Monitoring at Chemical Agent Disposal Facilities (2005) / Chapter Skim
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4 Current Chemical Agent Monitoring Systems
4 Current Chemical Agent Monitoring Systems
Pages 21-37
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From page 21... ...
DAAMS continues to be used in this manner at the new 2003/2004 The monitoring systems currently used for the detection AEL levels. ACAMS and MINICAMS have also been used of the airborne agents GB, VX, and HD at fixed sampling to monitor airborne concentrations of agents at the limit-oflocations at stockpile disposal sites and at agent storage use concentration of 100 mg/m3 for the totally encapsulated facilities are these: demilitarization protective ensemble (DPE)
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From page 22... ...
) can cause interferences MINICAMS monitors are typically configured with an FPD (false positives)
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From page 23... ...
Howof a given monitoring system for concentrations outside the ever, the greater analytical flexibility of the A/DAM system range tested is generally considered to be uncertified. This compared with ACAMS and MINICAMS monitors may fact is important to keep in mind when using the perfor- reduce the importance of these barriers in the future, mance of monitoring systems and methods at the 1988 CDC especially when monitoring sites or operations for which 0.20 to 1.50 AEL concentration ranges to predict the numerous false positives have been experienced when using expected performance at the 2003/2004 CDC 0.50 to ACAMS or MINICAMS monitors.
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From page 24... ...
. experiences fewer false positives (interferences)
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From page 25... ...
NOTES: (1) The 1988/1997 AEL concentration ranges for GB over which MINICAMS and DAAMS have been certified and operated for many years are indicated by horizontal lines that end in arrows.
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From page 26... ...
NOTES: (1) The 1988/1997 AEL concentration ranges for VX over which ACAMS/MINICAMS and DAAMS have been certified and operated for many years at various sites are indicated by horizontal lines that end in arrows.
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From page 27... ...
NOTES: (1) The 1988 AEL concentration ranges for HD over which ACAMS/MINICAMS and DAAMS have been certified and operated for many years are indicated by horizontal lines that end in arrows.
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From page 28... ...
The Army has taken significant steps to reduce During a recent 12-month period, 8,237 primary DAAMS the level of false alarms (false positives) for ACAMS and samples were collected and analyzed at the VX GPL at MINICAMS monitors at stockpile disposal sites, especially TOCDF.
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From page 29... ...
As noted above, it may be more Finding 4-3. Air monitoring instrumentation used at stock- difficult for an operator to unlearn a skill than to learn a new pile disposal sites has been capable of reliable detection of skill unrelated to prior experience.
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From page 30... ...
It is anticiHD, which has also been monitored using DAAMS for many pated, however, that the occurrence of false positives for GB years, only relatively minor changes should be necessary GPL monitoring will increase compared with those experiwith respect to sensitivity to allow DAAMS to monitor for enced when using DAAMS to monitor at the CDC's 1988 HD at the CDC's 2004 WPL. These statements assume that VX GPL.
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From page 31... ...
of false positives is expected to increase in the following cases: There are currently no commercially available automated or manual analytical systems other than those listed above · The 2003 VX WPL, which is less than the 1988 GPL that have demonstrated the capability to meet the monitoring for this agent; requirements of the stockpile disposal program. Most agent · The 2004 HD WPL, which is less than the 1988 GPL; detection technologies currently under development are · The 2003 GB GPL level, which is one-third of the 1988 generally targeting the homeland defense market and thus GPL level; 13As a consequence of the quadratic response of the FPD, the detector 12Monitoring Technology Update, by Jeff Kiley, Monitoring Office, Risk signal for the 2004 HD GPL will be 25 times less than the detector signal Management Directorate, CMA, briefing to the committee, Chemical obtained for the 1988 HD GPL (for the same sample flow rate and sample Demilitarization Training Facility, Aberdeen Proving Ground, Md., Octo- period)
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From page 32... ...
Although cryotraps have been used to decrease eluted Although the CMA has begun to monitor at the CDC's peak widths on GC/MSD-based DAAMS confirmation sys2003/2004 WPL concentrations using DAAMS, the agency tems at stockpile disposal sites, cryotraps have not been used recently sponsored an evaluation of three automated NRT for routine DAAMS analysis by GC/FPD-based systems. A air monitoring systems for the detection of VX, GB, and HD cryotrap is generally installed so that a short length of the at WPL levels.
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From page 33... ...
. Nonetheless -- as in the case of the FPD and the halogen atoms, may result in fewer false positives compared PFPD -- the magnetically quenched FPD will not resolve with those from the FPD because there are few naturally interferences caused by phosphorus-containing compounds, occurring chlorinated compounds versus a large number of such as organophosphorus pesticides.
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From page 34... ...
Data collected on found concentrations during P&A studies may be used to determine the proper settings for alarm levels to achieve a given probability of sounding an alarm for true agent concentrations at or above 1.00 AEL, and to enable determination of false alarm rates for various true agent concentrations and various alarm-level set points. Another type of false positive is the apparent detection of agent owing to the presence of chemicals in the area being monitored that results in positive signals from the NRT monitoring system.
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From page 35... ...
method that, when equaled or exceeded, will result in The Army's latest version of its Programmatic Laboratory an audible and/or visual alarm at the location of the and Monitoring Quality Assurance Plan states that the alarm NRT monitor. The alarm level must be set so that the level for NRT monitors, which are used to monitor at STEL statistical response rate at the alarm level is greater and IDLH concentrations, can be set one of two ways (U.S.
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From page 36... ...
Although an alarm alarm levels at 1.00 and thereby reducing the probabil- level of 0.2 STEL typically ensures at least a 99 percent prob ity of detecting true agent excursions above 1.00 STEL ability of detecting a true agent excursion above 1.00 STEL, or 1.00 IDLH to 50 percent or less will be difficult to alarm levels this low contribute significantly to the frequency justify. of false alarms observed at stockpile disposal sites and con · Because some instruments may be negatively biased tribute to a reduction in worker safety caused by the human and others may be positively biased, on any given day tendency to discount an alarm if false alarms are experienced alarm rates (that is, the percentage of 1.00-AEL frequently.
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From page 37... ...
Final, June. Aberdeen Proving Ground, Md.: Chemical Within the Army Chemical Stockpile Disposal Program.
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