Page 528 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

494 Applied Process Design for Chemical and Petrochemical Plants

Table 7-22
The Effect of Elevated Temperature on the Lower Flammable Limit of Combustible Solvents as Encountered in
Industrial Ovens]

Lower Flammable Limit
Percent Vapor by Volume
Flash Pt at Initial Temperature, °F
Closed
Solvent Cup Room 212 392 437 482 572 662
Acetone 3 2.67 2.40 2.00*
A.my! Acetate. lso 77 1.00 0.82 0.76*
Benzene -4 1.32 1.10 0.93 0.80*
Butyl Alcohol. Normal 100 1.56 1.27 1.22*
Cresot. Meta-Para 202 1.06t 0.93 0.88*
Cyclohexane -4 1.12 1.01 0.83*
Cyclohexanone 111 1.11 0.96 0.94 0.91 *
Ethyl Alcohol 54 3.48 3.01 2.64 2.47 2.29*
Ethyl Lactate. 131 1.55 1.29 1.22*
Gasoline -45 1.07 0.94 0.77*
Hexane. Normal -15 1.08 0.90 0.72*
High-Solvency Pet'roleum Naphtha 36 1.00 0.89 0.74 0.72 0.69*
Methyl Alcohol 52 6.70 5.80 4.81 4.62 4.44*
Methyl Ethyl Ketone 21 1.83 1.70 1.33*
Methyl Lactate 121 2.21 1.86 1.80 1.75*
Mineral Spirits, No. 10 104 0.77 0.63*
Toluene 48 1.17 0.99 0.82 0.72*
Turpentine 95 0.69 0.54*
v. M. & P. Naptha 28 0.92 0.76 0.67*
* Rapid end extensive thermal decomposition and oxidation reactions in vapor-air mixture at this temperature.
t Lower limit determined at 302°F.
t From NF?A Ouenertv, April 1950; UL Bulletin of Research No. 43.
*Rapid and extensive thermal decomposition and oxidation reactions in vapor-air mixture at this temperature.
tLower limit determined at 302°F
� From NFPA Quarterly, April 1950; UL Bulletin of Research No. 43.
Reprinted by permission, Fire Protection Handbook, 17th Ed. ( 1991) P: 4-32. National Fire Protection Association [34].

7-51 and 7-52A and B) or other means. Established refer-
ences include [ 44, 45, and 46]. % air== 100%-% ethane-% N2
Figures 7-51, 7-52A and Bare convenient diagrams for 48
studying the flammability of various compounds.
40
Where Autoignition Temperature (AlT) = the minimum tem- t
.,
perature at which a material begins to self-heat at a high enough �
� 32
rate to result in combustion. Reported in the Data Guide (Fig-
ure 7-51) as the temperature in air at one atmosphere. E
:::,
]
i.J' 24
z
-c
C,, = stoichiometric composition of combustionable vapor in :i:
air, expressed as a volume percent. l:;:j 16
T,, = equilibrium temperature at which C" exists over liquid
in dry air at a temperature, °C or °F per chart.
TL = equilibrium temperature at which the lower flammable 8
limit composition exists over liquid in dry air at one
atmosphere (theoretical flash point), °C or °F
T = equilibrium temperature at which the upper flammable 0 8 16 24 32 40 48 56
0
limit composition exists over liquid in dry air at one ADDED NITROGEN, volume-percent
atmosphere, °C or °F Figure 7-50. Effects of pressure on limits of flammability of ethane-
MP = melting point (freezing point), °C or °F nitrogen-air mixture at 26°C. By permission, U.S. Bureau of Mines,
BP = boiling point, °C or °F Bulletin 627 [43].