Submitted by Maria.Kapsalaki on Fri, 05/30/2014 - 12:50
In 1998, NIST published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the "myth" of the airtight commercial building (Persily, 1998). Since then, NIST has expanded and maintained a database of whole building envelope leakage measurements of U.S. commercial and institutional buildings.
Submitted by Maria.Kapsalaki on Thu, 10/31/2013 - 22:40
In 1998, Persily published a review of commercial and institutional building airtightness data that found significant levels of air leakage and debunked the myth of the airtight commercial building. Since that time, the U.S. National Institute of Standards and Technology (NIST) has maintained a database of measured airtightness levels of U.S. commercial building leakages, in part to support the development and technical evaluation of airtightness requirements for national and state codes, standards and programs.
For the building team, the design of library, archives and museum facilities brings with it special responsibilities. Archive and conservation facilities require the highest levels of preservation and maintenance of the building environment. Understanding how to maintain and preserve vulnerable materials is a key component to developing a successful design solution.
The building envelope is primarily an environmental separator, which allows indoor spaces to bemaintained at different conditions from the outside environment. Intentional humidification during the heating season is a common practice in cold climates. Moisture escaping from a humidified building due to air leakage through flaws in the air barrier system can negatively affect the durability of the building envelope.
Discusses what benefits there may be in employing an effective quality assurance program for building envelope air barrier systems, and what elements it should include. Proposes a protocol for inspection and testing of building envelope air barrier systems. Cites literature to highlight how testing has been shown to improve a building's air permeance.
This symposium covers materials, techniques and technologies successfully employed in energy efficient air barrier systems for residential and commercial buildings. Also looks at occupancy ventilation issues when developing functional energy efficient air barrier systems.
Describes the experimental evaluation of a brick veneer steel stud (BVSS) test specimen. The system was evaluated for air leakage characteristics, pressure equalization response, deflection and water penetration. Concludes that for best results for BVSS walls, the air barrier must be sufficiently airtight to achieve static pressure equalization and there must be sufficient venting to achieve dynamic pressure equalization. Similar results were obtained from research conducted on other wall systems.
Reviews the use of spray-polyurethane-foam insulation in buildings and discusses how their characteristics influence their field performance. Recommends that when used as an air barrier, polyurethane foam may crack on joints subjected to shrinkage or by structural deflection. To maintain the integrity of the air barrier, one should attach a strip of peel-and-stick membrane to both sides of the joint.
Discusses the importance of selling the cost benefit of tight building practices in the absence of national or local codes or regulations to mandate well-sealed apartment buildings. States that studies carried out by the Canada Mortgage and Housing Corporation have found that air leakage in apartment buildings can contribute to as much as 20% of the annual space-heating energy load. It also represents a substantial proportion of the peak space-heating load.
The National Building Code of Canada (NBC) requires that an "effective" air barrier system be incorporated within the building envelope. Although the NBC addresses the performance characteristics to be considered to demonstrate that an effective air barrier system has been achieved, the NBC does not prescribe any specific test protocols with acceptance criteria to verify compliance of proprietary air barrier systems.