ASME BPVC.IX-2025

ASME BPVC.IX-2025 ARTICLE 5
TESTS, INSPECTION, AND MARKING
HG-500 PROOF TESTS TO ESTABLISH DESIGN
PRESSURE
HG-501 General
(a) The design pressure for pressure parts of boilers for
which the strength cannot be computed with a satisfactory
assurance of accuracy shall be established in accordance
with the requirements of this paragraph, using one of the
test procedures applicable to the type of loading and to the
material used in its construction.
(b) The tests in these paragraphs may be used only for
the purpose of establishing the design pressure of those
elements or component parts for which the thickness
cannot be determined by means of the design rules
given in the Code. The design pressure of all other
elements or component parts shall not be greater than
that determined by means of the applicable design rules.
HG-501.1 Types of Tests. Provision is made for two
types of tests for determining the internal design
pressure:
(a) tests based on yielding of the part to be tested; these
tests are limited to materials with a ratio of minimum
specified yield to minimum specified ultimate strength
of 0.625 or less. If a proof-tested part shows no evidence
of permanent yielding per HG-502.1 and HG-502.2, it may
be marked with the Certification Mark.
(b) tests based on bursting of the part. The Certification
Mark shall not be applied on the part proof tested under
the burst-test provisions.
HG-501.2 Retests. A retest shall be allowed on a
duplicate pressure part if errors or irregularities are
obvious in the test results.
HG-501.3 Precautions. Safety of testing personnel
should be given serious consideration when conducting
proof tests, and particular care should be taken during
the conducting of bursting tests per HG-502.3.
HG-501.4 Pressure Application.
(a) Previously Applied. The pressure parts for which the
design pressure is to be established shall not previously
have been subjected to a pressure greater than 11∕2 times
the desired or anticipated design pressure.
(b) Application. In the procedures given in HG-502.1 for
the strain measurement test and HG-502.2 for the displacement
measurement test, the hydrostatic pressure
in the pressure part shall be increased gradually until
approximately one-half the anticipated design pressure
is reached. Thereafter, the test pressure shall be increased
in steps of approximately one-tenth or less of the anticipated
design pressure until the pressure required by the
test procedure is reached. The pressure shall be held
stationary at the end of each increment for a sufficient
time to allow the observations required by the test procedure
to be made and shall be released to zero to permit
determination of any permanent strain or displacement
after any pressure increment that indicates an increase in
strain or displacement over the previous equal pressure
increment.
HG-501.5 Critical Areas. As a check that the
measurements are being taken on the most critical
areas, the Inspector may require a lime wash or other
brittle coating to be applied on all areas of probable
high stress concentrations in the test procedures given
in HG-502.1 and HG-502.2. The surfaces shall be suitably
clean before the coating is applied in order to obtain satisfactory
adhesion. The technique shall be suited to the
coating material.
NOTE: Strains should be measured as they apply to membrane
stresses. In regard to bending stresses it is recognized that high
localized and secondary stresses may exist in pressure parts
designed and fabricated in accordance with these rules.
Insofar as practical, design rules for details have been
written to hold such stresses at a safe level consistent with
experience.
HG-501.6 Yield Strength and Tensile Strength.
For proof tests based on yielding, HG-502.1 and
HG-502.2, the yield strength (or yield point for those materials
that exhibit that type of yield behavior indicated by a
“sharp-kneed” portion of the stress–strain diagram) of the
material in the part tested, shall be determined in accordance
with the method prescribed in the applicable material
specification and as described in ASTM E8, Tension
Testing of Metallic Materials. For proof tests based on
bursting, HG-502.3, the tensile strength instead of the
yield strength of the material in the part tested shall
be similarly determined.
ASME BPVC.IV-2025
37

electrode, stranded: a composite filler metal electrode
consisting of stranded wires which may mechanically
enclose materials to improve properties, stabilize the
arc, or provide shielding.
electrode, tungsten: a nonfiller metal electrode used in arc
welding, arc cutting, and plasma spraying, made principally
of tungsten.
electrofusion (EF): fusing accomplished by heating polyethylene
materials above their melting points using electric
elements within a confined space, producing
temperatures and pressures necessary to achieve coalescence
of the molten polyethylene materials during the
cooling phase. Some of the more common terms relating
to EF are defined in ASTM F1290 and ASTM F412.
electrofusion manufacturer: the manufacturer of electrofusion
fittings.
face feed: the application of filler metal to the face side of a
joint.
filler metal: the metal or alloy to be added in making a
welded, brazed, or soldered joint.
filler metal, brazing: the metal or alloy used as a filler metal
in brazing, which has a liquidus above 840°F (450 °C) and
below the solidus of the base metal.
filler metal, powder: filler metal in particle form.
filler metal, supplemental: in electroslag welding or in a
welding process in which there is an arc between one
or more consumable electrodes and the workpiece, a
powder, solid, or composite material that is introduced
into the weld other than the consumable electrode(s).
fillet weld: a weld of approximately triangular cross
section joining two surfaces approximately at right
angles to each other in a lap joint, tee joint, or corner joint.
flaw: an undesirable discontinuity. See also defect.
flux (welding or brazing): a material used to dissolve,
prevent, or facilitate the removal of oxides or other undesirable
surface substances. It may act to stabilize the arc,
shield the molten pool, and may or may not evolve
shielding gas by decomposition.
flux cover: metal bath dip brazing and dip soldering. A layer
of molten flux over the molten filler metal bath.
flux, active (SAW): a flux from which the amount of
elements deposited in the weld metal is dependent
upon the welding parameters, primarily arc voltage.
flux, alloy (SAW): a flux which provides alloying elements
in the weld metal deposit.
flux, neutral (SAW): a flux which will not cause a significant
change in the weld metal composition when there is a
large change in the arc voltage.
forehand welding: a welding technique in which the
welding torch or gun is directed toward the progress
of welding.
frequency: the completed number of cycles which the oscillating
head makes in 1 min or other specified time increment.
frictional resistance in the butt-fusing machine: forceopposing
movement due to friction in the mechanism
of the fusing machine.
fuel gas: a gas such as acetylene, natural gas, hydrogen,
propane, stabilized methylacetylene propadiene, and
other fuels normally used with oxygen in one of the
oxyfuel processes and for heating.
fused spray deposit (thermal spraying): a self-fluxing
thermal spray deposit which is subsequently heated to
coalescence within itself and with the substrate.
fusing (plastic fusing): the process of producing a fusion
joint. Butt, manual butt, electrofusion, and sidewall are the
fusing processes addressed in this Code.
fusing gauge pressure: the hydraulic gauge pressure to be
observed by the fusing operator when butt fusing or sidewall
fusing polyethylene (PE) piping. This is the sum of the
theoretical fusing pressure plus the drag pressure.
fusing operator: person trained and qualified to carry out
fusing of polyethylene (PE) pipes and/or fittings using a
butt-fusing or sidewall-fusing procedure or electrofusion
procedure with applicable equipment.
fusing procedure specification: a document providing in
detail the required variables for the fusing process to
ensure repeatability in the fusing procedure. This
generic term includes fusing procedure specifications
qualified by testing (FPS), as well as standard fusing procedure
specifications (SFPS) or manufacturer qualified electrofusion
procedure specifications (MEFPS).
fusion (fusion welding): the melting together of filler metal
and base metal, or of base metal only, to produce a weld.
fusion (plastic fusing): the portion of the fusing process
involving the coalescence of two plastic members by
the combination of controlled heating and the application
of pressure approximately normal to the interface
between them; the joint produced by plastic fusing.
fusion face: a surface of the base metal that will be melted
during welding.
fusion interfacial pressure: the interfacial pressure applied
during the fusion phase of the fusing process.
fusion line: a non-standard term for weld interface.
gas backing: see backing gas.
globular transfer (arc welding): a type of metal transfer in
which molten filler metal is transferred across the arc in
large droplets.
groove weld: a weld made in a groove formed within a
single member or in the groove between two members
to be joined. The standard types of groove weld are as
follows:

crack: a fracture-type discontinuity characterized by a
sharp tip and high ratio of length and width to
opening displacement.
creep strength enhanced ferritic alloys (CSEF’s): a family of
ferritic steels whose creep temperature strength is
enhanced by the creation of a precise condition of microstructure,
specifically martensite or bainite, which is stabilized
during tempering by controlled precipitation of
temper-resistant carbides, carbo-nitrides, or other
stable and/or meta-stable phases.
data acquisition record: a detailed, permanent record of
variables applicable to the fusing process, such as buttfusion
pressure, electrofusion voltage, and cycle cooldown
times, along with the measured heater surface
temperature, employee information, butt-fusing or electrofusion
machine information, pipe information, date,
and time for each joint made.
defect: a discontinuity or discontinuities that by nature or
accumulated effect (for example, total crack length)
render a part or product unable to meet minimum applicable
acceptance standards or specifications. This term
designates rejectability. See also discontinuity and flaw.
direct current electrode negative (DCEN): the arrangement
of direct current arc welding leads in which the electrode
is the negative pole and the workpiece is the positive pole
of the welding arc.
direct current electrode positive (DCEP): the arrangement
of direct current arc welding leads in which the electrode
is the positive pole and the workpiece is the negative pole
of the welding arc.
discontinuity: an interruption of the typical structure of a
material, such as a lack of homogeneity in its mechanical,
metallurgical, or physical characteristics. A discontinuity
is not necessarily a defect. See also defect and flaw.
double-welded joint: a joint that is welded from both sides.
double-welded lap joint: a lap joint in which the overlapped
edges of the members to be joined are welded along the
edges of both members.
drag pressure: the pressure required to overcome the drag
resistance and frictional resistance in the butt-fusing
machine and keep the carriage moving at its slowest
speed.
drag resistance: force-opposing movement of the movable
clamp of the butt-fusing machine due to the weight of the
pipe.
dwell: the time during which the energy source pauses at
any point in each oscillation.
electrode, arc welding: a component of the welding circuit
through which current is conducted.
electrode, bare: a filler metal electrode that has been
produced as a wire, strip, or bar with no coating or
covering other than that incidental to its manufacture
or provided for purposes of preservation, feeding, or electrical
contact.
electrode, carbon: a nonfiller material electrode used in arc
welding and cutting, consisting of a carbon or graphite rod,
which may be coated with copper or other materials.
electrode, composite: a generic term of multicomponent
filler metal electrodes in various physical forms, such
as stranded wires, tubes, and covered electrodes.
electrode, covered: a composite filler metal electrode
consisting of a core of a bare electrode or metal-cored
electrode to which a covering sufficient to provide a
slag layer on the weld metal has been applied. The
covering may contain materials providing such functions
as shielding from the atmosphere, deoxidation, and arc
stabilization, and can serve as a source of metallic additions
to the weld.
electrode, electroslag welding: a filler metal component of
the welding circuit through which current is conducted
between the electrode guiding member and the molten
slag.
NOTE: Bare electrodes and composite electrodes as defined
under arc welding electrode are used for electroslag welding.
A consumable guide may also be used as part of the electroslag
welding electrode system.
electrode, emissive: a filler metal electrode consisting of a
core of a bare electrode or a composite electrode to which
a very light coating has been applied to produce a stable
arc.
electrode, flux-cored: a composite filler metal electrode
consisting of a metal tube or other hollow configuration
containing ingredients to provide such functions as
shielding atmosphere, deoxidation, arc stabilization,
and slag formation. Alloying materials may be included
in the core. External shielding may or may not be used.
electrode, lightly coated: a filler metal electrode consisting
of a metal wire with a light coating applied subsequent to
the drawing operation, primarily for stabilizing the arc.
electrode, metal: a filler or nonfiller metal electrode used in
arc welding and cutting that consists of a metal wire or rod
that has been manufactured by any method and that is
either bare or covered.
electrode, metal-cored: a composite filler metal electrode
consisting of a metal tube or other hollow configuration
containing alloying ingredients. Minor amounts of ingredients
providing such functions as arc stabilization and
fluxing of oxides may be included. External shielding
gas may or may not be used.
electrode, resistance welding: the part of a resistance
welding machine through which the welding current
and, in most cases, force are applied directly to the workpiece.
The electrode may be in the form of a rotating wheel,
rotating roll, bar, cylinder, plate, clamp, chuck, or modification
thereof.
ASME BPVC.IX-2025