Test chambers fogging

Fogging This test is a special case of test chamber examination-SVOCs such as plasticizers and flame retardants are precipitated inside the chamber on a cooled surface. The method had initially been developed for examining automotive parts in order to determine the portion of fogging-active substances. It can also be used for examining other products used indoors. The fogging value (in Xg), usually determined over a 14-day period, is a characteristic for the SVOC quantity which can be expected to condense on cold indoor surfaces. The fogging method is based on a convention. If results are to be compared, the studies must be carried out in an identical manner (Uhde et al., 2001 Wensing, Uhde and Salthammer, 2005). 

In a recent study the emissions of several technically relevant phthalates from PVC-coated wallcoverings were measured in emission test chambers under standard room conditions. During a 14-day test period both the chamber air concentrations and the condensation on a cooled plate (fogging) were determined. Chamber concentrations of DBP reached a maximum of 5 pg m (Fig. 7c). Correspondingly, the plasticisers diphenyl phthalate (DPP) and DEHP, which have higher boiling points, reached maximum concentrations of about... 

Figure 2.1-5. View into an open test chamber eontaining a test object (television set) and apparatus for the condensation of SVOCs ( fogging ).

The salt water immersion test (SWI) and the standard salt spray (fog) test (SS) were conducted for both ISPCs and control baking enamels applied on bare CRS, iron phosphated B-1000, and BD+P60 panels. The painted coupons of about 1.0 mil dry film thickness cured at 163 C for 15 minutes were X-cut through the film to the substrate and then either immersed in a 3% NaCI solution (SWI test) or subjected to a continuous salt-solution spray in a test chamber (SS test). After a specified duration of testing, the specimens were removed from the salt solution, and the coated surface was immediately dried. A DUCK brand tape (Manco, Inc., Westlake, OH) was applied over the X-cut and then removed, and the protective performance was... 

A cabinet corrosion test is one in which a test chamber (or cabinet) is used to produce an environment that will cause the occurrence of a corrosion product on a test sample. Some common corrosive environments produced in a test chamber are salt fog, humidity, hot and cold temperatures, ultraviolet exposure, and corrosive gases. These environments may be used individually or in combination with each other. 

ASTM D 5894, Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal, was adopted in 1996 and incorporates a UV exposure cycle following G 85 Annex 5 exposure [9]. The addition of the UV exposure cycle added a weathering effect to the test conditions and produced results that more closely resembled field exposure. Due to the alternating Salt Fog/UV exposure, two separate test chambers are required. 

Although a salt spray (fog) chamber and CASS test chamber may be structuraDy identical, users are discouraged from using a chamber that has previously been used for CASS testing as a salt fog chamber. 

Probably the most widely used test for pitting resistance is salt spray. B 117 describes the expeiimentfd arrangements to be used and mandates the use of 5 wt% NaCl at slightly elevated temperature (35X). The test chamber allows the solution to be sprayed within its confines, creating a salt fog environment around the coupons. Such a constantly moist, salty environment is quite aggressive. 

Figure 11.33 Controlled salt fog test chamber during a humid cycle.

Formulation of effective corrosion-resistant coatings is made difficult by the lack of a laboratory test that can provide rehable predictions of field performance. The most widely used test is exposure in a salt fog chamber. It has been shown repeatedly, however, that the results of such tests do not correlate with actual performance (125). Outdoor exposure of panels can provide useful data, especially in locations where salt spray occurs, but predictions of performance are not always satisfactory (126). 

With this paint system (CR) laboratory tests correlate quite well with the results in the atmosphere. So, in the salt fog chamber the worst paint performance is shown by this system, which is also the only one that shows slight rusting in the ASTM G 53 test. The DEF-1053 test promotes blistering in this system, as well as in the 0/A,A and V systems. 

Panels of high strength aluminum alloy (7075-T6) were used in this study. The panels were approximately 10 x 3 x 0.032 inch (25 x 7.5 x 0.08 cm) in size. The test environments for coating evaluation were (1) a 5% NaCl spray (fog) chamber according to ASTM Standard Method of Salt Spray (Fog) Testing (B117-73), and (2) a modified 5% NaCl/S02 spray (fog) chamber with SO gas introduced periodically - ASTM Standard Practice for Modified Salt Spray (Fog) Testing (G85-84(A4)). In the latter case, a constant spray of 5% NaCl was maintained in the chamber and SO2 was introduced for one hour four tines a day (every 6 hours)( ). Coated test panels were examined for corrosion after one- and two- eek exposure periods. 

Salt Spray Test Panels coated with the standard chromate conversion coating and CMT were compared with each other in their corrosion resistant properties in several ways. The conventional 5% NaCl/S02 fog chamber tests showed excessive corrosion and pitting within one week on chromate conversion coated (COC) 7075-T6 A1 alloy panels. The CMT coated panels were almost uncorroded and without any pits. The plates in Figure 1 show the conditions of the panels after 7 and 14 days exposure in this environment. Even after 14 days exposure the CMT panels were still far better than COC panels. 

The test consists of exposing bare, fully-loaded fuzes to a salt spray (fog) atmosphere of a special chamber, continuously, for 48 hrs to check operability, and-96 hrs to check safety. The equipment of chamber includes an internal salt soln (20 parts of NaCl in 80 ps of w) reservoir, two or more atomizing... 

The test sample was placed in a small fog chamber. A salt fog with a conductivity of 0.15 mS/cm was generated with an ultrasonic dispenser and was transported to the chamber. On the sample, the... 

Highly sophisticated testing and measuring methods are used by the automotive industry to measure the fogging levels and HC emissions (CARB Diurnal Test, Summer Test acc. to VDA 276, Thermodesorption acc. to VDA 278). For adhesive technology, the Summer Test, Fig. 10, provides information on the course and intensity of emissions. The adhesively bonded parts are stored in a chamber for 5 h at 65°C and an air circulation rate of 4001 h. Then the HC components are bound adsorptively and the amount/m of air is measured. Specific adsorption of individual substances that are particularly problematical in terms of envirOTunental coti-tamination can provide a basis for measures targeted to reduce these emissions. 

In a salt spray test the sample is brought in contact with a saline fog in a closed chamber for a certain number of hours. The fog is formed by atomizing a NaCl solution by means of a nozzle. The high corrosivity of the artificial fog simulates that of a marine atmosphere, but the method does not offer a realistic model of more general atmospheric corrosion conditions, because it involves neither the presence of SO2 nor humidity cycling. In order to accelerate the corrosion, acetic acid or copper chloride is sometimes added to the saline solution. 

Unless otherwise agreed upon, the samples are placed at a 15-30 angle from vertical. (Automotive components, however, are often tested in in-car position.) This orientation allows the condensation to run down the specimens and minimize condensation pooling. Overcrowding should be avoided. An important aspect of the test is utilization of a free-falhng mist, which uniformly setdes on the test samples. Samples should be placed in the chamber so that condensation does not drip from one to another. Test durations are typically in 24-h increments and can range from 24-5000 h. (Where salt fog exposure is a part of a more complex test method, exposure time can be as little as 15 min.) Except for sample rotation and daily monitoring of collection rates, the cabinet should remain closed for the duration of the test. 

Annex 3, Acidified Synthetic Sea Water (Fog) Testing, is commonly referred to as the SWAAT test and is often used to test aluminum alloys. Rather than a 5 % salt solution, a synthetic seawater solution is used with the pH adjusted to 2.8-3.0. This aimex includes recommendations regarding the chamber operating temperature for different substrates. The chamber must be equipped with a device to conduct the following cycle 30-min seawater spray (fog), followed by a 90-min period at a relative humidity greater than 98 %. The high relative humidity is achieved by maintaining approximately 1 in. of water in the bottom of the chamber [4]. 

Annex 4, Salt/SO, Spray (Fog) Testing, may be performed using either a 5 % salt solution or synthetic seawater solution. Like the salt spray test, it is conducted at 35°C. The fog may be continuous or intermittent. Depending upon the chosen cycle, the sulfur dioxide is injected into the chamber four times a day for 1 h or within a cycle of VS-h salt fog, A-h SO injection, and 2-h soak [4]. The test was developed by the Navy to simulate exfoliation corrosion on aircraft carriers [6]. 

The most widely used cabinet test is the neutral salt spray (Fog) test (ASTM B 117), which consists of a fog of 5 % sodium chloride within the chamber at 35 C [46. Controversy exists over the validity of B 117 as a performance test because corrosion mechanisms are not always the same as those observed in automobile service. Also, not all materials can be successfully evaluated in the test. However, the value of the salt spray test as a quality assurance test is well documented [46]. Several modifications to the salt spray test have been developed including acetic acid salt spray (ASTM G 85, Annex 1), copper accelerated acetic acid salt spray (ASTM B 368), acidified synthetic seawater fog (ASTM G 43, Method of Acidified Synthetic Seawater (Fog) Testing), and modified salt spray (ASTM G 85). ASTM G 85 also includes cyclic tests. 

Laboratory exposure tests are usually conducted in chambers similar to that described in ASTM B 117, Test Method of Salt Spray (Fog) Testing. Because the environment is more corrosive than the salt fog described in ASTM B 117, the variations described in ASTM G 85, Practice for Modified Salt Spray (Fog) Testing, are often used. Some investigators have used a modified procedure in which the test coupons are mounted over holes on the outside wall of the exposure chamber so that they can be subjected to a thermal gradient [35]. Outside mounting of the coupons also affords the opportunity to conduct in situ electrochemical impedance measurements. 

Similar panels were tested in salt spraying (fog) chamber (1500 hours) under the operating conditions specified in ASTM B 117. After finishing the tests, the panels were evaluated according to ASTM D 1654 (Method A, in X-cut and Method B, in the rest of the surface) to establish the degree of rusting. 

The performance of panels tested during 1500 hours in salt spraying (fog) chamber (35+1 °C pH 6.5-7.2 continuous spraying of 5 1% w/w of NaCl solution) are shown in Figure 4 and Figure 5. They include only the average values of the tests p>erformed in the failure in X-cut (Method A) and over the general area of panel (Method B). 

Many tests are based on constant condensation or humidity. Incidentally, constant condensation is not the same as humidity testing. Condensation rates are higher in the former than the latter because, in constant condensation chambers, the back sides of the panels are at room tempaature and the painted side faces water vapor at 40 C. This slight temperature differential leads to higher water condensation on the panel. If no such temperature differential exists, the conditions provide humidity testing in what is known as a tropical chamber. The Cleveland chamber is one example of condensation testing a salt spray chamber with the salt fog turned off, the heater turned on, and water in the bottom (to generate vapor) is a humidity test... 

The oldest and most widely used cabinet test is ASTM B117 [Test Method of Salt Spray (Fog) Testing], a test that introduces a spray in a closed chamber where the test specimens are exposed at specific locations and angles [24]. The concentration of the sodium chloride (NaCl) solution has ranged from 3.5 to 20 percent. There is a wide... 

ASTM method D 2132 outlines the procedure for determining dust and fog tracking and erosion resistance of electrical insulating materials. The test is carried out in a fog chamber with a standardized dust applied to the sample surface. Failure is characterized by the erosion of the specimen or tracking. ASTM D 2302 also describes the test for differential wet tracking resistance of electrical insulating... 

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