The FrazierTM McBurney Indentation Tester
The Frazier McBurney Indentation Tester is used for carrying out indentation tests on thermoplastic floor tiles, sometimes referred to as "asphalt" tiles, which are intended for use on rigid subfloors such as smooth concrete and suitably prepared wood floors. The tiles are fixed with an adhesive.
Frazier McBurney Indentation Tester
The apparatus consists essentially of an indenting rod with a hemispherical end 6.35mm diameter, through which loads of 0.907 kg and 13.6 kg can be applied to the test piece by rotating a handle. The indenting rod is fitted with a dial gauge for measuring the depth of penetration into the test piece.
A suitable flat rigid plate, at least 6.0mm thick, is required to support the test piece during the test.
The British Standard specification covers two tests, one at 25°C and one at 46°C. Both may be carried out on the same instrument.
The test piece is conditioned in air or water as laid down in the specification and is placed on a horizontal flat rigid plate with the Indentometer resting on the surface of the test piece.
The handle of the instrument is turned in a clockwise direction (looking on top) to lower the indentor and apply the initial load of 0.907 kg. The pointer of the dial gauge will start to rotate as the indentor is lowered. When the indentor first comes in contact with the test piece, the dial gauge pointer will temporarily stop rotating. This is the "null" point, at which the bezel of the dial gauge should be set to zero.
Continuing to turn the handle will lower the main 12.7 kg weight on to the indentor, thus applying the required total load of 13.6 kg to the test piece. Readings of the dial gauge are noted at 1 minute and 10 minutes after the application of the main weight for the 25°C test, or after 30 seconds in the case of the 46°C test.
Readings are taken at five scattered points on each test piece and the average of each set of five readings is recorded respectively as the 1 minute, 10 minute or 30 second indentations, as appropriate, of that particular test piece.
When carrying out the 46°C test in a water bath, care should be taken that a minimum of time elapses from the time the Indentometer is placed on the test piece and the application of the main weight. Some tiles are relatively soft at temperatures of about 46°C and false readings may be obtained unless this precaution is taken.