GB 4706.XX-XXXX ICS 13.120 K09

National Standard for the People’s Republic of China

GB 4706.XX-XXXX

Safety of Household and Similar Electrical Appliances Particular Requirements for Thermal-Storage Hand Warmers

(Draft for approval) Released on ××/××/×××× Implemented on ××/××/××××

Issued by

General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China

Standardization Administration of the People’s Republic of China

GB 4706.XX-XXXX

Table of Contents Introduction.......................................................................................................................................... 3 1. Scope .......................................................................................................................................... 4 2. Normative reference....................................................................................................................4 3. Terms and definitions ..................................................................................................................4 4. General requirements .................................................................................................................5 5. General conditions of tests ......................................................................................................... 5 6. Classification...............................................................................................................................5 7. Marking and instructions.............................................................................................................5 8. Protection against access to live parts .......................................................................................6 9. Starting of motor-operated appliances........................................................................................6 10. Power input and current.......................................................................................................... 6 11. Heating.................................................................................................................................... 6 Table 101 Max. normal temperature rise ............................................................................................7 12. Void ......................................................................................................................................... 7 13. Leakage current and electric strength at operating temperature........................................... 7 14. Transient overvoltage..............................................................................................................7 15. Moisture resistance.................................................................................................................7 16. Leakage current and electric strength ....................................................................................7 17. Overload protection of transformers and associated circuits .................................................7 18. Endurance...............................................................................................................................7 19. Abnormal operation.................................................................................................................7 20. Stability and mechanical hazards ...........................................................................................8 21. Mechanical strength................................................................................................................8 22. Construction............................................................................................................................9 23. Internal wiring..........................................................................................................................9 24. Components............................................................................................................................9 25. Supply connection and external flexible cords ....................................................................... 9 26. Terminals for external conductors...........................................................................................9 27. Provision for earthing..............................................................................................................9 28. Screws and connections....................................................................................................... 10 29. Clearances, creepage distances and solid insulation ..........................................................10 30. Resistance to heat and fire................................................................................................... 10 31. Resistance to rust ................................................................................................................. 11 32. Radiation, toxicity and similar hazards ................................................................................. 11 Figure 101 Symbol indicating “no pin inserted”.................................................................................12 Figure 102 the shape of sample for tear resistance test................................................................... 12 Figure 103 Device for sparkle ignition test........................................................................................13 Figure 103a Template details ............................................................................................................ 14 Annex.................................................................................................................................................15 Annex AA (Normative annex) Testing device for mechanical strength .............................................15 Figure AA.1 Testing device for mechanical strength of outer casing materials................................16 Figure AA.2 details of roller and cylinder...........................................................................................17 Figure AA.3 details of clamp lever..................................................................................................... 17 Bibliography....................................................................................................................................... 18

GB 4706.XX-XXXX

Introduction All technical content in this document is mandatory. GB4706 means a series of standards on the safety of household and similar electrical appliances, and it is divided into two parts: The first part: general requirements; The second part: particular requirements. This document constitutes the second part of GB4706. This document includes particular requirements on the safety of household and similar thermal storage hand warmers; and it shall be used with GB 4706.1-2005, General Requirements, Part 1, Safety of Household and Similar Electrical Appliances. This document is shaped by supplements, additions or amendments to GB 4706.1; The part indicated with “Applicable” means that the corresponding provisions in GB 4706.1 also apply to this document; the part indicated with “Replacement” means the provisions in this document prevail; the part indicated with “Amendment” means the related content of corresponding provisions in GB 4706.1 is subject to the amendments in this document, and the remaining content of the said provisions is still applicable; and the part indicated with “Addition” means that the supplemented provisions shall be applied besides the corresponding provisions in GB 4706.1. The additions to GB 4706.1 start from No.101. This document is proposed by the China National Light Industry Council. This document is under the jurisdiction of the National Household Appliance Standardization Technical Committee (SAC/TC46). The organizations that participated in the drafting of this document are: Guangzhou Electric Apparatus Research Institute, Chengdu Rainbow Electric (Group) Co., Ltd., Guangdong Midea Group Co., Ltd., Foshan Shunde Kebei Intelligent Electric Co., Ltd., Guangdong Shunde Entry-Exit Inspection And Quarantine Bureau and Guangzhou Vkan Certification & Testing Institute. The drafters of this document are: Xu Yanrong, Liu Xiangdong, Li Zhengyong, Chen Lushi, Li Dening, Lu Dongqi and Zeng Wenli. This standard was issued for the first time..

GB 4706.XX-XXXX

Safety of Household and Similar Electrical Appliances Particular requirements for thermal-storage hand warmers

1. Scope This chapter in GB 4706.1-2005 is replaced by the following content: This document applies to the safety of household and similar purpose thermal-storage hand warmers with the rated voltage not exceeding 250 V (hereinafter referred to as “Hand warmer”) and similar apparatus. This document is also applicable to the control device supplied with apparatus. The common hazards that exist when operating the apparatus mentioned in this document may be encountered by every person in or around the house. However, this document generally does not cover the following:

——hazards arising from the use of apparatus by unattended infants or the handicapped.

——situations where infants play with apparatus.

Note 101: Unattended children cannot use the apparatus until they get correct guidance from their parents or guardians and are considered to be qualified to use it. Note 102: The following conditions need attention: •• Additional requirements may be required for apparatus intended for use in vehicles, ships or aircrafts. •• In many countries, additional requirements have been stipulated for apparatus by the national healthcare departments, national labor protection departments and similar departments; Note 103: This document does not apply to the following: ••apparatus intended for use in the special environment where corrosive or explosive gases (for example, dust, steam or gas) are often generated; •• electric blankets, electric warming pads and similar soft heating apparatus (GB 4706.8); •• indoor heaters(GB 4706.23); •• water bed heaters(GB 4706.58); •• electric heaters intended for breeding and rearing animals (GB 4706.47); •• electric foot warmers and heating mats (GB 4706.80); •• non thermal storage hand warmers; •• professional apparatus used by patients getting medical care (IEC 60601-2-35).

2. Normative reference This chapter in GB 4706.1-2005 is applicable.

3. Terms and definitions The following terms and definitions are applicable to this document: All provisions of this charter in GB 4706.1-2005, except for the following content, are applicable.

3.1.9 Replacement:

Normal operation The apparatus operates under the following conditions:

Place a hand warmer horizontally or according to the instructions provided. Connect it to power supply. The thermal storage process will end when the device which controls the temperature of the thermal storage kernel cuts off the power supply for all electric heating components for the first time.

GB 4706.XX-XXXX

3.101 Hand warmer An apparatus which is held by the user to warm his/her hands by converting electricity to heat. 3.102 Thermal storage hand warmer A hand warmer which stores the heat converted from electricity in a kernel and releases heat in a natural way. This kind of hand warmer is disconnected with the power supply when it is held by the user to warm his/her hands. 3.103 Hard hand warmer A hand warmer with the hard outer casing. 3.104 Soft hand warmer A hand warmer with the soft outer casing.

4. General requirements This chapter in GB 4706.1-2005 is applicable.

5. General conditions of tests All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: 5.2 Addition:

According to test requirements, add more samples required by the test.

Add one sample for conducting the test in 21.101. For soft hand warmers, the outer casing material with the dimensions of 1 200 mm×1 200 mm is required to conduct the tests in 21.102, 21.103 and 30.101.

5.3 Addition:

For soft hand warmers, the test in 21.104 shall be conducted after the test in Chapter 29.

5.5 Addition: If an apparatus has a removable envelope, the test shall be conducted under the conditions with or without envelope, whichever is unfavorable. If an apparatus is required to use with envelope according to the instructions provided, the test shall be done with envelope. If the electric heating components are removable, they shall be moved to the most unfavorable positions for the test. 5.7 Amendment: The environment temperature of tests is 23• ±2•.

6. Classification All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable. 6.1 Amendment: The apparatus shall belong to the type II or III category. The rated voltage of Type III apparatus shall not exceed 24V.

7. Marking and instructions

All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable:

7.1 Amendment: The apparatus shall be marked with the rated power input. Addition: The apparatus shall be marked with the following:

GB 4706.XX-XXXX

—— No service is allowed when the apparatus is live.

Hard hand warmers shall be marked with the following: —— the symbol indicating “Do not cover” or the graphical symbol IEC60417-5641(DB•2002-10). Soft hand warmers shall be marked with the following: —— the symbol indicating “No pin inserted” or the symbol indicated in Figure 101. 7.12 Addition: The instructions shall contain the following: Important: Keep it in a safe place for future use; it can not be used by dependent people, infants or people insensitive to heat. The instructions shall contain the following: —— The apparatus shall be used with the supporting connector; —— If the apparatus is marked with the symbol indicating “Do not cover”, its meaning shall be explained as follows; —— Place the apparatus out of children’s reach when it is connected to the mains for thermal preservation. —— Leave the apparatus to cool down to room temperature before storing it. —— Do not place any objects on the apparatus when it is being connected to the mains or during storage. —— Check the apparatus for any signs of abrasion or damage from time to time; in case of such signs, please do not use it. The instructions of soft hand warmers shall contain the following: —— Do not flush it with water; —— Do not touch sharp or pointed objects; —— Prevent it from falling on the ground and do not put a heavy load on it; —— Do not wipe it with gasoline, toluene or other strong solvents. The instructions shall specify that the apparatus is not suitable for use by children unless their parents or guardians have set it beforehand, or have informed children of the usage in detail. 7.14 Addition: The height of Figure 101 and the graphic symbol of “Do not cover” shall be 15 mm at least. The font height of “Important” and its content shall be 6 mm at least. Conformity is subject to measurement.

8. Protection against access to live parts This chapter in GB 4706.1-2005 is applicable.

9. Starting of motor-operated appliances This chapter in GB 4706.1-2005 is not applicable.

10. Power input and current This chapter in GB 4706.1-2005 is applicable.

11. Heating All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: 11.2 Amendment:

Put a hand warmer at the test corner under normal operation conditions, with it being close to one side wall and away from the other.

11.8 Addition: The temperature rise of the surface of hand warmer, the wall of the test corner and the base

GB 4706.XX-XXXX

plate shall not exceed the value indicated in Table 101.

Table 101 Max. normal temperature rise Surface

Temperature rise

K Surface of hand warmer 75

Wall of test corner and base plate 7

12. Void

13. Leakage current and electric strength at operating temperature This chapter in GB 4706.1-2005 is applicable.

14. Transient overvoltage This chapter in GB 4706.1-2005 is applicable.

15. Moisture resistance This chapter in GB 4706.1-2005 is applicable.

16. Leakage current and electric strength

This chapter in GB 4706.1-2005 is applicable.

17. Overload protection of transformers and associated circuits This chapter in GB 4706.1-2005 is applicable.

18. Endurance This chapter in GB 4706.1-2005 is not applicable.

19. Abnormal operation All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: 19.2 Addition:

Put a hand warmer at the test corner under normal operation conditions, with it being close to one side wall and away from the other. Place one piece of heat insulation material which is 36 mm thickness under the hand warmer as a pad, and cover the hand warmer completely or partly with another piece of heat insulation material with the same thickness, whichever is unfavorable.

For those soft hand warmers that require users to add liquid by themselves, test them with a full load or no load, whichever is unfavorable. The heat insulation material comprises the following content:

Apertured polyether;

Aperture number: 18 /cm;

Specified mass: 30kg/m3

%; Hardness: 120N - 170N at 40% of the impress measured in line with GB/T 10807(idt ISO 2493).

19.13 Addition: During test period, the temperature rise of the hand warmer surface contacting heat insulation

GB 4706.XX-XXXX

material shall not exceed 155K.

20. Stability and mechanical hazards This chapter in GB 4706.1-2005 is applicable.

21. Mechanical strength All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: 21.1 Addition:

Hand warmers are also required to withstand the test in 21.101.

Soft hand warmers are also required to withstand the tests in 21.102, 21.103 and 21.104. After such tests, the apparatus shall be free of the following:

—— damage of the outer casing which may lead to nonconformity with the requirements in this document;

—— breakage of electric heating components; —— damage of structure joint, or breakage of adhesion or welding points which may lead to nonconformity with the requirements in this document; —— detachment of input socket of apparatus; —— disconnection or breakage of electric connection. Addition: 21.101 Take a hand warmer, position it downwards at the most unfavorable position, and allow it to fall freely from the height of 900 mm to a fixed horizontal hardwood board with thickness of about 20 mm. Conduct this test 3 times. The flexible power cord of the hand warmer shall be removed from the input socket of the apparatus, because the cord is not within the scope of this test. After this test, the hand warmer shall be free of such damages which may lead to nonconformity with the requirements of this document. If the hand warmer can still continue to operate, it shall be subject to the test in Chapter 11. 21.102 For soft hand warmers, attach the outer casing material of 1 000 mm×1 000 mm tightly to the device described in Annex AA. The outer casing material is pulled by a drive bar and the drive gear works at the speed of 33 cycles / min. Attach one end of the outer casing material to the drive bar for 1000-cycle rotation, and then rotate it 90º for another 1000-cycle rotation. Note: this test is conducted under the condition where the roller is close to the same surface with the outer casing material. 21.103 The outer casing material for soft hand warmers shall provide good tear resistance under normal operation conditions. Conformity is subject to the following test. Put five samples of outer casing material as indicated in Figure 102 under the environment where temperature is 23•±2•. Fix the short side of each sample completely on the clamps of a stretching machine, with the sample and clamp on the same plane. Make the clamps take apart at the speed of 50 mm/min until the sample is torn up, and measure the max. breaking load. The average value of breaking load for five samples shall not be less than 12.5 N. 21.104 Soft hand warmers shall withstand the crushing test. Conformity is subject to the following test. Support a hand warmer completely with a piece of plywood with a thickness of about 20 mm, place a piece of plywood of 300 mm×300 mm×20 mm on the top surface of the hand warmer at the most unfavorable position, and place a weight of 80 kg on the plywood for 5 min. After the test, the hand warmer shall have no leakage of liquid or breakage. Note: the edges of the plywood shall be round and smooth.

GB 4706.XX-XXXX

22. Construction All provisions of this charter in GB 4706.1-2005, except for the following content, are applicable. 22.7 Amendment: In terms of structure, soft hand warmers shall be equipped with the protection device which can prevent over-high pressure inside the warmer during it is connected to the mains. Through the visual inspection, if the apparatus is installed without such over-high pressure protection device, the apparatus is identified as failure to meet the requirement; if that device is available, conformity will be subject to the following test: Under the conditions specified in Chapter 11, a hand warmer is input the power that is 1.15 times of the rated power input.

All thermal controllers shall occur short circuit at the same time.

Leave the hand warmer operate until the over-high pressure protection device works. After the test, the hand warmer shall have no leakage of liquid or breakage. Addition: 22.101 The structure of hand warmer shall hold the electric heating components and internal wiring at their pre-configured positions. Conformity is subject to the visual inspection. 22.102 For soft hand warmers, except for Type III apparatus, the insulation of electric heating components and internal wiring shall be integrated with conductors. Conformity is subject to the visual inspection. 22.103 No burrs that may damage soft materials shall exist in the internal structure or at connection terminal of the soft hand warmer. Conformity is subject to the visual inspection.

23. Internal wiring This chapter in GB 4706.1-2005 is applicable.

24. Components All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: Addition:

24.1.4 Amendment:

The working cycle-times of the self-resetting thermal cut-out is 10,000. 24.101 For soft hand warmers, at least one thermal cut-out which limits the temperature of thermal storage kernel is of a non self-resetting type.

Conformity is subject to the visual inspection.

25. Supply connection and external flexible cords This chapter in GB 4706.1-2005 is applicable.

26. Terminals for external conductors This chapter in GB 4706.1-2005 is applicable.

27. Provision for earthing

This chapter in GB 4706.1-2005 is not applicable.

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28. Screws and connections

This chapter in GB 4706.1-2005 is applicable.

29. Clearances, creepage distances and solid insulation

This chapter in GB 4706.1-2005 is applicable.

30. Resistance to heat and fire All provisions of this chapter in GB 4706.1-2005, except for the following content, are applicable: 30.1 Addition:

This requirement is not applicable to soft hand warmers.

30.2 Addition: This requirement is not applicable to soft hand warmers.

Addition:

30.101 Soft material shall have flame resistance. Conformity is subject to the following spark ignition test. Cut off six samples from the outer casing material, making each with the dimensions of 100 mm×200 mm, and no two samples appear on the same longitude or latitude line. If it fails, no more than two samples appear on the same line when samples are selected. If the outer casing material is inseparable, use the double layer material for testing. The test device, as shown in Figure 103, has two copper electrodes with a diameter of 3 mm, which are installed on an insulated base plate through two copper rods, making their axes align each other. On the base plate, there also stands a platform with the dimensions of 100 mm×100 mm which is made of insulation material. This platform is found between the two copper rods and equipped with a mechanism designed to adjust the platform height. Fix one electrode and leave the other removable, so that the sample can be inserted. The fixed electrode has an angle of 45o on its pointed end. The farthest point on the electrode away from the copper rod shall be on the pointed end of the electrode and its distance away from the platform shall be about 3 mm. The removable electrode has a flat end. Place the lower element of one piece of hardwood template, as shown in Details A of Figure 103a, at the specified position of the adjustable platform. Put the testing device, including the upper element of the template, as shown in Details B of Figure 103a, into a heating chamber, which has a door with an observation window, where natural convection circulation of air can be achieved. Make series connection of the electrode, and one adjustable non-inductive resistance, to a power supply with sinusoidal rated output voltage of 10kV. The power supply features that output voltage does not decrease by above 100V when the current flow is 1 mA. Raise the temperature of the heating chamber to 65•±2•. Then short circuit the electrode, and adjust resistance to contribute to 1 mA current flow. Disconnect the power supply, and leave the sample in the heating chamber for 3 hours. Do not take the testing device from the heating chamber. Take away the removable electrode, and pull one sample to the fixed electrode so that this electrode is at the centre of the space occupied by electric heating components. Adjust the sample to make one of its ends approximately parallel to the edge of the adjustable platform, and then insert the removable electrode into the other end of electric heating components, and get it fixed. The distance between two electrodes is 6.0 mm±0.1 mm. Make the sample level and position the upper element of the template. Close the door of the heating chamber for 5 minutes to stabilize the temperature. Then connect power supply and allow sparkle to exist between both electrodes for 2 minutes. If the sample is ignited, the time shall be recorded from the moment of power connection to when sparkle reaches the inner edge of the template. If the burning duration of the fibers on the surface does not last 3 seconds, it can be omitted. If the sample is not ignited, the time is

GB 4706.XX-XXXX

recorded as 120 seconds. After that, take out the sample and put the other side of the sample upwards between both electrodes, to make the opposite end experience the test. The test above is repeated for the other 5 samples. If any time record is less than 30 seconds, all tests are required to be repeated for a second group of 6 samples. Under such conditions, the time record of samples shall not less than 30 seconds. Calculate the average of 12 records. It should not be less than 80 seconds. Ignore all values where the difference with the average is greater than 30 seconds. If necessary, calculate the average of the remaining records again.

31. Resistance to rust This chapter in GB 4706.1-2005 is applicable.

32. Radiation, toxicity and similar hazards This chapter in GB 4706.1-2005 is applicable.

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Figure 101 Symbol indicating “no pin inserted”

Unit: mm

A: pull direction; B: striation direction.

Figure 102 the shape of sample for tear resistance test

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A: Adjustable platform; B: lower template (see Details A of Figure 103 a); C: fixed electrode; D: upper template(see Details B of Figure 103a); E: rod; F: removable electrode; G: base plate.

Figure 103 Device for sparkle ignition test

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Details A —— lower template

Details B —— upper template

Unit: mm Note: the mass of upper template is 100 g, which can be achieved by trimming its thickness.

Figure 103a Template details

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Annex

All provisions of the annex in GB 4706.1-2005, except for the following content, are applicable.

Annex AA (Normative annex) Testing device for mechanical strength

The testing device, as shown as Figure AA.1, features a rotating roller with a diameter of 160 mm, whose length is large enough to accommodate the total length of outer casing material. Cut open a solid rubber ball with the diameter of 60 mm±2.5 mm and Rockwell hardness of 40 – 50. Place them on the roller and make them protrude 25 mm above the roller. These semi-spheres are arranged in six rows evenly around the roller’s circumference, 320 mm apart from each other. Each semi-sphere is located at the middle position of a pair of semi-spheres of a neighbouring row (see Figure AA.2). This roller can rotate around its axis. Below the roller, there is a bar with square cross-section and side length of 25 mm×25 mm. It is constructed so that it can be installed on a guide rail and can rotate in the loader, which can move upwards or downwards freely. The total mass of the bar and loader can be adjusted by adding weights to the loader. There are some smooth hardwood cylinders with a diameter of 65 mm and a length of 140 mm above the roller, and each cylinder is fixed with a pair of arms. The cylinder arms are 160 mm away from the axis of the cylinder, around which the cylinder arms rotate. The position of these cylinders shall allow each semi-sphere to pass underneath the centre of a cylinder. The pivot bar is positioned so that the axis of the cylinder arms can form an angle of 25°to horizontal when the cylinders contact the top of the roller. The force applied on the roller by each cylinder is 5.1 N. A gear with a diameter of 230 mm is securely fixed at both ends of the supporting axis of the roller. A circular chain drives the drive bar around the gear, and goes through the lowest position of the bar with a square cross-section. Attach the clamp lever to the drive bar by using the screw with a diameter of 3.5 mm (as shown in Figure AA.3). On the edge of the clamp lever, there are steel swivels attached. Tightly connect the total length of the outer casing material to the steel wire swivels with clamps and an adjustable woven belt. Then let it pass around the roller, and go underneath the bar with square cross-section to be clamped with the other end of the woven belt. The outer casing material and woven belt form a continuous belt. It is pulled by adding weights to the loader, so that the total mass of the bar assembly and the loader enables the connection side of the outer casing material to bear the weight of 6 kg. Adjust the woven belt to increase by 50 mm from the non-operation position of the bar with the square cross-section and the loader, and then the pull force borne by the woven belt shall not be changed. The woven belt shall be positioned so that they can pass through between the semi-spheres on the roller.

Note 1: Sufficient woven belts shall be used to prevent wrinkles on the outer casing material.

Note 2: All flexible power cords and the connection types of the drive bar shall not affect the test results.

Note 3: A device shall be installed, which is designed to raise the cylinders when the drive bar passes through the roller, avoiding the damage of testing devices.

Note 4: Drive bars shall be driven separately. Both the roller and the bar with the square cross-section are driven to rotate by the outer casing material when it goes over them.

GB 4706.XX-XXXX

A: drive chain; B: clamp lever; C: drive bar; D: self-adjusting axis; E: locking cylinder; F: cylinder arm; G: gear; H: drive bar; I: bar with square cross-section; J: outer casing material in test

Figure AA.1 Testing device for mechanical strength of outer casing materials

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A: cylinders; B: cylinder arm; C: solid rubber ball.

Figure AA.2 details of roller and cylinder

Unit: mm A: steel pipe with the diameter of 25 mm and wall thickness of 1.6 mm; B: steel swivel with the diameter of 2.5 mm; C: hinge welded on the steel pipe.

Figure AA.3 details of clamp lever

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Bibliography

All provisions of the bibliography in GB 4706.1-2005, except for the following content, are applicable: Addition: GB 4706.8-XXXX (idt IEC 60335-2-17:2006) Safety of Household and Similar Electrical Appliances – Particular Requirements for Electric Blankets, Electric Warming Pads and Similar Soft Heating Apparatus GB 4706.23 (idt IEC 60335-2-30) Safety of Household and Similar Electrical Appliances – Particular Requirements for Indoor Heaters GB 4706.44 (idt IEC 60335-2-61) Safety of Household and Similar Electrical Appliances – Particular Requirements for Thermal-Storage Indoor Heaters GB4706.80 (idt IEC 60335-2-81) Safety of Household and Similar Electrical Appliances – Particular Requirements for Electric Foot Warmers and Heating Mats