Evening star., 1933-06-10
FLOOR MATERIALS
TESTED FOR WEAR
Marbles, Granite and Lime
stone Survey Conducted by
Bureau of Standards.

With specially designed testing ma
chine, the Bureau of Standards ha.
conducted a study of several marbles
limestones, etc, that are used for deco
rative floors, in an effort to satisfy 8
demand for data on the wearing quail
ties of hoor-surfacing materials.
The action of the testing machine
was compared with the actual wear or
such materials under service conditions
During the past four years. re-
port on the subject, issued by the
Bureau of Standards, says, "a con-
siderable number of materials have been
tested for Federal buildings, and data
have been obtained on a variety OF
materials. Since there are frequent
calls for such information the results
have been assembled in a paper for
publication. This contains results on 79
marbles. 80 limestones, % sandstones, 80
states, II GRANTEES, IL serpentines, 10
travertines, and a few miscellaneous
materials that do not fall under the
above claSsifications.
Considerable Range Shown.
1.-THE means employed for expressing
the results give a simple way of COM
pairing different materials, the numeri-
cal values being proportional to abra-
sive resistance.
The marbles show a considerable
range in wear values. The highest re-
suit obtained was ALI for fine-grained
black marble. while the lowest, ST,
was recorded for rather loose-grained
white marble The average of the 79
marbles was 1873, which is approximate
1y equal to the values obtained for those
marbles that are largely used for floor
tile.
THE average for 80 limestones was
found to be 84. This group contained
q few materials that would probably
not be used in floors except in positions
where the traffic is very light. The
highest values for any limestones tested
was 24.1.
twenty-five sandstones gave an aver
age of 1873 and a range from 1.6 to
264. The abrasive resistance of this
type of material seems to depend large
1y on the cohesive strength, since the
wear results mainly in loosening and
removing quartz grains from the sur
face exposed to abrasion. The highest
value obtained for slate was lit, while
the average was TT. The small range
in abrasive resistance of this class OF
material indicates that there is little
advantage of one slate over another Tor
flooring purposes.
>Granites Have High Values.
although the GRANTEES are seldom
used for floor -surfacing materials they
are often used in the approach steps
Of buildings. The 10 GRANTEES tested
showed uniformly high values with an
average of SO.
''The serpentines find frequent use
in floors as decorative strips or inlays.
The average of II serpent1nes was found
to be nearly as high as that OF GRANTEES,
but a large range of values was evi-
dent
"The average of 10 travertines was
found to be 1877. The travertineS used
to a considerable extent in floors and
steps gave values somewhat below the
average for marble.
THE wear values of the different
stone now available should prove OF
special interest to architects IN cases
where several varieties of tile are COM
bined for color scheme. Past experience
has shown that selection based on color
alone may lead to undesirable results"