UL 1604 is obsolete and has been superceded by ANSI/ISA 12.12.01. The end of life date for 1604 was July 31, 2012. That being said, this is a good overview of the requirements for either standard. Anyone working with this type of product should also get familiar with the IEC 60079 series standards. They define the hazardous locations (known as explosive atmospheres or ATEX) requirements for europe. IEC60079-0 describes the basic requirements, and the others describe varios protection methods.
The first Tacoma Narrows Bridge was a Washington State suspension bridge that opened in 1940 and spanned the Tacoma Narrows strait of Puget Sound between Tacoma and the Kitsap Peninsula. It opened to traffic on July 1, 1940, and dramatically collapsed into Puget Sound on November 7, just four months after it opened.
Noting that we now live in an era of “confusion and ill-conceived stuff,” Ammunition design studio founder Robert Brunner, speaking at Gigaom Roadmap, said that by adding connectivity to everything and its mother, we aren't necessarily doing ourselves any favors, with many ‘things’ just fine in their unconnected state.
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