BS 1868:1975+A1:1990:2010 Edition

This British Standard specifies requirements for cast or forged steel check valves with flanged or butt-welding ends of the following types:

1. swing, for vertical or horizontal flow (see Figure 1);

2. lift:

   1. piston type, for angle or horizontal flow (see Figure 2);

   2. ball type, for angle or horizontal flow (see Figure 3);

   3. ball type, for vertical flow (see Figure 4);

   4. disk type, for vertical flow (see Figure 5).

The terms “vertical”, “horizontal” and “angle” relate to the axes of the body ends.

When swing check valves are used in vertical lines the flow must be in an upward direction. For the purposes of this standard any line with a slope (upward or downward) of 5° or less is deemed to be horizontal. In the case of angle pattern valves the inlet should be vertical.

Nominal sizes, ratings, design, materials, marking and shipping for swing, piston, ball and disk valves for Class 150 up to Class 2500 and of nominal sizes 15 to 600 mm. Appendix for application to piping systems with BS 4504:Part 1.