Precautions for operating a floating roof tank at low liquid level

**Notice from the General Administration of Work Safety on the Issuance of the “Ten Provisions for Chemical (Hazardous Chemicals) Enterprises to Ensure Production Safety”, the “Ten Provisions for Fireworks and Firecrackers Enterprises to Ensure Production Safety”, and the “Ten Provisions for Fire and Explosion Prevention in Oil and Gas Storage Areas” – GAWS Political and Legal Affairs [2017] No. 15: To the work safety supervision bureaus of all provinces, autonomous regions, municipalities directly under the Central Government, and the Xinjiang Production and Construction Corps: The “Ten Provisions for Chemical (Hazardous Chemicals) Enterprises to Ensure Production Safety”, the “Ten Provisions for Fireworks and Firecrackers Enterprises to Ensure Production Safety”, and the “Ten Provisions for Fire and Explosion Prevention in Oil and Gas Storage Areas” are hereby issued to you; please ensure their strict implementation. **State Administration of Work Safety, March 6, 2017 – Ten Provisions for Chemical (Hazardous Chemicals) Enterprises to Ensure Production Safety. 1. Enterprises must be established in accordance with the law, and must possess all necessary licenses and permits that are valid. II. It is necessary to establish and improve a comprehensive safety production responsibility system for all employees, and to strictly enforce the system of leadership on duty. III. It is necessary to ensure that employees meet the employment requirements and have completed proper training, working with valid certificates in accordance with the law. IV. Major hazard sources must be strictly controlled, change management must be rigorously implemented, and scientific rescue measures must be taken in case of emergencies. V. It is necessary to identify and address potential hazards in accordance with the requirements of the \"Guidelines for the Identification and Rectification of Hazardous Accident Risks in Chemical Hazardous Enterprises\". VI. It is strictly prohibited to operate equipment and facilities in a faulty condition, as well as to shut down the alarm and interlock systems without approval. VII. It is strictly prohibited for alarm systems for leaks of flammable and toxic gases to be in an abnormal state. VIII. It is strictly prohibited to carry out operations such as hot work, work in confined spaces, work at heights, lifting operations, temporary power use, ground excavation, inspection and maintenance, and removal or installation of blind flanges without prior approval. IX. It is strictly prohibited to give illegal instructions or force others to carry out work in a risky manner. X. It is strictly prohibited to carry out work in violation of regulations, to leave one’s post, or to do things unrelated to the job while at work. Ten Regulations for Fireworks and Firecrackers Enterprises to Ensure Production Safety: 1. They must be established in accordance with the law, and must have complete and valid licenses and permits. II. It is necessary to ensure that explosion-proof, fire-proof, lightning-proof, and anti-static facilities are in place. III. It is necessary to ensure that the transfer warehouses, the main drug warehouse, and the main finished product warehouse meet the requirements for production safety. IV. It is necessary to implement a system of leadership on duty and registration for employees entering and leaving the factory. V. It is necessary to ensure that all personnel complete proper training and that those working on hazardous tasks hold the required certifications. VI. Subcontracting, outsourcing, and the unauthorized use of potassium chlorate are strictly prohibited. VII. It is strictly prohibited to exceed the designated scope, number of personnel, dosage limits, or to change the purpose of the workshop without authorization. VIII. Production operations are strictly prohibited in high-temperature and thunderstorm weather. IX. Illegal inspection, maintenance work, and simultaneous construction and production are strictly prohibited. X. It is strictly prohibited to switch posts and for unauthorized personnel to enter the factory area. Ten Rules for Fire and Explosion Prevention in Oil and Gas Tank Farms: 1. It is strictly prohibited to operate oil and gas storage tanks beyond their temperature, pressure, or liquid level limits, as well as to change the storage medium arbitrarily. II. It is strictly prohibited for operators to leave the site when manually removing water, switching tanks, or loading/unloading vehicles in oil and gas tank farms. III. It is strictly prohibited to shut down the safety valves and cut-off valves of operational oil and gas storage tanks, as well as to install blind flanges on the pressure relief and discharge systems. IV. It is strictly prohibited to disable the temperature, pressure, level, as well as combustible and toxic gas alarm and interlock systems in oil and gas tank farms. V. It is strictly prohibited to perform welding work or enter confined spaces in oil and gas tank areas without conducting gas testing and obtaining an operation permit. VI. It is strictly prohibited for the floating disk of an internal floating roof storage tank to touch the bottom during operation. VII. It is strictly prohibited to directly add substances of unknown properties or those that may undergo violent reactions into oil and gas storage tanks or the pipelines connected to them. 8. The use of non-explosion-proof lighting, electrical equipment, tools, and electronic devices in oil and gas tank areas is strictly prohibited. 9. It is strictly prohibited to allow unqualified personnel and contractors without the necessary qualifications to work in oil and gas tank farms; motor vehicles and unauthorized individuals are not permitted to enter such areas without permission. X. It is strictly prohibited to operate equipment and facilities in oil and gas tank farms when they are in poor condition or faulty.

This post was last edited by trant323 on 2018-1-22 at 13:51. It is strictly prohibited for the floating disk of internal floating roof tanks to touch the bottom; care must be taken to maintain a balance between inflow and outflow, and the liquid level must not drop below the minimum level

Agree with the opinion above; the floating platform must not touch the ground while in operation. If testing is required, treat it as a tank under shutdown for maintenance.

In addition to making sure it doesn’t touch the bottom, it’s also necessary to check the amount of nitrogen added to prevent the tank from becoming underpressure

It is strictly prohibited for the floating disk of internal floating roof tanks to touch the bottom; care must be taken to maintain a balance between inflow and outflow, and the liquid level must not drop below the minimum level

Thank you all for your answers. If shutdown measures are taken, what negative consequences could arise from lowering the liquid level, and how can these be prevented? What are the precautions for responding to feed-in?

logologo, 2nd floor? 3 Wealth? **Notice from the General Administration of Work Safety regarding the issuance of the “Ten Provisions for Chemical (Hazardous Chemicals) Enterprises to Ensure Production Safety”, the “Ten Provisions for Fireworks and Firecrackers Enterprises to Ensure Production Safety”, and the “Ten Provisions for Fire and Explosion Prevention in Oil and Gas Storage Areas”. Document No. An Jian Zong Zheng Fa [2017] No. 15. To the work safety supervision bureaus of all provinces, autonomous regions, municipalities directly under the Central Government, and the Xinjiang Production and Construction Corps: The “Ten Provisions for Chemical (Hazardous Chemicals) Enterprises to Ensure Production Safety”, the “Ten Provisions for Fireworks and Firecrackers Enterprises to Ensure Production Safety”, and the “Ten Provisions for Fire and Explosion Prevention in Oil and Gas Storage Areas” are hereby issued to you; please ensure their strict implementation. **State Administration of Work Safety? March 6, 2017? Ten Regulations on Ensuring Production Safety in Chemical (Hazardous Chemicals) Enterprises. 1. Enterprises must be established in accordance with the law, and must possess complete and valid licenses and permits. II. It is necessary to establish and improve a comprehensive safety production responsibility system for all employees, and to strictly enforce the system of leadership on duty. III. It is necessary to ensure that employees meet the employment requirements and have completed proper training, working with valid certificates in accordance with the law. IV. Major hazard sources must be strictly controlled, change management must be rigorously implemented, and scientific rescue measures must be taken in case of emergencies. V. It is necessary to identify and address potential hazards in accordance with the requirements of the \"Guidelines for the Identification and Rectification of Hazardous Accident Risks in Chemical Hazardous Enterprises\". VI. It is strictly prohibited to operate equipment and facilities in a faulty condition, as well as to shut down the alarm and interlock systems without approval. VII. It is strictly prohibited for alarm systems for leaks of flammable and toxic gases to be in an abnormal state. VIII. It is strictly prohibited to carry out operations such as hot work, work in confined spaces, work at heights, lifting operations, temporary power use, ground excavation, inspection and maintenance, and removal or installation of blind flanges without prior approval. IX. It is strictly prohibited to give illegal instructions or force others to carry out work in a risky manner. X. It is strictly prohibited to carry out work in violation of regulations, to leave one’s post, or to do things unrelated to the job while at work. Ten Regulations for Fireworks and Firecrackers Enterprises to Ensure Production Safety: 1. They must be established in accordance with the law, and must have complete and valid licenses and permits. II. It is necessary to ensure that explosion-proof, fire-proof, lightning-proof, and anti-static facilities are in place. III. It is necessary to ensure that the transfer warehouses, the main drug warehouse, and the main finished product warehouse meet the requirements for production safety. IV. It is necessary to implement a system of leadership on duty and registration for employees entering and leaving the factory. V. It is necessary to ensure that all personnel complete proper training and that those working on hazardous tasks hold the required certifications. VI. Subcontracting, outsourcing, and the unauthorized use of potassium chlorate are strictly prohibited. VII. It is strictly prohibited to exceed the designated scope, number of personnel, dosage limits, or to change the purpose of the workshop without authorization. VIII. Production operations are strictly prohibited in high-temperature and thunderstorm weather. IX. Illegal inspection, maintenance work, and simultaneous construction and production are strictly prohibited. X. It is strictly prohibited to switch posts and for unauthorized personnel to enter the factory area. Ten Rules for Fire and Explosion Prevention in Oil and Gas Tank Farms: 1. It is strictly prohibited to operate oil and gas storage tanks beyond their temperature, pressure, or liquid level limits, as well as to change the storage medium arbitrarily. II. It is strictly prohibited for operators to leave the site when manually removing water, switching tanks, or loading/unloading vehicles in oil and gas tank farms. III. It is strictly prohibited to shut down the safety valves and cut-off valves of operational oil and gas storage tanks, as well as to install blind flanges on the pressure relief and discharge systems. IV. It is strictly prohibited to disable the temperature, pressure, level, as well as combustible and toxic gas alarm and interlock systems in oil and gas tank farms. V. It is strictly prohibited to perform welding work or enter confined spaces in oil and gas tank areas without conducting gas testing and obtaining an operation permit. VI. It is strictly prohibited for the floating disk of an internal floating roof storage tank to touch the bottom during operation.

There have been many cases in which air entered below the floating disc, creating a mixed-explosion environment that led to explosions; this must not be done.

In my personal opinion. During shutdown procedures, if it is necessary to lower the liquid level, water can be added first to help displace the oil as much as possible, thereby reducing the amount of flammable gases. Be sure to pay attention to the flow rate during operation to reduce static electricity generation. At the same time, pay attention to the float disc offset and jamming conditions

Order No. 84 of the State Administration of Work Safety strictly prohibits the use of floating trays while in operation. Just carry out tank cleaning procedures (we clean more than a dozen tanks each year, of which around ten are floating roof tanks); the key is to control the flow rate in order to prevent static electricity buildup.