BS 857:1967 (R12):2007 Edition
$167.15
Specification for safety glass for land transport
| Published By | Publication Date | Number of Pages |
| BSI | 2007 | 38 |
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | BRITISH STANDARD BS 857:1967 Specification for Safety glass for land transport |
| 2 | This British Standard, having been approved by the Glass Industry Standards Committee and endorsed by the Chairman of the Chemical Divisional Council, was published under the authority of the General Council on 30 June 1967 Co-operating organizations |
| 3 | Contents |
| 5 | Foreword 1) Only zoned glass is now included for windscreens as it is felt that the uniformly toughened glass, which may obscure the driver’s vision if it fractures, should no longer be used for windscreens. 2) For purposes other than windscreens, provision has been made for the use of glass toughened by chemical treatment, instead of heat treatment, provided it meets the requirements of the standard. 3) The requirements for zoned windscreens have been made more stringent by defining the maximum size of individual particles aft… |
| 7 | 1 General clauses, and optical requirements for windscreens a) Uniform small zone, Type Z, in which the stresses in the glass are substantially even throughout a zone in front of the driver (see Figure 1A). b) Uniform wide zone, Type Z1, in which the stresses in the glass are substantially even throughout a zone extending across the greater part of the windscreen (see Figure 1B). c) Non-uniform wide zone, Type Z2, in which the stresses in the glass vary in intensity over the zone so that, if the glass is fractured, alternate areas break into fine and coarse particles respectively. |
| 8 | Table 1 – Conditions of acceptance for windscreens (optical requirements) 1) Using the “ring and spot” target, there shall be no displacement of the secondary image beyond the point of tangency of the c… 2) Alternatively, using the “ring” target, the primary and secondary images of the circle shall either overlap or touch; this also limits the secondary image separation to a maximum of 15 minutes of arc. 3) There shall not be more than one secondary image. 4) From point to point in the test area there shall be no abrupt change in the displacement of the secondary image. 1) It shall not cause breaks in the projected lines, easily seen by the un-aided eye. 2) Projected lines may be bowed relative to the lines on the screen provided that these projected lines do not overlap the lines on the screen. This is equivalent to a maximum primary deviation of ± 8.4 minutes of arc. 2 Requirements specific to toughened safety glass (including both heat-treated and chemically-treated glass) 2.1 Properties and quality 1) be transparent, translucent or coloured as required; 2) be free from faults which will interfere with vision, appearance or service. |
| 9 | 3) have surfaces resistant to abrasion likely to be encountered in service and to the effects of exposure to the atmosphere; 4) be capable of withstanding normal treatment in the service for which it is supplied. 2.2 Thickness 2.2.1 The available nominal thicknesses of heat-treated safety glass are listed in Table 2 which also gives for information the … Table 2 – Limits of thickness for heat-treated safety glass Table 3 – Limits of thickness usual for heat-treated safety glass for the automobile industry |
| 10 | 2.2.2 Chemically toughened glass is available within the range 1.8 mm to 2.5 mm (0.07 in to 0.10 in). 2.3 Marking 1) The name, registered trade mark or licence number of the manufacturer. 2) In the case of heat-treated toughened safety glass, the letter “T”, or the word “Toughened”, or the word “Tempered”. 3) In the case of chemically toughened safety glass, the letters “CHT”. 4) In the case of a heat-treated safety glass windscreen having a uniform small zone of modified heat-treatment of Type Z, the letter “Z”. 5) In the case of a heat-treated safety glass windscreen having a uniform wide zone of modified heat-treatment of Type Z1, the symbol “Z1”. 6) In the case of a heat-treated safety glass windscreen having a non-uniform wide zone of modified heat-treatment of Type Z2, the symbol “Z2”. 7) In the case of a uniformly toughened safety glass windscreen [see Note to 1.2.4 c)], the letter “W”. 8) In the case of toughened safety glass made from float glass, either the letter “F” or the word “Float”. 9) In the case of toughened safety glass made from plate glass, either the letter “P” or the word “Plate”. 10) In the case of toughened safety glass made from sheet glass, either the letter “S” or the word “Sheet”. 11) An indication that the glass complies with the requirements of this British Standard. It is strongly recommended that in vie… 12) Toughened glass windscreens complying with the requirements of this standard as amended by Amendment No. 1 (AMD 1088) and Amendment No. 2 (AMD 3402) shall be marked with the inscription “BS 857-2:1967”. 2.4 Sampling and acceptance 2.5 Uniformity test 2.5.1 Apparatus. The apparatus shall be as described in Appendix D. |
| 11 | 2.5.2 Procedure. All the glasses taken for test in accordance with 2.4 shall be illuminated by polarized light falling approxima… 2.6 Fragmentation test 2.6.1 General. Notes on methods of supporting the specimens and of carrying out the particle count determination are given in Ap… 2.6.2 Procedure for test. Of each set of five glasses (see 2.5.2) four shall be supported as far as practicable over their whole area, means being provided to prevent any substantial spreading of the fragments (see Appendix E). 1) In the case of a uniformly toughened safety glass, 13 mm (0.5 in) from the longest edge of the glass at the mid-point of that edge. 2) In the case of a small-zone heat-treated safety-glass windscreen or half-windscreen Type Z, on the longitudinal line passing … 3) In the case of a wide-zone heat-treated safety-glass windscreen of Type Z1 or Z2, in the centre of the zone. 4) In the case of a half-screen of Type Z1 or Z2, as near the centre of the zone as possible consistent with the requirements fo… 2.6.3 Particle count and size determinations 2.6.3.1 All particle count determinations on any one piece of uniformly toughened glass shall be completed within 3 minutes of the fracture of that glass. 2.6.3.2 When a uniformly toughened safety glass has been broken in accordance with 2.6.2 1), (see Figure 3A), the particles in a… 1) A segment of radius 7.5 cm (3 in) centred on the point of impact. 2) Two further segments (S) of radius 7.5 cm (3 in) centred on the opposite edge, in the regions of coarsest fragmentation. |
| 12 | 2.6.3.3 When a small-zone heat-treated safety-glass windscreen of Type Z has broken in accordance with 2.6.2 2), (see Figure 3B)… 1) A further count shall be made in a square of 5 cm (2 in) side in the region of the coarsest fracture of the glass outside the… 2) The whole windscreen shall be examined for pointed or flanged long particles, and the number of such particles exceeding 7.5 cm (3 in) in length shall be noted. 3) The presence of any individual particle, of area exceeding 20 cm2 (3 in2), shall also be noted. 2.6.3.4 When a wide-zone heat-treated safety-glass windscreen of Type Z1 or Z2 has been broken in accordance with 2.6.2 3), (see… 1) A further count shall be made of the particles in a square of side 5 cm (2 in) situated in the region of coarsest fracture in… 2) The whole windscreen, excluding a circle of radius 7.5 cm (3 in) centred on the point of impact, shall be examined for pointe… 3) The presence of any individual particle of area exceeding 20 cm2 (3 in2) shall also be noted. |
| 13 | 2.6.3.5 When a heat-treated safety-glass half-screen of Type Z1 or Z2 has been broken in accordance with 2.6.2 4), (see Figure 3… 2.6.4 Test requirements (see also Table 4 and Figure 3A to Figure 3D) 2.6.4.1 For each uniformly toughened glass the following requirements apply: 2.6.4.2 For each small-zone windscreen glass of Type Z the following requirements apply: 2.6.4.3 For each wide-zone heat-treated safety-glass windscreen of Type Z1 or Type Z2, the following requirements apply: 2.6.4.4 For each heat-treated safety-glass half-screen of Type Z1 or Z2, the appropriate requirements of 2.6.4.3 shall apply, except that the particle count in the first assessment relates to one circle only, of area 160 cm2 (25 in2). 2.6.5 Glasses with worked surfaces. Safety glasses with etched, sandblasted, engraved or otherwise “worked” surfaces shall be su… |
| 14 | Table 4 – Summary of requirements for fragmentation tests for toughened safety glass |
| 15 | Table 4 – Summary of requirements for fragmentation tests for toughened safety glass |
| 16 | Table 5 – Conditions of acceptance for toughened safety glass (fragmentation test) |
| 17 | 2.7 Visual transmission a) not less than 75 % in the case of a windscreen; b) not less than 70 % for toughened glass other than windscreens. a) any part of any windscreen which is outside the vision reference zone; b) windows through which the driver when in the driver’s seat is unable at any time to see any part of the road on which the vehicle is waiting or proceeding; c) windows in any ambulance which are not wholly or partly in front of or on either side of any part of the driver’s seat; and d) windows in any public service vehicle, goods vehicle, locomotive, or motor tractor other than windows which: i) are wholly or partly in front of or on either side of any part of the driver’s seat, ii) face the rear of the vehicle, or iii) form the whole or part of a door giving access to or from the exterior of the vehicle.; 3 Requirements specific to laminated safety glass 3.1 Properties and quality 1) be transparent, translucent or coloured as required; 2) be free from faults which will interfere with vision, appearance or service; 3) have surfaces resistant to abrasion likely to be encountered in service and to the effects of exposure to the atmosphere; 4) be capable of withstanding normal treatment in the service for which it is supplied. 3.2 Thickness Table 6 – Limits of thickness for laminated safety glass 3.3 Marking 1) The name, registered trade mark or licence number of the manufacturer. 2) The letter “L” or the word “Laminated” indicating that it is a laminated safety glass. 3) In the case of laminated safety glass made with two or more pieces of plate glass, either the letter “P” or the word “Plate”. 4) In the case of laminated safety glass made with two or more pieces of sheet glass, either the letter “S” or the word “Sheet”. 5) In the case of laminated safety glass made with two or more pieces of float glass, either the letter “F” or the word “Float”. 6) In the case of laminated safety glass made with one piece of plate or float glass and one piece of sheet glass, the letter “C”, the abbreviation “Compo” or the word “Commercial”. 7) In the case of high performance laminated safety glass (meeting the requirements of impact test 3.8) the symbol. 8) In the case of laminated safety glass for use as windscreens the symbol W . |
| 18 | 9) An indication that the glass complies with the requirements of this British Standard. It is strongly recommended that in view… 10) Laminated glass windscreens complying with the requirements of this standard as amended by Amendment No. 1 (AMD 1088) and Amendment No. 2 (AMD 3402) shall be marked with the inscription “BS 857-2:1967”. 3.4 Sampling and acceptance 3.4.1 General. For the purpose of testing a consignment of flat laminated safety glass, specimens may be cut from larger pieces … 3.4.2 Laminated glass for all positions except windscreens 3.4.2.1 Standard laminates. 18 specimens measuring 30.5 cm (12 in) square are required. These specimens shall be submitted to th… 3.4.2.2 High performance laminates. 28 specimens measuring 30.5 cm (12 in) square are required. These specimens shall be submitt… 3.4.3 Laminated glass for windscreens. Unless otherwise specified five wind screens of each shape included in the consignment sh… 3.5 Light stability test 3.5.1 Apparatus. The following apparatus is required: 1) CIE Standard Illuminant A, i.e. a gas-filled incandescent lamp with a colour temperature of 2 854 °K. 2) Equipment for measuring visual transmission. 3) A source of ultraviolet radiation. 3.5.2 Procedure. Three specimens 30.5 cm (12 in) square shall be subjected to the light stability test. The visual transmission of the specimens shall be determined using the light emitted by the Standard Illuminant A (see Appendix C). |
| 19 | 3.5.3 Interpretation of result. In the case of a specimen representing a windscreen, the visual transmission before and after irradiation shall not be less than 75 %. 3.5.4 Additional boil test. After the transmission measurements have been made the same three irradiated specimens shall be imme… 3.5.5 Interpretation of results of additional boil test. The glass itself may crack but no bubbles or other noticeable decomposi… 3.6 Boil test 3.6.1 Procedure. These specimens 30.5 cm (12 in) square shall be immersed, vertically on edge, in water at 66 °C (150 °F) for 3 … 3.6.2 Interpretation of results. The glass itself may crack in this test, but no bubbles or other defects shall develop more tha… 3.7 Fracture and adhesion test 3.7.1 Apparatus. The apparatus for this test shall be as described in Appendix F. 3.7.2 Procedure. Twelve specimens 30.5 cm (12 in) square shall be selected and kept at a temperature of 25 ± 4 °C (77 ± 7 °F) fo… 3.7.3 Interpretation of results 3.7.3.1 Consignment satisfactory. The impact may produce a large number of cracks in the glass; not more than two of the specime… 3.7.3.2 Consignment failed. If more than four specimens break into separate large pieces or if more than four specimens develop … |
| 20 | 3.7.3.3 Conditions for retest. If either three or four specimens break into separate large pieces or if three or four yield a ho… 3.7.3.4 Consignment satisfactory after retest. If of the 24 specimens not more than four break into separate large pieces, and i… 3.7.3.5 Consignment failed after retest. If of the 24 specimens more than four break into separate large pieces, or if more than… 3.8 Impact test for high performance laminates 3.8.1 Apparatus. The apparatus for this test shall be as described in Appendix F. 3.8.2 Procedure. Ten specimens 30.5 cm (12 in) square shall be selected and kept at a temperature of 25 ± 4 °C (77 ± 7 °F) for a… 3.8.3 Interpretation of results 3.8.3.1 Consignment satisfactory. If eight or more specimens retain the ball for 5 seconds, the consignment shall be deemed to comply with this British Standard. 3.8.3.2 Consignment failed. If not more than five specimens retain the ball for 5 seconds, the consignment shall be deemed not to comply with this British Standard. 3.8.3.3 Conditions for retest. If either six or seven specimens retain the ball for 5 seconds a further ten specimens shall be tested. The consignment shall be judged on the basis of the 20 specimens tested. 3.8.3.4 Consignment satisfactory after retest. If of the 20 specimens tested 16 or more retain the ball for 5 seconds, the consignment shall be deemed to comply with this British Standard. 3.8.3.5 Consignment failed after retest. If of the 20 specimens tested 15 or fewer retain the ball for 5 seconds, the consignment shall be deemed not to comply with this British Standard. |
| 21 | Table 7 – Conditions of acceptance for laminated safety glass |
| 22 | 4 Requirements specific to toughened safety glass for use only in railway rolling stock 4.1 General. Toughened safety glass for use in railway rolling stock shall, in addition to the requirements of Section 2, comply with the requirements stated in 4.2 to 4.5. 4.2 Flatness. Applicable only to glasses without intentional bending and where the nominal thickness is equal to, or greater than, 5 mm. 4.2.1 Applications. The applications of glasses to be covered by a flatness tolerance are as follows: 1) side windows including doors with drop windows: single and double glazed, clear, tinted, and translucent; 2) interior doors fitted with fixed and drop windows: single glazed clear and tinted; 3) partitions: single glazed, clear and tinted; 4) shelves: clear; 5) mirrors; 6) miscellaneous applications. 4.2.2 Procedure. Four glasses shall be selected at random from a single production batch and categorized into one of two groups as follows: 4.2.2.1 Category (a). Glasses shall be placed horizontally on to a substantially flat surface. Considering each edge in turn, th… 4.2.2.2 Category (b). Glasses shall be supported vertically without applied load, other than the mass of the glass. Considering … 4.2.3 Calculation. The average thickness of the glass, obtained from three measurements along each edge, shall be subtracted from the values of d recorded in order to obtain an-out-of-flatness value, v, for each edge. 4.2.4 Interpretation of results. The test is considered to have given a satisfactory result if the out-of-flatness value, v, det… 4.3 Tong marks. Tong marks shall not be permitted on those edges of a glass that are required to slide through a runner, e.g. sliding windows and doors, etc. 4.4 Light transmission. Applicable only to frosted or translucent semi-obscured glass for use where a source of light through the glass is required, e.g. kitchen windows. 4.4.1 Apparatus 4.4.1.1 Light source, consisting of an incandescent lamp, the filament of which is contained within a parallelepiped 1.5 mm × 1…. 4.4.1.2 Optical system, consisting of a lens with a focal length of at least 500 mm and corrected for chromatic aberrations. The clear aperture of the lens shall be adjusted in order to obtain a light beam that is substantially parallel. 4.4.1.3 Diaphragm, inserted to limit the diameter of the light beam to 7 ± 1 mm. This diaphragm shall be situated at a distance of 100 ± 50 mm from the lens on the side remote from the light source. 4.4.1.4 Measuring system, consisting of a photoelectric cell with an integrating sphere of diameter of 200 mm to 250 mm. The sph… |
| 23 | 4.4.2 Procedure. Three flat specimens 100 mm square shall be selected. The value of total transmittance for each shall be record… 4.4.3 Interpretation of results. The average total transmittance, when measured in accordance with 4.4.2, shall not fall below 40 %. 4.5 Assessment of visual appearance. The assessment of visual appearance is applicable only to translucent or frosted semi-obscured glass. 4.5.1 Submission. On submission of a series of glasses for test, the manufacturer shall include at least one reference sample wi… 4.5.2 Procedure. Submissions for reapproval, or for audit testing shall be compared with the reference sample retained by the customer. 4.5.3 Interpretation of results. The glass shall be considered satisfactory if there are no significant visual differences between the submission samples and the reference sample. |
| 24 | 1) A lantern slide projector capable of projecting a sharply defined image on to a screen at a distance of 7.6 metres (25 ft). A… 2) A vertical matt white screen approximately 1.2 metres (4 ft) high × 1.8 metres (6 ft) wide, ruled in red lines 1.5 mm (0.06 in) thick at a pitch of 2.16 cm (0.85 in) and inclined at an angle of 30° to the horizontal edge of the screen. 3) A lantern slide bearing lines which shall match exactly with those on the ruled screen [see 2) above] when projected and focu… |
| 27 | Figure 1A – Idealized fracture pattern of small-zone windscreen (Type Z) |
| 28 | Figure 1B, C and D – Idealized fracture pattern of wide-zone windscreens (Types Z1 and Z2) |
| 29 | Figure 2A – Primary vision area for optical tests on windscreens |
| 30 | Figure 2B – Primary vision areas for optical tests on divided windscreens |
| 31 | Figure 3 – Particle count and size determinations (see also Table 4) (continued) |
| 32 | Figure 3 – Particle count and size determinations (see also Table 4) (concluded) |
| 33 | Figure 4 – Apparatus for optical deviation test |
| 34 | Figure 5 – Diagram of typical polariscope |
| 35 | Figure 6 – Frame for fracture and adhesion test and impact test |
| 36 | Figure 7 – Deviation and separation of images due to curvature Figure 8 – Deviation and separation of images due to wedge |
| 37 | Figure 9 – Relationship between optical characteristics of a curved windscreen |
| 38 | BS 857:1967 |
