ASME PTC 39-2005

(Revision and Redesignation of ASME PTC 39.1-1980)

Steam Traps

Performance Test Codes

A N A M E R I C A N N A T I O N A L S T A N D A R D

ASME PTC 39-2005

(Revision and Redesignation of ASME PTC 39.1-1980)

ASME PTC 39-2005

(Revision and Redesignation of ASME PTC 39.1-1980)

Steam Traps

Performance Test Codes

AN AMERICAN NATIONAL STANDARD

Three Park Avenue • New York, NY 10016

Date of Issuance: November 11, 2005

This Code will be revised when the Society approves the issuance of a new edition. There will be no addenda issued to ASME PTC 39-2005.

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The American Society of Mechanical Engineers Three Park Avenue, New York, NY 10016-5990

Copyright © 2005 by

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS

All rights reserved Printed in U.S.A.

CONTENTS

Forms

1. Data Log for Steam Loss Tests: No Loads or Condensate Load 6

2. Data Log for Capacity Test: Accumulator Level Measurement 9

3. Calculation of Condensate Capacity 10

4. Data Log for Intermittent Flow Capacity Test: Weigh Tank Measurement 11

5. Calculation of Condensate Capacity: Weigh Tank Measurement 12

6. Data Log for Intermittent Flow Capacity Test: Flowmeter Measurement 13

7. Calculation of Condensate Capacity: Flowmeter Measurement 14

8. Data Log for Air and Noncondensible Removal Test 15

9. Steam Loss Test Calculations 18

Mandatory Appendix

I Uncertainty Analysis 21

Nonmandatory Appendix

A Conversion Tables 30

NOTICE

All Performance Test Codes must adhere to the requirements of ASME PTC 1, General In- structions. The following information is based on that document and is included here for em- phasis and for the convenience of the user of the Code. It is expected that the Code user is fully cognizant of Sections 1 and 3 of ASME PTC 1 and has read them prior to applying this Code.

ASME Performance Test Codes provide test procedures that yield results of the highest level of accuracy consistent with the best engineering knowledge and practice currently available. They were developed by balanced committees representing all concerned interests and specify proce- dures, instrumentation, equipment-operating requirements, calculation methods, and uncertainty analysis.

When tests are run in accordance with a Code, the test results themselves, without adjustment for uncertainty, yield the best available indication of the actual performance of the tested equip- ment. ASME Performance Test Codes do not specify means to compare those results to contrac- tual guarantees. Therefore, it is recommended that the parties to a commercial test agree before starting the test, and preferably before signing the contract, on the method to be used for com- paring the test results to the contractual guarantees. It is beyond the scope of any Code to de- termine or interpret how such comparisons shall be made.

FOREWORD

The Performance Test Codes Supervisory Committee, at its June 1974 Administrative meeting, authorized the formation of a Code Technical Committee to explore the possibility of writing a test code on condensate removal devices. This committee was organized January 15, 1975. At its organizational meeting, the committee proposed the writing of two codes, PTC 39.1 on Conden- sate Removal Devices for Steam Systems and PTC 39.2 on Condensate Removal Devices for Air Systems. This proposal was approved by the Performance Test Codes Supervisory Committee.

The Code for Condensate Removal Devices for Steam Systems was approved by the Perfor- mance Test Codes Supervisory Committee on April 1, 1980. It was further approved as an Amer- ican National Standard by the ANSI Board of Standard Review on July 3, 1980.

This committee has been operating as PTC 39 Steam Traps.

The original document was a compromise which had three sets of existing test equipment to be utilized. We therefore satisfied the consensus standard.

The current document is generic and can fit other test platforms too.

The original publication was submitted without an uncertainty analysis. Mr. David Fisher of Armstrong Machine Works offered a magnificent theoretical treatise which is in our Appendix I.

It is a privilege to acknowledge the efforts of those who are currently not on the committee:

Thomas Alesson, Datron Systems — Nicholson Division Warren Brand, Yarway

Thomas W. Carr, Jr., Spirax Sarco Inc. Robert Collins, Watson Daniel Co.

Walter T. Deacon, Armstrong Machine Works Keith Foley, Celanese Canada, Inc.

Robert W. Henry, Salt River Project — Power Generation Systems Milton Hilmer, Sarco

David Kalix, Yarway Corp.

William Mashburn, Virginia Polytechnic Institute and State University — Mechanical Engineering Department

Elmer S. Monroe, DuPont

James W. Murdock, Mechanical Engineering of Drexel University Richard G. Obst, Spence Engineering Co., Inc./Nicholson Steam Trap William H. Schilling, Schilling Associates Inc.

William F. Sisson, Armstrong Machine Works Horst R. Thieme, Watson McDaniel Co.

We are aware that the preferred SI unit for time is seconds. However, the overwhelming cus- tomary unit in our industry is the capacity dimension of lb mass/hour. We have chosen to not include the rigorous usage but continue that which is common usage.

ASME PTC 39-2005 was adopted by the American National Standards Institute as an Ameri- can National Standard on May 5, 2005.

PERFORMANCE TEST CODE COMMITTEE PTC 39

ON STEAM TRAPS

(The following is the roster of the Committee at the time of approval of this Code.)

COMMITTEE OFFICERS

E. F. Gregg, Chair

M. A. Brookes, Secretary

COMMITTEE PERSONNEL

S. M. Bisgrove, Spence Engineering Co., Inc.

M. A. Brookes, The American Society of Mechanical Engineers

E. F. Gregg, Consulting Engineer

M. P. Hellman, Armstrong International Inc.

D. W. Fischer, Alternate, Armstrong International Inc.

W. E. Johnston, WEJ Energy Management Specialists, Inc.

S. J. Korellis, Dynegy Midwest Generation

A. A. Kornhauser, Virginia Tech

BOARD ON PERFORMANCE TEST CODES

OFFICERS

J. G. Yost, Chair

J. R. Friedman, Vice Chair

S. D. Weinman, Secretary

BOARD PERSONNEL

P. G. Albert, General Electric Co.

R. P. Allen, Consultant

J. M. Burns, Burns Engineering

W. C. Campbell, Southern Co. Services

M. J. Dooley, Alstom Power

A. J. Egli, Alstom Power

J. R. Friedman, Siemens Westinghouse Power Corp.

G. J. Gerber, Praxair, Inc.

P. M. Gerhart, University of Evansville

T. C. Heil, Consultant

R. A. Johnson, Safe Harbor Water Power Corp.

T. S. Jonas, Tenaska, Inc.

D. R. Keyser, Information Network Systems, Inc.

S. J. Korellis, Dynegy Midwest Generation

M. P. McHale, McHale & Associates, Inc.

P. M. McHale, McHale & Associates, Inc.

J. W. Milton, Environmental Systems, Corp.

S. P. Nuspl, Babcock & Wilcox, Inc.

A. L. Plumley, Plumley Associates

R. R. Priestley, General Electric Co.

J. A. Rabensteine, Environmental Systems Corp.

J. W. Siegmund, Sheppard T. Powell Associates

J. A. Silvaggio, Jr., Siemens Demag Delaval Turbomachinery

W. G. Steele, Jr., Mississippi State University

S. D. Weinman, The American Society of Mechanical Engineers

J. C. Westcott, Westcott Enterprises, Inc.

W. C. Wood, Duke Power Co.

J. G. Yost, Sargent & Lundy

CORRESPONDENCE WITH THE PTC 39 COMMITTEE

General. ASME Codes are developed and maintained with the intent to represent the consen- sus of concerned interests. As such, users of this Code may interact with the Committee by re- questing interpretations, proposing revisions, and attending Committee meetings. Correspon- dence should be addressed to:

Secretary, PTC 39 Standards Committee

The American Society of Mechanical Engineers Three Park Avenue

New York, NY 10016-5990

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 de- scription of the reasons for the proposal, including any pertinent documentation.

Interpretations. Upon request, the PTC 39 Committee will render an interpretation of any re- quirement of the Code. Interpretations can only be rendered in response to a written request sent to the Secretary of the PTC 39 Standards Committee.

The request for interpretation should be clear and unambiguous. It is further recommended that the inquirer submit his/her request in the following format:

Subject: Cite the applicable paragraph number(s) and the topic of the inquiry.

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 require- ment suitable for general understanding and use, not as a request for an ap- proval of a proprietary design or situation. The inquirer may also include any plans or drawings which are necessary to explain the question; however, they should not contain proprietary names or information.

Requests that are not in this format will be rewritten in this format by the Committee prior to being answered, which may inadvertently change the intent of the original request.

ASME procedures provide for reconsideration of any interpretation when or if additional in- formation that might affect an interpretation is available. Further, persons aggrieved by an in- terpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not “approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity. Attending Committee Meetings. The PTC 39 Standards Committee regularly holds meetings, which are open to the public. Persons wishing to attend any meeting should contact the Secre-

tary of the PTC 39 Standards Committee.

INTRODUCTION

This Code provides for the testing of steam traps in order to determine performance charac- teristics. It is based on the use of accurate instrumentation and the best analytical and measure- ment procedures currently available.

A study of the Code on General Instructions, PTC 1, is recommended as an introduction to es- sential procedures necessary for the proper use of this Code. The mandatory requirements con- tained therein are incorporated in this Code in Section 3.

The Code on Definitions and Values, PTC 2, defines certain technical terms and numerical con- stants, and their use is mandatory when applicable.

Reference is made to Performance Test Code Supplements on Instruments and Apparatus, PTC 19 series (abbreviated I&A), for general information and instructions on instrumentation. The specific directions of this Code, however, shall prevail for any instrument, procedure, or meas- urement which may differ from that given in another ASME publication.

This Code is recommended for use in conducting acceptance tests of steam traps. If so used, any deviations from Code procedure must be agreed upon in writing. In the absence of any writ- ten agreement, the code requirements shall be mandatory.

ASME PTC 39-2005

STEAM TRAPS

Section 1

Object and Scope

1. SCOPE

   This Code covers steam traps which are devices used for removing condensate and noncondensibles from steam systems.

   
   

2. OBJECT

   The purpose of this Code is to specify and define the practice of conducting tests of steam traps to determine: (a) steam loss, under specified conditions. This test procedure does not account for convection and radia-

   tion losses. These can be determined separately.

   1. condensate discharge capacity, for specified con- ditions of saturated and subcooled condensate and back pressure.

   2. ) air and noncondensible gas removal capacity, un- der specified conditions.

      
      

3. UNCERTAINTY ANALYSIS

This Code includes the methods and examples to de- termine the uncertainty of the tests performed in accor- dance with it. This Committee prefers to define the test instrumentation and limit the allowable data fluctua- tions. This is equivalent to putting an upper limit on the allowable post-test uncertainty and ensures the validity of the test.

This Committee suggests that the post-test uncer- tainty should not exceed the following:

Quantity Uncertainty

Condensate discharge rate less than 200 lbm/hr 10% (91 kg/h)

Condensate discharge rate 200 lbm/hr or greater 5% (91 kg/h)

Air discharge rate 10%

Steam loss rate greater than 20 lbm/hr (9.1 kg/h) 10% Steam loss rate 20 lbm/hr (9.1 kg/h) down to 15%

5 lbm/hr (2.3 kg/h)

Steam loss rate 5 lbm/hr (2.3 kg/h) down to 25% 1 lbm/hr (450 g/h)

However, the steam loss calculations involve the dif- ferences of very large numbers and at low steam loss rates, the post-test uncertainty can become very large.

Section 2

Definitions and Descriptions of Terms

1. GENERAL

   For terms and definitions not included in this Section, reference should be made to ASME PTC 2, Code on Definitions and Values.

   
   

2. STEAM TRAP

   A device which permits the removal of condensate and air and other noncondensible gases, for steam sys- tems at or below saturated steam temperature, and pre- vents or limits the discharge of live steam.

   
   

3. CAPACITY OF A STEAM TRAP

   The amount of condensate per unit time which will be discharged continuously from the steam trap under specified conditions of pressure differential and inlet subcooling. Capacity is expressed in units of pounds mass per hour or kilograms per hour.

   
   

4. PRESSURE

   Pressure is expressed in units of pounds force per square inch or pascals.

   1. Absolute pressure is the algebraic sum of the at- mospheric pressure and gage pressure.

   2. Atmospheric pressure is the force per unit area ex- erted by the atmosphere. Standard atmospheric pres- sure is 760 mm of mercury at 0°C. This is equivalent to

      101.325 kPa and 14.696 psia.

   3. Gage pressure is pressure measured with respect to the atmospheric pressure.

   4. Inlet pressure is the gage pressure measured at the steam trap inlet.

   5. Discharge pressure is the gage pressure measured at steam trap outlet.