archaic precast gypsum plank roof deck 4

[samdamon]

I am trying to determine the fire rating and uniform load capacity of an old roof deck system called Pyrobar. Need to replace damaged portion of it on a flat roof of an old building. The roof deck consists of a flat deck of 3" solid Gypsum planks 1' wide and 3' long supported by doubled light gage channels, in turn supported by structural steel framing. The planks are not poured on site but precast. There is a hung ceiling below which may be part of the assembly. The building may date from the late 1930's. Google has not been of much help. Any insight or experience appreciated.

 

[msquared48]

http://workshopoftheworld.com/southwest_phila/us_gypsum.html

Mike McCann, PE, SE (WA)

 

[msquared48]

http://vintageadsandbooks.com/unite...-1931-pyrofill-roof-vintage-catalog-z600.html

Mike McCann, PE, SE (WA)

 

[JAE]

Pyrobar is mentioned in this article:

http://www.structurearchives.org/article.aspx?articleID=753

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[TehMightyEngineer]

Be aware that these things hold up very poorly if not kept away from moisture and chemicals. I see systems like these a lot in old industrial facilities and occasionally the gypsum is extremely brittle with little capacity.

Maine EIT, Civil/Structural.

 

[msquared48]

As it turned out, the product was duscontinued because too many clients were gyped.

Mike McCann, PE, SE (WA)

 

[Ron]

I know I shouldn't encourage Mike....but....

Mike...good links...thanks.

 

[SlideRuleEra]

Here is the thirty-one page, 1919 Pryobar Catalog that included detailed thermal properties of the product:

https://archive.org/details/PyrobarGypsumTile

On the left side of the webpage you can download a .pdf version (free).

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Ron]

Another great example of SRE's value to this site!! Keeper of tons of info!

 

[samdamon]

Thank you all for your comments and links, and the engineering humor. Very helpful. Regards