Water spray test

A water spray test is similar to damp heat except that there is the constant presence of small water droplets. The test is made using essentially similar equipment to that for the salt mist test. 

The packages for radioactive shipping must pass certain tests, such as the drop test, corner drop test, compression test, and 30-min water spray test. A special shipping container made of lead that can ship 3 unit dosages of PET radiopharmaceuticals (e.g., 18F-FDG) is shown in Fig. 9.6. 

In the damp heat test, the test pieces are subjected either to static temperature and humidity conditions of 40"C at 93% relative humidity or to 12-1- 12 hour cycling between 23" C at >95% relative humidity and 40 C (or 55 C) at 93% relative humidity. For the water spray test a mist of distilled water at 40 C is sprayed over the surface of the plastic at the rate of 125 to 250 ml per hour per square meter of surface, while for the salt spray test... 

One method of performing the water spray test which is considered to satisfy the conditions prescribed in para. 721 is as follows ... 

These additional tests for a Type A package designed to contain liquids or gases are imposed because liquid or gaseous radioactive material has a greater possibility of leakage than solid material. These tests do not require the water spray test first. 

The tests are the water spray test, the free drop test, the stacking test and the penetration test. Specimens of the package shall be subjected to the free drop test, the stacking test and the penetration test, preceded in each case by the water spray test. One specimen may be used for all the tests, provided that the requirements of para. 720 are fulfilled. 

The time interval between the conclusion of the water spray test and the succeeding test shall be such that the water has soaked in to the maximum extent, without appreciable drying of the exterior of the specimen. In the absence of any evidence to the contrary, this interval shall be taken to be two hours if the water spray is applied from four directions simultaneously. No time interval shall elapse, however, if the water spray is applied from each of the four directions consecutively. 

Water spray test The specimen shall be subjected to a water spray test that simulates exposure to rainfall of approximately 5 cm per hour for at least one hour. 

Fluorescent ultraviolet lamps within an apparatus that allows condensation cycles rather than the water spray typical of xenon arc tests have been developed for plastics testing (279). The spectral cutoff wavelength of the lamps used in the apparatus determines the severity of the test. Ultraviolet B (UVB) 313 lamps allow a significant irradiance component below 290 nm, which is normally filtered out by the earth s atmosphere. Ultraviolet A (UVA)... 

AATCC methods for determining water repeUency are AATCC 22 (spray test) and AATCC 70 (tumble jar dynamic absorption test). In the spray test, water is sprayed against the taut surface of the test specimen to produce a wetted pattern the size of which depends on the repeUency of the fabric. Evaluation is by comparing the pattern with a series of patterns on a standard chart. The latter method evaluates the percentage by weight of water absorbed by a sample after dynamic exposure to water for a specified period of time. 

Water resistance test methods include AATCC 127 (hydrostatic pressure test), AATCC 42 (impact penetration test), and AATCC 35 (rain test). In the hydrostatic pressure test, a sample is subjected to a column of increasing water pressure until leakage occurs. The impact penetration test requires water to be sprayed on the taut surface of a fabric sample from a height of two feet. The fabric is backed by a blotter of predeterrnined weight, which is reweighed after water penetration. The rain test is similar in principle to the impact penetration test. 

Water-repeUent fabrics resist wetting or repel waterborne stains they pass AATCC Test Method 22 (Spray Test). 

In the Spray Test (AATCC Test Method 22), water is sprayed on a taut surface and rating is based on comparison with a standard chart (14). 

In an experiment similar to that referred to on p.4.100, tensile test bars were exposed at Clifton Junction, Manchester, for six months, during which time they were sprayed three times daily with sea-water. Whereas exposure to industrial atmosphere alone had little effect, bars of the same alloys were much more heavily attacked by sea-water spray. 

The most widely used accelerated tests are based on salt spray, and are covered by several Government Specifications. BS 1391 1952 (recently withdrawn) gives details of a hand-atomiser salt-spray test which employs synthetic sea-water and also of a sulphur-dioxide corrosion test. A continuous salt-spray test is described in ASTM B 117-61 and BS AU 148 Part 2(1969). Phosphate coatings are occasionally tested by continuous salt spray without a sealing oil film and are expected to withstand one or two hours spray without showing signs of rust the value of such a test in cases where sealing is normally undertaken is extremely doubtful. 

Humidity tests are generally of more practical use than salt-spray tests, particularly where painting is employed, as the thoroughness of rinsing may be checked by this means. The use of contaminated water can leave... 

Table 15.13. This specification follows good industrial practice, with additional safeguards in rinsing to remove residues to treatment solutions. Nonaccelerated treatments must be followed by a single rinse which may contain chromate accelerated treatments must be followed by three rinses—cold water, hot water and a final chromate rinse. Table 15.14 shows the salt-spray test requirements for phosphate coatings with various finishes without formation of rust the paints and lacquer have the additional requirement that no rust shall be visible beyond 0-2 in (5 mm) from the deliberate scratches and no blistering, lifting or flaking beyond 0-05 in (1-27 mm) from the original boundaries of the scratches.

Fig. 19.11 Effect of specimen position on corrosion in salt-spray tests specimens of cold-rolled steel, (a) 20% NaCl, (i>) synthetic sea-water...

The results will also be influenced by the concentration of NaCl solution sprayed —some metals are affected more by one concentration than another — for example, zinc is corroded most by a concentrated brine (20%), while iron is corroded most by a dilute brine (3%) synthetic sea-water is less corrosive to these metals than either brine. In view of the many other ways by which the conditions within a salt-spray box differ from those of exposure to a natural sea-coast environment, there seems to be no great advantage in making-up complicated synthetic sea-waters for use in salt-spray testing. However, tablets for this purpose are commercially available. 

In addition to the tests made on peaches and apricots, samples of prunes from trees that had been sprayed with parathion, DDT, DDD, basic lead arsenate, and toxaphene at the rate of from 1 to 2 pounds of these insecticides per 100 gallons of water were tested on larvae of Aedes aegypti. The trees had been sprayed on April 20 and June 16, 1948. The fruit was harvested on or about September 10. Prunes from trees that had been treated with 1 quart of tetraethyl pyrophosphate and 12 pounds of sulfur dust per acre on June 15, and harvested about July 6, were tested on larvae of the above named species. None of the prune samples tested in this study exhibited any significant toxicity to mosquito larvae as compared with the unsprayed check. 

In the laboratory the chemical was put into water at the ordinary spray dilution of 1 to 800 and after 24 hours standing the treated water was used as drinking water for test animals. There were no reactions, evidence of poison, or undesirable effects on any animals as a result of these tests, even with long feeding periods. It was not possible to differentiate between test animals and check animals by any of the customary tests. 

A sample of hops which had been treated with tetraethyl pyrophosphate showed a negative chemical analysis. The plant material was also extracted and the extract added to the drinking water of test animals and sensitive insects. The animals and insects that drank this treated water for several days showed no reaction. With the sensitive insects it would have been possible to detect even a few parts per million. In addition, there have been extensive commercial field applications of the chemical in dust and spray form to crops such as apples, pears, grapes, celery, broccoli, Brussels sprouts, and others up to within a few days of harvest there has been no detectable poison residue on any of the crops. The lack of poison residue with use of tetraethyl pyrophosphate is due to the fact that it hydrolyzes within a few hours of application, breaking down into transient nonresidual and nonpoisonous chemicals. Thus it is possible to use tetraethyl pyrophosphate well up to harvest time of food products without danger of residual poison on crops. The fact that the chemical is used in extremely small amounts is a definite advantage in respect to freedom from poison residue. 

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