Regulations regarding the calibration of pressure gauges and their calibration intervals

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As a measuring instrument, pressure gauges are primarily used for safety protection, industrial process control, as well as the monitoring of pressure levels. It is crucial for the proper operation of equipment and facilities that pressure gauges display accurate readings; therefore, it is necessary to perform regular inspections on them. Currently, the common practice among companies is to conduct an inspection of all pressure gauges once a year, while some companies with stronger financial resources carry out inspections every six months. Some safety inspection officers also hold the view that \"all pressure gauges must be inspected once a year or every six months,\" and they order companies to make corrections within a specified time frame for those pressure gauges that have not been inspected regularly. So, must all pressure gauges be subject to mandatory regular calibration? What is the frequency of such calibration? How should issues related to untreated pressure gauges be addressed? From the perspective of work safety law enforcement and supervision, this article explores matters related to pressure gauge calibration by referring to laws, regulations, rules, and regulatory documents, in order to provide a solid legal basis for safety supervision efforts and thus avoid unnecessary administrative reviews and lawsuits. I. Scope of mandatory calibration for pressure gauges Pressure gauges are considered measuring instruments, and the requirement for mandatory calibration of such instruments stems from the Measurement Law of the People’s Republic of China, which was issued on September 6, 1985. Article 9, Paragraph 1 of this law stipulates that the metrology administrative departments of people’s governments at or above the county level shall enforce mandatory inspection on social public metrological standard instruments, the highest-level metrological standard instruments used by departments, enterprises, and institutions, as well as working metrological instruments listed in the mandatory inspection catalog that are used for trade settlement, safety protection, medical and health care, and environmental monitoring. It shall not be used if it has not been submitted for inspection as required or has failed the inspection. The catalog and management measures for work measuring instruments subject to mandatory verification shall be formulated by the State Council. The \"Administrative Measures for the Calibration of Working Measuring Instruments Subject to Mandatory Calibration in the People’s Republic of China\", issued by the State Council on April 15, 1987, and the \"Detailed List of Working Measuring Instruments Subject to Mandatory Calibration in the People’s Republic of China\", issued by the Bureau of Metrology on May 28, 1987, both stipulate that pressure gauges used in trade settlements, safety protection, medical and health care, and environmental monitoring are subject to mandatory calibration; this includes pressure gauges, air pressure gauges, and oxygen gauges. On August 6, 1991, the **Technical Supervision Bureau issued the \"Provisions on the Inspection of Working Measuring Instruments Subject to Mandatory Inspection (Trial)\\", which clearly defined the scope of instruments subject to mandatory inspection for pressure gauges (including pressure gauges, air pressure gauges, and oxygen gauges). 1. Pressure gauges used for safety protection must undergo mandatory calibration. It includes the following 7 categories: a、Measurement of the main boiler cylinder and feed water pressure areas; b、Measurement of the pressure in the air reservoirs and main pipes of fixed air compressors; c、Measurement of the oil pressure in generators and turbines, as well as the pressure in locomotives; d、Measurement of the pressure in medical autoclaves and pressure cookers; e、Measurement of pressure with alarm devices; f、Measurement of the pressure in sealed pressurized containers; g、Measurement of the pressure of harmful, toxic, and highly corrosive media. (for example: Bourdon tube pressure gauges, electric remote transmission pressure gauges, and electric contact pressure gauges). 2. Wind pressure gauges used for safety protection must undergo mandatory calibration. That is: the measurement of wind pressure and wind speed in the tunnels of a mine. (e.g.: mine air pressure gauges, mine wind speed meters). 3. Oxygen meters used for safety protection must undergo mandatory calibration. It includes the following 2 categories: a) measurement of the oxygen monitoring pressure during the filling of oxygen cylinders; b) measurement of the oxygen pressure that is explosive and poses a safety risk during the manufacturing process. 4. Oxygen meters used in medical and health fields must undergo mandatory calibration. That is, the measurement of oxygen pressure in float-type oxygen inhalers and oxygen supply devices used for oxygen delivery in hospitals. It can be seen that there are a total of 3 types and 11 categories of pressure gauges that require mandatory calibration; not all pressure gauges must undergo such calibration. Since medical oxygen gauges are not commonly seen during inspections related to safe production regulations, they will not be discussed; only the 3 types and 10 categories of pressure gauges used for safety protection will be addressed. II. Calibration cycle for pressure gauges subject to mandatory inspection Having defined the scope of pressure gauges that require mandatory inspection, this raises another key issue for discussion in this article: how to determine the calibration cycle for such pressure gauges. Paragraph 2, Article 10 of the Measurement Law of the People’s Republic of China stipulates that measurement verification must be carried out in accordance with measurement verification procedures. **The metrological verification regulations are formulated by the metrology administrative department of the State Council. In the absence of **metrological verification regulations, the relevant competent departments of the State Council and the metrological administrative departments of provinces, autonomous regions, and municipalities directly under the Central Government shall formulate respective departmental metrological verification regulations and local metrological verification regulations, which shall be filed with the metrological administrative department of the State Council.** Article 6 of the Measures for the Verification of Work Measurement Instruments Subject to Mandatory Verification in the People’s Republic of China stipulates that the periodicity for mandatory verification shall be determined by the measurement verification institution responsible for such verification in accordance with the relevant measurement verification regulations. It can be seen that laws, regulations, and departmental rules do not specify a clear calibration cycle for pressure gauges; it is necessary to refer to the relevant calibration procedures for such gauges. In enterprises, pressure gauges (including pressure gauges, air pressure gauges, and oxygen gauges) are mostly diaphragm-type general pressure gauges. The \"Specifications for the Calibration of Bourdon-Tube General Pressure Gauges, Pressure-Vacuum Meters, and Vacuum Meters\" (JJG 52-1999) were issued on December 22, 1999, and came into effect on April 1, 2000. They are applicable to the calibration of Bourdon-tube general pressure gauges with a measurement range of (0.1–100) MPa. Paragraph 5.5 of these regulations stipulates that the calibration interval for pressure gauges should generally not exceed six months. Regarding this, there are two points: first, the pressure gauges referred to in this clause should be those that are required by laws, regulations, and rules to undergo mandatory inspection, and not all pressure gauges. Secondly, \"the calibration cycle generally should not exceed six months.\" Reference should be made to the \"Notice on Strengthening and Adjusting the Management of Calibration Cycles for Measuring Instruments Subject to Mandatory Calibration\" (Quality and Technical Supervision Bureau Document No. [2000] 182); the calibration cycle specified in the regulations represents the maximum allowable cycle under normal conditions. The calibration cycle cannot be extended, but it can be shortened. If the calibration cycle is to be shortened, legal (including authorized) metrological calibration institutions must submit an application to the provincial quality and technical supervision bureau; only after approval and registration can such shortening be implemented. It should also be noted that the mandatory calibration of pressure gauges must be carried out by a statutory metrological calibration institution. In accordance with the \"Measures for the Supervision and Management of Legal Metrological Verification Institutions\" (**Order No. 15 of the Quality and Technical Supervision Bureau**), if a company obtains a \"Metrological Standard Assessment Certificate\" and is authorized by the quality and technical supervision authorities, then its own verification activities are also valid. III. Calibration of non-mandatory pressure gauges. As discussed above, there are 3 categories and 10 types of pressure gauges used for safety purposes, which must be calibrated at least once every six months. So, for devices that are not used for safety purposes – such as pressure gauges required for monitoring in ordinary process pipelines, containers, circulating water pipelines, heating pipelines, etc. – is it necessary to carry out calibration? And how should the calibration interval be determined? Article 9, Paragraph 2 of the Metrology Law of the People’s Republic of China stipulates that for metrological standard instruments and working metrological instruments that are not subject to mandatory calibration, the entities using them shall carry out regular calibration on their own or send them to other metrology calibration institutions for calibration; meanwhile, the metrology administrative departments at the county level and above shall conduct supervision and inspections. The Detailed Rules for the Implementation of the Metrology Law of the People’s Republic of China were approved by the State Council on January 19, 1987, and issued by the **Metrology Bureau on February 1, 1987. Article 12 of the Detailed Rules for the Implementation of the Metrology Law of the People’s Republic of China stipulates that enterprises and institutions shall be equipped with metrological testing facilities suitable for production, scientific research, and business management; they shall establish specific procedures and regulations for calibration, specify a detailed list of the metrological instruments under their control along with the corresponding calibration intervals, and ensure that the metrological instruments that are not subject to mandatory calibration are calibrated on a regular basis. It can be seen that pressure gauges that are not subject to mandatory calibration still need to be calibrated regularly, although the calibration interval is determined by the enterprise itself. IV. Calibration of Pressure Gauges Used in Special Equipment. The previous sections discussed the calibration range and frequency for pressure gauges. Some readers may ask how to determine the calibration frequency for those pressure gauges used in pressure vessels, pressure pipelines, and boilers (as safety accessories) in the context of law enforcement and supervision. 1. Calibration of Pressure Gauges Used in Simple Pressure Vessels. On January 22, 2007, the **General Administration for Quality Supervision, Inspection and Quarantine issued the “Regulations on Safety Technical Supervision of Simple Pressure Vessels” (TSG R0003-2007), which came into effect on July 1, 2007. At the same time, in accordance with the \"Frequently Asked Questions\" issued by the Special Equipment Safety Supervision Bureau of the General Administration of Quality Supervision, Inspection and Quarantine on October 9, 2007, it depends on the date on which the simple pressure vessel was put into use to determine whether a pressure gauge used for such vessels needs to be calibrated. For simple pressure vessels put into use after July 1, 2007, the pressure gauges do not require calibration. If a simple pressure vessel is continued to be used beyond its recommended service life, the pressure gauge must undergo regular mandatory calibration. For simple pressure vessels put into use before July 1, 2007, the pressure gauge, as a safety accessory, must be regularly calibrated. 2. Calibration of pressure gauges for fixed-pressure vessels On August 31, 2009, the **General Administration for Quality Supervision, Inspection and Quarantine issued the \"Regulations on Safety Technical Inspection of Fixed-Pressure Vessels\" (TSG R0004-2009), which came into effect on December 1, 2009. Article 147 of these regulations stipulates that the calibration and maintenance of pressure gauges shall comply with the relevant provisions of the **metrology authorities: Pressure gauges must be calibrated before installation, and a red line indicating the maximum operating pressure shall be marked on the dial, along with the date for the next calibration. After calibration, the pressure gauge should be sealed with a lead seal. 3. Calibration of pressure gauges for industrial pipelines: On May 8, 2009, the **General Administration for Quality Supervision, Inspection and Quarantine issued the \"Regulations on Safety Technical Supervision of Pressure Pipelines – Industrial Pipelines\" (TSG D0001, 2009), which came into effect on August 1, 2009. This regulation does not provide specific provisions for the calibration of pressure gauges; it only sets out general requirements in Article 151, stating that the accuracy class, range, and installation location of pressure gauges used in pipelines must meet the requirements of relevant safety technical specifications and corresponding standards. The \"Regulations for Periodic Inspection of In-service Industrial Pipelines\" classifies pressure gauges as safety protection devices, but it does not specify any requirements regarding the inspection of pressure gauges used in industrial pipelines; it only requires that such gauges be replaced immediately once their calibration validity period has expired. 4. Calibration of pressure gauges for boilers. At present, the safety supervision of boilers is carried out separately according to their type. The main regulations and standards in this regard include the \"Safety Technical Supervision Regulations for Steam Boilers\" (Labor Ministry Order No. 276), the \"Safety Technical Supervision Regulations for Hot Water Boilers\" (Labor Boiler Affairs Document No. 74), the \"Safety Technical Supervision Regulations for Organic Heat Carrier Boilers\" (Labor Ministry Order No. 356), and the \"Regulations on Safety Supervision of Small and Atmospheric Pressure Hot Water Boilers\" (Quality Supervision Bureau Order No. 11). Article 151 of the «Regulations on Safety Inspection of Steam Boilers» stipulates that the pressure gauges selected must meet the requirements of relevant technical standards, and their calibration and maintenance must comply with the regulations set by the **metrology authorities. Article 109 of the “Regulations on Safety Technical Inspection of Hot Water Boilers” stipulates that the installation, calibration, and maintenance of pressure gauges shall comply with the regulations set by the **metrology authorities. A pressure gauge should be calibrated before use, and it is not the red line on the dial that indicates the operating pressure. After installation, pressure gauges must be calibrated at least once a year. Article 17, Paragraph 2 of the “Regulations on Safety Technical Supervision of Organic Heat Carrier Boilers” (Document No. 356 issued by the Ministry of Labor) stipulates that pressure gauges shall be calibrated at least once a year, and after calibration, they must be sealed with lead. Article 24 of the **Regulations on the Safety Supervision of Small and Atmospheric Pressure Hot Water Boilers** (Order No. 11 of the Quality and Technical Supervision Bureau) stipulates that the pressure gauges of small boilers shall be calibrated in accordance with relevant regulations. Based on the above analysis, it can be seen that the verification of pressure gauges used for special equipment can be divided into two main categories: first, whether mandatory verification is required for simple pressure vessels depends on the date when such vessels are put into service. Secondly, the calibration of pressure gauges used in fixed-pressure vessels, industrial pipelines, and boilers must comply with the regulations set by the metrology authorities; pressure gauges for hot water boilers and organic heat carrier boilers can be calibrated once a year. V. Calibration of pressure gauges in chemical enterprises The calibration methods for pressure gauges discussed above are applicable to general enterprises. However, chemical enterprises face higher risks; what are then their requirements regarding the calibration of pressure gauges? On October 10, 1988, the Ministry of Chemical Industry and the **Technical Supervision Bureau jointly issued the \"Provisional Measures for the Classification and Management of Measuring Instruments in the Chemical Industry,\" which classifies such instruments into three grades: A, B, and C. In accordance with the “Catalogue for Hierarchical Management of Measuring Instruments in Chemical Production Enterprises” appended to this method, the classification and verification intervals for pressure gauges used in chemical enterprises are as follows: Grade A: Pressure gauges used for safety protection must be verified at least once every six months. Class B: Pressure gauges used for process control, with a calibration interval corresponding to the maintenance period of the equipment. Class C: 1. Pressure gauges used for monitoring, with a calibration interval of 1–2 years; pressure gauges used for safety protection: 1. Measurement of pressure in boilers and water supply systems; 2. Measurement of pressure with an alarm device; 3. Measurement of pressure in media that are harmful, toxic, or highly corrosive. A: Pressure gauges for fixed pressure vessels used in process control must be calibrated at least once every six months.
B: The calibration interval for pressure gauges used for monitoring corresponds to the maintenance cycle of the equipment.
C: The calibration interval for pressure gauges used in simple pressure vessels is 1–2 years; this interval is determined based on specific time points and the service life of the gauges.
*** Pressure gauges installed prior to July 1, 2007, must also be calibrated regularly. Those put into use later do not require calibration. If it continues to be used beyond its recommended service life, regular mandatory verification is required. 2. The pressure gauge for monitoring does not require periodic calibration; it is replaced as soon as a failure occurs. In fact, many companies currently implement a hierarchical management system for pressure gauges as well. The risk level of ordinary enterprises is lower than that of chemical enterprises; therefore, law enforcement officers can fully use the aforementioned methods to determine whether the calibration of pressure gauges in ordinary enterprises complies with regulations. VI. Discussion on Administrative Penalties for Failure to Regularly Calibrate Pressure Gauges The Metrology Law of the People’s Republic of China stipulates that the competent authority for supervising measuring instruments is the metrology administrative department. However, with the adjustment of administrative functions, it is now under the responsibility of the quality and technical supervision department. When safety inspection officers conduct inspections of enterprises, they may also encounter the issue of pressure gauges that have not been calibrated on a regular basis. So how should this be handled? First, let’s take a look at the penalties stipulated by the quality supervision authorities for such cases. 1. Administrative penalties imposed by quality supervision authorities for pressure gauges that have not been regularly calibrated. On August 25, 1990, the **Technical Supervision Bureau issued the ‘Rules on Penalties for Metering Violations’** (Order No. 14 of the Technical Supervision Bureau), which apply to administrative penalties for violations of metering laws and regulations. Article 12, Paragraph (1) of the Detailed Rules for Punishing Violations in Metrology stipulates that for work measuring instruments subject to mandatory calibration, if they are not calibrated as required or continue to be used beyond their calibration deadline, the user shall be ordered to stop using them, and may also be fined up to 500 yuan. Article 12, Paragraph (2) of the Detailed Rules for Punishing Metering Violations stipulates that for metering instruments that are not subject to mandatory inspection, if they are not regularly inspected by the owners themselves as required, or are not sent to other metering inspection agencies authorized to conduct such inspections, they shall be ordered to stop being used, and a fine of up to 200 yuan may be imposed; if they continue to be used despite failing the inspection, they shall again be ordered to stop being used, and a fine of up to 500 yuan may be imposed. It can be seen that both pressure gauges subject to mandatory inspection and those not subject to such inspection, when not undergoing regular calibration, constitute illegal acts, and the quality supervision authorities shall impose corresponding administrative penalties. 2. Administrative penalties imposed by safety supervision departments for pressure gauges that have not been regularly calibrated According to the existing laws and regulations on metrology, safety supervision departments do not have the authority to impose administrative penalties for the violation of not having pressure gauges calibrated on a regular basis. In accordance with Article 60 of the Work Safety Law, if it is discovered that a \"pressure gauge has not been regularly calibrated,\" the matter shall be promptly referred to the quality and technical supervision department. However, it is impractical in actual work to find that pressure gauges are handed over without regular inspection. Furthermore, the transfer requires a certain period of time; during this period, if a production safety accident occurs due to problems with the pressure gauge, the law enforcement officers shall bear corresponding responsibility. The author believes that pressure gauges used for safety protection should be considered safety equipment, and in accordance with Article 29 of the Work Safety Law, production and business operations entities must conduct regular inspections of such safety equipment. Furthermore, in accordance with Article 83, Item (6) of the Work Safety Law, a \"Order to Rectify within a Time Limit\" can be issued to require the enterprise to make corrections within a specified period. Most companies will make the necessary corrections after receiving the \"Order to Rectify within a Set Time Limit\". When a reinspection is conducted upon the expiration of the \"Order to Make Rectifications within a Set Time Limit,\" if the enterprise fails to make the necessary corrections, in order to avoid unnecessary administrative reviews and lawsuits, the safety supervision department should not impose administrative penalties, but rather transfer the case to the quality supervision department. For pressure gauges that are not subject to mandatory calibration (such as those of Class B and Class C), if a company fails to carry out regular calibrations in accordance with the relevant management regulations and rules, safety inspection officers can decide, based on the actual situation (such as the number of pressure gauges or the length of time they have not been calibrated), whether to hand the matter over to relevant authorities or require the company to make corrections within a specified time frame. VII. Conclusions 1. A total of 10 types of pressure gauges in 3 categories used for safety protection are subject to mandatory calibration, with a calibration interval of at least once every six months; 2. Pressure gauges that are not subject to mandatory calibration still need to be calibrated regularly, with the interval determined by the enterprises themselves; 3. Whether pressure gauges used in simple pressure vessels require mandatory calibration depends on the date on which those vessels come into use; 4. The calibration of pressure gauges used in fixed pressure vessels, industrial pipelines, and boilers must comply with the regulations set by the metrology authorities; 5. Pressure gauges used in chemical enterprises are classified into grades A, B, and C, with different calibration intervals for each grade, and pressure gauges used for monitoring do not require periodic calibration; 6. If safety inspection officers discover that pressure gauges have not been calibrated regularly, they can refer the matter to the quality supervision department or require the enterprise to make corrections within a specified time frame, and the safety inspection department should not impose administrative penalties. Note: This article is from the Internet. Pressure gauges used for safety protection: 1. Measurement of pressure in boilers and water supply systems; 2. Measurement of pressure with alarm functions; 3. Measurement of pressure in harmful, toxic, or highly corrosive media. A: Pressure gauges for fixed pressure vessels used in process control must be calibrated at least once every six months.
B: The calibration interval for pressure gauges used for monitoring corresponds to the maintenance cycle of the equipment.
C: The calibration interval for pressure gauges used in simple pressure vessels is 1–2 years; this interval is determined based on specific time points and the service life of the gauges.
*** Pressure gauges installed prior to July 1, 2007, must also be calibrated regularly. Those put into use later do not require calibration. If it continues to be used beyond its recommended service life, regular mandatory verification is required.