Basics of Welding
ASME Sec VIII Div 1 Basics nrs (Rev.5 12 Mar 2010)
Basics of ASME Section VIII Division 1Pressure Vessels
Structure & Usage of
The Code Book
For
BEGINNERSThis guide is exclusively prepared for training
purpose. Relevant specifications, codes & special requirements
of specific project are to be referred for more detailed
information during construction. Examples provided are only for the
purpose of illustration.The objective is to be familiar with Basic
/ Fundamental concepts of the code.N.Rajasekaran (RAJ)
+971-50-6682960NeedEarly BoilerRoom Heater
ResultExplosionsDeath & Injuries
Corrective actionCommittee
ASME sponsorASME Code
Definitions:
SpecifyTo State or Describe something clearly and exactly.
Pressure VesselU-1(a)(2) For the scope of this Division,
pressure vessels are containers for the containment of pressure,
either internal or external. 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.
ConstructionAn all inclusive term comprising materials, design,
fabrication, examination, inspection, testing, certification and
pressure relief.
Mandatorydescribes something which must be done, or which is
demanded by law
A S M EAmerican Society of Mechanical EngineersCode Books: New
issuance every 3 Years
Edition 2007: White pages (loose-leaf format)Addenda 2008:
Pink Pages (replacement)Addenda 2009:
Blue Pages (replacement)Edition 2010: White pages ..and so
onContents:(1)Mandatory requirements, (2)Specific prohibitions
(2)Non-mandatory guidance Interpretations:
ASMEs written replies to inquiries concerning interpretation of
technical aspects of the Code. Issued semi annually (July and Dec)
as separate document.CODE CASES:Proposed additions and revisions to
the Code.
(to clarify the intent of existing requirements)orTo provide
rules not covered by existing Code. .The ASME Code BooksSec IPower
Boilers
Sec IIPart AMaterials: FerrousRef
Part BMaterials: Non FerrousRef
Part CMaterials: Filler & ElectrodesRef
Part DMaterial Properties (US ) or (Metric)Ref
Sec IIIRules for Construction of Nuclear Facility Components
Sec IVHeating Boilers
Sec VNondestructive ExaminationRef
Sec VICare and Operation of Heating Boilers
Sec VIICare of Power Boilers
Sec VIIIDiv 1Pressure Vessels
Div 2Alternative Rules - Pressure Vessels
Div 3Alternative Rules High Pressure Vessels
Sec IXWelding and Brazing QualificationsRef
Sec XFiber-Reinforced Plastic Pressure Vessels
Sec XIIn-service Inspection of Nuclear Power Plant
Components
Sec XIIConstruction and Continued Service of Transport Tanks
The Sec VIII Div 1 Code BookForeword Statement of Policy
PersonnelSummary of ChangesIntroduction - U
Mandatory Appendix Arabic NumeralsNon Mandatory Appendix
Alphabets
S.I Units
Index
Total Pages 40+675 = 715 (incl. front back cover)
Edition 2007
Unfired Vessel:UGeneral :
UGWelding :
UWCarbon Steel: UCS..and so onTitle
0mm4 mm7 mm12 mm15 mmSCOPE
U-1
U-1(a)
U-1(a)(1)
(a)
(1)
Numeric-(Alphabetic)-(Numeric)
(Alphabetic)
(Numeric)
The Code does not address all aspects of these activities and
those aspects which are not specifically addressed should not be
considered prohibited. The Code is not a handbook and cannot
replace education, experience, and the use of engineering judgment.
The phrase engineering judgment refers to technical judgments made
by knowledgeable designers experienced in the application of the
Code. Engineering judgments must be consistent with Code philosophy
and such judgments must never be used to overrule mandatory
requirements or specific prohibitions of the Code.The Code does not
fully address tolerances. When dimensions, sizes, or other
parameters are not specified with tolerances, the values of these
parameters are considered nominal and allowable tolerances or local
variances may be considered acceptable when based on engineering
judgment and standard practices as determined by the designer.
Vessel Scope by application: U-1(c)(2)Vessels not included
Listed U-1(c)(2) : (a) Thro (j)
Pressure below 3000 psi (in General)Vessel scope by geometry:
U-1(e)First girth weld (Circumferential joint)-by weldingFirst
threaded joint for screwed connection
Face of First Flange by bolting
Including covers for Manholes
Code accepted Referenced editions : U-3
Units of measurement U-4 (Code case 2523 )Sub Section A
PART UG :
General Requirements
(Common for Sub section B and C)
MaterialsUG 4 - UG 15
Design
Openings
Stay
Ligament
Fabrication
Inspection & Tests
Marking & Reports
Pr Relief
Figures
Tables
Example: SA 516 Grade 70 (SA 516M Grade 485)
UTS
= 70,000 PSI
SMYS= 38,000 PSI
S (allowable stress used in design for Temperature upto 500F) =
20,000 PSI
[Page 16 of Sec II Part D U.S Customary]F.S
= 38 / 20
= 1.9
U-4:UNITS OF MEASUREMENTFor any single equation, all variables
shall be expressed in a single system of units. When separate
equations are provided for U.S. Customary and SI units, those
equations must be executed using variables in the units associated
with the specific equation.70,000 PSI
= 482.633 MPa
485 - 482.633= 2.367
2.367 MPa
= 343 PSI !!!
1 MPa = 145.0377 PSI
Therefore
Do not mix two system of units in calculations. Sec II Part D (
The stress values) is issued in two versions
U.S Customary & Matric/S.IBasic approach of design
axial stress, a, sometimes called the longitudinal stress
tangential stress, t, also referred to as the hoop or
circumferential stress
radial stress, r . . . all of which are taken to be positive
tensile.
Cylinders are usually considered to be either thick - in which
stress concentration due to relative curvature is significant - or
thin in which stress concentration is negligible. Other differences
are : Thin Thick
Limiting proportions (approx) Di/t > 20 Di/t < 25
Analytic treatment simple approximation accurate
Statically determinate yes no
Stress state membrane - ie. biaxial triaxial
Stress - radial, r zero varies with radius
- tangential, t uniform varies with radius
- axial, a uniform uniform
The dividing line between thin and thick - is not hard and
fast.c = p Di / 2 t (Circumferential Hoop stress acting on Long
seam weld )
l = p Di / 4 t (Longitudinal stress acting on cir seam weld)
Conclusion: Cir seam weld is TWICE stronger than Long seam weld
when subjected to pressure.Therefore
Long seams are Category A : Cir seams are Category B
Basic Formula : c = p Di / 2 t; therefore t = p Ri / cCode
Formula:t = (p Ri )/ (SE-0.6p) : c = S = allowable stress
pressure= 250 PSI (p)
Radius (int)= 32 inchStress allowable = 20,000 PSI (SA 516 Gr
70)Basic FormulaCode Formula
t= 0.4 (10.16 mm)t= 0.403 (10.24 mm) if FULL RT (E=1.0)t= 0.475
(12.06 mm) if SPOT RT (E=0.85)t= 0.578 (14.67 mm) if NO RT
(E=0.7)
UG-32:FORMED HEADS, AND SECTIONS, PRESSURE ON CONCAVE SIDE
All formed heads concave to pressure and intended for butt
welded attachment need not have an integral skirt when the
thickness of the head is equal to or less than the thickness of the
shell. When a skirt is provided, its thickness shall be at least
that required for a seamless shell of the same inside diameter.Flat
spot on head max allowable diameter
UG-32 (o) ( UG-34 Formula (1), C=0.25
UG-37: REINFORCEMENT REQUIRED FOR OPENINGS IN SHELLS AND FORMED
HEADS
UG-80:PERMISSIBLE OUT-OF-ROUNDNESS OF CYLINDRICAL, CONICAL, AND
SPHERICAL SHELLS(Internal pressure)
UG-93:INSPECTION OF MATERIALS(a) Except as otherwise provided in
UG-4(b), UG-10, UG-11, or UG-15, requirements for acceptance of
materials furnished by the material manufacturer or material
supplier in complete compliance with a material specification of
Section II shall be as follows.
(1) For plates,2 the vessel Manufacturer shall obtain the
material test report or certificate of compliance as provided for
in the material specification and the Inspector shall examine the
Material Test Report or certificate of compliance and shall
determine that it represents the material and meets the
requirements of the material specification.
(2) For all other product forms, the material shall be accepted
as complying with the material specification if the material
specification provides for the marking of each piece with the
specification designation, including the grade, type, and class if
applicable, and each piece is so marked.UG-99:STANDARD HYDROSTATIC
TEST(g) Following the application of the hydrostatic test pressure,
an inspection shall be made of all joints and connections. This
inspection shall be made at a pressure not less than the test
pressure divided by 1.3. Except for leakage that might occur at
temporary test closures for those openings intended for welded
connections, leakage is not allowed at the time of the required
visual inspection. Leakage from temporary seals shall be directed
away so as to avoid masking leaks from other joints.Static head of
water : 0.433 psi for every feet of height.
UG-102:TEST GAGES(b) Dial indicating pressure gages used in
testing shall be graduated over a range of about double the
intended maximum test pressure, but in no case shall the range be
less than 112 nor more than 4 times that pressure. Digital reading
pressure gages having a wider range of pressure may be used
provided the readings give the same or greater degree of accuracy
as obtained with dial pressure gages.UG-116:REQUIRED MARKINGRT 1
when all pressure-retaining butt welds, other than Category B and C
butt welds associated with nozzles and communicating chambers that
neither exceed NPS 10 (DN 250) nor 118 in. (29 mm) wall thickness
[except as required by UHT-57(a)], satisfy the full radiography
requirements of UW-11(a) for their full length; full radiography of
the above exempted Category B and C butt welds, if performed, may
be recorded on the Manufacturers Data Report; or
RT 2 when the complete vessel satisfies the requirements of
UW-11(a)(5) and when the spot radiography requirements of
UW-11(a)(5)(b) have been applied; or RT 3 when the complete vessel
satisfies the spot radiography requirements of UW-11(b); orRT 4
when only part of the complete vessel has satisfied the
radiographic requirements of UW-11(a) or where none of the markings
RT 1, RT 2, or RT 3 are applicable.
Sub Section B
PART UW :
Welding Requirements
UW-2:SERVICE RESTRICTIONS(a) When vessels are to contain lethal1
substances, either liquid or gaseous, all butt welded joints shall
be fully radiographed, except.UW-3:WELDED JOINT CATEGORY
UW-11:RADIOGRAPHIC AND ULTRASONIC EXAMINATION(a) Full
Radiography
(b) Spot Radiography.
(c) No RadiographyUW-12:JOINT EFFICIENCIES
Table UW-12UW-33:ALIGNMENT TOLERANCE Joint Categories
Thickness (mm)AB, C, & D
Up to 13, incl. t t
Over 13 to 19, incl.3 mm t
Over 19 to 38, incl.3 mm5 mm
Over 38 to 51, incl.3 mm t
Over 51Lesser of 116t or 10mmLesser of t or 19 mm
UW-51:RADIOGRAPHIC EXAMINATION OF WELDED JOINTS (1) any
indication characterized as a crack or zone of incomplete fusion or
penetration;
(2) any other elongated indication on the radiograph which has
length greater than:
(a) 14 in. (6 mm) for t up to 34 in. (19 mm)
(b) 13t for t from 34 in. (19 mm) to 214 in. (57 mm)
(c) 34 in. (19 mm) for t over 214 in. (57 mm)
where
t =the thickness of the weld excluding any allowable
reinforcement. For a butt weld joining two members having different
thicknesses at the weld, t is the thinner of these two thicknesses.
If a full penetration weld includes a fillet weld, the thickness of
the throat of the fillet shall be included in t.
(3) any group of aligned indications that have an aggregate
length greater than t in a length of 12t, except when the distance
between the successive imperfections exceeds 6L where L is the
length of the longest imperfection in the group;
(4) rounded indications in excess of that specified by the
acceptance standards given in Appendix 4.
UW-52:SPOT EXAMINATION OF WELDED JOINTS 1 spot in 50 feet RT
(1) any indication characterized as a crack or zone of
incomplete fusion or penetration;(2) Elongated > 2/3 t
(thinner); l >t in 6t ..; 19 max, 6 on any t..
(3) Rounded indications are not a factor in the acceptability of
welds not required to be fully radiographed.
Rectify original repair
All weld is accepted
Remove entire weld and reweld
Or
100% RT and rectify the repairs
Sub Section C
PART UCS :
Material Requirements
UCS-6:STEEL PLATES
(b) Steel plates conforming to SA-36, SA/CSA-G40.21 38W, and
SA-283 Grades A, B, C, and D may be used for pressure parts in
pressure vessels provided all of the following requirements are
met:
(1) The vessels are not used to contain lethal substances,
either liquid or gaseous.
(2) The material is not used in the construction of unfired
steam boilers [see U-1(g)].
(3) With the exception of flanges, flat bolted covers, and
stiffening rings, the thickness of plates on which strength welding
is applied does not exceed 58 in. (16 mm).UCS-56:REQUIREMENTS FOR
POSTWELD HEAT TREATMENTTABLE UCS-56
POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY
STEELSMaterialNormal Holding Temperature, F (C), MinimumMinimum
Holding Time at Normal Temperature
for Nominal Thickness [See UW-40(f)]
Up to 2 in.
(50 mm)Over 2 in. to 5 in.
(50 mm to 125 mm)Over 5 in.
(125 mm)
P-No. 1
Gr. Nos. 1, 2, 31,100 (595)1 hr/in. (25 mm), 15 min minimum2 hr
plus 15 min for each additional inch (25 mm) over 2 in. (50 mm)2 hr
plus 15 min for each additional inch (25 mm) over 2 in. (50 mm)
Gr. No. 4= not applicableNoneNoneNone
NOTES:
(1) When it is impractical to postweld heat treat at the
temperature specified in this Table, it is permissible to carry out
the postweld heat treatment at lower temperatures for longer
periods of time in accordance with Table UCS-56.1.
(2) Postweld heat treatment is mandatory under the following
conditions:
(a) for welded joints over 1 in. (38 mm) nominal thickness;
(b) for welded joints over 114 in. (32 mm) nominal thickness
through 112 in. (38 mm) nominal thickness unless preheat is applied
at a minimum temperature of 200F (95C) during welding;
(c) for welded joints of all thicknesses if required by UW-2,
except postweld heat treatment is not mandatory under the
conditions specified below:
(1) for groove welds not over in. (13 mm) size and fillet welds
with a throat not over in. (13 mm) that attach nozzle connections
that have a finished inside diameter not greater than 2 in. (50
mm), provided the connections do not form ligaments that require an
increase in shell or head thickness, and preheat to a minimum
temperature of 200F (95C) is applied;
(2) for groove welds not over 12 in. (13 mm) in size or fillet
welds with a throat thickness of 12 in. (13 mm) or less that attach
tubes to a tubesheet when the tube diameter does not exceed 2 in.
(50 mm). A preheat of 200F (95C) minimum must be applied when the
carbon content of the tubesheet exceeds 0.22%.
(3) for groove welds not over 12 in. (13 mm) in size or fillet
welds with a throat thickness of 12 in. (13 mm) or less used for
attaching nonpressure parts to pressure parts provided preheat to a
minimum temperature of 200F (95C) is applied when the thickness of
the pressure part exceeds 114 in. (32 mm);
(4) for studs welded to pressure parts provided preheat to a
minimum temperature of 200F (95C) is applied when the thickness of
the pressure part exceeds 114 in. (32 mm);
(5) for corrosion resistant weld metal overlay cladding or for
welds attaching corrosion resistant applied lining (see UCL-34)
provided preheat to a minimum temperature of 200F (95C) is
maintained during application of the first layer when the thickness
of the pressure part exceeds 114 in. (32 mm).
UCS-57:RADIOGRAPHIC EXAMINATIONTABLE UCS-57
THICKNESS ABOVE WHICH FULL RADIOGRAPHIC EXAMINATION OF BUTT
WELDED JOINTS IS MANDATORYP-No. & Group No. Classification of
MaterialNominal Thickness Above Which
Butt Welded Joints Shall Be Fully Radiographed, in. (mm)
1 Gr. 1, 2, 3114 (32)
3 Gr. 1, 2, 334 (19)
4 Gr. 1, 258 (16)
5A Gr. 1, 2 0 (0)
5B Gr. 1, 20 (0)
5C Gr. 10 (0)
.and so onLOW TEMPERATURE OPERATIONUCS-66:MATERIALSFIG. UCS-66.2
DIAGRAM OF UCS-66 RULES FOR DETERMINING LOWEST MINIMUM DESIGN METAL
TEMPERATURE (MDMT) WITHOUT IMPACT TESTING
FIG. UCS-66 IMPACT TEST EXEMPTION CURVES (CONTD)
NOTES:
(1) Curve A applies to:
(a) all carbon and all low alloy steel plates, structural
shapes, and bars not listed in Curves B, C, and D below;
(b) SA-216 Grades WCB and WCC if normalized and tempered or
water-quenched and tempered; SA-217 Grade WC6 if normalized and
tempered or water-quenched and tempered.
(2) Curve B applies to:
(a) SA-216 Grade WCA if normalized and tempered or
water-quenched and tempered SA-216 Grades WCB and WCC for
thicknesses not exceeding 2 in. (50 mm), if produced to fine grain
practice and water-quenched and tempered
SA-217 Grade WC9 if normalized and tempered
SA-285 Grades A and B
SA-414 Grade A
SA-515 Grade 60
SA-516 Grades 65 and 70 if not normalized
SA-612 if not normalized
SA-662 Grade B if not normalized
SA/EN 10028-2 P295GH as-rolled;(b) except for cast steels, all
materials of Curve A if produced to fine grain practice and
normalized which are not listed in Curves C and D below;
(c) all pipe, fittings, forgings and tubing not listed for
Curves C and D below;
(d) parts permitted under UG-11 shall be included in Curve B
even when fabricated from plate that otherwise would be assigned to
a different curve.
(3) Curve C applies to:
(a) SA-182 Grades 21 and 22 if normalized and tempered
SA-302 Grades C and D
SA-336 F21 and F22 if normalized and tempered
SA-387 Grades 21 and 22 if normalized and tempered
SA-516 Grades 55 and 60 if not normalized
SA-533 Grades B and C
SA-662 Grade A;(b) all material of Curve B if produced to fine
grain practice and normalized and not listed for Curve D below.
(4) Curve D applies to:
SA-203
SA-508 Grade 1
SA-516 if normalized
SA-524 Classes 1 and 2
SA-537 Classes 1, 2, and 3
SA-612 if normalized
SA-662 if normalized
SA-738 Grade A
SA-738 Grade A with Cb and V deliberately added in accordance
with the provisions of the material specification, not colder than
20F (29C)
SA-738 Grade B not colder than 20F (29C)
SA/AS 1548 Grades 7-430, 7-460, and 7-490 if normalized
SA/EN 10028-2 P295GH if normalized [see Note (e)(3)]
SA/EN 10028-3 P275NH
UCS-68(c) If postweld heat treating is performed when it is not
otherwise a requirement of this Division, a 30F (17C) reduction in
impact testing exemption temperature may be given to the minimum
permissible temperature from Fig. UCS-66 for P-No. 1 materials. The
resulting exemption temperature may be colder than 55F
(48C).MANDATORY APPENDIX 8
METHODS FOR
LIQUID PENETRANT EXAMINATION (PT)8-3 EVALUATION OF
INDICATIONS
An indication of an imperfection may be larger than the
imperfection that causes it; however, the size of the indication is
the basis for acceptance evaluation. Only indications with major
dimensions greater than 116 in. (1.5 mm) shall be considered
relevant. (a) A linear indication is one having a length greater
than three times the width.
(b) A rounded indication is one of circular or elliptical shape
with the length equal to or less than three times the width.
(c) Any questionable or doubtful indications shall be reexamined
to determine whether or not they are relevant.
8-4 ACCEPTANCE STANDARDS
These acceptance standards shall apply unless other more
restrictive standards are specified for specific materials or
applications within this Division. All surfaces to be examined
shall be free of:
(a) relevant linear indications;
(b) relevant rounded indications greater than 316 in. (5
mm);
(c) four or more relevant rounded indications in a line
separated by 116 in. (1.5 mm) or less (edge to edge).
Indication size
> 5.0 mmRelevant: Noted & Not Acceptable (Rejected /
Repair)
1.5 5.0 mmRelevant: Noted & Acceptable
< 1.5 mmIrrelevant: Acceptable
Code Interpretations
-----------------------------------------------------
Interpretation: VIII-1-01-02
Subject:Section VIII, Division 1 (1998 Edition, 1999 Addenda);
UG-99(g)Date Issued: September 8, 2000File: BC00-393Question: A
vessel is subjected to the hydro test under UG-99. During the test,
a leak is detected from the gasket seat of a permanent flanged
joint. In meeting the requirements of UG-99(g) in Section VIII,
Division 1, may the hydro test be accepted if the flanged joint and
the vessel as a whole are found to be completely tight after the
pressure is reduced to not less than the test pressure divided by
1.3?Reply: Yes.
-----------------------------------------------------
Interpretation: VIII-1-98-86
Subject: Section VIII, Division 1 (1998 Edition, 1998 Addenda);
UG-99(b) and (c)
Date Issued: October 25, 1999
File: BC99-346
Question: Do the requirements of UG-99(b) and (c) in Section
VIII, Division 1 preclude the use of a temperature recorder for the
test medium during the performance of the hydrostatic test?
Reply: No.
-----------------------------------------------------
Interpretation: VIII-1-98-110Subject: Section VIII, Division 1
(1998 Edition, 1999 Addenda); UW-40(c) and UCS-56(d)(3)
Date Issued: March 22, 2000
File: BC00-082
Question: In complying with the requirements of UW-40(c) and
UCS-56(d)(3) in Section VIII, Division 1, is it necessary to have
thermocouples attached to both the inside and outside surfaces of a
vessel during postweld heat treatment?
Reply: No.
-----------------------------------------------------
Interpretation: VIII-1-01-85Subject: Section VIII, Division 1
(1998 Edition, 2000 Addenda); UW-31(d) and UW-33(a)
Date Issued: September 24, 2001
File: BC01-325
Question(1):In meeting the requirements of Section VIII,
Division 1, may the over thickness tolerance, as permitted by the
plate specification, be excluded from the maximum offset in
evaluating the alignment tolerances of UW-31(d) and UW-33?
Reply (1): No.
Question(2):May the maximum offset per UW-33(a) be increased by
an amount equal to the difference between the actual thickness and
the required thickness?
Reply (2): No.
-----------------------------------------------------
Information
Basics: the simplest and most important factsConcept:Principle
or idea
Philosophy:use of principles that govern and influence
judgment
Sub section C
Classes of Materials
Sub section B
Method of Fabrication
Sub section A
General Requirements
R
R
R
A
A
R
R
A
R
Metric
485 MPa
(70 KSI)
UTS
70,000 PSI
(70 KSI)
UTS
Fill Here !
Excercise
Establish nominal thickness [Note (1)] of welded parts, non
welded parts, and attachments under consideration both before and
after corrosion allowance is deducted (tn and tn c, respectively),
and other pertinent data applicable to the nominal thickness such
as:
All applicable loadings [Note (2)] and coincident minimum design
metal temperature (MDMT)
Materials of construction
E= joint efficiency [Note (3)]
tn= nominal non-corroded thickness [Note (1)], in. (mm)
tr= required thickness in corroded condition for all applicable
loadings [Note (2)], based on the applicable joint efficiency [Note
(3)], in. (mm)
Applicable curve(s) of Fig. UCS-66
c= corrosion allowance, in. (mm)
Step 1
Select MDMT from Fig. UCS-66 [Note (4)] for each nominal
non-corroded governing thickness [Note (5)].
Using Ratio from Step 3 to enter ordinate
of Fig. UCS-66.1, determine reduction in Step 2 MDMT [Note
(9)].
Step 6
Step 5
Step 4
Step 3
Step 2
Determine Ratio: (trE*) /( tn c)
[Notes (3), (6), (7), and (8)]
Determine adjusted MDMT for governing
thickness under consideration.
Repeat for all governing thicknesses [Note (5)] and take warmest
value as the lowest allowable MDMT to be marked on nameplate for
the zone under consideration [Note (10)]. See UG-116.
See UG-99(h) for coldest recommended metal temperature during
hydrostatic test [Note (6)].
See UG-100(c) for coldest metal temperature permitted during
pneumatic test [Note (6)].
Required
Optional
Refer UG-20(f) also
Page 27 of 27
