510 Sec8 div1 Flashcards
Vessels covered by this Code pressure from
15 PSI to 3000PSI
Vessels excluded from this Code
Less Than 6” in Diameter and Containing water with one of the following:
- A Design pressure less than 300 PSI
- A Desing temperature less than 210 Degrees F
Welding Materials when received may be accepted if???
It is tagged or marked by the material specification
Minimum Thickness permitted for shells and heads shall be
1/16 In. Exclusive of Corrosion Allowance
Minimum Thickness of shells and heads of unfired steam boilers shall be
1/4 In. Exclusive of any Corrosion Allowance
Minimum thickness of shells and heads used in compressed air, steam, and water service
3/32 in.
Plate Under Tolerance actual thickness less than the design thickness shall not be used unless
The difference in thicknesses is less than the smaller of 0.01in. or 6% of the design thickness.
Impact testing is not mandatory for pressure vessel materials that satisfy all of the following requirements:
- The material shall be limited to P-No.1, Gr. No. 1 or 2
-The thickness shall not exceed 1/2in. for materials in curve A. and 1in. for materials listed in Curve B, C, D
-The completed vessel shall be hydrostatically tested or alternatively vessel may be Pneumatically tested.
-Desing Temp no warmer than 650 Degrees F.
-Thermal & Mechanical shock loadings are not a controlling design requirement.
-cyclical loading is not a controlling design requirement.
Opening in Pressure Vessel
For ID Equal to or Less than 60” the max opening =
1/2 ID but not exceed 20”
Impact test procedures and apparatus shall conform to ?
paragraphs of SA 370 at ASME II
Opening in Pressure Vessel
For ID Greater than 60”, the max opening =
1/3 ID but not exceed 40”
Impact test temperature shall no be warmer than?
MDMT
Each set of impact test specimens shall consist of how many specimens?
3
Test specimens shall be of which type?
V-Notch Type
Hydrostatic Test Pressure Formula
1.3 X MAWP X S test / S Design or 1.3 X MAWP X LSR (LSR - Lowest stress ratio = S test/S design
Hydrostatic Testing inspection shall be made of?
all joints and connections
Hydrostatic Testing inspection shall be made at what pressure
Not less than the hydrostatic test pressure divided by 1.3
Recommended that metal temperature during hydrostatic test be maintained at what temperature?
at least 30 degrees F above the minimum design metal temperature but need not exceed 120 degrees F to minimize the risk of brittle fracture.
Can welds of vessels be painted or coated prior to the pressure test?
Can’t be painted or coated either internally or externally.
Hydrostatic test pressure shall be reduced to what value?
A value equal to the test pressure divided by 1.3 to inspection
Pneumatic test may be used in lieu of the hydrostatic test if?
- Designed and/or supported that they cannot safely be filled with water
- Not readily dried, that are to be used in services where traces of the testing liquid cannot be tolerated.
Pneumatic test pressure Formula
1.1 X MAWP X Stest/Sdesign
Pneumatic test pressure shall be gradually increased to what pressure?
Gradually increased to not more than 1/2 of the test pressure. Thereafter, the test pressure shall be increased in steps of approximately 1/10 of the test pressure until the required test pressure has been reached
Where shall the indicating gauges be connected to?
Directly to the vessel or with a pressure line that does not include valves.
Indicating gage shall be provided and located where?
So that the gage is visible to the operator for the duration of the test.
For Large vessels, what kinds of gages is recommended for use
Recording gage to be used in addition to indicating gages
What shall the indicating pressure gage range be
1 1/2 to 4 times the test pressure
Required Marking for after RT examination been performed.
RT1 =
Full Radiography (E=1)
Required Marking for after RT examination been performed.
RT2 =
Spot RT, UW-11(a)(5)(-b) requirements have been met (E=1)
Required Marking for after RT examination been performed.
RT3 =
Spot RT, UW-11(a)(5)(-b) requirements have not been met (E=.85)
Required Marking for after RT examination been performed.
RT4 =
When only part of the complete vessel has satisfied the radiographic requirement where none of the markings RT1,2,3 are applicable. “Can’t identify E”
Required Marking for after RT or UT examination been performed.
HT=
when the complete vessel has been post weld heat treated
Required Marking for after RT or UT examination been performed.
PHT=
When only part of the vessel has been post weld heat treated.
What service restrictions do vessels that contain lethal substances liquid or gaseous have?
-All butt welded joints shall be fully radiographed (RT1)
-All joints of Category A shall be type no.1
-All category B and C joints shall be type No.1 or No.2
-When fabricated of carbon or low alloy steel, vessels shall be post weld heat treated
What is lethal substances
Gases or liquids of such a nature that a very small amount of mixed or unmixed with air is dangerous to life when inhaled.
Welded Joint Categories
Category A =
Longitudinal
Welded Joint Categories
Category B =
Circumferential
Welded Joint Categories
Category C =
Flanges
Welded Joint Categories
Category D =
Opening
Welded Joint Categories
A circumferential weld connecting hemispherical heads to shells
Category A - Longitudinal
Joint Efficiency by weld type and weld category
Type No.1 =
Butt Joints welded from both sides, or one side without a permanent backing strip that can be verified full penetration and fusion from inside.
Joint Efficiency by weld type and weld category
Type No.2 =
Butt Joints welded from one side only with a permanent backing strip
Joint Efficiency by weld type and weld category
Type No.3 =
Butt joints welded from one side only without permanent backing strip and cannot be verified full penetration and fusion from inside.
Lowest permissible temperatures for welding?
-No welding to be done when temperature of the base metal is lower than 0 Degrees F
-At temperatures between 32 degrees F and 0 degrees F, surface areas within 3in. of the weld is to be heated to a warm to the hand (Estimated Above 60Degrees F) before welding
Which table in Asme section VIII Div 2 can you find the Alignment tolerance by Thickness, and weld joint category
UW-33
Why is PWHT used?
To reduce residual stress
Which section in Asme section VIII Div 1 does design thickness formulas start?
UG-27
What is Joint Efficiency
a penalty applied to the allowable stress in the design formulas. Simply put “ The better the joint is, the higher the efficiency, up to a possible value of 1.0 being the equivalent of a seamless plate.
How is joint efficiency increased?
By type of joint and the amount of NDE this is performed.
Which Table in Asme section VIII Div 1 can you find the joint efficiency?
UW-12
When RT2 Stamping is used, the requirements of UW-11(a)(5)(-B) must be met. What does this mean?
The vessel would have to be completely spot radiographed and have intersections where category B or C butt welds meet category A welds radiographed as well. “ More RT Performed”
What are the 5 type of formed heads of a pressure vessel listed in Asme Section VIII-1?
Ellipsoidal
Torispherical
Hemispherical
conical
toriconical
Formula of Ellipsoidal Head Thickness Calculation
t=P(D)/2(S)(E)-o.2(P)
Formula of Hemispherical Head Thickness Calculation
t=P(L)/2(S)(E)-0.2(P)
Variables for Formula of Ellipsoidal Head Thickness Calculation
t=P(D)/2(S)(E)-o.2(P)
P= Internal design Pressure
D= Inside diameter of the head skirt
S=maximum allowable stress value
E= Lowest efficiency of any joint in the head
t= minimum required thickness of head after forming
Formula of Hemispherical Head Thickness Calculation
t=P(L)/2(S)(E)-0.2(P)
P= Internal design Pressure
L= Inside Spherical or crown radius
S=maximum allowable stress value
E= Lowest efficiency of any joint in the head
t= minimum required thickness of head after forming
What is MAWP for a Vessel
The maximum pressure permissible at the top of the vessel in its normal operating position at the designated coincident temp specified for that pressure
What is MAWP for a vessel part.
It is the maximum internal or external pressure including the static head
