ASTM D178-22

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D178 − 19 D178 − 22
Standard Specification for
Rubber Insulating Matting
This standard is issued under the fixed designation D178; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This specification covers acceptance testing of rubber insulating matting for use as a floor covering for protection of workers.
1.2 Two types of matting, differing in chemical and physical characteristics, are provided and are designated as Type I and Type
II matting.
1.3 The following safety hazards caveat applies only to the test method portion, Sections 17 to 19, of this specification: 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, health, and environmental practices and determine the applicability of regulatory
limitations prior to use.
NOTE 1—Rubber insulating matting should remain flexible for use through normal temperature ranges.
NOTE 2—Rubber as used in this specification is a generic term that includes elastomers and elastomer compounds, regardless of origin.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at
Commercial Power Frequencies
D297 Test Methods for Rubber Products—Chemical Analysis
D412 Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension
D471 Test Method for Rubber Property—Effect of Liquids
D518 Test Method for Rubber Deterioration—Surface Cracking (Withdrawn 2007)
D570 Test Method for Water Absorption of Plastics
D573 Test Method for Rubber—Deterioration in an Air Oven
D1692 Method of Test for Rate of Burning or Extent and Time of Burning of Cellular Plastics Using a Specimen Supported by
a Horizontal Screen (Withdrawn 1976)
This specification is under the jurisdiction of ASTM Committee F18 on Electrical Protective Equipment for Workers and is the direct responsibility of Subcommittee
F18.25 on Insulating Cover-Up Equipment. This standard replaces ANSI Standard J 6.7, which is no longer available.
Current edition approved Jan. 1, 2019Dec. 1, 2022. Published February 2019January 2023. Originally approved in 1923. Last previous edition approved in 20102019 as
D178 – 01D178 – 19.(2010). DOI: 10.1520/D0178-19. 10.1520/D0178-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D178 − 22
2.2 American National Standard:
ANSI C84.1 Voltage Ratings for Electric Power Systems and Equipment (60 Hz)
3. Terminology
3.1 Definitions:
3.1.1 user, n—as used in 4.3.1, the entity employing the actual worker(s) utilizing the equipment; if no separate employer, then
the individual.
3.1.2 voltage, maximum retest, n—voltage, either ac rms or dc avg, which is equal to the proof-test voltage for new protective
equipment.
3.1.3 voltage, retest, n—voltage, either ac rms or dc avg, that used protective equipment must be capable of withstanding for a
specified test period without breakdown.
3.1.4 voltage, nominal design, n—a nominal value consistent with the latest revision of ANSI C84.1, assigned to the circuit or
system for the purpose of conveniently designating its voltage class.
3.1.5 voltage, maximum use, n—the ac voltage (rms) classification of the protective equipment that designates the maximum
nominal design voltage of the energized system that may be safely worked. The nominal design voltage is equal to phase-to-phase
voltage on multiphase circuits.
3.1.5.1 If there is no multiphase exposure in a system area, and the voltage exposure is limited to phase (polarity on dc systems)
to ground potential, the phase (polarity on dc systems) to ground potential shall be considered to be the nominal design voltage.
3.1.5.2 If electrical equipment and devices are insulated, or isolated, or both, such that the multiphase exposure on a grounded wye
circuit is removed, then the nominal design voltage may be considered as the phase-to-ground voltage on that circuit.
4. Significance and Use
4.1 This specification covers the minimum electrical, chemical, and physical properties guaranteed by the manufacturer and the
detailed procedures by which such properties are to be determined. The purchaser may at his option perform or have performed
any of these tests in order to verify the guarantee. Claims for failure to meet the specification are subject to verification by the
manufacturer.
4.2 Rubber insulating matting is used for personal protection; therefore when authorizing its use a margin of safety should be
allowed between the maximum voltage at which it is used and the proof-test voltage at which it is tested. The relationship between
proof-test and the maximum voltage at which matting shall be used is shown in Table 1.
4.3 Work practices vary from user to user, depending upon many factors. These may include, but are not limited to, operating
system voltages, construction design, work procedures and techniques, weather conditions etc. Therefore, except for the
restrictions set forth in this specification because of design limitations, the use and maintenance of this equipment is beyond the
scope of this specificationspecification.
4.3.1 It is common practice and the responsibility of the user of this type of protective equipment to prepare complete instructions
and regulations to govern the correct and safe use of such equipment.
5. Classification
5.1 Matting covered under this specification shall be designated as Type I or Type II; Class 0, Class 1, Class 2, Class 3, or Class
4.
5.1.1 Type I, made of any elastomer or combination of elastomer compounds, properly vulcanized.
Available from American National Standards Institute, 11 West 42nd Street, 13th Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.10036,
http://www.ansi.org.
D178 − 22
TABLE 1 Proof Test/Use Voltage Relationship
NOTE 1—The ac voltage (rms) classification of the protective equip-
ment designates the maximum nominal design voltage of the energized
system that may be safely worked. The nominal design voltage is equal to:
a. The phase to phase on multiphase circuits or
b. The phase to ground voltage on single phase grounded circuits.
Nominal Maximum
A
Class of Insulat- AC Proof-Test DC Proof-Test
Use Voltage
ing Matting Phase-Phase Voltage, rms V Voltage, avg, V
ac rms, max
0 1 000 5 000 20 000
1 7 500 10 000 40 000
2 17 000 20 000 50 000
3 26 500 30 000 60 000
4 36 000 40 000 70 000
A
Except for Class O equipment, the maximum use voltage is based on the
following formula:
Maximum use voltage (maximum nominal design voltage) 0.95 ac proof-test
voltage − 2000
5.1.2 Type II, made of any elastomer or combination of elastomeric compounds with one or more of the following special
properties:
5.1.2.1 A—Ozone resistance
5.1.2.2 B—Flame resistance
5.1.2.3 C—Oil resistance
5.1.3 The class designation shall be based on the electrical properties as shown in Table 2.
6. Ordering Information
6.1 Orders for matting under this specification should include the following information:
6.1.1 Type,
6.1.2 Class,
6.1.3 Thickness,
6.1.4 Width,
6.1.5 Length, and
6.1.6 Color.
TABLE 2 Electrical Test Requirements
A
AC DC
Proof Test Proof Test Dielectric Test
B B
Class Electrode Clearances, min Dielectric Test Voltage Electrode Clearances, min
Voltage Voltage Voltage
mm in. rms V rms V mm in. avg V avg V
0 76 3 5 000 6 000 76 3 20 000 35 000
1 76 3 10 000 20 000 76 3 40 000 60 000
2 127 5 20 000 30 000 152 6 50 000 70 000
3 178 7 30 000 40 000 203 8 60 000 80 000
4 178 10 40 000 50 000 305 12 70 000 90 000
4 254 10 40 000 50 000 305 12 70 000 90 000
A
DC proof-test, voltages were determined using negative polarity.
B
These nominal clearances are intended to avoid flashover and may be increased by no more than 2 in. (51 mm) when required by change in atmospheric conditions
from the standard of 100 kPa (1 atm) barometric pressure and average humidity conditions. These clearances may be decreased if atmospheric conditions permit.
D178 − 22
6.2 The listing of types, classes, thicknesses, widths, lengths, and colors is not intended to mean that all shall necessarily be
available from manufacturers; it signifies only that, if made, they shall conform to the details of this specification.
7. Manufacture and Marking
7.1 The matting shall consist of a rubber compound with a smooth, corrugated, or diamond design on one surface and may be
backed with fabric, or may have one or more fabric inserts. The back of the matting may be finished with cloth imprint or other
slip-resistant material. Any such fabric insert shall not affect adversely the dielectric characteristics of the matting.
7.2 Each piece of matting shall be marked clearly and permanently at a maximum interval of 1 m (3 ft) with the name of the
manufacturer or supplier, ASTM D178, type, and class.
8. Dimensions and Permissible Variations
8.1 Width—Standard widths shall be 610610 mm 6 13 mm (24.0(24.0 in. 6 0.5 in.), 760 6 13 mm (30.0760 mm 6 13 mm
(30.0 in. 6 0.5 in.), 914914 mm 6 25 mm (36(36 in. 6 1 in.) and 12206 1220 mm 6 25 mm (48(48 in. 6 1 in.).
8.2 Thickness—The thickness of the matting shall be as specified in Table 3. Measurements shall be made over the corrugations
or diamonds. The corrugations shall be not more than 3.2 mm (0.125 in.) deep. The diamonds shall not be higher than 1.6 mm
(0.062 in.).
9. Workmanship and Finish
9.1 The matting shall be free of harmful physical irregularities, which can be detected by thorough test or inspection.
9.1.1 Nonharmful Irregularities—Surface irregularities may be present on all rubber matting due to imperfections in molds and
inherent difficulties in the manufacturing processes. These irregularities may appear as indentations, protuberances, or imbedded
foreign material that are acceptable provided that:
9.1.1.1 The indentation or protuberance tends to blend into a smooth slope upon stretching of the material.
9.1.1.2 The rubber thickness at any irregularity conforms to the thickness requirements.
9.1.1.3 Foreign material remains in place when the matting is bent and stretches equally with the material surrounding it.
10. Chemical and Physical Requirements
10.1 Insulating matting shall conform to the physical requirements in Table 4. For Type II matting, flame or oil resistance can be
determined by conducting the tests in 19.2.5 or 19.2.6, respectively.
11. Electrical Requirements
11.1 The entire length of each roll of matting when new (unused) shall withstand the 50/60-Hz ac proof-test voltage (rms value)
or the dc proof-test voltage (average value) specified in Table 2. The test voltage shall be applied continuously for 1 min.
TABLE 3 Thickness Measurements
Thickness Tolerance
Class
mm in. mm in.
0 3.2 0.13 0.8 0.03
1 4.8 0.19 0.8 0.03
2 6.4 0.25 0.8 0.03
3 9.5 0.38 1.2 0.05
4 12.7 0.50 1.2 0.05
D178 − 22
TABLE 4 Physical Requirements
Type I Type II
Tensile strength, min, MPa (psi) 4.83 (700) 4.83 (700)
Tension set, max, at 150 % elongation, 12.7 (0.50) 12.7 (0.50)
51-mm (2-in.) bench mark, mm (in.)
Tension set, max, at 150 % elongation, 12.7 (0.50) 12.7 (0.50)
51 mm (2-in.) bench mark, mm (in.)
Elongation, min, % 250 250
A
Moisture absorption, max in-crease , 1 ⁄2 3
%
Flame resistance, Type IIB not applicable 12.7 mm (0.5 in.)
after 30 s
Oil resistance, max, volume increase, not applicable 4
B
Type IIC
A
Distilled water—23°C (75°F).water—23 °C (75 °F).
B
ASTM Oil No. 2 room temperature for 24 h.
11.2 The matting material when tested between 50-mm50 mm (2-in.) disk electrodes with edges rounded to a radius of 6 mm
6 mm (0.25 in.), shall show a 50/60-Hz dielectric strength of not less than the requirements shown in Table 2 for the thickness of
each individual specimen.
11.3 The Type IIA matting material shall show no visible effects from ozone when tested in accordance with 18.6.1, or 18.6.2.
In case of dispute, Method A of the ozone resistance test shall be the referee test.
12. Guarantee
12.1 The manufacturer or supplier shall replace, without charge to the purchaser, unused matting which, at any time within a
period of nine (9) months from date of initial delivery of shipment to the purchaser or his designee, fail to pass the tests in this
specification. This guarantee will be binding on the manufacturer or supplier only if the matting has been properly stored and has
not been subjected to more than an original acceptance test and one retest.
12.2 Any acceptance test made by the purchaser, or the purchaser’s designee, shall be performed within the first two (2) months
of the guarantee period unless otherwise specified.
NOTE 3—Proper storage means that the matting is stored without distortion, and not stored directly above or in proximity to steam pipes, radiators, or
other sources of artificial heat, or exposed to direct sunlight or sources of ozone. It is desirable that the ambient storage temperature shall not exceed 35°C
(95°F).35 °C (95 °F).
13. Sampling
13.1 Each roll of matting in a lot or shipment shall be subject to inspection and test by the manufacturer including electrical proof
test to levels required in Table 2 of this specification.
13.2 An original sample of sufficient material shall be cut from the end of a roll or rolls selected from the lot for the test
requirements of Section 10, 11.2, and 11.3. A lot is defined as that quantity of material produced by a common manufacturing
process during a consecutive time period not to exceed 24 h. If failure occurs in the first sample, a second sample of the same
quantity shall be selected and tested.
14. Rejection
14.1 Individual rolls shall be rejected if they fail to meet the manufacturing and marking requirements of Section 7, the electrical
requirements of 11.1, the width requirements of 8.1, the minimum thickness requirements of 8.2, or the workmanship requirements
of Section 9.
14.2 The entire lot or shipment of matting shall be rejected under any of the following conditions:
14.2.1 If 5 % or more, but not less than two rolls of the matting, in a shipment fail to meet the requirements of 11.1.
D178 − 22
14.2.2 If two dielectric breakdowns that do not meet the dielectric strength value specified in 11.2 occur in five tests on the
specimen.
14.2.3 If one dielectric breakdown of five tests on the original and one or more dielectric breakdowns of five tests on an additional
specimen fail to meet the dielectric strength value specified in 11.2.
14.2.4 If the sample specimens of Type IIA matting, using the sampling methods and criteria specified in 18.6.1 or 18.6.2, fail to
meet the ozone resistance requirements of 11.3.
14.2.5 If the sample specimens of Type IIB matting using the sampling methods and criteria specified in 19.2.5, fail to meet the
flame-resistant requirements of 10.1.
14.2.6 If the sample specimens of Type IIC matting using the sampling methods and criteria specified in 19.2.6 fail to meet the
oil resistance requirements of 10.1.
14.3 The testing shall be terminated and the manufacturer or supplier notified if, during the course of testing, 5 % or more, but
not less than two rolls, of the matting in a lot or shipment, fail to meet the requirements of 11.1, 11.2, or 11.3 as determined by
the rejection criteria of 14.1, 14.2, 14.2.1, 14.2.2, 14.2.3, 14.2.4, 14.2.5, or 14.2.6. The manufacturer or supplier may in such a case
require the purchaser to submit proof that the test procedure and equipment conform to the appropriate paragraphs of Section 18.
When such proof has been furnished, the manufacturer or supplier may request that his representative witness the testing of
additional rolls from the shipment.
14.4 The entire lot or shipment of matting may be rejected at the option of the purchaser if two of the five specimens tested fail
any of the separate requirements outlined in Section 10.
14.5 The entire lot or shipment of matting may be rejected at the option of the purchaser if 25 % of the matting in the lot or
shipment fail to meet the requirements of Section 8 or 9.
14.6 All rejected material shall be returned unaltered except as required for sampling, as directed by the manufacturer at his or
the supplier’s request. However, those mats punctured when tested in accordance with 11.1 or 11.2 shall be stamped, punched, or
cut prior to being returned to the supplier to indicate that they are unfit for electrical use.
15. Packaging
15.1 Matting shall be packaged either flat or in rolls and shall not be distorted mechanically.
16. Thickness Measurements
16.1 Thickness measurements should be made on complete matting samples with a caliper graduated to within 0.03 mm (0.001
in.). At least five thickness measurements shall be made at selected points uniformly distributed over the test area of the matting.
TEST METHODS
17. Sequence of Testing
17.1 The following order of procedure is suggested for testing rubber insulating matting.
17.1.1 Inspection of the surfaces in accordance with Section 9.
17.1.2 The dimensions in accordance with Sections 8 and 16.
17.1.3 Electrical proof test in accordance with the appropriate paragraphs of Section 18.
17.1.4 Breakdown voltage test in accordance with the appropriate paragraphs of Section 18.
17.1.5 Ozone resistance tests in accordance with the appropriate paragraphs of Section 18.
D178 − 22
17.1.6 Chemical and physical property tests in accordance with Section 19.
18. Electrical Tests
18.1 Conditioning—Prior to testing, the matting shall be made in a flat position.
NOTE 4—Both ac and dc proof-test methods are included in this section. It is intended that one method be selected for the electrical acceptance tests. The
method selected shall be at the option of the purchaser, and the supplier should be so notified of the selection.
18.2 Warning—It is recommended that the test apparatus be designed to afford the operator full protection in the performance
of his duties. Reliable means of de-energizing and grounding the high-voltage circuit should be provided. It is particularly
important to incorporate a positive means of grounding the high-voltage section of dc test apparatus due to the likely presence of
high-voltage capacitance charges at the conclusion of the test.Warning—It is recommended that the test apparatus be designed to
afford the operator full protection in the performance of his duties. Reliable means of de-energizing and grounding the high-voltage
circuit should be provided. It is particularly important to incorporate a positive means of grounding the high-voltage section of dc
test apparatus due to the likely presence of high-voltage capacitance charges at the conclusion of the test.
18.3 AC Proof Test:
18.3.1 Electrodes—Where electrodes are to be employed as part of the test apparatus, they shall be of such design so as to apply
the electrical stress uniformly over the test area without producing corona at any point, or mechanical strain in the material. The
electrodes used in proof tests shall be of such dimensions that the flashover clearances specified in Table 2 are not exceeded. A
satisfactory procedure for ac proof testing utilizes electrodes that will provide intimate contact without undue pressure.
NOTE 5—Rectangular metal sheets approximately 3 mm (0.06 in.) thick, having smoothly rounded edges and corners, have been found to be satisfactory
for this purpose. Also satisfactory are wet felt or sponge-top electrodes.
18.3.2 Voltage Supply and Regulation:
18.3.2.1 The test equipment used in both the proof-test voltage and dielectric breakdown voltage tests shall be capable of
supplying an essentially stepless and continuously variable voltage to the test specimen. Motor-driven regulating equipment is
convenient and tends to provide uniform rate-of-rise to the test voltage. The test apparatus should be protected by an automatic
circuit-breaking device designed to open promptly on the current produced by breakdown of a specimen under test. This circuit
breaking device should be designed to protect the test equipment under any conditions of short circuit.
18.3.2.2 The desired test voltage may be obtained most readily from a step-up transformer energized from a variable low-voltage
source. The transformer and its control equipment shall be of such size and design that, with the test specimen in the circuit, the
crest factor (ratio of maximum to mean effective) of the test voltage shall differ by not more than 5 % from that of a sinusoidal
wave over the upper half of the range of test voltage.
18.3.2.3 The accuracy of the voltage measuring circuit shall be within 61 kV of the test voltage. The AC voltage applied to the
test specimen shall be measured with either an AC voltmeter (RMS or average responding) or a peak responding voltmeter
calibrated to pk/SQRT2 using one of the following methods: (1) a voltmeter used in conjunction with a calibrated instrument
transformer connected directl
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