Eig hth Editio n - 1994

Printed in U.S.A. by

Ame rican Gas Association Labo rato ries 8501 East Pleasan t Valley Road

Cl eve land , Ohio 44131

Approved

Feb ruary 14, 1994 AMERICAN NATIO NAL

STAND ARDS INS TIT UTE, INC.

Copy right © 1994 , AMERICAN GAS ASS OCIATIO N

Pe rmissio n is granted to repu blis h material he rein in laws or ordinances , and in regu lations , administ rative orde rs, or simi lar documents iss ued by pub li c autho riti es. Those desi ring pe rmissio n f o r othe r r epu bli cation shou l d consu lt t he A me ri can G as A ssociation L abo r ato ri es , 8501 East P l easan t V a ll ey Road , Cl eve land , Ohio 44131 .

Printed in U.S.A.

PREFACE

This tex t out li nes fundamen tal crit eria for the ins tallatio n of domestic gas conve rsion b urne rs i n house hea ti ng and w ate r hea ti ng app li ances . The provisions are the cumu lative resu lt s of yea rs of expe ri ence in the ins tallatio n of such devices in cent ral hea ti ng equip men t ori gina ll y utilizi ng so li d fue l or oi l and are intended to promote pub li c safety by providing guide li nes for the safer and more satis facto ry utilizatio n of gas .

Du ring the prepa ration of thes t guide lines , due conside ration w as given to the fact tha t they are to be na tio na l in scope and su ffici en tly gene ral to encompass conditions ex isti ng in va ri ous geog raphic locations . Fu rt he rmo re, those conve rsion burne rs ins tall ed shou ld be in full comp liance wit h the speci fications for safe ope ration , substantia l and durable const ruc tio n and acceptab le pe rf or mance as contained i n t he Standa rd for Domestic Gas Conve rsion Burners, ANSI Z21.17.

As prog ress is made in the utilizatio n of gas , rev isio ns to these guide li nes may become necessa ry. When they are beli eved desi rable, r ecommenda tio ns shou l d b e f o r w a r ded to t he C ha ir man o f Acc red it ed Standa rds Committee Z21, 8501 East Pleasan t Vall ey Road , Cl eve land , Ohio 44131 .

Safe and satis facto ry ope ration of a ins tallatio n of domestic gas conve rsion burne rs depends to a grea t ex ten t upon its prope r ins tallatio n, and it shou ld be ins tall ed in acco rdance w it h the Nationa l Fue l Gas Code , ANSI Z223.1; manu factu rers’ installatio n ins tr uc tio ns and loca l mun icipal codes .

Use rs of this Ame ri can Nationa l Standa rd are advised that the devices /products /activities w it hin its scope may be sub jec t to regu lation at the Fede ral state or loca l leve l. Use rs are strong ly urged to inves tigat e this possibi lit y through app rop ri ate channe ls. In the even t of a con fli ct with this standa rd, the Fede ral, state or loca l regu lation shou ld be follo wed.

CAUTIO N NOTIC E: This Ame ri can Nationa l Standa rd may be rev is ed or wit hdrawn at any ti me. The procedu res of the Ame ri can Nationa l Standa rds Instit ute, Inc., require that action be tak en to reaffirm, rev is e or wit hd raw this standa rd no late r than five (5) yea rs from the date of app rova l. Purchase rs of Ame ri can Nationa l Standa rds may rece iv e cu rr en t informa tio n on all standa rds by ca lli ng or writi ng the Ame ri can Nationa l Standa rds Ins tit ute, Inc., 11 West 42 nd Stree t, Ne w York, N.Y. 10036 , (212) 642-4900 .

EFFE CTIV E DATE: An organization us i ng t h is standa rd for product eva lua tio n as a pa rt of its ce rti fication prog ram w ill norma lly es tablis h the date by whic h all products ce rtifi ed by that organization shou ld comp ly wit h this standa rd.

HISTORY OF THE DEVELOPMEN T OF STANDARDS FOR INSTALLATIO N OF DOMES TIC GAS

CONVERS ION BURNERS

(This History is informat ive and is not part of the stan dard.)

At a mee ti ng of the Ame ri can Gas Association (A.G.A.) Approva l Requiremen ts Committee in Ju ly, 1929 , it was decided to form a subcommittee to p r epa r e a standa r d f o r t he i ns tallatio n o f conve rsion burne rs. The subcommittee , organized soon the reafter, deve loped an ins tallatio n code to guide gas company fitt ers, hea ti ng and piping cont racto rs, and conve rsion burner manu factu rers in the safe and effici en t use of gas conve rsion burners in house and wate r hea ti ng app li ances ori gina lly designed for utilizatio n of othe r typ es of fuels.

On Septembe r 11, 1930 , the A.G.A. App rova l Requir emen ts Committee became Sectiona l Committee Z21 of the Ame ri can Standa r ds Association . Consequent l y, t he Subcommittee on Requir emen ts for Ins tallatio n of Conve rsion Bu rne rs became a subcommittee of the Z21 Committee .

A draft of this ins tallatio n standa rd for conve rsion burners was t en tativ e ly accepted by t he Z21 Committee for release to t he indus try in Feb ruary, 1931 and subsequent ly pri nted and dist rib uted on April 28 of the same yea r. After the usua l review and comment pe ri od had elapsed , the ten tativ e standa rd w as rev is ed by the subcommittee in the li ght of comments rece iv ed and a mod ified text was app roved by the Z21 Committee on Septembe r 11, 1931 .

T h is p r oposed standa r d w as fo r w a r ded to t he Ame ri can Standa rds Association for acceptance as an Ame ri can Standa rd, but because of differences between it and the Nationa l Fire Protection Association ’s (NF PA) Recommended Good Practice Requir emen ts for the Ins tallatio n, Maintenance and Use of Pipi ng and Fittings for City Gas, the conve rsion burner ins tallatio n text was referr ed ba ck for furt her conside ration . The subcommittee me t on March 4, 1932 and proposed mino r changes to con form w it h the NF PA code , whereve r possib le, and the rev is ed text was subsequent ly app roved by t he Z 21 C ommittee . A f u rt he r r ev isio n p r oposed by t he subcommittee was app roved by the Z21 Committee at its May 20, 1932 mee ti ng. The resu lt ant standa rd was app roved as an Ame ri can Standa rd by the Ame ri can Standa rds Association in Janua ry 4, 1933 .

Subsequent ed itio ns of the conve rsion burne r ins tallatio n standa rd were app roved by the Ame ri can Standa rds Association on

i

Feb r ua r y 23 , 1940 , Septembe r 21 , 1948 , A ugus t 12 , 1958 and

Novembe r 3, 1965 .

On Augus t 24, 1966 , the Ame rican Standa rds Association was recons tit uted as the United States of Ame ri ca Standa rds Instit ute w hic h, in turn, w as renamed the Ame ri can Nationa l Standa rds Instit ute, Inc ., on Octo ber 6, 1969 . As a resu lt, the sixth editio n of the standa rd was app roved as an Ame ri can Nationa l Standa rd on Decembe r 17, 1971 . The sixth ed itio n of the standa rd was rea ffir med by the Ame ri can Nationa l Standa rds Ins tit ute on Janua ry 20, 1977 .

A t its Ju l y 10 , 1980 mee ti ng , t he conve r sion b u r ne r subcommittee had agreed that a thorough review of Z21.8 was in order and that a redraft of Z21.8 shou ld be prepa red by a working group for conside ration by the subcommittee . The draft standa rd, w hic h w as reo rganized and upda ted to be consistent w it h the Nationa l Fue l Gas Code , ANSI Z223 .1, was dist rib uted for rev iew and comment du ri ng Janua ry 1982 . The subcommittee recons id ered the proposed standa rd at its May 11-13, 1982 mee ti ng in li ght of comments rece iv ed and , wit h some mod ifications , recommended it to t he Z21 Committee , w h ic h app r oved it at its Ap ril 7, 1983 mee ti ng. The seventh ed itio n of the conve rsion burner ins tallatio n standa rd was app roved as an Ame ri can Nationa l Standa rd by the Ame ri can Nationa l Standa rds Ins tit ute, Inc., on March 2, 1984 .

This, the eig hth ed itio n of the conve rsion burne r ins tallatio n standa rd was app roved as an Ame ri can Nationa l Standa rd by the Ame ri can Nationa l Standa rds Ins tit ute, Inc., on Feb ruary 14, 1994 .

Prev io us ed itio ns of the conve rsion burner ins tallatio n standa rd, and addenda t he r e to , app r oved by ANS I o r its p r edecesso r organizations are as follo ws:

NOTE: This 1994 ed itio n of Z21.8 inco rpo rates changes to the 1984 ed itio n of Z21.8, and addenda the reto . Changes , othe r than ed itorial , are denoted by a ve rti cal li ne in the margin .

ACC RED ITED STANDARDS COMMITT EE Z21

HOWARD I. FORMAN, Cha ir man THEODORE C. LEMOFF, Vic e Cha ir man

ALL EN J. CALLA HAN, Administ rative Sec retary (Non -Voting )

RE PRESEN TING AIR-COND ITIO NING CONTRACTO RS OF AMERICA:

(Liaiso n Rep.)

James P. No rri s

RE PRESEN TING AMERICAN GAS ASS OCIATIO N:

Cha rl es D. Applequist Mic hae l E. Griffin Dan Ha nsen

John R. Pe ak Jack D. Rea Billy R. Ware

RE PRESEN TING AMERICAN HOME ECONOMIC S ASS OCIATIO N:

Frances Gailey, Ph.D.

RE PRESEN TING AMERICAN PUB LIC GAS ASS OCIATIO N:

Rob ert S. Cave

RE PRESEN TING ASS OCIATIO N OF HOME APP LIANCE MANUFACT URERS :

Earl T. Rhineha rt

Accred it ed Standa rds Committee Z21 Mem bership

RE PRESEN TING THE CANADIAN GAS ASS OCIATIO N:

Kenne th Bales

Kevin Campbe ll (Alterna te)

RE PRESEN TING CONSU MERS UN ION:

George Pap ritz

RE PRESEN TING FACTO RY MUTUAL SYSTEM:

Armand V. Brandao

RE PRESEN TING GAS APP LIANCE MANUFACT URERS ASS OCIATIO N, INC.:

Danie l J. Canc li ni

Alb ert B. Cham berlain Willia m E. Da lt on

Jim Goins

Mic hae l F. Grosso

J. R. Katchka James Mull en Er nes t Wenc zl

RE PRESEN TING GENER AL SERVIC ES ADMINISTRATIO N, FEDER AL SU PP LY SERVIC E:

Dennis Davis

Chri stophe r Pollock (Alterna te)

IND IVIDUAL MEMBERS:

Ho ward I. Forman

R. Mic hae l Marti n (Liaiso n Rep.) Vail P. Garvin

Accred it ed Standa rds Committee Z21 Mem bership

RE PRESEN TING INTERN ATIO NAL ASS OCIATIO N OF PLUMBING AND MECHANICAL OFF ICIAL S:

Jack All en

RE PRESEN TING MECHANICAL CONTRACTO RS ASSOCIATION OF AMERICA, INC.:

Willia m C. Abernathy

RE PRESEN TING NATIO NAL ASS OCIATIO N OF PLUMBING- HEATING AND COOLI NG CONTRACTO RS:

Terr ell D. Mose ley

Rob ert Warr en (Alterna te)

RE PRESEN TING NATIO NAL ELECTRICAL MANUFACT URERS ASS OCIATIO N:

G. E. Will ert

Alan R. Ande rson (Alterna te)

RE PRESEN TING NATIO NAL FIRE PROTECTIO N ASS OCIATIO N:

Theodo re C. Lemo ff

RE PRESEN TING NATIO NAL PROPANE GAS ASS OCIATIO N:

Ty V. Lotz

RE PRESEN TING NATIO NAL INS TIT UTE OF STANDARDS AND TECHN OLOGY, U.S. DEPARTMEN T OF COMMERCE:

Walt er G. Leig ht

Accred it ed Standa rds Committee Z21 Mem bership

RE PRESEN TING NAVAL FACILITI ES EN GINEER ING COMMA ND,

U.S. DEPARTMEN T OF THE NAVY:

Danny C. Mui

W. E. Watkins (Alterna te)

U.S. DEPARTMEN T OF DEFENSE - OFF ICE OF ASSISTANT SECRETARY OF DEFENSE :

Gr eg Scunden

RE PRESEN TING SOUTHERN BU ILDING CODE CONGRESS :

(Appointment Pen ding )

RE PRESEN TING UNDER WRITERS LABORATORIES INC.:

Henry Jones

RE PRESEN TING U.S. CONSU MER PRODU CT SAFETY COMMI SS ION:

(Liaiso n Rep.)

Dona ld W. Switz er

RE PRESEN TING U.S. DEPT. OF ENER GY:

(Liaiso n Rep.)

Er nie Freeman

RE PRESEN TING U.S. DEPT. OF HEALTH AND HUMAN SERVIC ES:

(Appointment Pen ding )

RE PRESEN TING U.S. DEPT. OF HOUSING AND URBAN DEVELOPMEN T:

(Liaiso n Rep.)

Victor J. Fe rrante

SUB COMMITT EE ON STANDARDS FOR DOMES TIC GAS CONVERS ION BURNERS

TERR ANCE C. SLABY, Cha ir man

RE PRESEN TING GAS COM PANIES:

Danie l F. Cole

Er nes t W. Koche r Rob ert L. Reif

RE PRESEN TING MANUFACT URERS :

Ric hard A. Cunha Gordon Dau ley Carl H. Kolb

R. A. Mackintosh Melvin J. Myers Terrance C. Slaby

CONTEN TS

Page

PART 1. SCOPE

1.1 App li ca bility . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Safe and Satis facto ry Operation 1

1.3 Ins tallatio n . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

PART 2. VISUAL INS PECTIO N

1. Air for Combustion and Ven tilatio n 3

2. Combustion Cham ber Liner 8

2.3 Ven t Connecto r . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Chimney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.5 Accesso ri es . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1. Ven t Dampe r Devices 8

2. El ec trical Supp ly Conside rations 8

2.8 Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

PART 3. SELECTIO N AND SIZING OF CONVERS ION BURNER 3.1 Gene ral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1. Typica l Conve rsion Burner Types 9

2. App li ance Design Featu res 10

3. Heat Loss Dete rmina tio n 10

4. Inpu t Rat e Dete rmina tio n 10

5. Preli minary Burner Selec tio n 11

6. Fina l Burner Selec tio n 19

PART 4. PRE PARATIO N OF EXISTING HEATING PLANT

1. Cl ean ing 21

2. Recond itio ning 21

3. Combustion Cham ber Linings 21

4. Wate r Hea ti ng Coils 22

5. Use of Asbestos 22

PART 5. PRE PARATIO N OF EXISTING HEATING SYSTEM

1. Chimneys 23

2. Ven t Connecto r and Chimney Sizing 23

3. Pitc h 24

4. Reve rtibl e Flues 25

5. Suppo rt and Cl earance 25

6. Draft Hoods and Baromet ri c Draft Regu lato rs . . 25 5.7 Ven t Connection 28

CONTEN TS (Continued )

AMERICAN NATIO NAL STANDARD FOR INSTALLATIO N OF DOMES TIC

GAS CONVERS ION BURNERS

PART 1 SCOPE

1. App li ca bility .

   
   

   This stan dard applies to the insta llat ion of a conversion burn er with an input of 400,000 Btu per hour (117 228 W) or less and design certified as complyi ng with th e Stan dar d for Domestic Gas Conversion Burners, ANS I Z21.17.

   
   

   This stan dard, in conjunction with local codes or, in the abse nce of local codes , with th e National Fuel Gas Code, ANS I Z223.1, is applicable to situat ions where an appliance is to be convert ed to gas with a conversion burn er, provided it can be demonstrat ed un der Part s 2 and 3 that such a conversion can be ma de with safety, economy and in the bes t interes t of the consum er.

   
   

   All references to “psi” thr oughout this stan dard are to be considered gage press ure, un less otherwise specified.

   
   

   Exhibi t conta ins a list of stan dar ds specifically referenced in th is stan dar d, an d sources from which th ese reference stan dar ds ma y be obtained.

   
   

2. Safe and Satis facto ry Operation .

   
   

   Once the decision has bee n ma de to convert an appliance from another fuel to gas, safe and satisfactory operat ion will be depe ndent on a num ber of factors. Among th ese are:

   
   

   1. Proper ana lysis of the feasibili ty of conversion;

      
      

   2. Proper selection of the burn er to be used;

   3. Proper selection of the draft hood or barometric draft regulator to be used;

      
      

   4. Following the instru ctions conta ined in this stan dard; and

      
      

   5. Following the insta llat ion instru ctions provided with the conversion burn er.

      
      

      For furth er informat ion or assistan ce, th e appliance manu factur er should be conta cted. In no case should the appliance be modified beyond the recomm endation of the appliance manu factur er. If the manu factur er cann ot be conta cted, the local gas supplie r should be consulted.

      
      

3. Ins tallatio n.

The responsibili ty for a safe and satisfactory insta llat ion is shar ed by th e agency determining th e feasibili ty an d selection of th e burn er, th e insta lle r, an d th e local auth ority ha ving jur isdiction. In man y ar eas a pe rm it is req uired. Ob ta ining th is pe rm it is th e resp onsibili ty of th e insta lle r. Maintenan ce and report ing of possible improper operat ion is the responsibili ty of the user. It is the responsibili ty of the insta lle r to inform the user of the corr ect operat ion and maintenan ce.

PART 2

VISUAL INS PECTIO N

Before p roceedi ng wi th th e r emoval of p art s from th e exis t ing appliance, a car eful inspection shall be ma de as to th e condition of th e appliance. This inspection shall be ma de for cracks or loose cement in heating sections, war ped doors an d door fram es, le aking plugs, an d any other condition which would mak e the convert ed appliance uneconomical or unsafe. Thorough exam inat ion of heat exchan gers sha ll show no evide nce of cracks or excessive corrosion. Boile rs sha ll show no signs of wat er leaka ge, evide nce of cracked sections, or excessive corrosion.

The furna ce and duct system in the furna ce room or vicinity sha ll be inspected to assure there are no open return regis ters or other openings which could allow combustion products to enter the circulating air supply duct system.

1. Air for Combustion and Ven tilatio n.

   
   

   1. Gene ral:

      
      

      1. The provisions of 2.1 apply to gas ut iliz ation equipment insta lled in buildings an d which require air for combustion, ventilation an d dilut ion of flue gases from with in the building. They do not apply to (1) direct vent equipment which is constru cted and insta lled so all air for combustion is obtained from the outside atm osp here and all flue gases ar e dischar ged to th e out side atm osphere, or (2) enclosed furna ces which incorporat e an int egra l total enclosure and use only outside air for combustion and dilut ion of flue gases.

         
         

      2. Equipment sha ll be insta lled in a locat ion in which the facilities for vent ilat ion permit satisfactory combustion of gas, proper vent ing and the maintenan ce of am bient temperatur e at safe limits un der norma l conditions of use. Equipment sha ll be locat ed so as not to interfere with proper circulation of air. When norma l infiltrat ion does not provide the necess ary air, outside air sha ll be intr oduced.

         
         

      3. In addition to air needed for combustion, process air sha ll be provided as required for: cooling of equipment or mat erial, contr olling dew point, heating, drying, oxidat ion or dilut ion, safety exhau st, odor contr ol and air for compressors.