Flexible intermediate bulk containers (FIBC), also known as a bulk bag, or big bag containers are used in many industries for storing and shipping dry products. Fertilizer, sand, pre-production plastic granules, and other mixtures of solids and fines such as Mot Type 1 mixtures used to provide a load-bearing sub-base for paved surfaces will use the strength and flexibility of FIBC bulk bags as a preferred storage and transport container.
When filling or discharging certain bulk powders in a hazardous location or anywhere the presence of flammable vapors or gases may exist, manufacturers must choose the right bulk bag to prevent an explosion or fire due to electrostatic discharge. The electrostatic properties of Type C and Type D bulk bags are effective at reducing incendiary sparks and brush discharges to the point where the propagated energy is negligent.
Safety in Hazardous Locations
Preventing and mitigating explosions in hazardous locations means removing one of three factors – the flammable substance, oxygen in the air, or an ignition source which could be an electrostatic spark from turning on a switch or an overheated surface that engages the auto-ignition temperature of a vapor or gas.
- Class I locations where flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
To accommodate hazardous locations, Type C and Type D FIBCs are used in these areas where volatile flammable gases or vapors exist under normal conditions and when those vapors or gases are normally confined within closed containers but pose a risk of accidental escape.
Electrostatic Properties of Type C and Type D FIBCs
During dry material loading or discharge, the bag containers are prone to static charge buildup. If allowed to accumulate, an electrostatic discharge could occur from the bag surface and ignite airborne flammable dust, fibers, vapors, or gases. When choosing an FIBC for hazardous locations, two options exist:
Type C FIBCs are groundable and able to conduct electrostatic discharge effectively to ground/earth when a proper ground connection is present. These bulk bags are constructed from non-conductive, polypropylene fibers that are interwoven to form a grid pattern which is then interconnected to grounding tabs to create a continuous path for the collection and discharge of electrical energy to a safe path to ground.
Type D FIBCs are static dissipative and are also referred to as antistatic bulk bags. They are commonly used to safely transport flammable powders and to prevent combustion in the presence of flammable vapors and gases. The bag surface should be protected from contamination with coatings of grease, water, or other conductive material. Type D bulk bags are constructed of a fabric manufactured to prevent the three main causes of fire or explosion-starting hazards
- Brush Discharge which can ignite the surface or liner of a standard bulk bags when a flammable atmosphere is present and can generate approximately 4mJ of energy.
- Propagating Brush Discharges can generate between 1000 – 2000mJ of energy between the surface of a bulk bags and liner, and can readily ignite flammable vapor, gas, and dust cloud atmospheres.
- Spark Discharges of ungrounded bags and their conductive parts capable of igniting gases, vapors and combustible dust.
Type D FIBCs eliminate the need for a manually connected ground because the protective fabric prevents incendiary sparks and brush discharges. Choose a CROHMIQ Static Protective Type D FIBC fabric which is engineered to provide the highest levels of protection from dissipative static electricity, and prevents sparks and brush discharge.
Both Type C and Type D bulk bags are used to transport and store flammable powders when flammable vapors or combustible dust is present. Type C bags require resistance to ground point testing and can be used to store combustible solids with MIE less than 3mJ and transporting in the presence of flammable vapors and gases with MIE greater than 0.14mJ.
Palmetto Industries is a select licensee of Crohmiq fabric tested in accordance with IEC Standard 61340-4-4 2005. With over 500,000 square feet of global warehouse space, we offer reduced lead times and expedited distribution. Don’t waste your time dealing with middlemen. At Palmetto Industries we manufacture and distribute FIBC’s, saving you time – and money. Come see what customers around the world have known for over 25 years – Palmetto is the go-to name in packaging. Call us today at 706-737-7999.