What is the calibration cycle for thermometers and pressure transmitters?
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Our company is a manufacturing enterprise involved in chemical processes that are subject to strict supervision. The main mixing tanks in the main production units are equipped with 3 thermometers each. Do these thermometers need to be calibrated? It has been in operation for over 2 years without any calibration being performed. Is there a specified calibration cycle or relevant standards? Is it required to calibrate pressure transmitters? Follow the product instructions? Both the thermometers and pressure transmitters are from Rosemount
For verification, calibration, and the determination of intervals, the relevant verification procedures or calibration specifications shall be followed, such as JJF 1183-2007 \"Calibration Specifications for Temperature Transmitters\", JJG882-2004 \"Verification Procedures for Pressure Transmitters\", and JJG 229-2010 \"Verification Procedures for Industrial Platinum and Copper Thermistors\".
It is required; according to GB-T 50770-2013 Code for Safety Instrumentation Design in Petrochemical Industries, clause 14.0.1 stipulates that operation and maintenance management should include operation and maintenance procedures, the responsibilities of maintenance personnel, plans and reports for regular diagnostic tests, system inspections during shutdowns, as well as the use of maintenance bypass switches and operation bypass switches.
Do you want to hire a third-party agency to carry out the calibration? Should I still follow the relevant guidelines myself?
Things like car pressure gauges, thermometers, accelerometers, etc. – once installed in the car, they aren’t calibrated anymore. They’re only replaced when they break. I’ve never seen a car explode or suffer any damage just because of these measurements. While measurement is important, it’s not necessary to pursue absolute accuracy; going too far can be detrimental...
For pressure gauges and thermometers, the fundamentals are stability; let them drift as they will – they won’t go far. Achieving an accuracy of within 1% throughout their lifetime is not difficult at all; it’s even simpler than measuring urine volume. Chemical analysis instruments, toxic gas and flammable gas detectors – in essence, their performance is completely erratic; it’s utterly unregulated and chaotic. Even if you calibrate them once a week, you probably still won’t achieve high levels of accuracy.
First, it is necessary to understand the true nature of the instrument and determine its time stability, and then proceed based on the specific purposes for which the instrument is intended and the requirements associated with those uses. Finally, consider the verification cycle.
Inspection is required, with a preferred inspection cycle of 1 year. The specific inspection time can be determined by the factory itself
To achieve **recognized traceability of measurement values, it must be carried out by a qualified testing/calibration institution; however, one can carry it out on their own if they establish the corresponding measurement standards. If it is maintenance and periodic verification, it can be done by oneself without the need to establish measurement standards.
At the moment, we only send out instruments that are subject to mandatory calibration; for those that are not subject to such mandatory calibration but for which there are suspicions of issues, we replace them with new ones. One reason is that standard instruments are too expensive (you small factories understand this), and another reason is that we have too few staff – we don’t have a team dedicated to calibrating instruments like larger companies do.
That’s indeed the case; we proceed in this way now as well