Testing and Stamping

8/10/2019 Testing and Stamping

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ASME Section VIII, Div.1

Pressure Test ingand

Code Stamp ing


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Topics

Requirements for Pressure Testing

Hydrostatic Testing

Pneumatic Testing

Test Gauge

Stamping


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Requirements

forPressure Testing


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Why Test?

Detect gross defects in

design and fabrication


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What Must Be Pressure Tested?

Completed vessels, fabricated to the

ASME Code, at the required pressureand temperature


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Hydrostatic Testing


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Test Temperature

The recommended minimum metal

temperature of 30 oF above the

design minimum design metal

temperature (MDMT) and not over

120

o

F


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HydroTest Pressure

d

tp

S

SMAWPT )3.1(

Tp = Test Pressure

MAWP= Maximum Allowable Working Pressure

St = Material stress value at test temperature

Sd = Material stress value at design temperature


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Exceptions

Vacuum Service

Combination Units

Enameled VesselsCast Iron Vessels


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Combination Units

When operated independently test

as separate vessel

Example: Heat Exchangers


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Enameled Vessels

Test pressure shall be equal to

but need not be above the

vessel MAWP


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Cast Iron Vessels

MAWP < 30 psi:

Test pressure must be 2.5 x MAWP

and 30 psi:

Test pressure must be 2 x MAWP


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Pneumatic Test Pressure

d

tp

S

Sx10.1MAWPxT

Tp = Test Pressure

MAWP= Maximum Allowable Working Pressure

St = Material stress value at test temperature

Sd = Material Stress value at Design temperature


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Test Procedure

1. Gradually increase pressure to

about test pressure

2. Thereafter, increase the pressure atan interval equal to 1/10 of the test

pressure until the test pressure has

been reached

Assure that UW-50 has been compliedpriorto

pneumatic testing


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Witness Pressure Test

Authorized Inspector shall

witness pressure tests for all

vessels being U stamped,except multiple vessels

fabricated to UG-90(c)(2)


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UG-102: Test Gauges

Connected directly to the vessel

Visible to the Operator

Graduated at a range double thetest pressure, but in no case morethan 4 times or less than 1-1/2 timesthe test pressure

Calibrated against a deadweighttester or master gauge


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Stamping


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UG-118: Methods of Marking

Marking may be directly on the vessel

or on a nameplate

Minimum letter size requirements for

either direct stamping or nameplate

A nameplate is required on

Ferrous materials less than 1/4 thick

Non-ferrous materials less than thick


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Symbol Stamping

Code stamps may be applied on the

vessel or on a nameplate attached to

the vessel, prior to hydrostatic testTest procedure must be documented

in the Manufacturers program

The Authorized Inspector must haveaccepted the test procedure


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Type of Construction

Arc/Gas Welded - W

Brazed - B

Pressure Welded - PResistance Welded - RES


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Special Services

Lethal Services L

Unfired Steam Boiler UB

Direct Fired Vessels DFNon-stationary NPV

Pressure Vessels

Letters are located under the U Codesymbol stamp


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Degree of Radiography

Full Radiography RT-1

UW-11 (a)(5)(b) RT-2

Spot Radiography RT-3When RT-1, RT-2 RT-4

or RT-3 does not apply


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Postweld Heat Treatment

Entire vessel heat treated HT

Partial heat treatment PHT


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Vessel Parts

The word part must be stamped

under the U Code stamp symbol

The Manufacturers name, precededby Certified by, and the serial

numbers are the only identification

required


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Code Stamp

Code Symbol

The U symbol stamp is for

a Manufacturer who

fabricates complete

pressure vessels in the shop

or field

The holder of a U stampmay also make vessel parts

U


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Code Stamping


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Code Stamp

The UM Code

Symbol is applied to

pressure vessels thatare built to the

requirements of U-1(j)

UM


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Code Stamp

The UV symbol is

used for pressure

relief devices thatmeet Section VIII,

Div. 1 requirements.

UV


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Questions?

Pressure Testing & CodeStamping

Testing and Stamping

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