Further Testing in Dust Hazard Analysis

Combustible Dust Roadmap

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Understanding DHA Terminology

Testing your plant or manufacturing facility for possible hazardous dust or combustible dust will seem perplexing until you understand simple terminology outlined by OSHA, NFPA and other regulating authorities. See the names of the tests, their purpose and definitions below.

Risk Analysis of Hazardous Dust

When developing mitigation strategies for potentially hazardous, explosive or combustible dusts, it is important to characterize the hazard risk of the material in question by determining its explosion severity and ignition sensitivity. 

Explosion severity data will determine if an explosion hazard exists and, if so, how energetic it may be while ignition sensitivity data will assess the probability of risk based on how the material responds to heat, spark, impact and frictional forces.

Air Separation Technologies, Inc. offers the following NFPA Combustible Dust Hazard Assessment (DHA) testing and services for determination of both explosion severity and ignition sensitivity per ASTM and European EN methods:

 

Explosion Severity Test - (KSt ,PMax and dP/dtMax)

ASTME 1226 – 2010 - Determines values necessary for designing protective measures, such as deflagration venting

EN14034 - Part 1:2004 - Determination of the Maximum Explosion Pressure (Pmax) of Dust Clouds – Part 2:2006 - Determination of the Maximum Rate of Explosion Pressure Rise (dP/dtMax ) of Dust Clouds

 

Minimum Ignition Energy - (MIE)

ASTM E2019 - Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air

EN13821:2002 - Potentially Explosive Atmospheres - Explosive Prevention and Protection - Determination of Minimum Ignition Energy of Dust/Air Mixtures

 

Minimum Explosible Concentration - (MEC)

ASTM E1515 - Identifies the Minimum Hazardous Concentration of a Dust Cloud that will Sustain Combustion

EN14034-3:2006 - Determination of Explosion Characteristics of Dust Clouds - Part 3: Determination of the Lower Explosion Limit (LEL) of Dust Clouds

 

Minimum Autoignition Temperature of a Dust Cloud - (MIT)

ASTM E1491 - Determines Safe Operating Temperatures at Which a Dust Cloud Will Not Autoignite

EN50281-2-1:1999 - Electrical Apparatus for Use in the Presence of Combustible Dust - Part 2-1: Test Methods - Methods for Determining the Minimum Ignition Temperatures of Dust

 

Hot Surface Ignition Temperature of Dust Layers - (LIT)

ASTM E2021 - Identifies Dangerous Operating Temperatures at Which a Dust Layer Will Self-Heat

EN50281-2:1999 - Electrical Apparatus for Use in the Presence of Combustible Dust - Part 2-1: Test Methods - Methods for Determining the Minimum Ignition Temperatures of Dust

 

Limiting Oxygen Concentration - (LOC)

Defines Safe Nitrogen Inerting Levels to Prevent Dust Cloud Explosion

EN14034-4:2004 - Determination of Explosion Characteristics of Dust Clouds - Part 4: Determination of the Limiting Oxygen Concentration LOC of Dust Clouds