ASME Section viii Div-1 Traing ppt..pdf

ASME VIII Div.1- Charlie Chong/ Fion Zhang/ He Jungang / Li Xueliang
ASME VIII Div.1
API510 Training for 2013 June.

Speaker: Fion Zhang
2013/April/15

Applicable sections;
 UG: the G denotes general requirements.
 UW: the W denotes welding.
 UCS: the CS denotes carbon steel.
 UHT: the HT denotes heat treatment.
 Appendix 1: supplementary design formulae.
 Appendix 3: definitions.

SUBSECTION A
GENERAL REQUIREMENTS

PART UG
GENERAL REQUIREMENTS FOR ALL
METHODS OF CONSTRUCTION AND ALL
MATERIALS

Vessel design
features

The main ASME VIII design topics required included in the API 510
syllabus are:
 Internal pressure in shells and heads (clauses UG-27 and UG-32)
 External pressure on shells (clause UG-28)
 Nozzle compensation (mainly figure UG-37.1)
 Nozzle weld sizing (mainly figure UW-16)

About rounding answers. In the ASME Code
and for the exam you must round DOWN for
pressure allowed. Even if our solution had
been 1079.999 we cannot round to 1080, we
still round down to 1079 psi. This is the
conservative approach taken by the Codes in
general and of course is different for the
normal rules of rounding.
When rounding thickness required we must
round UP. The most conservative thing to do.
So our example below would round to .230”.
Even it had been .2291 we would still round
up to .230”.

UG-20 DESIGN TEMPERATURE
UG-20

ASME VIII Div.1- Charlie Chong/ Fion Zhang/ He Jungang / Li Xueliang UG-20
UG-20(f) lists an exemption from impact testing for materials that
meet “All” of the following requirements.
1. Material is limited to P-No.1 Gr. No.1 or 2 and the thicknesses
don't exceed the following:
(a) 1/2 in. for materials listed in Curve A of Fig. UCS-66;
(b) 1 in for materials from Curve B, C or D of Fig. UCS-66;
2. The completed vessel shall be hydrostatically tested
3. Design temperature is no warmer than 650°F or colder than -
20°F.
4. The thermal or mechanical shock loadings are not controlling
design.
5. Cyclical loading is not a controlling design requirement.

1. Material is limited to P-No.1
Gr. No.1 or 2 and the
thicknesses don't exceed the
following:
(a) 1/2 in. for materials listed in
Curve A of Fig. UCS-66;
(b) 1 in for materials from Curve
B, C or D of Fig. UCS-66;
All of the conditions of UG-20(f)
must be met to take this
exemption from impact testing.

UG-27 THICKNESS OF SHELLS UNDER
INTERNAL PRESSURE.
UG-27

c) Cylindrical Shells. The minimum thickness or maximum allowable working
pressure of cylindrical shells shall be the greater thickness or lesser pressure as given
by (1) or (2) below.
(1) Circumferential Stress (Longitudinal Joints).
When the thickness does not exceed one-half of the inside radius, or P does not exceed
0.385SE, the following formulas shall apply:
(2) Longitudinal Stress (Circumferential Joints). When the thickness does not exceed
one-half of the inside radius, or P does not exceed 1.25SE, the following formulas shall
apply:
UG-27

Shell calculations: internal pressure
Shell calculations are fairly straightforward and are set out in UG-27. Figure below
shows the two main stresses existing in a thin-walled vessel shell.
Hoop (circumferential) stress
This is the stress trying to split the vessel open along its length. Confusingly, this acts on
the longitudinal weld seam (if there is one). For the purpose of the API 510 exam this is
the governing stress in a shell cylinder.
UG-27

The relevant UG-27 equations are:
(used when you want to find t) or, rearranging the equation to find P when t is already
known:
Where:
• P = maximum design pressure (or MAWP).
• t = minimum required thickness to resist the stress.
• S = allowable stress of the material.
• E = joint efficiency.
• Ri = the internal radius of the vessel.
UG-27

• Remarks:
• S = allowable stress of the material. This is read from ASME II part D tables or,
more commonly, given in the exam question (it has to be as ASME II part D is
not in the syllabus).
• E = joint efficiency. This is a factor (between 0.65 and 1) used to allow for the
fact that a welded joint may be weaker than the parent material. It is either read
off tables (see UW-11 and UW-12 later) or given in the exam question. You can
think of E as a safety factor if you wish.
• Ri = the internal radius of the vessel. Unlike some other design codes ASME
VIII Div.I prefers to use the internal radius as its reference dimension, perhaps
because it is easier to measure.
UG-27

ASME
VIII
Div.1-
Charlie
Chong/
Fion
Zhang/
He
Jungang
/
Li
Xueliang
Figure 9.4 Vessel stresses
UG-27

A key feature of Ri is that it is the radius in the corroded conditions (i.e.
that anticipated at the next scheduled inspection). Don’t get confused by
this – it is just worked out in this way. If a vessel has a current Ri of 10 in
and has a corrosion rate (internal) of 0.1 in./years, with the next scheduled
inspection in five years, then:
Current Ri = 10 in.
Ri in 5 years = 10 in. + (5 x 0.1 in) = 10.5 in corroded condition.
Hence 10.5 in. is the Ri dimension to use in the UG-27 equation.
UG-27

 The thickness must not exceed one-half of the inside radius, i.e.
it is not a thick cylinder.
 The pressure must not exceed 0.385SE, i.e. not be high
pressure. In practice this is more than about 4000 psi for most
carbon steel vessels.
UG-27

 The pressure must not exceed 0.385SE, i.e. not be high pressure. In
practice this is more than about 4000 psi for most carbon steel vessels.
Example: for SA-515/Gr. 60 at 700°F where S = 14,400 psi. P must not exceed
5544 psi.

Shell calculation example
The following information is given in the question.
Ri = inside radius of 30 in .
P = pressure of 250 psi (MAWP).
E = 0.85 (type 1 butt weld with spot examination as per UW-12).
S = 15 800 psi.
What minimum shell thickness is necessary to resist the internal MAWP?
Using thickness (t) = PR/(SE–0.6P) from UG-27
Thickness = 250x30 / [15800x0.85 – (0.6x250)]
t = 0.565 in ANSWER
UG-27

Shell calculation example
The following information is given in the question.
Ri = inside radius of 30 in.
t = 0.625 in.
E = 0.85 (type 1 butt weld with spot examination as per UW-12).
S = 15 800 psi.
What is the MAWP?
Using pressure (P) = SEt/(R + 0.6t) from UG-27
Pressure (P) = 15 800 x 0.85x 0.625 /
[30 + (0.6 x 0.625)], MAWP = 276 psi ANSWER.
UG-27

DESIGN INFORMATION
• Design Pressure = 250 psig.
• Design Temperature = 700°F.
• Shell and Head Material is SA-515 Gr. 60.
• Corrosion Allowance = 0.125 in.
• Both Heads are Seamless
• Shell and Cone Welds are Double welded.
• Heads are spun and press without welding.
• Welded and will be Spot Radiographed
• The Vessel is in All Vapor Service
• Cylinder Dimensions Shown are Inside
Diameters

ASME VIII Div.1- Charlie Chong/ Fion Zhang/ He Jungang / Li Xueliang UW-12
Summary Maximum Weld Joint Efficiency: Joint Type 1~6

The allowable stress is given in ASME II, as it is not part of API510 examination, the
following should be given: S = 14,400 psi for SA-515/Gr. 60 at 700°F

If corrosion allowance is specified: (usually not in API510 exam)
Rcal for 6’ = 36.125”
Rcal for 4’ =24.125”
The Rcal or Dcal used in
calculation shall be the
vessel RDesign or DDesign plus
the corrosion allowance.
The required wall thickness
shall be pressure thickness +
corrosion allowance tp+c
c =
Corrosion
Allowance
R design= Designed
radius
R calculation =
R design + c,
Radius used
for calculation
tp =
thickness
required for
internal
pressure

Lower section
2:1 ellipsoidal
head
Lower section
6’ID shell
Middle section
conical
Top section
4’ID shell
Top
hemispherical
head
Section
1.0
0.85
0.85
0.85
1.0?
Required Thickness tp + c
Equation
E
P=250psig, S=14400psi, c=0.125in.
Dcal = 72 + 2 x 0.125 = 72.25 in.
Rcal = 24 + 0.125 = 24.125 in.
Rcal = 24 + 0.125 = 24.125 in.
Rcal = 36 + 0.125 = 36.125 in.

35
35
D = inside diameter of the head skirt; or inside
length of the major axis of an ellipsoidal head;
or inside diameter of a conical head at the point
under consideration, measured perpendicular to
the longitudinal axis.
Di = inside diameter of the conical portion of a
toriconical head at its point of tangency to the
knuckle, measured perpendicular to the axis of
the cone
= D − 2r (1 − cos α )
E = lowest efficiency of any joint in the head;
for hemispherical heads this includes head-
to-shell joint; for welded vessels, use the
efficiency specified in UW-12
L = inside spherical or crown radius. The
value of L for ellipsoidal heads shall be
obtained from Table UG-37.
P = internal design pressure (see UG-21)
r = inside knuckle radius
S = maximum allowable stress value in
tension as given in the tables referenced
in UG-23, except as limited in UG-24 and
(e) below.
t = minimum required thickness of head
after forming
ts = minimum specified thickness of head
after forming, in. (mm). ts shall be ≥ t
α = one-half of the included (apex)
angle of the cone at the centerline of the
head (see Fig. 1-4)
UG-32(a)

Lower section
2:1 ellipsoidal
head
Lower section
6’ID shell
Middle section
conical
Top section
4’ID shell
Top
hemispherical
head
Section
1.0
0.85
0.85
0.85
0.85
Required Thickness tp + c
Equation
E
P=250psig, S=14400psi, c=0.125in.
Dcal = 72 + 2 x 0.125 = 72.25 in.
Rcal = 24 + 0.125 = 24.125 in.
Rcal = 24 + 0.125 = 24.125 in.
Rcal = 36 + 0.125 = 36.125 in.

Exercise 2
Required Thickness for Internal Pressure
Determine the minimum required thickness for the cylindrical shell and
heads of the following pressure vessel:
· Inside Diameter = 10’ 6”
· Design Pressure = 650 psig
· Design Temperature = 750°F
· Shell & Head Material = SA-516 Grade 70
· Corrosion Allowance = 0.125”
· 2:1 Semi-Elliptical heads, seamless
· 100% radiography of cylindrical shell welds
· The vessel is in an all vapor service (i.e., no liquid loading)
---------------------------------------------------------------------------

Answers:
Inside diameter = 126 + 0.25 = 126.25 in. Ri= 63.125 in. S=14800psi,
E=1.
Calculations:
Shell:
tp = (650x63.125)/(14800-0.6x650) =2.848 in.
tshell = tp+c = 2.847+0.125 = 2.973 in.#
Head:
tp = (650x126.25)/(2x14800-0.2x650) = 2.785 in.
Thead = tp+c=2.785+0.125=2.910 in.#

Appendix 1 Supplementary Design Formulas
1-1 THICKNESS OF CYLINDRICAL AND SPHERICAL SHELLS
(a) The following formulas, in terms of the outside radius, are equivalent to and may
be used instead of those given in UG-27 (c) and (d).
(1) For cylindrical shells (circumferential stress),

Example: Given a cylindrical shell with the following variables, solve for the MAWP
of the cylinder using both formulas.
P = ? , t = 0.500“, S = 15,000 psi, E = 1.0, R = 18.0“ and Routside = 18.5"
Exercise 3

A cylindrical shell has been found to have a minimum thickness of .353". Its original
thickness was .375” with an original inside radius of 12.0”. S = 13,800 psi, E = .85
What is its present MAWP ?
R = 12.0" + (.375-.353) = 12.022 corroded inside radius
Ro= 12.0" + 0.375 (orig. t) =12.375” original outside radius
Exercise 4

You need to consider the hemispherical head joint to shell as category A, but
ellipsoidal and torispherical head joint to shell as category B;
Do you know why? Why ASME considered the stringent rule for pressure vessel RT
test in hemispherical head joint?
It is because this joint is more critical, because the thickness obtained from the
formula for hemispherical head approximately would be half of the shell thickness;
It means if the shell thickness is 1 inch, the hemispherical head thickness would be
0.5 inch.

44
Example: For the same pressure, stress and, dimension values will be used for all
heads. Let’s determine which type of head will be the thickest required and which
will be the thinnest allowed.
Given:
P = 100 psi
S = 17500 PSI
E = .85 for spot RT of hemispherical head joint to shell
E = 1.0 for seamless heads ( Ellipsoidal and Torispherical )
L = 48" for the inside spherical radius for the hemispherical head
L = 96" for the inside crown radius of the torispherical head
D = 96" inside diameter of the ellipsoidal
t = ? Required wall thickness, inches

45
t = (100x48)/(2x17500x0.85
t = (100x48)/(2x17500x0.85-
-0.2x100)
0.2x100)
t = 0.162
t = 0.162”
”
Hemispherical
Hemispherical
t = (0.885x100x96)/(17500x1
t = (0.885x100x96)/(17500x1-
-0.1x100)
0.1x100)
T= 0.486
T= 0.486”
”
Torispherical
Torispherical
t = (100x96) / (2x17500x1
t = (100x96) / (2x17500x1-
-0.2x100)
0.2x100)
t = 0.275
t = 0.275”
”
Ellipsoidal
Ellipsoidal
thickness
thickness
Equation
Equation
Head
Head

Spot radiography for
ellipsoidal and torispherical
heads (Cat. B). Full
radiography foe hemispherical
head (Cat. A).

UG-28 THICKNESS OF SHELLS AND TUBES
UNDER EXTERNAL PRESSURE.
UG-28

Overview.
The critical pressure that causes buckling is not a simple function of
the stress that is produced in the shell, as is true with tensile loads. An
allowable stress is not used to design pressure vessels that are subject
to elastic instability. Instead, the design is based on the prevention of
elastic collapse under the applied external pressure. This applied
external pressure is normally 15 psig for full vacuum conditions.
The maximum allowable external pressure can be increased by
welding circumferential stiffening rings (i.e., stiffeners) around the
vessel shell. The addition of stiffening reduces the effective buckling
length of the shell, and this length reduction increases the allowable
buckling pressure. These stiffener rings may be welded on either the
inside or the outside of the shell.
UG-28

Basic Data (example)
Temperature = 500°F
t = 0.530 in.
L = 120 in.
Do = 10 in.
1. Calculate Do/t
2. Calculate L/Do
Find A and B
using Chart Fig. G and applicable material chart in Subpart 3 of Section II, Part D.
As stated in the API 510 Body of Knowledge, these charts will be provided in the exam
body, IF an external calculation is given on the examination.
3. Calculate P

1. Use common chart and Find A
As stated in the API
510 Body of
Knowledge, these
charts will be
provided in the
exam body, IF an
external calculation
is given on the
examination.

2. Select applicable material chart and Find B
As stated in the API 510 Body of Knowledge, these charts will be
provided in the exam body, IF an external calculation is given on the examination.

3. Calculate P

UG-28, C(1)- Cylinders having Do /t values ≥ 10:
Example #1
The easiest way to understand the UG-28 calculations themselves is to look at this
worked example. Figure 9.14 shows the parameters for a vessel under external pressure
operating at 300oF:
. t = thickness of the shell = 0.25 in.
. L = distance between stiffeners = 90 in.
. Do = shell outside diameter = 180 in.
The first step is to calculate the values of the dimensional ratios (L/Do) and (Do/t):
L/Do = 90/180 = ½
Do/t = 180 / 0.25 = 720
UG-28

In a real design situation, these ratios would then be plotted on charts to give values of A
and B. In this example, the charts would give values of A = 0.000 15 and B = 2250
(remember that you will generally be given these in an exam question).
Pa = 4B/[3 (Do/t)] = 4x 2250/(3x 720) = 4.2 psi
Conclusion – the vessel is not suitable for full vacuum duty (-14.5 psi ).
Conclusion – the vessel is
not suitable for full vacuum
duty (-14.5 psi ).
Pa should be ≥14.5psi
UG-28

Example #1-2
Limited data for a vessel are given as:
Outside diameter Do = 60 in
Length between supports L = 15 feet
Factor A = 0.000 18, Factor B = 2500
These are all the data you have. How thick does the vessel wall have to be to be suitable
for use under full vacuum?
t = 3PaDo/(4B) = 3x14.5x60 / (4x2500) = 0.261in.
Select your answer:
(a) 1/8 in.
(b) ¼ in.
(c) 3/8 in.
(d) others.
UG-28

Example #2
Step 1 Assume a value for t and determine the ratios L/Do and Do /t.
Example: The cylinder has corroded to a wall thickness of 0.530”, its length is 120” and
the outside diameter is 10”. It operates at 500oF
So then;
Temp = 500oF
t = 0.530”
L = 120”
Do = 10”
Calculate;
Do/t = 10/.530 = 18.8 call it 19# (no need to be exact)
L/Do = 120/10 = 12#
UG-28

Example of Calculation using graphs
Normally values A & B are given without using the
ASME II graphs
UG-28

Step 2 Enter Fig. G in Subpart 3 of Section II, Part at the value of L/Do determined in
Step 1. we must go up the left side of the Fig. G until we reach the value of L/Do of 12.
•Using the chart we have the following;
Do/t = 19
L/Do = 12
UG-28

Step 3 Move horizontally to the line for the value Do /t determined in Step 1.... Which
in our case was 19, but we will round this to 20 since these problems are not meant to
be extremely precise. So now we have. From this point of intersection move ertically
downward to determine the value of factor A.
Do/t = 19
L/Do = 12
UG-28

Do/t
=
19,
L/Do
=
12
UG-28

Step 4 Enter the applicable material chart in Subpart 3 of Section II, Part D for the
material under consideration. Move vertically to an intersection with the
material/temperature line for the design temperature. Interpolation may be made
between lines for intermediate temperatures. To use the next figure we enter at the
bottom at the value Factor A = .0028 and then up to our temperature of 500oF.
UG-28

Do/t = 19
L/Do = 12
A=0.0028
UG-28

Example #3
Problem: A vessel is operating under an external pressure, the operating temperature is
500oF. The outside diameter of the vessel is 40 inches. Its length is 70 inches. The
vessel’s wall is 1.25 inches thick and is of SA-515-70 plate. Its specified min. yield is
38,000 psi. What is the maximum external pressure allowed?
Givens:
Temp = 500oF
t = 1.25 in.
L = 70 in.
D0 = 40 in.
Determine;
Do/t = 40/1.25 = 32 used equation c(1).
L/Do = 70/40 = 0.175.
Determine value “A”
UG-28

Step 4. Using our value of Factor A calculated in Step 3, enter the Factor B (CS-2)
chart on the bottom. Move vertically to the material temperature line given in the
stated problem (in our case 500oF).
A=0.0045
UG-28

Step 5 Then across to find the value of Factor B. We find that Factor B is
approximately 13000.
Step 6 Using this value of Factor B, calculate the value of the maximum
allowable external pressure Pa using the following formula:
UG-28

Example #3
Problem: A vessel is operating under an external pressure, the operating
temperature is 500° F. The outside diameter of the vessel is 40 inches.
Its length is 70 inches. The vessel’s wall is 1.25 inches thick and is of
SA-515-70 plate. Its specified min. yield is 38,000 psi. What is the
maximum external pressure allowed?
Givens:
Mtls = SA-515 Gr.70.
Temp = 500°F.
t = 1.25 inches.
L = 70 inches.
Do = 40 inches.
Do/t = 40/1.25 = 32
L/Do = 70/40 = 1.75

(2) Cylinders having Do /t values <10:
UG-28

ASME II Part D
SUBPART 3
CHARTS AND TABLES FOR DETERMINING
SHELL THICKNESS OF COMPONENTS UNDER
EXTERNAL PRESSURE
ASME II Part D for UG-28
UG-28
As stated in the API 510 Body of Knowledge, these charts will be
provided in the exam body, IF an external calculation is given on the examination.

ASME
VIII
Div.1-
Charlie
Chong/
Fion
Zhang/
He
Jungang
/
Li
Xueliang
FIG. G GEOMETRIC CHART FOR COMPONENTS UNDER EXTERNAL
OR COMPRESSIVE LOADINGS (for All Materials)
ASME II Part D for UG-28 UG-28

ASME
VIII
Div.1-
Charlie
Chong/
Fion
Zhang/
He
Jungang
/
Li
Xueliang

2007 SECTION II, PART D (METRIC) FIG. CS-1 CHART FOR DETERMINING SHELL THICKNESS OF
COMPONENTS UNDER EXTERNAL PRESSURE WHEN CONSTRUCTED OF CARBON OR LOW ALLOY STEELS
(Specified Minimum Yield Strength 165 MPa to, but Not Including, 205 MPa) [Note (1)]

UG-32 FORMED HEADS, AND SECTIONS,
PRESSURE ON CONCAVE SIDE.
UG-32

Hemispherical
Conical
Torispherical
Ellipsoidal
Formula
Disk Head Type
UG-32

Ellipsoidal

Torispherical

Hemispherical

D = inside diameter of the head skirt; or
inside length of the major axis of an
ellipsoidal head; or inside diameter of a
conical head at the point under
consideration, measured perpendicular to
the longitudinal axis.
Di = inside diameter of the conical portion
of a toriconical head at its point of
tangency to the knuckle, measured
perpendicular to the axis of the cone
= D − 2r (1 − cos α )
E= lowest efficiency of any joint in the
head; for hemispherical heads this
includes head-to-shell joint; for welded
vessels, use the efficiency specified in
UW-12
L = inside spherical or crown radius.
The value of L for ellipsoidal heads
shall be obtained from Table UG-37.
P = internal design pressure (see UG-
21)
r = inside knuckle radius
S = maximum allowable stress value
in tension as given in the tables
referenced in UG-23, except as
limited in UG-24 and (e) below.
t = minimum required thickness of
head after forming
ts = minimum specified thickness of
head after forming, in. (mm). ts shall
be ≥ t
α = one-half of the included (apex)
angle of the cone at the centerline of
the head (see Fig. 1-4)

API510-7 Charlie Chong/ Fion Zhang/ He Jungang / Li Xueliang UG-32

There are three types of calculations for formed heads listed in the
Body of Knowledge: (1) Ellipsoidal, (2) Torispherical and (3)
Hemispherical.
A sketch and the formulae for thickness of each kind are below.
(1) (2) (3)

The symbols defined below are used in the formulas of this paragraph:
t = minimum required thickness of head after forming, in.
P = internal design pressure (see UG-21), psi.
D = inside diameter of the head skirt; or inside length of the
major axis of an ellipsoidal head; in.
S = maximum allowable stress value in tension.
E = lowest efficiency of any joint in the head; for hemispherical
heads this includes head-to-shell joint; for welded vessels,
use the efficiency specified in UW-12.
L = inside spherical or crown radius, in.

API510-7 Charlie Chong/ Fion Zhang/ He Jungang / Li Xueliang
Ellipsoidal Heads.
For pressures over 10 bar, ellipsoidal heads are often used. In cross-
section, the head resembles an ellipse, its radius varying
continuously. This results in a smooth transition between the dome
and the cylindrical part of the vessel. Ellipsoidal heads are deeper than
comparable torispherical heads.
The shape of the ellipsoidal head is defined by the ratio of the major
and minor axis. A standard arrangement on vessels is the 2:1 elliptical
head (see Figure 2). This will have a depth of head which is a quarter
of the vessel’s internal diameter, D. The thickness of this type of head
is normally equal to the thickness of the cylinder to which it is
attached.
UG-32

2:1 Ellipsoidal head
This is also called a 2:1 elliptical head. The shape of this head is more
economical, because the height of the head is just a quarter of the
diameter. Its radius varies between the major and minor axis.
UG-32

A 2:1 ellipsoidal head has one-half the minor axis, h, equal to one-
fourth of the inside diameter of the head skirt, D. SF is the skirt
length required by UG−32(l).
A 2:1 ellipsoidal head may be approximated with a head containing a
knuckle radius of 0.17D and a spherical radius (L) of 0.90D.
UG-32

2:1 ellipsoidal head:
(d) Ellipsoidal Heads With ts /L ≥ 0.002. The required thickness of a dished head of
semi ellipsoidal form, in which half the minor axis (inside depth of the head minus the
skirt) equals one-fourth of the inside diameter of the head skirt, shall be determined by
NOTE: An acceptable approximation of a 2:1 ellipsoidal head is one with a knuckle
radius of 0.17D and a spherical radius (L) of 0.90D.
Note:
D = inside diameter of head skirt.
t = minimum required thickness after forming.
ts = minimum specified thickness after forming, ts ≥ t.
L = inside spherical or crown radius. The value of L for ellipsoidal heads shall be
obtained from Table UG-37.
UG-32

Non-2:1 ellipsoidal head;
Appendix 1−4 gives the following formulas for ellipsoidal heads with D/2h ratios
other than 2:1.
Where K1D is the equivalent spherical radius
UG-32

other than 2:1.
UG-32
2:1 ellipsoidal head:

Example: Standard 2:1
ellipsoidal head; h=D/4
D/2h = 2 ,K1 = 0.90#
For non 2:1 head, the radius to
use in the hemi-spherical head
formula shall be the equivalent
spherical radius.
GENERAL NOTES:
(a) Equivalent spherical radius = K1D; D/2h = axis ratio.
(b) For definitions, see 1-4(b).
(c) Interpolation permitted for intermediate values.
UG-32

other than 2:1.
UG-32
Example: Standard 2:1 ellipsoidal head; h=D/4
D/2h = 2 ,K1 = 0.90#

Ellipsoidal head calculation example
Here is an example for a 2:1 ellipsoidal head, using similar figures from the previous
example. Guides:
D = inside diameter of 60 in
P = pressure of 250 psi (MAWP)
E = 0.85 (double-sided butt weld with spot examination (UW-12))
S = 15800 psi
What thickness is required to resist the internal pressure?
t = 0.56 in. ANSWER
Assuming a given head thickness of 0.625 in
What is the MAWP?
P = 279 psi ANSWER
UG-32

Torispherical Heads - A torispherical (or flanged and dished) head
is typically somewhat flatter than an elliptical head and can be the
same thickness as an elliptical head for identical design conditions
and diameter. The minimum permitted knuckle radius of a
torispherical head is 6% of the maximum inside crown radius. The
maximum inside crown radius equals the outside diameter of the
head.
UG-32

(e) Torispherical Heads With ts/L ≥ 0.002. The required thickness of a torispherical
head for the case in which the knuckle radius is 6% of the inside crown radius and the
inside crown radius equals the outside diameter of the skirt [see UG-32(j)] shall be
determined by
NOTE: For torispherical heads with ts /L < 0.002, the rules of 1-4(f) shall also be met.
Torispherical heads made of materials having a specified minimum tensile strength
exceeding 70,000 psi (500 MPa) shall be designed using a value of S equal to 20,000 psi
(150 MPa) at room temperature and reduced in proportion to the reduction in maximum
allowable stress values at temperature for the material (see UG-23).
UG-32

 Knuckle radius is 6% of the inside crown radius
 The inside crown radius equals the outside
diameter of the skirt
UG-32

Torispherical head example
Given:
L = inside spherical (crown) radius of 30 in
P = pressure of 250 psi (MAWP)
E = 0.85
S = 15 800 psi
Thickness required (t)
t = 0.496 in ANSWER
Alternatively, to find P using a given head thickness of 0.625 in.:
Pressure (P) = 315 psi ANSWER
UG-32

R=Do
r = 0.06Do
UG-32

Hemispherical Heads - The required thickness of a hemispherical
head is normally one-half the thickness of an elliptical or torispherical
head for the same design conditions, material, and diameter.
Hemispherical heads are normally fabricated from segmented sections
that are welded together, spun, or pressed. Hemispherical heads are an
economical option to consider when expensive alloy material is used.
In carbon steel construction, hemispherical heads are generally not as
economical as elliptical or torispherical heads because of higher
fabrication cost. Carbon steel hemispherical heads may be economical
for thin, very large diameter vessels, or in thick, small-diameter
vessels.
The thickness transition zone between the hemispherical head and
shell must be contoured to minimize the effect of local stress. Figure
4.8 shows the thickness transition requirements that are contained in
the ASME Code.
UG-32

Thickness Transition Between Hemispherical Head and Shell
UG-32

(f) Hemispherical Heads. When the thickness of a hemispherical
head does not exceed 0.356L, or P does not exceed 0.665SE, the
following formulas shall apply:
UG-32

Hemispherical heads while they can be formed seamless are not
considered seamless heads by Section VIII. As mentioned previously
they essentially form a Category “A” seam between the head and the
other part. They are never seamless; their Joint E comes from Table
UW-12 based on the Type of weld and the extent of Radiography
applied.
E, based on the Type
of weld and the
extent of Radiography
applied.

Hemispherical head example
Given:
Internal pressure (P) = 200 psi
Allowable stress (S) = 15 000 psi
Spherical radius (L) = 60 in
Joint efficiency (E) = 1.0
Required thickness (t)
t = 0.401 in. ANSWER#
Alternatively, calculating the maximum allowable pressure for a given thickness of, say,
0.5 in.:
P = 250 psi ANSWER#
UG-32

Example: For the same pressure, stress and, dimension values will be used for all
heads. Let’s determine which type of head will be the thickest required and which
will be the thinnest allowed.
Given:
P = 100 psi
S = 17500 PSI
E = .85 for spot RT of hemispherical head joint to shell
E = 1.0 for seamless heads ( Ellipsoidal and Torispherical )
L = 48" for the inside spherical radius for the hemispherical head
L = 96" for the inside crown radius of the torispherical head
D = 96" inside diameter of the ellipsoidal
t = ? Required wall thickness, inches

t = (100x48)/(2x17500x0.85-0.2x100)
t = 0.162”
Hemispherical
t = (0.885x100x96)/(17500x1-0.1x100)
T= 0.486”
Torispherical
t = (100x96) / (2x17500x1-0.2x100)
t = 0.275”
Ellipsoidal
thickness
Equation
Head

(g) Conical Heads and Sections (Without Transition Knuckle). The required thickness of
conical heads or conical shell sections that have a half apex-angle not greater than 30
deg shall be determined by
A reinforcing ring shall be provided when required by the
rule in 1-5(d) and (e).
Conical heads or sections having a half apex-angle
greater than 30 deg without a transition knuckle shall comply
with Formula (4) and 1-5(g).
(h) Toriconical Heads and Sections
UG-32

Example of conical head calculation
Given:
Internal pressure (P) = 300 psi
Inside diameter of cone (D) = 40 in
Allowable stress (S) = 12 000 psi
Joint efficiency (E) = 0.85
Cone half angle (α) = 308
Cosine of 30o = 0.866
Calculating required thickness (t):
t = 0.69 in ANSWER
Alternatively calculating the maximum allowable pressure
for a given head thickness of, say, 0.75 in:
P = 325 psi ANSWER
UG-32

Torispherical head: These heads have a dish with a fixed radius (r1), the
size of which depends on the type of torispherical head. The transition
between the cylinder and the dish is called the knuckle. The knuckle has a
toroidal shape.
Note: The inside crown radius to which an unstayed formed head is
dished shall be not greater than the outside diameter of the skirt of the
head. The inside knuckle radius of a torispherical head shall be not less
than 6% of the outside diameter of the skirt of the head but in no case
less than three times the head thickness.
Torispherical Heads. The required thickness and the design pressure of a
torispherical head is calculated by the following formulas:
The following equations apply:

http://www.engineersedge.com/calculators/Torispherical-Heads/pressure-vessel-torispherical-heads..htm

UG-36 OPENINGS IN PRESSURE VESSELS.
UG-36

The main things of interests in this paragraph to the API 510 inspector are the
following:
1. All references to dimensions apply to the finished construction after deduction for
material added as corrosion allowance.
2. Openings not subject to rapid fluctuations in pressure do not require
reinforcement other than that inherent in the construction under the following
conditions:
(a) The finished opening is not larger than:
• 3 ½ in. diameter in vessel shells or heads 3/8 in. or less in thickness
• 2 3/8 in. diameter in vessel shells or heads over 3/8 in. in thickness
(c) No two isolated un-reinforced openings, in accordance with the above shall have
their centers closer to each other than the sum of their diameters

(c) No two isolated un-reinforced openings, in accordance with the above shall
have their centers closer to each other than the sum of their diameters
Radius R1
Radius R2
Center to center > 2R1+2R2

UG-37 REINFORCEMENT REQUIRED FOR
OPENINGS IN SHELLS AND
FORMED HEADS.
UG-37

The ASME Code uses simplified rules to ensure that the membrane stresses are kept
within acceptable limits when an opening is made in a vessel shell or head When
the opening is made, a volume of material is removed from the pressure vessel.
This metal is no longer available to absorb the applied loads. The ASME Code
simplifies the design calculations by viewing the nozzle-to-vessel junction area in
cross section. This simplification permits the nozzle reinforcement calculations to
be made in terms of metal cross-sectional area rather than metal volume. The
ASME Code requires that the metal area that is removed for the opening must be
replaced by an equivalent metal area in order for the opening to be adequately
reinforced. The replacement metal must be located adjacent to the opening within
defined geometric limits. The replacement metal area may come from two sources:
 Excess metal that is available in the shell or nozzle neck that is not required for
pressure or to absorb other loads.
 Reinforcement that is added to the shell or nozzle neck.
UG-37

If a reinforcement pad is used, its material should have an allowable stress that is at
least equal to that of the pressure vessel shell or head material to which it is attached.
No credit can be taken for the additional strength of any reinforcement that has a
higher allowable stress. If reinforcement material with a lower allowable stress is
used, the reinforcement area must be increased to compensate for this.
UG-37

 ASME VIII, UG-37
Is the nozzle sufficiently
reinforced
 ASME VIII, UW-16
Are the nozzle welds of
adequate sizes.
UG-37

ASME VIII, UG-37 The code uses the principle
of the area replacement method
http://www.wermac.org/specials/branch_reinforced.html
UG-37

(a)Nomenclature. The symbols used in this paragraph are defined
as follows:
• A = total cross-sectional area of reinforcement required in the plane under
consideration (see Fig. UG-37.1) (includes consideration of nozzle area through
shell if Sn /Sv<1.0)
• A1=area in excess thickness in the vessel wall available for reinforcement (see
Fig. UG-37.1) (includes consideration of nozzle area through shell if Sn /Sv<1.0)
• A2=area in excess thickness in the nozzle wall available for reinforcement (see
Fig. UG-37.1)
• A3=area available for reinforcement when the nozzle extends inside the vessel
wall (see Fig. UG-37.1) (Not in the exam)
• A5=cross-sectional area of material added as reinforcement (see Fig. UG-37.1)
• A41, A42, A43=cross-sectional area of various welds available for reinforcement
(see Fig. UG-37.1)
UG-37

FIG. UG-37.1 NOMENCLATURE AND FORMULAS FOR REINFORCED
OPENINGS
UG-37

The left-hand side shows the
configuration in which the nozzle
is ‘set through’ the shell. You can
ignore this as the set-through
configuration is specifically
excluded from the API syllabus.
set on to the shells – abuts.
UG-37

If A1+A2+A41+A5≥A
Opening is adequately reinforced
UG-37

UG-40 LIMITS OF
REINFORCEMENT
An opening is adequately reinforced if:
A1 + A2 + A3 + A41 + A42 + A5 > A
UG-40

tn
trn
tr
t
te
Smaller of 2.5t
or 2.5tn+te
Larger of d or Rn+tn+t
A1
A2
A5
A4
UG-40

Larger of d or Rn+tn+t
Shell plate
remove
area (A)
Spare area
available in
nozzle A2
Material
available in
weld A4
Material available
in pad A5
Spare material
available in
shell A1
Smaller of 2.5t
or 2.5tn+te
t
tn
te
UG-40

UG-84 CHARPY IMPACT TESTS

CHARPY IMPACT TESTS
UG-84

UG-84(a) General.
Charpy impact tests in accordance with the provisions of this paragraph
shall be made on weldments and all materials for shells, heads, nozzles,
for which impact tests are required by the rules in Subsection C.
UG-84(b) Test Procedures.
UG-84(b)(1) Impact test procedures and apparatus shall conform to the
applicable paragraphs of SA-370. SA-370 is a document that describes
in great detail the actual procedure for breaking specimens.
UG-84(c) Test Specimens.
UG-84(c)(1) Each set of impact test specimens shall consist of three
specimens.
UG-84

UG-84(g) Location, Orientation, Temperature, and Values of Weld
Impact Tests. All weld impact tests shall comply with the following:
UG-84(g)(1) Each set of weld metal impact specimens shall be taken
across the weld with the notch in the weld metal. Each specimen shall
be oriented so the notch is normal to the surface of the material and one
face of the specimen shall be within 1/16 in. (1.6 mm) of the surface of
the material.
UG-84(g)(2) Each set of heat affected zone impact specimens shall be
taken across the weld and of sufficient length to locate, after etching,
the notch in the heat affected zone. The notch shall be cut
approximately normal to the material surface in such a manner as to
include as much heat affected zone material as possible in the resulting
fracture.
UG-84

UG-84(h) Impact Tests of Welding Procedure Qualifications
• UG-84(h)(1) General. For steel vessels of welded construction, the
impact toughness of the welds and heat affected zones of the procedure
qualification test plates shall be…...UG-84(h)(2) When Required.
Welding procedure impact tests shall be made when required by UCS-67,
UHT-82, or UHA-51. For vessels constructed to the rules of Part UCS,
the test plate material shall satisfy all of the following requirements……
a) be of the same P-Number and Group Number;
b) be in the same heat treated condition; and
c) meet the minimum notch toughness requirements of UG-84(c)(4) for the
thickest material of the range of base material qualified by the procedure.
• (UG-84(h)(3) Material Over 1 ½ in. Thick. When procedure tests are
made on material over 1 ½ in. (38 mm) thick, three sets of impact
specimens are required.

UG-84(g3): One set of heat affected zone specimens shall be taken as
described in (g)(2). Two sets of impact specimens shall be taken from
the weld with one located within 1/16” the surface of one side of the
material and one set taken as near as practical midway between the
surface and the center of thickness of the opposite side as described in
(g)(1) above.

GENERAL NOTES:
a) Interpolation between yield strengths shown is permitted.
b) The minimum impact energy for one specimen shall not be less than 2⁄3 of the
average energy required for three specimens. The average impact energy value
of the three specimens may be rounded to the nearest ft-lb.
c) Material produced and impact tested in accordance with SA-320, SA-333, SA-
334, SA-350, SA-352, SA-420, impact tested SA/AS 1548 (L impact
designations), SA-437, SA-540 (except for materials produced under Table 2,
Note 4 in SA-540), and SA-765 do not have to satisfy these energy values. See
UCS-66(g).
d) For materials having a specified minimum tensile strength of 95 ksi or more, see
UG-84(c)(4)(b).

Criteria for Acceptance & Retest.
Figure UG-84.1.
1. The average energy of 3 specimen shall equal or exceed FIG. UG-
84.1 CHARPY V-NOTCH IMPACT TEST REQUIREMENTS
2. The minimum impact energy for one specimen shall not be less
than 2⁄3 of the average energy required for three specimens.
Note: For acceptance, average of 3 shall equal or exceed the
specified value and one (only one) may be below but shall exceed
2/3 the specified value.

Criteria for Retest.
UG-84(c)(6)
When the average value of the three specimens equals or exceeds the minimum
value permitted for a single specimen (2/3 specified average) and
(1) the value for more than one specimen is below the required average value, or
(2) when the value for one specimen is below the minimum value permitted for a
single specimen,
a retest of three additional specimens shall be made. The value for each of these
retest specimens shall equal or exceed the required average value.
Example: SMYS=50ksi, t=2 in. average value of the three specimens ≥18f-lb.
Minimum impact energy for one specimen 2/3 x 18 = 12 ft-lb.
1st Criteria for retest, 3 specimen average ≥ 12 ft-lb.

UG-84
Testing
FIG. UG-84.1 &
General Notes.
Accept
Satisfy
UG-84(c)(6)
Retest allowed
with stringent
requirement.
Reject

Example:
Average required is 15 ft-lb (joules 20.4)
Minimum value permitted for single specimen is 10 ft-lb.
•15 + 16 + 14 = 45/3 = 15 Passed.
•18 + 14 + 13 = 45/3 = 15 Failed, more than one below 15 (retest allowed)
•15 + 14 + 13 = 42/3 = 14 Failed, more than one below 15 (retest allowed)
•18 + 18 + 9 = 45/3 = 15 Failed, one below 2/3 of 15 = 10 (retest allowed)

UG-99 STANDARD HYDROSTATIC TEST
UG-99

STANDARD HYDROSTATIC TEST
UG-99

UG-99 STANDARD HYDROSTATIC TEST
1999 addendum and later:
Test Pressure in psi (MPa)
= 1.3 MAWP × (Stest temp /Sdesign temp)
Prior to 1999 addendum:
Test Pressure in psi (MPa)
= 1.5 MAWP × (Stest temp /Sdesign temp)
Lowest stress ratio (LSR) for the materials of which the vessel is constructed.
The stress ratio for each material is the stress value S at its test temperature to the
stress value S at its design temperature (Stest temp /Sdesign temp)
UG-99

Note that where a vessel is constructed of different
materials that have different allowable stress values, the
lowest ratio of stress values is used. You will see this
used later in ASME VIII worked examples.
Loweststress ratio (LSR) for the materials of which the vessel is constructed.
The stress ratio for each material is the stress value S at its test temperature to the
stress value S at its design temperature
(S test temp / S design temp)
UG-99

UG-99(g): The visual inspection of joints and connections for leaks at the test pressure
divided by 1.3 may be waived provided: ( Visual inspection at MAWP)
1. a suitable gas leak test is applied;
2. substitution of the gas leak test is by agreement reached between Manufacturer and
Inspector;
3. all welded seams which will be hidden by assembly be given a visual examination
for workmanship prior to assembly;
4. the vessel will not contain a “lethal” substance.
UG-99

Testing Medium.
 Any nonhazardous liquid at any temperature may be used for the hydrostatic test if
below its boiling point.
 Combustible liquids having a flash point less than 110ºF (43 ºC), such as petroleum
distillates, may be used only for near atmospheric temperature tests.
Metal temperature.
 It is recommended that the metal temperature during hydrostatic test be maintained
at least 30 ºF (17 ºC) above the minimum design metal temperature, but need not
exceed 120 ºF (48 ºC), to minimize the risk of brittle fracture. [See UG-20 and
General Note (6) to Fig. UCS-66.2.]
 The test pressure shall not be applied until the vessel and its contents are at about
the same temperature.
 If the test temperature exceeds 120 ºF (48 ºC), it is recommended that inspection of
the vessel required by (g) above be delayed until the temperature is reduced to 120 º
F (48 ºC) or less.
UG-99

Testing Medium.
 Any nonhazardous liquid at any temperature may be used for the hydrostatic test if
below its boiling point.
 Combustible liquids having a flash point less than 110°F (43 °C), such as
petroleum distillates, may be used only for near atmospheric temperature tests.
Metal temperature.
 It is recommended that the metal temperature during hydrostatic test be maintained
at least 30°F (17°C) above the minimum design metal temperature, but need not
exceed 120°F (48°C), to minimize the risk of brittle fracture. [See UG-20 and
General Note (6) to Fig. UCS-66.2.].
 The test pressure shall not be applied until the vessel and its contents are at about
the same temperature.
 If the test temperature exceeds 120°F (48°C), it is recommended that inspection
of the vessel required by UG-99(g) above be delayed until the temperature is
reduced to 120°F (48°C) or less.
UG-99

Metal temperature
API 510 has a different rule for this, it recommends that the temperature
be 10°F above for 2 in. (≤50mm) thickness and under and 30°F
above for over 2 in. (>50mm).
UG-99

Testing Medium.
 Any nonhazardous liquid at any temperature may be used for the
hydrostatic test if below its boiling point.
 Combustible liquids having a flash point less than 110°F (43°C),
such as petroleum distillates, may be used only for near atmospheric
temperature tests.
UG-99

Example: Hydrostatic testing pressure
Design pressure (MAWP) = 250 psi
Design temperature = 750°F
Material: carbon steel SA516-60
. S room = 15 000 psi
. S 750°F = 13 000 psi
Ratio of stress values = 15 000/13 000 = 1.154
Test pressure = 1.3x 250x 1.154
Test pressure = 375 psi. ANSWER#
UG-99

CAUTION: A small liquid relief valve set to 1⅓ (1.33) times the test pressure
is recommended for the pressure test system, in case a vessel, while under
test, is likely to be warmed up materially with personnel absent.
likely to be;
warmed up materially with personnel absent.

UG-99(k) Vessels, except for those in lethal service, may be
painted or otherwise coated either internally or externally,
and may be lined internally, prior to the pressure test.
However, the user is cautioned that such painting / coating /
lining may mask leaks that would otherwise have been
detected during the pressure test.

UG-100 PNEUMATIC TEST.
UG-100

• UG-100 (d) The pressure in the vessel shall be gradually increased to not more
than one-half of the test pressure. Thereafter, the test pressure shall be increased
in steps of approximately one-tenth of the test pressure until the required test
pressure has been reached. Then the pressure shall be reduced to a value equal to
the test pressure divided by 1.1 and held for a sufficient time to permit inspection
of the vessel. 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. The visual
inspection of the vessel at the required test pressure divided by 1.1 may be
waived provided:
2. substitution of the gas leak test is by agreement reached between Manufacturer
and Inspector;
3. all welded seams which will be hidden by assembly be given a visual
examination for workmanship prior to assembly;

2. substitution of the gas leak test is by agreement reached between Manufacturer
and Inspector;
3. all welded seams which will be hidden by assembly be given a visual
examination for workmanship prior to assembly;

the pneumatic test pressure at every point in the vessel shall be at least equal to 1.1
times the maximum allowable working pressure multiplied by the lowest stress ratio
(LSR) for the materials of which the vessel is constructed.
The pressure in the vessel shall be gradually increased to not more than one-half of
the test pressure. Thereafter, the test pressure shall be increased in steps of
approximately one-tenth of the test pressure until the required test pressure has
been reached. Then the pressure shall be reduced to a value equal to the test pressure
divided by 1.1 and held for a sufficient time to permit inspection of the vessel.
Pneumatic test pressure = 1.1 x MAWP x LSR
UG-100

Test pressure divided by 1.1 and held for a sufficient
time to permit inspection of the vessel.
UG-100

“Test pressure divided by 1.1” is not MAWP!
There is a LSR factor.
UG-100

UG-100 (e) Vessels, except for those in lethal service, may be painted
or otherwise coated either internally or externally, and may be lined
internally, prior to the pressure test. However, the user is cautioned
that such painting / coating /lining may mask leaks that would
otherwise have been detected during the pressure test.

UW-50 NONDESTRUCTIVE EXAMINATION
OF WELDS ON PNEUMATICALLY TESTED VESSELS
On welded pressure vessels to be pneumatically tested in accordance with UG-100,
the full length of the following welds shall be examined7 for the purpose of
detecting cracks:
a) all welds around openings;
b) all attachment welds, including welds attaching non-pressure parts to pressure
parts, having a throat thickness greater than 1⁄4 in. (6 mm).
Note:
7 Examination shall be by magnetic particle or liquid penetrant methods
when the material is ferromagnetic, or by the liquid penetrant method
when the material is nonmagnetic.
UG-100

a) all welds around openings;
b) all attachment welds, including welds attaching non-pressure parts to pressure
parts, having a throat thickness greater than 1⁄4 in. (6 mm).
UG-100

Q8. ASME VIII UG-100 (d): pneumatic test
What are the increments used to increase the pressure up to pneumatic test pressure?
(a) Increase gradually to 50 % design pressure followed by 10 % increments
(b) Increase gradually by 10 % increments
(c) Increase gradually to 50 % test pressure followed by 10 % increments
(d) Increase gradually to 1.3x design pressure followed by 10 % increments
UG-100

UG-102 TEST GAGES

UG-102:
(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 1 ½ 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.
Applicable testing range 40psi~107psi
UG-102

UG-102:
the gauge
range be
within
1½ and 4
times that of
test pressure.
Applicable test pressure range:
37.7 ~100psi
UG-102

API576-5.4.5 Incorrect calibration of pressure gauges is a frequent cause of
improper valve setting. To ensure accuracy, gauges should be calibrated frequently on a
regularly calibrated dead weight tester. The pressure range of the gauge should be
chosen so that the required set pressure of the pressure-relief valve falls within the
middle third of the gauge pressure range. Snubbers on pressure gauges are not generally
recommended since they tend to clog and produce pressure lag.
Applicable test range: 50~100psi
UG-102
middle third

Snubbers on pressure gauges are not generally recommended since they tend to
clog and produce pressure lag.
UG-102
A snubber is a device used to suppress ("snub")
some phenomenon, such as:
• Voltage transients in electrical systems.
• Pressure transients in fluid systems.
• Excess force or rapid movement in
mechanical systems.

a) An indicating gage shall be connected directly to the vessel.
If the indicating gage is not readily visible to the operator
controlling the pressure applied, an additional indicating
gage shall be provided where it will be visible to the
operator throughout the duration of the test. For large
vessels, it is recommended that a recording gage be used in
addition to indicating gages.
b) Dial indicating pressure gages used in testing shall be
graduated over a range of about double (2X) the intended
maximum test pressure, but in no case shall the range be
less than 1 ½ 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.
c) All gages shall be calibrated against a standard deadweight
tester or a calibrated master gage. Gages shall be
recalibrated at any time that there is reason to believe that
they are in error.
UW-102

c) All gages shall be calibrated against a standard deadweight
tester or a calibrated master gage. Gages shall be
recalibrated at any time that there is reason to believe that
they are in error.
UW-102

UG-116 REQUIRED MARKING.

UG-116(e4) “RT 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.
RT 4
UG-116(e3) “RT 3”
when the complete vessel satisfies the spot radiography requirements of
UW-11(b); or
RT 3
UG-116(e2) “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 2
UG-116(e1) “RT 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 1 1⁄8 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 Manufacturer’s
Data Report; or
RT 1

UW-11 RADIOGRAPHIC AND ULTRASONIC EXAMINATION
(a) Full Radiography. The following welded joints shall be examined radiographically
for their full length in the manner prescribed in UW-51:
(5) all Category A and D butt welds in vessel sections and heads where the design of
the joint or part is based on a joint efficiency permitted by UW-12(a), in which
case:
(a) Category A and B welds connecting the vessel sections or heads shall be of Type
No. (1) or Type No.(2) of Table UW-12;
(b) Category B or C butt welds [but not including those in nozzles or communicating
chambers except as required in (2) above] which intersect the Category A butt welds
in vessel sections or heads or connect seamless vessel sections or heads shall, as a
minimum, meet the requirements for spot radiography in accordance with UW-52.
Spot radiographs required by this paragraph shall not be used to satisfy the spot
radiography rules as applied to any other weld increment.

Required Marking
• The marking applied to a vessel's nameplate or directly to its shell are described
in this paragraph. It is important information. Often a vessel's Data Report is
lost and the only information that is available is that found on the Name Plate
or the shell itself. In some cases the Name Plate is missing or sand blasted and
not readable. The following is a listing of what is required by the Code to be
present on the Name Plate.
1. The official Code U or UM symbol. If inspected by the Owner/User of the
vessel the word USER shall be marked on the vessel.
2. Name of the manufacturer preceded by the words "Certified by".
3. Maximum allowable working pressure ____psi at __°F.
4. Minimum design metal temperature __°F at ____ psi.
5. Manufacturer's serial number.
6. Year built.
7. The type of construction used for the vessel must be marked directly under the
Code symbol by the use of the appropriate letter as listed in the Code.

8. If a vessel is built using more than one type of construction all shall be
indicated.
9. If a vessel is in a special service the lettering as shown below must be applied.
a. a. Lethal Service L.
b. b. Unfired Steam Boiler UB.
c. c. Direct Firing DF.
11.10. The MAWP must be based on the most restrictive part of the vessel.

11.When a complete vessel or parts of a vessel of welded construction have been
radiographed in accordance with UW-11, the marking must be as follows:
a. "RT 1" when all pressure retaining butt welds, other than B and C associated
with nozzles and communication chambers that neither exceed NPS 10 nor 1
1/8 inch thickness have been radiographically examined for their full length in
a manner prescribed in UW 51, full radiography of the above exempted
Category B and C butt welds if performed, may be recorded.
b. "RT 2" Complete vessel satisfies UW-11(a)(5) and UW- 11(a)(5)(b) has been
applied.
c. "RT 3" Complete vessel satisfies spot radiography of UW-11(b).
d. "RT 4" When only part of the vessel satisfies any of the above.

12.The letters HT must be used when the entire vessel has been Postweld heat
treated.
13.The letter PHT when only part of the vessel has received partial Postweld heat
treatment.
14.Code symbol must be applied after hydro or pneumatic test.
15.Parts of vessels for which Partial Data Report are required shall be marked by
the parts manufacturer with the following:
a. "PART“.
b. Name of the Manufacturer.
c. The manufacturer's serial number.

"RT 2" Complete vessel satisfies UW-11(a)(5) and UW-
11(a)(5)(b) has been applied.
UW-11 RADIOGRAPHIC AND ULTRASONIC EXAMINATION
(a) Full Radiography. The following welded joints shall be examined
radiographically for their full length in the manner prescribed in UW-51:
(5) all Category A and D butt welds in vessel sections and heads where the design of
the joint or part is based on a joint efficiency permitted by UW-12(a), in which
case:
(b) Category B or C butt welds [but not including those in nozzles or
communicating chambers except as required in (2) above] which intersect the
Category A butt welds in vessel sections or heads or connect seamless vessel
sections or heads shall, as a minimum, meet the requirements for spot
radiography in accordance with UW-52. Spot radiographs required by this
paragraph shall not be used to satisfy the spot radiography rules as applied to any
other weld increment.

When and where is there a code requirement for full radiography?
Item 1: All butt welds in vessels used to contain a lethal substance (UW-11(a)).
Lethal substances have specific definitions in ASME Code in UW-2 and it is the
responsibility of the end user to determine if they ordered a vessel that contains lethal
substances.
Item 2: All butt welds in vessels in which the nominal thickness exceeds specified
values (UW-11(a)). You can find these values in subsection C, in UCS-57, UNF-57,
etc. For example, this value for P-No.1 in UCS-57 is 1 ¼ inch.
Item 3: All butt welds in an unfired steam boiler with design pressure > 50 psi (UW-
11(a)).
Item 4: All category “A” and “D” butt welds in vessel when “Full Radiography”
optionally selected from table UW-12(column (a) in this table is selected); and
categories B and C which intersect Category “A” shall meet the spot radiography
requirement (UW-11(a) (5) (b)).

Item 4: All category “A” and “D” butt welds in vessel when “Full Radiography”
optionally selected from table UW-12(column (a) in this table is selected); and
categories “B” and “C” which intersect Category A shall meet the spot radiography

The point is this: items 1, 2 and 3 are similar, but item 4 is completely different.
In items 1, 2 and 3 it is mandated by code; to do full radiography in all butt welds in
vessel so it means it is mandatory for designer to select column (a) in UW-12 table. But in
item 4, there is no mandating rule. A manufacturer with its own decision has chosen to
use column (a) in table UW-12 for full radiography. So here there is a concession or
bonus to manufacturers for joint categories B and C.
What is concept behind this concession or bonus in pressure vessel RT test?
If you review item 1, 2 and 3 one more time, you will see that the pressure vessel RT tests
are related to the type of welds and services. You can see the pressure vessels in these
items are critical from a safety point of view, one contains a lethal substance, the other
one has a high thickness, which implicates high pressure, and the last one is an unfired
steam boiler. But item 4 has no criticality like the other items have. But you should note
all 4 items have been categorized in full radiography clause( U-11(a)), so to differentiate
item 1, 2 and 3 from item 4, the RT symbols (RT1 / RT2) are used in Code (UG-116).

Lethal service / thickness
/ unfired steam boiler.
RT 1 All butt welds
in vessels. (categories A, B,
C, D)
RT 2 All category “A”
and “D” butt welds in vessel and
categories “B” and “C” which
intersect Category “A” shall
meet the spot radiography
Optionally selected “E” from
table UW-12(column a).

RT 1: Items 1, 2 and 3, (E=1), All butt welds-full length radiography
RT 2: Item 4 (E=1), Category A and D butt welds full length
radiography and category B and C butt welds spot Radiography
RT 3: (E=0.85), Spot radiography butt welds
RT 4: (E=0.7), Partial / No radiography
http://www.inspection-for-industry.com/asme-pressure-vessel-joint-efficiencies.html

http://www.nationalboard.org/PrintPage.aspx?NewsPageID=144
Q. What is the difference between an RT-1 and an RT-2 vessel?
A. The definitions for the RT-1 and RT-2 are provided in paragraph UG-
116(e) and, by reference, UW-11(a). Paragraph UW-11(a) defines both
plans as full radiography. The RT-1 plan requires all butt-welded joints
be fully radiographed over their entire length using the criteria in
paragraph UW-51. The RT-2 plan requires all category A and D butt-
welded joints be radiographed over their entire length using the criteria in
paragraph UW-51. All category B and C butt-welded joints must be spot
radiographed per UW-11(a)(5)(b) using the criteria in paragraph UW-52.
Depending on the welded joint type employed for welded components,
the efficiency will normally be established by a category A or D butt-
welded joint (UG-27 footnote 15). A vessel complying with either plan
will be 100 percent efficient for both components having type 1 welded
joints (Table UW-12 column [a]) and seamless head or shell sections
(UW-12[d]).

UG-119 Nameplates

UG-119 Nameplates.
In this paragraph are the details of nameplates, including such things
as the size and methods of markings allowed. The nameplate must be
located within 30 in. of the vessel and must be thick enough to resist
distortion when stamping is applied. The types of acceptable
attachment types include welding, brazing, and tamper resistant
mechanical fasteners of metal construction. Adhesive attachments may
be used if the provisions of Appendix 18 are met. An additional
nameplate may be used if it is marked with the words "DUPLICATE".
On previous tests some questions have come from this paragraph.

UG-120 Data Reports
UW-120

UG-120 Data Reports
Data Reports must prepared on form U-1 or U-1A for all vessels that
the Code Symbol will be applied to. The Manufacturer and the
Inspector must sign them. A single Data Report may represent all
vessel made in the same day production run if they meet all of the
requirements listed in UG-120. A copy of the Manufacturer's Data
Report must be furnished to the User and upon request the Inspector.
The manufacturer must either keep a copy of the Data Report on file
for 5 years or register the vessel and file the Data Report with the
National Board of Boiler and Pressure Vessel Inspectors.

ASME
VIII
Div.1-
Charlie
Chong/
Fion
Zhang/
He
Jungang
/
Li
Xueliang
UW-120

UW-120

ASME Section viii Div-1 Traing ppt..pdf

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