Leakage

Class Designation

Maximum

Leakage

Allowable

Test Medium

Test Pressures

Testing Procedures Required for Establishing Rating

Ⅰ

No test required provided user and supplier so agree.

Ⅱ

0.5% of rated capacity

Air or water at 50-125℉

(10-52℃)

45-60 psig or max. operating differential, whichever is lower

Pressure applied to valve inlet, with outlet open to atmosphere or connected to a low head loss measuring device, full normal closing thrust provided by actuator

Ⅲ

0.1% of rated capacity

As above

As above

As above

Ⅳ

0.01% of rated capacity

As above

As above

As above

Ⅴ

0.0005 ml per minute of water per inch of port diameter per psi differential

Water at 50-125℉

(10-52℃)

Max. service pressure drop across valve plug, not to exceed AMSI body rating.

(100 psi pressure drop minimum)

Pressure applied to valve inlet after filling entire body cavity and connected piping with water and stroking valve plug closed.

Use net specified max. actuator thrust, but no more, even if available during test. Allow time for leakage flow to stabilizer.

Ⅵ

Not to exceed amounts shown in following table based on port diameter

Air or Nitrogen at 50-125℉

(10-52℃)

50 psig or max. rated differential pressure across valve plug, whichever is lower.

Actuator should be adjusted to operating conditions specified with full normal closing thrust applied to valve plug seat.

Allow time for leakage flow to stabilize and use suitable measuring device.

NOMINAL PORT DIAMETER

LEAK RATE

Inches

Millimeters

ml Per Minute

Bubbles Per Minute

1

1-1/2

2

2-1/2

3

4

6

8

25

38

51

64

76

102

152

203

0.15

0.30

0.45

0.60

0.90

1.70

4.00

6.75

1

2

3

4

6

11

27

45

Bubbles per minute as tabulated are an easily measured suggested alternative based on a suitable calibrated measuring device such as a 1/4-inch O.D. x 0.032-inch. The tube end shall be cut square and smooth with no chamfers or burrs and the tube axis shall be perpendicular to the surface of the water. Other apparatus may be constructed and  the number of bubbles per minute may vary from these shown, as long as they correctly indicate the flow in ml per minute.