Test Racks

Field exposure test racks were designed and deployed at three different sites with proper protection. 

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FIG. 28-22 Methods for attaching specimens to test racks and to parts of moving equipment. (Mantell, ed.. Engineering Materials Handbook, McGraw-Hill,... 

Fig. 19.27 Slip-in corrosion test rack (after Dillon el...

Where constant depth of immersion is desired in spite of tidal action, it is necessary to support the test racks from a float or raft. 

When implementing an in-service cleaning procedure, use should be made of monitoring equipment, such as corrosion coupons and test racks. 

ASTM D2688 provides a standard test method for measuring the corrosivity of water via weight loss coupons. And the fact is that unless a suitable protocol such as ASTM D2688 is employed for coupon preparation, installation, and subsequent cleaning, variable rates of corrosion are often obtained. Even when protocols are strictly enforced, some variation is usually found, and therefore it is common practice to employ several coupons at the same time, employing a steel or plastic bypass test rack. 

Class F Fire Test of Commercial Standards (12). The test specimen, preconditioned at a temperature of 70 to 75 F. and a relative humidity of 48 to 52%, is supported on the specified test rack at the specified 45 angle with the horizontal, with the board face downward, in a draft-free location. 

Repeated tests rack up a much greater (and ultimately unacceptable) risk. 

Figure 8 (A) PST-19 photostability chamber and (B) their custom-built, walk-in, movable, test racks. Source-. Courtesy of Environmental Growth Chambers (EGC).

Figure 5. Sections of briquettes in Lucite holders for atmospheric exposure in test racks prior to measurements of stone surface roughness and recession. Teflon bars protect portions of surfaces for reference in measurements by laser holographic moire profiling method.

Outdoor Tests. One standard protocol for atmospheric corrosion testing is to mount small rectangular plates (1.6 x 2.4 cm) on a test rack at about 30 from horizontal, about 3 feet off the ground, usually facing south (Figure 4). The test plates are held off the rack by porcelain insulators, and although strictly speaking a new boundary layer should form on each plate, there may be some positional differences in corrosion rate due to turbulence created by the plates first encountered by the wind flow. 

However, considering the atmospheric boundary layer profiles as discussed above, the local velocity at the rack may be considerably lower, especially for test sites in either forested or urban areas. This result emphasizes the need to measure local wind speeds at atmospheric corrosion test sites, at the test rack height. Turbulence intensity measurements might be useful as well. 

Chamber Tests Outdoor Test Racks Large Buildings ... 

According to the standard, unless otherwise specified, exposure racks should face the equator. The standard considers rack position at different latitudes, and the respective rack adjustments at certain periods of the year, and indicates that in most nondesert areas maximum annual UV exposure is provided by exposure at an angle of the latitude angle minus 10°. Besides, the standard considers at-latitude racks, 45° racks, 90° racks, horizontal racks (instead, 5° south exposure is recommended, to provide moisture runoff), and other angle racks. Materials and types of construction of test racks are also considered, as well as instruments for measuring solar radiation, ambient temperature and relative humidity, and their calibration procedures. 

Commercial test rack with the following components from top to bottom CO meter, oxygen meter, NOx meter, total hydrocarbons (THC) meter, and gas conditioning system. Smaller, less accurate, portable combustion analyzers are also available. These analyzers are generally equipped with solid state sensors to measure commonly encountered combustion gases. 

To test for resistance to ozone attack, samples are stretched to 20 or 40 percent strain on a test rack or bent in a loop to produce a surface strain. The specimens are then placed in a chamber equipped with an ozone generator. Usual controlled test concentrations are about 0.25, 0.5, 1, or 2 ppm (parts ozone per milhon parts of air by volume). The test temperature is usually 40°C. The test specimens are inspected at various time intervals until initial cracking occurs. 

Racks were made as per standard [12, 13] using mild steel angles and channels with height and width (1.50 x 2.10 m ). The racks were coated with epoxy paint to prevent rusting. Porcelain washers, brass nuts and bolts were used to fix the test panels at 45° with respect to base. Three types of test panels uncoated, coated and scribed coated were fixed in the racks and test racks at three exposure sites are shown in Figs. 2.6a, b and c. 

Fig. 2.6 a Field exposure test rack at site PI. b Field exposure test rack at site P2. c Field exposure test rack at site P3... 

The initial corrosion test racks were made with tube ends cut from unirradiated fuel and target tubes (Fig. 1.4) They were pretreated to 95°C in deionized water for 30 h to develop a 1 mi thick high temperature boehmite (aluminium oxide) layer on the surfaces. 

TABLE 4.3. POSITION OF SPECIMENS IN THE CHINESE TEST RACK... 

The basin water was periodically analysed. The water was sampled at the appropriate depth, near the test rack. The parameters are listed in Table 7.2. These parameters indicate that the basin water quality did not change significantly. 

The radiation dose rate near the test rack was 0.4-3.9 Gy/h.The dose rate also varied with distance between the test racks and the spent fuel (Table 7.3). 

TABLE 7.3. RADIATION DOSE RATE AROUND THE TEST RACK... 

The test coupon racks were suspended in the IR-8 reactor spent fuel storage basin water. The reactor pool water was purified with a purification system consisting of mechanical and ion exchange filters. The volume of the storage basin water was approximately 30 m. The water was continuously circulated at a flow rate of about 10 L/min in the vicinity of the test racks. The... 

Stainless steel wires were used to suspend the test racks. The location of the immersed racks was at 510 cm from the water surface, 40 cm from the bottom, and 20 cm from the wall of the basin, from the wall of the spent fuel rack and from the other test racks. 

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