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Building Code History:
Historically, there have been 3 model
general building codes in the US. They
are "model" because they have no legal
authority. They are an attempt to
standardize safety and building
materials and standards throughout the
US. Before these existed, each legal
jurisdiction would write their own Code,
possibly by persons lacking in
engineering expertise.
The agency in each jurisdiction
(city, etc) that has legal or regulatory
authority or responsibility for building
safety writes their own building Code,
or adopts one of the model building
codes. In modern times, most
jurisdictions do not write their own
Codes but have adopted one of the model
codes, sometimes with some modifications
for their local requirements. Politics
often come into play.
The three model building Code
agencies are:
-
ICBO (International Conference
of Building Officials)(http://www.icbo.org),
publishers of the Uniform Building
Code (UBC). They are based in
Whittier, California.
-
SBCCI (Southern Building Code
Congress International, Inc)(http://www.sbcci.org),
publisher of the Southern Building
Code (SBC). They are based in
Birmingham, Alabama.
-
BOCA (Building Officials and
Code Administrators International,
Inc) (http://www.bocai.org),
publisher of the BOCA Code. They are
based in Country Club Hills,
Illinois.
The Wind and Earthquake provisions of
these Codes is of primary interest to
pressure vessel designers.
ANSI A58.1 and ASCE 7, Minimum Design
Loads for Buildings and Other
Structures:
Where does ASCE 7 fit into this picture?
ASCE 7 is not a model building Code,
but a national standard published under
auspices of American National Standards
Institute (ANSI). ANSI is not an agency
of the Federal government but is in
effect the quasi-official technical
standards setting organization in the US
(http://www.ansi.org/public/about.html).
Originally, the document was
published as ANSI A58.1 with the same
title. ASCE was generally responsible
for maintaining the standard and with
the 1988 revision the document was
issued as ASCE Standard 7 with date 1988
(ASCE 7-88). The document was revised
and republished in 1993, 1995 and 1998.
The document provides methods of
calculation of minimum design loads
resulting from the effects of Dead
Loads, Live Loads, Wind, Earthquake,
Snow, Rain, Icing, Soil, and the various
combinations thereof.
Some Editions of ANSI A58.1 and ASCE
7 were used as the basis for various
editions of the model building codes,
often with some editorial or technical
modification or simplification.
ASCE 7-98 was written with the IBC in
mind. As such, it incorporates much more
"code language" and is written in an
enforceable manner; ie: more of
"whereas", "wherefore", and "shall" sort
of language.
ASCE 7 does not address vortex
shedding, fluttering, and other dynamic
effects of wind. For vortex shedding,
COMPRESS refers to the National Building
Code of Canada (NBC-Canada).
IBC 2000 - International Building Code-2000:
To further standardize building codes throughout the US, the three model building code organizations jointly
formed the International Code Council (http://www.intlcode.org/abouticc.htm)
in 1994. The goal was to establish a single model building code for use in the US without regional limitations.
The new resulting model Code is the
International Building Code. The first
year of issue was 2000. This model Code
supersedes the UBC, BOCA, and SBC. Thus,
there will not be any new editions of
these Codes. Reference to these three
model Code organizations (through their
web sites) indicates that all three have
adopted the IBC and will no longer
publish their individual model Code.
Note that SBC was never incorporated
into COMPRESS and BOCA was dropped in
the Windows version although our dialog
has an inactive option for this
selection.
IBC-Wind:
The IBC-2000 incorporates ASCE 7-98
by reference in the Code. The Code
references ASCE 7-98 but also specifies
some additional criteria that will not
apply to pressure vessels. Thus it
should be fairly simple to incorporate
IBC-2000 into COMPRESS for Windows.
Alternatively, our customers should
realize that they can design per
IBC-2000 for wind by specifying the ASCE
7-98 'Code'.
IBC-Seismic:
Unfortunately for Codeware, IBC-2000
does not adopt ASCE 7 for seismic loads.
The IBC-2000 code incorporates the
methodology from NEHRP, the National
Earthquake Hazard Reduction Program.
However, this paper by S. K. Ghosh
provides helpful paragraph by paragraph
comparison of ASCE 7 and NEHRP: http://www.skghoshassociates.com/sk_publication/nehrp-asce-table2.PDF.
A search on the internet for both
"IBC +NEHRP" will provide a wealth of
additional resources.
NFPA - National Fire Protection Association (it is now officially the "NFPA"):
NFPA (http://www.nfpa.org/Home/AboutNFPA/index.asp)
is based in Quincy, Massachusetts. They
have long published model Codes for fire
and electrical safety. They publish the
important National Electrical Code
(NEC).
NFPA has somehow gotten into
disagreement with the International Code
Council and is in the process of writing
their own, competing, model building
Code, NFPA 5000. This model Code is
under development and has not yet been
published. Publication is anticipated in
2002 (the next publication of the IBC
will be 2003).
In an article at http://www.nfpa.org/BuildingCode/News/Articles/NaturalDisasters/natural_disasters.asp,
it appears that NFPA 5000 will
incorporate ASCE 7 as the basis for both
wind and seismic (what edition of ASCE 7
is unspecified). Thus there should be
minimal effect upon Codeware if our
customers want to apply this code.
Summary:
It appears that eventually IBC should
be incorporated into COMPRESS since it
is the replacement for the other model
building Codes. I don't know if there is
any urgent time frame for this. We
should probably see what our customers
ask for. I wouldn't be concerned with
NFPA 5000 since that can be covered with
ASCE 7.
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