Reviewing the Old to Discover the New (Series 24)

I. Specifications for blind flanges 1. When selecting the specifications for a blind flange, factors such as the pressure in the pipeline, the outer diameter of the blind flange, the allowable stress of the material used, and the thickness of the material must be taken into consideration. It is strictly prohibited to use blind flanges that do not meet the actual requirements on site. 2. If the conditions for using an \"8\"-shaped blind plate are met, an \"8\"-shaped blind plate should be used. 3. Blind plates should be used in areas where it is feasible to do so. 4. For those that do not meet the conditions of Articles 4 and 5, it is possible to consider manufacturing blind plates oneself. Self-made blind plates shall be manufactured only after being verified by the equipment management personnel to meet the requirements of Article 3. II. Specifications for blind plate materials 1. In principle, the same material as that of the corresponding flange should be used; for self-made blind plates, the material requirements of the substance to be contained must be taken into account. III. Requirements for installing blind flanges 1. When installing a blind flange, gaskets should be used on both sides, and the gaskets must match the blind flange and the flange itself. It is strictly prohibited to use blind flanges or gaskets without gaskets or with gaskets on only one side. It is also forbidden to use blind flanges and gaskets whose diameter and pressure rating are lower than those required by the flange. For flanges with special requirements (such as enamel-coated flanges), gaskets and blind plates that meet the specified standards should be selected. 2. The bolts shall meet the requirements of the corresponding flanges and shall be fully tightened. 3. Install blind flanges in the pipelines, at the nearest shut-off valve to the pipeline or equipment that is to be emptied, ensuring that the material intended to be isolated by the blind flange does not leak out directly. IV. Blind Flange Management 1. Blind flange management follows a \"triple integration\" approach that includes blind flange diagrams, tables, and flags. The blind flange diagram indicates the specific location, number, and specifications of each blind flange; the table lists the numbers and specifications of the blind flanges; while the flag shows the number of the blind flange. The numbers and specifications in all three are consistent with each other. 2. The preparation of the blind flange diagrams and tables is the responsibility of the process technicians, while the filling out, hanging, and removal of the blind flange tags are the responsibility of the actual operators. The blind flange diagrams, tables, and tags should be assigned uniform numbers for easy identification. 3. The installation and removal of blind plates are subject to a two-level responsibility system involving the operators and the inspectors/reviewers, with the reviewers having to be team leaders, section chiefs, process engineers, or unit managers.

When removing the flange, prevent residual pressure from causing accidents. The material and thickness of the blind plate must meet the technical requirements.

1. The management of blind plates follows a \"trinity\" approach that includes blind plate diagrams, blind plate tables, and blind plate flags. The blind plate diagram indicates the specific location, number, and specifications of each blind plate; the blind plate table lists the numbers and specifications of the blind plates; while the blind plate flag shows the number of the blind plate. The numbers and specifications in all three are consistent with one another. 2. The preparation of the blind flange diagrams and tables is the responsibility of the process technicians, while the filling out, hanging, and removal of the blind flange tags are the responsibility of the actual operators. The blind flange diagrams, tables, and tags should be assigned uniform numbers for easy identification. 3. The installation and removal of blind plates are subject to a two-level responsibility system involving the operators and the inspectors/reviewers, with the reviewers having to be team leaders, section chiefs, process engineers, or unit managers.

Blind plates used for startup/shutdown maintenance and those used in daily production are managed through separate registration (see the attached table for the record format). It is required to assign a specific person to be responsible for the management of blind plates, with other managers providing cooperation and conducting regular inspections and organization. 1. The production workshop shall prepare the blind flanges actually required by the unit, assign them uniform numbers, and hang the flange tags in the locations specified in the blind flange diagrams and lists. Before carrying out the removal and installation of blind flanges, the equipment on which the blind flange is located must first have the medium inside the associated devices or pipelines treated. For the installation or removal of blind flanges between upstream and downstream devices that are difficult to isolate, or blind flanges related to the system, the relevant unit must first submit an application, after which the Production Technology Department takes charge of coordinating the relevant units to carry out the task. During startup and shutdown operations, when removing or installing blind flanges, the workshop in question is required to make advance plans for such tasks and submit them to the construction party. It is necessary to arrange the timing of these operations properly, ensure that the site conditions are suitable before removing or installing the blind flanges, and obtain the necessary permits before carrying out these tasks. 4 Maintenance workers must be conscientious and responsible; they need to verify the blind plate numbers and the material of the gaskets to ensure accuracy, wear appropriate personal protective equipment, carry out their tasks in strict accordance with the maintenance procedures, and complete them within the time frame specified on the work order. 5 Before maintenance personnel go to the site to remove (install) blind flanges, they must establish contact with the workshop in question. Personnel from the production unit must carefully inspect the pipelines connected to the area where the blind flanges will be used, close the relevant valves to eliminate any residual residues or gases in that area, and confirm that there is no pressure present. Only after signing off on the work order can the operation of removing (installing) blind flanges proceed. 6. The personnel from the maintenance unit must carry out blind plate removal (installation) tasks under the supervision of the person in charge of blind plates (or) the operator at the production unit; in workshops where blind plates pose a risk to production safety, a supervising manager must be present at the work site to provide safety oversight and guidance. If any abnormalities are detected during the operation, the on-duty personnel or relevant staff should be contacted promptly to handle them. 7 After the work is completed, the person in charge of the blind flanges at the maintenance unit signs to confirm, after which the work order is returned to the issuing unit for archiving. The supervisor on the production unit removes (or attaches) the blind flange identification tag at the location where the blind flange was installed or removed, signs on the blind flange work order, submits it to the workshop’s chief technician for confirmation, and carries out the necessary record-keeping.

The management of blind flanges follows a \"trinity\" approach that includes blind flange diagrams, tables, and flags. The blind flange diagram indicates the specific location, number, and specifications of each blind flange; the table lists the numbers and specifications of the blind flanges; while the flag bears the number of the blind flange. The numbers and specifications in all three are consistent with one another. When selecting the specification of a blind flange, factors such as the pipeline pressure, the outer diameter of the blind flange, the allowable stress of the selected material, and the thickness of the material must be taken into account. It is strictly prohibited to use blind flanges that do not meet the actual requirements on site. If the conditions for using an 8-shaped blind flange are met, an 8-shaped blind flange should be used. Article 5: Blind plates shall be used in locations where conditions permit their use. For those that do not meet the conditions of Articles 4 and 5, considering the use of self-made blind plates is possible. Self-made blind plates shall be manufactured only after being verified by the equipment management personnel to meet the requirements of Article 3. Material specification for blind flanges: In principle, the same material as that of the corresponding flange should be used; for self-made blind flanges, the material requirements of the substance to be contained must be taken into consideration

1. Work procedures and requirements: During major maintenance, for the installation and removal of blind flanges, it is required to assign a specific person to be responsible for managing these blind flanges, with other managers providing support and carrying out regular inspections and organization. 2. Registration management for installation (removal) of blind plates: Each workshop shall prepare a detailed list for confirming the installation (removal) of blind plates in accordance with the requirements of the branch factory. This list should include information such as the blind plate’s number, specifications, purpose, date of installation (removal), and the person who conducted the confirmation (for specific formats, refer to the attachment). The installation (removal) of each blind flange must be inspected and confirmed by a designated person. During periods of shutdown or restart, at 16:00 every day, the workshop’s blind flange supervisor fills out a detailed record of the blind flange installations and removals, takes it to the control room to have it verified, and reports the progress to the branch factory’s blind flange supervisor. Punctuality is required, along with accurate filling out and reporting, as well as neat and clear handwriting. 3. Blind plate information card: The blind plate information card includes the blind plate number, person in charge, pipe diameter, thickness of the blind plate, name of the pipeline, status of the blind plate, and planned date (for specific format, refer to the attachment). The blind flange information card must be hung at the location corresponding to the blind flange one week before the maintenance work begins. 4. Blind plate identification tag: The content of the blind plate identification tag includes the blind plate number and the person in charge (for the specific format, refer to the attachment). Immediately after the blind plate installation is completed, a tag corresponding to each blind plate is attached based on its number and location; the information card related to that blind plate is then removed. When the blind plates are taken off once the maintenance is finished, the corresponding tags are also collected and submitted to the control room. 5. Blind plate inspection and confirmation: After installing (removing) the blind plate, the relevant person in charge of the workshop organizes a second confirmation. The person in charge of the blind flanges in the control room conducted another inspection to confirm. 6. Inspection and Assessment

One work order per blind flange, along with a register for blind flanges