In the last decade, public awareness of the greenhouse effect has pushed the building sector toward higher energy efficiencies. This move has had consequences for roofs with a cathedral ceiling. AU-factor in the vicinity of 0.2 W/(m2·K) instead of 0. 6 W/(m2· K) became the new target value. The move toward such a low U-factor for cathedral ceilings was evaluated in an extended test house program.
This paper describes a residential research facility built for the experimental measurement of the relative energy and moisture performance of various residential building envelope components and systems. The building comprises 12 test bays on an east/west axis bounded on each end by a guard bay. The eastern six test bays are framed in steel, and the western six bays are framed in wood. Each half of the building contains a symmetrical mix of vented and unvented cathedral and attic roofing systems and is built above a heated basement.
Canada Mortgage and Housing Corporation (CMHC) conducted a series of attic research projects from 1988to1997. Initially, there were few field test data to substantiate how attics dealt with air and moisture transfer. The CMHC research developed a test protocol for attic airtightness and air change testing and then proceeded to field testing of a variety of attics in different climatic areas. An attic model, ATTIX, was referenced against test hut data and used to simulate attic performance across Canada.
The heating, ventilating, and air-conditioning (HVAC) system for a laboratory must be designed with consideration for safety, air cleanliness, and space temperature. The primary safety concern is to ensure proper coordination between fume hood exhaust and makeup air supply. Air cleanliness is maintained by properly filtering supply air, by delivering adequate room air changes, and by ensuring proper pressure relationships between the laboratory and adjacent spaces. Space temperature is maintained by supplying enough cooling air to offset the amount of heat generated in the room.
Containment of hazards in a laboratory chemical hood is based on the principle that air drawn through the face area of the hood is sufficient to overcome the many challenges at or near the opening. Challenges to overcome include, but are not limited to, air velocities near the hood, movement of the researcher, people walking past the hood, location of equipment inside the hood, size of the sash opening, and the shape and configuration of entrance conditions. To overcome these challenges, a sufficient face velocity must be maintained.
This paper addresses atria smoke management systems where it is intended that occupants will be in contact with smoke. While this approach is unusual, it is recognized by several authoritative publications on atrium smoke management. A tenability analysis for an atrium smoke management system needs to account for the effects of ( 1) exposure to toxic gases, (2) exposure to elevated temperatures, and (3) smoke obscuration. Much of this paper consists of adapting and presenting well-established tenability methods for application to smoke management.
This paper discusses the numerical study of the effectiveness of atrium smoke exhaust systems. This study is part of a project initiated by A SH RAE and the National Research Council of Canada (NRCC), in which both physical and numerical techniques were employed to determine the effectiveness of such systems and to develop guidelines for their design. This paper presents numerical predictions obtained using a computational fluid dynamics (CFD) model and compares the numerical results with the experimental data obtained from tests performed in this project.
This paper presents results of a project initiated by ASHRAE and the National Research Council of Canada. The project applies both physical and numerical modeling to atrium smoke exhaust systems to investigate the effectiveness of such systems and to develop guidelines for their design. In this paper, results were obtained from a series of tests conducted using a large-scale physical model.
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