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Abstract: The capacity of drying out moisture accumulated within stud cavities, especially moisture due to rain penetration, is an important characteristic affecting the performance and durability of building envelope systems. This paper introduces a new approach for evaluating such drying performance based on the concepts and procedures of Limit State Design (LSD) used in structural engineering. For a well performing envelope, the moisture load must be less than the drying capacity of the system. The drying capacities are obtained through full-scale experiments that utilize moisture loading derived from a moisture source (water tray) placed at the bottom of the stud cavity. In moving out of the cavity, part of the moisture will be absorbed by the materials surrounding the stud cavity. When any part of the wall specimen reaches 20% MC, the cumulative evaporation from the water tray is termed as the ICEA (in-cavity evaporation allowance) of that wall system. The ICEA value is dependent on the envelope configuration and is a good indicator of the drying performance of that wall system. By comparing ICEA values of wall systems with their respective moisture loads, those envelopes having ICEA values higher than the amount of rain penetration calculated from prevailing driving rain and faults in the envelope are deemed to have adequate drying capacity. [ABSTRACT FROM AUTHOR]

Automating the checking of building envelope design according to design regulations is a complex process because these regulations consist of complicated logic sentences covering multiple functions. Existing mechanisms of building code computer-aided checking have some limitations dealing with design regulations. This paper presents a new integrated approach to automated code compliance checking for building envelope design based on simulation results and building codes. In this approach, building codes and simulation results are seamlessly linked with the compliance checking software. A hierarchical object-based representation of simulation results is proposed as an extended building information model (EBIM) to describe the attributes of a building and its subsystems. A representation of building codes based on decision tables and compatible with the EBIM is also proposed so that users can check the building envelope design against building codes based on the standardized simulation results. A prototype system is developed and a case study gives an example of evaluating the hygrothermal performance of an exterior wall. [ABSTRACT FROM AUTHOR]

The fan pressurization method for measuring air leakage through the building envelope relies on the assumption that the extraneous air leakage (EAL) through paths other than those through the specimen being tested is negligible. When EAL does exist, the calibration procedure by ASTM Standard E-283 is used to measure EAL values by covering the specimen or guarded chambers are used to equalize the pressure differences across these unintended paths. A new testing method, the flexible double-chamber method, is presented in this paper for large specimens where the above two approaches are difficult to implement and where flexible chambers are more easily applied. The experimental procedure and data processing routine are presented for the case of a full-size metal curtain wall specimen. The EAL is estimated by regression analysis in data processing. Inference analysis, multivariate error analysis, and the Monte Carlo simulation technique are also presented to examine the estimation errors. [ABSTRACT FROM AUTHOR]

During the detailed design stage of a building project, a vast amount of mostly interrelated design information is generated and communicated among specialists from several disciplines. Changes in some design information are inevitable due to the iterative nature of the design process. In many cases, when the design of a building component is modified by one discipline, this change affects the design of many related building components that are the responsibility of several other design disciplines. Commitment and resources are needed to accommodate such design changes to maintain compatibility among all the design information. Otherwise, incompatibility errors become embedded in the design information leading to numerous problems during the construction of the project. This paper presents a computer-assisted methodology that helps design managers in planning and scheduling changes with interrelated effects on the design information. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents a methodology for investigating the influence of three major parameters in the design of two-storey housing units in different neighborhood layouts, on solar energy utilization potential. The parameters are geometric shapes of individual units, density of units and site layouts. Rectangular and L shape with different values of the angle enclosed between the wings of this shape are studied. The density parameter is represented by detached and multiplexed units. The effect of parallel rows of units is also studied. Site layouts include a straight road and south and north facing semi-circular roads. The EnergyPlus simulation package is used to simulate 26 configurations consisting of combinations of the parameter values. Effects are evaluated as the change from reference configurations of the response parameters – incident and transmitted irradiation of facades and integrated PV electricity generation. The results indicate that the total electricity generation is governed by active roof surface area which is affected by both shape and orientation. Up to 50% increase in electricity generation can be achieved in some housing units of certain configurations, compared to the reference. Variation of surface orientation, particularly in curved layouts enables the spread of peak electricity generation over up to 6h. [Copyright &y& Elsevier]