SCSSSV gas test. Draft 1, issued 15 May 2010. WORK version.

This Worksheet calculates the average flow rate of gas through a valve into a closed space during a pressure test, in SCF/min or m3/min. The procedure is defined in API RP14B and to summarise is;

1. Apply the required test pressure below the valve.

2. Bleed off above the valve and record the starting pressure.

3. Record the pressure buildup after 60 minutes (or optionally use a different time interval).

4. Look up the gas deviation factor at 1 bara (14.7 psia) and at the final pressure.

5. Record the temperature at the valve.

6. Note the volume above the valve (into which the gas flowing across the valve entered).

Initial test gauge pressure, P_test1

(The worksheet will convert this to absolute pressure)

Final test gauge pressure, P_test2

Test duration, minutes, t_test

Volume above the SCSSSV, v_test

Temperature at the SCSSSV, T_test

Gas deviation factor at 1 bar, CZs

If the gas deviation factors are not known, use 1 for each. This then assumes a perfect or ideal gas.

Final gas deviation factor, CZ_test

Click here when any values are modified to update the result.


Average flow across valve during the test, equivalent Standard Volumes per minute.

NOTE - the API maximum flow rate to pass the test is 0.425 m3/min (25.485 m3/hour) or 15 ft3/min (900 ft3/hour).


1. API Recommended Practice 14B "Design, Installation, Repair and Operation of Subsurface Safety Valve Systems" (incorporates ISO 10417:1993)

2. All of the mathematical variable names are given in accordance with the Standard Variable Naming Convention. The latest version is available at .