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Re: "Pre-Engineered" Metal Buildings

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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 
connections.  

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 
unstamped drawing.   

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 
their engineer.

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.  




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