Food packaging integrity (leak) tester

01

Choose vacuum decay or bubble emission

ASTM F2338 describes vacuum decay as non-destructive detection of leaks that are not visibly detectable, needing no dyes or tracer gases: the package sits in an evacuated test chamber and leakage of headspace gas, or vaporising liquid at the leak, raises the chamber pressure. Being rapid, non-invasive and non-destructive, it is suited to 100% online testing or statistical sampling; porous lidding must be masked to stop gas migration through it. Results are accept/reject against baselines from non-leaking controls and calibrated simulated leaks. [1]

ASTM D3078 covers gross leaks in flexible packaging with a headspace by bubble emission: the pack is immersed in a fluid in a transparent vacuum chamber and bubbles show leaks. It warns that small leaks may be missed, because viscous products or entrapped air block small openings and pressure inside the pouch can force the product to plug them. [2]

Cell Instruments' bubble-emission tester, built to ASTM D3078, ASTM E515 and GB/T 15171, draws vacuum to –90 kPa in a 270 × 210 mm chamber. [4] Labthink's C690H uses vacuum decay and pressure decay to ASTM F2338 and USP <1207> for vials, ampoules, cartridges, infusion bottles and prefilled syringes, with stated repeatability of ±1 µm and a 0.5–0.7 MPa air supply. [3]

Give the supplier the package types (pouch, tray, cup, bottle), materials and any porous lidding, headspace volume and product (dry, liquid, viscous), the smallest leak to detect, required throughput and whether 100% inline or sampled, reject handling, data integrity needs, and air and power supply.

02

Match detectable hole size and sensitivity

ASTM F2338's precision studies found that vacuum decay detected hole or crack defects of at least 50 µm in unlidded trays or cups at –400 mbar; holes of at least 100 µm, seal channels made with 125 µm wires and severe seal-bonding defects in trays with porous lidding at –400 mbar, with sensitivity of about 10⁻² Pa·m³/s; and holes of at least 5 µm in rigid non-porous packages, with sensitivity of about 10⁻³·⁴ Pa·m³/s for capped plastic bottles and 10⁻⁴·¹ Pa·m³/s for air-filled glass syringes. Flexible non-porous packages can also be tested, though not covered by the precision studies. [1]

ASTM D3078 states that bubble-emission sensitivity is limited to about 1 × 10⁻⁵ atm·cm³/s (1 × 10⁻⁶ Pa·m³/s), or even less sensitive as an interlaboratory test showed, and that detectable leak size depends on the product, packaging material and test parameters; because small leaks can be plugged by product, the standard is framed for gross leaks. [2]

Editorial calculation: dividing by atmospheric pressure (101,325 Pa) converts leak rates to flow at atmospheric conditions: 10⁻² Pa·m³/s is about 5.9 mL/min, 10⁻³·⁴ Pa·m³/s about 0.24 mL/min, and 10⁻⁴·¹ Pa·m³/s about 0.05 mL/min. These help compare suppliers who quote sensitivity in mL/min. [1]

03

Bench bubble testers and decay detectors on the listed pages

Listings include bench bubble-emission testers to ASTM D3078 and non-destructive vacuum and pressure decay detectors to ASTM F2338; ask whether an in-line version exists for your line speed.

04

Chamber, vacuum, transducers and the calibrated leak

In a vacuum decay tester the transducers and the calibrated leak decide where the accept/reject line sits; a bubble tester relies on the immersion tank and what the operator can see in it. [1] [2]

05

Sensitivity on your own packs comes before chamber size and cycle time

Settle sensitivity first and ask for it to be shown on your own packs: the F2338 figures change with package type and porous lidding. [1]

06

Send the package, leak and line data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Packages: [type; material; porous lidding]
Contents: [dry; liquid; viscous; headspace]
Leak: [smallest hole or flow to detect]
Method: [vacuum decay; pressure decay; bubble]
Use: [100% inline; sampled; lab]
Throughput: [packs per minute]
Data: [records; audit trail]
Utilities: [air; power]

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