Asmeviii Ug Ppt 140819093434 Phpapp01

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Fion Zhang/ Charlie Chong

ASME VIII Div.1API510 2013 June.

My pre-exam self-study notes






Speaker: Fion Zhang 2013/April/15



http://slidepdf.com/reader/full/asmeviii-ug-ppt-140819093434-phpapp01 4/209Fion Zhang/ Charlie Chong



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 ALLMETHODS 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 wecannot 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



Fion Zhang/ Charlie Chong 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 thefollowing:

(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 pressureShell 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) stressThis 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 examthis 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.• R i = 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 thefact 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

7




F i g u r e 9 . 4 V

e s s e l s t r e s s e

s

U G - 2 7







A key feature of R i 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 R i of 10 in and has a corrosion rate(internal) of 0.1 in./years, with the next scheduled inspection in five years, then:

Current R i = 10 in.

R i in 5 years = 10 in. + (5 x 0.1 in) = 10.5 in corroded condition.Hence 10.5 in. is the R i dimension to use in the UG-27 equation.

UG-27

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.




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 exampleThe following information is given in the question.

R i = 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.R i = 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



Fion Zhang/ Charlie Chong 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 R cal or Dcal used in

calculation shall be the

vessel R Design or DDesign plusthe corrosion allowance.

The required wall thickness

shall be pressure thickness +

corrosion allowance t p+c

c =

Corrosion

Allowance

R design= Designedradius

Rcalculation

=

R design + c,

Radius used

for calculation

t p =thickness

required for

internal

pressure

P 250 i S 14400 i 0 125i




Lower section

2:1 ellipsoidal

head

Lower section

6’ID shell

Middle section

conical

Top section4’ID shell

Top

hemispherical

head

Section

1.0

0.85

0.85

0.85

1.0?

Required Thickness tp + cEquationE

P=250psig, S=14400psi, c=0.125in.

Dcal = 72 + 2 x 0.125 = 72.25 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 36 + 0.125 = 36.125 in.

P=250psig S=14400psi c=0 125in




Lower section

2:1 ellipsoidal

head

Lower section

6’ID shell

Middle section

conical


Top

hemispherical

head

Section

1.0

0.85

0.85

0.85

1.0?


P=250psig, S=14400psi, c=0.125in.

Dcal = 72 + 2 x 0.125 = 72.25 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 36 + 0.125 = 36.125 in.

UG 32( )



35Fion Zhang/ Charlie Chong UG-32

D = inside diameter of the head skirt; or insidelength 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 − cosα )

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. Thevalue 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)

P=250psig S=14400psi c=0 125in




Lower section

2:1 ellipsoidal

head

Lower section

6’ID shell

Middle section

conical


Top

hemispherical

head

Section

1.0

0.85

0.85

0.85

0.85


P 250psig, S 14400psi, c 0.125in.

Dcal = 72 + 2 x 0.125 = 72.25 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 24 + 0.125 = 24.125 in.

R cal = 36 + 0.125 = 36.125 in.

E i 2




Exercise 2

Required Thickness for Internal Pressure

Determine the minimum required thickness for the cylindrical shell and heads of thefollowing 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)

---------------------------------------------------------------------------

A




Answers:Inside diameter = 126 + 0.25 = 126.25 in. Ri= 63.125 in. S=14800psi, E=1.

Calculations:

Shell:

t p = (650x63.125)/(14800-0.6x650) =2.848 in.

tshell

= t p

+c = 2.847+0.125 = 2.973 in.#

Head:

t p = (650x126.25)/(2x14800-0.2x650) = 2.785 in.

Thead = t p+c=2.785+0.125=2.910 in.#

Appendix 1 Supplementary Design Formulas




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),

Exercise 3




Exercise 3

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 4




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 = .85What 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




You need to consider the hemispherical head joint to shell as category A, but




p j g y ,

ellipsoidal and torispherical head joint to shell as category B;

Do you know why? Why ASME considered the stringent rule for pressure vessel RTtest 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.

Example: For the same pressure stress and dimension values will be used for all




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

thicknessthicknessEquationEquationHeadHead




t = (100x48)/(2x17500x0.85t = (100x48)/(2x17500x0.85--0.2x100)0.2x100)t = 0.162t = 0.162””

HemisphericalHemispherical

t = (0.885x100x96)/(17500x1t = (0.885x100x96)/(17500x1--0.1x100)0.1x100)T= 0.486T= 0.486””

TorisphericalTorispherical

t = (100x96) / (2x17500x1t = (100x96) / (2x17500x1--0.2x100)0.2x100)t = 0.275t = 0.275””

EllipsoidalEllipsoidal

thicknessthicknessEquationEquationHeadHead




Spot radiography forellipsoidal and torispherical

heads (Cat. B). Full

radiography foe hemispherical

head (Cat. A).

UG 28 THICKNESS OF SHELLS AND TUBES




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 todesign 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 bewelded on either the inside or the outside of the shell.

UG-28




Basic Data (example)

Temperature = 500°F




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 inthe exam body,

IF an external

calculation is

given on theexamination.

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




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




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 vacuumduty (-14.5 psi ).

Pa should be≥14.5psi

UG-28





Example #1-2




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 besuitable 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




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 500oFSo 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




, p

be extremely precise. So now we have. From this point of intersection move erticallydownward to determine the value of factor A.

Do /t = 19

L/Do = 12

UG-28

U G - 2 8




D o / t = 1 9

, L / D o = 1 2

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 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 is500oF. 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

d bl (i 500 F)




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.




pp y

Step 6 Using this value of Factor B, calculate the value of themaximum allowable external pressure Pa using the following

formula:

UG-28


Example #3




Problem: A vessel is operating under an external pressure, the operating temperature is500° 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:




ASME II Part D

SUBPART 3




Charts and tables for determining shell thickness ofcomponents under external pressure

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 II Part D for UG-28

UG-28

X T E R N A L

U G - 2 8




F I G .

G G E O M E

T R I C C H A R T F O R C O M P O N E N T S U N D E R E

O R C O M P R E S S I V E L O A D I N G

S ( f o r A l l M a t e r i a l s )

A S M

E I I P a r t D

f o r U G - 2 8

U G - 2 8




A S M E I I P a r t D

f o r U G - 2 8

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)]




ASME II Part D for UG-28UG-28







UG-32 FORMED HEADS, AND SECTIONS,

PRESSURE ON CONCAVE SIDE.




Ellipsoidal

FormulaDisk Head Type




Hemispherical

Conical

Torispherical

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

i l h d t th i t d

L = inside spherical or crown radius.

The value of L for ellipsoidal heads

shall be obtained from Table UG-37.




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 − cosα )

E= lowest efficiency of any joint in the

head; for hemispherical heads this

includes head-to-shell joint; for weldedvessels, use the efficiency specified in

UW-12

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 ofhead 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)




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




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




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 headsthis includes head-to-shell joint; for welded vessels, use the

efficiency specified in UW-12.

L = inside spherical or crown radius, in.

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




the head resembles an ellipse, its radius varying continuously. This resultsin 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 andminor 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




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 theh d i th ki t) l f th f th i id di t f th h d ki t




head of semi ellipsoidal form, in which half the minor axis (inside depth of thehead 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




ratios other than 2:1.

Where K 1D is the equivalent spherical radius

UG-32

Non-2:1 ell ipsoidal head;

Appendix 1−4 gives the following formulas for ellipsoidal heads with D/2h






Where K1D is the equivalent spherical radius

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 = K 1D; D/2h = axis ratio.

(b) For definitions, see 1-4(b).

(c) Interpolation permitted for intermediate values.

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 K 1D is the equivalent spherical radius

UG-32

Example: Standard 2:1 ellipsoidal head; h=D/4

D/2h = 2 ,K1 = 0.90#


Ellipsoidal head calculation exampleHere 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




p gand 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 thehead.

UG-32

(e) Torispherical Heads With t s /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 t s /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




diameter of the skirt

UG-32

Torispherical head exampleGiven:

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




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-diametervessels.

The thickness transition zone between the hemispherical head and

shell must be contoured to minimize the effect of local stress. Figure4.8 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 0.356 L, or P does not exceed 0.665SE, the

following formulas shall apply:




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 Typeof weld and theextent of Radiographyapplied.

Hemispherical head exampleGiven:

Internal pressure (P) = 200 psiAllowable stress (S) = 15 000 psi




( ) p

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

thicknessEquationHead




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

(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 complywith Formula (4) and 1-5(g).

(h) Toriconical Heads and Sections

UG-32

Example of conical head calculationGiven:

Internal pressure (P) = 300 psi

Inside diameter of cone (D) = 40 in

Allowable stress (S) = 12 000 psi




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 thehead. 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.




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 constr ction nder the follo ing




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 R1Radius R2

Center to center > 2R 1+2R 2

UG-37 REINFORCEMENT REQUIRED FOR

OPENINGS IN SHELLS AND

FORMED HEADS.




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 Codesimplifies the design calculations by viewing the nozzle-to-vessel junction area in

cross section This simplification permits the nozzle reinforcement calculations to




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 bereplaced 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 isused, the reinforcement area must be increased to compensate for this.




ASME VIII, UG-37

Is the nozzle sufficiently

reinforced

ASME VIII, UW-16




ASME VIII, UW 16

Are the nozzle welds of

adequate sizes.

UG-37

ASME VIII, UG-37 The code uses the principleof 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 (seeFig. 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 REINFORCEDOPENINGS







The left-hand side shows the

configuration in which the nozzle

is ‘set through’ the shell. You can

ignore this as the set-throughconfiguration 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

A i i d l i f d if




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 R n+tn+t

A1

A2

A5

A4

UG-40




Spare area

available in

nozzle A2

Materialavailable in

weld A4

Material available

in pad A5

tn




Larger of d or R n+tn+t

Shell plate

remove

area (A)

Spare material

available in

shell A1

Smaller of 2.5t

or 2.5tn+te

t

n

te

UG-40




UG-84 CHARPY IMPACT TESTS




CHARPY IMPACT TESTS




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




p

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 betaken 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 toinclude 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, theimpact toughness of the welds and heat affected zones of the procedure

qualification test plates shall be…...UG-84(h)(2) When Required.

W ldi d i h ll b d h i d b UCS 67




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 aremade on material over 1 ½ in. (38 mm) thick, three sets of impact

specimens are required.

• (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.




Base material = 1 set of 3

Welding procedure t≤ 1 ½ “ = 2 sets of 3 (HAZ & Weld)

Welding procedure t > 1 ½ “ = 3 sets of 3 (HAZ & 2 sets of Weld)

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 thesurface and the center of thickness of the opposite side as described in

(g)(1) above




(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




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

( ) h l f h i i b l h i d l




(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)




18 + 18 + 9 45/3 15 Failed, one below 2/3 of 15 10 (retest allowed)

UG-99 STANDARD HYDROSTATIC TEST




STANDARD HYDROSTATIC TEST




UG-99 STANDARD HYDROSTATIC TEST

1999 addendum and later:

Test Pressure in psi (MPa)

= 1.3 MAWP× (Stest temp /Sdesign temp)




p g p

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 thestress value S at its design temperature (Stest temp /Sdesign temp)

UG-99

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

(S test temp / S design temp)




Note that where a vessel is constructed of differentmaterials that have different allowable stress values, the

lowest ratio of stress values is used. You will see thisused later in ASME VIII worked examples.

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 ºF (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 isreduced 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).




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.




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 (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




q p g p y

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:

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.

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.







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.

Pneumatic test pressure = 1.1 x MAWP x LSR




“Test pressure divided by 1.1” is not MAWP!

There is a LSR factor.




Pneumatic test pressure = 1 1 x MAWP x LSR

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) ll h ld i l di ld hi




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).




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-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




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 bewithin




1½ and 4times that oftest 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 themiddle third of the gauge pressure range. Snubbers on pressure gauges are not generally

recommended since they tend to clog and produce pressure lag.

middle third




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.

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




Excess force or rapid movement inmechanical 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 theoperator 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 begraduated over a range of about double (2X) the intended




b) Dial indicating pressure gages used in testing shall begraduated 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 thatthey are in error.




UG-116 REQUIRED MARKING.




UG-116(e2) “RT 2”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




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

( )

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

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




(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




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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 beindicated.

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 beenradiographed 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 11/8 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 ofthe joint or part is based on a joint efficiency permitted by UW-12(a) in which




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 orcommunicating 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




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 radiographyrequirement (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

requirement (UW-11(a) (5) (b)).




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 touse 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 unfiredsteam 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 radiographyrequirement (UW-11(a) (5) (b)).

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

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




http://www.nationalboard.org/PrintPage.aspx?NewsPageID=144

p g p g y j p

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 belocated 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




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




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 allvessel 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

f i h l d fil h i h h




for 5 years or register the vessel and file the Data Report with the

National Board of Boiler and Pressure Vessel Inspectors.




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