LARGE DIAMETER STEEL FLANGES PRESSURE–TEMPERATURE RATINGS

PRESSURE–TEMPERATURE RATINGS

2.1 General

Pressure–temperature scores are greatest allowable working gage pressures, in bar sets, at the temperatures in degrees Celsius shown in Tables three thru

27 for the suitable subject material and sophistication designation.

Tables I-1 by means of I-25 of Mandatory Appendix I lists

stress–temperature scores with the aid of psi models for pressure on the temperature in tiers Fahrenheit. For intermediate temperatures, linear interpolation is allowed.

Interpolation among category designations is just not accepted.

2.2 Flanged Joints

A flanged joint is composed of separate and unbiased, in spite of the fact that interrelated, formula: the flanges, the

gasket, and the bolting, which are assembled via a further

outcome, the assembler. Proper controls will have to be exercised inside the determination and application for all of these

aspects to acquire a joint that has suited leak tightness. Assembly and tightening options, akin to managed bolt tightening, are described in ASME PCC-1.

2.3 Ratings of Flanged Joints

2.three.1 Basis. Pressure–temperature scores observe to

flanged joints that agree to the constraints on bolting

in para. five.three and on gaskets in para. 5.4, and which can be

made up according with impressive exercise for alignment

and assembly (see para. 2.2). Use of those rankings for

flanged joints not conforming to these barriers is the

duty of the person.

2.3.2 Mixed Flanged Joints. If the two flanges in a

flanged joint do not have the equal rigidity–temperature

ranking, the rating of the joint at any temperature is the

reduce of the 2 flange ratings at that temperature.

2.four Rating Temperature

The temperature proven for a corresponding drive

ranking is the temperature of the force containing shell

of the component. In primary, this temperature is the

related as that of the contained fluid. Use of a drive

rating reminiscent of a temperature apart from that of the contained fluid is the accountability of the consumer,

subject to the specifications of ideal codes and guidelines. For any temperature beneath −29°C (−20°F) the

rating can be no more beneficial than the score proven for

−29°C (−20°F). See additionally para. 2.5.three.

2.five Temperature Considerations

2.five.1 General. Use of flanges at either high or low

temperatures shall take into consideration the risk of

joint leakage via forces and moments evolved in

the attached piping or apparatus. Provisions in

paras. 2.5.2 and a couple of.five.3 are integrated as advisory with the

intention of lessening those disadvantages.

2.five.2 High Temperature. Application at temperatures within the creep stove will end in lowering bolt

loads as leisure of flanges, bolts, and gaskets takes

area. Flanged joints subjected to thermal gradients can even

likewise be field to cutting back bolt a lot. Decreased

bolt quite a bit scale back the means of the flanged joint to

maintain masses correctly with out leakage. At temperatures above two hundred°C (four hundred°F) for Classes 75 and 150, and

above 400°C (750°F) for different type designations, flanged

joints would expand leakage issues unless care is taken

to preclude imposing severe outside rather a lot and/or excessive

thermal gradients.

2.five.3 Low Temperature. Some of the constituents indexed

in Tables 1 and 2, mainly a few carbon steels, could

submit to a diminish in ductility whilst used at low temperatures to such an volume as to be unable to securely

resist surprise loading, unexpected ameliorations of rigidity, or prime

rigidity awareness. Some codes or restrictions may additionally

require impact testing for programs even wherein temperatures are top than −29°C (−20°F). When such

requirements practice, it is the duty of the person

to make certain those requisites are communicated to the

manufacturer previous to the time of acquire.

2.6 System Pressure Testing

Flanged joints is likely to be subjected to gadget stress

checks at a stress of 1.five occasions the 38°C (one hundred°F) score

rounded off to the next greater 1 bar (25 psi) increment.

Testing at any greater rigidity is the obligation of

the user, deliberating the necessities of the

ideal code or law.

2.7 Welding Neck Flanges

2.7.1 Maximum Bore Size. Ratings for welding neck

flanges blanketed by this Standard are depending upon their

hubs on the welding conclusion having a thickness not less than equal

to that calculated for pipe having a 276 MPa (forty,000 psi)

special minimum yield energy. In order to assure

enough flange hub thickness for flange sizes NPS 26

and bigger, the bore of a welding neck flange, dimension

B as shown in Figs. 1 and a pair of, shall no longer exceed Bmax observed as follows: in which

A p tabulated hub diameter, birth of chamfer as indexed within the dimensional tables

Bmax p most permissible diameter for the bore

of a welding neck flange

The resultant gadgets for diameter Bmax are the same as

those entered for diameter A.

2.7.2 Components of Unequal Strength. The tabulated scores for welding neck flanges are autonomous

of aspects of unequal potential or unequal wall

thickness to which they can be attached. For all attachments, the pressure rating of the flange shall not be

surpassed.

2.7.3 Attachment Welds. Attachment welds have to

be made Check out this site according with the suited code or regulation. See para. 6.four and Fig. three for weld give up dimensional

necessities.

2.8 Multiple Material Grades

Materials for flanges might also meet the requisites of

a couple of specification or the standards of greater

than one grade of a specification listed in Table 1. In

either case, the pressure–temperature ratings for any of

these specifications or grades could also be used offered that the cloth is marked according with para. 4.2.8.