Abstract
In petroleum-fire fighting, destruction of air foam mainly caused by the radiant heat from the flame and the contact with the high temperature petroleum (abbreviated h. t. petrol. in the following).
Although the destruction due to radiant heat has been studied by many investigators, destruction due to h. t. petrol. has been scarcely studied and author has known that J. F. French’s paper3) had concerned only with that destruction in detail.
J. F. French and co-worker adopted the drained liquid volume as a measure to compare the resistance of air foam against h. t. petrol.
Author considered that the French’s method would not be suitable for that determination because the drainage was not proportional to the collapsed foam volume and there were foam compounds, whose foams drained rapidly but were destroyed a little by h. t. petrol.
A small scale test method for the resistance of foam to h. t. petrol. was given, which determined the collapsed foam volume directly and velocity of destruction of foam layer, that obtained from the former.
Experiments were conducted on three commercial foam compounds, in which two were keratine hydrolyzates and one unknown protein hydrolyzate, and on eight petroleums, in which five were petroleum products and three were crude oils.
The range of temperature of petroleums was 45～110°C.
From the experiments, the following results were obtained :
(1) Velocity of destruction of foam layer increased exponentially with the temperature of petroleums in range of the used experimental condition.
(2) Velocity of destruction was mainly governed by the contact with h. t. petrol. in the case of the used two keratine hydrolyzates and by the radiant heat of flame in the case of the unknown protein hydrolyzate.
From these facts, both the determinations of resistance to destruction of h. t. petrol. and of radiant heat could not be disregarded as the test for foam compounds.
(3) Considering fire risk and velocity of destruction, it would be suitable for the determination of resistance of foam to destruction of h. t. petrol., that the test method which presented by author in this paper, was conducted on gas oil at 70°C.
