GB/T 2408-2021Plastics - Determination of burning characteristics - Horizontal and vertical test (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020,

Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents.

This document replaces GB/T 2408-2008, Plastics - Determination of burning

characteristics - Horizontal and vertical test. Compared with GB/T 2408-2008, the

main technical changes, except editorial changes, are as follows.

a) Modify some contents of Terms and definitions (see Chapter 3; Chapter 3 of the

2008 edition);

b) Modify the arrangement of the chapters of "Test specimen", "Method A" and

"Method B", and add relevant information to test specimen dimensions (see

Chapter 7, Chapter 8 and Chapter 9; Chapter 7, Chapter 8 and Chapter 9 of the

2008 edition);

c) Modify the horizontal burning classification (see 8.4; 8.4 of the 2008 edition);

d) Add information on thickness to material classification [see 8.5m) and 9.5l)];

e) Add evaluation criteria for "burned to the holding clamp" (see 9.2.4);

f) Delete the figure of "Burner/operator/test specimen orientation" (Figure 6 of the

2008 edition);

g) Add the figures of "Clearance gauge", "Flame application", "Flame application

when there are molten drips", "HB specimen gauge", "V specimen gauge

(example)", "Flame front position not classified as 'burned to the holding clamp'"

and "Flame front position classified as 'burned to the holding clamp'" (see Figure

6 ~ Figure 12).

This document uses the redrafting method to modify and adopt IEC 60695-11-10.2013

Fire hazard testing - Part 11-10.Test flames - 50 W horizontal and vertical flame test

methods.

The main technical differences, except editorial changes, between this document and

IEC 60695-11-10.2013, and their reasons are as follows.

a) With regard to the normative references, this document makes technical

adjustments to adapt to the technical conditions of China. The adjustments are

concentrated in Chapter 2 "Normative references". The specific adjustments are

as follows.

* Use GB/T 5169.22-2015 which is equivalent to the international standard to

replace IEC 60695-11-4.2011 (see 6.2, 8.2.3, 9.2.2 and 9.2.3);

* Use GB/T 5471-2008 which is equivalent to the international standard to

replace ISO 295.2004 (see 7.1);

* Use GB/T 9352-2008 which is equivalent to the international standard to

replace ISO 293.2004 (see 7.1);

* Use GB/T 12006.1-2009 which is equivalent to the international standard to

replace ISO 307.2007 (see 9.4);

* Use GB/T 17037.1-2019 and GB/T 17037.5-2020 which modify and adopt

international standards to replace ISO 294 (all parts) (see 7.1);

* Use GB/T 2918-2018 to replace ISO 291.2008 (see the note of 6.7), and move

it to the references;

* Delete the ISO/IEC guideline 51 and the ISO/IEC guideline 104.

b) Delete the terms of "as received", "combustion", "enclosure", "fire hazard

assessment", "fire retardant", "fire risk", "flame" and "ignition", because such

nouns are general terms and some of them are indicated with the forms like verb

or noun, which is inconsistent with the requirements for national standards.

c) Modify horizontal burning classification to "The materials shall be classified as

HB or HB below, as well as HB40 or HB75" instead of "The materials shall be

classified HB, HB40 or HB75", because c in the requirements for HB

classification partly coincides with c in the requirements for HB40 and HB70,

while c in the requirements for HB40 is obviously differentiated from that for

HB70; so, this modification is made to better guide the criteria for classification

(see 8.4).

For convenience of use, this document also makes the following editorial changes.

a) Change the standard name from "Fire hazard testing - Part 11-10.Test flames - 50

W horizontal and vertical flame test methods" to "Plastics - Determination of

burning characteristics - Horizontal and vertical test".

b) Change "electrotechnical products" in the Scope to "plastic and non-metallic

materials".

This document was proposed by China Petroleum and Chemical Industry Federation.

This document shall be under the jurisdiction of National Technical Committee 15 on

Plastic of Standardization Administration of China (SAC/TC 15).

Drafting organizations of this document. China Bluestar Chengrand Co., Ltd., Chengdu

Kingfa Science & Technology New Material Co., Ltd., Shandong Dawn Polymer Co.,

Ltd., Guangzhou Quality Supervision and Testing Institute, Nanjing Jiangning

Analytical Instrument Co., Ltd., Weihai Lianqiao New Material Science and

Technology Co., Ltd., Huafon Group Ltd., Xiamen Defenghang Plastic Industry Co.,

Ltd., Shenzhen CST Standards Technology Co., Ltd., Fujian Inspection and Research

Institute for Product Quality, CGN Juner (Zhejiang) New Materials CO., LTD.,

Liaocheng University, Qingdao Dagang Customs of P. R. China, Jilin Product Quality

Supervision and Inspection Institute.

Chief drafting staffs of this document. Cao Jinpeng, Wang Lin, Zhao Lei, Li Xiaozeng,

Zheng Ning, Wang Fuhai, Li Hongjie, Zhang Guoqiang, Huang Zhiqin, Zhao Yufen,

He Yang, Zhang Lei, Teng Mouyong, Gao Jianguo, Li Shangyu, Xie Peng, Zheng

Mingjia, Li Yetian, He Guoshan, Qi Ji, Guo Yingying.

This document was first published in 2008, and this is the first revision.

Plastics - Determination of burning characteristics -

Horizontal and vertical test

1 Scope

This document specifies small-scale laboratory test procedures intended to compare the

burning behaviour of different materials used in plastic and non-metallic materials

when vertically or horizontally oriented test bar specimens are exposed to a small flame

ignition source with a nominal thermal power of 50 W. These test methods determine

either the linear burning rate or the self-extinguishing properties of materials.

2 Normative references

The following documents are normatively referenced in this document and are

indispensable for its application. For dated references, only the version corresponding

to that date is applicable to this document; for undated references, the latest version

(including all amendments) is applicable to this document.

GB/T 5169.22-2015, Fire hazard testing for electric and electronic products - Part

22 Test flames - 50 W flame - Apparatus and confirmational test method (IEC

60695-11-4.2011, IDT)

3 Terms and definitions

The following terms and definitions are applicable to this document.

Physical object or condition with a potential for an undesirable consequence from fire.

Ability of a material or product to burn with a flame under specified conditions.

Length of material burned per unit time under specified conditions.

4 Principle

Fix a rectangular bar-shaped test specimen to a horizontal or vertical fixture by one end

and expose the free end to a specified test flame. Assess the burning behaviour of the

horizontally supported bar under specific test conditions by measuring the linear

burning rate.

5 Significance of the fire tests

The significant feature of these fire test methods is the arrangement of the test

specimens in either a horizontal or a vertical position. These testing arrangements make

it possible to distinguish between different classes of material flammability.

Burning behaviour, as measured by these test methods, is affected by such factors as

density, any anisotropy of the material and the thickness of the test specimen.

6 Apparatus

Placing a mirror in the chamber to provide a rear view of the test specimen has been

found to be useful.

The air-circulating oven shall provide a conditioning temperature of 70 °C +/- 2 °C,

unless otherwise stated in the relevant specification, whilst providing not less than five

air changes per hour.

7 Test specimens

Other measuring devices equivalent to a micrometer may be used to measure thickness

if found to be satisfactory.

Test specimens with extremes of density, melt flows and filler/reinforcement content

may be provided and considered representative of the range if the test results yield the

same flame test classification. If the test results do not yield the same flame test

8 Test method A - Horizontal burning test

Three test specimens shall be tested. Each test specimen shall be marked with two lines

perpendicular to the longitudinal axis of the bar, 25 mm +/- 1 mm and 100 mm +/- 1 mm

from the end that is to be exposed to the test flame.

With the central axis of the burner tube vertical, place the burner remote from the test

specimen and set the burner (see 6.2) to produce a standardized 50 W nominal test flame,

conforming with GB/T 5169.22-2015.The flame shall be confirmed.

9 Test method B - Vertical burning test

Clamp the test specimen using the upper 6 mm of its length with the longitudinal axis

vertical. The lower end of the test specimen shall be 300 mm +/- 10 mm above the

horizontal cotton pad (see 6.12). The cotton pad shall be approximately 50 mm x 50

mm x 6 mm (uncompressed thickness) and shall have a maximum mass of 0.08 g (see

Figure 3).

Maintaining the central axis of the burner tube in the vertical position, approach the test

specimen horizontally towards the wide face (see Figure 7).

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