Page 1

ASME VIII Div.1 API510 2013 June. My pre-exam self-study notes

Fion Zhang/ Charlie Chong


Fion Zhang/ Charlie Chong


Speaker: Fion Zhang 2013/April/15

Fion Zhang/ Charlie Chong


Fion 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.

Fion Zhang/ Charlie Chong


Fion Zhang/ Charlie Chong


SUBSECTION A GENERAL REQUIREMENTS

Fion Zhang/ Charlie Chong


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

Fion Zhang/ Charlie Chong


Vessel design features

Fion Zhang/ Charlie Chong


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)

Fion Zhang/ Charlie Chong


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�.

Fion Zhang/ Charlie Chong


UG-20 DESIGN TEMPERATURE

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.

Fion Zhang/ Charlie Chong

UG-20


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.

Fion Zhang/ Charlie Chong

UG-20


UG-27 THICKNESS OF SHELLS UNDER INTERNAL PRESSURE.

Fion Zhang/ Charlie Chong

UG-27


Fion Zhang/ Charlie Chong

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:

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-27


Fion Zhang/ Charlie Chong

Figure 9.4 Vessel stresses

UG-27


Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-27


UG-27 ď Ž The thickness must not exceed one-half of the inside radius, i.e. it is not a thick cylinder. ď Ž 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.

Fion Zhang/ Charlie Chong


ď Ž 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.

Fion Zhang/ Charlie Chong

UG-27


Shell calculation example The following information is given in the question. = inside radius of 30 in . Ri 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

Fion Zhang/ Charlie Chong

UG-27


Shell calculation example The following information is given in the question. = inside radius of 30 in. Ri 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.

Fion Zhang/ Charlie Chong

UG-27


Fion Zhang/ Charlie Chong

UG-27


DESIGN INFORMATION • • • • • • • • • •

Fion Zhang/ Charlie Chong

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

UG-27


Summary Maximum Weld Joint Efficiency: Joint Type 1~6

Fion Zhang/ Charlie Chong

UW-12


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 700째F

Fion Zhang/ Charlie Chong

UG-27


If corrosion allowance is specified: (usually not in API510 exam)

Rcal for 6’ = 36.125” c= Corrosion Allowance tp = thickness required for internal pressure

Fion Zhang/ Charlie Chong

R calculation = R design + c, Radius used for calculation

R design= Designed radius

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

UG-27


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

E

Top hemispherical head

1.0?

Top section 4’ID shell

0.85

Equation

Required Thickness tp + c

.

Rcal = 24 + 0.125 = 24.125 in

Rcal = 24 + 0.125 = 24.125 in.

Middle section conical

0.85

Lower section 6’ID shell

0.85 Rcal = 36 + 0.125 = 36.125 in.

Lower section 2:1 ellipsoidal head Fion Zhang/ Charlie Chong

1.0 Dcal = 72 + 2 x 0.125 = 72.25 in.

UG-27


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

E

Top hemispherical head

1.0?

Top section 4’ID shell

0.85

Equation

Required Thickness tp + c

.

Rcal = 24 + 0.125 = 24.125 in

Rcal = 24 + 0.125 = 24.125 in.

Middle section conical

0.85

Lower section 6’ID shell

0.85 Rcal = 36 + 0.125 = 36.125 in.

Lower section 2:1 ellipsoidal head Fion Zhang/ Charlie Chong

1.0 Dcal = 72 + 2 x 0.125 = 72.25 in.

UG-27


UG-32(a) 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 headto-shell joint; for welded vessels, use the efficiency specified in UW-12

Fion Zhang/ Charlie Chong

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)

35 UG-32


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

E

Top hemispherical head

0.85

Top section 4’ID shell

0.85

Equation

Required Thickness tp + c

.

Rcal = 24 + 0.125 = 24.125 in

Rcal = 24 + 0.125 = 24.125 in.

Middle section conical

0.85

Lower section 6’ID shell

0.85 Rcal = 36 + 0.125 = 36.125 in.

Lower section 2:1 ellipsoidal head Fion Zhang/ Charlie Chong

1.0 Dcal = 72 + 2 x 0.125 = 72.25 in.

UG-27


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)

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

Fion Zhang/ Charlie Chong

UG-27


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.#

Fion Zhang/ Charlie Chong

UG-27


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),

Fion Zhang/ Charlie Chong

UG-27


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"

Fion Zhang/ Charlie Chong

UG-27


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 = .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

Fion Zhang/ Charlie Chong

UG-27


Fion Zhang/ Charlie Chong

UG-27


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.

Fion Zhang/ Charlie Chong

UG-27


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

Fion Zhang/ Charlie Chong

44 UG-32


Head

Equation

thickness

Ellipsoidal

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

Torispherical

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

Hemispherical

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

Fion Zhang/ Charlie Chong

45 UG-32


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

Fion Zhang/ Charlie Chong

UG-27


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

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Basic Data (example) Temperature = 500째F t = 0.530 in. L = 120 in. Do = 10 in. 1. 2.

Calculate Do/t 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

Fion Zhang/ Charlie Chong

UG-28


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.

Fion Zhang/ Charlie Chong

UG-28


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. Fion Zhang/ Charlie Chong

UG-28


3. Calculate P

Fion Zhang/ Charlie Chong

UG-28


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

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


UG-28, C(1)- Cylinders having Do /t values ≼ 10: 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) Âź in. (c) 3/8 in. (d) others. Fion Zhang/ Charlie Chong

UG-28


UG-28, C(1)- Cylinders having Do /t values ≥ 10: 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) = 120/10 = 12# L/Do

Fion Zhang/ Charlie Chong

UG-28


UG-28, C(1)- Cylinders having Do /t values ≼ 10: Example of Calculation using graphs Normally values A & B are given without using the ASME II graphs

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

UG-28


UG-28 Do/t = 19, L/Do = 12 Fion Zhang/ Charlie Chong


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.

Fion Zhang/ Charlie Chong

UG-28


Do/t = 19 L/Do = 12 A=0.0028

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


UG-28, C(1)- Cylinders having Do /t values ≥ 10: 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”

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

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 Fion Zhang/ Charlie Chong

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:

Fion Zhang/ Charlie Chong

UG-28


UG-28, C(1)- Cylinders having Do /t values ≥ 10: 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

Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


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

Fion Zhang/ Charlie Chong

UG-28


ASME II Part D SUBPART 3 Charts and tables for determining shell thickness of components 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 Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

ASME II Part D for UG-28

UG-28

FIG. G GEOMETRIC CHART FOR COMPONENTS UNDER EXTERNAL OR COMPRESSIVE LOADINGS (for All Materials)


Fion Zhang/ Charlie Chong

ASME II Part D for UG-28

UG-28


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-28 Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


Fion Zhang/ Charlie Chong

UG-28


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

Fion Zhang/ Charlie Chong

UG-32


Disk Head Type

Formula

Ellipsoidal

Torispherical

Hemispherical

Conical

Fion Zhang/ Charlie Chong

UG-32


Ellipsoidal

Fion Zhang/ Charlie Chong

UG-32


Torispherical

Fion Zhang/ Charlie Chong

UG-32


Hemispherical

Fion Zhang/ Charlie Chong

UG-32


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

Fion Zhang/ Charlie Chong

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 UG21) 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


Fion Zhang/ Charlie Chong

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)

Fion Zhang/ Charlie Chong

(2)

(3)

UG-32


The symbols defined below are used in the formulas of this paragraph: t P D S E

L

= minimum required thickness of head after forming, in. = internal design pressure (see UG-21), psi. = inside diameter of the head skirt; or inside length of the major axis of an ellipsoidal head; in. = maximum allowable stress value in tension. = 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. = inside spherical or crown radius, in.

Fion Zhang/ Charlie Chong

UG-32


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 vesselâ&#x20AC;&#x2122;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.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

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 UGâ&#x2C6;&#x2019;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.

Fion Zhang/ Charlie Chong

UG-32


2:1 ellipsoidal head: (d) Ellipsoidal Heads With ts /L â&#x2030;Ľ 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 â&#x2030;Ľ t. L = inside spherical or crown radius. The value of L for ellipsoidal heads shall be obtained from Table UG-37.

Fion Zhang/ Charlie Chong

UG-32


Non-2:1 ellipsoidal head; Appendix 1â&#x2C6;&#x2019;4 gives the following formulas for ellipsoidal heads with D/2h ratios other than 2:1.

Where K1D is the equivalent spherical radius

Fion Zhang/ Charlie Chong

UG-32


Non-2:1 ellipsoidal head; Appendix 1â&#x2C6;&#x2019;4 gives the following formulas for ellipsoidal heads with D/2h ratios other than 2:1.

Where K1D is the equivalent spherical radius 2:1 ellipsoidal head:

D = inside diameter of head skirt.

Fion Zhang/ Charlie Chong

UG-32


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. Fion Zhang/ Charlie Chong

UG-32


Non-2:1 ellipsoidal head; Appendix 1â&#x2C6;&#x2019;4 gives the following formulas for ellipsoidal heads with D/2h ratios other than 2:1.

Where K1D is the equivalent spherical radius Example: Standard 2:1 ellipsoidal head; h=D/4 D/2h = 2 ,K1 = 0.90#

D = inside diameter of head skirt. Fion Zhang/ Charlie Chong

UG-32


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

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-32


(e) Torispherical Heads With ts/L â&#x2030;Ľ 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).

Fion Zhang/ Charlie Chong

UG-32


ď Ž Knuckle radius is 6% of the inside crown radius ď Ž The inside crown radius equals the outside diameter of the skirt

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

UG-32


R=Do

r = 0.06Do

Fion Zhang/ Charlie Chong

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. Fion Zhang/ Charlie Chong

UG-32


Thickness Transition Between Hemispherical Head and Shell

Fion Zhang/ Charlie Chong

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:

Fion Zhang/ Charlie Chong

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 â&#x20AC;&#x153;Aâ&#x20AC;? 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.

Fion Zhang/ Charlie Chong

UG-32


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#

Fion Zhang/ Charlie Chong

UG-32


Fion Zhang/ Charlie Chong

UG-32


Example: For the same pressure, stress and, dimension values will be used for all heads. Letâ&#x20AC;&#x2122;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

Fion Zhang/ Charlie Chong

UG-32


Head

Equation

thickness

Ellipsoidal

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

Torispherical

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

Hemispherical

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

Fion Zhang/ Charlie Chong

UG-32


(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

Fion Zhang/ Charlie Chong

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 (Îą) = 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

Fion Zhang/ Charlie Chong

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:

Fion Zhang/ Charlie Chong

UG-32


Fion Zhang/ Charlie Chong

UG-32


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

Fion Zhang/ Charlie Chong

UG-32


UG-36 OPENINGS IN PRESSURE VESSELS.

Fion Zhang/ Charlie Chong

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: â&#x20AC;˘ 3 ½ in. diameter in vessel shells or heads 3/8 in. or less in thickness â&#x20AC;˘ 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

Fion Zhang/ Charlie Chong

UG-36


(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

Center to center > 2R1+2R2

Radius R1

Fion Zhang/ Charlie Chong

Radius R2

UG-36


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

Fion Zhang/ Charlie Chong

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: ď Ž Excess metal that is available in the shell or nozzle neck that is not required for pressure or to absorb other loads. ď Ž Reinforcement that is added to the shell or nozzle neck.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-37


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

Fion Zhang/ Charlie Chong

UG-37


ASME VIII, UG-37 The code uses the principle of the area replacement method

http://www.wermac.org/specials/branch_reinforced.html Fion Zhang/ Charlie Chong

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)

Fion Zhang/ Charlie Chong

UG-37


FIG. UG-37.1 NOMENCLATURE AND FORMULAS FOR REINFORCED OPENINGS

Fion Zhang/ Charlie Chong

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. Fion Zhang/ Charlie Chong

UG-37


Fion Zhang/ Charlie Chong

UG-37


Fion Zhang/ Charlie Chong

UG-37


If A1+A2+A41+A5â&#x2030;ĽA Opening is adequately reinforced

Fion Zhang/ Charlie Chong

UG-37


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

Fion Zhang/ Charlie Chong

UG-40


tn

A2

Smaller of 2.5t or 2.5tn+te

A4 A5

trn tr

A1

te

t

Larger of d or Rn+tn+t

Fion Zhang/ Charlie Chong

UG-40


Fion Zhang/ Charlie Chong

UG-40


Material available in pad A5

Spare area available in nozzle A2

tn Spare material available in shell A1

Material available in weld A4

Shell plate remove area (A)

te

Smaller of 2.5t or 2.5tn+te

t

Larger of d or Rn+tn+t

Fion Zhang/ Charlie Chong

UG-40


Fion Zhang/ Charlie Chong

UG-40


UG-84 CHARPY IMPACT TESTS

Fion Zhang/ Charlie Chong

UG-84


CHARPY IMPACT TESTS

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

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. Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-84


• (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)

Fion Zhang/ Charlie Chong

UG-84


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 1/16â&#x20AC;? 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.

Fion Zhang/ Charlie Chong

UG-84


Fion Zhang/ Charlie Chong

UG-84


Fion Zhang/ Charlie Chong

UG-84


GENERAL NOTES: a) Interpolation between yield strengths shown is permitted. b) The minimum impact energy for one specimen shall not be less than 2â &#x201E;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, SA334, 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).

Fion Zhang/ Charlie Chong

UG-84


Criteria for Acceptance & Retest. Figure UG-84.1. 1. The average energy of 3 specimen shall equal or exceed FIG. UG84.1 CHARPY V-NOTCH IMPACT TEST REQUIREMENTS 2. The minimum impact energy for one specimen shall not be less than 2â &#x201E;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.

Fion Zhang/ Charlie Chong

UG-84


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 â&#x2030;Ľ18f-lb. Minimum impact energy for one specimen 2/3 x 18 = 12 ft-lb. 1st Criteria for retest, 3 specimen average â&#x2030;Ľ 12 ft-lb.

Fion Zhang/ Charlie Chong

UG-84


UG-84 Testing

FIG. UG-84.1 & General Notes.

Accept

Satisfy UG-84(c)(6)

Reject

Fion Zhang/ Charlie Chong

Retest allowed with stringent requirement.

UG-84


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)

Fion Zhang/ Charlie Chong

UG-84


UG-99 STANDARD HYDROSTATIC TEST

Fion Zhang/ Charlie Chong

UG-99


STANDARD HYDROSTATIC TEST

Fion Zhang/ Charlie Chong

UG-99


UG-99 STANDARD HYDROSTATIC TEST 1999 addendum and later: Test Pressure in psi (MPa) = 1.3 MAWP Ă&#x2014; (Stest temp /Sdesign temp) Prior to 1999 addendum: Test Pressure in psi (MPa) = 1.5 MAWP Ă&#x2014; (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)

Fion Zhang/ Charlie Chong

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 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.

Fion Zhang/ Charlie Chong

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 â&#x20AC;&#x153;lethalâ&#x20AC;? substance.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-99


Metal temperature API 510 has a different rule for this, it recommends that the temperature be 10°F above for 2 in. (â&#x2030;¤50mm) thickness and under and 30°F above for over 2 in. (>50mm).

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-99


Example: Hydrostatic testing pressure Design pressure (MAWP) = 250 psi Design temperature = 750째F Material: carbon steel SA516-60 . S room = 15 000 psi . S 750째F = 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#

Fion Zhang/ Charlie Chong

UG-99


CAUTION: A small liquid relief valve set to 1â&#x2026;&#x201C; (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.

Fion Zhang/ Charlie Chong

UG-99


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.

Fion Zhang/ Charlie Chong

UG-99


UG-100 PNEUMATIC TEST.

Fion Zhang/ Charlie Chong

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: 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.

Fion Zhang/ Charlie Chong

UG-100


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 â&#x20AC;&#x153;lethalâ&#x20AC;? substance.

Fion Zhang/ Charlie Chong

UG-100


Fion Zhang/ Charlie Chong

UG-100


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

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

UG-100


“Test pressure divided by 1.1” is not MAWP! There is a LSR factor. Pneumatic test pressure = 1.1 x MAWP x LSR

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UG-100


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 1â &#x201E;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.

Fion Zhang/ Charlie Chong

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 1â &#x201E;4 in. (6 mm).

Fion Zhang/ Charlie Chong

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

Fion Zhang/ Charlie Chong

UG-100


UG-102 TEST GAGES

Fion Zhang/ Charlie Chong

UW-102


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 Fion Zhang/ Charlie Chong

UG-102


UG-102:

the gauge range be within 1½ and 4 times that of test pressure.

Applicable test pressure range: 37.7 ~100psi

Fion Zhang/ Charlie Chong

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.

middle third Applicable test range: 50~100psi

Fion Zhang/ Charlie Chong

UG-102


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: â&#x20AC;˘ Voltage transients in electrical systems. â&#x20AC;˘ Pressure transients in fluid systems. â&#x20AC;˘ Excess force or rapid movement in mechanical systems.

Fion Zhang/ Charlie Chong

UG-102


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.

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UW-102


UG-116 REQUIRED MARKING.

Fion Zhang/ Charlie Chong

UW-116


RT 1

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 UW11(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 2

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 3

UG-116(e3) “RT 3” when the complete vessel satisfies the spot radiography requirements of UW-11(b); or

RT 4

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.

Fion Zhang/ Charlie Chong

UW-116


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.

Fion Zhang/ Charlie Chong

UW-116


Fion Zhang/ Charlie Chong

UW-116


Fion Zhang/ Charlie Chong

UW-116


Fion Zhang/ Charlie Chong

UW-116


Required Marking â&#x20AC;˘ 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.

Fion Zhang/ Charlie Chong

UW-116


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.

Fion Zhang/ Charlie Chong

UW-116


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.

Fion Zhang/ Charlie Chong

UW-116


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. "PARTâ&#x20AC;&#x153;. b. Name of the Manufacturer. c. The manufacturer's serial number.

Fion Zhang/ Charlie Chong

UW-116


"RT 2" Complete vessel satisfies UW-11(a)(5) and UW11(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. Fion Zhang/ Charlie Chong

UW-116


Fion Zhang/ Charlie Chong

UW-116


Fion Zhang/ Charlie Chong

UW-116


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 (UW11(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)).

Fion Zhang/ Charlie Chong

UW-116


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)).

Fion Zhang/ Charlie Chong

UW-116


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).

Fion Zhang/ Charlie Chong

UW-116


Lethal service / thickness / unfired steam boiler.

RT 1

in vessels. (categories A, B, C, D)

RT 2 Optionally selected “E” from table UW-12(column a). Fion Zhang/ Charlie Chong

All butt welds

All category “A”

and “D” butt welds in vessel and categories “B” and “C” which intersect Category “A” shall meet the spot radiography requirement (UW-11(a) (5) (b)). UW-116


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 Fion Zhang/ Charlie Chong

UW-116


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 UG116(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 buttwelded 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 buttwelded 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]). http://www.nationalboard.org/PrintPage.aspx?NewsPageID=144 Fion Zhang/ Charlie Chong

UW-116


UG-119 Nameplates

Fion Zhang/ Charlie Chong

UW-119


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.

Fion Zhang/ Charlie Chong

UW-119


UG-120 Data Reports

Fion Zhang/ Charlie Chong

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.

Fion Zhang/ Charlie Chong

UW-120


Fion Zhang/ Charlie Chong

UW-120


UW-120 Fion Zhang/ Charlie Chong


UW-120 Fion Zhang/ Charlie Chong


Fion Zhang/ Charlie Chong

Asme viii ug ppt  
Read more
Read more
Similar to
Popular now
Just for you