The strainers covered by this specification are intended for general service to protect regulating valves, orifices, pumps, and other piping equipment from damage or faulty operation which would result from entrained sediment particles.

The following ranges of perforation sizes and wire mesh numbers are acceptable.

a. Perforation diameters, inches (approximate):

0.020 to 0.023

0.027 to 0.033

0.040 to 0.050

0.057 to 0.063

0.090 to 0.105

0.120 to 0.130

b. Mesh numbers - 20, 40, 60, 80, and 100.

The ratio of the net effective strainer area to the area of the pipe in an indirect index of the resistance to flow through the strainer. The ratio cited in 3.9.6 is a minimum value for the range of sizes covered by this specification. Many designs of strainers provide for higher area-ratios. The area-ratio is dependent upon the size of opening and the total surface area of the element, and varies with the size of the strainer. If a higher ratio is required, manufacturer's literature should be consulted to ascertain availability of the required area-ratio,.