30 CFR § 35.20 Autogenous-ignition temperature test.
(a)Purpose. The purpose of this test, referred to
hereinafter as the ignition-temperature test, is to determine the lowest
autogenous-ignition temperature of a hydraulic fluid at atmospheric pressure
when using the syringe-injection method.
(b)Description of apparatus--(1) test flask. The
test flask, which is heated and into which the test sample is injected, shall
be a commercial 200 ml. borosilicate glass Erlenmeyer flask.
(2)Thermocouples. Calibrated thermocouples
iron-constantan or chromelalumel and a potentiometer shall be used for all
temperature measurements.
(3)Syringe. A hypodermic syringe (0.25 or 1 cc.
capacity) equipped with a 2-inch No. 18 stainless steel needle and calibrated
in hundredths of a cubic centimeter (0.01 cc.) shall be used to inject
samples into the heated test flask.
(4)Timer. An electric timer or stopwatch
calibrated in not more than 0.2 second intervals shall be used to determine
the time lag before ignition.
NOTE: Time lag is the time that elapses between the instant of injection and
that of ignition of the test sample, as evidenced by flame.
(5)Furnace. The furnace in which the
ignition-temperature test is conducted shall consist of a refractory (alundum
or equivalent) cylinder 5 inches in internal diameter and 5 inches in height;
a transite-ring top and a transite-disk bottom, each of which is attached to
a metal cylinder. The furnace is heated by three elements as follows: (i) A
circumferential heater embedded in the refractory cylinder; (ii) a top or
toroidal-neck heater that surrounds the neck of the test flask; and (iii) a
flat base heater on which the test flask rests. The temperature of each
heating element shall be controlled independently by an autotransformer.
Means shall be provided for applying thermocouples at the neck, mid-section,
and base of the test flask, which shall be inserted upright in the
furnace.
(c)Test procedures--(1) Temperature control. Each
autotransformer shall be so adjusted that the temperature at the neck,
mid-section, and base of the test flask is uniform within ±2° F. of the
desired test temperature.
(2)Sample injection and timing. A 0.07 cc. test
sample shall be injected into the heated test flask with the hypodermic
syringe, and the syringe shall be withdrawn immediately. Measurement of time
shall start at the instant the sample is injected.
(3)Observations. (i) If flame does not result in
5 minutes or more after injection of the test sample, the sample shall be
considered nonflammable at the test temperature, and the timer shall be
stopped. The test flask shall then be flushed well with clean dry air and,
after a lapse of 15 minutes or more, the test shall be repeated with the test
flask temperature raised 50° F. ±2° F. above the first test temperature.
(c)(3)(ii) If ignition (flame) is observed in 5 minutes or less
after the injection of the test sample (0.07 cc.), the time lag (time
interval) shall be noted. After an ignition occurs the temperature of the
test flask shall be reduced 5° F., and the test procedure repeated in
decrements of 5° F. until ignition no longer occurs and this temperature
shall be noted as the first nonignition test temperature for the 0.07 cc.
sample.
(c)(3)(iii) The temperature shall be increased 50° F. ±2° F.
above the first nonignition test temperature, and the ignition-temperature
test procedure shall be repeated with a 0.10 cc. test sample injected into
the heated test flask.
(c)(3)(iv) If the lowest temperature at which ignition occurs
with the 0.10 cc. sample (in decrements of 5° F.) is lower than that obtained
with the 0.07 cc. sample, the ignition-temperature test procedure shall be
repeated using a test sample of 0.12 cc., then 0.15 cc., and so on by
increments of 0.03 cc. until the lowest ignition temperature is obtained.
(c)(3)(v) If the lowest temperature at which ignition is
obtained with the 0.10 cc. sample is greater than that obtained with the 0.07
cc. sample, the ignition temperature test procedure shall be repeated by
reducing the test sample to 0.05 cc. and then to 0.03 cc. until the lowest
ignition temperature is obtained.
(d)Appraisal of test. A fluid shall be considered
fire-resistant, according to the test requirements of this section:
Provided, That in no instance of the ignition-temperature test
procedure, as stated in this section, shall the ignition temperature of the
test sample be less than 600° F.
