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236 F I R E R E S E A R C H Kordina, K . and Meyer-Ottens, C . ( Inst i tut fu r BaustofiOcunds und Stahlbetonbau der Technichen Universitat, Braunschweig, Federal Republic of Germany) "Relation between Fire Load and Temperature at Tests of Concrete and Wooden Partitions according to D I N 4102" (in German), Materudpruf 11(8), 1 (1971) Sections: A, G Subjects: Concrete; Wood; Partitions, Fire resistance. Test methods; Fire load; Fire temperature; D I N 4102; Walls, Furnace tests, ISO-R 1060, Buildmg fires Authors' Summary Two wooden partitions, as well as one reinforced concrete and one aerated concrete wall, were tested at fire loads which caused furnace temperatures following the standard time-temperature curve ( " E T K " ) according to D I N 4102 (ISO-R 1060) Two other wooden partitions were tested each wi th a fire load of "100 q = 100% q = q (reinforced concrete)" which was necessary to produce the standard time-temperature curve for the reinforced concrete wall The corresponding furnace temperatures were measured The tests have shown that the fire load f rom the furnace accordmg to the standard time-temperature curve " E T K " is 58 q only wi th wooden partitions, whereas 100 q represent the corresponding fire load f rom the furnace for reinforced concrete walls, the furnace temperatures determined at comparable wooden partitions are a fire load from the furnace of 100 q=q (remforced concrete) at any time exceed by about 28% the value required by " E T K " standard time-temperature curve; the wooden partitions tested according to the standard time-temperature curve " E T K " burnt down 100% more slowly than comparable walls under a fire load f rom the furnace 100 g = g (remforced concrete), l e , their resistance to fire was half the time higher than wi th comparable wooden partitions. Combustible structures thus have remarkable influence on the development of fire and should not be neglected Due to these test results the question may arise whether this hitherto applied test procedure for strjictures according to D I N 4102(2) is correct The test results wi l l likely form a new basis for a rework of the standards of D I N 4102 (Behaviour of Building Materials and Structures in Fire) as well as of D I N 18 230 (Reqmrements for Structural Fire Protection of Industrial Buildings) Law, M . (Joint Fire Research Organization, Boreham Wood, England) "Safe Distances f rom Wired-Glass Screemng a Fire," The Institution of Fire Protection Quarterly 29 (73), 62 (1969) Section: A Subjects: Safe distances, Wired glass; Glass panels Reviewed by J. Malcolm
ABSTRACTS AND R E V I E W S 237 I n this paper the author addresses two problems. The first concerns the deter- mination of the mimmum distance f rom wire-reinforced glass panels forming fire barriers, at which combustibles such as wood and paper may prudently be stored. The second concerns the minimum distance durmg escape f rom fire at which personnel may approach wire-reinforced glass panels affording protection f rom open flame I n both of these problems, the minimum distances are considered in terms of the area of exposure and fire intensity. I n the second problem, the speed wi th which personnel can escape is also considered The stated purpose of the discussion is to give guidance in such general terms that each situation may be examined m light of its individual ment Reference is made to the existing U . K . building regulations and codes* and previously developed data on building fire performance characteristics such as fire radiation intensities anticipated f rom specified fire loadings. The fire per- formance characteristics accepted as basis for this discussion are as follows. a. To preclude the ignition of combustibles such as wood and paper, by exposure to thermal radiation,* the radiation intensity must not exceed 0 8 calories cm"^ sec-'. b. A 6 mm thick wire-reinforced glass pane at equilibrium temperature wi th fire on one side transmits about 50 percent of the incident thermal radiation. d. Fire loads of 45 and 170 kgm-« area give fire seventies equivalent to "one- half hour" and "one hour" fire resistance, respectively, and maximum thermal radiation intensities of 0 9 and 3 7 calories cnr^ sec"', respectively.* e. For design, the U . K . Building Regulations' treat a thermal radiation value of 2 0 calories cm- ' sec-' as a "normal intensity" fire Since the presence of a wired-glass screen would reduce transmitted radiation f rom a "one-half hour" fire or a "low intensity" fire to a value less than or very close to the critical radiation intensity for igmtion (0 8 calones cm-* sec-'), the author dismisses the problems of shielding combustible storage areas at these fire intensities. The "one hour" and "normal intensity" fires are considered as essentially identi- cal, that is w i th a radiation mtensity of 4.0 calones cm-* sec-'. The radiation intensity transmitted by a wire-reinforced glass screen is taken as 2 0 calones cm"* sec"'. The "space configuration factor" for the 4 0 calones cm"* sec"' intensity IS then determined as the factor apphed reducing the radiation intensity to the critical value of 0 8 calories cm-* sec"', below which igmtion by thermal radiation would not occur, i e , 0.8/2 0 yields 0 4, the critical space configuration factor The parameters selected for correlation wi th the space configuration factor are iS, distance f rom screen to the combustible being shielded by the screen D, height of the wired-glass screen L , length of the wired-glass screen N=L/D (length of screen/height of screen) Using these parameters, Fig 1 shows the parametnc relationships corresponding to a space configuration factor of 0 4 for three different positions of the combustible surface wi th respect to the screen
238 F I R E R E S E A R C H The diagram of Fig 2 shows minimum spacing of combustibles f rom a screen of length N D which shields the combustible f rom fire Criteria for safe egress of personnel, while being shielded f rom direct fire radia- tion by wire-reinforced screens, require consideration of additional data concerning the levels of thermal radiation tolerated by human subjects as a function of exposure duration "'^ Maximum levels based on tolerance to pair are given below. Thermal radiation Time Maximum path (meters) traversed at intensity tolerated speed ti t;=0 2m sec"' 0 5m sec"' 2 Om sec"' Calories cm~' sec"' sec i; = 40 ft/nun 100 ft/min 400 ft/min 0 23 5 1 2 5 10 0 14 10 2 5 20 0 09 20 4 10 40 0 07 30 G 15 60 0 06 40 S 20 80 The author rationalizes that escape from a fire wi l l most likely be effected during early stages of combustion before the maximum radiation intensity is developed Hence, for the purpose of the discussion the author selects a value for the probable radiation intensity during escape equal to one-half the maximum intensity for the fire category Smce the wired-glass screen transmits only 50 percent of the mcident radiation, the resultant mtensities of transmitted radiation for the probable radia- tion exposure during escape for the "low mtensity" and "normal intensity" fires are then 0.5 and 1 0 cal cm"* sec"', respectively For the above radiation intensities and at selected walking speeds, Figures 3 and 4 show the required safe distances f rom wired-glass screens installed along the escape route at either one or two meters f rom the floor level The dotted line on these figures shows distances f rom the British Standard Code of Practice' for glazing The author concludes that combustible materials located behind glazed panels should normally be located a distance approximately equal to the panel heights and that escape routes used by more than one or two people should not normally have glazing at heights less than 1 m above floor level Eight-references are cited, and an appendix showing two examples of "safe distances" calculations using the figures is presented. References 1 "Glazing and Fixing of Glass for Buildings," British Standard Code of Practice CP 152 (1966) 2 L A W , MARGA R ET "Heat Radiation from Fires and Building Separation," Fire Research Tech- nical Paper No B London, H M Stationery Office (1963) 3 "Buildmg Regulations 1965," Hmise of Commons S I No 1373 London, H M Stationery Office (1965) 4 "Building Standards (Scotland) Regulations 1963," House of Commons S I 1963, No 1897 London, H M Stationery Office (1963) 5 BUTCHER, E G AND L A W , MARGARET "Comparison between Furnace Tests and Experi- mental Fires," Joinl Fire Research Organization Symposmm No S, Behavior of Structural Steel m Fire London, H M Stationery Office (1968)
