API STD 622:2018 pdf free download.Type Testing of Process Valve Packing for Fugitive Emissions
4.2.5.1 Using a nominal flow rate of 1 .00 l/min, a 0.050 ml/min leak standard shall produce by definition a 0.050 / (1 .00 liter x 1 000 ml/liter) = 0.005% concentration of test gas by volume or 50.0 ppmv concentration. Therefore, the reading of the leakage monitor shall be tuned to be the verified flow rate of the leak standard in ml/min x 1 000 in ppmv.
4.2.5.2 Verify the sampling flow rate of the leakage monitoring device to be in the range of 0.5 to 1 .5 l/min with a calibrated flow meter.
4.2.5.3 Verify the flow rate through 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 0.050 ml/min to 0.1 00 ml/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 shall be sufficient to fill the tubing and fittings used in the calibration setup.
4.2.5.4 After the flow rate is verified and it is ensured that the test gas has completely saturated the calibrated leak standard, the leakage monitor probe shall be attached to the tee fitting connected to the standard. After stabilization has occurred, calibrate the leakage monitoring device per the manufacturer’s instructions using the calculation in 4.2.5.1 . Leakage for calibration shall be between 50 ppmv and 1 00 ppmv. Calibration shall be performed before the start of each test and the results recorded.
4.3 Packing Selection and Installation
4.3.1 Pre-qualification Packing submitted for type testing shall be certified by the packing manufacturer to be suitable for the conditions indicated in Section 1 of this standard.
4.3.2 Packing Selection
4.3.2.1 Test packing shall be selected from either:
a) a production lot as supplied by the manufacturer; or
b) a distributor stock.
Validation of the selection process shall be provided to the testing facility.
4.3.2.2 Test packing shall be 3.2 mm ( 1 / 8 in.) or 6.3 mm ( 1 / 4 in.) cross-section for the test fixture. Packing 3.2 mm ( 1 / 8 in.) qualifies 3.2 mm ( 1 / 8 in.) to 6.3 mm ( 1 / 4 in), and packing 6.3 mm ( 1 / 4 in.) qualifies 6.3 mm ( 1 / 4 in.) and larger.
4.3.3 Packing Installation A laboratory representative or technician shall install the packing according to the manufacturer’s standard installation instructions, except that the maximum gland flange stud stress shall not exceed 172,300 kPa (25,000 psi). However, the packing stress (load) during the testing shall not exceed the packing manufacturer’s recommended maximum value.
4.3.3.1 Instructions for all packing installations: a) all test fixture components shall be thoroughly cleaned with acetone or equivalent solvent prior to testing;
b) components shall be inspected for damage prior to assembly;
c) caution shall be taken to avoid contact between the stem and gland;
d) fasteners and washers shall be lubricated;
e) gland (flange) height measured from a specific datum shall be recorded;
f) special preparation of the packing or assembly components is prohibited.
4.4 Test Procedure
4.4.1 Test Fluid
The test fluid used shall be dry methane gas, 97 % minimum purity, subjected to a temperature range from ambient to 260 °C (500 °F) and pressures from 0 kPag to 41 37 kPag (0 psig to 600 psig) (see Figure 4).
4.4.2.2 Test Profile
The following describes the testing cycles in Figure 4.
a) Mechanical cycles for the first 5 days are 300 per day and 1 0 cycles during the final mechanical cycling day.
b) Thermal cycle per day is 1 .
— Pressure may be temporarily reduced during heating and cooling.
— Cycling pressure shall be maintained at 41 37 kPag ± 34 kPa (600 psig ± 5 psig).
— Cycles at ambient are 1 50.
— Cycles at 260 °C ± 3 °C (500 °F ± 5 °F) are 1 50.
4.4.3 Leak Measurement 4.4.3.1 Leak measurements shall be conducted at the start of each thermal cycle after the first mechanical cycle and at the completion of every 50 mechanical cycles. For each measurement, a minimum of 10 readings shall be taken over a one-minute duration. The average reading shall be calculated and recorded. If any reading is more than 50 percent greater than the average, except for when the average leakage rates are less than 10 ppmv, the readings shall be repeated.API STD 622 pdf download.API STD 622:2018 pdf free download
