Crocs Can Ruin Your Equipment – Plus, They're Ugly
Electrostatic discharge (ESD) is a phenomenon experienced in many industries. The dangers are often forgotten but may critically affect electrically sensitive medical devices, such as pacemakers. Healthcare professionals have expressed concern over electrostatic packaging attraction issues occurring in critical care areas. One facility in Norway has banned Crocs clogs over concerns that the plastic shoes may generate static electricity that could interfere with medical equipment.
Packaging engineers can play an important role in ensuring the appropriate manufacturing, handling, packaging, and transport of electrically sensitive devices. They must consider the three important properties of packaging in relation to ESD:
- Preventing triboelectric charging
- Dissipating a charge by surface or volume conduction
- Shielding the device against electrostatic fields
Unfortunately, packaging engineers may be confused by terminology, so more education about ESD material properties may be needed. "Antistatic" refers to a material's ability to resist charge generation when rubbed against another material. "Static dissipation" refers to a material's ability to drain a charge safely away from an electrically sensitive device. A material capable of shielding an electric field has a surface resistance of less than 1x103ohm.
Such education should not be reserved for packaging engineers. End users also have an important role to play, but perhaps their education can be influenced by input at the device packaging stage. For example, the packaging of a pacemaker circuit card could provide a warning to avoid using stainless steel tweezers to pick the circuit card from its insulative tray, since metal-to-metal contact between the circuit card and tweezers could generate ESD and render the circuit card useless.
ESD validation methods for static control materials and packaging have been part of the aerospace and defence industries for decades. In recent years, the medical device and pharmaceutical sectors have begun catching up. However, the topic of ESD relating to plastic packaging of electrically sensitive medical devices is technically complex, and I refer the reader to an excellent overview by Scott Carter of Tek Pak Inc.
Vermillion, Bob. Charged Up. MedicalDevice-Network.com. Available at http://www.medicaldevice-network.com/features/feature52527/.
Jacobs, Deanna. Electrostatic discharge - understanding and controlling the phenomenon: A Handbook for packaging professionals. Available at https://ritdml.rit.edu/handle/1850/12362.
Healthcare Packaging. Health professionals express ESD concerns. Available at http://healthcarepackaging.com/applications/healthcare/health-profession....
Healthcare Packaging. ESD-safe packaging considerations for microprocessor-driven medical devices. Available at http://www.healthcarepackaging.com/applications/healthcare/esd-safe-pack....
Jane Mason, Medical Writer and Pharmacist, MPharm