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J. Peter Jordan (Unregistered Guest)
Unregistered guest
Posted on Thursday, August 11, 2011 - 10:04 am:   Edit PostDelete PostPrint Post

I am working on an existing facility that has a structural clay tile (the old unglazed type we used to use instead of CMU) which will remain in place to separate an unairconditioned warehouse space from conditioned occupied space.

1) Do we need to apply dampproofing or an air barrier product over one surface or the other?

2) What thickness of masonry do I need for a 2-hour fire rating or am I going to have to put in some shaftwall?
Brian E. Trimble, CDT
Senior Member
Username: brian_e_trimble_cdt

Post Number: 53
Registered: 08-2005
Posted on Friday, August 12, 2011 - 11:35 am:   Edit PostDelete PostPrint Post

Peter,

1) Why do you think you need to do this in the first place? In many cases this sounds like an OK idea, but you may want to run a moisture/condensation analysis to see if condensation could be a problem. From what I have heard WuFI does the kind of analysis you would need.

2) Fire rating of a tile wall depends on its thickness and the solidity of the unit. Most structural clay tile have a hard time getting to a 1 hour fire rating unless its a pretty thick unit or has plaster on one or both sides. A book called Tile Engineering by Plummer and Wanner is the book that lists the various fire ratings for the different tile units. It's out of print, but you may find it in different libraries. Also take a look at our Technical Notes 16 (www.gobrick.com). It has some information on hollow tile, but not much any more.

Besides the obvious shaft wall, you might be able to attain the rating with plaster/damproofing, or maybe another layer of masonry. This could take care of your fire rating and may give you improved sound resistance. Look at Technical Note 16 under the section on calculated fire resistance ratings.

Brian Trimble
Regional VP, Engr Services
Brick Industry Association
anon (Unregistered Guest)
Unregistered guest
Posted on Friday, August 12, 2011 - 11:51 am:   Edit PostDelete PostPrint Post

depends on the delta in RH between the two spaces. If hot/humid on unconditioned side, you more than likely need an air barrier (and also make sure the holes are plugged - receptacles, light switches, etc.) If there is enough of a delta in RH, then you will also need a vapor retarder... Dampproofing might work, but you'd have to look at the performance criteria (permeability).
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding

Post Number: 606
Registered: 11-2004


Posted on Friday, August 12, 2011 - 12:54 pm:   Edit PostDelete PostPrint Post

Peter-

I have a pdf of a document produced by (I think) HUD called "fire ratings of archaic materials" which I will email to you this weekend from home. It covers clay tile among many other materials and it wouldn't surprise me to see the clay tile portion of it based on the document Brian Trimble mentioned. It's a well researched document and I have used it with local AHJ several times as a basis for establishing fire ratings for in place construction. You might even be able to track it down online if you are familiar with the various government websites.
George A. Everding AIA CSI CCS CCCA
Ingersoll Rand Security Technologies
St. Louis, MO
John Bunzick, CCS, CCCA, LEED AP
Senior Member
Username: bunzick

Post Number: 1335
Registered: 03-2002
Posted on Tuesday, August 23, 2011 - 03:58 pm:   Edit PostDelete PostPrint Post

Peter,
I think that what you actually may want to use is an air barrier. In general, I think using one between any conditioned and non-conditioned space should be standard practice, for all of the same reasons that an air barrier is used on exterior wall.
Jim Sliff
Senior Member
Username: jim_sliff

Post Number: 89
Registered: 08-2010


Posted on Friday, August 26, 2011 - 12:02 pm:   Edit PostDelete PostPrint Post

George, if you happen to catch this note could you email me a copy as well? It could be helpful on some of the building conversion jobs going on in the Hollywood area.

Thanks!

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