Mahn Face velocity was measured times using a thermal anemometer TA-2 model. UC Lab Safety Workgroup. Chemical Health and Safety. Application of non-dispersive infrared NDIR spectroscopy to the measurement of atmospheric trace gases. Hitchings DT, Maupins K. Taylor S, Initiative TC.
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Its history dates back to , making it trusted as one of the premier sources for standards, operating practices, research and more within the industry. Their standards create defined minimum values for accepted performance of a variety of ventilation-related products. Essentially, it outlines a quantitative test procedure for determining the operating capabilities, such as containing and exhausting fumes, of a fume hood.
This is due to the large number of variables in hood environment e. It is used not only by manufacturers during development and design, but also as an informal criteria for purchasing a fume hood for many labs, and as a method of performance evaluation and certification for fume hoods being installed. There are three key areas of the standard: face velocity measurement, smoke visualization, and tracer gas containment.
The face velocity measurement requires multiple point readings to determine the average face velocity the fume hood can maintain. It also includes measurement of cross drafts around the hood and calibration of airflow monitors. In addition to airflow patterns, the smoke test shows turbulence at the front of the hood caused by the room environment. It can also show how conaminants could escape from the hood, if it is leaking, and reach the operator at various sash heights.
The latter two are optional. Three of these tests are done. Each one lasts five minutes and uses four liters per minute of SF6. Labconco uses analyzers that measure to 0. The use of SF6 is important due to its uniqueness. It also behaves consistently so the same test can be run multiple times to reliably get the same result. These unique attributes help to avoid false readings during the test. AM is done once the hood is built and is generally done in a testing lab where environmental factors are removed as much as possible.
AI testing is done once the hood is installed in the lab but before anything is placed inside. Finally, AU testing is done in the lab with materials beakers, equipment, etc. This test takes into account both the room environment and users, and can determine if there is an issue with how it is being operated by comparing the test results to the AI results. Each lab sets its own acceptable levels for the test results.
In addition, some organizations, such as the Scientific Equipment and Furniture Association SEFA provide ratings for acceptable concentration levels of each test. For example, SEFA requires a hood to have an average containment loss of 0. The latest version includes changes regarding the mannequin height and data collection. The test procedure itself was modified based on committee experience and to clarify statements from the edition, such as the breathing zone height.
He explained the major changes of this update. This was based on research suggesting that the average height of fume hood operators has decreased over the past decade. Gilkison shared this change is particularly important because it creates a more accurate test and therefore can lead to a safer work environment for the operator.
Another key component of the update is that it requires digital collection of data during testing procedures rather than manual data collection. This was previously recommended, but not required. According to Gilkison, this reduces the chance of human error in recording this data. The information-based sections were also significantly lengthened, including expansion of Appendix A and a new, non-mandatory Appendix B that provides guidance on investigating poor fume hood performance.
What is ASHRAE 110-2016?
Ketaxe The concentration of tracer gases was measured using direct reading instruments. A considerable amount of sulfur hexafluoride is applied to evaluate the performance of each laboratory hood according to ASHRAE— method. Appl Occup Environ Hyg ; 15 2: In this test, sulfur hexafluoride SF6 is applied as a tracer gas to quantitatively evaluate the performance of laboratory hoods. The application of ASHRAE hood performance test with smaller volume of tracer sulfur hexafluoride gas is not recommended.
ASHRAE 110-95 PDF