Indeed, in North America, masonry sizes are 'nominal', and the actual sizes
allow for a 10 mm mortar joint. That is true whether the units are dimensioned
in metric or imperial.
John F-L
----- Original Message -----
From: Bill Hooper
To: U.S. Metric Association
Sent: Sunday, February 27, 2011 3:21 PM
Subject: [USMA:49935] Re: CMU supplier?
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
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SImplification Begins With SI.
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