semi合集-English.pdf - 第3740页
SEMI F1-96 © SEMI 19 90, 1996 3 5.18 system — An integrated structu r e of components and su bsystems capable of perf or ming , in aggregate, one or m ore specific functions. F o r the purpos e of this specification, a s…
SEMI F1-96 © SEMI 1990, 1996 2
with other pieces or components. The typical
components referred to by this specification are valves,
fittings, regulators, pressure gauges, pressure and flow
sensors, and tubing welded to fittings.
5.3 design pressure — Of a system or subsystem, the
pressure at the most severe condition of internal and
external pressure expected during normal service. The
maximum pressure expected in any portion of a system
or subsystem is typically determined by the maximum
adjustable setting of the last pressure regulator that
supplies it, the supply pressure to the regulator, or the
actuation pressure of any relief device incorporated.
5.4 high-purity — Of a system, subsystem, or
component used for the control of chemicals (gases or
liquids), designed and constructed in such a manner that
it does not introduce significant impurities, particulate
or molecular, into the flow stream it controls or
regulates.
NOTE: Such systems, subsystems, or components are
designed and constructed such that, if an impurity is
introduced into the flow path, it can be readily purged to an
insignificant level.
5.5 leak — A path (or paths) in a sealed system that
will pass tracer gas when a pressure differential or
diffusion path exists. There are two leak mechanisms: a
mechanical passage and a material through which gas
can diffuse or permeate. A leak may have both
mechanisms operating in parallel.
5.6 leakage, inboard — Leakage from outside to
inside occurring when the internal pressure is less than
the external pressure acting on a component. Inboard
leakage is typically determined by introducing a tracer
gas around the exterior of the piping system or
component under test.
NOTE: Inboard leak tests are easier tests to conduct to high
sensitivity levels, but are typically not indicative of
pressurized operating conditions. It is difficult to correlate an
inboard leak test to the performance of a component,
subsystem, or system when under internal pressure. Also, the
internal collapsing forces created by external pressure may
mask leaks which may exist under pressurized operating
conditions.
5.7 leakage, internal — Leakage occurring within a
component across a flow barrier, such as the seat of a
closed valve.
5.8 leakage, outboard — Leakage from inside to
outside occurring when the internal pressure is greater
than the external pressure acting on a component.
Outboard leakage is typically determined by
introducing a tracer gas into the interior of the piping
system or component under test.
5.9 may — A term indicating that a provision is
neither required nor prohibited by this specification.
5.10 measured leak rate — The rate of leakage of a
given component, subsystem, or system measured
under specific conditions and employing a tracer gas.
NOTE: When testing with high-pressure 100% helium on a
mass spectrometer leak detector, measured leak rates must be
converted to equivalent standard leak rates.
5.11 qualification test — A test conducted on samples
of production articles manufactured to a single design
to establish the performance rating of a product. The
tests are extensive and closely controlled and
completely analyze the characteristics of a component
for use in a high-purity installation.
5.12 rated pressure — The manufacturer’s
recommended maximum allowable operating pressure
at the manufacturer’s rated temperature.
5.13 shall — A term indicating that a provision is a
requirement of this specification.
5.14 should — A term indicating that a provision is
recommended as good practice but is not a requirement
of this specification.
5.15 shutoff valve — A valve designed for, and
capable of, positive closure to prevent flow within a
system. Typical shutoff valves include manually
actuated, power-actuated, or spring-actuated, fail-safe
shutoff valves. Generally excluded are self-actuated
valves such as check valves, pressure regulators, flow
controllers, and other devices not intended to provide
positive shutoff.
5.16 standard leak rate — The flow of helium at
21.1°C (70°F) and 101.3 kPa (1 atm) through a leak
when the partial pressure of helium on the high side is
101.3 kPa and the partial pressure on the low side is
below 133 Pa (1 torr).
NOTE: Express leak rates in kiloPascal-liters per second
(kPa-L/sec). Calculate the standard leak rate of helium from
the measured leak rate by multiplying by the ratio of 101.3
kPa to the partial pressure of helium, as follows:
Standard
=
101.3 kPa(1 atm)
×
measured leak rate
actual He partial pressure
≠
ú
5.17 subsystem — An assembly of two or more
components manufactured as a single entity. A
subsystem must be combined with one or more
additional components or subsystems to form a
complete system. The typical subsystems referred to by
this specification are gas source manifolds, gas
distribution manifolds, and gas control manifolds
within the process equipment.
SEMI F1-96 © SEMI 1990, 19963
5.18 system — An integrated structure of components
and subsystems capable of performing, in aggregate,
one or more specific functions. For the purpose of this
specification, a system includes the gas source
manifold, its connection to the gas source, the
distribution piping, and the gas control manifold within
the process equipment.
6 Ordering Information
Orders for equipment or services requiring leak testing
in accordance with this specification shall include:
a. This specification number and date of issue.
b. Acceptance test requirements and applicable test
paragraphs of this specification for the specific
product being purchased.
c. Qualification test requirements, if any, and
applicable test paragraphs of this specification for
the specific product being purchased.
d. The design pressure to be used for internal and
outboard leakage testing of systems, subsystems, or
components.
e. Whether certification of the qualification or
acceptance tests and a report of test results is
required.
7 Requirements
7.1 Personnel Qualifications — Personnel performing
tests in accordance with this specification shall have
suitable training and experience. Such personnel
should, as a minimum:
a. be trained and experienced in the use of mass
spectrometer leak detectors,
b. be familiar with the use of the ASTM test methods
referenced by this specification, and
c. be familiar with the operation and calibration of the
specific equipment used in performing the tests.
7.2 Tests
7.2.1 Prior to initial operation, test each component,
subsystem, and system in accordance with this
specification.
7.2.2 If repairs or additions are made after the leakage
tests, retest the affected portions of the component,
subsystem, or system.
7.3 Test Conditions
7.3.1 All joints, including welds, shall be uninsulated,
unpainted, and exposed for examination during the test.
7.3.2 Isolate portions of a system that are not being
tested during the test.
7.3.3 Tracer gas pressure shall not exceed the
manufacturer’s pressure rating.
7.3.4 Conduct leakage tests at a temperature between
18°C (64°F) and 26°C (78°F).
SEMI F1-96 © SEMI 1990, 1996 4
7.4 Leak Rate Limits
Table 1
Direction Component Component Subsystem System
kPa - L/sec atm - cc/sec kPa - L/sec atm - cc/sec kPa - L/sec atm - cc/sec
Inboard 10
-10
10
-9
10
-9
10
-8
10
-10
(per point) 10
-9
Internal 10
-10
10
-9
10
-10
10
-9
10
-10
10
-9
Outboard 10
-10
10
-9
10
-9
10
-8
1 ppm
(or 1 ppm increase in atmospheric
concentration if by probe method)
1 ppm increase in atmospheric
concentration
NOTES:
a. The internal leakage specifications apply only if the test object is rated for positive closure.
b. The internal leakage specification applies to each positive closure. If positive shutoff devices are in parallel, the specification applies
to the parallel devices as a group.
c. When piping systems or components employ polymeric seals, the internal and outboard leak rates specified above shall be modified by
multiplying the stated values by 100.
d. When new construction projects preclude measurement of outboard leakage at the leak rates specified above, the outboard leakage
limits shall be modified by multiplying the stated values by 100.
8 Test Methods
8.1 Dangers
8.1.1 Testing of systems, subsystems, or components with high pressure gas could cause explosive rupture of these
items, with the resulting fragmentation causing death or serious injury. In addition, if a component of the system
under test were to fail, an unrestricted supply of tracer gas could cause pressurization and rupture of the test
enclosure. Such testing shall not be performed without shielding that will protect the operator and other personnel in
the event of equipment failure. The source of tracer gas should be provided with a suitable device that will limit or
shut off the flow in the event of component rupture.
8.1.2 Some elements of a piping system may not be designed for pressurization. Pressurization of such system
elements could cause explosive rupture, with the resulting fragmentation causing death or serious injury. Such
elements shall not be tested in a manner inconsistent with the manufacturer’s specifications. Valves used to isolate
these elements of systems must be rated for higher pressure than the proposed test pressure.
8.1.3 Some components may be designed for closure only in one direction or only under pressure or vacuum.
Testing of such components in a manner other than that for which they are designed could cause explosive rupture,
with the resulting fragmentation causing death or serious injury. Such components shall not be tested in a manner
inconsistent with the manufacturer’s specifications.
8.2 Tracer Gas — (Unless otherwise specified in Sections 8.4 through 8.6.)
8.2.1 For those tests in which the test object is enclosed in or sprayed with tracer gas, 100% helium.
8.2.2 For those tests in which the test object is pressurized with tracer gas, 101.3 kPa (1 atm) of helium plus
nitrogen to pressurize to the design pressure.
8.2.3 The use of helium with a purity level of less than 100 ppb total contaminants and filtered at point of use to
less than 0.1 µm is required.
8.2.4 Inboard tests are performed at one atmosphere.
8.2.5 Internal and outboard tests are performed at the design pressure.
8.3 The use of a dry, oil-free helium mass spectrometer leak detector is recommended to prevent hydrocarbon
contamination of the piping system or component during inboard and internal leak testing.