What makes a device intrinsically safe

If you're looking for intrinsically safe devices, you're probably already aware of the situations and scenarios in which these devices are required. But for those that aren't, there are many volatile workplaces have the requirement for devices operating in the field to be intrinsically safe. These include gas refineries, mines, military, farms, plants, and many other situations that have the potential for gases, powders, and flammable liquids to be ignited. Combustion fire requires a fuel source, oxygen, and an ignition source.

In environments such as gas refineries, there are often flammable gas vapours, or powders and dust in the air along with oxygen, creating an environment where an ignition source is all that's required.

This is to identify any damage, deterioration or unapproved replacement of IS components. While IS equipment can in some cases serve as a replacement for explosion-proof equipment, that is not always the case. This is due to the reliance on low power and temperatures. Editor's Note: This article was originally published in March and was recently updated.

Stay up to date with news as well as educate yourself with electronic contract manufacturing resources. May 20, Tweet. Common industrial equipment like motor brushes and switches are at risk of: Internal sparks Overheating Short-circuiting By simplifying the circuitry, controlling internal temperatures, and adjusting components to reduce dust-caused shorts, this equipment protects workers from a variety of threats. How Does It Work? Which Electronics Apply?

Intrinsically Safe Vs. Explosion-Proof Explosion-proof products are capable of containing an explosion inside an enclosure. A good starting point for meeting intrinsically safe guidelines is to first check and make sure the product also meets RoHs compliance standards and IPC standards.

If an unsafe PCB is used in a hazardous environment, gases, fibers, fillings, vapors and dust in the air may ignite, potentially leading to explosions, injuries, and deaths. In all of these environments and more, unsafe PCBs can cause catastrophic accidents. Abiding by intrinsically safe design guidelines will lessen workplace danger. There are many things that engineers can proactively do to comply with intrinsic safety standards and improve the safety of their designs.

Below are a few methods that electronics OEMs use to ensure their products are safe. Try splitting the power in a device into multiple circuits. This enables the electronics manufacturer to maximize the amount of power in an electrical device without putting too much power in a single circuit.

Enhanced voltage levels must be protected with voltage limiters. If not, the PCB may spark, running the risk of ignition. When choosing batteries, like high-density, lithium-ion batteries, make sure they can withstand the conditions of their end-use environment.

In addition, it's important to minimize the electrolyte leakage that occurs when a severe short-circuit occurs. Intrinsic safety is one approach to assuring safety limiting the energy the device can possibly release to guarantee no ignition for a specific class of hazard. Intrinsic safety limits can be exceeded by the presence of a small capacitor, long wires etc.

That can be extremely restrictive in terms of what is permitted, but it can allow wiring from non-intrinsically safe devices such as computers to sensors placed in hazardous areas to be placed in the open, provided they are passed through an approved for the class of hazard intrinsic safety barrier- a very reliable redundant terminal strip block type of device that will never let dangerous energy through, so unless the devices on the other side of the barrier do something prohibited like store more than a tiny amount of energy they are intrinsically safe.

A practical example of this might be a thermocouple connected through a barrier to a computer in a control room. Even if the computer fails and puts VAC on the thermocouple inputs relative to ground, the barrier will prevent that from getting to the hazardous location methods used are redundant Zeners, fuses, series impedance etc.

Another approach is to put the device into an approved for the type of hazard explosion-proof housing. Such a housing is designed to not rupture if the gas inside explodes to contain the explosion , and to only release gases that are sufficiently cooled so that it will not act as an ignition source itself.