I would like to ask about on-site grounding, mandatory inspection of pressure gauges, and other related issues
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Dear teachers, after a group of experts visited our factory for an inspection, they suggested some actions for improvement, and I would like to seek your advice on some of them. As follows: 1. Experts: The explosion-proof junction box on site had incomplete bolts on its enclosure, and the enclosure was not grounded. It’s definitely our mistake that the bolts are not complete; we will correct it immediately. However, the signal box located inside the JB box operates at a voltage of only 24VDC. I remember that field instrument equipment with a voltage not exceeding 36V does not require protective grounding. Also, since the JB boxes are all installed on steel structures, I think grounding is unnecessary. Q: Is everyone grounding their JB boxes? 2. Expert: There is a lack of static discharge bonds on the pipeline. First of all, the pipeline is made of 316L material, without a fluorine-lined interior. The pipeline flange is connected to the on-off valve. 4 bolts have been connected; is an electrostatic bridge still needed? According to the specifications, a bypass connection is required if there are less than 5 connecting bolts, or if the resistance is greater than 0.03 ohms. Q: Do you have jumper wires at all the pipe connections? 3. Experts: All pressure gauges must undergo mandatory inspection. Gauge pressure meters that include electrical contacts provided by the equipment – there are over 1,000 such gauges throughout the plant; I need to take them apart and send them to a calibration institute for inspection, and then reinstall them on site. The amount of work. . . We are now submitting the pressure gauges on pressure vessels and pressure pipelines for inspection as Category A items. The remaining tables are classified as Category B; during parking for maintenance, qualified construction teams shall carry out pressure testing on each one and attach a certificate of verification. Q: How do you do it? Thank you all! ! ! ! ! ! !
I’ve encountered this situation too and feel the same way.
1. The enclosure of the on-site wiring box must be grounded; 2. It is more reliable to use static discharge bonds on the pipelines. 3. Pressure instruments should be calibrated before installation, and this calibration can be done individually for each instrument or through random sampling.
1. It must be grounded; otherwise, experts will criticize it. 2. There are standards and classifications for static electricity across pipelines, and some of these requirements aren’t met – experts say so, and then more criticism follows. 3. The factory should establish a standard measurement laboratory and label things itself
1. According to the specifications, wiring boxes operating at 36V or higher must be grounded; for those operating below 36V, no explicit requirement is given, but since experts have recommended it, it’s still a good idea to provide grounding. 2. For the jumpers on the pipeline, follow the standards – ignore them. 3. Ignore him outright; the Safety Supervision Bureau will specify which pressure gauges require mandatory inspection