Storm Shelter Missile Criteria - Wood Sheathing Criteria? 3

[echobs]

I am currently designing a Storm Shelter following the ICC 500. The building is roughly 36'x40'. I am using CMU walls and wood trusses spaced at 1'-4" o.c.

I am looking at the ICC 500 and I see there is a Missile Criteria in section 305. The design wind speed for this building is 200 MPH for tornados. Per section 305.1.1, "The missile testing for all components of the storm shelter envelope of tornado shelters shall be a 15-pound sawn lumber 2 by 4 traveling at the speeds shown in the table." In table 305.1.1, for a design wind speed of 200 mph a 15 pound 2x4 shall travel 90 mph on Vertical surfaces and 60 mph of horizontal surfaces.

Is there any criteria for roof/wall sheathing. Ideally, I would like to use 1/2" APA sheathing or 3/4" APA sheathing, but I do not know is these materials can take the required missile criteria as described in Section 305.1.1. I would like to use the required sheathing to meet these guidelines, but it seems there is nothing online or in the code(from what I have seen ) that describes this.

Do any of you have any thoughts or reference on what roof sheathing I should use?

 

[SJBombero]

The design of storm shelters is based on using rated assemblies tested per the guidelines of ICC 500. I have a report with the results of various test assemblies but I can't tell you for sure if the testing procedure meets all of the criteria in ICC 500. It gives a penetration speed for a 15 lb 2x4 missile for a large number of assemblies.

 

[STrctPono]

pvchabot is spot on! That is the best paper out there when it comes to impact missile testing. You will not finding anything more comprehensive. There are only 2 (possibly 3) wind cannons in the country and the only other one is in Hawaii and has been testing systems with lighter missile weights and lower wind speeds.

 

[echobs]

Thank you! I have seen some data from TTU, but I was not able to find a comprehensive overview. This document is extremely helpful.

I was also able to find more helpful direction in FEMA P-361, third edition Part B8. This section is a good reference to clarify debris impact loading and criteria.
Regarding the wood sheathing this is what I found... "Tests have shown that sheathing attached using wood adhesive complying with ASTM D3498 and code-approved #8 screws (not drywall screws) penetrating at least 1½ inches into the framing members and spaced not more than 6 inches on center provides sufficient capacity to withstand the tornado design wind loads if the sheathing is attached to the exterior surface of the wall studs." I am thinking using an assembly selected from the document from TTU provided by pvchabot that meets the required wind speeds and attaching it with this criteria should allow me to meet criteria provided by ICC 500.

 

[STrctPono]

echobs,

You also might want to look at your local building code and see if they have adopted or added amendments specifically for this requirement and have accepted particular assemblies.

 

[EdStainless]

I recall that some of door hardware people (hinges and locks) have extensive test data also.
I saw a neighbor's front door with four deadbolts (top, two on edge, bottom) and four or five hinges.

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