English

Measurements of the dynamic heat transfer in a four-bedroom townhouse were made under controlled conditions in a large environmental chamber to explore the viability of a computer program developed at N.B.S. labelled NBSLD for predicting heating and cooling loads and inside temperatures. Test house was factory-produced, of modular design and lightweight (wood) construction. Tests were performed with simulated outside summer, winter and autumn diurnal temperature cycles. Inside temperature was maintained at 75 f and the activities of a six-member family were simulated.

States that it is usual to assume a certain pressure difference across a window for a given wind velocity. Describes method of recording and instrumentation used to record wind speed and direction and pressure difference across two windows. Gives results of measurements showing dependence of pressure on winddirection. Shows that stack effect, even in buildings of moderate height, may be of sufficient importance to require a different allotment of heating capacity between lower and upper floors.

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.

Presents description of an automated, controlled-flow air infiltration measurement system. This system measures total air flow, a volume per unit time, due to infiltration in a test space. Data analysis is discussed and the mixing problem analysed. Different modes of operating the system are considered : (1) concentration decay, (2) continuous flow in a single chamber and (3) continuous flow in a multichamber enclosure. Problems associated with the use of nitrous oxide as a tracer gas are described.

Describes apparatus used to measure air leakage through walls, the types of walls and the test procedure. Gives results of tests on plain walls and shows the effect of adding plaster and paint. Concludes that infiltration rates of plain walls vary greatly. Of the three factors, affecting infiltration rates, workmanship is the most important, the composition of mortar next and the type of brick the least important. Finds that gypsum plaster stops almost all infiltration and that the application of paint reduces leakage.

When attempting to determine heating/cooling requirement of a home a difference in infiltration can drastically affect heating/cooling requirement imposed on air conditioning system. Describes "the super sucker" machine designed to depressurise homes so that infiltration can be measured under simulated windconditions and each area of leakage isolated. Illustrates machine photographically. Gives method of determining air change rates. Summarises test data for several homes which indicatethat infiltration could be effectively reduced by use of various caulking compounds.

Outlines parameters governing air infiltration. Discusses problem areas of house to house comparisons of air leakage. Deals primarily with tracer gas procedure as compared with pressurisation/depressurisation approach. Describes testing in townhouses of recent construction as well as in a number of older homes of varied design. Uses roof-top laboratory test chamber to examine relations between wind effects, buoyancy effects and building openings and how they effect air infiltration. Uses results to clarify evaluation of air infiltration.

Describes how in 1960-62 National Research Council of Canada conducted air infiltration measurements on 2 single-storey houses using helium as a tracer gas, followed in 1967-68 by measurement of air leakage characteristics using house pressurisation technique. Describes procedure developed from these tests for calculating infiltration rates. Gives equations for calculating infiltration due to stack effect and that due to wind action. Gives equation for combined effect.

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.

Presents and explains derivation of simplified heat transfer equation as part of an averaging method to enable perceptive home owner to determine air infiltration. A winter month isselected and the gas meter read daily. Explains how with these minimum data and summary data from us weather bureau average infiltration for the month, plus other useful data such as relative magnitude of conduction vs. infiltration losses can be determined. Demonstrates technique by worked example for a demonstration house.