Which standards and specifications require pressure gauges to indicate the upper and lower limit ranges?
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During recent company inspections, the issues identified in each set of corrective actions were things such as inaccurate markings for the upper and lower limits on the pressure gauges, and pressure gauge readings that were not within those limits. However, the pressure at the outlet of some pumps is determined by the opening degree of the pump outlet valve, and the difference between the minimum and maximum pressures is quite large; therefore, the pressure gauge installed cannot cover all pressure levels within the 1/3 to 2/3 range. I’ve read many related posts on the forum; the answers provided in that regard are mostly based on experience or unwritten rules. Therefore, I’m looking for relevant **standards or regulations regarding safety inspections. I’m looking for a formal document that starts with GB; thank you so much! ! ! ! ! ! ! !
This post was last edited by 1111111 on 2018-5-2 16:26. What specification? ,,, Just sticking a piece of paper – is it still necessary to write it in a proper format? Regulations require everyone to memorize texts, install warning screens, as well as alarm lights and sirens – wouldn’t that be even better? . . I guess it’s the big idiot rules that require sticking notes, right? . .
This issue was discussed in this thread, but no clear conclusion was reached. If you are interested, you can take a look at the post below; there is evidence on the 5th floor, though it’s not clear whether it is valid. Pressure gauge: https://bbs.hcbbs.com/thread-1554592-1-1.html (Source: Haichuan Chemical Industry Forum)
What a strange question – what does it mean for the upper and lower limits indicated on a pressure gauge to be inaccurate? Don’t the pressure gauge scales indicate the upper and lower limits? It’s okay if it’s not exactly between 1/3 and 2/3; there shouldn’t be any issue with going beyond the range, right?
Thank you! I’ve seen this post. The person in reply on floor 5 mentioned that an upper limit should be specified, but didn’t address what proportion of the range the upper and lower limits should fall within. Does that mean it’s okay to set these limits based on the actual operating conditions of the process, without having to restrict them to the 1/3 to 2/3 range?
Our factory undergoes various safety inspections and safety audits, and during internal checks, it is required to mark the upper and lower limits at 1/3 to 2/3 using a red marker; any markings that do not fall within this range are subject to fines. . . Our pressure gauges are neither out of range nor damaged, but the pressure at the pump outlet itself varies quite significantly; it’s impossible to use a pressure gauge with a fixed range to meet such requirements. Moreover, it’s not feasible to keep replacing the pressure gauges in order to satisfy these conditions. . . I get fined every time, and this issue really troubles me. . .
Regarding the issue of marking a \"red line\" on pressure gauges for operational purposes, please refer to clause 9.2.1.2 of TSG 21-2016, Safety Technical Regulations for Fixed Pressure Vessels, which deals with the calibration of pressure gauges. Pressure gauges must be calibrated before installation; a red line should be marked on the dial to indicate the operating pressure, along with the date for the next calibration. A pressure gauge should be sealed with a lead seal after calibration.
Just found: AQ3014-2008 Technical Requirements for Safe Use of Liquid Chlorine 6.2.7 Pressure Gauges Pressure gauges should be diaphragm-type pressure gauges; if ordinary pressure gauges are used, silicone oil isolation measures must be employed. Their range should be more than twice the normal operating pressure, and they should have a calibrated maximum operating pressure mark, an expiration date indicator, as well as a seal. The calibration period for pressure gauges should not exceed six months. In addition, Clause 6.2.3 of the TSG G0001-2012 Code for Technical Inspection of Boiler Safety also contains relevant provisions.
To be precise, the upper and lower limits of a pressure gauge should not be determined by the gauge’s range, but rather by the range permitted for the operation of the equipment. For example, if the design operating pressure for a tower is 1.0 Mpa, and the lowest pressure allowed for operational purposes is 0.3 Mpa, with the pressure gauge for the tower top having a range of 0–1.6 Mpa, then the red line should indicate the range of 0.3–1.0 Mpa. This ensures that the personnel conducting on-site inspections can determine whether the tower is operating under overpressure during their inspections, thereby ensuring safety. This is my personal understanding! Of course, security management sometimes requires the deployment of specialized personnel; solely focusing on achieving results can have the opposite effect.
The “2013 Regulations on Safety Inspection of Steam Boilers” only require that a red line be marked on the dial of the pressure gauge to indicate the operating pressure.
The source should be this; generally, the work safety supervision agencies have specific requirements for inspections. dapao135 is amazing!