Hydraulic tests

Some partners of the programme have already obtained the authorization to make in-service pneumatic test monitored by acoustic emission instead of hydraulic tests. 

Tile new Pressure Equipment Directive (P.E.D.) established by the European Commission recognize acoustic emission as a complementary method which can be used to monitored pneumatic test when hydraulic test could not be perform. 

In many applications a pressure vessel may be tested for safety simply by hydraulic testing to a pressure that is higher - typically 1.5 to 2 times higher - than the normal operating pressure. Steam boilers (Fig. 16.7) are tested in this way, usually once a year. If failure does not occur at twice the working pressure, then the normal operating stress is at most one-half that required to produce fast fracture. If failure does occur under... 

Slides Ultrasonic crack detection hydraulic testing. 

Before first use hoses to be inspected visually internally and externally and tested at proof pressure. Repeat at least annually and include check on electrical resistance. The resistance of the complete assembly should be not more than 15 ohms, unless the hose is intended to be non-conducting when resistance should be at least 25 000 ohms. Inspect hose daily when in use. Hoses used at monobuoys should also be hydraulically tested. 

Establish field construction hydraulic test pressures for each process equipment. Sometimes the equipment is blanked or blocked off, and no test pressure is applied in the field, because all pressure equipment must be tested in the fabricators or manufacturers shop per ASME Code. 

Date of last hydraulic test (if any), and pressure applied. 

Pneumatic testing of equipment should only be used when hydraulic testing is impracticable appropriate safeguards, e.g. pre-inspection, reduction of the internal gas space, pressure relief, and use of a blast pit or enclosure, are necessary. 

Maximum weight of the vessel and contents under the hydraulic test conditions. 

Note the test condition is with the vessel full of water for the hydraulic test. In estimating total weight, the weight of liquid on the plates has been counted twice. The weight has not been adjusted to allow for this as the error is small, and on the safe side . 

The national pressure vessel codes and standards require that all pressure vessels be subjected to a pressure test to prove the integrity of the finished vessel. A hydraulic test is normally carried out, but a pneumatic test can be substituted under circumstances where the use of a liquid for testing is not practical. Hydraulic tests are safer because only a small amount of energy is stored in the compressed liquid. A standard pressure test is used when the required thickness of the vessel parts can be calculated in accordance with the particular code or standard. The vessel is tested at a pressure above the design pressure, typically 25 to 30 per cent. The test pressure is adjusted to allow for the difference in strength of the vessel material at the test temperature compared with the design temperature, and for any corrosion allowance. 

Void distribution measurement. The local void fraction is an important parameter in the reduction and analysis of hydraulic test data in two-phase flow. In addition to photographic visualization and fiber optic video probes for observation (Donaldson and Pulfrey, 1979), the following other methods are currently available, each with its own unique set of attributes and drawbacks (Delhaye et al., 1973 Delhaye, 1986 Andreychek et al., 1989). 

ORNL small-break LOCA tests Experimental investigation of heat transfer and reflood analysis was made under conditions similar to those expected in a small-break LOCA. These tests were performed in a large, high-pressure, electrically heated test loop of the ORNL Thermal Hydraulic Test Facility. The analysis utilized a heat transfer model that accounts for forced convection and thermal radiation to steam. The results consist of a high-pressure, high-temperature database of experimental heat transfer coefficients and local fluid conditions. 

Hydraulic test at 1.5 times working pressure (1 hour)... 

This visual inspection should be done before the tank is hydraulically tested since rusting formed immediately after the hydraulic test will camouflage the defects on the surface. 

Any leaks at the metal joints found during hydraulic testing should be repaired before the start of rubber lining and not during the operation. 

Dye penetrant test on the welded surfaces for any blowholes should be conducted before the equipment, pipes and fittings are subjected to hydraulic testing. 

Pressure vessels and pipes should be subjected to hydraulic testing before rubber lining. 

After acquisition of experimental data, flowsheet calculations were carried out. A theoretical recovery of cesium was fixed at 99.99%. Hydraulic tests and chemical transfer tests were first carried out with centrifugal contactors, then with pulsed columns, first on simulated effluents and then on actual effluents. 

In the first pilot test, 12 metric tons of 14-40 mesh (1.4-0.4 mm) SMZ, manufactured at a cost of about 460 per metric ton, was used as the barrier material. Intensive sampling showed that much of the contaminant plume was being deflected under and around the SMZ barrier. Hydraulic testing failed to conclusively isolate the cause(s) of the flow restriction but suggested that a partially plugged barrier frame, along with a possible decrease in SMZ permeability, were responsible. 

The test gag is intended to block the opening of the valve while a hydraulic test on the system is performed. It physically blocks the spindle from moving upwards, preventing the valve from opening. 

This device, however, is frequently misused and dangerous if not removed after hydraulic tests or before a new installation. 

Test gag Remove test gag. Sometimes test gags are incorrectly used to protect valve during transport or during hydraulic testing and often their removal is forgotten. 

Automated water-level measurement can be achieved by deploying pressure transducers that can be set to log data as frequently as every second if required. Loggers also record temperature and are able to compensate for altitude, water density, temperature and barometric pressure. These are routinely used when undertaking hydraulic tests on a well but are also useful to provide accurate, regular, longterm water level data and are invaluable for groundwater flow direction calculations. 

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