Test chambers standardization

Tests for elastomer resistance to air have to be considerably accelerated in the laboratory by exposure to pure oxygen (pressure test, 21 bar, 70°C) or in the ozone test chamber (standard pressure, 50-200 ppm ozone, 25°C, s. Section 2.2.8). While oxygen influence is rated as a percentage loss of properties, comparable to heat aging tests in air, ozone influence is evaluated according to crack formation in the rubber transverse to the tensile or bending direction (evaluation levels 0 to 3) [229]. 

The standard astm test method (D-1149-64) for rubber damage includes a test chamber (volume, 0.11-0.14 m ) through which ozonized air flows at a rate greater than 0.6 m/s. Because the residence time of the ozonized air in the test chamber is about 1 s, the ozone may be expected to reach the material in about 0.1 s. A somewhat similar test procedure (aatcc test method 109-1972 ansi L14, 174-1973) is used in testing colorfastness. The ozone generator is usually (but not necessarily) a mercury-vapor resonance lamp with emission lines at 184.9 and 253.7 nm. The 184.9-nm line is absorbed, and two ground-state oxygen atoms are produced ... 

Accelerated Tests. Weather resistance in an accelerated test is defined as the resistance of plastics towards changes caused by simulated open-air weathering (simulation of global radiation by means of filtered xenon arc radiation and periodic rain). After the weathering (measured by the product of intensity and duration), defined properties of the test sample are compared with those of an identical unweathered sample. Properties should be considered which are of practical importance, such as color or surface properties. For standards, see Table 1 ( Weathering in apparatus ). Apparatus test chamber, rain and air humidification equipment, air flow equipment, radiation measuring equipment. 

ISO (2004) 16000-6. Indoor Air-Part 6 Determination of Volatile Organic Compounds in Indoor and Test Chamber Air by Active Sampling on Tenax TA Sorbent, Thermal Desorption and Gas Chromatography Using MS/FID, International Organization for Standardization, Geneva, Switzerland. 

A so-called Micro Chamber (g-CTE) (see Figure 5.2) with an interior volume of approximately 45 ml has been designed by Markes Int. (Schripp et al., 2007). The X-CTE comprises six individual stainless steel cylindrical chambers (d = 4.5 cm), located in one unit. All six chambers are supplied simultaneously with the same, controlled flow of synthetic air. By reducing the chamber volume, it was intended to reduce typical emission test times but still generate meaningful emission data-i.e. results that correlate with data from conventional emissions test chambers. The g-CTE was not intended to replace standard emission test facilities. In fact it is a complementary tool intended to produce fast information about the composition and level of VOC emissions for development of new, low-emission products/materials. Micro chamber measurements have already been shown to... 

Emission test chambers, cells and analytical procedures are now standardized by ISO, ASTM and other authorities (see Table 5.1). However, it is interesting to note that only the ASTM standards take sink effects (see Section 5.3) into account Different types of testing facilities have different properties regarding amount of test specimen, dynamics, time, result and cost. In a small device the test is generally time efficient, but on the other hand sample inhomogeneities will significantly influence the results. In Figure 5.3 some trends are shown in dependency of the chamber/cell size. 

Standardized Emission Testing This is probably the most frequent application of test chambers and cells, because indoor related materials and products need to be evaluated for the release of volatile chemicals in order to ensure a healthy indoor climate. Many procedures have been established for different types of products. A very well-known scheme was developed by the German Committee for Health-related Evaluation of Building Products (AgBB) for the evaluation of building... 

ASTM WK proposed Standard Practice for Micro-Scale Test Chambers for Screening Vapor-Phase Organic Emissions from Materials/ Products ... 

ASTM (2008) WK22044 Proposed draff Standard Practice for Micro-scale test chambers for screening vapor-phase organic emissions from materials/ products. 

With the aid of emission test chamber measurements (see Chapter 5) emissions from electronic devices can be determined without any environmental influences affecting results. Such investigations aim at determining device-specific emission rates under standardized environmental conditions. Using these emission rates it is possible to make comparisons between the emission characteristics of different devices not only qualitatively (the composition of the emissions) but also quanti-... 

Test Results. The pH response of the zirconia tubes was tested at elevated temperatures and pressures using the apparatus previously described. Standard HC1 and NaOH solutions were pumped through the test chamber while the EMF of the sensor was monitored. The pH values at temperature and pressure were calculated from the room temperature pH measurement based on hydrogen ion mass balance using the data of (11). 

The value for the specific impulse is high if the reaction heat is high and produces a high flame temperature, and if the average molecular weight of the reaction products is low. Data concerning specific impulses are only comparable if they refer to the same working pressure in the combustion chamber a frequently employed standard value is 1000 Ibs/sq. in. approx. 70 bar in test chambers. 

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... 

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