Explosive Material Hazards
Fire Technology Services

image: Propagation of ignition through the 5-L explosibility chamber

Propagation of ignition through the 5-L explosibility chamber

image: Dust cloud explosion inside Hartmann explosibility apparatus

Dust cloud explosion inside Hartmann explosibility apparatus

image: Catastrophic failure of a compressed hydrogen cylinder installed on a vehicle

Catastrophic failure of a compressed hydrogen cylinder installed on a vehicle

image: Infrared view of compressed hydrogen cylinder failure

Infrared view of compressed hydrogen cylinder failure

A full range of experimental and analytical services to evaluate explosive material hazards is offered by Southwest Research Institute (SwRI). Resources include large- and small-scale fire research facilities, explosive and propellant test ranges, vapor and dust explosion facilities, and computer modeling software.

Gas & Vapor Explosibility Characterization

SwRI has the ability to determine the relationships among fuel, oxidants, diluents, temperature, and pressure with respect to ignitibility. Triangular flammability diagrams can be developed for various temperatures and pressures that graphically depict regions of danger and safety. Ignition tests can be performed over regions of flammability to determine the energy required to initiate combustion. Data can be used for Material Safety Data Sheets (MSDS) or to improve the safety of chemical processes. Standard test procedures include:

  • Various ASTM flash point tests
  • ASTM E1232

    Temperature Limit of Flammability
  • ASTM E681

    Concentration Limits of Flammability of Chemicals (Vapors and Gases)
  • ASTM E918

    Limits of Flammability of Chemicals at Elevated Temperature and Pressure
  • ASTM E2079

    Limiting Oxygen (Oxidant) Concentration in Gases and Vapors
  • ASTM E582

    Minimum Ignition Energy and Quenching Distance in Gaseous Mixtures
  • ASTM G125

    Liquid and Solid Material Fire Limits in Gaseous Oxidants
  • ASTM E 659

    Autoignition Temperature of Liquid Chemicals
  • ASTM G 72

    Autogenous Ignition in a High-Pressure Oxygen-Enriched Environment

Dust Explosion Hazards

Dust cloud explosion inside Hartmann explosibility apparatus

An apparently inert solid can produce extreme hazards when in a powder or dust form due to the ease of its dispersion in air. SwRI is experienced in characterizing dusts for their explosion potential with several test methods:

  • ASTM E789

    Dust Explosions in a 1.2-Liter Closed Cylindrical Vessel
  • ASTM E1515

    Minimum Explosive Concentration of Combustible Dusts
  • ASTM E1226

    Pressure and Rate of Pressure Rise for Combustible Dusts
  • ASTM E2019

    Minimum Ignition Energy of a Dust Cloud in Air
  • ASTM E1491

    Minimum Autoignition Temperature of Dust Clouds
  • ASTM E2021

    Hot Surface Ignition Temperature of Dust Layers

Blast Effects and Explosion Mitigation

SwRI has extensive facilities for simulation and measurements of small- to large-scale fires, blasts, and explosions. SwRI’s remote test site allows the safe simulation of explosions too severe to perform on the main grounds. Blasts can be measured and viewed with an extensive array of equipment:

  • High-speed blast pressures and sound levels
  • High-speed color video
  • Infrared and ultraviolet imaging
  • High-speed strain and acceleration
  • Sonic velocity jet-fire apparatus

Explosion Mitigation

Once fire and explosion hazards have been adequately characterized, steps must be taken to reduce the likelihood of catastrophic event. The following services are available:

  • Active and passive fire protection material design and testing
  • Deflagration and detonation flame arrester evaluations
  • Explosion venting modeling and testing
  • Passive and reactive armor testing

Hazardous Material Storage & Transportation

Testing is performed in accordance with the United Nations’ Recommendations on the Transport of Dangerous Goods — Manual of Tests and Criteria. Testing includes classification for:

  • Explosives (Class 1)
  • Flammable liquids (Class 3)
  • Flammable/self-heating solids (Class 4)
  • Oxidizing substances (Class 5)
  • Ammonium nitrate fertilizers (Class 9)

Additional testing includes evaluations of:

  • Self-accelerating decomposition temperatures
  • Deflagration/detonation propagation
  • Deflagration/detonation inside packaging
  • Heating and explosions under confinement
  • Explosive power

Related Terminology

code compliance  •  engineering design  •  fire and explosion investigations  •  fire resistance  •  fire testing laboratory  •  material flammability  •  product development  •  risk and hazards  •  suppression  •  third party certification

Benefiting government, industry and the public through innovative science and technology
Southwest Research Institute® (SwRI®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 9 technical divisions.