Several articles in the Type D Technology Monthly Newsletter this year have addressed explosion hazards created by processes involving flammable gases or vapours. In March, the standards that companies should be following and the legislation that companies must comply with were outlined. Terminology used in describing explosive atmospheres and the hazardous area classification that is important when assessing process risks were explained in April. The May and June editions described different types of electrostatic discharge, and explained the various elements that contribute to electrostatic ignition risk.
After initial risk assessment is completed, action plans should be developed to mitigate risks that are identified. One important risk mitigation action is to select packaging that will eliminate electrostatic discharges that can be a source of ignition. Articles in April highlighted the dangers of using the wrong type of bulk bag. An article in June explained static protective FIBC (Flexible Intermediate Bulk Container) classification, as defined in International Standards, and in National Codes and Recommended Practices. The article included an easy-to-follow guide on where each of type of bulk bag can be safely used, and where it is not safe.
There were two articles in July and August explaining explosion risks in expandable polystyrene (EPS) operations. Explosion risks created by electrostatic discharges from bulk bag packaging exist in many industries: paints and coatings, chemical manufacturing and processing, pharmaceuticals, food products, agricultural products, etc. The focus on the EPS industry is a result of our concern that some suppliers of EPS resin are using Type B FIBC for bulk bag packaging, which as explained in the above-mentioned articles is contrary to the safe practice established by official standards and regulations. Type B FIBC are only safe for use in non-combustible environments, or where the only combustible material is a powder, e.g. flour, sugar, etc. Therefore, Type B FIBC should not be used to package EPS.
Pentane is used as a blowing agent in EPS resin. As clearly stated in safety data sheets (SDS) published by EPS resin manufacturers (see August), pentane is a highly flammable gas that is at risk of ignition by electrostatic discharges. Therefore, it is incumbent upon both suppliers and processors of EPS to take all necessary preventative measures to eliminate electrostatic ignition hazards. To eliminate the risk of explosion caused by electrostatic charging and discharging of bulk packaging, it is essential for suppliers and end-users to select the correct type of static protective FIBC.
For some, electrostatics can appear complex, and making electrostatic measurements to support risk assessments can be challenging. However, deciding about safe bulk bag packaging does not need to be complex. Standards and regulatory codes are developed by teams of scientists and engineers with extensive knowledge and years of experience. Every publication is submitted to multiple peer review stages by national and international experts. The simplest way to select the correct type of static protective FIBC is to follow the guidance and requirements of standards and recommended practices (see March for official requirements, or June for a plain-language version).
To follow their risk assessments and safety guidance in their own SDS, EPS resin manufacturers supplying their products in bulk bags must “take precautions to prevent static discharges”, which means, amongst other precautions, packaging in the correct type of static protective FIBC. The correct types of FIBC for products containing flammable gases (i.e. pentane) are either Type D FIBC or Type C FIBC. However, before supplying products in Type C FIBC, suppliers must verify that their customers have the grounding infrastructure in place to securely ground Type C FIBC, which includes having process operators trained on correct grounding procedures and the critical importance of grounding every Type C FIBC. This limitation does not apply to Type D FIBC, such as CROHMIQ® Static Protective FIBC, which do not require grounding, and therefore, reduce the risk of accidents caused by human error.
Companies receiving EPS resin in bulk bags must ensure the bags are the correct type of static protective FIBC. Suppliers should be requested to package EPS resin in Type C or Type D FIBC tested and qualified to the International Electrotechnical Commission standard, IEC 61340-4-4. If the receiving facility does not have a fail-safe grounding system for bulk bags, which includes process operators being trained on correct grounding procedures, only Type D FIBC should be specified.
All FIBC complying with IEC 61340-4-4 will have yellow safety labels indicating the type of static protective FIBC (see July). It should be noted that Type B FIBC, Type C FIBC and Type D FIBC all have yellow safety labels, so it is important that process operators check the text on the label to verify it is the correct type. If Type D FIBC are specified and the yellow label indicates Type B or Type C, the bags should be quarantined and not emptied.
Whilst recent newsletter articles have focussed on the EPS industry, the information is relevant to all industries requiring static protective bulk bag packaging.