Polyurethane foam is an organic plastic polymer. Therefore, it is combustible and will burn in the presence of sufficient heat, ignition, etc. With the addition of flame retardants, PU foams can be formulated to pass flame-spread tests (i.e., ASTM E84), which measure their resistance to combustion when exposed to an open flame. However, polyurethane foam is not intended to be used by itself as a firestop material, according to current accepted U.S. model building codes, such as ICC, NFPA, etc., which specify that through-penetration firestop materials be tested according to ASTM E814 (UL 1479). In order to pass firestop testing as the sole material being tested (no composite structures), a material must essentially be noncombustible, which is not the case for polyurethane foams.
Several one-component foams have created confusion in the marketplace by being marketed with misleading and/or poorly worded claims. These products may create a serious liability risk to the end user if used improperly, as well as an even more serious potential for the unnecessary loss of life and property in the case of an accidental fire. Therefore, the purpose of this Technical Bulletin is to clarify and explain the test requirements for firestop materials. Note that this information is relevant for polyurethane foam in pressurized containers (i.e., aerosols) and is not applicable to "caulk-type" mechanically applied tubes of polyurethane, which may contain other inorganic additives that are not present in pressurized PU foam.
ASTM E814 (UL 1479) is a large-scale fire test that evaluates a complete “through-penetration” assembly for its ability to withstand exposure to flame, heat and a subsequent water hose stream (to simulate a real-world fire hose situation). Each tested firestop assembly will specify the type of floor or wall that is penetrated (e.g., concrete, steel, framing, etc.), as well as the penetrating item (e.g., metal conduit, plastic pipe, electrical tubing, etc.) and also the fill material (e.g., foam, mineral wool, E 136 fireblock, etc.). Each tested system is assigned an "F Rating" (an hourly rating indicating how long the assembly will withstand the passage of flame, along with a successful hose stream test), a "T Rating" (an hourly rating indicating how long the assembly will prevent a predetermined temperature rise on the back side of the assembly, along with a successful hose stream test), and sometimes an "L Rating" (air leakage) and a "W Rating" (water leakage). The hourly ratings apply only to the complete system. The individual components are not assigned ratings and are not intended to be interchanged between systems. Additionally, the substitution or elimination of components required in a system should not be made unless specifically permitted.
One-component foam (OCF) that has been tested to ASTM E814 (UL 1479) requires the additional use of an inorganic material, such as mineral wool, in order to achieve any of the above hourly ratings. Any use of these products in a through-penetration firestop must be done according to an approved system assembly and with the approval of the Authority Having Jurisdiction (AHJ)—in other words, the local building official.
In addition to the U.S. test methods described above, there is also a British Standard (BS 476) test protocol that is used primarily in Europe for evaluating through-penetrations. This test standard does not expose the fill material to the same open flame conditions, or hose stream test, and is therefore not equivalent to the U.S. test.
This information is provided as a service and is not necessarily meant to reflect any recommendation, guideline or position of Fomo Products, Inc. Each individual user must determine product suitability for any particular purpose.