- Author
- Underwriters Laboratories, Incorporated
- Title
- Study of Smoke Ratings Developed in Standard Fire Tests in Relation to Visual Observations.
- Coporate
- Underwriters Laboratories, Inc., Northbrook, IL
- Report
- Bulletin of Research 56, April 1965, 59 p.
- Keywords
- smoke | fire tests | equipment design | test methods | building materials | smoke measurement | smoke density | UL 723 | visibility
- Identifiers
- smoke accumulation room; time relationships for individual materials; average smoke density/time relationships; effects of changes in tunnel furnace air velocity on smoke density/time relationships
- Abstract
- This investigation was directed toward establishing the relationship between smoke ratings of various building materials as developed by Underwriters' Laboratories, Inc. Steiner Tunnel Test Method for Fire Hazard Classification of Building Materials, Standard UL 723 (ASTM E 84) O\IFPA-255) (ASA A2,5-1963) and the loss of visibility in a room in which the smoke from the rating tests was collected. The smoke data presented has not been related to other important fire hazard characteristics of the materials tested. Such other factors include spread of flame, contribution of fuel, combustibility, and toxicity as well as adverse physiological effects on the human body resuhlng from exposure to heat and the effects of inhaling hot gases. The results of the investigation are influenced by and pertain to the fixed experimental parameters such as the size of specimen and exposure fire used in the standard test method, the volume of the room into which the' smoke was vented, the method of introducing the smoke into the room, and the location of the lighted exit signs and instrumentation as well as the nature of the material tested. Within these limitations, a visual concept of a numerical indication of smoke production was determined. Under the test conditions, visual observations and photographs of lighted exit signs in the test room were related to a scale of smoke density. With this procedure, it was established that a 0 scale reading was recorded with no reduction in visibility and 5 for total obscuration. Good visibility existed witha scale reading of 3, despitethe presence of some smoke in the room, fair visibility at 4, and marginal or poor at 4.8. Materials tested included red oak flooring, 1/4 and 3/8 inch plywood, 3/4 inch treated plywood, 1/4 inch tempered hardboard, 1/2 inch cellulosic tile, poly (vinyl-chloride) flat and corrugated panels, polyester reinforced corrugated panels, 1/32 and 1/16 inch plastic laminates adhered to steel, gypsum boardand asbestos cement board, 1/16 inch plastic laminates not bonded, polyethylene film mechanically secured to mineral fiberboard, vinyl wall coverings adhered to asbestos cement board, paint coatings on 3/8 inch plywood, 5/8 inch mineral fiberboard, and 1 inch glass fiberboard. A summary of the data showed that all tested materials having a Smoke Developed rating of 16 or less produced a visibility scale reading in the smoke accumulation room of not more than 0.8 in six minutes. Materials having a Smoke Developed rating of 200 or less produced a visibility scale reading of not in excess of 3 in six minutes. Materials having Smoke Developed ratings of 200-325 showed "good" to "margina1" visibility in all cases in six minutes. Materials having Smoke Developed ratings above 325 showed "good" to "marginal" visibility (scale readings of 3 to 4.8) in a few cases; other materials produced conditions of "marginal" visibility to obscuration in the six minute period. All of these data relate to the room size and other conditions of test. Although general correlation existed between the Smoke Developed rating of a material and the loss of visibility incurred in the smoke accumulation room, variations occurred and were largely credited to the fact that the Fire Hazard Classification method of smoke rating is representative of the total smoke developed in a ten minute interval, without respect to when the smoke is produced, whereas the density readings in the smoke accumulation room are senitive to the time element. Increasing or decreasing air velocity over certain samples of material burned in the tunnel furnace, by a factor of approximately 30%, showed that Smoke Developed ratings decreased as velocities increased. With red oak flooring and 3/8 inch untreated walnut faced plywood, Smoke Developed ratings varied from 1/3 normal at high velocity to 2-1/2 to 3 times normal at low velocity. With poly (vinyl-chloride), ratings varied from about 2/3 normal at high velocity to 1-1/3 normal at low velocity.