TRACER GAS TESTING
Specific measurement services which LAT provides encompass:
- Building Air Infiltration and Air Leakage (ASTM Standards E741 and E779)
- Tests performed by LAT technical staff are used to evaluate building air leakage and building air tightness in large commercial, industrial and institutional buildings. LAT professionals follow ASTM Standards E741 and E779. In fact the technical principals of LAT were ASTM Task Group Chairmen during the initial development of both of these standards and as such are intimately familiar with all the experimental details required to undertake a successful testing program. The results of this testing can be used to verify building envelope performance specifications for air tightness and air infiltration.
- Building Ventilation System Performance Evaluation
- The capacity of building ventilation systems to provide outside air under various operating conditions can be measured by LAT specialists. These measurements include the total air exchange rate of a building, the total outdoor air supplied to the building, and the effectiveness of the ventilation system in removing building contaminants, as well as the discovery of building areas with inadequate ventilation air supply.
- Simulation of Contaminant Releases
- Many occurrences of contamination are episodic and, though severe when they occur, are infrequent in nature. Tracer techniques are used to simulate the migration and dispersal of a contaminant throughout a building. These methods can quantify consequences of such events and provide data useful for the avoidance of contaminant spread. Tracer techniques are also used to verify the ability of a building to contain the spread of contamination. This testing has proven especially useful in the nuclear power and semiconductor industries as well as within the US Army Chemical Weapons Demilitarization program.
- Exhaust Recirculation and Reentrainment Measurement
- Tracer techniques are used by LAT personnel to evaluate fume hood or general exhaust recirculation in a laboratory or industrial building setting. Data from these tests can be used to evaluate potentially hazardous conditions created by exhaust reentrainment or recirculation.
- Exhaust Plume Impact Studies
- Tracer techniques are commonly used to evaluate exhaust plume impact on adjacent locations. Tracer data can be analyzed on-site during a test or at a later time at the LAT facility. These data are used to generate specific reentrainment values or as input to computer models of contaminant transport in a building.
- Ventilated Enclosure Testing (SEMI Standards S2 and F15)
- Tracer gas testing of the containment performance of ventilated enclosures is required within the semiconductor chip fabrication industry. LAT scientists played a major role in providing test protocols and test data for these SEMI Standards and routinely provide these services to the semiconductor industry.
- Control Room Habitability/Personnel Safety
- In many industrial settings there are safety requirements for the control room environment during process or system upset conditions. LAT has pioneered the use of tracer gas techniques to assess unwanted leakage into control room envelopes and to evaluate control room locations for suitability as temporary safe havens. These services are routinely provided to the nuclear, petrochemical, and process chemical industries.
- Ventilation Effectiveness
- Tests can be performed by LAT to determine the effectiveness of a building ventilation system in providing outdoor ventilation air to specific locations in a building. These tests are used to detect the existence of "short circuiting" of the building supply air, to determine an overall performance index of a building ventilation system, and to assess the ability of the ventilation system to control indoor contaminant levels.
- Tracer Gas Airflow Measurement (ASTM Standard E2029)
- The constant tracer gas injection technique allows the measurement of airflows in stacks, vents, shafts, pipes, and ducts in which conventional traverse techniques are inappropriate. LAT has successfully provided tracer gas flowrate measurement services to the natural gas, petrochemical, and nuclear industries.
- Interzonal Airflow Characterization
- Tracer techniques have been used by LAT personnel to determine interzonal airflows between various parts of a building. Data from these tests are used to analyze whether specific locations within a building are capable of containing and isolating emission of various potentially hazardous contaminants. The LAT principals were Task Group Chairmen for the development of this standard. As such LAT staff is intimately familiar with the experimental details required to perform successful flow rate measurements using tracer gas techniques. In fact, LAT is approved by the Southern California Air Quality Management District (SCAQMD) to perform critical flow rate measurements using tracer gases that are required by regulation in the Greater Los Angeles Basin.Semiconductor fabrication facilities, chemical process installations and hospital isolation rooms have been studied.
