Techniques for Hydrostatic test

Leaks in pressure yacht such as pipelines, plumbing, etc can be found with one of the most ordinary methods knows as hydrostatic test. In short it is utilized to test mechanisms for leaks by pressurizing them within with a liquid. This testing technique can be utilized or tested on piping, tanks, valves and containers with fused or fixed sections. This technique of testing should not be perplexed with the Hydrostatic Body Fat Test that utilizes the philosophy of resilience to analyze a person's body fat. Hydrostatic tests, as a supplementary recital authenticate fluid stress vessels. By utilizing this mean of test we can uphold protection standards and sturdiness of a vessel eventually. Recently manufactured portion are firstly competent by means of the hydrostatic test and repeatedly re-qualified at usual hiatus by the proof pressure test which is also known as modified hydrostatic test. With the help of Hydrostatic we can check gas cylinder or a boiler is checked for leaks or defect. This method is very vital as such containers can blow up if they fail when containing dense gas.
Normally the benefits of this test is that it helps to measure the pressure capacity, manually control the systems, is fully automatic, precise control, is fully instrumentation and data logging, has strain measurement system, temperature control, etc.
This method requires that a constituent be entirely filled with a liquid such as water. Pressure is gradually applied to the liquid until the required pressure is reached. This pressure is detained for the necessary time at which point the constituent is examined visually to establish leaks.
There are two types of hydrostatic measures that are included in the method:
Firstly the pressure drops method with compassion. This technique would never place leaks but can be used to determine entirety system leakage. It is important that the technique be familiar with that water additives can speed up the flow of water through leaks and make the test more responsive.
Secondly is the Visual examination. This practice can attain compassion. This extensive bound in compassion is accomplished by not only plummeting confrontation to the liquid flow through leaks but by also enhancing the visibility of leakage proposition.One of the more attractive proposals is that it is frequently more helpful to pulsation the pressure throughout a test than it is to clutch a steady pressure. This is particularly true when the organization being tested will not function at a stable pressure or it is being tested at pressures well over those predictable during standard use. The cause for this prerequisite is that little leaks are not forever still. Several enlarge under pressure, several indentures Severe over pressurization may in reality close some leaks overall.

Salt Spray Weathering

Salt spray testing under ASTM B117 conditions subjects the test samples to conditions that are actually more corrosive than usual “real world” exposure. This is because the test uses sodium chloride in de-ionized water and usually lacks the moderating effects of other dissolved salts such as those containing calcium and magnesium, which tend to be somewhat protective.

is the most popular form of testing for protective coatings. These tests have been used for more than 90 years as accelerated tests in order to determine the degree of protection afforded by both inorganic and organic coatings on a metallic substrate. The most widely used salt spray (fog) tests are described below.

The neutral salt spray (fog) test (ASTM B 117): is perhaps the most commonly used salt spray test in existence for testing inorganic and organic coatings, in particular where such tests are used for material or product specifications. The duration of the test can range from 8 to over 3000 hours, depending on the product. A 5% sodium chloride solution containing not more than 200 parts per million (ppm) total solids and with a pH range of 6.5 to 7.2 is used. The temperature of the salt spray chamber is controlled to maintain 35 + 1.1 or – 1.7Þ C (95 + 2 or -3Þ F) within the exposure zone of the closed chamber.

The acetic acid salt spray (fog) test (ASTM G 85, Annex A1): is also used for testing inorganic and organic coatings, but is particularly applicable to the study or testing of decorative chromium plating and cadmium plating on steel or zinc die castings, as well as for the evaluation of product quality. This test can be as short as 16 hours, although it normally ranges from 144 to 250 hours or more. Similar to the neutral salt spray test, a 5% sodium chloride solution is used, but the solution is adjusted to a pH range of 3.1 to 3.3 by the addition of acetic acid. The temperature of the salt spray chamber is controlled to the same temperature range as for neutral salt spray.

The copper accelerated acetic acid salt spray (fog), or CASS test (ASTM B 368): is primarily used for the rapid testing of chromium plating on steel and zinc die castings. It is also useful in the testing of anodized, chromated, or phosphated aluminum. The duration of this test ranges from 6 to 720 hours. A 5% sodium chloride solution is used, with one gram of copper (II) chloride dihydrate added to each 3.8 liters of salt solution. The solution is then adjusted to a pH range of 3.1 to 3.3 by adding acetic acid. The temperature of the salt spray chamber is controlled to the same temperature range as for neutral salt spray and for acetic acid salt spray.