ASME PTC 19.3 TW-2010 pdf download

ASME PTC 19.3 TW-2010 pdf download.Thermowells.
Proposing Revisions. Revisions are made periodically to the Code to incorporate changes that appear necessary or desirable, as demonstrated by the experience gained from the application of the Code. Approved revisions will be published periodically. The Committee welcomes proposals for revisions to this Code. Such proposals should be as specific as possible, citing the paragraph number(s), the proposed wording, and a detailed description of the reasons for the proposal, including any pertinent documentation. Proposing a Case. Cases may be issued for the purpose of providing alternative rules when justified, to permit early implementation of an approved revision when the need is urgent, or to provide rules not covered by existing provisions. Cases are effective immediately upon ASME approval and shall be posted on the ASME Committee Web page. Request for cases shall provide a Statement of Need and background information. The request should identify the Code, paragraph, figure or table number(s), and be written as a Question and Reply in the same format as exist- ing Cases. Requests for Cases should also indicate the applicable edition of the Code to which the proposed Case applies. Interpretations. Upon request, the PTC Standards Committee will render an interpretation of any requirement of the Code. Interpretations can be rendered only in response to a written request sent to the Secretary of the PTC Standards Committee. The request for interpretation should be clear and unambiguous. It is further recommended that the inquirer sub- mit his request in the following format: Subject: Cite the applicable paragraph number(s) and a concise description. Edition: Cite the applicable edition of the Code for which the interpretation is being requested. Question: Phrase the question as a request for an interpretation of a specific requirement suitable for general understanding and use, not as a request for an approval of a proprietary design or situation. 4-1 CONFIGURATIONS Figure 4-1-1 shows a schematic diagram of a ther- mowell, along with its characteristic dimensions. Typical thermowell attachment confgurations include threaded, socket weld, weld-in, lap-joint (Van Stone), and integral-fanged as shown in Figs. 4-1-2, 4-1-3, and 4-1-4 (see also Table 4-1-1). These fgures are representa- tive of common practice but do not display all allowable attachment confgurations. The selection of a specifc attachment method is subject to the governing piping or pressure vessel code. Use of ball joints, spherical unions, or packing gland installations are not permissible in Performance Test Code applications. The dashed line in Fig. 4-1-1 indicates the support plane, which is an imaginary extension of the supporting-struc- ture surface that passes through the shank of the ther- mowell. The unsupported length, L, is calculated as the distance from the tip of the thermowell to the intersection of the thermowell axis with this surface. For thermowells mounted on fanges or welded into weld adaptors, the support plane will be a fat plane. However, for thermo- wells mounted by direct welding into a pipe wall, the sup- port plane will actually be a curved surface with the same curvature as the inner pipe wall. For this case, the support plane should be approximated as a plane located at a dis- tance from the thermowell tip equal to the largest actual distance from the tip to any point on the true curved sup- port surface. For thermowells welded to a fange or pipe wall at an angle, the support plane will not be normal to the thermowell axis. For nonstandard attachments, this Standard covers the design requirements of the thermowell only. The designer shall account for the support compliance of the attachment (refer to subsection 6-6), and the attachment method shall meet all the requirements of the governing piping or pressure vessel code.