What are the specific regulations for repairing the rubber lining layer?
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We entrust external parties to carry out the gasketing work. All the reports are complete, but leaks were found during the water pressure test. When looking for a manufacturer, the representative from the manufacturer cut off a piece from the leaking area and then repaired it with rubber. I’m wondering now, if repairs are allowed, are there any specific regulations regarding the area or scope of those repairs? Should it still be repaired in whatever way the manufacturer decides, using their own methods? The other party also used the reason of too large an area when conducting an electric spark inspection, saying it was unnecessary. We’re quite speechless. Are there any mandatory regulations to govern the repair process?
I checked hg20677-90. The quality of the rubber lining is classified into four grades; grade 1 is assigned to those that pass all tests. Level 2: The hardness after repair and the results of electrical discharge testing are satisfactory; any remaining defects within acceptable limits correspond to Level 2. Level 3 is achieved when the requirements for user use are met. Level 4: Unqualified level. Therefore, for the quality after repair, unless there are special requirements, the acceptance standards for level 2 and level 3 can be used as a reference. Understanding, right?
The rubber lining can be repaired; we’ll do it. There are no specific regulations; as long as it is repaired properly, but when lining the entire structure with rubber, there are definitely standards to follow.
This post was last edited by jbh121 on 2015-7-28 09:00; do what can be done on the spot. After all, there must be standards and criteria for determining whether something is qualified or not. In this way, users can also be convinced. Therefore, I believe that for the gasket repairs done on-site, the acceptance standard should aim to meet the second one; if necessary, the standard can be lowered to the third one. The reasons are as follows: 1. For on-site repairs, since the technical specifications of the product do not change fundamentally, it should meet the same requirements as those for fully lined products. However, due to various constraints, this is not possible. For example, the product itself requires overall vulcanization and spark inspection. When repairing, it’s definitely impossible to do so in terms of materials, vulcanization, and inspection. Then there is a situation that does not meet the technical requirements of the pattern. 2. During the inspection, if you say it’s been fixed, and he says it isn’t, arguments will arise. Therefore, for the gasket repairs carried out on-site, clear acceptance standards should be established during the work. The basis is the last item of the HG standard, the third-level standard.
There is usually a standard, right? Regarding how to conduct the acceptance
What is being discussed now is the acceptance criteria for rework
Although there are no specific regulations for rework, please follow the initial construction inspection standards; otherwise, how can the quality of use be guaranteed?
There are no specific standards; in short, the repair materials need only meet the requirements of the medium； If you have any questions, feel free to send a private message
Comply with Section 8.6 of HG/T 20677-2013 \"Design Code for Chemical Equipment with Rubber Lining\": 1. If the lining layer has defects such as delamination, bubbles, cracks, or pinholes, repair is permitted; however, the same defect shall not be repaired more than twice. 2. During repair, the defects should be removed until the lining layer is no longer loose. The surrounding area should be processed into a 30° groove; the double-layer lining should be made in a stepped shape. The area where removal takes place and within 50 mm to 100 mm around it must be cleaned thoroughly, so that the underlying metal surface is visible. Then, depending on the structure of the equipment and piping as well as the operating conditions, repair should be carried out using one of the following methods: (1) Use the original rubber material for repair, followed by partial or full vulcanization, but the layer of original rubber must not be over-vulcanized. (2) Repair using fiberglass reinforced plastic and mortar.