ASTM F78-97

Standard Test Method for Calibration of Helium Leak Detectors by Use of Secondary Standards

SCOPE
1.1 This test method covers a procedure for calibrating a mass spectrometer-type helium leak detector with a series of commercially available calibrated leaks without need for recourse to a primary standard.
1.2 Leak detector parameters determined by this test method include:  
1.2.1 Minimum detectable signal, drift noise (8.5, with recorder; 8.6, without recorder),  
1.2.2 Response time,  
1.2.3 Minimum detectable leak rate, and  
1.2.4 Sensitivity.  
1.3 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Dec-1990
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaced By: ASTM F78-97(2002) - Standard Test Method for Calibration of Helium Leak Detectors by Use of Secondary Standards (Withdrawn 2008)
• Effective Date: 10-Dec-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact
ASTM International (www.astm.org) for the latest information.
Designation: F 78 – 97
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Calibration of Helium Leak Detectors by Use of Secondary
1
Standards
This standard is issued under the fixed designation F 78; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope under standard conditions specified as follows: (1) the inlet
pressure shall be 1 standard atmosphere 65 % (1016 5 kPa),
1.1 This test method covers a procedure for calibrating a
(2) the outlet pressure shall be less than 1 kPa (0.01 atm), and
mass spectrometer-type helium leak detector with a series of
(3) the temperature shall be 23 6 3°C.
commercially available calibrated leaks without need for
3.2 Definitions of Terms Specific to This Standard:
recourse to a primary standard.
3.2.1 response time—of a leak detector, for the purposes of
1.2 Leak detector parameters determined by this test method
this test method, a measure of the speed of response of the
include:
detector to an incoming helium sample.
1.2.1 Minimum detectable signal, drift noise (8.5, with
3.2.1.1 Discussion—In this test method the cleanup time
recorder; 8.6, without recorder),
and response time are assumed to be equal.
1.2.2 Response time,
3.2.2 sensitivity—of a leak detector, for the purposes of this
1.2.3 Minimum detectable leak rate, and
test method, the ratio of the change in the output signal to the
1.2.4 Sensitivity.
applied helium leak rate.
1.3 This standard does not purport to address the safety
3.3 Other terms used in this test method are defined in
concerns, if any, associated with its use. It is the responsibility
Definitions E 425.
of the user of this standard to establish appropriate safety and
health practices and determine the applicability of regulatory
4. Summary of Test Method
limitations prior to use.
4.1 At least three calibrated leaks are tested on a helium leak
2. Referenced Documents
detector, and a correlation is obtained between the output
indication of the leak detector and the leak rate of the calibrated
2.1 ASTM Standards:
2
leaks. These readings are used to plot a calibration line from
E 1 Specification for ASTM Thermometers
3
which intermediate values, within specified limits, may be
E 425 Definitions of Terms Relating to Leak Testing
read.
3. Terminology
5. Interferences
3.1 Definitions:
3.1.1 calibrated leak—in leak detection, a device that per- 5.1 Certain materials, particularly organic compounds, will
mits leakage through it at a specified rate, of a specific gas, entrap or hold helium tracer gas. Use of such materials in
under specific conditions, with the downstream side of the
connections between the calibrated leak and the leak should be
device exposed to a pressure sufficiently low to have negligible minimized to avoid erroneous results. (If the net output
effect on the leak rate.
readings from any calibrated leak consistently lie outside the
3.1.2 minimum detectable signal—in leak detection, the established limits, the leak should be returned to the supplier
smallest unambiguous output signal that can be derived from a
for a recalibration check.)
given particular leak detector. Units are detector scale divi- 5.2 The background reading, B, should be at most one
sions.
quarter of the output reading, A. If the value of B approaches
3.1.2.1 Discussion—The minimum detectable signal is de- that of A, the accuracy of the determination of N will suffer (see
termined by the noise present in, and drift of, the output signal.
9.3.1).
3.1.3 standard leak rate—in leak detection, the rate of flow
6. Apparatus
of atmospheric air of dewpoint less than − 25°C through a leak
6.1 Calibrated Leaks—At least three commercial devices
1 incorporating leaks, one having a leak rate of approximately
This test method is under the jurisdiction of ASTM Committee F-1 on
−9 3 −1 −10 3 −1
Electronic and is the direct responsibility of Subcommittee F 01.03 on Metallic 10 atm·cm ·s (10 Pa·m ·s ), a second having a leak
−8 −7 3 −1 −9
Materials.
value in the nominal range from 10 to 10 atm·cm ·s (10
Current edition approved Dec. 10, 1997. Published March 1998. Originally −8 3 −1
to 10 Pa·m ·s ), and the third having a leak rate of
e1
published as F 78 – 67 T. Last previous edition F 78 – 79 (l991) .
−6 3 −1 −7 3 −1
2
approximately 10 atm·cm ·s (10 Pa·m ·s ).
Annual Book of ASTM Standards, Vol 14.03.
3
Discontinued, see 1991 Annual Book of ASTM Standards, Vol 03.03. 6.1.1 The calibrated leaks shall be obtained from at least
1

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