Man in Simulant Testing (SST/MIST)

Man In Simulant Testing (MIST) is the preferred method of determining the overall Protection Factor (PF) of Chemical, Biological, Radiological and Nuclear protection equipment to be used for protection against chemical warfare agents (CWA). The results are used with the Body Region Hazard Analysis (BRHA) to determine the overall PF of the suit and the Medium Required Exposure Dosage (MRED).

How is MIST performed?

  • Dressing test participants in a protective suit ensemble with passive sampling devices (PSDs) placed on the skin
  • Exposing the test participant to a high concentration of a non-toxic CWA simulant while performing routine exercise movements
  • Removing and analyzing the PSDs for simulant vapor that was adsorbed on the skin
  • Analyzing the PSD data with the BRHA to determine performance characteristics of the suit ensemble
  • Obtaining data through analysis at the lab

Capabilities

  • Determine the overall protection factor of a suit ensemble
  • Calculate the MRED for nerve and blister agents
  • Temperature control

Equipment

  • Test Chamber : 40’ L x 20’ W x 14’ H
  • Four one quarter horsepower industrial fans
  • Five-stage clean room with overpressure
  • 600 cfm fan filter assembly to create overpressure
  • Challenge Generator
  • Hot-air vapor generator blower system
  • MIRAN®

The System Simulants Test Team within the Test Reliability & Evaluation Branch (TREB) operates two static challenge test chambers. The chambers provide a controlled environment for static challenge, entry/exit, and pressurization testing of Chemical, Biological, Radiological, and Nuclear (CBRN) protection equipment. These chambers have a long history of use for full Collective Protection (CP) testing of tracked and wheeled vehicles, hard and soft walled shelters, and even field deployable environmental control units.

Once an item is set up in the chamber, a pressurization test is performed to ensure the item maintains proper overpressure. The test item would then be exposed to static challenge trials to determine its protection factor, and an entry/exit test would be performed to determine the maximum number of people that could be processed into a shelter or vehicle within an hour.

Purge testing is also conducted in the chambers to help determine how long it takes for an airlock, shelter, or vehicle to clear itself of a particulate cloud.

Leakage testing is another type of test performed on a vehicle or shelter to identify and correct possible leakage points. The Improved Mobile Airflow Tester (IMAT) is used to isolate and quantify airflow leakage rates at various system operating pressures on vehicles, and shelters.

The mid-size, 39’ L x 20’ W x 14’, chamber uses a hot air vapor generator and industrial standard mixing fans to produce a Methyl Salicylate (MeS) vapor concentration of up to 100 mg/m3 vapor.

A MIRAN® in conjunction with a concentration controller and a Data Acquisition System are used to automatically monitor, maintain and record test parameters/data. Air sampling is performed with MINICAMS® and sorbent sampling tubes filled with Tenax TA.

The large scale Static Challenge Test Chamber (46’L x 29’W x 14’H) is outfitted with a data acquisition system, vapor generator, MINICAMS®, and instrumentation, and is used for testing larger CBRN equipped systems.

Capabilities

  • Air Flow: 0 – 5000 CFM-
  • Simulant Concentration: 1-100 mg/m3
  • Dimensions: 39’ L x 20’ W x 14’ H-Mid-size chamber
  • Dimensions: 46’L x 29’W x 14’H-Large scale chamber
  • Temperature control
  • Static Challenge Testing
  • Entry/Exit Testing
  • Pressurization Testing
  • Purge Testing
  • Leakage Testing

Air Samplers

  • Stainless steel sorbent sampling tubes
  • Vacuum pump with inline critical orifice
  • Electric actuated sequencer
  • MINICAMS®
  • Challenge Generator
  • Hot-air vapor generator blower system
  • Foxboro miniature infra-red gas analyzer (MIRAN®)