Section 8 — Heat Transfer Equipment

Tube Material and Selection

IPE Engineering Practice IPE-EP-8-1-9

Document number: IPE-EP-8-1-9 · Section: 8 — Heat Transfer Equipment

SCOPE

This Practice governs requirements for heat exchanger tube design, material and selection.
Any deviation from this Practice, or Practices referenced herein, must be approved by the procedure described in EP 1–1–3.
An asterisk (*) indicates that a design by the Owner or Owner’s Engineer is required, or that additional information is furnished by the Purchaser.
A revision bar indicates all changes made to this Revision.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

IPE Engineering Practices
EP 1–1–3 Deviations to IPE Engineering Practices EP 8–1–1 DS TEMA Shell and Tube Heat Exchangers Data Sheet EP 8–1–4 DS Air Cooled Heat Exchangers Data Sheet EP 8–1–5 DS Double Pipe Heat Exchangers Data Sheet
ASME Codes
Sec VIII Pressure Vessels, Division 1
TEMA
Standards of Tubular Exchanger Manufacturers Association

DEFINITIONS

Inspector – A Inflection Point Engineering, LLC appointed engineer or inspector.
Owner – Inflection Point Engineering, LLC .
Owner’s Engineer – A Inflection Point Engineering, LLC appointed engineer.

TUBE MATERIAL SELECTION

(*) The tube material shall be as specified on the Data Sheet of the applicable heat exchanger Refining Practice as shown in Table 1.
(*) Tubes shall be in accordance with SA214, SA179, SA249 or SA213, unless otherwise specified on the Data Sheet. Seamless tubing is required for all HF acid services and for those services with design pressures of 1000 psig or higher.
(*) For lethal services using carbon steel tubes, the tubes are to be seamless. For lethal services using other than carbon steel, due consideration is to be given to the cost effectiveness of using seamless tubes versus welded tubes plus the required NDE inspection. The Owner’s Engineer must approve the use of welded tubes in lethal service.
Austenitic stainless steels shall be the low carbon types 304L or 316L or stabilized types 321 or

347. This limitation does not apply to solution annealed, resistance welded exchanger tubes for floating head bundles that are rolled, but not welded to the tubesheet.

Regular carbon grades of 304 and 316 stainless steel are not permitted in U–bends since heat treating of the U–bends is required. Types 304L and 316L shall be used.
When inhibited admiralty tubes are used, all other parts in contact with the tube side fluid shall be inhibited admiralty or a brass alloy resistant to dezincification.

TUBE DESIGN

(*) The design temperature for tubes under external pressure may be determined by TEMA, Paragraph RCB–1.42. Calculations shall be submitted to the Owner’s Engineer for approval.
Tubes shall be 5/8 inch minimum outside diameter for non–process services. Tubes shall be 3/4 inch minimum outside diameter for general process services. When the tubeside fouling factor is 0.003 or higher, tubes shall be 1 inch minimum outside diameter.
For sulfur condensers, tubes shall have an outside diameter of 1–1/2 inches minimum, with a tube wall thickness not less than 0.134 inch.
(*) Unless approved by the Owner’s Engineer, tubes shall be ordered to nominal, minimum or average wall, but the tube thickness shall not be less than shown in Table 2.
(*) The use of externally surface enhanced tubes shall not be permitted, unless approved by the Owner’s Engineer.
All U–bends shall be formed from a single length having no circumferential welds.
The minimum bend diameter (inner diameter) of U–bends shall be greater than or equal to 3 times the outside diameter.
Minimum tube thickness and out of roundness tolerances shall be in accordance with TEMA R Standards.

HEAT TREATMENT

All U–bends shall be heat treated after bending. The heat treatment shall extend at least one foot beyond the U–bend tangent line.
Heat treatment of carbon steel shall be in accordance with Section VIII, Division 1 of the ASME Code.
(*) The heat treating temperature for type 300 stainless steels shall be 1650 ± 25F. For types 304L and 316L, this temperature shall be held for at least one hour. For types 321 and 347, this temperature shall be held for at least two hours. After the hold period, the tubes shall be allowed to air cool. These requirements shall be subject to the approval of the Owner’s Engineer.

(*) For other materials or alternate methods of stress relieving, the Manufacturer’s proposed procedures shall be submitted in writing for approval by the Owner’s Engineer.

7.0 TABLES

TABLE 1

REQUIRED DATA SHEETS

Heat Exchanger Type	IPE Engineering Practice
Shell and Tube (including non–process services and bundle replacement)	EP 8–1–1 DS
Air Coolers	EP 8–1–4 DS
Multi–tube	EP 8–1–5 DS

TABLE 2

MINIMUM REQUIRED TUBE THICKNESSES (1) (2) (3)

Material	Tube Outside Diameter	Tube Outside Diameter	Tube Outside Diameter
	3/4 inch	1 inch	1–1/4 inch
Carbon Steel and Low	0.095	0.109	0.109
Chrome (9% Chrome or
less)(4)
Copper and Copper Alloys (4)	0.065	0.083	0.109
Austenitic and Duplex Stainless Steels (5)	0.065	0.065	0.083
Titanium (4)	0.049	0.049	—

Notes

All dimensions are in inches.
0.049 inch is thinnest wall acceptable for any material.
(*) Other materials and tube diameters shall be as specified on the Data Sheet.
Minimum wall thicknesses are shown.
Average wall thicknesses are shown.

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