New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1909-08-31
FIRE RESISTIVE TESTS.
Concrete Sho7cn To BE Best Among
Building Materials.
iron The Tribune Bureau.l

washington Aug so - Investigations recently
made by the United States Geological Survey 20
determine the fire resistve properties and rates OF
heat onducvity OF various building materials, and
the comparative efficiency OF the various methods
Of freproofng. showed that concrete withstood the
test better than any other material II was found
necessary. however TO use metal reinforcement In
concrete walls TO distribute the effect of the ex
pansion 1t is believed that these investigations
will lessen the liability OF loss by fire in
government buildings and greatly reduce their cost
through more efacient methods OF construction
The materials were subjected to the direct appli-
cation of heat for two hours. and were then i'm
mediately quenched with water Wherever possible
tests were made 70 determine the compressive
strength OF the materials after this treatment.
Temperatures observed at intervals and the
behavior of the materials during the test and the
condition OF their surfaces before and after the
heating and quenching noted
There thirty panels of various building
terfals tested in the furnace in the Underwriters
laboratories in Chicago under conditions unusually
severe. None Of the materials passed perfectly.
The temperatures used would hardly be reached In
ordinary wood fire A fact brought out most
clearly by these is the low heat transmission
rate Of Portland cement mortsrs and concretes.
This is OF the desirable qualities I'm materials
intended for freproofing purposes For marking the
cement blocks linen tags were fastened by wire
nails the interior walls NJ the time % moulding.
Most Of these tags remained in place during the
test and when the walls We're dismantled the tags
in every found entirely unchanged.
The apparatus in which these tests were made il
similar TO that generally used in determining the
fire resistive qualities OF IRE doors and windows.
II comprises a gas furnace with movable steel
frame fire brick wall door fourteen inches thick.
that shuts of the furnace from a radiation cham
Der. The distance between the permanent back
wall Of the furnace and the movable wall is thir-
teen and one-half inches. The movable wall II
hung from the lower hange OF beam by rollers.
and is easily moved out Of position by a weight at
tached 10 a wire cable. The wall has arehed
opening six feet wide and nine feet high The
material 20 tested is built up in this opening
a panel
The stationary back wall of the furnace contains
holes through which air is admitted control the
temperature. Back Of this wall piping and
valves for the control OF the air and gas supply.
The air pressure for the fame is maintained by
motor driven fan Gas enters the fire chamber at
the bottom through burners which are below the
level of the floor.
When a panel is ready for testing II is drawn
into position in front Of the main wall by a hand
winch and held there bp latch. The opening
around the edges is sealed by fire clay. Then the
sas is turned on and lighted by torch inserted
through a small door. The observer watch the
test through three small mica peephOes in. the
sides OF the furnace.
AT the end OF the heat treatment the latch is re-
leased and the weight at once draws the wall from
the furnace. In a regular test the material in the
panel is Immediately guenched with water from a
nozzle.