Water intrusion test

Water-based tests [water intrusion tests (WITs)] [2.36] were developed a few years ago, but it is only recently that they have been promoted as a reliable alternative to the diffusion flow test. 

Bracht, K., Troger, H. The Water Intrusion Test - A New Method for Integrity Testing Hydrophobic Filter Elements. Sartorius, Gottingen, March 1991... 

The principle of the water intrusion test derives from the mercury intrusion test, which (applicable to both hydrophilic and hydrophobic membranes) is restricted to laboratory conditions. The membrane is placed in contact with the fluid (water in the case of the water penetration test, mercury in the case of the mercury intrusion test), and the pressure is increased, with the purpose of forcing the fluid into the pores. The volume of fluid forced into the pores is a measure of pore size and void space volume and thus of filter integrity. 

Hydrophobic gas filter can be tested with the water intrusion test (WIT). Hydrophilic liquid filter are usually tested with water, the often used test method is the pressure decay test (PDT) a variation of the forward flow test (FFT). 

Up to now, only hydrophilic filters have been discussed, which are used for the filtration of aqueous solutirais. Filters that are used for gas filtration such as ventilation filters on tanks and boilers are lipophilic filters. Some hydrophobic filter membranes are used to filter oils and other lipophilic solutions. A physical integrity test with water cannot be performed with this type of filter. For moistening, isopropyl alcohol has been used in the past, but the disadvantage of this substance is that it is highly flammable. Therefore, an alternative method has been developed, which is called the water intrusion test [15, 16]. 

Fig. 2.46. Basic principle of a venting filter for in situ integrity tests. Arrangement of the sterile venting filters for in-line sterilization and integrity tests (I tests). The integrity tests are carried out following the water intrusion method (WIT). In this figure, WIT is carried out only at the primary filter. The secondary filter is installed as a back-up filter (police filter). 1, Primary filter with a 0.22 pm cartridge 2, secondary filter with a 0.22 pm cartridge the secondary filter can be sterilized independent-...

I am an Industrial Hygienist and received a caU this morning to test for mold. The customer is a Periodontal Doctor with ten employees. The building is two floors with a crawl space below them. The professional office building itself is visibly clean, including signs of water intrusion and visible mold. The Crawl space is dry, the wood is clean with some suspect insulation, which I took a bulk sample of. I collected several Air-O-Cell samples and expect to have data within 48 hours. I have advised my client that these are not symptoms that have been associated with mold contamination. 

Water permeability test. Depending on the sea water level, the mortar used for corrosion protection can become wet or completely dry. Continuous fluctuations in moisture content increase the intrusion of damaging substances, which might attack the mortar as well as the steel tower. 

Rarely does composite testing include actual mechanical verification of the final product. The exceptions are filament-wound pressure vessels and some small composite structures, such as golf shafts, that are tested in bending. Many pressure vessels experience some deterioration due to the proof pressure test, which causes transverse stress in the hoop plies that ends up fracturing the matrix in the outer plies and results in a first-ply failure. This is one reason why another failure criterion is invoked for pressure vessels, namely the last-ply failure criterion. However, the failure in the outermost plies reduces the composite s resistance to water intrusion, and consequently the product may have to be recoated with a moisture-resistant paint to satisfy some environmental fears. 

Leaving the refinery, jet fuel has generally no free water and contains only a small quantity of dissolved water. But humidity from the air and tank breathing result in continuous intrusion of water that must be then removed by decanting and filtration. This is why jet fuel needs to be tested for its ability to separate the contained water. 

The subsequent test time lasts 10 minutes. It is not advisable to shorten either the stabilization time or the test time because this could cause increased intrusion values due to insufficiently thorough water distribution on the membrane surface. 

Monitoring pumping tests for the detection of possible intrusion of different types of water (section 4.6). 

Identifying intrusion of water from adjacent wells as a result of pumping tests and in intensively exploited well fields. 

Experimental Procedure. Each sample was first characterized by both mercury intrusion and nitrogen sorption. Mercury intrusion measurements were replicated at least four times, and the solid residues from each analysis were collected and combined after the bulk of the mercury was decanted. These samples were washed free of mercury by using 50% nitric acid (25 mL per 0.5 g of solid) and then washed free of acid by filtering and reslurrying in demineralized water (six times with 50 mL per 0.5 g of solid). The washed samples were then rapidly cooled in liquid nitrogen and freeze-dried (Chemlab SB4). For comparison, samples of material that had not been analyzed with mercury intrusion were washed and dried in a similar manner to test for structural modification caused by the acid-washing technique. 

A series of tests were conducted in the furnace to compare CARS temperature measurements with those acquired with a suction pyrometer [84]. A suction pyrometer is an intrusive probe to measure gas temperature in a flame. The principle of the device is to insert the water cooled probe to the measurement point and draw furnace gases over a thermocouple located at the tip of the probe in an enclosure shielded from flame radiation. The gases are drawn at sufficient velocity to enhance the convective heat transfer to the thermocouple bead. Typically, the flow rate of furnace gases through the probe tip is increased until the thermocouple temperature no longer increases. At this point the thermocouple is assumed to measure the true gas temperature. The disturbance by such a measurement technique can be considerable in the near burner region where chemical reactions are occurring and there is heat release. 

The CFP and Darcy air-permeability data discussed in Sect. 5.1 were correlated with mercury porosimetry (total PSD) and water porosimetry (hydrophobic PSD) before and after the consecutive aging/durability-testing experiments for cell M2. Mercury porosimetry can be effectively used to measure the total porosity and PSD of a GDL. This technique measures all porosity that exists (including constricted or dead-ended pores). The mercury intrusion volume also represents the hydrophobic plus hydrophilic surface domains because mercury is nonwetting for both types of pores. 

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