Masonry Magazine April 1975 Page. 16
brick loadbearing walls. These walls were tested under working loads of 160 psi of gross area, except the 4-in. walls which were loaded to 80 psi. Ratings for 8-in. or thicker solid brick walls apply when units are laid in any of the mortars included in ASTM Specification C 270. Ratings for 4-in. solid walls apply when the units are laid with type M, S or N mortar.
Estimating Effects of Combustible Members. Where no fire tests are available for unplastered walls with combustible members framed in, the rating may be approximated from tests on similar walls without combustible framing by using the factors in Table 4.
TABLE 4
Estimating Factors for Unplastered Walls with Combustible Framing
| Wall Type
| All walls with 1 cell in wall thickness | 0.4 |
| Eight-inch walls with 3 cells in wall thickness | 0.4 |
| Eight-inch walls with 2 units in wall thickness | 0.4 |
| Eight-inch solid walls | 0.4 |
| All walls with 2 cells in wall thickness | 0.5 |
| All 12-in. walls except those with 1 or 2 cells in wall thickness | 0.67 |
Adapted from BMS32, Reference 7. For walls plastered with 19-in, 13 gypsum-sand plaster on the side opposite combustible framing, add 1 he to computed ratings over 3 hr and 1 hr to lesser ratings. No increase is permitted for plaster on the same side as combustible framing nor where combustible members enter from both sides. Multiply ratings of unplastered walls with no combustible framing by the appropriate factor to compute ratings for similar unplastered walls which support combustible framing. "Walls of units which are not cored more than 25 percent
Fire Resistance Ratings. Figures 4 through 7 list fire resistance ratings for various brick walls. Ratings listed are for loadbearing walls tested with working loads of 160 psi of gross area, except the 4-in. wall in Fig. 5 was loaded to 92 psi and the 4-in. wall in Fig. 4 was loaded to 80 psi.
Table 5 lists the fire resistance ratings for steel columns covered with brick.
TABLE 5
Fireproofed-Column Fire Ratings
| Construction |
|---|---|
FIG. 4 One-Hour Fire Rating
Construction shown is loadbearing.
REFERENCES
1. Fire Resistance Ratings, December 1964; American Insurance Association, 85 John Street, New York, NY 10038.
2. Harry D. Foster, A Study of the Fire Resistance of Building Materials, Engineering Experiment Station Bulletin No. 104, January 1940; Ohio State University, Columbus, Ohio.
3. Standard Methods of Fire Tests of Building Construction and Materials, ASTM Designation E 119; American Society for Testing and Materials, 1916 Race St., Philadelphia, PA 19103.
4. Fire Resistance of Brick Walls, Technical News Bulletin No. 124, August 1927; National Bureau of Standards, Washington, D.C.
5. Ingberg, Griffin, Robinson, Wilson; Fire Tests of Building Columns, Technologic Paper No. 184, 1921; National Bureau of Standards, Washington, D.C.
6. Fire Endurance of Hollow Brick Walls, Technical News Bulletin, Vol. 35. No. 4, April 1951; National Bureau of Standards, Washington, D.C.
The following three references are Building Materials and Structures Reports, published by the National Bureau of Standards, Washington, D.C.:
7. Fire-Resistance Classifications of Building Constructions, BMS92, October 7, 1942.
8. Fire Tests of Brick Walls, BMS143, November 30, 1954.
9. Combustible Contents in Buildings, BMS149, July 25, 1957.
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