ASTM E1292-94

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: E 1292 – 94
Standard Specification for
Gravity Convection and Forced Ventilation Incubators
This standard is issued under the fixed designation E 1292; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope particular type of incubator when measured in accordance with
the procedure given in Section 5.
1.1 This specification covers the performance requirements
3.3 The recovery time of the incubating chamber shall
for general purpose air incubators ordinarily used for incubat-
conform to the requirements specified in Table 1 for the
ing procedures, which have an incubating chamber up to 0.6
3 3
particular type of incubator, when tested in accordance with the
m (25 ft ) in volume. It is applicable to gravity and forced
procedure specified in Section 6.
ventilation incubators designed to operate over all or part of the
temperature range from 5°C above ambient to 75°C.
4. Test Methods
1.2 This specification does not include any requirements for
4.1 Temperature Uniformity:
the safe handling of harmful or disease bearing organisms.
4.1.1 Place nine calibrated thermocouples (Note 1) made
1.3 The following precautionary caveat pertains only to the
from iron-constantan or copper-constantan wires approxi-
test method portions, Sections 4, 5, and 6, of this specification.
mately 0.5 mm in diameter (No. 24 gage) and having a junction
This standard does not purport to address all of the safety
size of not more than 2 mm (0.08 in.) in the empty incubating
concerns, if any, associated with its use. It is the responsibility
chamber with shelves in place, and vents open. Locate one
of the user of this standard to establish appropriate safety and
thermocouple in each of the eight corners of the incubator
health practices and determine the applicability of regulatory
approximately 5 cm (2 in.) from each wall, and place the ninth
limitations prior to use.
thermocouple within 2.5 cm (1 in.) of the geometric center of
2. Types the chamber. A minimum length of 30 cm (12 in.) of wire for
each thermocouple shall be inside the incubator to minimize
2.1 This specification covers the following four types of air
the conduction of heat from the thermocouple.
incubators:
2.1.1 Type 1A—An incubator ventilated by gravity convec-
NOTE 1—If calibrated thermocouples are not available, nine thermo-
tion having a uniformity of temperature within 3 % of the
couples made from the same spool of wire may be used, provided they
give the same value for temperature when placed adjacent to one another
differential between incubator and ambient temperature,
in the incubating chamber at the temperature of the test.
2.1.2 Type 1B—An incubator ventilated by gravity convec-
tion having a uniformity of temperature within 6 % of the
4.1.2 Bring the incubator to the specified temperature and
differential between incubator and ambient temperature,
allow it to reach a steady state (Note 2). Record the tempera-
2.1.3 Type 2A—An incubator ventilated by forced ventila-
ture of the nine thermocouples for a period of at least 12 h and
tion having a uniformity of temperature within 2 % of the
determine from the record the maximum deviation of each
differential between incubator and ambient temperature,
point from the desired temperature. The ambient room tem-
2.1.4 Type 2B—An incubator ventilated by forced ventila-
perature shall vary by not more than a total of 5°C and the line
tion having a uniformity of temperature within 5 % of the
voltage shall not vary by more than a total of 5 % during the
differential between incubator and ambient temperature.
test.
NOTE 2—Some incubators may require as much as 12 h to reach a
3. Performance Requirements
steady state. If a steady state does not exist, there is a drift in the
3.1 The temperature within the incubating chamber shall be
temperature toward the steady state condition.
controlled by an automatic device, and shall be uniform within
the tolerances given in Table 1, when tested in accordance with 5. Rate of Ventilation
Section 4.
5.1 Seal the ventilation ports, doors, and all apertures of the
3.2 The rate of ventilation of the incubating chamber shall
incubator with adhesive tape, or by other means to prevent any
conform to the requirements specified in Table
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