To: teric(--nospam--at)gk2guam.com, seaint(--nospam--at)seaint.org
Subject: Re: "Pre-Engineered" Metal Buildings
Date: Wed, 9 May 2001 14:41:31 EDT
I worked in metal buildings for several years and since leaving the PEMB
business I have written specs for many pre-engineered metal builidings since
then. I thought I would point out what I have encountered since my days in
that area. Definitely read #2 and #5 below if you are associated with a
PEMB on your project.
1. The term Pre-engineered meant they designed a specific size building for
1 or more existing codes. That design was "shelved" and resused anytime
someone requested the same building under one of the codes it was designed
for. It was like buying a shirt. "Give me a 34 Long". They are actually
re-releasing the design/drawings because the design parameters are identical.
Drawback is when there is a flaw in the original design. In the old days,
the Client did not have much options for size, bay spacing etc. "The Client
had to pic from what was on the rack." Currently, most all large PEMB
companies design per order thanks to the Demon Computer.
2. Reputable PEMB stamp their own building designs. I caution you to make
sure you be cautious if requiring them to meet AISC. Section 4.2.1 (page
5-229 in the green book) states OWNER's approval constitutes acceptance for
all design responsibility. I generally require them to meet AISC except for
that section which I reword to place responsibility on them. "Ever wonder
why some of the low-end ones seem to care less if their design is adequate?"
This is one of the reasons, it is your butt not theirs. I think this
subsection was originally meant for local fabricators making simple shear
3. If you are reviewing a set for a company with no stamp in your state, be
sure you really check it. You would be surprised where the lower end
companies get their "design ideas". If you are not familiar with PEMB
components and systems, get some help.
4. As far as local requirements, I have never been anywhere that accepted an
5. ALWAYS require a "Letter of Certification for Loading" from the supplier.
This is a letter that ceritifies what it was designed for and what codes it
meets. Look for words like "in accordance" and " as specified" and avoid
wording like "used as a guideline" or "as a model". Some of the letters are
not worth the paper they are written on. This letter should be stamped by
As I stated, I work in metal buildings for several years and do not see
anything wrong with the concept or components. The problems generally are
with the individual companies. I work for Butler for 5 years and we
occasionally review our competitor's designs. We were constantly trying to
figure out how their steel is stronger and spans further than ours could.
Generally, it was design differences.
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
* send to the list is public domain and may be re-posted
* without your permission. Make sure you visit our web
* site at: http://www.seaint.org