ASTM D5485-99
(Test Method)Standard Test Method for Determining the Corrosive Effect of Combustion Products Using the Cone Corrosimeter
Standard Test Method for Determining the Corrosive Effect of Combustion Products Using the Cone Corrosimeter
SCOPE
1.1 This fire-test-response standard measures the corrosive effect by loss of metal from the combustion products of materials, components, or products.
1.2 This test method provides corrosion results of product and material specimens limited to a maximum size of 100 by 100 mm in area and 50 mm thick.
1.3 The results of this test method have not been investigated with respect to correlation to actual fires.
1.4 This standard should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use.
1.4.1 Additional information regarding the targets, the test conditions, and test limitations are provided in the annex.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 7.
1.6 The values stated in SI units are the standard (see Practice E380.
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Standards Content (Sample)
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An American National Standard
Designation:D5485–99
Standard Test Method for
Determining the Corrosive Effect of Combustion Products
Using the Cone Corrosimeter
This standard is issued under the fixed designation D5485; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope IEEE/ASTM SI-10 Standard for Use of the International
System of Units (SI): The Modern Metric System
1.1 This fire-test-response standard measures the corrosive
2.2 Other Document:
effect by loss of metal from the combustion products of
OSHA 191.1450 Occupational Exposure to Hazard Chemi-
materials, components, or products.
cals in Laboratories
1.2 This test method provides corrosion results of product
and material specimens limited to a maximum size of 100 by
3. Terminology
100 mm in area and 50 mm thick.
3.1 Definitions:
1.3 The results of this test method have not been investi-
3.1.1 For definitions of terms used in this test method, refer
gated with respect to correlation to actual fires.
to Terminologies E176 and D1711.
1.4 This standard measures and describes the response of
3.2 Definitions of Terms Specific to This Standard:
materials, products, or assemblies to heat and flame under
3.2.1 cone corrosimeter, n—equipment used to determine
controlled conditions, but does not by itself incorporate all
corrosion in this test method.
factors required for fire hazard or fire risk assessment of the
3.2.2 corrosion-by-metal-loss, n—loss of metal of a target
materials, products, or assemblies under actual fire conditions.
expressed as reduction of thickness of the target metal.
1.4.1 Additional information regarding the targets, the test
3.2.3 exposure chamber, n—enclosure in which a target is
conditions, and test limitations are provided in the annex.
exposed to combustion products.
1.5 This standard does not purport to address all of the
3.2.4 heating flux, n—incident power per unit area that is
safety concerns, if any, associated with its use. It is the
imposed externally from the heater on the specimen.
responsibility of the user of this standard to establish appro-
3.2.4.1 Discussion—The specimen, once ignited, is also
priate safety and health practices and determine the applica-
heated by its own flame.
bility of regulatory limitations prior to use. For specific hazard
3.2.5 sustained flaming, n—existence of flame on or over
statements, see Section 7.
the surface of the test specimen for periods of4sor more.
1.6 The values stated in SI units are the standard (see
3.2.5.1 Discussion—Flaming ignition of less than4sis
IEEE/ASTM SI 10 .
identified as transitory flaming or flashing.
2. Referenced Documents 3.2.6 target, n—detector of known electrical resistance
which can lose metal through a process of corrosion when it is
2.1 ASTM Standards:
2 exposed to combustion products.
D618 Practice for Conditioning Plastics for Testing
3.3 Symbols Specific to This Standard:
D1711 Terminology Relating to Electrical Insulation
4 3.3.1 A —initial corrosion instrument reading.
E176 Terminology of Fire Standards
3.3.2 A —corrosion instrument reading at the end of 1-h
E1354 Test Method for Heat and Visible Smoke Release
exposure to combustion products.
Rates for Materials and Products Using an Oxygen Con-
3.3.3 A —corrosion instrument reading at the end of 24 h
sumption Calorimeter
in the environmental chamber.
3.3.4 C—corrosion of a target, nm.
3.3.5 C —corrosion at the end of 1-h exposure to combus-
This test method is under the jurisdiction of ASTM Committee D09 on
tion products, nm.
Electrical and Electronic Insulating Materials and is the direct responsibility of
3.3.6 C —corrosionattheendof24hintheenvironmental
Subcommittee D09.21 on Fire Performance Standards.
chamber, nm.
Current edition approved Oct. 10, 1999. Published December 1999. Originally
published as D5485–94. Last previous edition D5485–94a.
Annual Book of ASTM Standards, Vol 08.01.
3 5
Annual Book of ASTM Standards, Vol 10.01. Annual Book of ASTM Standards, Vol 14.02.
4 6
Annual Book of ASTM Standards, Vol 04.07. Available from Occupational Safety and Health Agency.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D5485
3.3.7 m—specimen mass, g. 5. Significance and Use
3.3.8 m—final specimen mass, g.
f
5.1 The metal loss from corrosion is directly related to the
3.3.9 m—initial specimen mass, g.
increaseinelectricalresistanceofthetargetduetothedecrease
i
3.3.10 m —average 70% of the total mass loss, g. in conductive cross-sectional area.
3.3.11 t —sampling time, s. 5.2 The relationship between resistance increase of metallic
d
targetsusedinthistestmethodandtheamountofmetallossas
3.3.12 T —temperature of the gas in the exposure chamber,
e
reported by a uniform loss in thickness has not been deter-
°C.
mined.
3.3.13 V—volumetric sampling rate of combustion prod-
5.3 This test method is used to determine the corrosive
ucts, m /s.
effect of combustion products from burning electrical insula-
tionsorcoveringsortheirconstituentmaterialsorcomponents.
4. Summary of Test Method
Corrosion is determined by the reduction of thickness of the
4.1 In this test method, a specimen is subjected to radiant
metal on standardized targets, as measured by electrical resis-
heat. A spark igniter is used to ignite the combustible vapors.
tance. These targets are not necessarily representative of the
The products of decomposition or combustion are channeled
intended end use.
through a funnel.Aportion of the products continuously flows
5.4 This test method is intended for use in electrical
throughanexposurechamberwhichholdsthecorrosiontargets
insulations or coverings material and product evaluations, for
until the specimen has lost an average 70% of the total
additional data to assist in design of electrical insulations or
combustible mass or for a period of 60 min, whichever is less.
coverings products, or for development and research of elec-
The corrosion of the target is determined by exposure of the
trical insulations or coverings products.
target to combustion products for 1 h, followed by 24-h
5.5 A value of the heating flux is selected to be relevant to
exposureofthetargettoacontrolledhumidityandtemperature
the fire scenario being investigated (up to 100 kW/m ).
environment in a separate chamber. The increase in electrical
Additional information for testing is given in A1.2.3.
resistance of each target is monitored, and the reduction in
thickness of the metal on the target is calculated from the
6. Interferences
increase in electrical resistance. This reduction in thickness is
referred to as corrosion-by-metal-loss.
6.1 Discard the test data if any of the following occur:
4.2 Thistestmethodinvolvestheuseofaconecorrosimeter 6.1.1 Leakage occurs between the sampling point and the
as described in Section 7 and shown in Fig. 1. exit of the exposure chamber which could cause a dilution of
gases.
4.3 Alternate equipment found suitable for this test method
is the cone calorimeter (see Test Method E1354), with the 6.1.2 The specimen swells sufficiently prior to ignition to
addition of the gas sampling system described in this test touch the spark plug or swells into the plane of the heater base
method. plate during combustion.
FIG. 1 Cone Corrosimeter
D5485
6.1.3 The specimen drips off the specimen holder or falls stainless-steel-sheathed thermocouples having an outside di-
out of the specimen holder such that the specimen is not ameter of 1.5 to 1.6 mm with an unexposed hot junction.
subjected to the test exposure conditions. Alternatively, either 3-mm outside diameter sheathed thermo-
6.1.4 There is highly localized corrosion of the target, couples with an exposed hot junction, or 1-mm outside
indicating a defective target. diameter sheathed thermocouples with an unexposed hot junc-
6.1.5 There is visual degradation of the reference circuit by tion are suitable. They are symmetrically disposed and in
the attack of combustion products on or under the protective contactwith,butnotweldedto,theheaterelement(seeFig.2).
coating. The thermocouples are of equal length and wired in parallel to
the temperature controller.
7. Apparatus
7.3 Temperature Controller:
7.1 General:
7.3.1 Thetemperaturecontrollerfortheheateristoholdthe
7.1.1 This test method uses the cone corrosimeter described
element temperature steady to within 62°C. A suitable tem-
in 7.1.3. Alternatively, the cone calorimeter test equipment is
perature controller system is a “3-term” controller (propor-
acceptable provided that it is equipped with a gas sampling
tional, integral, and derivative) with a thyristor unit capable of
system as described in 7.8.
switching currents up to 25 A at 240 V.
7.1.2 The dimensions of the cone corrosimeter specimen
7.3.2 Thecontrollerhasatemperatureinputrangefrom0to
holder and additional equipment used in collection of gas
1000°C; a set scale with a resolution of 2°C; and automatic
samples are given in Figs. 1-8 and also stated in the following
cold junction compensation. The controller is equipped with a
description.
safety feature such that in the event of an open circuit in the
7.1.3 The cone corrosimeter consists of the following main
thermocouple line, it will cause the temperature to fall to near
components: conical-shaped radiant electric heater; tempera-
the bottom of its range.
ture controller; load cell; electric ignition spark plug; heat-flux
7.3.3 The temperature controller uses a zero-crossing-type
gage; exhaust system; specimen holder; and the gas sampling
thyristor unit.
system. Other essential elements needed to measure corrosion
7.3.4 Theheatertemperatureismonitoredbyameterwitha
are a corrosion target and a device to measure corrosion (see
resolution of 2°C.
7.9).Ageneral view of the cone corrosimeter is shown in Fig.
7.4 Exhaust System:
1.
7.4.1 Theexhaust-gassystemconsistsofahigh-temperature
7.2 Conical Heater:
centrifugal exhaust blower, a hood, intake and exhaust ducts
7.2.1 The active element of the heater consists of an
for the fan, and an orifice plate flowmeter (Fig. 3).
electrical heater rod, rated at 5000 W at 240 V, tightly wound
7.4.2 The flow rate is determined by measuring the differ-
into the shape of a truncated cone (Fig. 2). The heater is
ential pressure across a sharp-edged orifice (57-mm inside
encased on the outside with a double-wall stainless steel cone,
diameter) in the exhaust stack, at least 350 mm downstream
and packed with a refractory fiber material of approximately
from the fan.
100-kg/m density.
7.2.2 The heater is capable of producing heating flux on the 7.4.3 In other details, the geometry of the exhaust system is
surface of the specimen of up to 100 kW/m with a uniformity not critical. Where necessary, small deviations from the rec-
of 62%withinthecentral50by50-mmareaofthespecimen. ommended dimensions given in Fig. 3 are allowed. For
7.2.3 The heating flux from the heater is held at a preset example,itispermissiblefortheinnerdiameteroftheductand
level by means of a temperature controller and three Type K the orifice plate to be slightly different (tolerance: 62 mm).
FIG. 2 Cross-Section View Through the Heater
D5485
FIG. 3 Exhaust System
steelandhasdimensionsof109by109mm(62mm).Thegrid
has 1-mm ribs and the openings in the center are 19 by 19 mm
(61 mm). The edge frame is constructed from 2-mm nominal
stainless steel with outside dimensions of 116 by 116 by
56-mmheight(62mm).Theframehasan8-mmliponthetop
to provide an opening of 100 by 100 mm on the top.There are
two 3-mm (60.5 mm) diameter by 130-mm (63 mm) long
retaining pins to lock the test specimen in the edge frame.
7.6.2 The bottom is lined with a layer of a low-density
(nominal density 65 kg/m ) refractory fiber blanket with
thickness of at least 13 mm. The distance between the bottom
of the radiant heater and the top of the edge frame is adjusted
to 25 61 mm by using the sliding height adjustment (Fig. 2).
7.7 Ignition Circuit:
7.7.1 Externalignitorisasparkplugpoweredfroma10-kV
transformer. The spark plug has a gap of 3 mm. The trans-
former is of a type specifically designed for spark-ignition use.
The transformer has an isolated (ungrounded) secondary to
minimize interference with the data-transmission lines. The
electrode length and location of the spark plug is such that the
FIG. 4 Exploded View of Load Cell and Cone Radiant Heater
spark gap is located 13 mm above the center of the specimen.
7.8 Gas Sampling System:
ThelocationofthefaninFig.3shallbebetween900and1200
7.8.1 The gas sampling system consists of a conical funnel,
mm downstream of the hood. Flow through the fan ensures
stainless steel tubing, electric heating tape, silicone rubber
adequate mixing, which is essential to the test.
tubing, filter, flowmeter, exposure chamber, target support
7.5 Load Cell—The general arrangement of the load cell
stand, and pump.The general arrangement of the gas sampling
with the conical heater is shown in Fig. 4. Use a load cell with
system is shown in Fig. 1.
an accuracy of 0.1 g, a measuring range of at least 500 g, and
7.8.2 Funnel—The funnel is a truncated cone constructed
a mechanical tare adjustment range of 3.5 kg.
from stainless steel having a larger diameter of 173 6 5 mm,
7.6 Specimen Holder and Mounting:
a smaller diameter of 60 6 5 mm, and a height of 97 6 5 mm.
7.6.1 A specimen holder consists of the bottom, the edge
frame, retaining pins, and wire grid as shown in Fig. 5. The
bottom is constructed from 2-mm nominal stainless steel and
A refractory blanket, RT8 ceramic fiber, Cer-Wool, manufactured by Premier
has outside dimensions of 111 by 111 by 24-mm height (62
Refractories and Chemicals, Inc., King of Prussia, PA, is suitable for this
mm). The grid is constructed from 1-mm nominal stainless application.
D5485
FIG. 5 Specimen Holder
It stands on 57 6 5-mm legs projecting from the larger 7.8.6 Exposure Chamber—The exposure chamber consists
3 10
diameter end. The funnel is shown in Fig. 6. ofa0.0112 60.0005-m polycarbonatechamber, acorrosion
7.8.3 Rigid Tubing—A 6.3-mm (0.25-in.) outside diameter probe support stand, and smoke baffle. The chamber has an
by 675 6 75-mm long stainless steel tube draws a gas sample O-ringsealandinletandoutletports.Thecorrosionchamberis
from the combustion stream. One end of the tube is bent with shown in Fig. 7.
the open end of the tube facing away from the specimen
...
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