Masonry Magazine April 1975 Page. 14
Columns
Two methods of test are permitted. If the fireproofing is structural, the column specimen must be at least 9 ft (2.7 m) long and acceptance is based on ability to carry an axial load. If the fireproofing is not structural, the minimum column length is 8 ft (2.4 m) and acceptance is based on temperature rise in the structural column.
Hose Stream Test
For most ratings, ASTM E119 requires that walls undergo a fire and hose stream test as well as the fire endurance test. The test subjects a specimen to impact, erosion and thermal shock over the entire area of the surface which has been exposed to the fire. The specifications carefully denote nozzle size, distance, duration of application and water pressure at the base of the nozzle.
After the fire test, a wall specimen is pivoted outward and a hose stream of water played over the hot face.
Loading
During the fire endurance and the fire and hose stream tests, bearing walls are loaded to develop their full design stresses. Within 72 hr after the tests are completed, bearing walls must safely sustain superimposed loads twice those applied during the test.
Columns are loaded to develop the design stresses and then subjected to the standard fire on all sides. Where the fire protection is not designed to carry loads, an alternate method of test may be used in which the column is not loaded. Temperature rise, the sole criterion here, is measured by at least three thermocouples located at each of four levels.
CONDITIONS OF ACCEPTANCE (FIRE TESTS)
Non-Bearing Walls and Partitions
The test is successful and a fire resistance period may be assigned to the construction, if:
1. The wall or partition withstands the fire endurance test without passage of flame or gases hot enough to ignite cotton waste for a period equal to that for which classification is desired.
2. And, the wall or partition withstands the fire and hose stream test without passage of flame, of gases hot enough to ignite cotton waste, or of the hose stream.
3. And, the average temperature of nine thermocouples on the unexposed surface has not increased more than 250 F (121 C) above its initial temperature or 325 F (163 C) at any one point.
Bearing Walls
The conditions of acceptance for bearing walls are essentially the same as for non-bearing walls and partitions (above), with the following additions:
1. The specimen must also sustain the applied load during the fire endurance test.
2. And, after cooling, but within 72 hr of the test's completion, the wall must sustain twice the superimposed load applied during the test.
Columns
Columns with integral structural fire-proofing may be assigned a fire resistance period if they successfully sustain the superimposed load during the fire endurance test.
For fireproofing of columns not designed to carry loads, a fire resistance period may be assigned if the average temperature rise does not exceed 1000 F (538 C) and the maximum temperature rise does not exceed 1200 F (649 C) at any one point.
TERMINATION POINTS OF TEST METHOD
When an assembly under test reaches any one of the acceptance criteria; (1) ignition of cotton waste, (2) average temperature rise on unexposed side above 250 F (121 C) or 325 F (163 C) at any one point, or (3) fails to carry the design load if it is a loadbearing test; the test is terminated. The first two criteria relate to the function of providing a barrier against the spread of fire by penetration of the assembly, the third relating to structural integrity.
The termination point for fire tests of brick masonry walls is almost invariably due to temperature rise (heat transmission) of the unexposed surface. Brick masonry walls successfully withstand the load during test, the double load within 72 hr and the hose stream test conducted immediately after the wall has been subjected to the fire exposure. This structural integrity of brick masonry walls is attested to in many fires where the masonry walls have remained standing when all other parts of the building have been destroyed or consumed during the fire.