SECTION 5 MECHANICAL STANDARDS TEMA CLASS R C B

RCB-s.23 PACKING MATERIALPurchaser shall specify packing material which is compatible with the shell side processconditions.

RC8.5.24 FLOATING TUBESHEET SKIRTThe floating.tubesheet skirt normally shall enend outward. When the skirt must extendinward, a suitable method shall be used to prevent stagnant areas betuyeen the sheli sidenozzle and the tubesheet.

RCB-5.25 PASS PARTITION PI-ATESThe nominal thickness of floating head pass partitions shall be identical to those shown inParagraph RCB-9.13 for channels and tjonndts.

RCB-5.3 EXTERNALLY SEALED FLOAT|NG TUBESHEET (Type w)

RB-5.31 I.ANTERN RINGThe externally sealed floating tubesheet using square braided packing materials shall be usedonly for water, steam, air, lubricating oil, or si-mitdr seruices. Dirsign t6mperature shall notexceed 375 " F (191 " C) . Design pressure shall be limited according to Table RB-5.31 .

rABLE RB-5.31MAXIMUM DESIGN PRESSURE FOR EXTERNALLY SEALED

FLOATING TUBESHEETS

Nominal Shell Inside DiameterInches (mm)

Maximum Design PressurePSI (kPa)

6 - 2 42 5 - 4 24 3 - 6 061 - 100

(1s2-610)(63s-1067)

(1092-1524\(1549-2540)

(2068)(1 034)(517)(345)

3001507550

C-5.31 LANTERN RINGThe externally sealed floating tubesheet shall be used only for water, steam, air, lubricating oil,or similar services. Design temperature, pressure and shell diameter shall be limited by th-eservice, joint configuration, packing material and number of packing rings, to a maximumdesign pressure of 600 psi (4137 kPa). .

RCB-5.32 LEAKAGE PRECAUT]ONS

The design shall incorporate provisions in the lantern ring so that any leakage past thepacking will leak to atmosphere. When endless packing-rings are uded, one ring of packingshall be used on each side of the lantern ring. For braided packing materials with a seam. aminimum of two rings of packing shall be used on each side of the lantern ring, with theseams staggered during assembly.

RCB-s.33 PACKING MATERIALPurchaser shall specify packing materialwhich is compatible with the process conditions.

RCB-5.34 SPECIAL DESIGNS

Special designs incorporating other sealing devices may be used for the applications inParagraph RB-s.31 and C-5.31 or other special service requirements. Provisions for leakdetection shall be considered.

42 Standards Of The Tubular Exchanger Manufacturers Association

MECHANICAL STANDARDS TEMA CLASS R C B

RC8-6 GASKETS

RCB-6.1 TYPE OF GASKETS

SECTION 5

Gaskets shall be selected which have a continuous periphery with no radial leak paths. This shall notexclude gaskets made continuous by welding or other methAds which produce a homogeneousbond.

R-6.2 GASKET MATERIALSMetal jacketed or solid metal gaskets shall be used for internal floating head joints, all joints forpressures of -3Q0 psi (2068 kPa) and over, and for all joints in contact with hyilrocarbons. Othergasket materials may be specified by agreement behireen purchaser and manufacturer to meetspecial service conditions and flange design. When two gisketed joints are compressed by thesame bolting, provisions shall be made so that both gask-ets seal, 6ut neither gasket is crushed at therequired bolt load.

CB-6.2 GASKET MATERIALSFor design pressures of 300 psi (2068 kPa) and lower, composition gaskets may be used for externaljo_ints, unless temperature or corrosive nature of contained fluid indicates otherwise. Metaljacketed,filled or solid metal gaskets shall be used for all joints for design pressures greater than 30Opsi (2068kPa) and for internalffoating head joints. Other gasket materi-als'may be splcified by agreemenibetween purchaser and manufact[rer to meet special service conditions ahd flange iJes-ign. Whentwo gasketed ioints are compressed by the same bolting, provisions shall be made so that bothgaskets seal, but neither gasket is crushed at the required bolt load.

RC8-6.3 PERIPHERAL GASKETSRC-6.31

The minimum width of peripheral ring gaskets for external joints shall be 3/8" (9.5 mm) forshell sizes through 23 inches (58a mm) nominal diameter and 1 /2" (12.7 mm) for all largershell sizes.

8-6.31

The minimum width of peripheral ring gaskets for external joints shall be 3/8" (9.5 mm) forshell sizes through 23 inches (584 mm) nominal diameter and 1 /2" (12.7 mm) for all largershell sizes. Full face gaskets shall be used for all cast iron flanges.

RCB-6.32

The minimum width of peripheral ring gaskets for internal joints shall be 1/4" (6.4 mm) for allshell sizes.

R-6.33

Peripheral gasket contact surfaces shall have a flatness tolerance ot* 1/32" (0.8 mm)maximum deviation from any reference plane. This maximum deviation shall not occur in lessthan a 20 " (0.3 Rad) arc.

cB-6.33Flatness of peripheral gasket contact surfaces shall be sufficient to meet the requirements ofParagraph RCB-1.3.

RCB-6.4 PASS PARTITION GASKETSThe width of gasket web for pass partitions of channels, bonnets, and floating heads shall be not lessthan 1/4" (6.+-mm) for shell sizes ihrough 23 inches (58a mm) nominal diameter and not less than3/8" (9.5 mm) for all larger shell sizes.

R-6.5 GASKET JOINT DETAILS

Gasketed joints shall be of a confined type.

Standards Of The Tubular Exchanger Manufacturers Association 43