iec 60335-1 cap3-2,.pdf

IEC 60335-1 (Ed. 4.2) Household and similar electrical appliances -

Safety -

Part 1: General requirements

Fire hazard assessment according to sub-clause 30.2

TC 61

Which standard is used ?

Test standard used is:IEC 60695-2-11 Fire Hazard Testing

Part 2.11: Glowing/hot wire based test methods

Glow-wire flammability test method for end products

TC 61

Important definitions

Some definitions from IEC 60695-2-11 are:

(te) being the duration from the beginning of tip application up to the time when flames extinguish during or after the period of application;

(ti) being the duration from the beginning of tip application up to the time at which the test specimen or the specified layer placed below it ignites;

In accordance with clause 11 of IEC 60695-2-11 both te and ti must be reported when detailing the results of the glow-

wire test performed

TC 61

Risk Assessment

For appliances, the glow-wire test severity is selected according to the risk presented by a given type of appliance. The risk is assessed based on three criteria

Whether the appliance is attended or unattended during normal use;

The rms value of current passing through an electrical

connection during normal use;

The proximity of non-metallic material to such

connections.

TC 61

Selection of Test Severity

For all appliances and regardless of current a minimum severity of 550

C is specified as being applicable to non-metallic material.

For attended appliances the break point current is 0,5 A for testing non-metallic material in proximity to a connection

Severity is 750

C if the current > 0,5 A Severity is 650

C if the current

0,5 A

For unattended appliances the break point current is 0,2 A for testing non-metallic material in proximity to a connection

Severity is 850

C and 750

C if the current > 0,2 A Severity is 650

C if the current

0,2 A

TC 61

Pass/Failure Criteria

There are two pass/failure criteria for the glow-wire test these are:

1. The value of te shall not exceed 60 s;2. The layer below shall not ignite.

In order to fulfill the requirements of IEC 6695-2-11 and IEC 60335-1 both criteria must be met for the severity levels applied

TC 61

Consequential Testing

For unattended appliances, the reported results of the 750

C and 650

C glow-wire tests related to the test specimen (not

the layer below) are used to decide whether further fire hazard tests are necessary in accordance with the penultimate paragraph of clause 4 in IEC 60695-2-11 that states:

If the test specimen emits flames during the application of the glow-wire, the fire hazard created may necessitate further tests using other ignition sources such as the needle-

flame applied to those parts which are reached by the emitted flames.

The rationale for this additional assessment is given in an informative note in 89/389/RM

TC 61

Criteria for applying the Consequential Test

In order to aid with repeatability and reproducibility the consequential needle flame is applied to non-metallic material that falls within a 20 mm x 50 mm (diameter x height) hypothetical cylinder placed above the connection being investigated and only in instances where (te

ti) > 2s.

Some time line diagrams that explain the glow-wire test methodology that may lead to a consequential test follow.

TC 61

Time LinesGlow-wire tip removed 30 s

Compliance boundary 60 s

Glow-wire tip applied 0 s

Test No

TC 61




Test No

Glow-wire tip removed 30 s



Test No

1No Ignitiont e - t I = 0 s

Pass and no consequential assessment necessary

since t e - t I = 0 s

TC 61




Test No




Test No




2


since t e - t i

2 s

t i t e

Ignition but 0 s < t e - t i

2 s

TC 61




Test No




Test No




2


since t e - t i

2 s

t i t e


2 s

3


since t e - t i

2 s

t i t e


2 s

TC 61




Test No




Test No




2


since t e - t i

2 s

t i t e


2 s

3


since t e - t i

2 s

t i t e


2 s

4


since t e - t i

2 s

t i t e


2 s

TC 61




Test No

5

Pass but consequential assessment necessary

since t e - t i > 2 sIgnition

t et i




Test No

TC 61




Test No

7

6



t et i

5



t et i




Test No

TC 61




Test No

7



t et i

6



t et i

5



t et i




Test No

TC 61




Test No

8

Ignition

t e


since t e - t i > 2 s

t i

7



t et i

6



t et i

5



t et i




Test No

TC 61




Test No

9

t e



t i

8

Ignition

t e



t i

7



t et i

6



t et i

5



t et i




Test No

TC 61




Test No

t et i

Fail sincet e > 60 s

10

Ignition




Test No

TC 61




Test No

t et i


11

Ignition

t et i


10

Ignition




Test No

TC 61




Test No

t et I


12

Ignition

t et i


11

Ignition

t et i


10

Ignition




Test No

TC 61

Small Parts

According to IEC 60695-2-11 clause 4 last paragraph:

The glow-wire test shall not be used for small parts for which reference may need to be made to other test methods, for example, the needle-flame test in IEC 60695-11-5.

In the fifth edition of IEC 60335-1 that is under preparation, it is proposed to apply this requirement to small parts even in attended appliances. However in general, if the small part is an isolated insignificant part in that it weighs less than 0.5 g

then it will be exempt.

TC 61

Small Parts Defined

A small part is a part, where each surface lies completely within a circle of 15 mm diameter (part is too small to grip and at the same time apply the GW tip

see example A), or

parts, where some of the surface lies outside a 15 mm diameter circle but in such a way that it is not possible to fit

a

circle of 8 mm diameter on any of the surfaces (part is large enough to grip but is too small to apply the GW tip

see

example B)

TC 61

Schematic Representation of a Small Part

Example A of a small part

Surface

Example B of a small part

Surface

Surface

Example of a part that is not a small part

Circles are 8 mm and 15 mm in diameter

TC 61

Pre-selection Procedure

Guidance given in IEC 60695-1-30 states:

It should be noted that when preselection testing is used to replace some of the end product testing, it is necessary to have a level of performance corresponding to an increased margin of safety in an attempt to ensure satisfactory performance of the end product.

TC 61

Pre-selection Alternatives for the Glow-wire Test

IEC 60695-2-11 Glow-wire test: Pre-selection alternatives are: 1.

IEC 60695-2-12, Glow-wire flammability index (severities selected from 550 C, 650 C, 750 C or 850 C depending on the glow-wire test severity specified in IEC 60335-1)

2.

IEC 60695-2-13, Glow-wire ignition temperature (severities selected from 675 C or 775 C depending on the glow-wire test severity specified in IEC 60335-1 for the consequential test decision for unattended appliances)

3.

IEC 60695-11-10, 50 W Flame tests (HB40 for the 550 C glow-wire test ).

TC 61

Pre-selection Alternatives for the Needle Flame Test

IEC 60695-11-5 Needle Flame test: Pre-selection alternative is:

IEC 60695-11-10, 50 W Flame Tests (at least V-1).

TC 61

Options to Avoid the Consequential Test

1.

Use the glow-wire ignition temperature pre-selection option;

2.

Use the 50 W flame test pre-selection option;3.

Use of flame barriers;

4.

Appropriate placement with respect to the 20 mm x 50 mm cylinder.

TC 61

Which Option to Choose

The choice of option is not specified in IEC 60335-1

The choice is strictly a commercial decision to be made by the appliance manufacturer and this aligns with the opinion of ACOS as stated in ACOS/420/RM item 8.1.2

TC 61

TO ENSURE CORRECT APPLICATION OF THE REQUIREMENT AND TEST SPECIFICATION IN SUB-CLAUSE 30.2 OF

IEC 60335-1 READ AND APPLY THE DETAILED TEXT FROM THE STANDARD

THANK YOU

TC 61

- 1 -

TC 61 SAFETY OF HOUSEHOLD AND

SIMILAR ELECTRICAL APPLIANCES

Fire hazard assessment according to 60335-1 Clause 30.2 1) The standard (IEC 60335-1) uses the end product glow-wire tests of IEC 60695-2-11 to assess the fire hazard presented by a given appliance design. If the value of te obtained during the tests of IEC 60695-2-11 exceeds 60 s, this indicates a non-compliance with IEC 60695-2-11 and a hence a failure of the standard (IEC 60335-1) Clause 30.2 requirements. Note that te is defined in IEC 60695-2-11 and according to clause 11 of IEC 60695-2-11 the value must be reported when detailing the results of the tests.

(te) is the duration from the beginning of tip application up to the time when flames extinguish during or after the period of application;

2) The glow-wire test severities are selected from 550 oC, 650 oC, 750 oC or 850 oC depending on the risk presented by a given appliance. The risk presented by a given appliance is assessed according to whether the appliance is attended or unattended during normal use, the rms level of current through a connection during normal operation and the proximity of non-metallic material to such connections. In all cases a minimum severity of 550 oC is specified in order to prohibit the use of fiercely burning non-metallic material. 3) For appliances that operate unattended, the standard (IEC 60335-1) applies a consequential needle flame test (IEC 60695-11-5) to other non-metallic parts in accordance with IEC 60695-2-11 Clause 4 penultimate paragraph, in cases where the flame from the glow-wire test (severity 750 oC or 650 oC as appropriate) may impinge upon these non-metallic parts and the value of (te - ti ) exceeds 2 s. IEC 60695-2-11 Clause 4 penultimate paragraph states:

If the test specimen emits flames during the application of the glow-wire, the fire hazard created may necessitate further tests using other ignition sources such as the needle-flame applied to those parts which are reached by the emitted flames.

The value of 2 s is the value below which sporadic flames can be ignored and was selected in order to aid reproducibility and repeatability. IEC 60695-2-11 does not define ignition, nor does ISO/IEC 13943, Fire safety Vocabulary, which is referenced in IEC 60695-2-11. Note that ti is defined in IEC 60695-2-11 and according to clause 11 of IEC 60695-2-11 the value must be reported when detailing the results of the tests.

(ti) is the duration from the beginning of tip application up to the time at which the test specimen or the specified layer placed below it ignites;

Some time line examples of the IEC 60335-1 application of the consequential test requirements in 60695-2-11 are give in Figure A.

- 2 -

FIGURE A - Some time lines for the Glow-wire test according to IEC 60695-2-11 as

applied in IEC 60335-1 clause 30.2 for unattended appliances

2

1

3

Ignition

t i t e

t i t e

Ignition but 0 s < t e - t i 2 s

No Ignition t e - t I = 0 s


since t e - t i 2 s






Test No Pass and no consequential assessment necessary


t e t i


4

Ignition

- 3 -

The rationale for the consequential tests specified by TC 89 is given in the informative note to 89/389/RM. This is as follows:

- 4 -

4) For unattended appliances, the standard (IEC 60335-1) states that for parts that are too small to apply the glow-wire test from IEC 60695-2-11, then for these parts the needle flame test (IEC 60695-11-5 formerly IEC 60695-2-2) is applied in accordance with IEC 60695-2-11 Clause 4 last paragraph. This states

The glow-wire test shall not be used for small parts for which reference may need to be made to other test methods, for example, the needle-flame test in IEC 60695-2-2.

It is proposed to extend the small parts requirement to also apply in the case of attended appliances. However, in all appliances isolated insignificant parts being those that weigh less than 0.5 g will be exempt. 5) Following the definition of a small part in IEC 60695-2-11, it is proposed that the standard (IEC 60335-1) will define a small part as a part, where each surface lies completely within a circle of 15 mm diameter (part is too small to grip and at the same time apply the GW tip see example A), or parts, where some of the surface lies outside a 15 mm diameter circle but in such a way that it is not possible to fit a circle of 8 mm diameter on any of the surfaces (part is large enough to grip but is too small to apply the GW tip see example B)

6) At all stages throughout the assessment to Clause 30.2 of IEC 60335-1, pre-selection alternatives are allowed. These pre-selection alternatives are 7) For IEC 60695-2-11: Pre-selection alternatives are

(a) IEC 60695-2-12 Glow wire flammability index: (severities selected from 550 oC, 650 oC, 750 oC or 850 oC depending on the value specified in IEC 60335-1 for the IEC 60695-2-11 end product test) (b) IEC 60695-2-13 Glow wire ignition temperature: (severities selected from 675 oC or 775 oC depending on the value specified in IEC 60335-1 for the IEC 60695-2-11 end product consequential test decision for unattended appliances)

Example A of a small part

Surface

Example B of a small part

Surface

Surface

Example of a part that is not a small part

Circles are 8 mm and 15 mm in diameter

- 5 -

(c) IEC 60695-11-10 50 W flame tests: (HB40 for the 550 oC IEC 60695-2-11 end product test). This alternative applies to the general requirement for non-metallic material that has historically been included to prohibit the use of fiercely burning non-metallic material. It only requires the material to be slow burning rather than self extinguishing.

8) For IEC 60695-11-5 Needle flame test: Pre-selection alternative is IEC 60695-11-10 50 W flame tests: (at least V-1). 9) The preselection alternative severities are completely compatible with the guidance given in IEC 60695-1-30 Ed 1.0 clause 5.2 (a) - see text below.

It should be noted that when preselection testing is used to replace some of the end product testing, it is necessary to have a level of performance corresponding to an increased margin of safety in an attempt to ensure satisfactory performance of the end product.

(Equivalent text is included in the second sentence of the second paragraph of clause 5 item (c) in 89/865/FDIS which will form the basis of IEC 60695-1-30 Ed 2.0 ). 10) In order to avoid a consequential needle flame test in unattended appliances as per item 3) above, the appliance manufacturer may

(a) use components that comply with the 750 oC or 650 oC, as appropriate, glow-wire test with a value of (te - ti) not exceeding 2 s or its pre-selection alternative (GWIT of 775 oC or 675 oC as appropriate); or (b) ensure that non-metallic parts surrounding a component and that fall within a hypothetical cylinder 20 mm diameter and 50 mm high comply with the needle flame test or its pre-selection alternative (at least V-1); or (c) place a component in such a way that there are no non-metallic parts surrounding the component and that fall within a hypothetical cylinder 20 mm diameter and 50 mm high.

11) In order to avoid a consequential needle flame test being applied to a component used in unattended appliances as per item 3) above, even in cases where the component complies with its own standard fire hazard requirements, the appliance manufacturer may

(a) use components that comply with the needle flame test or its pre-selection alternative (at least V-1); or (b) shield the component by use of flame barrier in such a way that if its non-metallic parts fall within a hypothetical cylinder 20 mm diameter and 50 mm high placed near connections within the appliance. The flame barrier is made of material that complies with the needle flame test or its pre-selection alternative (at least V-1); (c) place the component in such a way that its non-metallic parts do not fall within a hypothetical cylinder 20 mm diameter and 50 mm high placed near connections within the appliance.

- 6 -

12) The manufacturers choice for items 10) and 11) is strictly a commercial decision to be made by the appliance manufacturer and this aligns with the opinion of ACOS in ACOS/420/RM item 8.1.2 that states:

Conclusion 0605/17 TC 61 assessment of appliances for resistance to fire

The specification of components with the correct resistance to fire characteristics is considered to be the responsibility of the appliance manufacturer and of a purely commercial nature and consequently does not fall within the scope of ACOS.

CONCLUSIONS: 1) The standard (IEC 60335-1) requires that generally all non-metallic material shall have a specified level of self extinguishing properties. In particular, it also requires that non-metallic material that supports current carrying connects (meaning is in contact with current carrying connections) or is within 3 mm of current carrying connections to have a specified level of self extinguishing properties that is above the general requirement.

NOTE: The contribution to the fire hazard presented by an appliance due to over-heating components is covered by the tests in Clause 19 of IEC 60335-1.

2) Since the application of the consequential test requirement has been applied in Europe by alignment of Clause 30.2 in EN 60335-1 with Clause 30.2 in IEC 60335-1, the appliance fire statistics reported to TC 61 from Europe have shown a sharp reduction in property damage due to fires resulting from bad connections in appliances. Note that consequential testing has been applied at IEC level since 1984 but at CENELEC level only since 2003. 3) End product standards that refer to components incorporated in the end product do not allow the component standard to set the safety requirements for the end product (see for example IEC 60335-1 clause 24.1 and IEC 61010 clause 14.1 and Figure 10) otherwise the lowest common denominator would apply. This generally applies to parameters such endurance, creepage distances and clearances, fire hazard levels, T-ratings, etc. 4) A complete flow chart for IEC 60335-1 clause 30.2 (current and proposed in 61/3513a/CD) is attached. However irrespective of the flow chart and summary given in items 1) to 12) above, reference must be made to the text in IEC 60335-1 clause 30.2 for complete details and application of the methodology.

- 7 -

Surrounding parts to be at least V-1

Glow-wire withstand with

ignition

Glow-wire withstand without

ignition

Needle-flame test on surrounding parts

For connections carrying 0,2 A in

unattended appliances

For connections carrying >0,2 A in unattended

appliances

Material to have a GWIT of

at least 775 C

Glow-wire test

at 750 C

Glow-wire test

at 650 C

Material to have a GWIT of

at least 675 C

Material to have a GWFI of

at least 850 oC

Glow-wire test

at 850 oC

Material to be at least V-0

PCB base material with > low-power

circuits in other than hand-held

and similar appliances

Needle-flame test

Decorative trims,

knobs, etc.

No tests


at least 650 oC

Glow-wire withstand

For connections carrying >0,5 A

in attended appliances

Glow-wire test

at 750 C Material

to be HB40 or HBF

as appropriate

Other parts in attended and unattended

appliances and all parts of hand-held

and similar appliances

Glow-wire test

at 550 C

For connections carrying 0,5 A

in attended appliances

Glow-wire test

at 650 C


at least 750 oC

IEC 627/06

Flow chart for clause 30.2, IEC 60335-1 Ed 4.2

Note: With reference to connections, the GWT, GWIT and GWFI requirements are applied to material in contact with or within 3 mm of connection carrying current of the values specified.

- 8 -

Note: With reference to connections, the GWT, GWIT and GWFI and small parts requirements are applied to material in contact with or within 3 mm of connection carrying current of the values specified.

PCB base material with > low-power

circuits in other than hand-held and similar appliances

Material to be at least V-0 or

VTM-0

Needle-flame test

Decorative trims,

knobs, etc.

No tests

Glow-wire test at 850 C

Material to have a GWFI of at

least 850 C

For connections carrying 0,2 A and parts within

3 mm in unattended appliances

Small parts, NFT or to be at

least V-1

Surrounding parts to be at least V-1

NFT on surrounding parts

Material to have a GWIT of at least 775 C

Glow-wire withstand with

ignition

Glow-wire withstand

without ignition



Material to have a GWIT of at least 675 C

Small parts, NFT or to be at

least V-1

Small parts, NFT or to be at least

V-1

For connections carrying >0,2 A and parts within

3 mm in unattended appliances

Other parts in attended and unattended

appliances and all parts of hand-held and similar

appliances

Material to have a GWFI of at

least 550 C

Material to be HB40 or HBF

as appropriate


For connections carrying 0,5 A and parts within

3 mm in attended appliances

For connections carrying >0,5 A and parts within 3 mm in attended appliances

Material to have a GWFI

of at least 750 C

Material to have a GWFI

of at least 650 C



Glow-wire withstand

Small parts, NFT or to be at least V-1

Small parts, NFT or to be at least V-1

Proposed flow chart for clause 30.2 IEC 60335-1 Ed 5

IEC 60335-1 (Ed. 4.2)Household and similar electrical appliances - Safety -Part 1: General requirementsWhich standard is used ?Important definitionsRisk AssessmentSelection of Test SeverityPass/Failure CriteriaConsequential TestingCriteria for applying the Consequential TestFoliennummer 9Foliennummer 10Foliennummer 11Foliennummer 12Foliennummer 13Foliennummer 14Foliennummer 15Foliennummer 16Foliennummer 17Foliennummer 18Foliennummer 19Foliennummer 20Foliennummer 21Foliennummer 22Foliennummer 23Foliennummer 24Foliennummer 25Foliennummer 26Foliennummer 27Foliennummer 28Foliennummer 29Foliennummer 30

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