Update for TEMA 2019
Update for TEMA 2019
TEMA has updated the version 2019 (Tenth Edition) in 2019. It has been 12 years since the 2007 edition to 2019. Many friends are curious about what the changes are?
This article will introduce the new update content of TEMA to you. Please point out the omissions.
The main updates of the 2019 edition are as follows:
- Numerical analysis of adding expansion joint (one dimensional FEA);
- Design rules of horizontal saddle;
- Dimension data of flange;
- Guide and configuration of shell side inlet distribution section;
- Research on the design of reducing scaling;
- Guide for expansion of tubesheet joints;
- Sketch of shoulder bolt for removable tube bundle;
- Combined with ASME PCC-1 recommended bolt connection.
- Update international material list;
- Update metric bolt data sheet;
- Update graphics and charts with modern and standardized format appearance.
Its updated content is introduced on the official website: http://www.tema.org/highlight10.asp
The following is an analysis of the specific changes in each chapter.
TEMA’s numbering rules have been improved in 2019.
2007 Edition No.: RCB1.421
Version 2019 No.: RCB22.214.171.124
It’s easy to think of the 2007 edition as the 421 article of the first article.
The level of the 2019 version is clearer. This provision indicates that there are four branches of the tree, which is in line with the international general modern standardized numbering rules.
G-2.1 Inspection requirements
2007: The manufacturer shall carry out the inspections required by the ASME Code.
2019: The manufacturer shall carry out the inspections required by the Code.
Interpretation: ASME is deleted from the new version of inspection requirements. The reason may be that the tolerance provisions in ASME are not as detailed as those in tema. TEMA is mainly a structural code for heat exchanger, and the structural dimension requirements are more stringent than those of ASME.
G-3.1 Name plate
2007：Name plates for exchangers manufactured in accordance with Classes “R” and “B” shall be austenitic (300 series) stainless. When isulation thickness is specified by the purchaser, the name plate shall be attached to the bracket weled to the exchanger.
2019：The nameplate may be attached via a bracket welded to the exchanger, and shall be visible outside any insulation.
Interpretation: the requirements of 300 series stainless steel for TEMA “R” and “B” nameplates are deleted in the new edition.
The name plate needs to be installed on the name plate bracket welded on the heat exchanger. When there is heat preservation, it should extend out of the outer surface of the heat preservation.
When there is thermal insulation, the name plate needs to be installed on the name plate bracket. What if there is no insulation?
The provisions of the 2019 edition are more specific. No matter whether there is thermal insulation or not, the name plate should generally be installed on the name plate frame (avoid direct welding on the equipment).
G-4.1 Drawings for approval and change
Interpretation: the problem of responsibility division is described more clearly. It specifies the minimum information to be included in the drawing, the drawing format (PDF) submitted by the manufacturer, and how to deal with the modification. If the cost increases due to the modification, the manufacturer is responsible for informing the cost of the modification.
G-4.2 Drawing for record
2007: Manufacturer submits 3 paper copies.
2019: PDF electronic version submitted by manufacturer.
Interpretation: the submission of PDF electronic version is more convenient. If the paper version is required, it can be separately agreed in the contract.
Disclaimer, total liability and protection
Interpretation: add g-5.6, 5.7, 5.8, disclaimer, total liability and guarantee.
The overall purpose is to protect the heat exchanger manufacturer. Clarify the responsibilities of both parties, exemption clauses, etc., and only be responsible for the written conditions proposed by the buyer, such as whether the heat exchanger is suitable for a specific purpose.
E126.96.36.199 and e188.8.131.52 are added to meet the requirements of tightening bolts.
E3.2.5 is added, combined with ASME pcc-1, the operation steps of tightening bolts are recommended.
Interpretation: combined with the bolt connection recommended by ASME PCC-1.
Add E-5 and change the configuration of heat exchanger.
Interpretation: if it is necessary to change the configuration of the heat exchanger, such as upgrading the material, increasing the design pressure or temperature, or changing the gasket type. Whenever the components of the heat exchanger are changed, the influence on the overall design must be considered. After the change, it also needs to meet the requirements of the specification and TEMA.
This article is applicable to the design and transformation, and reminds that the transformation should also conform to the specifications.
For example, to modify the gasket, we should pay attention to whether the flange thickness is OK, whether the pressure and temperature are modified, whether the original strength and flange grade are met, etc.
RCB-1.3.1 hydraulic test
When the tube side pressure is higher than the shell side pressure, the tube bundle should be tested outside the shell side.
The purpose of this method is to subject the tubesheet joint to more rigorous and visible tests on both sides.
The shell side test pressure is high. If leakage occurs during the test, which heat exchange tube has problems can be detected directly from the tube sheet joint, and remedial measures can be taken.
However, when the tube side test pressure is high, the inside of the fixed tube sheet is not visible. If the tube sheet joint leaks during the hydrostatic test, it is impossible to determine which heat exchange tube has the problem. Therefore, the specification hopes that the tube bundle can directly observe the leaking heat exchange tube during the pressure test outside the shell side.
But for fixed tubesheet heat exchanger, because of the structure problem, it is impossible to test the pressure of tube bundle separately.
Although the specification has been deleted, its principle of “strict and visible” is right.
In China, this principle is generally implemented in two ways:
If the pipe pressure is not high enough, the shell side pressure test = pipe side pressure test can be increased without affecting the cost.
The other is that the tube side pressure is much higher than the shell side, so the shell side leakage test (ammonia leak detection, helium leak detection) is used to determine which heat exchange tube has the problem.
Add RCB-184.108.40.206 MDMT:
Interpretation: the minimum design metal temperature MDMT is generally specified by the buyer. It is necessary to consider the operating temperature, minimum ambient temperature and abnormal conditions such as self cooling (for example, some equipment discharge compressed gas, resulting in sudden drop of outlet temperature). MDMT is used to evaluate whether impact test is needed.
RCB-220.127.116.11 internal floating head covers
2007: Corrosion allowance on the outside of the flanged portion may be included in the recommended minimum edge distance.
2019: Corrosion allowance need not be added to the recommended minimum edge distance in table D-5 or D-5M. P 38.
Interpretation: the dimensions in figures D-5 and d-5m do not consider the effect of corrosion allowance. The meaning is similar, the expression is more clear.
RCB-2.2.2 marking of integral finned tube
Interpretation: for integral finned tube, the thickness of fin and bare tube should be marked at the same time.
Modification of RCB-2.3.1 U-bend requirement formula:
Interpretation: for carbon steel, the formula remains the same.
For duplex steel, super stainless steel, titanium, high nickel alloy steel, and other cold work hardened tubes, the C value of 2 will increase the required pre bend thickness.
For R < 2d0, when the material is very easy to work hardening or the thickness of straight pipe is less than d0 / 12, the flattening ratio can exceed 10%. At this point, special considerations based on experience may be needed. How to think about it
Api660, the requirement for flattening ratio is that no more than 10% is allowed.
9.7.4 Flattening tolerances after bending of U-tubes shall not exceed 10 % of the tube outside diameter。
TEMA gave its restrictions to the manufacturer.
RCB-4.3 Transverse baffle
CB-18.104.22.168 Longitudinal baffle
Interpretation: the thickness of longitudinal diaphragm is divided into carbon steel and stainless steel, the thickness of carbon steel remains unchanged at 6.4, and the thickness of alloy steel can be taken as 3.2.
CB-22.214.171.124 weld leg height of longitudinal diaphragm
Interpretation: the content remains unchanged, crack the chain reference.
In the 2007 edition, C refers to B, B refers to A.
In the 2019 edition, C directly refers to A.
RCB-4.4.3 vibration solutions for special working conditions
New in 2019:
Interpretation: for RCB-4.4.3, 1-4, how to consider the vibration of baffle, support plate and tube bundle, TEMA gives four suggestions:
- 1. Reduce the baffle spacing within the allowable pressure drop range.
- 2. On the baffles, additional tube banks are provided in the inlet and outlet spaces.
- 3. Provide additional support plates between the baffles, and the support will not hinder the fluid flow in the tube bundle.
- 4. Modify the baffle type (for example, tube bundle vibration, change to ntiw without tube arrangement in window).
RCB-4.5 baffle support spacing description
What’s new in 2019:
Interpretation: Section 4.5 is about general baffles, maximum and minimum spacing of supporting plates, and unsupported span. The actual baffle spacing should be determined by heat transfer or hydraulic calculation, and the operating conditions and heat load should be considered to eliminate fluid induced vibration.
RCB-4.6.1 Setting of anti impact baffle
Interpretation: in the 2019 edition, the unit description of speed and density is put in the front to avoid the following use of speed and density.
- The detailed description of single phase fluid is supplemented;
- Other gases and vapors are added, which contain steam.
When the speed is too fast, another solution is given to increase the entrance distribution section.
Interpretation: the baffle can be replaced by an anti impact bar or an inlet distribution section.
RCB-4.6.3 pipe side anti scour
Interpretation: when the two-phase fluid + axial inlet nozzle + ρ V2 value is added to the tube side anti scour structure, it needs to be set.
Compared with GB151, it means liquid ρ V2 value + axial inlet nozzle.
RCB-4.8 bypass seal
Interpretation: new bypass baffle, baffle and other anti short circuit structure requirements. Compared with the original simple reference, the regulations of the 2019 edition are much more detailed.
It can be compared with API 660.
RCB-4.9 Kettle reboiler
Interpretation: increase the requirements for slide way and limit plate of U-tube bundle of kettle reboiler.
In addition to the angle steel limit in 2007, the limit structure as shown in the figure above is added.
Delete R-6.33, CB-6.33
Interpretation: the flatness of CB-6.33 in 2007 is wrong in RCB-1.3, which is the content of hydrostatic test.
In 2019, R-6.33 and CB-6.33 are deleted for the flatness requirement of the sealing surface contacting the gasket at the split diaphragm. Because this is a manufacturing tolerance requirement, the 2019 version is moved to chapter F-5:
Compared with the requirements of 2007, the requirements equivalent to CB are the same as those of R.
RCB-6.4 minimum width of split diaphragm groove
Interpretation: modification of the expression of minimum width of split diaphragm groove.
For the nominal diameter of ＜=23 “, the nominal diameter of ＜ 24” in 2019 is slightly different.
Interpretation: add description: the size beyond the scope of the table, allowing interpolation and extrapolation.
There are two ways, one is interpolation, the other is strict, when not clear, generally choose strict. Now the specification allows interpolation.
RCB-7.2.4 Modification of tube sheet hole slotting in hydraulic expansion
Interpretation: the requirements of tube sheet hole groove for hydraulic or explosive tube expansion are modified. The requirement of two grooves larger than 76mm is deleted.
Generally, the tube sheet pull-out test should be done to confirm the expansion joint structure.
RCB-7.3.1 Expansion joint of tube sheet
Interpretation: the 2019 edition gives the thinning rate of tubes made of different materials after tube expansion. Because when the tube is expanded, the tube expands tightly against the tube sheet hole, forming a stress seal between the tube and tube sheet. When the pipe is expanded, the pipe wall will be thinner. Only a certain thinning rate can make the seal more reliable. Through the target thinning rate, the target inner diameter of the expanded pipe can be calculated.
Therefore, it is necessary to measure the first few pipes and the hole diameter to confirm that the pipe wall is thinned to the target value, and the torque when the thinning is achieved is the target torque, which is used for the actual pipe expansion.
The specification wants to ensure the sealing effect by making the pipe achieve the target thinning rate.
RCB-9.1.3 Split diaphragm
Interpretation: add step machine for split partition in 2019.
New RCB-10.2.2 Installation nozzle
Interpretation: added when to consider the use of uw-16.1 nozzle. Generally, if the shell wall thickness is too thick or the nozzle diameter is too small, the installation type nozzle can be selected.
When the placement nozzle is used, NDT should be added to the hole opening of the cylinder before and after welding to avoid the influence of the cylinder stratification.
Delete RCB-10.7 in 2007
Interpretation: large diameter flange and ordinary flange, need to meet the requirements of ASME.
RCB-11.7 increases the value of BR
Interpretation: for the effective width of gasket, according to ASME VIII I mandatory Appendix 2, half of the actual width should be taken.
RCB-11.8 new requirements and schematic diagram of shoulder bolt
Interpretation: shoulder bolts are generally used in extractable tube bundles. The number of TEMA is similar to API 660, which is 25%, at least 4.
Update expansion joint calculation
Interpretation: the two-dimensional axisymmetric model is adopted in 2007, and the two-dimensional axisymmetric model or one-dimensional line element model can be used in 2019.
One dimensional line element has not been used in the calculation of expansion joint before. Generally, two-dimensional axisymmetry is used more.
If you have experience or case, please contact me for discussion.
Table D-3 increase flange size
Interpretation: it is not clear why a table should be made for the flange, and all flange dimensions refer to ASME B 16.5.
No more than 24 inches, low practicability.
RGP-G-7.1.1 add asymmetric saddle calculation
Interpretation: SW6 already has asymmetric saddle calculation, pvelite also has, so it has no influence on the current design.
New entrance distribution section
Interpretation: add some requirements of entrance distribution section. For the inlet velocity is too large, improve the distribution effect, reduce the fluid induced vibration are good.
Calculation of WRC537 when nozzle load increases.
Interpretation: wrc537 adopts the fitting formula, and the calculation range is larger than wrc107, which can generally meet the engineering needs.
What to do if the calculation of local stress exceeds the limit
RGP-RCB-11.5 Remove large diameter flange
Interpretation: delete some special instructions for large diameter low pressure flange, flange shall be in accordance with ASME and WRC 538.
New design method of fouling mitigation
Interpretation: in the design, pay attention to the flow rate (shear stress) and wall temperature can prevent obvious scaling. Small design margin (generally < = 30%) can be added to the design to solve the design uncertainty,.
For example, for cooling water, the design and operation of control water temperature should not exceed the maximum fluid temperature of 49 degrees and the maximum wall temperature of 60 degrees. Keeping the flow rate in the heat exchange tube above 1 m / s can slow down the scaling.
Generally determined by the process, many engineering regulations for the flow rate is greater than 1.5m/s.
Interpretation: the value method of equivalent pressure is added when U-tube sheet is not welded with tube side and shell side, but also used as flange.
U-shaped tubesheet is also used as flange, as shown in the figure below:
The equivalent pressure needs to consider the equivalent pressure of the bolt load, which is quite difficult to understand. Because the bolt load is not generally considered to be transferred to the tubesheet.
The only explanation is that this is a conservative algorithm, considering that the flange of the tube plate will be transferred by bolt load during hydrostatic test.
In addition, because the calculation method of TEMA tube plate is relatively rough, it is generally calculated according to uhx. Even if it is modified, it may not be used by others.
TEMA 2019 has not been changed much, and it does not extend the diameter and scope of use of the equipment. For most of the structure, size and tolerance, no changes have been made.
The 2007 error was updated and the expression was more accurate, and the detailed structure of shoulder bolt and bypass baffle was added. It provides more basis for detailed structural design.
The calculation part is modified less, and further research is needed for expansion joints.
Source: China Flange Manufacturer – Yaang Pipe Industry (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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