| Author |
Message |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 98
Registered: 11-2004
| | Posted on Thursday, January 12, 2006 - 12:07 pm: |    |
I’m just back from a seminar sponsored by Acme Brick on “Hollow Clay Masonry”. Here’s a brief summary:
In response to increasing natural gas and petroleum costs, the brick industry has begun to manufacture “Hollow Brick” (ASTM C-652) in lieu of the traditional “Face Brick” (ASTM C-216). The goal, of course, is reducing handling and shipping weight, while increasing surface area for more efficient heat distribution in the kiln. We will start to see more and more hollow brick being offered. Acme, for example, still makes modular brick under C-216, but has started making king size under C-652. Other manufacturers are changing similarly.
Acme believes that C-652 hollow brick will have the same external appearance and substantially the same performance as C-216 face brick. The bottom line, though, is that there will be less material and more void space; face shells and webs between voids will be thinner. For us specifiers, it will require changing the referenced standard, or keeping both standards. Performance criteria and physical standards between the two are the same, or similar; for example Grade SW and MW are the same, HBX = FBX; HBS = FBS, etc.
Anybody else run into this yet? Any significant concerns? |
Julie Root
Senior Member
Username: julie_root
Post Number: 33
Registered: 02-2004
| | Posted on Thursday, January 12, 2006 - 12:52 pm: | |
From my experience in CA it is very difficult to use hollow clay masonry in seismic zones.
In historic renovations in CA where it has to be kept for historic reasons it requires significant (i.e. costly) structural gymnastics to bring it up to code. Even with solid veneer and brick masonry in CA we have additional structural considerations.
In seismic zones I would recommend reviewing first with the local authorities. |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 99
Registered: 11-2004
| | Posted on Thursday, January 12, 2006 - 02:37 pm: | |
Point of clarification: they weren't talking structural clay tile (ASTMs C-34 and C-212), which it sounds like you might be, Julie.
This is essentially face brick, but with more void area. I would think that it might in fact be better for seismic -- less weight -- assuming all the other properties are equivalent, and assuming that the ties, anchors and reinforcing would be similar too. But I'm not a structural engineer.
They did mention that the hollow brick standard required greater shell and web thicknesses and higher minimum compressive strengths than the structural clay tile standard.
But, seismic is one of the things we have been kicking around here in the office today. Other issues:
Detailing (voids closer to face, impacts corbelling, etc.)
LEED and sustainable (less embodied energy)
Leaking (less "stuff" in the brick makes it easier for water to penetrate) |
David R. Combs, CSI, CCS, CCCA, MAI
Senior Member
Username: davidcombs
Post Number: 93
Registered: 08-2004
| | Posted on Thursday, January 12, 2006 - 04:58 pm: | |
George,
Re: :. . . shells and webs between voids will be thinner"
I would wonder -
Would this make the units more susceptible to cracking or breakage during shipping and construction, perhaps resulting in more waste? |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 168
Registered: 05-2004
| | Posted on Thursday, January 12, 2006 - 05:35 pm: | |
It may be helpful to note that "hollow brick" is defined by the standard as clay masonry having a certain percentage of the brick open (see ASTM C 652). Face brick with cores complying with ASTM C 216 must be at least 75% solid. I would imagine that there are significant variances in the amount of material in various types of hollow brick. |
John Bunzick, CCS, CCCA
Senior Member
Username: bunzick
Post Number: 454
Registered: 03-2002
| | Posted on Friday, January 13, 2006 - 09:10 am: | |
George, for corbelling and other detailing, don't the makers of hollow brick have solid units available for that purpose? |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 101
Registered: 11-2004
| | Posted on Friday, January 13, 2006 - 10:44 am: | |
Shipping concerns were mentioned in the seminar. That ties into the 75% solid (25% void) demarcation point between C-652 and C-216. In some cases, for example a modular brick, they may be taking a 24% void face brick and coverting to a 26% void hollow brick... no big deal and no significant difference in shipping (or really anything else). But with the bigger sized units and more face area on the bed face, and therefore proportionally thinner shells and webs, I suspect it becomes more of a problem.
As I understand it from the seminar, solid units for detailing, and also special shapes, will be available in hollow units to the same extent they are in face units. I mentioned corbelling, and similarly the end of a rowlock sill, because in residential and even light commercial construction, you'd never go the expense of special or solid units, as long as you detailed so that the cores didn't show. Now with the face shells thinner, some of those details that worked with cored face units probably won't work.
Thanks for the comments. Let me know if you start to hear about this from reps in your part of the country. |
Wayne Yancey
Senior Member
Username: wyancey
Post Number: 94
Registered: 05-2005
| | Posted on Friday, January 13, 2006 - 05:02 pm: | |
In Seattle, I have used hollow clay masonry only for fully grouted and reinforced cladding at Northwest Hopsital; enginnered and detailed by the structural engineer. The units were nominally 4 x 6 x 12 (3.5" x 5.5" x 11.5") with 1/2" mortar joints.
This cladding system requires structural steel for support (no loose lintels as may be found in brick veneer masonry). Some coordination is required to be sure the steel masonry supports are located in the proper Division 05 steel spec section.
The larger units also speed the laying up over the smaller units with frogs.
Wayne |
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