What standard heat exchange tubes are used for the Grade 1 tubes in the new 151 tube bundle?
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The precision of the new Type 151 tube bundles must meet the requirements of NBT47009; as a result, the 9948 standard cannot be used for these tubes. So, should the standard specification sheet for the heat exchange tubes indicate NBT47009 or 9948? 47009 isn’t the standard for pipes, right?
Using 9948 tubes, the primary tube bundle must meet the ordering specifications of 47019
The pipe standard definitely specifies 9948; for Class I tube bundles, it is also required that the requirements of NB/T47019 be met at the time of procurement.
In this case, 9948 becomes virtually meaningless; either the standards need to be updated, so that what is available for 9948 is also available for 47009
9948 is a standard for pipe materials; it is a **mandatory standard that must be followed. The NB standard is a standard set by the Ministry of Energy, and it is a recommended standard. This standard is rarely taken into consideration during the design phase, unless some client organizations request it and insist on purchasing materials in accordance with this standard. So these two standards are not contradictory
9948 is far from meeting the requirements of 47009; therefore, using the 9948 standard for the tubes in the primary tube bundle seems quite unreasonable
It is the minimum requirement for standard time; you can increase additional requirements on top of these minimums, which essentially constitutes customization. This is how we often make requests.
Each standard specifies different grade requirements; when placing an order, it is not sufficient to provide only the standard number – it is also necessary to indicate which grade within that standard should be applied. For example, the allowable tolerance for outer diameter should correspond to the advanced grade requirements specified in NB/T47019.1. Some standards set extremely broad acceptable ranges; they are drafted by the manufacturers themselves, which is to the advantage of those manufacturers. Therefore, as a buyer, it is essential to carefully examine the terms in the standards – otherwise, you will be the one to suffer losses·················