How Many Tests of SFRM Are Needed?

Donald E. Smith

February 2005

We are having a dispute with the owner of a building we are constructing. Our interpretation of AWCI’s Technical Manual 12A, Third Edition Standard Practice for the Testing and Inspection of Field Applied Sprayed Fire-Resistive Materials is that we are only required to take one test of spray-applied fireproofing for each 10,000 square feet of floor area. The owner says we have to take three tests for each 10,000 square feet of floor area—one test for each column, beam and floor slab. Who is correct?

After talking with several colleagues we have come to the determination that one test for each element—slab, column andbeam—is required for each 10,000 square feet. Specifically, in AWCI’s technical manual, in paragraph 5.4.2, the second sentence states: "Density shall be determined by conducting tests on specimens from each of the following elements: a flat portion of the deck; a beam; either the bottom of the beam lower flange or the beam web; and a column, either column web or the outside of the column flanges.” ASTM E 605-93 was used in developing 12A. E 605 states the following in 8.2.1: "Conduct one density test at random on each of the following elements, per floor or every 930 m2 (10,000 ft2), whichever provides the greatest number of tests, the flat portion of the deck; a beam, either the bottom of the beam lower flange or the beam web; and a column, either the column web or the outside of one of the column flanges.”

Based on these two standards, three tests in 10,000 square feet would be required.

Hopefully you can resolve an argument we are having. When describing our product and its inherent capabilities, we need clarification on the correct terminology to use regarding the testing results of ASTM E84. Is this Class I, II, III, or is it Class A, B, C? In the industry today, which of these is the designation that most architects seek?

So you can better understand the answer, here is a little bit of background.

E84-04 Standard Test Method for Surface Burning Characteristics of Building Materials is a test that determines the relative burning behavior of the material by observing the flame spread along the specimen. Flame spread and smoke developed index are reported. However, there is not necessarily a relationship between these two measurements. It is common to see the flame spread and smoke developed results listed in the description of a product’s characteristics.

Class designation A, B and C come from National Fire Protection Association and are described in NFPA 101 Life Safety Code. The classes are related to the flame spread and smoke developed results from ASTM

E84. The classification system is described in NFPA 101 as follows:
  • Class A, 0–25 Flame Spread Index: 0–450 Smoke Developed Index.
  • Class B, 26–75 Flame Spread Index: 0–450 Smoke Developed Index.
  • Class C, 76–200 Flame Spread Index: 0–450 Smoke Developed Index.
Class designation of I, II and III correspond to A, B and C, respectively, and come from the model building codes. These designations do not preclude a material being otherwise classified by the authority having jurisdiction.
The application of a given designation may have to be adjusted to suit the requirements of the local authority having jurisdiction.

About the Author
Donald E. Smith, CCS, is AWCI’s director of technical services.
Send your questions to smith@awci.org