The future role of the humble paper clip in Hazardous Areas
Apart from their traditional use of holding the multiple sheets of paper that one is required to have with them when performing inspections on equipment in hazardous areas, what are the other uses for the humble paper clip these days ?
The first one that came to mind was a piece of test equipment for IS switch circuits. Chris Towle has always suggested the use of a straightened out paper clip to fault find cabling or other faults on switches connected to IS interfaces. Acting as a simple shunt and being classed as Simple Apparatus, it can be used at convenient points along the loop starting at the Hazardous Area terminals of the interface to see at what point the problem occurs.
A second use came to an end this week with the release of the OSHA Directive on Dusts (link). Previously NFPA654 (Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids ) has used 1/16″ or the thickness of our favourite tool, as being the sufficent depth of dust required on a piece of equipment for it to be considered to be posing a significant risk of flame spread or secondary explosions. The recent OSHA document has now reduced this to be 1/32″ based on recent tests. This is of course a rule of thumb and the actual thickness will depend on other factors but it has reduced the applications for our paper clip. We therefore need you to come up with other uses, suggestions please via the comments section.
Steve
PS The good news is that the OSHA Directive does suggest the use of Intrinsic Safety as the protection technique to be used for instrumentation in areas where there are dust hazards so not everything is that bad. Perhaps this will finally increase the use of the technique in North America
December 9, 2007 at 3:10 pm
This is a very important safety measure, as we know that OSHA is a legal requirement for USA, beyond a simply technical one.
Regarding the OSHA “permitted installations”: 1) intrinsically safe, 2) approved for the hazardous (classified) location, or 3) safe for the hazardous (classified) location, please, note that it is not allowed to consider “the consequences of an explosion” to install equipment with a “lower safety degree” of those required by American standards.
Comparing with the IEC EPL method, where a “lower EPL than required” is allowed if “the consequences of the explosion” are “small”, we can say that OSHA method is safer.
The EPL method sounds as a “black hole”, where all installation’s “non-conformities” can “disappear” with a snap, simply saying that “the consequence of an explosion is low”.
How may deaths can be considered as “low consequence” of an explosion?
This “EPL” seems to be against all safe requirements given by IEC Ex standards.