ASTM_E_1292_-_94_2011.pdf

Designation:E129294(Reapproved 2011)Standard Specification forGravity Convection and Forced Ventilation Incubators1This standard is issued under the fixed designation E1292;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification covers the performance requirementsfor general purpose air incubators ordinarily used for incubat-ing procedures,which have an incubating chamber up to 0.6m3(25 ft3)in volume.It is applicable to gravity and forcedventilation incubators designed to operate over all or part of thetemperature range from 5C above ambient to 75C.1.2 This specification does not include any requirements forthe safe handling of harmful or disease bearing organisms.1.3 The following precautionary caveat pertains only to thetest method portions,Sections 4,5,and 6,of this specification.This standard does not purport to address all of the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Types2.1 This specification covers the following four types of airincubators:2.1.1 Type 1AAn incubator ventilated by gravity convec-tion having a uniformity of temperature within 3%of thedifferential between incubator and ambient temperature,2.1.2 Type 1BAn incubator ventilated by gravity convec-tion having a uniformity of temperature within 6%of thedifferential between incubator and ambient temperature,2.1.3 Type 2AAn incubator ventilated by forced ventila-tion having a uniformity of temperature within 2%of thedifferential between incubator and ambient temperature,2.1.4 Type 2BAn incubator ventilated by forced ventila-tion having a uniformity of temperature within 5%of thedifferential between incubator and ambient temperature.3.Performance Requirements3.1 The temperature within the incubating chamber shall becontrolled by an automatic device,and shall be uniform withinthe tolerances given in Table 1,when tested in accordance withSection 4.3.2 The rate of ventilation of the incubating chamber shallconform to the requirements specified in Table 1 for theparticular type of incubator when measured in accordance withthe procedure given in Section 5.3.3 The recovery time of the incubating chamber shallconform to the requirements specified in Table 1 for theparticular type of incubator,when tested in accordance with theprocedure specified in Section 6.4.Test Methods4.1 Temperature Uniformity:4.1.1 Place nine calibrated thermocouples(Note 1)madefrom iron-constantan or copper-constantan wires approxi-mately 0.5 mm in diameter(No.24 gauge)and having ajunction size of not more than 2 mm(0.08 in.)in the emptyincubating chamber with shelves in place,and vents open.Locate one thermocouple in each of the eight corners of theincubator approximately 5 cm(2 in.)from each wall,and placethe ninth thermocouple within 2.5 cm(1 in.)of the geometriccenter of the chamber.A minimum length of 30 cm(12 in.)ofwire for each thermocouple shall be inside the incubator tominimize the conduction of heat from the thermocouple.NOTE1If calibrated thermocouples are not available,nine thermo-couples made from the same spool of wire may be used,provided theygive the same value for temperature when placed adjacent to one anotherin the incubating chamber at the temperature of the test.4.1.2 Bring the incubator to the specified temperature andallow it to reach a steady state(Note 2).Record the tempera-ture of the nine thermocouples for a period of at least 12 h anddetermine from the record the maximum deviation of eachpoint from the desired temperature.The ambient room tem-perature shall vary by not more than a total of 5C and the linevoltage shall not vary by more than a total of 5%during thetest.NOTE2Some incubators may require as much as 12 h to reach asteady state.If a steady state does not exist,there is a drift in thetemperature toward the steady state condition.5.Rate of Ventilation5.1 Seal the ventilation ports,doors,and all apertures of theincubator with adhesive tape,or by other means to prevent anyair from passing through the incubator(Note 3).Connect a Whmeter with the smallest division reading in 0.01 Wh in theelectrical supply line to the incubator.1This specification is under the jurisdiction of ASTM Committee E41 onLaboratory Apparatus and is the direct responsibility of Subcommittee E41.06 onWeighing Devices.Current edition approved Dec.1,2011.Published December 2011.Originallyapproved in 1989.Last previous edition approved in 2006 as E1292 94(2006).DOI:10.1520/E1292-94R11.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE3In forced circulation incubators,th