Pressure tests testing procedures

The following points must be considered when establishing a pressure testing procedure (whether it be a tightness or strength test). The procedures to be followed... 

When constmction is complete, the pipeline must be tested for leaks and strength before being put into service industry code specifies the test procedures. Water is the test fluid of choice for natural gas pipelines, and hydrostatic testing is often carried out beyond the yield strength in order to reHeve secondary stresses added during constmction or to ensure that all defects are found. Industry code limits on the hoop stress control the test pressures, which are also limited by location classification based on population. Hoop stress is calculated from the formula, S = PD/2t, where S is the hoop stress in kPa (psig) P is the internal pressure in kPa (psig), and D and T are the outside pipe diameter and nominal wall thickness, respectively, in mm (in.). 

Equipment Tests. Procedures for rigorous, detailed efficiency determination are available (ASME Test Codes) but are rarely used. For the objective of defining conservation potentials, relatively simple measurements are adequate. For fired heaters, stack temperature and excess O2 ia stack should be measured for turbiaes, pressures (ia and out) and temperatures (ia and out) are needed. 

Other Equipment Cost ModiEers. Temperature, pressure, or corrosive conditions can act as modifiers of the base cost by requiring thicker vessel walls, more expensive alloys, special seals, more expensive fabrication, and special testing procedures. Separate materials and process severity factors for temperature, pressure,and material,, multiply the base (mild steel) cost as ... 

Static performance measurements related to positioner/ac tuator operation are conformity, measured accuracy, hysteresis, dead baud, repeatability, and locked stem-pressure gain. Definitions and standardized test procedures for determining these measurements can be found in ISA-S75.13-1989, Method of Evaluating the Performance of Positioners with Analog Input Signals and Pneumatic Output . 

Implement procedures for leak/pressure testing of jacket, coil or heat exchanger prior to operation... 

Gas flows are often determined by measuring the associated pressures. Figure 32-4 illustrates several different pressure measurements commonly made on systems carrying gases. Static pressure measurements are made to adjust the absolute pressure to standard conditions specified in the test procedure. 

Procedural Checklist Ensures Safe, Complete Pressure-Testing and Purging of Process Equipment... 

After the heat run, the compressor continues to run on air and the highest pressure practical is imposed, while the speed is set to the normal operating speed. The capacity and power should be noted as well as bearing temperature and the other instrumentation used during the test. If oil buffered seals are used and the test run is expected to exceed 250°F, the test procedure may have to be modified to avoid the possibility of an explosion hazard. 

Stable Detonation A detonation that progresses through a confined system without significant variadon of velocity and pressure character-isdcs. Eor atmospheric condidons, typical velocides range between 1600 and 2200 m/s for standard test mixtures and test procedures. 

Testing Procedures for Pressure Relieving Devices Discharging Against Variable Back Pressure... 

Testing Procedures for Pressure-Relieving Devices Discharging Against Variable Back Pressure, API-RP-525, American Petroleum Institute, New York, N.Y... 

Plastic Viscosity and Yield Point. Plastic viscosity and yield point measurements are obtained from a direct indicating viscometer. Due to the temperature effect on the flow properties of oil-base mud, the testing procedure is modified. The mud sample in the container is placed into a cup heater [23]. The heated viscometer cup provides flow property data under atmospheric pressure and bottomhole temperature. 

Factory tests establish the pressure head, power, efficiency and NPSH over the complete flow range the pump can deliver running at design speed. British Standard, DIN standard or ANSI standard codes or national variations from such main codes lay down the manner of test procedure, and a minimum requirement is quite often defined by industry codes such as API 610. This is not the place to discuss instrument accuracy, as the codes lay down the limits possible from conventional instruments. There are two main classes of test the commercial requirements normally possible in the maker s test plant and high-accuracy tests that are only possible by using substandard instruments and very sophisticated techniques. 

Three general test procedures used to measure the permeability of plastic films are the absolute pressure method, the isostatic method, and the quasi-isostatic method. The absolute pressure method (ASTM D 1434, Gas Transmission Rate of Plastic Film and Sheeting) is used when no gas other than the permeant in question is present. Between the two chambers a pressure differential provides the driving force for permeation. Here the change in pressure on the volume of the low-pressure chamber measures the permeation rate. 

Engineering specification and purchasing procedures are essential to ensure that all items are to the design specification and to comply with company or national standards. During installation the features to consider are foundations, selection of materials, fabrication, assembly, supports, pressure testing etc. 

Among some of the test procedures that may be used for monitoring package integrity over time are dye immersion testing using either pressure or vacuum,... 

The apparatus used to determine the explosive nature of vapors is shown in Figure 6-14. The test procedure includes (1) evacuating the vessel, (2) adjusting the temperature, (3) metering in the gases to obtain the proper mixture, (4) igniting the gas by a spark, and (5) measuring the pressure as a function of time. 

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