze tests and wear tests. Strips mounted in windows were tested for ageing and resistance to driving rain. Gives test methods and results and discusses the characteristics of eight main types of strip.

Describes plan to retrofit 25 townhouses at Twin Rivers evaluating retrofits by instrumenting each house to record energy consumption, temperature, window and door opening and furnace operation. Aim of the first round of retrofits was a payback period of no more than three years. Describes fourretrofits A,B,C and D. A,C and D improved attic and cellar insulation and insulated the heating system. B aimed to limitthe amount of air infiltration from cracks around doors and windows by weatherstripping. Early results showed gas savings of the order of 25% and electrical savings of 10%

Shows need for intermittent high ventilation in dwellings to remove water vapour and odours. Suggests openable windows as the simplest and most common method of ventilation control. Gives air-change-rates in two british houses using carbon dioxide andnitrous oxide as tracer gases, showing the effect of opening windows. Shows that increase in ventilation rate caused by opening windows can be tenfold and is not confined to the room with the open window. Closing of internal doors has a significant effect. Describes investigation of air flow within rooms using smoke.

Discusses variations in the test results which occur with the laboratory procedures for assessing the air and water penetration attributes of windows. Presents data for windows examined under British Standard BS 4315 : part 1 "Methods of test for resistance to air and water penetration - windows and gasket glazing systems". Considers the implications of thesetests for the development of performance levels for use in standards and procurement documents, and proposes a two-stage statistical procedure, based in the first instance on tests on five windows.

States that ventilation needs can be identified from a study of people's behaviour. Reports results of regular systematic observations of open windows in a group of scottish houses which confirmed earlier work in Britain. Finds that the number of open windows is a direct function of outdoor temperature or moisture content and was also influenced by air speed with a smaller number of windows being opened in windy weather. Large families opened their windows more frequently than small families. Suggests that moisture control may be the main motivation for opening windows.