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►How to set up alarms and interlocks for tank level and emergency shut-off valves in DCS and instrument safety systems? * * What do specifications and documents require for this? ►Industry expert Fan Yongfeng, a senior engineer, gave an in-depth explanation of the relevant knowledge about the liquid level in the tank area and the alarm and interlocking of emergency shut-off valves. ►Some of the questions that instrument workers often encounter in terms of tank level and alarm and interlocking of emergency shut-off valves will naturally have answers! I hope you read the article with questions: ①The same storage tank is equipped with at least several different types of liquid level detection instruments? ②Do key storage tanks such as liquefied gas and highly toxic liquids that constitute major hazard sources must be equipped with emergency cut-off devices? ③Do all storage tanks have to be equipped with high and low liquid level alarms and interlocks? ④If an emergency shut-off valve is installed, are there any requirements for the installation location? ⑤Is it necessary to install an emergency shut-off valve interlock button on site? Are there any installation location requirements? GB50074-2014 "Petroleum Depot Design Code" ◆ Setup requirements 15.1 Automatic control system and instrumentation 15.1.1 Storage tanks with a capacity greater than 100m3 should be equipped with liquid level measurement remote transmission instruments, and should comply with the following regulations: 1. The continuous measurement signal of liquid level should be connected to the automatic control system using analog signals or communication methods. ； 2 High and low liquid level alarms should be set up in the automatic control system ； 3 The setting height of the storage tank high liquid level alarm should comply with the relevant provisions of the current industry standard "Petrochemical Storage and Transportation System Tank Farm Design Specification" SH/T 3007 ； 4. The setting height of the low liquid level alarm of the storage tank should meet the requirements of preventing cavitation of the pump. The setting height of the low liquid level alarm of the outer floating roof storage tank and the inner floating roof storage tank (from the bottom of the tank) should be 0.2m or more higher than the height of the floating roof falling to the bottom. 15.1.4 The liquid level measuring instrument used for the high and low liquid level alarm signals of the storage tank should be a separate continuous liquid level measuring instrument or liquid level switch, and alarms and interlocks should be set in the automatic control system. ◆Interlocking requirements 15.1.2 The following storage tanks should be equipped with high and high liquid level alarms and interlocks. The high and high liquid level alarms should be able to interlock and close the tank inlet pipeline control valve at the same time.: Category A, B and B liquid storage tanks with turnover times greater than 6 times per year and a capacity greater than or equal to 10,000m3 ； Category A and B liquid storage tanks with turnover times less than or equal to 6 times in 2 years and a capacity greater than 20,000m3 ； 3 Storage tanks for storing Class I and II toxic liquids. 15.1.3 External floating roof storage tanks and internal floating roof storage tanks with a capacity greater than or equal to 50,000m3 should be equipped with low liquid level alarms. The low and low liquid level alarm setting height (from the bottom of the tank) should not be lower than the height of the floating roof. Low and low liquid level alarms can interlock and stop the pump at the same time. 15.1.4 The liquid level measuring instrument used for the high and low liquid level alarm signals of the storage tank should be a separate continuous liquid level measuring instrument or liquid level switch, and alarms and interlocks should be set in the automatic control system. [Explanation] 15.1.4 "A separate continuous liquid level measuring instrument or liquid level switch" means that in addition to "a remote transmission instrument for liquid level measurement", a set of liquid level measuring instruments specifically used for high and low liquid level alarms and interlocking of the storage tank must also be set up. ◆Setting and interlocking requirements 15.1.2 The following storage tanks should be equipped with high and high liquid level alarms and interlocks. The high and high liquid level alarms should be able to interlock and close the tank inlet pipeline control valve at the same time. ； 15.1.7 In addition to being able to be operated on-site, the important process pumps, fire pumps, storage tank agitators and other electric equipment and control valves of the primary oil depot should also be able to be controlled and displayed in the control room. In addition to being able to operate on-site, the important process pumps, fire pumps, storage tank mixers and other electric equipment and control valves in the secondary petroleum depot should also be able to be controlled and displayed in the control room. 15.1.11 The start and stop of the fire pump in the first-level oil depot and the switches of the control valves on the fire water pipeline and foam liquid pipeline should be remotely controlled in the fire control room. The main console should display the pump operating status and the valve position signal of the control valve. [Explanation of Articles] 15.1.7 This stipulates that the status of electric equipment can be monitored in real time and abnormal situations can be handled in a timely manner. ； 15.1.11 This provision is to ensure that the fire protection system can be activated quickly and fires can be put out in a timely manner. GB 50737-2011 "Code for Design of Petroleum Reserves" ◆Setup requirements 11.1 Automatic control system and instruments 11.1.2 Each oil tank should be equipped with continuous liquid level measurement instruments, high and high liquid level switches, and low and low liquid level switches, and should comply with the following regulations: 1 The accuracy of the liquid level gauge should be better than ±1mm ； 2 The continuous liquid level meter should have the functions of high liquid level alarm, low liquid level alarm and high and high liquid level interlocking to close the oil tank inlet valve. The low liquid level alarm setting height (from the tank bottom plate) should not be less than 2m ； 3. The high-high liquid level switch should have the function of high-high liquid level interlocking to close the oil tank inlet valve. ； 4 The low and low liquid level switch should have the function of low and low liquid level interlocking to stop the oil pump and close the pump outlet valve. The setting height of the low and low liquid level switch (from the bottom of the tank) can be no less than 1.85m. ； [Explanation of Article] 11.1.2 Liquid level is the most important parameter that needs to be monitored in oil tanks, so it is required that "each oil tank should be equipped with a continuous liquid level measuring instrument." High liquid level interlocking and closing the inlet valve can prevent oil spillage when the oil tank is filled, which is a necessary safety protection measure. The low-low level switch is set to prevent the floating roof legs from falling to the bottom of the tank. The floating roof of a floating roof tank generally floats on the oil surface and is in direct contact with the oil surface. It can effectively suppress the volatilization of oil vapor and there is no gas phase space except for the sealing ring, which greatly eliminates the explosive environment. What needs to be noted during use is that except for maintenance of oil tanks, the floating roof must be prevented from falling to the bottom. Once the floating roof falls to the bottom, a gas phase space will appear between the oil surface and the floating roof. For crude oil, if there is a gas phase space, there will be explosive gas. * * Increased fire hazard. In a fire accident at a large oil depot in the north in 2010, multiple 10×104m3 oil tanks were roasted by flames at a close distance of more than 10 meters, but only the No. 103 tank was ignited and eventually burned. The main reason was that the floating roof of the tank had fallen to the ground at that time, and there was a small amount of oil stored in the tank. Under the baking of the flame, the oil and gas existing in the gas phase space could easily be detonated and ignited. The general height of the floating roof legs is 1.8m, so it is stipulated that "the setting height of the low and low liquid level switch (from the tank bottom plate) cannot be less than 1.85m” ； Considering that there is a processing time of 10 to 15 minutes after the alarm, it is stipulated that "the low liquid level alarm setting height (from the bottom of the tank) should not be less than 2m." ◆Setting requirements 11.1.10 The start and stop of fire pumps and the switches of control valves on fire water pipes and foam liquid pipes should be controlled by programmed start and stop in the fire control room. The main console can display the pump operating status and the valve position signal of the electric valve. GB 50160-2018 "Code for Design of Fire Protection for Petrochemical Enterprises" Setting Requirements 6.2.23 Storage tanks for flammable liquids should be equipped with liquid level gauges and high liquid level alarms. If necessary, automatic interlocking and feeding facilities can be installed. ； An automatic dehydrator should also be installed. Interlocking requirements: 6.3 Above-ground storage tanks for liquefied hydrocarbons, combustible gases, and combustion-supporting gases ； 6.3.11 Liquefied hydrocarbon storage tanks should be equipped with liquid level gauges, thermometers, pressure gauges, safety valves, as well as high liquid level alarms and high and high liquid level automatic interlocking measures to cut off the feed. [Explanation of Articles] 6.3.11 NFPA 58 "Liquefied Petroleum Gas Specification" stipulates: “High liquid level alarms should be installed on refrigerated liquefied petroleum gas containers." “Refrigerated Liquefied Petroleum Gas containers shall be equipped with a high level flow cut-off device which shall be independent of all instrumentation. ”Even if the storage tank is at room temperature, this regulation is safer. The high-liquid-level automatic interlocking cutting-off feeding device is the last effective means to prevent oil tanks from erupting. It is currently commonly used and is a reasonable setting. ◆Setting and interlocking requirements 6.3.14 Full-pressure liquefied hydrocarbon storage tanks should adopt a secondary dehydration system with anti-freezing measures, and an emergency shut-off valve should be installed at the root of the tank. 6.4 Loading and unloading facilities for flammable liquids and liquefied hydrocarbons 6.4.1 An emergency shut-off valve that is easy to operate should be installed on the input pipeline for flammable liquids (except lubricating oil) 10m away from the edge of the loading platform. ； 6.4.2 When there is no buffer tank in the station, an easy-to-operate emergency shut-off valve should be installed on the loading and unloading pipeline 10m away from the crane position of the loading and unloading truck. ； 7 Pipe layout 7.2 Process and public material pipelines 7.2.15 The inlet pipeline from liquefied hydrocarbons and flammable liquid equipment with operating temperatures equal to or higher than the auto-ignition point to the pump should be equipped with a cut-off valve near the root of the equipment. When the equipment volume exceeds 40m3 and the distance from the pump is less than 15m, the cut-off valve should be a remote control valve with a manual function. The distance between the local operation button of the remote control valve and the pump should not be less than 15m. 7.4.7 When the length of the inter-plant pipeline is greater than 5km, emergency shut-off valves, flow and pressure monitoring facilities should be installed on the pipelines within the walls of the upstream and downstream enterprises or the land boundary lines. 8.4.5 Above-ground vertical storage tanks for flammable liquids should be equipped with fixed or mobile fire cooling water systems, and their water supply range, water supply intensity and installation method should comply with the following regulations: 5 The control valve should be located outside the fire dike and should not be less than 15m away from the protected tank wall. The fire cooling water pipes installed behind the control valve and on the storage tank should be galvanized steel pipes. 8.10.10 The installation of fixed fire cooling water pipes for full-pressure and semi-refrigerated liquefied hydrocarbon storage tanks shall comply with the following regulations: 2 The fire cooling water system can use manual or remote control valves. When the storage tank volume is equal to or greater than 1000m3, the remote control valve should be used ； 3. The control valve should be located outside the fire dike and should not be less than 15m away from the protected tank wall. ； [Explanation of Articles] 6.3.14 An emergency shut-off valve is installed at the root of the storage tank to reduce losses in the event of an accident in the pipeline system. 7.2.15 The purpose of this provision is to cut off the material in time when a fire occurs in the downstream equipment directly connected to the tank. For example, if a pump downstream of a liquefied hydrocarbon tank in a product refining device of a factory accidentally catches fire, personnel cannot get close to the pump and close the shut-off valve, and there is no shut-off valve on the pipeline between the pump and the tank near the root of the tank. The fire is extinguished only after the liquefied hydrocarbons in the tank are burned out, causing heavy losses. API Std 2510 "Design and Construction of Liquefied Petroleum Gas (LPG) Facilities" Regulations: The shut-off valve on the liquefied hydrocarbon pipeline should be arranged as close as possible to the tank, preferably on the mouth of the tank wall. To facilitate operation and maintenance, the installation location of the shut-off valve should be easily accessible and quickly accessible. When the volume of a liquefied hydrocarbon tank exceeds 10,000 gal (≈38m3), within 15 minutes of a fire, all shut-off valves on the pipelines located under the highest liquid level of the tank should be able to be automatically closed or operated remotely. The shut-off valve control system should be fire-resistant and the shut-off valve should be manually operable. Referring to API standards, the volume of liquefied hydrocarbon equipment is adjusted to 40m3. Considering that flammable liquid pumps with operating temperatures equal to or higher than the auto-ignition point have a higher probability of accidents, it is required that the inlet pipes from flammable liquid equipment with operating temperatures equal to or higher than the auto-ignition point to the pump should be equipped with a shut-off valve near the root of the equipment. GB 17681-1999 "Technical Requirements for Acceptance of Safety Monitoring and Early Warning Systems in Flammable and Explosive Tank Farms" ◆Setup requirements 5.5 Liquid storage tanks must be equipped with liquid level detection instruments. The same storage tank must be equipped with at least two different types of liquid level detection instruments. Tanks storing flammable and explosive media should be equipped with high and low liquid level alarm circuits, and if necessary, should also be equipped with an interlocking system between the liquid level and relevant process parameters. AQ 3036-2010 "Specifications for the installation of on-site safety monitoring equipment in tank farms with major hazard sources for hazardous chemicals" ◆Setup requirements 6.3.1 The storage tank should be equipped with a liquid level monitor and should have high and low liquid level alarm functions. ◆Interlocking requirements 6.3.7 Large (5000 m3 and above) flammable liquid storage tanks and hazardous chemical pressure storage tanks above 400 m3 should be equipped with high and high liquid level monitoring alarm and interlocking control systems. ◆Setting requirements 5 Setting requirements for interlocking control equipment 5.1 Interlocking automatic control equipment for parameters such as temperature, liquid level, pressure and ambient temperature of the storage tank can be set according to the actual situation, including automatic cutting or transfer of materials and spray cooling equipment. SH/T 3007-2014 "Specifications for Design of Tank Areas for Petrochemical Storage and Transportation Systems" ◆Setup requirements 5 Normal and low pressure storage tank areas 5.4 Instrument selection and installation 5.4.1 Storage tanks with a capacity greater than 100m3 should be equipped with remote transmission instruments for continuous liquid level measurement. 5.4.2 High and low liquid level alarms should be set up in the automatic control system and should meet the following requirements: a) The setting height of the storage tank high liquid level alarm should not be higher than the designed storage high liquid level of the storage tank. ； b) The set height of the tank's low liquid level alarm should not be lower than the designed storage low liquid level of the tank. 5.4.5 The high and low liquid level alarm signals and liquid level measuring instruments of the storage tank should use separate continuous liquid level measuring instruments or liquid level switches, and the alarm signals should be transmitted to the automatic control system. 6 Pressure storage tank area 6.3 Selection and installation of storage tank instruments 6.3.2 A set of remote transmission instruments and a set of local indicating instruments should be installed for pressure storage tank liquid level measurement. The local indicating instruments should not use glass plate level gauges. 6.3.3 The remote transmission instrument for liquid level measurement should be equipped with high and low liquid level alarms. The setting height of the high liquid level alarm should be the designed storage high liquid level of the storage tank. ； The setting height of the low liquid level alarm should meet the requirement that the pump will not cavitate within 10 to 15 minutes from the start of the alarm. ◆Interlocking requirements 5.4.3 Storage tanks storing Class I and II toxic liquids, Class A B and Class B A flammable liquid storage tanks with a capacity greater than or equal to 3000m3, and other liquid storage tanks with a capacity greater than or equal to 10000m3 should be equipped with high and high liquid level alarms and interlocks. The high and high liquid level alarms should be interlocked to close the tank inlet pipeline control valve. 5.4.4 The raw material storage tank of the device should be equipped with a low liquid level alarm, and the low and low liquid level alarms should be interlocked to stop the pump. 5.4.5 The high and low liquid level alarm signals and liquid level measuring instruments of the storage tank should use separate continuous liquid level measuring instruments or liquid level switches, and the alarm signals should be transmitted to the automatic control system. 6 Pressure storage tank area 6.3 Selection and installation of storage tank instruments 6.3.4 The pressure storage tank should be equipped with a set of liquid level measuring instruments or liquid level switches dedicated to high liquid level alarm and interlocking to cut off the tank feed pipe valve. The setting height of the high liquid level alarm should not be greater than the height when the liquid volume reaches 90% of the calculated volume of the storage tank. [Explanation of Articles] 5.4.1 Liquid level is the most important parameter that needs to be monitored in storage tanks, so this article requires that "storage tanks should be equipped with remote transmission instruments for liquid level measurement." 5.4.2 The purpose of setting high (low) liquid level alarm is to predict that the liquid level in the tank will rise (lower) to the specified limit height. The operator is required to complete the switching of the tank within the specified time after hearing the alarm to avoid accidents. 5.4.3 High and high liquid level interlocking and closing the inlet valve can prevent the storage tank from overflowing when feeding. Stricter safety protection measures need to be taken for the three situations listed in this article. SH 3136-2003 "Safety Design Code for Liquefied Hydrocarbon Spherical Storage Tanks" ◆Setup requirements 5.3.1 Liquefied hydrocarbon spherical storage tanks should be equipped with local and remote level gauges, but glass plate level gauges should not be used. The liquid level gauge used should be safe and reliable, and the number of openings on the liquefied hydrocarbon spherical storage tank should be reduced as much as possible. 5.3.2 Liquefied hydrocarbon spherical storage tanks should be equipped with high liquid level alarms and high and high liquid level interlocks. If necessary, a low liquid level alarm should be installed. ◆Interlocking requirements 5.3.2 Liquefied hydrocarbon spherical storage tanks should be equipped with high liquid level alarms and high and high liquid level interlocks. If necessary, a low liquid level alarm should be installed. 5.3.3 For liquefied petroleum balloon storage tanks loaded and unloaded by tank trucks under intermittent operation, a high-liquid level automatic interlocking emergency cut-off feeding device should be installed. For single-component liquefied hydrocarbons or spherical storage tanks that operate continuously in refining and chemical production units, the interlocking requirements should be determined according to the requirements of its upstream and downstream process production processes. ◆Setting and interlocking requirements 6.1 Emergency shut-off valve The liquid phase inlet and outlet of the liquefied petroleum balloon storage tank should be equipped with an emergency shut-off valve, and its location should be close to the spherical storage tank. AQ3053-2015 "Safety Technical Specifications for Vertical Cylindrical Steel Welded Storage Tanks" ◆Setup requirements 12.2.2 Liquid level limit accessory flammable liquid storage tanks should be equipped with liquid level gauges, high and low liquid level alarm devices, and high and high liquid level alarm devices in accordance with the requirements and operation needs of the specification, and the alarm and liquid level display information should be transmitted to the control room. Storage tanks that are frequently operated should be equipped with automatic interlocking emergency shut-off devices. Large tanks should be equipped with high and low liquid level alarm devices, high and high liquid level alarm devices and emergency cut-off devices, and measures should be taken to interlock high and high liquid level alarms with emergency cut-off devices. Emergency cut-off valve interlock buttons should be installed outside the fire embankment and at the control room operating station. When a high liquid level alarm or fire occurs in the storage tank, the feed cut-off valve can be closed remotely or manually on site. After the cut-off valve is closed, the feed pump should be automatically interlocked to stop. ◆Interlocking requirements 12.2.2 Large tanks with liquid level limit accessories should be equipped with high and low liquid level alarm devices, high and high liquid level alarm devices and emergency cut-off devices, and measures should be taken to interlock high and high liquid level alarms with emergency cut-off devices. Emergency cut-off valve interlock buttons should be installed outside the fire embankment and at the control room operating station. When a high liquid level alarm or fire occurs in the storage tank, the feed cut-off valve can be closed remotely or manually on site. After the cut-off valve is closed, the feed pump should be automatically interlocked to stop. ◆Setting requirements 6.13 Cut-off valve A main cut-off valve should be installed near the tank material inlet and outlet pipes. For large storage tanks, valves with pneumatic, hydraulic or electric actuators should be used. When the actuator is electric, its power cable, signal cable and electric actuator should be protected against fire. The shut-off valve should have automatic closing and manual closing functions. Manual closing includes remote manual closing and on-site manual closing. "Notice on Further Strengthening the Safety Management of Chemical Tank Areas" issued by the Work Safety Supervisor on the 3rd No. 68 ◆Setting requirements (1) Further improve the monitoring and control facilities of chemical tank areas. Set up high and low liquid level alarms for storage tanks in accordance with regulatory requirements, and use ultra-high liquid level automatic interlocking to close the tank feed valve and ultra-low liquid level automatic interlocking to stop material transportation. Ensure that the flammable, explosive, toxic and harmful gas leakage alarm system is intact and available. Emergency shut-off valves should be installed in key storage tanks such as large, liquefied gas and highly toxic chemicals. ◆Setup and interlocking requirements (1) Further improve the monitoring and control facilities in chemical tank areas. Set up high and low liquid level alarms for storage tanks in accordance with regulatory requirements, and use ultra-high liquid level automatic interlocking to close the tank feed valve and ultra-low liquid level automatic interlocking to stop material transportation. Ensure that the flammable, explosive, toxic and harmful gas leakage alarm system is intact and available. Emergency shut-off valves should be installed in key storage tanks such as large, liquefied gas and highly toxic chemicals. "Notice on Further Strengthening the Safety Design Management of Hazardous Chemical Construction Projects" issued by Jianzongguan No. 3.76 ◆Setting requirements (14) The design unit shall determine the standard specifications adopted for this project based on the characteristics of the hazard sources of the construction project and the scope of application of the standard specifications. For construction projects involving "two key points and one major", they should at least meet the requirements of the following current standards and specifications, and the most stringent safety provisions shall prevail. (19) New chemical equipment must be designed and equipped with an automated control system. The need to equip a safety instrumented system should be determined based on the process hazard and risk analysis results. Large and medium-sized new projects involving key supervision of hazardous chemical processes must carry out safety instrument system design in accordance with relevant standards such as "Functional Safety of Safety Instrument Systems in the Process Industry Field" (GB/T21109) and "Design Specifications for Safety Instrument Systems in Petrochemical Industry" (GB50770). (22) The inlet and outlet material pipelines of toxic material storage tanks, cryogenic storage tanks and pressure spherical tanks should be equipped with automatic or manual remote-controlled emergency shut-off facilities. ◆Interlocking requirements (19) New chemical equipment must be designed with an equipment automation control system. The need to equip a safety instrumented system should be determined based on the process hazard and risk analysis results. Large and medium-sized new projects involving key supervision of hazardous chemical processes must carry out safety instrument system design in accordance with relevant standards such as "Functional Safety of Safety Instrument Systems in the Process Industry Field" (GB/T21109) and "Design Specifications for Safety Instrument Systems in Petrochemical Industry" (GB50770). (22) The inlet and outlet material pipelines of toxic material storage tanks, cryogenic storage tanks and pressure spherical tanks should be equipped with automatic or manual remote-controlled emergency shut-off facilities. Order No. 40 of the State Administration of Work Safety, "Interim Provisions on the Supervision and Management of Major Hazardous Sources of Hazardous Chemicals" ◆ Establishment Requirements Article 13 Hazardous chemicals units shall establish and improve a safety monitoring and control system and improve control measures in accordance with the following requirements based on the types, quantities, production and use processes (methods) of hazardous chemicals that constitute major hazard sources, or the actual conditions of relevant equipment and facilities, etc.: (1) Major hazardous sources are equipped with continuous collection and monitoring systems for temperature, pressure, liquid level, flow, composition and other information, as well as flammable gas and toxic and harmful gas leakage detection and alarm devices, and have functions such as information remote transmission, continuous recording, accident warning, and information storage. ； Level one or level two major hazard sources, equipped with emergency stop function. Recorded electronic data will be kept for no less than 30 days ； (2) Chemical production equipment with major hazard sources is equipped with automated control systems that meet safety production requirements. ； Level 1 or level 2 major hazard sources, equipped with emergency stop system ； (3) Set up emergency cut-off devices for key facilities such as toxic gases, highly toxic liquids and flammable gases in major hazard sources ； For facilities with toxic gases, emergency disposal devices for leaks must be installed. Level 1 or level 2 major hazard sources involving toxic gases, liquefied gases, and highly toxic liquids are equipped with independent safety instrumented systems (SIS) ； ◆Interlocking Requirements Article 13 Hazardous chemicals units shall establish and improve a safety monitoring and control system and improve control measures in accordance with the following requirements based on the types, quantities, production and use processes (methods) of hazardous chemicals that constitute major hazard sources or the actual conditions of relevant equipment and facilities.: (3) Set up emergency cut-off devices for key facilities such as toxic gases, highly toxic liquids and flammable gases in major hazard sources ； For facilities with toxic gases, emergency disposal devices for leaks must be installed. Level 1 or level 2 major hazard sources involving toxic gases, liquefied gases, and highly toxic liquids are equipped with independent safety instrumented systems (SIS) ； Safety Supervision Manager No. 3 No. 62 * * Notice of the State Administration of Work Safety on Issuing Opinions on Containing Major Accidents of Hazardous Chemicals and Fireworks and Firecrackers ◆ Establishment Requirements (4) Starting from January 1, 2017, all hazardous chemical tank areas that constitute primary and secondary major hazard sources and do not have an emergency stop (emergency cut-off) function will be stopped from use. ； Su Anjian No. 109 "Opinions on Standardizing the Transformation of Automatic Control Technology in Chemical Enterprises" ◆ Setup requirements 1. Newly built production devices or storage facilities within the scope of transformation must be equipped with automatic control systems, select safe and reliable automatic control instruments, interlocking protection systems, and be equipped with necessary toxic, harmful, flammable and explosive gas leakage detection and alarm systems and fire alarm systems. Production equipment with an investment scale of more than 100 million yuan (including 100 million yuan) and with high risks (cracking, hydrogenation, polymerization, fluorination, nitration, peroxidation processes, etc., the same below) must be equipped with an emergency shutdown system on the basis of automatic control. 2. Existing production equipment involving dangerous processes must complete automatic control technology transformation within the specified time limit to realize automatic control of the process and automatic alarms of major parameters such as temperature and pressure. Those with high risks or conditions must be equipped with distributed control systems and emergency stopping systems to achieve remote operation. Hazardous chemical production enterprises must complete transformation before renewing (issuing) a production safety license. 3. Existing storage facilities within the scope of transformation must complete automatic control technology transformation within the specified time limit. Storage areas for highly toxic, flammable and explosive chemicals must be equipped with liquid level, temperature and pressure over-limit alarm facilities, gas leakage detection alarm devices and fire alarm systems ； Key storage tanks such as liquefied gas and highly toxic liquids that constitute major sources of danger must be equipped with emergency cut-off devices. Sinopec An No. 635 (November 17, 2010) "Interim Regulations on Safety and Technical Management of Liquefied Hydrocarbon Spherical Tank Areas of China Petroleum & Chemical Corporation" ◆Setting requirements 3.2.4 Instrument automatic control 3.2.4.1 The liquefied hydrocarbon spherical tank area should be equipped with an instrument control system to complete the data collection, monitoring, alarm and process control tasks of the production process. The control system can use programmable controller (PLC), distributed control system (DCS), supervisory control and data acquisition system (SCADA), field bus control system (FCS), etc. When there are safety interlocking requirements in tank farm operations, safety interlocking loops and safety instrument systems should be set up. Measuring components (including sensors, transmitters, etc.), logic controllers and actuating components (including solenoid valves, control valves, shut-off valves, etc.) in the safety interlock loop should all meet safety integrity level (SIL) requirements. 3.2.4.3 Liquefied hydrocarbon spherical tanks should be equipped with local and remote liquid level gauges. The local liquid level gauge can be a magnetic flap liquid level gauge, a steel strip liquid level gauge, a radar or a servo liquid level gauge, and a tankside indicator. Glass tube (plate) liquid level gauges should not be used. When the local liquid level gauge uses a radar or servo tank side indicator, the spherical tank should also be equipped with a different type of liquid level remote transmission instrument. ◆Interlocking requirements 3.2.4.4 Liquefied hydrocarbon spherical tanks should be equipped with high and low liquid level alarms and high and high liquid level interlocking measures to cut off the feed. The detection components of the high and high liquid level interlocking should be set independently. Ultrasonic, tuning fork, float or capacitive liquid level switches can be used, and should be combined with the high and high liquid level signals of radar, servo and other remote liquid level meters to form a "two out of three" interlocking to cut off the feed. ◆Setting and interlocking requirements 2 Terminology 2.2 Emergency shut-off valves are installed on the inlet and outlet pipes of spherical tanks and can quickly and tightly close (TSO) in the event of an accident or abnormal situation. The allowable leakage level of the emergency shut-off valve should reach ANSI B16.104 (FCI 70-2) CLASS V or above. The valve should have thermal, manual and remote manual (remote control with handle) closing functions. 3.2.4 Instrument automatic control 3.2.4.4 Liquefied hydrocarbon spherical tanks should be equipped with high and low liquid level alarms and high and high liquid level interlocking measures to cut off the feed. The detection components of the high and high liquid level interlocking should be set independently. Ultrasonic, tuning fork, float or capacitive liquid level switches can be used, and should be combined with the high and high liquid level signals of radar, servo and other remote liquid level meters to form a "two out of three" interlocking to cut off the feed. 3.2.4.5 Emergency shut-off valve a) An emergency shut-off valve should be installed at the liquid phase inlet and outlet of the liquefied hydrocarbon spherical tank. The actuator of the emergency shut-off valve can be pneumatic, hydraulic or electric (pneumatic is preferred). When the actuator of the shut-off valve is a pneumatic actuator, a single-acting cylinder actuator (fail-safe type) should be selected. ； If a pneumatic double-acting cylinder actuator is used, an accident air tank should be equipped. When the actuator is electric, its power supply should be powered by an electrical UPS, and its power cables, signal cables and electric actuators should be fireproof. b) Emergency shut-off valves should be distinguished from process control valves. Its sealing structure should adopt fire-resistant structure and comply with ANSI/API STD607 standard ； The allowable leakage amount should comply with ANSI B16.104 (FCI 70-2) CLASS V or above. c) Emergency shut-off valve interlock buttons should be installed outside the fire embankment of the liquefied hydrocarbon spherical tank area and at the control room operating station (hard switch or soft switch). When the liquid level in the spherical tank reaches a high alarm or a fire occurs, the operator can close the emergency shut-off valve remotely or manually on site. After the emergency shut-off valve is closed, the feed pump will be automatically interlocked to stop. The closing time of the emergency shut-off valve is as follows:: __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Nominal size DN (mm) Full closing time (s) __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ≤50 ≤5 65~350 ≤10 __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ d) The emergency shut-off valve should be able to ensure that it automatically closes when the temperature of the fusible component automatic shut-off device reaches 75±5°C. e) The selected emergency shut-off valve should be a fail-safe type. "Sinopec Liquefied Hydrocarbon Spherical Tank Area Safety and Technical Management Regulations" ◆Setup Requirements: 4.4 Instrument automatic control 4.4.1 The liquefied hydrocarbon spherical tank area should be equipped with an instrument control system to complete the data collection, monitoring, alarm and process control tasks of the production process. The control system can use programmable controller (PLC), distributed control system (DCS), supervisory control and data acquisition system (SCADA), field bus control system (FCS), etc. 4.4.3 Liquefied hydrocarbon spherical tanks should be equipped with local and remote liquid level gauges. The local level gauge can be a magnetic flap level gauge, steel strip level gauge, radar or servo level gauge tankside indicator. When the local liquid level gauge uses a radar or servo tank side indicator, the spherical tank should also be equipped with a different type of liquid level remote transmission instrument. ◆Interlocking requirements 4.4.4 Liquefied hydrocarbon spherical tanks should be equipped with high and low liquid level alarms and high and high liquid level interlocking measures to cut off the feed. The detection components of high and high liquid level interlocking should be set independently, and can use ultrasonic, tuning fork, float, capacitive liquid level switch, etc. ◆Set requirements 4.4.5.4 The emergency shut-off valve should be controlled remotely from the control room and locally on site. Its closing time is as follows:: __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Nominal size DN (mm) Full closing time (s) __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ≤50 ≤5 65~350 ≤10 __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Sinopec Construction No. 518 "Regulations on Selection and Design of Emergency Shutoff Valve for Liquefied Hydrocarbon Spherical Tanks" ◆Setting requirements 3.1 Emergency shutoff valve is a switch valve specially designed to be installed on the inlet and outlet pipelines of liquefied hydrocarbon spherical tanks. It can quickly and tightly cut off (TSO) and isolate flammable and toxic materials when fire, leakage and other accidents occur in the tank area. When the liquid level of the spherical tank reaches or exceeds the high liquid level limit, the emergency shut-off valve can be used to prevent materials from overflowing. Except for pipes, no other pipe fittings or valves shall be installed between the emergency shut-off valve and the spherical tank nozzle. The spacing shall comply with the requirements of piping installation, valve maintenance and process requirements. The emergency shut-off valve should have automatic and manual closing functions. The manual closing function should include remote manual closing in the control room and manual closing on site. 4.5.11 An on-site operation switch for the emergency shut-off valve should be installed outside the fire danger area of the liquefied hydrocarbon spherical tank area. Its contact signal is directly sent to the solenoid valve of the pneumatic actuator or the ESD action terminal of the electro-hydraulic or electric actuator, which is used to manually close the emergency shut-off valve on site in an emergency. (November 20, 2018) Sinopec Anfei No. 477 "Guiding Opinions on the Rectification of Flammable and Combustible Liquid Atmospheric Storage Tank Areas of Sinopec" ◆Interlocking requirement 4.1.4 The emergency shut-off valve on the tank feed pipe should be interlocked with the tank high and high liquid level alarm instrument ； Setup and interlocking requirements: 4.1 Emergency shut-off valve settings 4.1.1 Emergency shut-off valves should be installed on storage tanks that store extremely hazardous liquids (Level I) and highly hazardous liquids (Level II), Class A B and B A flammable liquid storage tanks with a capacity greater than or equal to 3000m3, other flammable liquid storage tanks with a capacity greater than or equal to 10000m3, and storage tanks that constitute primary and secondary major hazard sources. The emergency shut-off valve should be able to be remotely controlled from the control room. 4.1.2 Emergency shut-off valves for storage tanks in refineries, petrochemical plants, and petrochemical fiber plants should use pneumatic valves and should have a fault shut-off function. ； Electric valves can be used as emergency shut-off valves for crude oil depots, refined oil depots, and storage tanks at stations affiliated with oil pipelines. 4.1.3 The emergency shut-off valve on the inlet and outlet pipe of the storage tank can be shared with the process control valve. 4.1.4 The emergency shut-off valve on the tank feed pipe should be interlocked with the tank high and high liquid level alarm instrument. 4.1.8 The time for the emergency shut-off valve to be fully open or fully closed through a pneumatic or electric actuator shall not exceed 180 seconds. 4.2.1 Storage tanks for benzene, liquefied hydrocarbons, and liquid ammonia should be equipped with independent safety instrumented systems (Safety Instrumented System - SIS). [Free to attend] Lanzhou August 31 - 2023 Microchemical and Microreactor Technology Exchange Seminar Notice No. 39: Sinopec's "Guiding Opinions on Rectification and Rectification of Hidden Hazards in Tank Areas" ◆Setting and interlocking requirements: 4. Low and low liquid level interlocking, high and high liquid level interlocking 1. Storage tanks with a volume greater than 100m3 should be equipped with remote transmission instrument components for continuous liquid level measurement of high, high, high, low and low liquid levels. However, whether the high, high and low liquid levels are interlocked to cut off the inlet and outlet valves or stop the pump needs to consider the impact of the interlocking and should comply with the following regulations.: (1) Any storage tank that is a primary or secondary major hazard source should be equipped with a high-high liquid level interlock to close the feed valve, and it should be verified whether the design pressure of the tank inlet pipeline and its related pipelines meets the requirements of the most demanding working conditions (such as the dead center lift of the pump, etc.) and whether the safety measures are complete. (2) When a high liquid level interlock of a storage tank for a certain material closes the feed valve, in order not to affect the normal production of the upstream device (facility), an alarm should be raised and the feed valve of the other storage tank should be opened quickly. (3) When the low liquid level of the storage tank is set to automatically interlock and stop the pump, which will cause major impacts such as shutdown and restart of downstream equipment or stations (such as equipment raw material tanks, intermediate raw material tanks, and primary oil station storage tanks), when the liquid level is low, a secondary alarm should be used, the interlock closes the discharge valve, and the alarm switches to open the discharge valve of another storage tank. (4) When the low liquid level of the storage tank is set to automatically interlock and stop the pump, the storage tank (such as the finished product storage tank of the refining and chemical enterprise, the storage tank of the refined oil depot) that will not have a major impact on downstream operations (loading, shipping) such as shutdown and restart, can adopt an interlock to close the discharge valve or interlock to stop the pump when the liquid level is low. ◆Setting and interlocking requirements 2. For storage tanks belonging to primary or secondary major hazard sources, in addition to setting high and low liquid level alarms, corresponding alarms and linkage protection measures should also be set for low and low liquid levels and high and high liquid levels. For storage tanks that need to be equipped with an independent SIS system, the tank root valve on the inlet and outlet pipelines (the emergency shut-off valve must take fire prevention measures, have manual operation functions, and take fire prevention measures), use the SIS system interlock to cut off the feed in emergency situations such as high liquid levels in the storage tank, fire accidents, etc. ； For storage tanks that do not need to be equipped with an independent SIS system, the tank root valves on the inlet and outlet pipelines should use control valves and should have manual operation functions. In emergencies such as high liquid levels in the storage tanks and fire accidents, the feed can be cut off through interlocking of the basic process control system. Q/SH 0749-2018 "Technical Standards for Liquefied Hydrocarbon Storage and Transportation Engineering" ◆Setting and interlocking requirements 12.2.5 The selection of level instruments should comply with the following regulations: a) Low-temperature vertical storage tanks should be equipped with two servo level gauges for liquid level measurement ； Low-temperature vertical storage tanks should be equipped with an additional servo liquid level gauge to interlock the high and low liquid level with the liquid level alarm signals of the two servo liquid level gauges mentioned above. b) The spherical tank should be equipped with a servo level gauge and a radar level gauge respectively for liquid level measurement. An additional liquid level switch should be set up to perform high-high liquid level interlocking with the liquid level alarm signals of the above two liquid level gauges. ； Another liquid level switch is set up to perform low and low liquid level interlocking with the liquid level alarm signals of two liquid level gauges. f) Emergency shut-off valve (ESDV) should use pneumatic single-acting actuator or electro-hydraulic actuator. g) The selection of the emergency shut-off valve at the root of the liquefied hydrocarbon spherical tank should comply with Sinopec Construction No. 518 "Regulations on Selection and Design of Emergency Shut-off Valve for Liquefied Hydrocarbon Spherical Tanks" ； The fire cover of the emergency shut-off valve at the root of the spherical tank should be a rigid fire protection cover suitable for outdoor open-air situations. The fire protection cover should be able to ensure that its internal temperature is below 80°C within 30 minutes under a 1093°C hydrocarbon fire. Letter No. 27 from the General Office of Work Safety * * General Office of the State Administration of Work Safety (February 7, 2018) ◆Setting and interlocking requirements: (1) Jiangsu Tianjiayi Chemical Co., Ltd. (13 items) 5. The DCS and SIS pressure transmitters of some dinitrification reactors share a pressure tapping point. 6. The benzene tank area and the methanol tank area that constitute secondary major hazard sources are not equipped with emergency shut-off valves at the root of the tank. 8. The cabinet room and monitoring room are illegally set up in the nitrification plant. (2) Xiangshui County Kunpeng Chemical Co., Ltd. (15 items) 6. The fractionation system does not realize automatic control. 11. The doors and windows of the control room and cabinet rooms face devices with fire and explosion hazards. 12. The ESD system does not have dual-circuit power supply. (3) Jiangsu Dahua Chemical Industry Co., Ltd. (11 items) 4. The DCS control room of the installation is a non-explosion-proof structure, and the doors and windows face the No. 1 production workshop with fire and explosion risks. 8. The tank area that constitutes a major first-level hazard source is not equipped with an emergency shut-off valve at the root of the tank. 9. The instrument interlock was removed without completing the relevant procedures. (4) Jiangsu Yongtai Technology Co., Ltd. (9 items) 3. The tank area that constitutes a first-level major hazard source has many safety hazards, such as the emergency shut-off valve is not set at the root of the storage tank. ； The storage tanks are not equipped with on-site liquid level indicators, and some storage tanks are only equipped with one electrostatic grounding point. ； (2) Jiangsu Sirbon Petrochemical Co., Ltd. (9 items) 4. The interlocking machine pump at the installation site did not indicate interlocking in a conspicuous position on the coupling protective cover. 7. The gland openings of some instrument junction boxes are not sealed and are not explosion-proof. ； The electrostatic jumpers on some instrument bodies and junction boxes fell off. (3) Jiangsu Helirui Technology Development Co., Ltd. (17 items) 8. There is no emergency shutdown system for devices involving hazardous chemical processes under key supervision. 17. The control room is located in the production device. (4) Jiangsu Xincheng Chemical Co., Ltd. (13 items) 6. The equipment involved in hazardous chemical processes under key supervision did not realize automated control or emergency shutdown. (1) Jiangsu Zhongneng Silicon Industry Development Co., Ltd. (12 items) 3. The management and control measures for major hazard sources are incomplete. If the enterprise constitutes a first-level major hazard source, the permissible social risk curve evaluated in the status evaluation report falls in the lowest possible area, and the existing potential risks are not analyzed and the relevant risk treatment measures are not formulated and implemented as required. 7. The safety instrument system is imperfect. For example, devices involving hazardous chemical processes do not have an emergency shutdown system that is independent of the process control system as required. Work Safety Supervisor No. 3 No. 121 "Standards for the Determination of Major Production Safety Accidents in Chemical and Hazardous Chemical Production and Operation Units (Trial)" ◆ Setup and interlocking requirements 4. Devices involved in key supervision of dangerous chemical processes have not implemented automatic control, the system has not implemented the emergency stop function, and the equipment's automated control system and emergency stop system have not been put into use. 5. The hazardous chemical tank area that constitutes the primary and secondary major hazard sources does not implement the emergency cut-off function. ； Hazardous chemical tank areas involving primary and secondary major hazard sources of toxic gases, liquefied gases, and highly toxic liquids are not equipped with independent safety instrument systems. 10. The chemical equipment in service has not been formally designed and safety design diagnosis has not been carried out. 13. The side of the control room or cabinet room facing the equipment with fire or explosion risk does not meet the requirements. * * Standard requirements for fire and explosion protection. 14. Chemical production equipment failed to operate * * The standard requires dual power supply, and the automatic control system does not have an uninterruptible power supply. 19. The newly developed production process of hazardous chemicals shall be directly put into industrial production without small-scale, pilot-scale or industrial tests. ； The chemical process used for the first time in China has not passed the provincial people’s * * Safety and reliability demonstration organized by relevant departments ； The newly-built device was put into operation without formulating a trial production plan. ； Fine chemical companies failed to conduct reaction safety risk assessments in accordance with the requirements of normative documents. Notice of the General Administration of Work Safety No. 3 No. 68 on further strengthening the safety management of chemical tank areas ◆ Setup and interlocking requirements (1) Further improve the monitoring and control facilities of chemical tank areas. Set up high and low liquid level alarms for storage tanks in accordance with regulatory requirements, and use ultra-high liquid level automatic interlocking to close the tank feed valve and ultra-low liquid level automatic interlocking to stop material transportation. Ensure that the flammable, explosive, toxic and harmful gas leakage alarm system is intact and available. Emergency shut-off valves should be installed in key storage tanks such as large, liquefied gas and highly toxic chemicals. (2) Strengthen the production and operation management of chemical tank areas. During normal operation, it is strictly forbidden to form a space between the floating plate of the inner floating roof tank and the material. Under special circumstances, when ultra-low liquid level operation is required, when resuming feeding, ensure that the feed flow rate is less than the limited flow rate to prevent static electricity from causing accidents. When a liquid level alarm occurs, immediate measures must be taken. (6) Tank areas involving key regulated hazardous chemicals must conduct regular hazard and operability analysis. Guiding Opinions of the General Administration of Work Safety on Strengthening Chemical Process Safety Management No. 388 (July 29, 2013) ◆ Setup and interlocking requirements (5) Establish a risk management system. Enterprises must formulate a chemical process risk management system, clarify the scope, methods, frequency and responsible persons of risk identification, stipulate the requirements for the application of risk analysis results and the implementation of improvement measures, and conduct risk identification and analysis of the entire production process. Risk identification and analysis of production and storage devices involving key supervised hazardous chemicals, key supervised hazardous chemical processes and major hazard sources of hazardous chemicals (hereinafter collectively referred to as "two key points and one major") must use hazard and operability analysis (HAZOP) technology, which is generally conducted every three years. For risk identification analysis of other production storage devices, according to the different complexity of the device, methods such as safety checklist, work hazard analysis, pre-hazard analysis, failure type and impact analysis (FMEA), HAZOP technology, etc. or a combination of methods are selected, and can be conducted once every 5 years. When there are major changes in the enterprise's management structure, personnel composition, production equipment, etc. or when a production safety accident occurs, risk identification and analysis must be carried out in a timely manner. Enterprises must organize all personnel to participate in risk identification and analysis, and strive to have full coverage of risk identification and analysis. (7) Establish acceptable risk standards. Enterprises must comply with the "Interim Provisions on the Supervision and Management of Major Hazardous Sources of Hazardous Chemicals" ( * * According to the requirements of the State Administration of Work Safety Order No. 40), * * Relevant regulations or with reference to relevant international standards, determine the risk standards acceptable to the enterprise. For unacceptable risks discovered through identification and analysis, enterprises must promptly formulate and implement measures to eliminate, reduce or control the risks to control the risks within an acceptable range. Su Emergency No. 53 Notice of the Provincial Emergency Management Department on the issuance of the "Basic Requirements for Intrinsic Safety Diagnosis and Management" issued by the Office of the Jiangsu Provincial Emergency Management Department on June 6, 2019 ◆ Setup and interlocking requirements 1. Diagnosis of major hidden dangers is in accordance with the "Standards for the Determination of Major Production Safety Accident Hazards in Chemical and Hazardous Chemicals Production and Operation Units (Trial)" (Work Safety Supervisor 3 [2017] No. 121), and strict identification of major hidden dangers without omissions or misjudgments. 5. According to " * * Notice of the State Administration of Work Safety on the Announcement of the First Batch Catalog of Hazardous Chemical Processes under Key Supervision (Work Safety Supervision Manager III [2009] No. 116), " * * Notice of the State Administration of Work Safety on the publication of the second batch of catalogs of hazardous chemical processes under key supervision and the adjustment of some typical processes in the first batch of hazardous chemical processes under key supervision (Safety Supervision General Manager 3 [2013] No. 3), GB/T50770, GB/T20438, GB/T21109 and other regulations, and in accordance with HAZOP Analyze the recommended items, list and diagnose the compliance with the safety functions of automatic control of hazardous chemical process production equipment (including DCS, PLC, ESD, SIS) that are under key supervision, and list the non-conforming items item by item. 6. In accordance with the "Interim Provisions on the Supervision and Management of Major Hazardous Sources of Hazardous Chemicals" (formerly * * Order No. 40 of the State Administration of Work Safety), " * * Documents such as the "Guiding Opinions of the State Administration of Work Safety on Strengthening the Management of Chemical Safety Instrument Systems" (Work Safety Supervisor III [2014] No. 116) require that the compliance of safety functions such as automated control, safety instrument systems, emergency stop systems or emergency cut-off facilities of production devices (storage facilities) that constitute major hazard sources be listed and diagnosed, and non-conformities be listed item by item. (1) Automatic control of raw material, product storage tanks and equipment storage tanks 1. Flammable liquid storage tanks, toxic liquid storage tanks, cryogenic storage tanks and pressure tanks with a volume of 100m3 or more should be equipped with remote instrument components for continuous liquid level measurement and local liquid level indication, and should be equipped with high liquid level alarms. Floating roof storage tanks and storage tanks with pumps should also be equipped with low liquid level alarms. ； The pressure tank for flammable and toxic media is equipped with a high liquid level or high pressure interlock to stop feeding. If the design plan or HAZOP analysis report requires setting up low and low liquid level automatic interlocking to stop the pump and cut off the discharge valve, these requirements should be met. 2. Liquid raw material and finished product storage tanks involving 16 types of inherently explosive and dangerous chemicals with a volume of less than 100m3 should be equipped with high liquid level alarms. If the design plan or HAZOP analysis report requires setting up high and high liquid level alarms and interlocking to cut off the feed valve, and low and low liquid level alarms and interlocking to lock and stop the pump, these requirements should be met. 3. Storage tanks for Class I and Class II toxic liquids, storage tanks for Class A B and Class B A flammable liquids with a capacity greater than or equal to 1000m3, and other flammable liquid storage tanks with a capacity greater than or equal to 3000m3 should be equipped with high and high liquid level alarms and interlocking closing tank inlet pipeline control valves. 4. Liquid storage tanks constituting Class I or II major hazardous chemical tank areas should be equipped with high and low liquid level alarms and high and low liquid level interlocking emergency cut-off inlet and outlet pipeline control valves. 5. Storage tanks for flammable liquids or toxic liquids should be equipped with high liquid level alarms and high and high liquid level interlocks to cut off the feed. The high-level tank of the device should be equipped with a high-liquid-level alarm and high- and high-liquid-level interlocking to cut off the feed or set up an overflow pipe. It is advisable to set up low- and low-liquid level interlocking to stop the pump or cut off the discharging facilities. 7. Hazardous chemical tank areas involving primary and secondary major hazard sources of toxic gases, liquefied gases, and highly toxic liquids should be equipped with independent safety instrument systems. The detection components and actuators of each circuit should be set independently, and the safety instrument level (SIL) should be no less than level 2. 9. Flammable liquid and highly toxic liquid storage tanks with high liquid level interlocking function should be equipped with liquid level gauges or liquid level switches with two different principles. The high liquid level interlocking measuring instrument and the basic control loop liquid level gauge should be set up separately. The pressure storage tank liquid level measurement should be equipped with a set of remote transmission instruments and local indicating instruments, and another set of liquid level measuring instruments or liquid level switches dedicated to high and high liquid level or low and low liquid level alarms and interlocking to cut off the tank feed (discharge) valve. 14. Major hazard sources that constitute Class I and Class II hazardous chemicals should be equipped with emergency shutdown systems, and emergency cut-off devices should be set up for key facilities such as toxic gases, highly toxic liquids, and flammable gases in major hazard sources. The safety function of the emergency stop (emergency cut-off) system can be implemented either through a basic process control (DCS or SCADA) system or through a safety instrumented system (SIS). For safety integrity (SIL) level 1, the safety function of the emergency stop (emergency cut-off) system can be realized through the basic process control (DCS or SCADA) system or through a safety instrumented system (SIS). For safety integrity (SIL) level 2 and above, the emergency stop function must be realized through a safety instrumented system (SIS). Notice No. 88 of the General Office of the State Council on Issuing the Comprehensive Safety Management Plan for Hazardous Chemicals ◆ Setup and interlocking requirements: (1) Chemical safety instrumented system (SIS) includes safety interlocking system, emergency shutdown system, toxic and harmful, flammable gas and fire detection and protection system, etc. The safety instrumented system is independent of the process control system (such as a decentralized control system, etc.) and is in a dormant or static state during normal production. Once a situation occurs in a production device or facility that may lead to a safety accident, it can act instantly and accurately to stop the production process safely or automatically enter a predetermined safety state. It must have high reliability (i.e. functional safety) and standardized maintenance and management. According to the consequences and risks of safety instrument function failure, safety instrument functions are divided into different safety integrity levels (SIL1-4, the highest is level 4). Different levels of safety instrumented circuits have different technical requirements in terms of design, manufacturing, installation and commissioning, and operation and maintenance. (11) Design and implement toxic, harmful and flammable gas detection and protection systems in strict accordance with relevant standards. To ensure reliable functions, the relevant systems should be independent of the basic process control system. (12) Starting from January 1, 2016, qualified chemical enterprises such as large-scale and foreign-owned joint ventures that build new chemical plants and hazardous chemical storage facilities involving "two priorities and one major" must design safety instrument systems that comply with relevant standards in accordance with the requirements of this guidance. (13) Starting from January 1, 2018, all newly built chemical plants and hazardous chemical storage facilities involving “two key points and one major” must be designed with safety instrument systems that meet the requirements. Safety instrument systems for other newly built chemical plants and hazardous chemical storage facilities should implement functional safety-related standard requirements from January 1, 2020, and design safety instrument systems that meet the requirements. (14) Chemical enterprises and hazardous chemical storage units involving "two key points and one major" in-service production devices or facilities must, on the basis of comprehensively carrying out process hazard analysis (such as hazard and operability analysis), determine the safety instrument functions and their risk reduction requirements through risk analysis, and evaluate as soon as possible whether the existing safety instrument functions meet the risk reduction requirements. (15) Enterprises should formulate safety instrument system management plans and regular inspection and testing plans based on evaluation. For safety instrument functions that do not meet the requirements, relevant maintenance plans and rectification plans should be formulated, and the safety instrument system evaluation and improvement work should be completed by the end of 2019. Other chemical equipment and hazardous chemical storage facilities must refer to the requirements of this opinion. Safety Supervision Manager No. 3 No. 113 * * Notice of the State Administration of Work Safety on Issuing the "Key Guidance Catalog for Safety Inspection of Chemical (Hazardous Chemicals) Enterprises" ◆ Setup and interlocking requirements ◆ Equipment and facility management 19. Oil and gas storage tanks fail to meet the following requirements as required: (1) Liquefied hydrocarbon storage tanks should be equipped with liquid level gauges, thermometers, pressure gauges, safety valves, as well as high liquid level alarms and high and high liquid level automatic chain feed cutoff measures. ； Fully refrigerated liquefied hydrocarbon storage tanks should also be equipped with vacuum relief facilities and high and low temperature detection, and should be connected to the automatic control system ； (2) The gas cabinet should be equipped with upper and lower limit alarm devices, and an automatic interlocking and cutting device for the inlet and outlet pipes should be installed ； (3) The liquid phase inlet and outlet of the liquefied petroleum balloon storage tank should be equipped with an emergency shut-off valve, and its location should be close to the spherical storage tank. ； (4) Water injection measures should be provided for spherical storage tanks of propylene, propane, mixed C4, residual C4 and liquefied petroleum gas. Article 33 of the Production Safety Law ； Articles 6.3.11 and 6.3.12 of "Code for Fire Protection Design of Petrochemical Enterprises" (GB50160) ； "Safety Design Code for Liquefied Hydrocarbon Spherical Tanks" (SH3136) Articles 6.1 and 7.4 ； 20. Devices involving hazardous chemical processes and hazardous chemicals under key supervision are not equipped with automated control systems. ； Or large chemical plants involving hazardous chemical processes are not equipped with emergency shutdown systems. "Measures for the Implementation of Safety Production Licenses for Hazardous Chemical Production Enterprises" ( * * Article 9 of the Order No. 41 of the State Administration of Work Safety. 25. Dangerous chemical process production equipment involving exothermic reactions is not equipped with dual power supplies or the control system is not equipped with an uninterruptible power supply (UPS). Article 38 of the "Safety Production Law", "Technical Specifications for Electric Power Design of Production Equipment of Petrochemical Enterprises" (SH3038), "Design Specifications for Power Supply and Distribution Systems" (GB50052). ◆Safety Management 28. The control room or cabinet room has doors and windows on the side facing the device with fire or explosion risk. (Rectification must be completed before 2017) ； Article 38 of the Safety Production Law and Article 5.2.18 of the "Code for Fire Protection Design of Petrochemical Enterprises" (GB50160). API STD 2510-2011 Design and Construction of LPG Installations ◆Setup and interlocking requirements 9.3.4 Emergency Shutoff Valves 9.3.4.1 Emergency shutoff valves shall be provided in the loading-unloading system for tank cars, trucks, and marine facilities and shall incorporate the following means of closing: a. Manual shutoff at the installed location. b. Manual activation from a location accessible during an emergency. A safety analysis shall be the basis for determining the need for the following: a. Automatic shutoff in the event of an LPG release. b. Automatic shutoff through thermal (Tre) actuation. 9.3.4.2 Installation practices for emergency shutoff valves shall include those specified in 9.3.4.2 .1 and 9.3.4.2 .2. 9.3.4.2 .1 When hose or swivel piping is used for liquid or vapor transfer, an emergency shutoff valve shall be installed in the Txed piping of the transfer system within 20 linear ft of pipe from the end to which the hose or swivel piping is connected. Where the ßow is in one direction only, a check-valve may be used in place of an emergency shutoff valve if the check valve is installed in a dedicated storage vessel Tll line or vapor return line. When two or more hoses or swivel piping arrangements are used, either an emergency shutoff valve or a check-valve (for unloading lines only) shall be installed in each leg of the piping. Note: If check valves are used in place of emergency shutoff valves, the owner/operator should have a program to assure the reliability of these devices. 9.3.4.2 .2 The emergency shutoff valves or backßow check valves shall be installed in the Txed piping so that any break resulting from a pull will occur on the hose or swivel piping side of the connection while the valves and piping on the plant side of the connection remain intact. This may be accomplished by the use of concrete bulkheads or equivalent anchorage or by the use of a weakness or shear Ttting. Refer to NPGA Bulletin 128. API RP 2001-2012 Fire Protection in Refineries ◆Setup and interlocking requirements: 5.4.3.4 Isolation Valves 5.4.3.4 .1 General A key consideration for isolation valves is being able to isolate sections of process to minimize the quantity of hydrocarbons released and prevent influx of additional material from other areas. Isolation valves should be provided at unit boundaries or within process unit areas to isolate equipment during fire situations. Consideration should be given to safe access and the ability to physically operate manually operated valves during fire conditions or in emergency situations. Where possible, battery limit valves should be spaced sufficiently far from process equipment fire hazardous areas to allow safe manual actuation. If located inside fire hazard areas, valves may need to be capable of remote operation. Isolation valves can also permit blinding for maintenance and inspection. During blinding operations, blinds suitable for equipment-rated pressure should be installed. Isolation valves and drains should be provided for equipment that may be opened or removed during repair operations. See API 553. 5.4.3.4 .2 Remotely Operated Valves Where a review establishes a need, remotely operated shutoff valves (ROSOV) should be considered during the PHA and FHA processes. Use of these and other isolation valves should be included in emergency procedures. However, use of automatic (fire or heat actuated) self-closing valves should be used only after a hazard analysis or MOC review to determine whether inadvertent activation may cause undesired consequences. This review should confirm that the automatic valve system is inherently safe by a rigorous process safety review since closure of the valve in a nonfire situation or at the wrong time in a fire event may have undesirable consequences, such as causing excessive pressure in a process system or preventing the orderly shutdown sequence of equipment or transfer of product from tanks or vessels during an emergency. The review should include a determination of the safest alternative (“open” or “closed”) on loss of power if ROSOV are used. Discussion of emergency valves (ROEIV, EIV, EBV, ROSOV) can be found in API 553 and UK HES Information Sheet CHIS2. API 553 -2012 Refinery Valves and Accessories for Control and Safety Instrumented Systems ◆Setting and interlocking requirements 3.9 emergency block valves EBVs Emergency block valves are designed to control a hazardous incident. These are valves for emergency isolation and are designed to stop the uncontrolled release of flammable or to * c materials. These valves should be fire-safe, if they are within the fire zone. The valves may be referred to as type A, B, C, and D. Refer to their individual definitions within this section. 3.14 fire zone This is an area which is unsafe to enter during an emergency situation. The area is considered to be within a 7.6 m (25 ft) radius minimum surrounding the leak source. 3.43 Type A EBV A manually operated fire-safe block valve installed at the equipment. This type of valve is installed when ignition is not expected in the event of a leak. 3.44 Type B EBV This fire-safe block valve should be installed at a minimum of 7.6 m (25 ft) from the leak source when ignition is expected. 3.45 Type C EBV The Type B valve is a power-operated Type B valve. The valve should be power-operated if larger than DN 200 (8 in.) or if a pressure class higher than ANSI CL300 is needed. The valve should be installed outside the fire zone a minimum of 7.6 m (25 ft) from the leak source and no higher than 4.6 m (15 ft) above grade. Controls are accessible from the valve location. 3.46 Type D EBV This is an EBV with remote controls. There is no restriction as to where the valve may be located, but the controls should be a minimum of 12 m (40 ft) from the leak source and should be out of the fire zone. An EBV installed at an elevation greater than 4.6 m (15 ft) above grade will also come under this category. Both the actuator and that portion of the control cable and tubing which is in the fire zone should be fireproofed or designed to operate without failure during fire conditions. Specify that the conduit/tubing/cable supports are required to be fireproofed.