Explanations on relevant regulations and standards regarding the first-level power consumption load for hazardous chemical enterprises

Thread Content

This post was last edited by cww9521 on 2023-7-2 at 10:20. I. Electrical load for fire pumps and fire protection systems: Chapter 9 Electrical Systems of GB50160-2008 \"Code for Fire Protection Design of Petrochemical Enterprises\", 9.1 Fire power supplies, power distribution, and general requirements; 9.1.1 The electrical load for fire pump rooms in large and medium-sized petrochemical enterprises should be classified as a Class 1 load. Chapter 9 Fire Protection Facilities of GB 51283-2020 \"Fire Protection Design Code for Fine Chemical Enterprises\", section 9.3 Fire Water Supply: Article 9.3.7 The power supply for fire pumps shall comply with the following requirements: 2 Factories (warehouses), storage tank areas, etc., where the designed outdoor fire water flow rate is greater than 25 L/S, shall be equipped with two power sources ； 3 Fire pumps equipped with automatic sprinkler systems or fixed foam fire extinguishing systems shall be provided with two independent power sources: they should be powered by primary power supply, or diesel pumps should be used for the backup pumps. GB 51283-2020 \"Code for Fire Protection Design of Fine Chemical Enterprise Engineering\" Chapter 11 Electrical Systems 11.1 Fire Power Supplies and Distribution 11.1.1 The power supplies for fire pumps, fire elevators, smoke control and exhaust systems, automatic fire alarm systems, automatic fire extinguishing systems, emergency lighting and evacuation signs, as well as electric fire doors, windows, fire shutters, valves and other fire-related electrical equipment, shall comply with the following provisions: 1 The power supply requirements for fire pumps shall be in accordance with Article 9.3.7 of this standard. 2. The other fire protection electrical loads of the following buildings, storage tanks (areas), and stockyards, other than fire pumps, shall be supplied with power as secondary load: 1) Factories and warehouses with an outdoor fire water demand greater than 30 L/s ； 2) Open-air production facility areas with an outdoor fire water demand of more than 35 L/s, combustible material storage yards, combustible gas storage tanks (areas), and storage tanks (areas) for Class A and B liquids. 3 Fire power supplies for different load levels shall comply with the relevant provisions of the current **standard, the “Code for Design of Power Supply and Distribution Systems” GB50052. 11.1.2 For the power supply of important low-voltage fire protection equipment in the fire control room, such as fire protection electrical equipment, fire pumps and foam fire pumps, smoke prevention and exhaust fans, fire elevators, etc., a dual-power automatic switching device should be installed at their lowest-level power distribution unit or distribution box. In accordance with Chapter 11 Electrical Systems, 11.1 Fire Power Supplies and Power Distribution, Article 11.1.2 of GB 51283-2020, and in line with the relevant provisions of GB50052-2009 \"Code for Design of Power Supply and Distribution Systems\" and GB50160-2008 \"Fire Protection Code for Petrochemical Enterprises\", the gas detection system, emergency lighting, DCS system, SIS system, and GDS system are classified as particularly important loads within the first-level load category ； Fire protection equipment (fire pumps and related pumps, smoke exhaust systems, emergency fans, fire alarms, etc.) falls under category 1 load. In summary, it is now clear whether fire protection facilities should be classified as first-class loads. II. Power load for combustible gas and toxic gas detection and alarm systems: According to GB/T 50493-2019, the Design Standard for Combustible Gas and Toxic Gas Detection and Alarm Systems in the petrochemical industry, clause 3.0.9 states that the power supply requirements for gas detectors, alarm control units, on-site alarms, etc., in such systems should be treated as those of particularly important loads within the category of first-class power loads; it is advisable to use UPS power supply units for these devices. In other words, combustible gas and toxic gas detection and alarm systems belong to the first-class power load, and are particularly important loads among those in the first-class category. III. Calculation of electrical load for basic process control systems and safety instrumented systems – Refer to HG/T 20509-2014, Code for Design of Instrument Power Supply. 3. Scope of instrument power supply, load categories, and power source types. 3.1 Scope of power supply. 3.1.1 The power supply for measuring and control instruments shall include the following: 1. Measuring instruments, actuators, and conventional monitoring instruments ； 2 Systems such as DCS, FCS, PLC, and monitoring computers ； (Basic Process Control Systems) 3 Online Analytical Instrument Systems ； 4 SIS; (Safety Instrumented System) 5 Flammable and toxic gas detection and alarm system ； 6 CCS.3.1.2 The power supply for instrument auxiliary facilities shall include lighting and sockets inside the instrument panel (cabinet). 3.2 Load Classes and Power Source Types 3.2.1 The classification of instrument power load classes shall comply with the relevant provisions of the current **standard \"Code for Design of Power Supply and Distribution Systems\" GB 50052-2009. Instrument power loads can be divided into two classes: particularly important loads belonging to Class I loads, and Class III loads. 3.2.2 The operating power supply for instruments can be divided into UPS and conventional power supplies, depending on the power load requirements of the instruments. 3.2.3 When the power load for instruments belongs to the particularly important category among primary loads, a UPS should be used ； When the instrument power load belongs to category III load, a regular power supply can be used. In summary, DCS, SIS, and GDS systems are considered particularly important loads among the first-class loads, and should be powered by UPS. IV. Article 25 of the \"Key Guidelines for Safety Inspections of Chemical (Hazardous Chemicals) Enterprises\" (Document No. An Jian Zong Guan San [2015] 113) addresses cases where hazardous chemical processing units involving exothermic reactions do not have dual power supplies, or where the control systems lack uninterruptible power supply (UPS). As a particularly important load among the first-class loads, the control system should be powered by a UPS, whereas the UPS’s input power source has not yet been classified as a first-class load. Although there is a “or” word in Article 25, the former involves providing dual power supplies for the production equipment (mechanical devices), while the latter refers to the lack of an uninterruptible power supply for the control system (power supply for the low-voltage system cabinets); in fact, these are two different approaches. For example: if there is a power outage, the control system still has a UPS to supply power, but the drive equipment of the hazardous chemical processing units that involve exothermic reactions loses power, as do refrigerant transfer pumps and similar devices. With only the control system having power, operators can do little more than observe the situation in an emergency caused by such a power outage. V. “Notice of the Provincial Emergency Management Department on Issuing the <Acceptance Criteria for the Full-Process Automation Control Transformation of Key Chemical Enterprises in Jiangsu Province (Trial)>” (Su Ying Ji [2021] No. 48, Annex 1). Article 11 of the full-process acceptance form in Annex 1 states that “the emergency response systems for toxic gases that are in standby mode should be equipped with remote and local one-click start functions; backup pumps should be provided for the absorbent supply pumps and absorbent circulation pumps, and these backup pumps should have the capability to start automatically when low pressure or low flow rates are detected. The electrical load associated with these systems should be classified as a level-1 load.” ” The above is for reference only. Automatic control instruments