USP 1207

Deterministic

Leak Test

Technologies

Package

Content

Requirements

Package

Requirements

Leak Detection Limit

Measurement Outcome and

Data Analysis

Effect of

Method

on Package

Test Time

Order of

Magnitude

Electrical conductivity and

capacitance (high-voltage

leak detection)

Liquid (with no combustion

risk) must be more electrically conductive than package.

Product must be present at

leak site

Less electrically

conductive than

liquid product.

.

Row 3

Varies with product–

package, instrument, test

sample fixtures, and method parameters

Quantitative measure of electrical current passing through the test sample: provides an indirect determination of leak presence and leak location as shown by a drop in test sample electrical resistivity, with a resultant increase in voltage reading above a predetermined pass/fail limit

Nondestructive,

although impact

of test exposure

on product stability is recommended

Seconds

Laser-based gas headspace

analysis

Gas volume, path length,

and content must be compatible with instrument’s detection capability.

Allows transmission of near-IR light.

Row 1

Varies as a function of time span between analyses.

Quantitative measure of gas headspace content of the test sample by laser-based gas analysis, for a product requiring a headspace low in oxygen, carbon dioxide, or water vapor concentration; and/or low in absolute pressure.

Whole test sample leakage rate is determined by compiling readings as a function of time.

Nondestructive

Seconds

Mass extraction

Gas or liquid must be

present at leak site. Presence of liquid at leak site requires test pressures below vapor pressure. Product must not clog leak path

Rigid, or flexible

with package restraint mechanism.

Row 3

Varies with product

package, instrument, test fixtures/chamber, and method parameters.

Quantitative measure of mass flow rate resulting from test sample headspace escape or liquid product volatilization within an evacuated test chamber housing the test sample.

Quantitative pressure readings early in the test cycle indicate larger leak presence. Whole test sample leakage rate is determined by comparing the test sample mass flow results to results using leak rate standards and positive controls

Nondestructive

Seconds to minutes

Pressure decay

Gas must be present at leak site.

Product (especially liquids or semi-solids) must not cover potential leak sites

Compatible with pressure detection mode.

Rigid, or flexible with package restraint mechanism.

Row 3

Varies with product package, instrument, and method parameters

Quantitative measure of pressure drop within a pressurized test sample. Pressure drop readings are a measure of gas escape through leak paths.

Whole test sample leakage rate is determined by comparing pressure decay results to results using leak rate standards and positive controls.

Nondestructive,

unless the means

used to access

test sample interior compromises test sample

barrier.

Minutes to days,

depending on

package volume

and required

leak limit of detection

Tracer gas detection, vacuum mode

Tracer gas must be added

to package.

Tracer gas must have access to package surfaces being tested for leaks

Able to tolerate

high-vacuum

test conditions

Rigid, or flexible

with package restraint mechanism

Limited tracer gas permeability

Row 1

Varies with instrument

capability and test sample fixtures.

Quantitative measure by spectroscopic analysis of tracer gas leak rate emitted from a tracer-flooded test sample positioned in an evacuated test chamber.

Whole test sample leakage rate is calculated by normalizing the measured tracer leak rate by tracer concentration in the test sample.

Nondestructive,

unless tracer gas

introduction into

the package

compromises

test sample barrier.

Seconds to minutes

Vacuum decay

Gas or liquid must be

present at leak site.

Presence of liquid at leak

site requires test pressures

below vapor pressure.

Product must not clog leak

path.

Rigid, or flexible with package restraint mechanism

Row 3

Varies with product–package, instrument, test sample chamber, and method parameters.

Quantitative measure of pressure rise (vacuum decay) within an evacuated test chamber housing the test sample; vacuum decay readings are a measure of headspace escape from the test

sample, or liquid product volatilization.

Whole test sample leakage rate is determined by comparing vacuum decay results for the test sample to results of tests performed using leak

rate standards and positive controls

Nondestructive

Seconds to minutes