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MT 141-2005: Plastic net protecting top-plane in coal mining
MT 141-2005
MT
COAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 23.040.20;83.140.30
G 33
Registration number. 16782-2005
Replacing MT 141-1986
Plastic net protecting top-plane in coal mining
ISSUED ON. SEPTEMBER 23, 2005
IMPLEMENTED ON. FEBRUARY 01, 2006
Issued by. National Development and Reform Commission
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Table of contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Top-plane protection plastic net model ... 4 
4 Requirements ... 4 
5 Test methods ... 6 
6 Inspection rules ... 14 
7 Marking, packaging, transportation and storage ... 15 
Appendix A (Normative) General specifications of plastic net protecting
top-plane ... 17 
Foreword
Clause 4.4, 4.5, 4.6, 4.7, 4.8 and 4.9 of this standard are mandatory, AND
the rest is recommended.
This standard is the revision of MT 141-1986 “Specification for inspection of
plastic net protecting top-plane in coal mining”. AND this standard replaces MT
141-1986 from the date of implementation.
As compared with MT 141-1986, the main changes of this standard are as
follows.
- ADD the tensile strength requirements (SEE 4.7);
- ADD the determination of the flame temperature of the alcohol torch (SEE
5.7.3.3);
- ADD the Appendix A;
- MODIFY the model preparation method (clause 1.1 of 1986 version;
clause 3 of this version);
- MODIFY the preparation of the sample the surface of which is coated with
a conductive layer (clause 9.2 of 1986 version; clause 5.6.1.1 of this
version);
- DELETE the contents of the fuel consumption amount (clause 5.2.5 of
1986 version);
- CANCEL the requirements for the width and thickness of plastic net
(clause 2.2.1 and 2.2.2 of 1986 version).
Appendix A of this standard is normative.
This standard was proposed by China Coal Industry Association Science and
Technology Development Department.
This standard shall be under the jurisdiction of the Coal Industry Coal Mine
Safety Standardization Technical Committee.
The drafting organization of this standard. Coal Science Research Institute
Shanghai Branch.
The main drafters of this standard. Ju Qinghua, Zheng Qi, Jiang Naiqiang,
Yuan Kailiang.
This standard was first published in July 1986.
Plastic net protecting top-plane in coal mining
1 Scope
This standard specifies the product model, requirements, test methods,
inspection rules, marking, packaging, transportation and storage of the plastic
net protecting top-plane in coal mining (hereinafter referred to as top-plane
protection net).
This standard applies to plastic net protecting top-plane in coal mining.
2 Normative references
The provisions in following documents become the provisions of this Standard
through reference in this Standard. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this Standard;
however, parties who reach an agreement based on this Standard are
encouraged to study if the latest versions of these documents are applicable.
For undated references, the latest edition of the referenced document applies.
MT 182-1998 Alcohol blast burner structure and technical requirements
MT 113-1995 General test methods and judgment rules for fire-resistant
antistatic properties of polymer products for coal mine
3 Top-plane protection plastic net model
The model of the top-plane protection net is divided into 160MS, 180MS,
200MS, 220MS, 240MS, 260MS and 280MS in accordance with the single
cross section tensile strength. Model example is as follows.
4 Requirements
4.1 Appearance quality
Indicates flame-retardant and anti-electrostatic
Indicates plastic net protecting top-plane
Indicates single cross-section tensile strength, in Megapascal (MPa)
Indicates materials
b) If started time keeping from the time when the sample flame is
extinguished, the arithmetic mean of the flameless combustion time of
the 6 samples shall be less than 10 s, wherein the single value of the
flameless combustion time of any one of the samples shall be less than
30 s.
4.9.2 Alcohol lamp combustion performance
The top-plane protection net shall, through the alcohol lamp combustion test,
comply with the following requirements.
a) After removing the alcohol lamp, the arithmetic mean of the flame
combustion time of the 6 samples shall be less than 6 s, wherein the
single value of the flame combustion time of any one of the samples shall
be less than 12 s.
b) If started time keeping from the time when the sample flame is
extinguished, the arithmetic mean of the flameless combustion time of
the 6 samples shall be less than 10 s, wherein the single value of the
flameless combustion time of any one of the samples shall be less than
30 s.
4.10 Specifications of top-plane protection plastic net
The general specifications of the top-plane protection plastic net are as shown
in Appendix A.
5 Test methods
5.1 Sample preparation
After the product was made 24 h, TAKE the sample.
5.2 Appearance quality
CUT one piece of sample having a length of not less than 10 m; PERFORM
visual inspection.
5.3 Specification size inspection
CUT one piece of sample having a length of 1m; USE a Vernier caliper having
a precision of 0.02 mm to measure width at any 5 points along the parallel
direction; TAKE the arithmetic mean; LEAVE 2 places after the decimal point;
ROUND off to 1 place after the decimal point; USE a Vernier caliper having a
precision of 0.02 mm to measure thickness at any 5 points; TAKE the
arithmetic mean; LEAVE 2 places after the decimal point; ROUND off to 1
place after the decimal point.
5.4 Skewness test
c) Respectively CALCULATE the tensile strength and tensile elongation at
fracture of each group of 5 samples, and CALCULATE the arithmetic
mean of the tensile strength and the tensile elongation at fracture of each
group of samples, TAKE the integer.
5.6 Surface resistance test
5.6.1 Sample preparation
5.6.1.1 TAKE a certain number of top-plane protection nets; USE the hot
pressing method to prepare them into circular or square sheet samples the
surface of which is flat and smooth; the sample thickness is (1 ± 0.2) mm, the
sample diameter or edge length is not less than 100 mm, and the number of
sample is 3; AND if the sample surface is coated with conductive layer, it shall
arrange the top-plane protection nets in parallel into square sample, AND
press it flatly before using it as the sample for the measurement of the surface
resistance.
5.6.1.2 USE the clean silk cloth or sterilized cotton cloth which is dampened
with distilled water to clean the sample; then USE a clean dry cloth to wipe the
sample dry; PLACE it in a dry place for over 24 h; before the arbitration test,
PLACE the sample in a dry place for 7 days before making the test.
5.6.1.3 Before the test, PLACE the sample in an environment having a
temperature of (25 ± 5) °C and a relative temperature of 60% ~ 70% for at least
2 h.
5.6.2 Conductive liquid
The composition of the conductive liquid (mass percentage) is.
Anhydrous polyethylene glycol having a molecular weight of 600. 79.9%
Soft soap. 0.1%
Water. 20.0%
5.6.3 Instrument
5.6.3.1 Surface resistance tester.
The measuring range is 103 ~ 1010 Ω, the accuracy is 10%, the DC powe...