Exactly right. You will find that brick and block sold in the U.S. in
sizes measured in inches are likewise "undersized" in actuality from
their nominal size. The mortar joint allowance is the reason.
Jim
On 2011-02-27 1016, John M. Steele wrote:
I believe the nominal is the "modular size" and the actual dimensions
allow for a 10 mm (or 3/8") mortar joint. That makes sense to me on
length and width, not so clear on thickness, but I guess it allows any
orientation, corners, etc.
--- On *Sun, 2/27/11, Bill Hooper /<[email protected]>/* wrote:
From: Bill Hooper <[email protected]>
Subject: [USMA:49935] Re: CMU supplier?
To: "U.S. Metric Association" <[email protected]>
Date: Sunday, February 27, 2011, 10:21 AM
On Feb 24 , at 10:06 AM, Pierre Abbat wrote:
... (about)
concrete masonry units, ... suppliers of CMU. I found ... this one:
http://www.fostersoutheastern.com/shapes.htm?section=10
I checked this web site.
Curiously, the list of metric blocks shows dimensions that are
different from the "named size" of the blocks.
For example, the block that is called SP1S1E is labeled "200 x 100 x
400" (with no units). However, the actual dimensions on the drawing
of the block are 190 mm by 90 mm by 390 mm. Why is that?
Is it some sort of soft conversion from a standard inch size? Or is
it the "2 by 4" problem (as in lumber) where the common designation
(2 x 4) does not mean "2 inches by 4 inches" with the actual size
being smaller than 2 inches by 4 inches.
Is this a problem with the metric usage or is this just a common,
strange way that all building products are labeled and sold?
Bill Hooper
1800 mm tall
Fernandina Beach, Florida, USA
==========================
SImplification Begins With SI.
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632 Stony Point Mountain Road
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