IPC-TM-650 EN 2022 试验方法.pdf - 第650页
5.1.6 The stock cultures may be kept for not more than four months at 6 ± 4°C [42.8 ± 7.2°F] at which time subcultures shall be made and new stocks shall be selected from the subcultures. 5.1.7 If genetic or physiologica…
1.0
Scope
The
fungus resistance test is used to determine
the resistance of materials to fungi and to determine if such
material is adversely affected by fungi under conditions favor-
able for their development, namely high humidity, warm atmo-
sphere, and presence of inorganic salts.
2.0
Applicable Documents
None
3.0
Test Specimen
Standard
laboratory glass slides of 50
mm x 50 mm [2.0 in x 2.0 in] minimum size.
4.0
Apparatus and Reagents
4.1 Test Chamber
The
autoclave shall be capable of main-
taining 30 ± 1°C [86 ± 1.8°F] and 95 ± 2% relative humidity
and an ultra violet (360 nm) source for subsequent decontami-
nation. Provisions shall be made to prevent condensation
from dripping on the test item. There shall be free circulation
of air around the test item and the contact area of fixtures
supporting the test item shall be kept to a minimum.
4.2
Sterilizer
4.3
Centrifuge
4.4
pH
Meter
4.5
Colony
Counter
4.6
Incubator
4.7
Dishwasher
4.8 Petri
Dishes
4.9
Filter
Paper
4.10
Media
Solutions
4.11
Micro-organisms
4.12
Atomizer,
15,000 ± 3000 spores
5.0
Procedures
5.1 Preparation of Test Media
5.1.1 Mineral-Salts Solution
Prepare
the solution to contain the following:
Potassium dihydrogen orthophosphate(KH
2
PO
4
)
........... 0.7g
Potassium monohydrogen orthophosphate (K
2
HPO
4
)
... 0.7g
Magnesium sulfate heptahydrate (Mg SO
4
•7H
2
O)
......... 0.7g
Ammonium Nitrate ((NH
4
NO
3
)
........................................ 1.0g
Sodium chloride (NaCl) .............................................. 0.005g
Ferrous sulfate heptahydrate (FeSo
4
•7H
2
O)
.............. 0.002g
Zinc sulfate heptahydrate (ZnSO
4
•7H
2
O)
................... 0.002g
Manganous sulfate monohydrate (MnSO
4
•H
2
O)
........ 0.001g
Distilled water ........................................................... 1000 ml
Sterilize the mineral salts solution by autoclaving at 121°C
[249.8°F] for 20 minutes. Adjust the pH of the solution by the
addition of 0.01 normal solution of NaOH so that after steril-
ization the pH is between 6.0 and 6.5. Prepare sufficient salts
solution for the required tests.
5.1.2
Purity of Reagents
Reagent
grade chemicals shall
be used in all tests. Unless otherwise specified, it is intended
that all reagents shall conform to the specification of the Com-
mittee on Analytical Reagents of the American Chemical Soci-
ety, where such specifications are available.
5.1.3
Purity of Water
Unless
otherwise specified, refer-
ences to water shall be understood to mean distilled water or
water of equal purity.
5.1.4
Preparation of Mixed Spore Suspension
The
following test fungi shall be used:
Description .................................................................. ATCC
Aspergillus niger ............................................................ 9642
Chaetomium globosum ................................................. 6205
Gliocladium virans ......................................................... 9645
Aureobasidium pullulans ............................................... 9348
Penicillium funiculosum ................................................. 9644
5.1.5
Maintain
cultures of these fungi separately on an
appropriate medium such as potato dextrose agar. However,
the culture of chaetomium globosum shall be cultured on
strips of filter paper on the surface of mineral salts agar. (Min-
eral salts agar is identical to mineral salts solution, but con-
tains in addition 15.0 g of agar per liter.)
2215
Sanders Road
Northbrook, IL 60062-6135
IPC-TM-650
TEST
METHODS MANUAL
Number
2.6.1.1
Subject
Fungus
Resistance – Conformal Coating
Date
07/00
Revision
Originating Task Group
Conformal Coating Task Group, 5-33a
Material
in this Test Methods Manual was voluntarily established by Technical Committees of IPC. This material is advisory only
and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this
material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.
Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.
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5.1.6
The
stock cultures may be kept for not more than four
months at 6 ± 4°C [42.8 ± 7.2°F] at which time subcultures
shall be made and new stocks shall be selected from the
subcultures.
5.1.7
If
genetic or physiological changes occur, obtain new
cultures as specified above. Subcultures used for preparing
new stock cultures or the spore suspension shall be incu-
bated at 30 ± 1°C [86 ± 1.8°F] for nine to 12 days or longer.
5.1.8
Prepare
a spore suspension of each of the five fungi
by pouring into one subculture of each fungus, a 10-ml por-
tion of a sterile solution containing 0.05 g per liter of a non-
toxic wetting agent such as sodium dioctyl sulfosuccinate or
sodium lauryl sulfate.
5.1.9
Use
a sterile platinum or nichrome inoculating wire to
scrape gently the surface growth from the culture of the test
organism.
5.1.10
Pour
the spore charge into a sterile 125-ml glass-
stoppered Erlenmeyer flask containing 45 ml of sterile water
and 50 to 75 solid glass beads, 5 mm in diameter.
5.1.11
Shake
the flask vigorously to liberate the spores from
the fruiting bodies and to break the spore clumps.
5.1.12
Filter
the dispersed fungal spore suspension, through
a 6 mm layer of glass wool contained in a glass funnel, into a
sterile flask.
5.1.13 This
process should remove large mycelial fragments
and clumps of agar which could interfere with the spraying
process.
5.1.14
Centrifuge
the filtered spore suspension aseptically
and discard the supernatant liquid.
5.1.15
Resuspend
the residue in 50 ml of sterile water and
centrifuge. Wash the spores obtained from each of the fungi
in this manner three times.
5.1.16
Dilute
the final washed residue with sterile mineral-
salts solution in such a manner that the resultant spore sus-
pension shall contain 1,000,000 ± 200,000 spores per ml as
determined with a counting chamber.
5.1.17 Repeat
this operation for each organism used in the
test and blend equal volumes of the resultant spore suspen-
sion to obtain the final mixed spore suspension. The spore
suspension may be prepared fresh each day or may be held
at 6 ± 4°C [42.8 ± 7.2°F] for not more than seven days.
5.2
Viability of Inoculum Control
With
each daily group
of tests, place each of three pieces of sterilized filter paper, 1
inch square, on hardened mineral-salts agar in separate Petri
dishes. Inoculate these with the spore suspension by spraying
the suspension from a sterilized atomizer until initiation of
droplet coalescence. Incubate these at 30 ± 1°C [86 ± 1.8°F]
at a relative humidity not less than 85% and examine them
after seven days of incubation. There shall be copious growth
on all three of the filter paper control specimens. Absence of
such growth requires repetition of the test.
5.3
Control Items
5.3.1
In
addition to the viability of inoculum control, known
susceptible substrates shall be inoculated along with the test
item to insure that proper conditions are present in the incu-
bation chamber to promote fungus growth.
5.3.2
The
control items shall consist of cotton duck
8.25-ounce strips that are 5 cm, that have been dipped
intoa solution containing 10% glycerol, 0.1% potassium
dihydrogen orthophosphate (KH
2
PO
4
),
0.1% ammonium
nitrate (NH
4
NO
3
),
0.025% magnesium heptahydrate sul-
fate (MgSO
4
•7H
2
O),
and 0.05% yeast extract (pH 5.3),
and from which the excess liquid has been removed.
5.3.3
The
strips should be hung to air dry before being
inoculated and placed into the chamber.
5.4
Inoculation of Test and Control Item
5.4.1
Mount
the test and control items on suitable fixtures or
suspend from hangers. No cleaning of the test item shall be
permitted for 72 hours prior to the beginning of the fungus
test. Equipment handling prior to and during the fungus test
shall be accomplished without contamination of the equip-
ment.
5.4.2
Precondition
the chamber and its contents at: 30 ±
1°C [86 ± 1.8°F] and 95 ± 2% relative humidity for at least four
hours.
5.4.3
Inoculate
the test and control items with the mixed
fungus spore suspension by spraying it on and into the test
and control items (if not hermetically sealed) in the form of a
IPC-TM-650
Number
2.6.1.1
Subject
Fungus
Resistance – Conformal Coating
Date
07/00
Revision
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fine
mist from a previously sterilized atomizer or nebulizer. In
spraying the test and control items, care should be taken to
spray all surfaces which are exposed during use or mainte-
nance. If the surfaces are nonwetting, spray until initiation of
droplet coalescence. Incubation is to be started immediately
following the inoculation.
5.5
Test Incubation of Test Items
5.5.1
Incubate
test items under static temperature of
28-30°C [82.4-86°F] with a minimum 85% relative humidity.
5.5.2
After
seven days, inspect the growth on the control
items to be assured that the environmental conditions are
suitable for growth. If inspection reveals that the environmen-
tal conditions are unsuitable for growth, the entire test shall be
repeated.
5.5.3
If
the control items show satisfactory fungus growth,
continue the test for a period of 28 days from the time of
inoculation, or as specified.
5.6
Evaluation
5.6.1
Report
those specimens which were found to be nutri-
ent to fungus growth.
5.6.2
Corrosion
should be noted separately from the fungus
test results.
6.0 Notes
6.1
Source for Micro-organisms
6.1.1
American
Type Culture Collection
10801 University Blvd.
Manassas, VA 20110-2209 (USA)
703-365-2700
http://www.atcc.org
6.2
Secondary Sources for Microorganisms
6.2.1
Pioneering
Research Division
U.S. Army Natick
Laboratories
Natick, Massachusetts 01760
6.2.2
North
University St.
Peoria, IL 61604
Contact: Dr. Stephen Peterson
309-685-4011
6.3
After
evaluation, the materials and the test chamber
must be decontaminated by exposure on all sides to ultravio-
let rays (360 nm) for a minimum of two hours, or sprayed with
a solution of 1:750 zephiran chloride solution. (One part zephi-
ran chloride to 750 parts distilled water).
6.4
Safety
Observe
all appropriate precautions on MSDS
for chemicals involved in this test method.
IPC-TM-650
Number
2.6.1.1
Subject
Fungus
Resistance – Conformal Coating
Date
07/00
Revision
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