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Engineering Fields - Piping Design Engineering - New Member

Join Date: Oct 2008
Location: Chennai, India
Posts: 15

Pressure Vessel - ASME Section VIII

05/24/2010 2:56 AM

Hi All,

What is Class 1 Pressure Vessel and Class 2 Pressure Vessel? Is there any difference between these two?

I am new to pressure vessel design area. I found the term like "Class 1 PV" and "Class 2 PV" while I was reading a report on pressure vessel design of Air Receiver Tank.

I tried to get it in ASME Section VIII, but I could not get clear picture how it is different.

Thanks,

Nayek

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Associate

Join Date: Feb 2008
Posts: 46
Good Answers: 3
#1

Re: Pressure Vessel - ASME Section VIII

05/24/2010 9:05 AM

Assuming you are referring to Division I & Division II... I offer the following: (Source ASME)

Also listed is the Reference material for each division. Costs about $US600.00 ea. New. But I am sure you can pick up some used publications along the way.

DIV I

This Division of Section VIII provides requirements applicable to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures exceeding 15 psig.

Such pressure vessels may be fired or unfired. Specific requirements apply to several classes of material used in pressure vessel construction, and also to fabrication methods such as welding, forging and brazing.

It contains mandatory and non mandatory appendices detailing supplementary design criteria, nondestructive examination and inspection acceptance standards. Rules pertaining to the use of the U, UM and UV Code symbol stamps are also included.

BPVC-VIII - 2007 BPVC Section VIII-Rules for Construction of Pressure Vessels Division 1

DIV II

This Division of Section VIII provides requirements applicable to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures exceeding 15 psig. Such vessels may be fired or unfired.

This pressure may be obtained from an external source or by the application of heat from a direct or indirect source, or any combination thereof.

These rules provide an alternative to the minimum requirements for pressure vessels under Division 1 rules. In comparison to Division 1, Division 2 requirements on materials, design, and nondestructive examination are more rigorous; however, higher design stress intensity values are permitted.

Division 2 rules cover only vessels to be installed in a fixed location for a specific service where operation and maintenance control is retained during the useful life of the vessel by the user who prepares or causes to be prepared the design specifications.

These rules may also apply to human occupancy pressure vessels typically in the diving industry. Rules pertaining to the use of the U2 and UV Code symbol stamps are also included.

BPVC-VIII-2 - 2007 BPVC Section VIII-Rules for Construction of Pressure Vessels Division 2-Alternative Rules

Div III

This Division of Section VIII provides requirements applicable to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures generally above 10,000 psi.

Such vessels may be fired or unfired. This pressure may be obtained from an external source, a process reaction, by the application of heat from a direct or indirect source, or any combination thereof.

Division 3 rules cover vessels intended for a specific service and installed in a fixed location or relocated from work site to work site between pressurizations.

The operation and maintenance control is retained during the useful life of the vessel by the user who prepares or causes to be prepared the design specifications.

Division 3 does not establish maximum pressure limits for either Section VIII, Divisions 1 or 2, nor minimum pressure limits for this Division. Rules pertaining to the use of the UV3 Code symbol stamps are also included.

BPVC-VIII-3 - 2007 BPVC Section VIII-Rules for Construction of Pressure Vessels Division 3-Alternative Rules High Pressure Vessels

"Source: ASME"

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Anonymous Poster
#2
In reply to #1

Re: Pressure Vessel - ASME Section VIII

05/27/2010 11:39 AM

Thanks for your reply.

some more points have been noted in that design report, saying that

if the capacity of pressure vessel (in terms of bar.litres) exceeds 40000 bar.litres then pressure vessel come into class 2 category. If the capacity is within 40000 bar.litres then it is in class 1 category.

I dont see any such kind of notation in ASME Section VIII Code. Is there any other code which refer this kind of rules?

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Participant

Join Date: Dec 2010
Location: hubli karnataka india
Posts: 3
#3
In reply to #1

Re: Pressure Vessel - ASME Section VIII

03/14/2011 10:36 AM

HI,

can anyone let me know where can i find the thickness of outershell of a vacuum brazing furnace, details of thermocouples to be used, dimensions for flanges , vacuum port, water port, water jacket, front door mechanism, rear door mechanism and mounting legs all as per the Asme pressure vessel code section VIII, Div.1.

Its really very urgent, plz help me out.

Thank you

__________________
Rahul singh
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Anonymous Poster #1
#4

Re: Pressure Vessel - ASME Section VIII

05/09/2012 6:38 AM

"Unfired" Pressure Vessel Rules Alternative Rules Alternative Rules for High Pressure

Published

< 1940 1968 1997

Pressure Limits

Normally up to 3000 psig No limits either way, usually 600+ psig No limit; Normally from 10,000 psig

Organization

General, Construction Type & Material

U, UG, UW, UF, UB, UCS, UNF, UCI,

UCL, UCD, UHT, ULT

General, Material, Design, Fabrication

and others

AG, AM, AD, AF, AR, AI, AT, AS

Similar to Division 2

KG, KM, KD, KF, KR, KE, KT, KS

Design Factor

Design Factor 3.5 on tensile (4* used

previously) and other yield and

temperature considerations

Design Factor of 3 on tensile

(lower factor under reviewed) and other

yield and temperature considerations

Yield based with reduction factor for

yield to tensile ratio less than 0.7

Design Rules

Membrane - Maximum stress

Generally Elastic analysis

Very detailed design rules with Quality

(joint efficiency) Factors. Little stress

alaysis required; pure membrane

without consideration of discontinuities

controlling stress concentration to a

safety factor of 3.5 or higher

Shell of Revolution - Max. shear stress

Generally Elastic analysis

Membrane + Bending. Fairly detailed

design rules. In addition to the design

rules, discontinuities, fatigue and other

stress analysis considerations may be

required unless exempted and guidance

provided for in Appendix 4, 5 and 6

Maximum shear stress

Elastic/Plastic Analyses and more.

Some design rules provided; Fatigue

analysis required; Fracture mechanics

evaluation required unless proven leakbefore-

burst, Residual stresses become

significant and maybe positive factors

(e.g. autofrettage)

Experimental Stress

Analysis

Normally not required Introduced and may be required

Experimental design verification but may

be exempted

Material and Impact

Testing

Few restrictions on materials; Impact

required unless exempted; extensive

exemptions under UG-20, UCS 66/67

More restrictions on materials; impact

required in general with similar rules as

Division 1

Even more restrictive than Division 2

with different requirements.Fracture

toughness testing requirement for

fracture mechanics evaluation

Crack tip opening displacement (CTOD)

testing and establishment of KIc and/or

JIc values

NDE Requirements

NDE requirements may be exempted

through increased design factor

More stringent NDE requirements;

extensive use of RT as well as UT, MT and

PT.

Even more restrictive than Division 2;

UT used for all butt welds, RT otherwise,

extensive use of PT and MT

Welding and

fabrication

Different types with butt welds and

others

Extensive use/requirement of butt welds

and full penetration welds including nonpressure

attachment welds

Butt Welds and extensive use of other

construction methods such as threaded,

layered, wire-wound, interlocking stripwound

and others

User

User or designated agent to provide

specifications (see U-2(a))

User's Design Specification with detailed

design requirements (see AG-301.1)

include AD 160 for fatigue evaluation

User's Design Specification with more

specific details (see KG-310) including

contained fluid data, etc with useful

operation life expected and others.

Designer defined

Manufacturer

Manufacturer to declare compliance in

data report

Manufacturer's Design Report certifying

design specification and code compliance

in addition to data report

Same as Division 2

Professional

Engineer

Certification

Normally not required

Professional Engineers' Certification of

User's Design Specification as well as

Manufacturer's Design Report

Professional Engineer shall be experienced

in pressure vessel design

Same as Division 2 but the Professional

Engineer shall be experienced in high

pressure vessel design and shall not sign

for both User and Manufacturer

Safety Relief Valve

UV Stamp UV Stamp UV3 Stamp

Code Stamp and

Marking

U Stamp with Addition markings

including W, P, B, RES; L, UB, DF; RT,

HT

U2 Stamp with Additional marking

including HT

U3 Stamp with additional marking

denoting construction type; HT, PS, WL,

M, F, W, UQT, WW, SW

Hydrostatic Test

1.3 (Was 1.5 before the use of the 3.5

Design Factor in the 1999 Addenda)

1.25

1.25 (may be exempted for

autofrettaged vessels)

* In 1998, Code Cases 2278 and 2290 for ASME Section VIII Division 1 allowed for alternative maximum allowable design stresses based on a

a factor of 3.5 under certain provisions instead of a factor of 4 used by the Code. These code cases were incorporated into the Code in 1999.

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