Safety Glazing Materials in Building Part 2: Tempered Glass

Transcription

1 Translated English of Chinese Standard: GB Wayne Zheng et al. ICS Q 33 NATIONAL STANDARD GB OF THE PEOPLE S REPUBLIC OF CHINA GB Replacing GB 9963-l998 Replacing GB l999 (Partial) Safety Glazing Materials in Building Part 2: Tempered Glass 建筑用安全玻璃第 2 部分 : 钢化玻璃 Issued on: August 30, 2005 Implemented on: March 1, 2006 Issued by: General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ); Standardization Administration (SAC) of the People's Republic of China Page 1 of 18

2 Table of Contents Foreword Scope Normative References Definition and Classification Glass Used for Tempered Glass Requirements Test Method Inspection Rules Marking, Packaging, Transportation and Storage Appendix A (Informative) Relevant Explanation for Tempered Glass Page 2 of 18

3 Foreword Articles 5.5, 5.6 and 5.7 in this part are compulsory and the rest are voluntary. At present, "Safety Glazing Materials in Building" (GB 15763) is divided into two parts: - Part 1: fire-resistant glass; - Part 2: tempered glass. This part is Part 2 of GB This part replaces "Tempered Glass" (GB/T ) and the relevant requirements for tempered glass used in curtain wall in "Tempered and Heat-strengthened Glass Used in Curtain Walls" (GB ). Compared with GB/T , the main changes in this part are as follows: - the methods and requirements for fragmentation test were modified; - the requirements for normative references were revised as: the dated and undated normative references were differentiated (Chapter 2 in GB/T , Chapter 2 in this part); - the classification of vertical method tempered glass and horizontal method tempered glass was added (Chapter 3 in this part); - the requirements for surface stress and thermal shock resistance performance of tempered glass used in curtain wall specified in GB were adopted; the requirements for surface stress were modified (Articles 5.4.1, 5.4.3, Sections 6.4 and 6.6 in GB ; Sections 5.8, 5.11, 6.8 and 6.9 in this part); - the requirements for the dimension of the glass round hole were added (Article in this part); - the requirements for appearance quality were modified; - the methods and requirements of transmittance and wind load resistance performance were deleted or reduced; - the sampling rule was modified; - the explanation for stress spot and spontaneous explosion of tempered glass was added (Appendix A in this part). Appendix A of this part is informative. This part was proposed by China Building Material Industry Association. This part is under the jurisdiction of National Technical Committee on Glass in Building of Standardization Administration of China. Drafting organizations of this part: Scientific Institute for Glass of China Academy of Building Material Research, Qinhuangdao Glass Industry Design & Research Institute, and Technical Supervision and Research Center for Building Materials Industry. Page 3 of 18

4 Participating drafting organizations of this part: Shenzhen Nanbo Building Glass Com. Ltd., Guangdong Golden Glass Technologies Limited, Ningbo Jianghua Xinyi Safety Glass Com. Ltd., and Wuxi Xinhui Glass Product Factory. Chief drafting staffs of this part: Yang Jianjun, Qiu Guohong, Han Song, Mo Jiao, Gong Shuyi, Wang Rui, Liu Zhifu, Li Jinping, Zhu Mei, Ai Fazhi, Wu Dehua, Zhuang Dajian, and Xia Weiwen. The previous standards replaced by this part are as follows: GB , GB/T , and the relevant portions for tempered glass used in curtain wall in GB Page 4 of 18

5 Safety Glazing Materials in Building Part 2: Tempered Glass 1 Scope This part of GB specifies the classification, technical requirements, test methods and inspection rules of the tempered glass which is used in building and is fabricated by heat treatment process. This part of GB is applicable to the tempered glass which is used in building and is fabricated by heat treatment process. As for tempered glasses for other purposes other than building (such as industrial equipment, furniture, etc.), if there is no corresponding product standard, this standard may be adopted by reference according to their product features. 2 Normative References The following standards contain provisions which, through reference in this part, constitute provisions of this part. For dated reference, subsequent amendments (excluding corrections), or revisions of any of these publications do not apply. However, the parties who enter into agreement based on this part are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies. GB Laminated Glass GB Float Glass GB/T Test Method for Measurement of Stress in Glass 3 Definition and Classification 3.1 Definition Tempered glass: it refers to the glass undergone heat treatment process. It is characterized by a compressive stress layer formed on its surface. Its mechanical strength and thermal shock resistance strength are improved. And it has special characteristics of fragmentation. 3.2 Classification Tempered glass may be classified into the following types by production process: Tempered glass fabricated with vertical method: the tempered glass fabricated by method of clamping and hanging, during the tempering process. Tempered glass fabricated with horizontal method: the tempered glass fabricated by method of horizontal roller support, during the tempering process. Page 5 of 18

6 Take 4 flat pattern glass specimens for test. 1 of the following items 1) or 2)) shall be met. 1) When the glass is broken, the total mass of the top-10 big fragments of each specimen shall not exceed the mass of specimen in 65cm 2 area. And the length of any glass fragment which has no through-crack and is retained in frame shall not exceed 120mm. 2) When the drop height of the bag is 1200mm, the specimen shall not be broken. 5.8 Surface stress The surface stress of tempered glass shall not be less than 90MPa. Take 3 specimens for test. It is deemed as qualified if all specimens meet the requirements. It is deemed as unqualified if there are 2 specimens failing to meet the requirements. If 2 specimens meet the requirements, take another 3 specimens for test. and it is deemed as qualified if all specimens meet the requirements. 5.9 Thermal shock resistance performance Tempered glass shall be capable of withstanding a temperature difference of 200ºC without damage. Take 4 specimens for test. The performance is deemed as qualified if all the 4 specimens meet the requirements. It is deemed as unqualified if there are more than 2 specimens failing to meet the requirements. If 1 specimen fails to meet the requirements, take additional 1 specimen for test. And the performance is deemed as qualified if the specimen meets the requirements. If 2 specimens fail to meet the requirements, take another 4 specimens for test, and the performance is deemed as qualified if all the 4 specimens meet the requirements. 6 Test Method 6.1 Dimension inspection Dimensions shall be measured with the straight steel ruler or steel tape (the minimum scale is 1mm). 6.2 Thickness inspection Use outside micrometer or the tool with equivalent accuracy, measurement at midpoints of the 4 sides at 15mm away from the glass sides. Arithmetic average of measuring results is the thickness value which shall be rounded to 2 digits after the decimal point (in mm). 6.3 Appearance inspection The inspection shall be conducted on specimen taken from finished products according to the method specified in GB Page 11 of 18

7 6.4 Measurement curvature degree The specimen shall be placed at room temperature for more than 4h. During measurement, the specimen shall be vertical, and 2 cushion blocks shall be padded at lower 1/4 the side length. A straight rule or metal wire shall be used to close fit either sides or diagonal lines of the product, and the spacing between straight side and glass shall be measured with a feeler gauge. The degree of curvature (arch-shaped) shall be expressed by the percentage of ratio of arch height to chord length. In partial waveform measurement, a straight rule or metal wire shall be used for measurement at 25mm away from and in parallel to the glass side (the measuring length is 300mm). The height wave hollow or wave crest shall be measured by feeler gauge which shall be divided by 300mm, and the percentage of the calculated value is the curvature degree (wave-shaped), as shown in Figure Impact resistance test Test specimen shall be the plane tempered glass - same thickness, same type, fabricated with the same process conditions of finished products, and dimension of 610mm (-0mm, +5mm) 610mm (-0mm, +5mm) Test equipment shall comply with the requirements specified in Appendix A of GB The impact surface shall be kept horizontal. When testing curved surface tempered glass, corresponding auxiliary frame is required for supporting A smooth-surface steel ball with a diameter of 63.5mm (mass is about 1040g) shall be placed at 1000mm above the surface of the test specimen. Let it fall freely. The impact point shall be within 25mm of the center of the specimen. Each specimen shall be impacted for only once, so as to observe whether the test specimen is damaged. The test shall be carried out under normal temperature. 6.6 Fragment state test Finished products shall be taken as specimen Test equipment Any device capable of retaining the fragment pattern Test procedure The tempered glass specimen shall be placed freely and flat on the test bed. Scotch tape or other things shall be used to restrict the glass periphery, so as to avoid splashing of glass fragments At the position of the center line of the longest side where is ~20mm away from periphery, a small hammer or punch with a tip curvature radius of 0.2mm±0.05mm is used to impact the test specimen, so as to crush the test specimen. Page 12 of 18

8 measuring points. For irregularly shaped product, its stress measuring points shall be determined through negotiation of the Supplier and the Purchaser Measuring result The arithmetic average of values measured at each measuring point shall be the measuring result. 6.9 Thermal shock resistance performance Place the tempered glass specimen (300mm 300mm) in the dry oven at 200ºC±2ºC for more than 4h, and then take it out and immediately immerse it vertically in 0ºC ice water mixture; more than 1/3 of the specimen height shall be immersed in water, and observe whether the glass is damaged after 5min. Scale-like peeling on glass surface and glass side shall not be regarded as damage. 7 Inspection Rules 7.1 Inspection item Inspection is divided into delivery inspection and type inspection Type inspection The safety performance requirements in the technical requirements are required inspection items, other requirements shall be determined through negotiation between the Supplier and the Purchaser Delivery inspection The inspection items are thickness and deviation, appearance quality, dimension and deviation and degree of curvature. Other inspection items shall be determined through negotiation between Supplier and demander. 7.2 Sampling method by batching Specimens for dimension and deviation, appearance quality and degree of curvature shall be randomly sampled according to those specified in Table 8. Table 8 Sampling Table In piece Batch range Sample size Acceptance number Rejection number 1~8 2 l 2 9~ Page 15 of 18

9 Glass shall be firmly fixed during transportation in order to prevent sliding and overturning; rain-proof measures shall be adopted. 8.4 Storage Product shall be stored in a place without moisture condensation or with rain-proof facilities. Page 17 of 18

10 Appendix A (Informative) Relevant Explanation for Tempered Glass A.1 Stress spot of tempered glass After the glass undergone toughening treatment, different stress distributions may occur on the glass surface due to the uneven heating and cooling in tempering process. It can be learned from photo-elastic theory that the existence of stress in glass may cause birefringence of the light ray. The birefringence phenomenon of light ray may be observed through polarized light. The tempered glass is placed under polarized light. Color and shade changes in different areas on glass surface may be observed. That is the so-called stress spot of tempered glass. Certain polarized light exists in sunlight. The strength of polarized light depends on weather and incidence angle of sunlight. If the tempered glass is observed by polarized glasses or is observed at larger angle in vertical direction, the stress spot of tempered glass will be more obvious. A.2 Spontaneous explosion of tempered glass Tiny nickel sulfide concretion exists in glass. Some concretion may become crystalline, and the volume becomes larger along with time after heat treatment, which causes tiny crack and may further results in spontaneous explosion of tempered glass. The common three methods for reducing spontaneous explosion are as follows: 1) Using sheet with little nickel sulfide concretion, i.e. adopting high quality sheet; 2) Avoiding oversize of tempering stress of glass; 3) Reheat treatment shall be conducted for tempered glass which is generally called detonation or homogenization treatment. The reheat treatment is divided into 3 stages - temperature rise, insulation and cooling. Temperature rise stage refers to the process in which the temperature on glass surface rises from room temperature to 280ºC; insulation stage refers to the process in which the temperatures on all glass surfaces reach 290ºC±10ºC and kept at least for 2h; cooling stage refers to the process in which the temperature cools down to room temperature (75ºC) after the insulation stage is completed. The furnace temperature exceeding 320ºC and glass surface temperature exceeding 300ºC shall be avoid in the whole reheat treatment process, otherwise the tempering stress of glass would be loosened due to overheat which affects the safety. Page 18 of 18