Type tests

Type tests of polyurethanes are used to evaluate polyurethanes using standardized methods. The tests are a characteristic of the polyurethane being evaluated but do not represent actual field conditions. 

The samples need to be brought to controlled test conditions before the test is carried out. If they were used as a quality control test, the product in many cases would be at the customer before the test was completed. A typical example is that tests such as the tensile tests require a week to settle down before the test is carried out after the 18-hour cure cycle. In many cases an approximate value is obtained by testing as soon as the sample has reached room temperature after it has had its full cure. 

---

The method was applied for determination of the quality of the detection media on test pieces following the type testing of the European standard [4] in order to check the validity of the method. The other application was the determination of the visibility in dependance of the variations of the inspection parameters (application of the detection medium, magnetization, inclination, viewing conditions) in a range which may appear in the practical inspections. The results leads to conclusions on the visibility level which is a measure of the probability of recognition for the indication that means of the reliability of the method. 

Following the draft european standard [4] for type testing, quality of the detection media shall be verified on 2 reference blocks as shown in Fig. 2. On the reference block No. 1, created by Mr. Dickhaut [7], (Nr. 3 of the MTU) the indications shall be valuated by comparison with the indications of a detection medium with known quality. On reference block No. 2 (AFNOR-C A-C) the lenght of the indications shall be determined as a measure for the quality. 

With the objective determination of the visibilitity of magnetic particle indications quantitative researches on the influence of the inspection parameters will be possible. The first part deals with the type testing of detection media which is as well on the course of adoption for type testing of liquid penetrant systems (prEN 751-2). 

The scale-up of filtration centrifuges is usually done on an area basis, based on small-scale tests. Buchner funnel-type tests are not of much value here because the driving force for filtration is not only due to the static head but also due to the centrifugal forces on the Hquid in the cake. A test procedure has been described with a specially designed filter beaker to measure the intrinsic permeabiHty of the cake (7). The best test is, of course, with a small-scale model, using the actual suspension. Many manufacturers offer small laboratory models for such tests. The scale-up is most reHable if the basket diameter does not increase by a factor of more than 2.5 from the small scale. 

Indicators can determine if uniform steam penetration has been achieved during a Bowie Dick-type test. Produced in the form of sheets (23 X 30 cm), chemical indicators are capable of uniform color change over their entire surface when exposed to pure saturated steam under test conditions. Nonuniform color development is an indication of failure of the test. U.S. and international stands for the performance and accuracy of chemical indicators have been pubHshed (13,14). 

Name Type Test organisms Resistance standard... 

Available Chlorine Test. The chlorine germicidal equivalent concentration test is a practical-type test. It is called a capacity test. Under practical conditions of use, a container of disinfectant might receive many soiled, contaminated instniments or other items to be disinfected. Eventually, the capacity of the disinfectant to serve its function would be overloaded due to reaction with the accumulated organic matter and organisms. The chlorine germicidal equivalent concentration test compares the load of a culture of bacteria that a concentration of a disinfectant will absorb and still kill bacteria, as compared to standard concentrations of sodium hypochlorite tested similarly. In the test, 10 successive additions of the test culture are added to each of 3 concentrations of the hypochlorite. One min after each addition a sample is transferred to the subculture medium and the next addition is made 1.5 min after the previous one. The disinfectant is then evaluated in a manner similar to the phenol coefficient test. For equivalence, the disinfectant must yield the same number of negative tubes as one of the chlorine standards. 

Tuberculocidal Test. The tubercle bacillus is resistant to disinfectants because the cells are protected with a waxy coating that is not readily penetrated. The tuberculocidal test is a use dilution practical type test that employs porcelain cylinders. The bacteria are different from those in the use dilution method (Table 10), the incubation time is longer, and the details of the procedure are different. For example, in the tuberculocidal test the test is divided into two parts, a presumptive test and a confirmatory test. The former employs Mycobacterium smegmatis and the latter employs Mycobacterium bovis (BCG). For the presumptive test the incubation time is 12 days, as against 48 hours for other bacteria used in the use-dilution method. For the confirmatory test the incubation time is 60 days, with an additional 30 days in case there is no growth. As shown in Table 10, the concentrations of the phenol standard are higher than used with other bacteria. 

Factors may throw off these rates—these are outlined in ASTM G3I, Standard Practice for Laboratory Immersion Corrosion Testing of Metals. Coupon-type tests cannot be correlated with changing plant conditions that may dramaticahy affect process equipment lifetimes. Other methods must be used if more frequent measurements are desired or correlation with plant conditions are necessary. 

Low voltage switchgear and controlgear assemblies. Type tested and partially type tested assemblies 8623 (Part-1) 1993 BS EN 60439 1/1994... 

Type tests are conducted on the first machine of etich type or design to determine the characteiislics and demonstrate its compliance with the relevant Standards. These tests provide a standard reference for any subsequent similar machine. The following ire Ihe type tests according to I EC 60034-1 ... 

These values are meant for type tests only. 

Type tests are conducted on the first enclosure of each voltage, current rating and fault level to demonstrate compliance with electrical and constructional design parameters. The tests provide a standard reference for any subsequent enclosure with similar ratings and constructional details. The following tests may be conducted to demonstrate verification of the following ... 

Routine tests are conducted on each completed assembly, irrespective of voltage, eurreni, fault level and constructional details and whether it has already undergone the type tests. The following steps will form routine tests ... 

The tests against step numbers I, 2 and 3 in Section 14.2,2 are of a general nature and no test procedure is prescribed. The rest are similar to the tests covered under type tests. The procedures of tests and requirements of test results will remain the same as discussed earlier. 

Type tests These are conducted on a finished voltage or current transformer, one of each design and type, to verify their compliance with the design data and relevant Standards. 

I Type tests These will cover the following tests ... 

This lest is same as for item (iv) (a), under type tests. 

This test is the same as under type test item (vi) 3 Special tests... 

Description Routine test Type test Routine test Type test... 

---