Should an emergency accident pond be covered? CNPC and Sinopec have different regulatory requirements

Thread Content

Currently, some regulations related to emergency accident ponds, such as the \"Technical Guidelines for Environmental Risk Assessment of Construction Projects\" (HJ169-2018) and the \"Design Specifications for Environmental Protection in Chemical Engineering Construction Projects\" (GB/T 50483-2019), do not explicitly require that accident emergency ponds must be covered. SH/T 3224-2024 \"Code for Monitoring of Rainwater in the Petrochemical Industry and Design of Facilities for Storing Accident Drainage\" – The storage tanks for accident drainage should be of open type, and facilities such as inspection passages, fences, and ladders should be provided ； Q/SY 08190-2019 Standard for the Prevention and Control of Water Body Pollution in Accident Conditions stipulates that intermediate accident buffer tanks and terminal accident buffer tanks should be enclosed. The provisions of SH/T 3224-2024 and Q/SY 08190-2019 are also inconsistent; the former is a recommended industry standard that does not have mandatory force unless mandated by mandatory standards or laws, while the latter is a corporate standard of CNPC and is applicable within CNPC’s own organizations. The current mainstream technology involves an underground design, which allows accident wastewater to flow away by gravity, and measures such as impermeability protection and corrosion prevention should be taken. Sealing has its advantages and disadvantages; when making a decision, it is necessary to consider both the nature of the substances stored by the company and its safety management capabilities. The advantage of having a cover is that it prevents rainwater from entering, reduces the escape of volatile substances, unpleasant odors, or harmful gases. It also enhances safety by preventing people and animals from falling accidentally. Covering it also carries risks; the main risk is the creation of a confined space. If ventilation is poor after covering, toxic and harmful gases can easily accumulate, posing safety hazards. Additionally, covering it incurs additional costs. The main advantage of not having a cover is that it is inherently safer, as good ventilation prevents the accumulation of flammable and toxic gases, avoiding the formation of deadly confined spaces. It also has lower construction costs, is simple to maintain, and facilitates inspection, cleaning, and emergency use. The main risk of not using a cover is the risk of environmental exposure, such as excessive rainfall causing the tank to overflow due to overload, the release of volatile substances, and poor safety isolation. Therefore, the decision regarding whether to cover the emergency accident pool requires an assessment of the properties of the substances stored there as well as a comprehensive evaluation of the company’s safety management capabilities. Priority should be given to the provisions outlined in the environmental impact assessment documents and their approvals; if such documents contain explicit requirements, they should serve as the primary basis for decision-making. If the environmental impact assessment does not provide specific guidelines, a judgment can be made based on the characteristics of the substances stored and the company’s safety management capabilities. If the stored substances are mainly fire-fighting wastewater or oily wastewater, which do not tend to produce highly toxic or flammable gases, the risk associated with covering them is relatively controllable. If the stored materials or wastewater may generate toxic and harmful gases, and if a company does not have the capability to maintain high standards of safety control over the long term, then opting for an open or semi-open design without covers is a more practical and inherently safer choice from the perspective of preventing serious safety accidents. If sealing is necessary, strict management in accordance with the requirements for confined spaces must be followed