For Check Valve Below 1.5" Size API602 is Applicable?

My reply to your email (Friday, February 10, 2012 7:46 AM):

• API 600 "Steel Gate Valves-Flanged and Butt-Welding Ends, Bolted and Pressure Seal Bonnets

1.1 Scope

1.1.1 This standard covers steel gate valves with flanged or butt-welding ends in sizes NPS 1 through 24. These sizes correspond to nominal pipe size s in ASME B36.10M.

1.1.2 This standard covers valves in Classes 150 through 2500 as specified in ASME 16.34

1.1.3 This standard covers requirements for a heavy-duty style of bolted bonnet gate valves for petroleum refinery and related applications where corrosion, erosion, and other service conditions indicate a need for full port openings, heavy body wall sections, and large stem diameters. Covered are requirements for outside screw-and-yoke (OS&Y) valves with rising stems, nonrising handwheels, and various types of gate configurations. In addition, Appendix A of this standard covers requirements specifically for pressure seal bonnet gate valves for both a heavy-duty style and a general purpose style for applications where less arduous corrosion and erosion service conditions are confronted or materials are selected so as to ameliorate these conditions.

• API 602 "Compact Steel Gate Valves-Flanged, Threaded, Welding, and Extended-Body Ends"

1 Scope

1.1 This standard covers flanged-end, threaded-end, socket-welding-end, and butt-welding compact steel gate valves, including extended-body type, corresponding to nominal pipe sizes in ASME B36.19M as follows:

(a) Flanged-end and butt-welding-end in sizes 4 and smaller,

(b) Threaded-end and socket-welding-end in sizes NPS 2 and smaller. The following valves are specifically covered by this standard:

a. Class 800 valve with threaded, socket-welding, or butt-welding ends

b. Class1500 valve with threaded, socket-welding, butt-welding, or flanged ends; an OS&Y with rising stem and bolted packing-gland flange; and a bolted, welded, or threaded-and-seal-welded bonnet.

c. Class 150, 300, and 600 flanged-end or butt-welding-end OS&Y valves with rising stem; bolted packing-gland flange; and a bolted, welded, or threaded-and-seal-welded bonnet.

d. Class 800 and Class 1500 extended-body valves conforming to items and b above, except with male by female ends in sizes NPS 1/2, 3/4, 1-1/2, and 2 and in size NPS 3/4 male by NPS 1/2 female.

e. Threaded-end male extension for Class 1500 or for size NPS 1/2 in Class 800 are not covered by this standard.

f. Class 150, 300, 600, 800, and 1500 valves with bellows stem seal with the additional requirements covered in Appendix A.