This part of ISO provides a selection of suitable test methods from those available for the measurement of contamination gases in compressed air. The applicable ISO standards you may use to benchmark your equipment’s .. ISO specifies the test method for gaseous contaminant content. Find the most up-to-date version of ISO at Engineering
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The method for collecting the sample is similar to the membrane method, except that the weight of the membrane must be recorded prior to use and then re-weighed after collection of the sample.
Samples are analyzed using an optical microscope. The primary analytical method is by gas chromatography for vapor content in the range of 0. They include condensation nucleus counting, differential mobility analysis, and scanning mobility particle sizing. Avoid the potential for leaks by limiting elbows, tees, and valves. It may be beneficial to use high-purity valves and fittings along with the sampling set up to ensure compliance with low particle requirements, such as class 1.
Additionally, samples can be held indefinitely for re-analysis by microscopy or other more specific techniques.
This enables easy cleaning in between multiple samples. Particle testing is performed by size or by mass, depending on the selected purity class. Chemical indicator tubes can be used only as a preliminary method they lack the sensitivity and specificity required for quantitation at low levels. All other purity classes require 1, liters or less of air volume and only 12 minutes or less for sampling time. No particle size or quantity is determined. After sampling, the membranes are weighed, extracted with n-pentane, and re-weighed.
ISO consists of nine parts or sections that address compressed air. There are no established ISO purity classes or limits for these other gases.
We have had customers identify particle contamination sources as O-rings in valves and filter housings, flexible tubing, distribution piping, and plastic or metal fittings. Lighter hydrocarbons composed of five or less carbon atoms are not included in total oil purity classes.
Once again, the sampling procedure calls for a sampling probe, this time being installed into a stainless steel extraction tube filled with coconut charcoal. Other purity classes require liters of air or less.
GSO ISO – Standards Store – GCC Standardization Organization
Because the LPC can be used to sample multiple locations rapidly with on-site test results, it is an excellent troubleshooting device. Full flow sampling can iao used with this type of sampling equipment. Purchase More information add to basket. These tubes possess the advantages of being less expensive and having a more reliably low level of contamination than laboratory-prepared tubes.
ISO – Compressed air — Part 6: Test methods for gaseous contaminant content
Particles can also be sampled by using a gridded membrane in a suitable holder and analyzed using an optical microscope. A color change or chemical reaction will occur between the water vapor in the air sample and the chemicals in the tube. To prevent the interference of ambient moisture permeating into the compressed air sample stream, select impermeable materials, such as polished stainless steel or PTFE.
The membrane in this case protects the charcoal tube from aerosol contamination. This assures that the sampler is operating correctly prior to sampling compressed air outlets. The connection between the point of use and the sampling equipment should be short, straight, and made of stainless steel without elbows, tees, valves or dead ends.
A slight amount of hydrocarbon contamination in a fitting is enough to produce unacceptably high levels of oil vapor OV on the charcoal tube. It is quite common for air compressor systems to have a permanent, fixed-mount hygrometer that can provide the dew point at various points throughout a system. Code s Theme s Be aware that the use of quick disconnect fittings, valves, gauges or anything with O-rings can lead to sporadic particulate contamination.
Normal sampling times vary between 2. Fite Date of publication: Both techniques are intended for oil contamination levels between 0. Other hygrometers are better suited for in-laboratory use—either due to expense or lack of portability.
Sampling and Testing for Compressed Air Contaminants
In addition, they may not provide results in terms that are readily converted to the sio employed by the standard. In some cases, useful information can be determined about the type of particles present. Typical testing time is between io and hours. The maximum allowable number of particles per cubic meter varies by purity class. Certification of persons Do recognize your skills, register online to become certified. Methods listed are in preferred order.
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