API St 624:2014 pdf free download.Type Testing of Rising Stem Valves Equipped with Graphite Packing for Fugitive Emissions
5.7 The test valve may be equipped with a method of actuation capable of mechanically cycling the valve. The method of actuation should not impose additional side loads on the stem or packing. Running torque values shall be recorded on the first and last cycle of testing.
5.8 Static and dynamic stem leakage measurements shall be taken. See Figure 1.
5.8.1 Leak measurements shall be conducted in still air. Shielding potential leak paths from environmental impacts with a foil enclosure shall be employed during testing. The foil enclosure shall include the stem outside diameter and packing outside diameter.
5.8.2 Leak measurements of the body-bonnet connection and auxiliary connections shall be sniffed. Leakage from body-bonnet and auxiliary connections can affect leak measurement readings and shall be corrected prior to continuation of the test and noted in the report. The detector probe speed shall be approximately 25 mm (1 in.) per second for the bonnet. The instrument shall be adjusted to compensate for the background methane level.
5.8.3 The static/dynamic leakage shall be recorded after a time delay of twice the response time of the instrument.
5.9 The valve shall be equipped with thermocouples for monitoring the temperature during testing. The temperature shall be monitored and recorded at two locations (see Figure 2).
5.9.1 TC-1—affixed to the stuffing box. The thermocouple affixed to the stuffing box shall control the test temperature.
5.9.2 TC-2—at the external body adjacent to the flow path shall be a reference measurement.
5.9.3 TC-2—shall be equal to or greater than TC-1.
5.10 Packing adjustment during type testing is not permitted.
6 Acceptance Criteria The Fugitive Emissions Test Report in Annex A shall indicate “pass” when the measured leakage throughout the test does not exceed 100 ppmv.
7 Leak Test Equipment and Calibration
7.1 Monitoring equipment shall be as described below capable of providing on-board data logging with digital readout. The equipment shall be certified as intrinsically safe for use with the test medium. Data logging may also be performed with a separate data acquisition system.
7.2 The equipment shall meet the following performance requirements in the flame ionization mode:
a) Maximum variation: ±2 % at 100 ppmv.
b) Minimum detectable level (defined as 2 the peak noise): 300 ppb hexane.
c) Maximum response time to reach final value: 3 seconds.
d) Maximum recovery time to return to 10 % of initial value: 5 seconds.
e) Sample flow rate at probe inlet: 0.8 to 1.51 l/min (0.21 to 0.40 gal/min).
7.3 The test equipment shall be inspected prior to each use to ensure against fouling of the detector probe. This shall be done per EPA Method 21 using an external calibration gas with a known methane concentration.
To increase accuracy of readings between different measuring instruments and testers, the leakage device shall be calibrated to known leak rate standards daily prior to testing.
A record of test equipment calibration shall be maintained by the test facility. A porous or sintered metal/ceramic leak standard or similar device shall be used per the following procedure (see Figure 3):
a) Verify the sampling flow rate of the leakage monitoring device to be in the range of 0.5 to 1.5 l/min (0.13 to 0.40 gal/min) with a calibrated flow meter.
b) Verify the flow rate of the calibrated standard leak at a regulated differential pressure using 97 % minimum purity test gas. The calibrated standard leak shall be in the range of 0.025 to 0.075 ml/min (6.6 10 –6 to 1.98 10 –5 gal/ min) of methane. The inverted beaker technique may be used with a sufficient amount of time to collect a measurable amount of sample. The test time should also be sufficient to fill the tubing and fittings used in the calibration setup.API St 624 pdf download.API St 624:2014 pdf free download
