RE: Safe & Sound Wearables - Trackable Safety Helmet for Miners #2: Intrinsic Safety

mcb1 — Fri, 24 Feb 2017 06:03:13 GMT

any device which will neither generate nor store more than 1.2 volts, 0.1 amps, 25 mW or 20 μJ.

You may find that this is the energy level that is exposed to the explosive environment.

When I worked with Fuel Dispensers, many of the higher energy parts were within a special housing.

It was not airtight, but was designed to limit any internal explosion from propogating a flame to the external environment.

This meant the number of threads and sizing was designed and tested to ensure it would allow gas to escape but at a pre-ignition temperature.

In the case of the older fuel dispensers, the feed to the display was through a limiting device to reduce the energy available.

Motors were intrinsically safe with no fan and a run time of 30 mins to stop heat buildup.

I'm sure your design can use a case and you specify that a production model uses an approved design.

You may want to try to limit any wiring that passes out to a certain energy level (easily achievable nowdays).

Mark