Research Highlights

Technology Performance Summary: RAE Systems MultiRAE Plus for Toxic Industrial Chemicals

All Hazards Receipt Facilities (AHRFs) were developed to prescreen for chemical, radiochemical, and explosive hazards in samples collected during suspected terrorist attacks. The technologies used in AHRFs are intended to screen samples prior to a full analysis, helping protect responders, laboratory workers, and others from potential injury.

Evaluations of these technologies are summarized in the technology evaluation report, Testing of Screening Technologies for Detection of Toxic Industrial Chemicals in All Hazards Receipt Facilities. The toxic industrial chemicals (TICs) included in the report were chosen because they might be used during, or develop as a by-product from, a terrorist attack.

The screening technologies are intended:

• To be rapid and qualitative
• To be simple to use and of relatively low cost
• To indicate if samples contain hazardous chemicals of concern.

Not all of the technologies evaluated were deemed suitable for the AHRF, although they might be useful for responders on the scene.

Technology Evaluated: RAE Systems MultiRAE Plus

Sample Types Evaluated for Indication of: Hydrogen cyanide, cyanogen chloride, phosgene, arsine, chlorine, and hydrogen sulfide for vapors

Conclusions:
The RAE Systems MultiRAE Plus:

• Reliably detected hydrogen sulfide vapors (i.e., 100% accuracy).
• Failed to reliably detect cyanogen chloride and arsine.
• Failed to detect hydrogen cyanide, phosgene, and chlorine.
• Response time was approximately 15 seconds.
• Uses a relatively simple procedure.

Technology Description and Requirements: The MultiRAE Plus is a hand-held photoionization detector (PID) for volatile organics in air that can also incorporate electrochemical sensors for oxygen, explosive gases, and selected TICs. The unit tested was equipped with an electrochemical sensor for hydrogen sulfide and was challenged separately with each of the six target TICs. The PID principle of the MultiRAE Plus is not necessarily expected to respond to the TICs, but because it is promoted for use as a general toxic chemical detector, it was tested with all six TICS.

Testing Methodology and Results: Testing was conducted on one TIC at a time. The tested gases were generated by diluting a commercially obtained compressed gas standard. To evaluate the detector, a flow of clean air passed through a clean air plenum, and an equal flow of air containing the tested gas passed through another plenum: the challenge plenum. The instrument was connected to a 4-way valve, through which clean air or the tested gas flowed before being vented into a chemical laboratory hood. The technology was first exposed to the clean air flow. After this, the 4-way valve was switched to the challenge plenum to deliver the TIC gas. The sequence of exposure to clean air, followed by exposure to the TIC gas, was carried out three times in succession. This sequence was followed for each TIC and condition identified in Table 1. For this evaluation, a hydrocarbon mixture interferent was added to the blank, or TIC gas, at a ratio of 1:100 interferent mix to air flow.

Table 1: Summary of RAE Systems MultiRAE Plus Test Results

^aA hydrocarbon mixture was used as the interferent.
^bTemperature and relative humidity conditions for vapor tests were: Base = 20 °C and 50% relative humidity, Low = 10 °C and 20% relative humidity, and High = 30 °C and 80% relative humidity.
^cAEGL = Acute Exposure Guide Level and TEEL = Temporary Emergency Exposure Limit.

Contact: Eric Koglin

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