Are you working with dust/bulk solid/powdered products in a process facility?
Are you aware if those products are combustible/non-combustible?
In the previous article entitled “Dust explosion: an introduction”, we talked about the basic information relating to dust explosions, including how poor handling of combustible dusts could potentially lead to devastating incidents.
There is a saying, “better safe than sorry.” It is wiser to be careful and take precautions rather than regretting not doing so afterwards. In the case of working with combustible dusts, it is better to take preventive and mitigative measures to ensure a safe and secure working environment and avoid unwanted events.
One of many ways to manage the risk of combustible dusts is to understand their ignition and explosion properties by testing them so that you can avoid situations and conditions that could make those dusts explode.
There are a wide range of tests available to help you better understand the properties of your dust. However, depending on your product and process facility, some tests are more relevant while others are not. By taking the ones that are more relevant to you, you can avoid spending additional costs. The question is, which ones are they?
In this article, we will mention various tests and their purposes as well as the benefits you will get from each of the tests.
Explosibility test (yes/ no)
Purpose: To assess a product's combustion potential, this fundamental test is vital for any facility handling dust products.
Benefit: If the product tests as combustible, implement prevention and mitigation strategies to avert disasters. Further testing can refine your understanding of its ignition and explosion characteristics, ensuring accurate safety measures.
Minimum Ignition Energy test for dust cloud
Purpose: To understand the minimum electrostatic spark energy needed to initiate a dust explosion.
Benefit: Determination of the MIE helps you understand the ignition sensitivity of your product when it forms a dust cloud and especially to assess hazards due to electrostatic and mechanical sparks.
Minimum Ignition Temperature of dust clouds (MITdc)
Purpose: To determine the minimum temperature of a hot surface able to ignite a dust cloud.
Benefit: Determining the MITdc clarifies how sensitive your product is to ignition when it forms a dust cloud. This is crucial for setting the highest safe operating temperatures for electrical equipment, influencing equipment selection and monitoring protocols for machinery in dusty conditions.
Minimum Ignition Temperature of dust layers (MITdl)
Purpose: To determine the lowest temperature of a hot surface which can still ignite a dust layer.
Benefit: Determination of the MITdl helps you understand the ignition sensitivity of your product when present as a dust layer in your facility on hot equipment.
Minimum ignition temperature of dust deposits (self-ignition) (SIT/AIT)
Purpose: To determine the minimum temperature required for the self-ignition of a dust deposit as a function of the volume of the deposit.
Benefit: Test results enable predictions of self-ignition likelihood in bulk-stored dust based on initial storage temperature and delineate the onset time under conditions conducive to self-ignition, guiding storage time limitations.
Electrical resistance of dust deposits test
Purpose: To assess whether there is a possibility for so-called cone discharges in hoppers and silos after a process where the dust entering the hopper or silos may have been charged electrostatically.
Benefit: Dust resistivity measurements can determine if electrostatic charging, such as from pneumatic transport, could cause cone discharges in silos or hoppers.
Explosion pressure development
Purpose: To understand the reactivity of your dust (how fast it burns) and the maximum explosion pressure that could be generated by your dust in a closed volume.
Benefit: Test results inform the design of systems to protect dust handling equipment from explosion effects, such as venting, suppression, isolation systems, and pressure-resistant gear.
Lower Explosion Limit (LEL)
Purpose: To discover the lowest dust concentration that can be ignited.
Benefit: Understanding your dust's LEL can help maintain dust concentrations below this threshold, preventing explosions in environments with controllable dust levels.
Limiting Oxygen Concentration (LOC)
Purpose: To determine the highest oxygen concentration that can be allowed in a process where inerting is used as a measure to prevent dust explosions from occurring.
Benefit: The Limiting Oxygen Concentration (LOC) is a key reference for using inerting to prevent dust explosions and varies with the specific inert gas used to lower oxygen levels in a facility.
Dust Layer Flammability Test (DLFT)
Purpose: To determine the burning behaviour of a dust layer.
Benefit: This test result aids in evaluating fire risks where your dust is managed, including post-explosion fires that may exacerbate outcomes, enabling the implementation of appropriate countermeasures.
Still unsure which test you need? Contact us at laboratories@gexcon.com for guidance.
