Often Overlooked Powder-Handling Hazards
R&D is excited, and project engineering is ready to go. They can’t wait to manufacture a newly developed product to scale! However, there are powder-handling and powder-shipping activities, which are sometimes overlooked and can impact transportation-shipping details and facility design. What kinds of hazards could be present when powders are shipped, stored, and transferred at large-scale facilities?
Often-Overlooked Hazards
Many people know that dusts can create a flash fire or explosion when dispersed into the air and ignited. But there are other hazards that powders may inherently have, making them a risk to personnel. This includes, but is not limited to, the following:
- Dust layers can either smolder or propagate a flame
- Bulk material can undergo thermal decomposition or oxidation when subjected to elevated temperatures, such as when in dryers
- Material can chemically react with water to produce flammable or toxic gases
Not understanding these inherent hazards can result in improperly packaged dangerous goods and inadequate facility design that pose risks to personnel. Improper material characterization can also result in fines or shutting down operations, because the shipping, storage, or manufacturing operation is not following transportation or building- code requirements.
More Than Data Sheets and Shipping Papers
Several government authorities have established requirements to properly characterize the hazards of substances so that they can be properly packaged, shipped, stored, and used safely. Characterizing materials early in a product’s development and a facility’s design phase can provide information that helps identify administrative, engineering, and building controls. Helpful tests include:
- Determine if a suspended powder is explosible (GO) or non-explosible (NO-GO) when exposed to an ignition source. Depending on the outcome, a Dust Hazard Analysis may be required as well as modifying building facilities to Group H, according to building and fire codes.
- Identify if a layer can smolder or propagate a flame (UN Test N.1 burning rate) so that appropriate fire-prevention measures are selected and installed. Pay careful attention to “highly flammable” materials classified under UN Class 4, division 4.1 highly flammable solids. These characteristics can impact shipping requirements and fire-protection design.
- Establish appropriate transportation, storage, and other measures to avoid the risks presented by self-heating and pyrophoric solids by looking at results from tests like UN Test N.2 (pyrophoric solids) and N.4 (oxidative self-heating).
- Understand which (and how much) toxic or flammable gas produced for powders react with water (UN Test N.5 with request for gas characterization). This information is important when shipping in bulk (e.g., by sea) and aids in determining facility risk controls.
- Additional thermal decomposition and chemical reaction testing can help identify energetic properties, help define safe storage conditions, and provide important data for material-handling risk assessments for activities, like drying and bulk (silo) storage.
Data Is Power!
Proper characterization of material hazards can facilitate risk assessments. Common mitigation measures include the following:
- Reduce inventory, as well as segregate reactive materials in warehouses
- Adhere to building-code requirements (e.g., Group H)
- Establish strict housekeeping practices
- Design and install a fire sprinkler system and suppression equipment
- Establish safe drying and processing parameters, including installing instrumentation and interlocks
If you use or work with hazardous powders, take the time to learn more about their hazards and risks. For additional resources, take a look at the following:
Contact a DEKRA expert
today for guidance on how to test-plan to characterize your unknown hazardous materials or to review the details of your current classification information.