ASME SEC VIII D3 NMA APP-H.pdf

APPENDIX H — NONMANDATORYOPENINGS AND THEIR REINFORCEMENT

H-100 SCOPE

The guidelines contained in the Appendix providefor a satisfactory design in the vicinity of openings inthe pressure shell, under pressure loading only, onthe basis of opening shape, area replacement, and itsdistribution. The requirements of Articles KD-2, KD-3, and KD-4 must also be satisfied. These guidelinesdo not include design requirements for piping loadsthat may be imposed on the nozzle and/or shell portionand that may be added to the pressure loadings.

These guidelines apply only to openings with integralreinforcement.

H-101 Dimensions and Shape of Openings

Openings may be circular, or elliptical, as resultsfrom the intersection of circular cylinders and circularvessels, provided:

(a) the ratio of the diameter along the major axisto the diameter along the minor axis of the finishedopening is 1.5 or less;

(b) the ratio d/DI ≤ 0.50, whered is the largestinside diameter of the opening andDI is the insidediameter of the opening;

(c) the arc distance measured between the centerlinesof adjacent nozzles along the inside surface of thevessel is not less than three times the sum of theirinside radii for openings in a head, or along thelongitudinal axis of a vessel is not less than two timesthe sum of their inside radii for openings along thecircumference of a cylindrical vessel. When two nozzlesin a cylindrical vessel are neither in a longitudinal linenor in a circumferential arc, their centerline distancealong the inside surface of the vessel should be suchthat ! (,c/2)2 + (,,/3)2 is not less than the sum oftheir inside radii, where,c is the component of thecenterline distance in the circumferential direction and,, is the component of the centerline distance in thelongitudinal direction;

(d) reinforcement is provided around the edge of theopening in amount and distribution such that the area

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requirements for reinforcement are satisfied for allplanes through the center of the opening and normalto the vessel surface as stipulated in H-120.

Some high pressure connections are shown in Fig.H-101.

H-110 CIRCULAR OPENINGS NOTREQUIRING REINFORCEMENT

Circular openings need not be provided with rein-forcement if all of the following requirements aresatisfied.

(a) A single opening has a diameter not exceeding0.2! Rmt, or if there are two or more openings withinany circle of diameter 2.5! Rmt, then the sum of thediameters of such unreinforced openings should notexceed 0.25! Rmt .

(b) No two unreinforced openings should have theircenters closer to each other, measured on the insideof the vessel wall, than 1.5 times the sum of theirdiameters.

(c) No unreinforced opening should have its centercloser than 2.5! Rmt to the edge of a locally stressedarea in the shell, whereRm is the mean radius andtis the nominal thickness of the vessel shell or head atthe location of the opening(s); locally stressed areameans any area in the shell where the primary localmembrane stress exceeds 0.73Sy, but excluding thoseareas where such primary local membrane stress is dueto an unreinforced opening.

H-120 REINFORCEMENT FOR OPENINGSIN SHELLS AND FORMED HEADS

(a) Design for Internal Pressure.The total cross-sectional area of reinforcementA required in any givenplane for a vessel under internal pressure should benot less than

COPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling ServicesCOPYRIGHT American Society of Mechanical EngineersLicensed by Information Handling Services

Fig. H-101 2001 SECTION VIII — DIVISION 3

FIG. H-101 STRAIGHT DRILL CONNECTIONS FOR01

THICK WALLED CYLINDERS

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H-120 APPENDIX H — NONMANDATORY H-130

FIG. H-120.1 CHART FOR DETERMINING VALUE OF F

A p dtrF (1)

wheredp diameter in the given plane of the finished open-

ing, in.trp minimum thickness which meets the require-

ments of KD-230 in the absence of the open-ing, in.

Fp 1.00 when the plane under consideration is inthe spherical portion of a head or when thegiven plane contains the longitudinal axis of acylindrical shell. For other planes through ashell, use the value ofF determined from Fig.H-120.1.

(b) Design for External Pressure. The reinforcementrequirements for openings in vessels subject to externalpressure need be only 50% of that required in Eq. (1)above.

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H-130 REINFORCEMENT FOR OPENINGSIN FLAT HEADS

Flat heads that have an opening with a diameter thatdoes not exceed one-half of the head diameter shouldhave a total cross-sectional area of reinforcement notless than that given by the equation

A p 0.5dtr

wheredp diameter of the finished opening, in.trp minimum thickness which meets the require-

ments of KD-640 in the absence of the open-ing, in.


H-140 2001 SECTION VIII — DIVISION 3 H-150

H-140 LIMITS OF REINFORCEMENT

The boundaries of the cross-sectional area in anyplane normal to the vessel wall and passing throughthe center of the opening within which metal shouldbe located in order to have value as reinforcement aredesignated as the limits of reinforcement for that planeand are as described in H-141 and H-142.

H-141 Boundary Along Vessel Wall

Two requirements on the limits of reinforcementmeasured along the midsurface of the nominal wallthickness should be met as follows.

(a) 100% of the required reinforcement should bewithin a distance on each side of the axis of theopening equal to the greater of the following:

(1) the diameter of the finished opening in thecorroded condition;

(2) the radius of the finished opening in the cor-roded condition plus the thickness of the vessel wallplus the thickness of the nozzle wall.

(b) Two-thirds of the required reinforcement shouldbe within a distance on each side of the axis of theopening equal to the greater of the following:

(1) r + 0.5! Rmt, whereRm is the mean radius ofshell or head,t is the nominal vessel wall thickness,and r is the radius of the finished opening in thecorroded condition;

(2) the radius of the finished opening in the cor-roded condition plus the thickness of the vessel wallplus the thickness of the nozzle wall.

H-142 Boundary Normal to Vessel Wall

The limits of reinforcement, measured normal to thevessel wall, should conform to the contour of thesurface at a distance from each surface equal to thefollowing limits.

(a) For Fig. H-142, sketches (a) and (b), the limitis the larger of 0.5! rmtn + K and 1.73x + 2.5tp + K,but this limit should not exceed either 2.5t or L +2.5tp, where

Kp 0.73r2 when a transition radiusr2 is used andthe smaller of the two legs when a fillet weldtransition is used, in.

Lp length along nozzle with thickness oftn plustransition length, in.

rp inside radius of nozzle, in.rmp mean radius of nozzle, in.

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p r + 0.5tn

r2p transition radius between nozzle and vesselwall, in.

tp nominal vessel thickness, in.tnp nominal nozzle thickness, in.tpp nominal thickness of connecting pipe, in.xp slope offset distance, in.p tn − tp

(b) For Fig. H-142, sketch (c):(1) When 45 deg≥ u ≥ 30 deg, the limit is the

larger of 0.5! rmt′n and L′ + 2.5tp ≤ t.(2) When u < 30 deg, the limit is the larger of

0.5! rmt′n and 1.73x + 2.5tp ≤ 2.5t, whereL′p length of tapered section along nozzle, in.rp inside radius of nozzle, in.

rmp r + 0.5t′nt′np tp + 0.667xup angle between vertical and slope (45 deg or

less), degOther terms are given in H-142(a).

(c) For Fig. H-142, sketch (d), the limit is the largerof 0.5 ! rmtn + te and 2.5tn + te ≤ 2.5t. In no casecan the thicknesste used to establish the limit exceed1.5t or 1.73W, where

Wp width of added reinforcing element, in.tep thickness of added reinforcing element, in.

Other terms are given in H-142(a).

H-150 METAL AVAILABLE FORREINFORCEMENT

Metal may be counted as contributing to the areaof reinforcement called for in H-120 and H-130 providedit lies within the area of reinforcement specified in H-140, and should be limited to material which meetsthe following requirements:

(a) metal forming a part of the vessel wall whichis in excess of that required by the static designrequirements of Article KD-2, and is exclusive ofcorrosion allowance;

(b) similar metal in the nozzle wall, provided thenozzle is integral with the vessel wall or is joined toit by a full-penetration weld;

(c) all reinforcement metal should be fully continuouswith the shell, nozzle, or combination thereof;

(d) the metal to be included as reinforcement underH-150(b) and (c) should meet the following limit:


APPENDIX H — NONMANDATORY Fig. H-142

FIG. H-142 NOZZLE NOMENCLATURE AND DIMENSIONS(Depicts Configuration Only. See Article KD-11 for Details of Construction.)

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H-150 2001 SECTION VIII — DIVISION 3 H-151

|(ar − av)DT| ≤ 0.0008

wherearp mean coefficient of the thermal expansion of

reinforcing metal at design temperature, in./in. °F

avp mean coefficient of thermal expansion of vesselmetal at design temperature, in./in. °F

DTp operating temperature range from 70°F to theoperating temperature, or the difference fromthe lowest operating temperature to the highestoperating temperature, if greater

For designs exceeding this limit, no credit should betaken for reinforcing potentially available in the nozzleneck within the limits of reinforcement.

NOTE: It is likely that designs exceeding the limit in (d) will notmeet the desired results of the required fatigue analysis.

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(e) metal available for reinforcement should not beconsidered as applying to more than one opening.

H-151 Strength of Reinforcement Material

In no case should the yield strength of the nozzlematerial be less than 80% of the yield strength of thevessel wall at the design temperature.

If material with a lower yield strength is used, thearea provided by such material should be increased inproportion to the inverse ratio of the yield strength ofthe nozzle and the vessel wall material. No reductionin the reinforcement requirement may be made if thenozzle material or weld metal has a yield strengthhigher than that of the material of the vessel wall. Thestrength of the material at the point under considerationshould be used in fatigue analyses.


ASME SEC VIII D3 NMA APP-H.pdf

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