The 2019 edition of the NFPA static electricity recommended practice, NFPA 77-2019: Recommended Practice on Static Electricity, 2019 edition has been released.
When we think of electricity coursing through the air, our minds often conjure the image of a lightning bolt. Lightning that emerges in the clouds and strikes the ground is an extraordinary power—lightning bolts travel towards the Earth at 200,000 mph, are 5 times hotter than the sun’s surface, and can contain up to one billion volts of electricity. Plus, lightning is an example of a static electric discharge.
However, this association may give a more ferocious view of static electricity. Lighting kills over 2,000 people worldwide annually, but direct exposure to most static electric discharges are often far more innocuous. In general, a static electric discharge (or electrostatic discharge) is just a release of static energy due to an imbalance of electrical charges within or on the surface of a material. According to NFPA 77-2019, it can be in the form of a “spark, corona discharge, brush discharge, bulking brush discharge, or propagating brush discharge.” More often than not, efforts to mitigate static electric discharges are intended to protect computer components and other materials sensitive to static electricity.
However, this burst of energy, while often presenting minimal direct harm to human life (often, but not always), can be the spark needed to ignite flammable atmospheres containing flammable or combustible gases, vapors, dust clouds, or other materials under certain circumstances.
Unsurprisingly, these explosions or conflagrations can be disastrous, leading to severe property destruction, injury, and even death. For example, in November 2017, static electricity ignited an explosion at a cosmetic factory in upstate New York that claimed the life of one person and put another 125 people in the hospital.
Since it applies to the identification, assessment, and control of static electricity, NFPA 77-2019 is used to prevent fires and explosions. While it does not apply to shock hazards from static electricity, the application of principles set forth in the recommended practice can reduce shock hazards to personnel.
NFPA 77-2019 assists its users in controlling hazards associated with the generation, accumulation, and discharge of static electricity. The document meets this goal by providing basic understanding of static electricity, guidelines for identifying and assessing static electricity hazards, techniques for controlling static electricity hazards, and guidelines for controlling static electricity in selected industrial applications.
As a revision of the 2007 edition of the same standard, NFPA 77-2019 has undergone some changes. In addition to updating its reference documents and some editorial changes for better alignment to Manual of Style for NFPA Technical Committee Documents requirements, NFPA 77-2019 contains alterations to the definitions for combustible dust and grounding. Furthermore, to better reflect accepted international standards, there are changes to the characterization of low, medium, and high resistivity powders in Chapter 15, “Powders and dusts.”
Users should note that NFPA 77-2019 does not apply to stray electrical currents, induced currents from radio frequency (RF) energy, cleanrooms, lighting, or the fueling of motor vehicles, marine craft, or aircraft. It also cannot be used to control static electricity in relation to electronic components or circuits. These are instead covered by their own standards, which are often addressed by the Electrostatic Discharge Association.
NFPA 77-2019: Recommended Practice on Static Electricity, 2019 edition is available on the ANSI Webstore.