ASME SEC VIII D1 MA APP 23

01

APPENDIX23

EXTERNAL PRESSURE DESIGN OF COPPER,

COPPER ALLOY,AND TITANIUM ALLOY CONDENSER AND HEAT EXCHANGER TUBES WITH

INTEGRAL FINS

23-1SCOPE

The rules in this Appendix cover the proof test

procedure and criteria for determining the maximum

allowable external working pressure of copper,copper

alloy,and titanium alloy condenser and heat exchanger

tubes with helical?ns that are integrally extended from

the tube wall as an alternative to the requirements of

UG-8(b)(4).This Appendix may only be used when

the speci?ed corrosion allowance for the tubes is zero.

In addition,when using SB-543,this Appendix may

only be used when the?nning operations are performed

after the tubes have been welded,tested,and inspected

according to SB-543.

23-2MATERIALS

(a)Copper and copper alloy tubes shall meet SB-

359or SB-543.

(b)Titanium alloy tubes shall meet SB-338.

23-3TEST PROCEDURE

(a)Test to failure(visible collapse)by external hy-

drostatic pressure three full size specimens.

(b)The maximum allowable working pressure P shall

be determined by

P p F?B3??Y s Y a?

where

B p minimum collapse pressure,psi(kPa)

F p factor to adjust for change in strength due to

design temperature

p1.0for copper and copper alloy tubes

p S/S2for titanium alloy tubes

S p maximum allowable stress value for the tube

material at design temperature,as given in the

tables referenced in UG-23but not to exceed

S2,psi

S2p maximum allowable stress value for the tube

material at test temperature,as given in the ta-

bles referenced in UG-23,psi

Y a p actual average yield strength determined from

the un?nned length of the three specimens tested

at room temperature,psi(kPa)

Y s p speci?ed minimum yield strength at room tem-

perature,psi(kPa)

23-4CRITERIA

(a)The design of copper and copper alloy?nned

tubes to this Appendix shall meet the following require-

ments.

(1)External design pressure rating shall not exceed

700psi(4802kPa).

(2)Design temperature shall not exceed150°F

(66°C).

(3)Tubes shall have external and/or internal inte-

grally extended helical?ns and the sum of external

plus internal?ns shall be at least10?ns/in.(10?ns/

25mm).

(4)Dimensions and permissible variations shall be

as speci?ed in Item15of SB-359.

(b)The design of titanium alloy?nned tubes to this

Appendix shall meet the following requirements.

(1)External design pressure rating shall not exceed

3500psi(24010kPa).

23-4APPENDIX23—MANDATORY23-5

(2)Design temperature shall not exceed600°F (316°C).

(3)Tubes shall have external integrally extended helical?ns only and shall have at least10?ns/in.(10?ns/25mm).

(4)Dimensions and permissible variations shall be as speci?ed in item15of SB-359(Speci?cation for Copper and Copper Alloy Seamless Condenser and Heat Exchanger Tubes with Integral Fins).

(c)Additional requirements for copper,copper alloy, and titanium alloy tubes designed to this Appendix are as follows.

(1)Test specimens shall be identical in?n geome-try and pitch to production tubes.

(2)Test specimens of50outside diameters or more in length shall qualify all totally?nned lengths.

(3)Un?nned length at the ends or at an intermedi-ate section shall qualify that length and all lesser un?nned lengths.

(4)Nominal wall thickness under the?n and at the un?nned area shall qualify all thicker wall sections but with no increase in P.

(5)Outside diameter of the?nned section shall not exceed the outside diameter of the un?nned section.

(6)Tests shall be done in accordance with23-3, witnessed by and subjected to the acceptance of the Inspector.

23-5DATA REPORTS

When all the requirements of this Division and the supplemental requirements of this Appendix have been met,the following notation shall be entered on the Manufacturer’s Data Report under Remarks,“Con-structed in Conformance with Appendix23,External Pressure Design of Copper,Copper Alloy,and Titanium Alloy Condenser and Heat Exchanger Tubes With Integral Fins.”