Torben;

Their old FL product approval states Purlins

Alton;

the old Actech plant?

Posted By cmkavala on 10 Feb 2011 01:54 PM

Posted By wild01 on 10 Feb 2011 01:02 PM

so with a 6" thick panel I could install a ridge beam down the center of a structure and and span 10' to an outer wall on a 6x12pitch leaving me a 12.8' span and have a snow load of >30 psf

thats a pathetic span capability

so what is the max span of your 6" thick metal sip with a 30psf snow load

Chris,

Alternative Construction Technologies (ACTech) has new owners.  It is now called Green Product Technologies and the name of the panels have been changed to G-SIPS.  My understanding from talking to the new leader (Stephen V. Williams), the panels did not change.  I belive this company produces only 3" thick, metal-skinned, polyurethane-filled type of panel.  At least that is the only type that I saw when I toured their plant in Bolivar TN.

wild01;

16 ft. in the flat

Alton;

yes 3" thick, walls and roof, 24" wide with fasteners inside and out at seam

I like G-SIPS but it does take some time and effort inserting all of the screws every 2' to hold the joints together.

Chris, I looked and see where you are talking about this in their 2007 product approval. In their 2004 approvals for walls and roof there is no mention of purlins.

Chris, It seems you may be comparing wind uplift with snow loading. From what I've seen the Kingspan panels have slightly more span capacity the the EPS panels.

Torben;

the wind uplift is 33#

Chris,
it appears that your panel has a 2' greater span than a kingspan panel, I fail to see why that would make a kingspan panels span capability pathetic, thats pretty close

Posted By wild01 on 11 Feb 2011 01:50 AM
Chris,
it appears that your panel has a 2' greater span than a kingspan panel, I fail to see why that would make a kingspan panels span capability pathetic, thats pretty close

16 minus 10 = 6 ft.     60% greater span is significant

Chris, I posted the span table for the kingspan panel. a 6"panel @30 psf can span up to 14 feet. then I posted the example of what I was trying to do to show that yes the kingspan panel would work for me.
hence the statement

a 12.8' span and have a snow load of >30 psf

> means greater than

I also realize that on a slant their panels can probably span greater distances than they can on the flat, however around here the building inspector frowns on the word probably, so I used worst case scenario. not the 10 feet from structure center to outer wall, but the 12.8 feet from peak to outer wall on a 6x12 pitch roof-this was done on purpose!! I had one span table, so thats what I used.

There is no 60% difference in span capability between panels. I'd be shocked if there is even a 10% difference in strength. The strength is in the steel edges and they are both 26 gauge. Any steel SIP has excellent span capability and strength to weight properties. The strength is in the steel and the foam mostly just holds the high strength skins in place. To any extent the foam does make a difference the edge goes to poly panels not EPS since it has an approximately 4 times greater shear strength. When I've seen span tables actually comparing the same loadings I've seen the poly panels very slightly outperform the EPS. I think anybody who needs that extra is designing foolishly close to the limits.

Torben;

calculated with a safety factor of 2.5

wild01;

it is not probably    ...   actual panel in the slope is longer (17'-10") than the horizontally measured span of 16'-0"

Posted By cmkavala on 11 Feb 2011 09:00 PM
Torben;

calculated with a safety factor of 2.5

I believe the 2.5 factor has to do with panel failure and perfect connections.  Significant creep is going to occur long before that.

Posted By cmkavala on 11 Feb 2011 09:14 PM
wild01;

it is not probably    ...   actual panel in the slope is longer (17'-10") than the horizontally measured span of 16'-0"

OK, cool did not know code calculated span based on the horizontal measurement. so w/king span I could build up to a 28' wide structure and with your panels I could go up to 32' wide. (and still meet my local snow load of 30 psf.) so your panels have an aprox. 14% better span capability rating than theirs.

Posted By wild01 on 11 Feb 2011 01:30 PM
> means greater than

10 feet from structure center to outer wall, but the 12.8 feet from peak to outer wall on a 6x12 pitch roof-this was done on purpose

this post says your horizontan span is 10 ft.?

Panels are not tested on the diagonal. One should use the horizontal measurement up to a 5/12 slope. 6/12 slope and above should use the diagonal clear span distance. Otherwise one is defeating the safety factor. None of the manufacturers seem to address this issue.