Due to concerns about potential airborne chemical and biological
(chembio) releases in or near buildings, building owners and
managers and other decision makers are considering retrofitting
buildings to provide some degree of protection against such events.
A wide range of technologies and approaches are being proposed with
varying levels of efficacy and cost, as well as varying degrees of
applicability to particular buildings and ventilation systems. This
document presents the results of an effort to evaluate chembio
retrofit options for buildings. A number of retrofit options are
identified, and their potential to protect building occupants from
a number of generic contaminant releases is evaluated using
building airflow and contaminant transport modeling. In addition, a
case study is presented in which specific retrofit options were
considered for two actual buildings and pre-installation designs
and cost estimates were developed. Based on the analyses performed,
the results of the case study and other available information,
guidance on the application and effectiveness of various retrofits
are presented. An economic analysis software tool employing life
cycle cost analysis techniques was developed as part of this
project, and its use is described in an appendix to this report.
The retrofit options considered fall into two categories, the first
being stand-alone technologies or devices such as enhanced
particulate filtration that are installed and implemented as
purchased. The second category includes retrofit approaches that
employ operational strategies or building modifications to increase
building protection, such as outdoor air purging or building
envelope tightening. The guidance section describes each retrofit
technology and approach in some detail, presenting relevant
performance data and the level of protection that might be expected
from the retrofit. Potential disadvantages and knowledge gaps are
also discussed for each technology. The retrofit technologies
considered include enhanced particle filtration, sorbent based
gaseous air cleaning, ultraviolet germicidal irradiation,
photocatalytic oxidative air cleaning, and work area air capture
and filtration equipment such as mail handling tables. The
approaches include ventilation system recommissioning, building
envelope tightening, building pressurization, relocation of outdoor
air intakes, shelter-in-place (SIP), isolation of vulnerable spaces
such as lobbies, system shutdown and purge cycles, and automated
HVAC operational changes in response to contaminant sensing. The
filtration and air cleaning options are noted to have an advantage
of always being operational, which is an advantage as long as the
systems are properly designed, installed and maintained. However,
the lack of standard test methods for sorbent-based gaseous air
cleaning and other air cleaning approaches is identified as a
critical impediment to the application of these technologies.
Building envelope air sealing and pressurization can be quite
effective in protecting against outdoor releases as long as
effective filtration against the contaminant of concern is also in
place. The protection provided by operational changes such as
system shutdown and purging are shown to be very dependent on the
timing of their implementation, with the possibility of increasing
occupant exposure if the timing is inappropriate. Isolating
vulnerable zones and other system related modifications are highly
dependent on the building layout and system design, and their
implementation must be well conceived to be effective under the
range of conditions that exist in buildings. Finally, many
retrofits are noted as also providing additional benefits of
increased energy efficiency and improved indoor air quality, which
need to be included in the life-cycle cost comparison of different
options to the degree possible.
General
Imprint: |
Createspace Independent Publishing Platform
|
Country of origin: |
United States |
Release date: |
November 2013 |
First published: |
November 2013 |
Authors: |
Nist
|
Dimensions: |
280 x 216 x 10mm (L x W x T) |
Format: |
Paperback - Trade
|
Pages: |
184 |
ISBN-13: |
978-1-4937-5643-8 |
Categories: |
Books >
Arts & Architecture >
Architecture >
General
|
LSN: |
1-4937-5643-5 |
Barcode: |
9781493756438 |
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