BS 3463:1975

Co-operating organizations
Foreword
Specification
Section one. General
1 Scope
2 References
3 Definitions
4 Marking
Section two. Tubular glasses for level gauges
5 Material
6 Quality of glass
7 Dimensions
8 Finish of ends
9 Straightness
10 Ovality
11 Thermal shock requirements
Section three. Protector glasses for tubular gauge
                glasses
12 Material
13 Quality of glass
14 Dimensions
15 Finish of edges
16 Inspection under polarized light
17 Thermal shock requirements
Section four. Through-vision and reflex glasses
18 Material
19 Quality of glass
20 Dimensions and shape
21 Flatness
22 Joint faces and edges for reflex glasses
23 Inspection under polarized light
24 Thermal shock requirements
Section five. Circular sight and light glasses
25 Material
26 Quality of glass
27 Dimensions
28 Finish of edges
29 Inspection under polarized light
30 Thermal shock requirements
Section six. Port gauge glasses as used in fittings
                for steam boilers
31 Material
32 Quality of glass
33 Dimensions
34 Tolerances
35 Finish of faces and edges
36 Inspection under polarized light
37 Thermal shock requirements
Section seven. Inspection and thermal shock testing of
                toughened glasses and tubular glasses
38 Inspection
39 Thermal shock testing
Appendices
A Information and recommendations on glasses for
    pressure vessels
B Information to be given when ordering
Tables
1 Diameters, thicknesses and tolerances of tubular
    glasses
2 Lengths of protector glasses for tubular gauge
    glasses
3 Dimensions and tolerances for through-vision and
    reflex glasses
4 Flatness limits for through-vision and reflex
    glasses
5 Preferred thicknesses of circular sight and light
    glasses
6 Limits of bow for circular sight and light glasses
7 Summary of thermal shock testing
8 Recommended maximum working temperatures and
    temperature differentials for through-vision and
    reflex glasses and circular sight and light glasses
Figures
1 Designs for edges of protector glasses
2 Annealed soda-lime glass (design bending stress
    7MN/m2)
3 Toughened soda-lime glass (design bending stress
    35 MN/m2)
4 Annealed borosilicate glass (design bending stress
    7 MN/m2)
5 Toughened borosilicate glass (design bending stress
    14 MN/m2)

Standard dimensions, material and quality of glass for tubular, protector, through-vision and reflex glasses for level gauges, for circular sight and light glasses and for port gauge glasses for high pressure steam boilers. Also thermal shock test methods and requirements.

This British Standard specifies requirements for the main types of observation and gauge glasses for pressure vessels, and also specifies inspection and testing techniques for toughened glasses, under the following main headings.