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Recent content by jhc_jr

  1. jhc_jr

    The basics of Relative Thermal Index

    As an EE I have little background in materials properties, so I have a very basic question regarding UL 746b RTI values. Is there an aggregate value for RTI that is calculated from the three specific RTI values shown on the UL yellow card, or is the intent of the three different values on the...
  2. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    georgeverghese, Connection of a bonding/earthing device before a monitoring device is generally stipulated in most facilities as a combination of corporate policy and insurance requirements. It's also part of the recommended practice as defined in API 2003. However, as previously noted, it's...
  3. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    LittleInch, With regards to large fluid currents, it's helpful to remember that even when the mass of liquid has reach some sort of inertial stability, there is the issue of constant and significant vibration and shock being transmitted to the payload. The laboratory test parameters as...
  4. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    georgeverghese, You've hit the nail on the head - that is exactly what happens. The large ESD event damages the ground monitoring device > The ground monitoring device will not allow flow control systems to operate (fail safe) > the individual gantry becomes inoperable. Bear in mind this is a...
  5. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    We did actually consult a couple of consultants in triboelectric and precipitation static effects. One was an antenna designer and another was an aviation specialist. Neither one wanted to accept the job. One went so far as to say "The lack of definition is such that I can see so many caveats...
  6. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    LittleInch, Thanks for the reply. You're correct that there are recommended practices that should be followed. Unfortunately - as I noted in my OP - There are many cases in which these practices _aren't_ followed. In our case, there have been many instances where the bonding process was not...
  7. jhc_jr

    ElectroStatic Discharge mitigation from railcar fuel tankers

    I've been tasked with performing research on the issue of levels of ESD build up and discharge from railcar tankers before the process of petroleum transfer. Specifically, looking into a specification that our products can be tested to that would cover the connection of an electronic device to a...
  8. jhc_jr

    Radiated emissions classification

    Hi Henry, Not so much on how the device is powered, but where it taps into the electrical grid. For that matter, it isn't just radiated emissions, but also conducted emissions, as well and radiated and conducted susceptibility, and EFT. From a purely regulatory perspective, you're allowed to put...
  9. jhc_jr

    60079 "risk of mechanical danger"

    I realize this is probably a rather basic question, but I'm new to the field [glasses] 60079-0(2012+A11:2013) 26.4.2 Resistance to impact lists High and Low test criteria for Risk of Mechanical Danger. I can't seem to find anything that describes the assessment criteria for Risk of Mechanical...
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