Definition
Automatic Continuous Air Monitoring System (ACAMS) is an audible alarming, near–real time monitor to detect chemical agents GB, VX, and HD. The ACAMS is an automated gas chromatograph (GC) that collects agent from a sampling point through a transfer line onto a solid sorbent preconcentrator tube (PCT). The collected sample is thermally desorbed into an analytical column for compound separation. The ACAMS uses a flame photometric detector (FPD) which responds to compounds containing either phosphorus (for example GB and VX) or sulfur (for example HD). Because of the low volatility of VX, a fluorinating-conditioning pad must be used at the distal end of the ACAMS sample transfer line for VX. Sample lines are heated to ensure that agent vapors do not condense in the lines before reaching the PCT. A direct readout of agent concentration, in monitoring level units, is given on the gas plasma display (GPD) of the ACAMS at the end of each sample and analysis cycle. Agent masses associated with monitoring levels are computed by the ACAMS based on daily calibration of instrument response, the sample collection time and sample flow rate through the sorbent preconcentrator tube. A strip chart recorder provides real time printouts of the ACAMS chromatogram. Audible and visual alarms are generated in the control room for ACAMS. Audible and visual alarms are also generated directly at the ACAMS station for category C and D areas, to allow unmasked workers to don protective clothing in the event of potential exposure to agent.
Definition
The DAAMS is comprised of solid sorbent DAAMS tubes, sample manifolds, sequencers, pumps, critical orifices and sample lines. Air monitoring with DAAMS employs air aspiration through the DAAMS tube for a predetermined period of time at a controlled air flow rate. Vapor sample is adsorbed on the solid sorbent. Sample lines are heated to ensure that agent vapors do not condense in the lines before reaching the DAAMS tubes. Aspirated DAAMS samples are then analyzed in the laboratory to detect agent at the various monitoring levels. The laboratory analysis uses thermal desorption of the analytes from the sorbent tubes into a gas chromatography-flame photometric detector (GC-FPD) or gas chromatography –mass selective detector/flame photometric detector (GC-MSD/FPD) analytical system. The DAAMS is used to confirm ACAMS alarms. Duplicate DAAMS sampling allows for confirmation of agent readings by analyzing samples on a dissimilar analytical column from which the original DAAMS tube was analyzed or on the GC-MSD/FPD if sufficient analyte mass is available.
Definition
The DAAMS is also used for historical monitoring. DAAMS Historical Monitoring is where the DAAMS station is not paired with an ACAMS monitor. These stations are called DAAMS-Only and are used in areas where agent is not expected.
The common stack is where multiple furnaces connect into one common stack that vents to the atmosphere. The stack is monitored using ACAMS to determine if agent is present in the gas. If agent is detected by the ACAMS, agent is automatically cut-off from being fed to the incinerators. The alarm set point and waste-feed cut-off is one-fifth of the allowable stack concentration (ASC) referenced by the Center for Disease Control in the Federal Register Vol. 53 No. 50 Tuesday, March 15, 1988 Pgs 8504-8508 . The common stack ACAMS are a staggered, co-located set of ACAMS. The offset cycle ensures the common stack is continuously sampled. For example: If the facility is monitoring GB agent the first ACAMS takes 110 seconds to sample then switches to a desorb mode to analyze the sample (70 seconds) The second ACAMS will be sampling (staggered) so that during the 70 seconds of desorb and analysis time the stack is sampled by the second ACAMS. A waste-feed cutoff is in place if the ACAMS are outside of the range of 90-110 seconds indicating the ACAMS are not in staggered mode. A third (backup) ACAMS has been calibrated/challenged with the primary ACAMS and is able to be placed on line at any time. DAAMS tubes are continuously sampling the stack gas emissions. If an ACAMS alarms the DAAMS are pulled and analyzed to determine if agent was actually present. DAAMS detection capability allows for agent confirmation from a single ACAMS alarm cycle.
The furnace duct is monitored using one ACAMS with a corresponding DAAMS station. If a duct ACAMS alarms, an automatic waste feed cut-off is initialized to that furnace. DAAMS tubes are pulled and analyzed as discussed for the common stack.
Carbon filtration systems are used to ensure containment of airborne contamination within the toxic enclosures. There are nine carbon units with six banks of carbon in each unit. To determine when the carbon is spent or agent is getting past a carbon bank, an ACAMS is used to monitor the carbon filtration system between the first and second; the second and third; and the third and fourth activated carbon filter elements and in the HVAC stack. DAAMS monitoring is required at all collocated ACAMS stations. Corrective action to change the filters is initiated, once the presence of agent is confirmed between the second and third midbed.
Plant area monitoring falls into one of two general categories. Safety Monitoring and Process Monitoring. Safety monitoring is conducted at the Time Weighted Average (TWA) level to protect unmasked workers. Process Monitoring is performed to provide information for operations and maintenance tasks, and to assess the state of contamination of equipment or waste in Toxic Maintenance processing, and to assure PPE is decontaminated prior to personnel departing toxic areas into clean areas. Process monitoring may be conducted at any level from Time Weighted Average (TWA) to Maximum Permissible Level (MPL) depending on the level of contamination to be monitored. Category C areas are nontoxic work areas adjacent to Category A and B areas. Low level vapor agent contamination is possible is these areas so they are monitored with a ACAMS/DAAMS station. Category D is an area considered to be uncontaminated and Category E is positive pressure filtered air areas where agent should not be present. Areas D and E are monitored using DAAMS only for historical purposes.
The installation perimeter is monitored by DAAMS at the General Population Level (GPL) Federal Register Vol. 53 No. 50 Tuesday, March 15, 1988 Pgs 8504-8508 The purpose of the perimeter monitoring DAAMS station is not to control disposal activities or to provide an early warning of an accidental release; rather they are used to record if agent was detected outside the Chemical Demilitarization Facility boundaries. The locations for monitoring were chosen based on site-specific conditions (meteorological conditions, location of critical receptors, site boundaries, topography, etc.) In general, 10 of these stations surround the TOCDF.
If you would like more detailed information or have questions please contact:
Martin Gray
DEQ / DSHW
P.O. Box 144880
288 North 1460 West
Salt Lake City, UT 84114-4880
Telephone: 801-538-6170
Facsimile: 801-538-6715
E-Mail: martygray@utah.gov
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