Last updated: March 2026
Your packages pass every test on the production floor. Then they go on a truck through the Rockies, or into the belly of a cargo plane, and something changes. The seals that looked fine at sea level are under real pressure now. Headspace gas inside the package expands as atmospheric pressure drops. Marginal seals that were already near their limit finally give way. By the time the product reaches its destination, the seal has failed – and nobody saw it coming.
High altitude simulation testing exists to catch those failures before they ship. It recreates the pressure changes your packages experience during air freight and high-altitude ground transport, so your QA team can find the weak points in a controlled environment instead of discovering them at the customer’s door.
This guide covers what the test actually does, why the physics matter, how to set the right vacuum level for your shipping route, and how to pair it with a detection method to get a complete result.
What Is High Altitude Simulation Testing?
High altitude simulation testing is a package conditioning method, not a leak detection method. Governed by ASTM D6653, it recreates the pressure differential that packages experience during air shipment or high-altitude ground transport by drawing a controlled vacuum inside a sealed test chamber.
The test places packages under the pressure conditions they’ll face in transit. If seals are sound, nothing happens. If they’re marginal, the stress reveals it. What the test does not do is tell you where the leak is or whether a leak occurred at all – that requires a detection method paired immediately after conditioning.
ASTM D6653 is commonly paired with a detection method such as ASTM D3078 (bubble emission testing), ASTM D4991 (rigid containers), or ASTM D5094 (threaded closures), depending on your package type.
Think of it as a two-act test: D6653 applies the stress, your detection method shows you the result.
Why Packages Fail at Altitude
Atmospheric pressure drops as altitude increases. At sea level, pressure sits at around 29.9 inHg. At 10,000 feet – well within range for nonpressurized feeder aircraft and ground transport over mountain passes – that drops to around 20.6 inHg. Pressurized cargo holds on commercial jets are typically maintained at an equivalent of around 8,000 feet during flight.
That pressure drop matters because of what’s inside your package. Any headspace gas – the air or modified atmosphere trapped inside a sealed pouch or bag – pushes outward as external pressure falls. The package expands. Seals stretch. Channel defects that were essentially closed at sea level can open under that load.
Here’s the critical point: altitude simulation doesn’t create defects. It reveals seals that were already near their failure limit. A package that fails this test would have failed in the real world too; you just found out in your lab instead of at a distribution center. FlexPak’s transparent acrylic test chamber lets operators watch this happen in real time – you can see which packages are expanding toward their seal limit during the vacuum hold, before anything actually fails.
Cold-chain products add another layer. ASTM D6653 calls for specimens to be conditioned to around 42°F (5.6°C) for at least 24 hours before testing, reflecting the cold temperatures packages typically experience during refrigerated air freight. Cold materials are less pliable, seals are stiffer, and the combined stress of cold plus pressure differential is more representative of what actually happens in transit. For more on cold-chain packaging challenges, see our guide to cold-chain packaging integrity.
How to Set the Right Vacuum Level for Your Route
This is where most altitude testing programs go wrong. There’s no single “correct” vacuum level – the right setting depends on the highest pressure differential your packages will actually face in shipping.
Four principles guide the selection:
1. Match your test pressure to your transit conditions. Air freight creates bigger pressure changes than ground transport. Packages shipped by nonpressurized feeder aircraft may experience altitudes as high as around 19,740 feet based on field data in ASTM D6653 Appendix X1.3. Ground transport over mountain passes typically reaches around 12,000 feet.
2. Know the standard’s default targets. ASTM D6653 specifies two default test altitudes depending on how specimens are conditioned: 16,000 feet (±5%) for cold-conditioned specimens (§9.1.1) and 14,000 feet (±5%) for ambient-conditioned specimens (§9.1.2). If you’re building a compliance-ready test protocol, these are your starting points – they’re what an auditor will look for.
3. Use 12 inHg as a practical North American benchmark. Many manufacturers testing for North American distribution set their vacuum to 12 inHg. At this level, if your seals hold, they’ll hold under almost any domestic shipping condition. It’s a well-validated starting point for food, pharmaceutical, and consumer goods packaging.
4. Find your package’s burst point, then test at around 90% of that. Run a few samples to find the vacuum level at which seals begin to fail. Then set your standard test pressure at approximately 90% of that figure. For example, if seals fail around 16 inHg, test at 14 inHg. This gives you a meaningful stress test without routinely destroying packaging. For more on how burst point testing works, see our overview of burst testing for packaging.
Package type doesn’t determine your vacuum level – your shipping method does. Whether you’re testing flow wraps, stand-up pouches, or rigid trays, the question is always: what’s the worst pressure differential this package will face in transit? That answer comes from your route, not your package format. For a broader look at how to set a package testing standard, we’ve covered the full process separately.
Not sure which vacuum level matches your shipping route? Get a quote in 24 hours and we’ll confirm the right setup for your package type and conditions.
Altitude-to-Vacuum Setpoint Reference Chart (ASTM D6653)
The FlexPak leak detector’s vacuum gauge must reach the corresponding setpoint to simulate the target altitude pressure. Always subtract your Facility Vacuum Offset (FVO) – recorded during installation qualification – when setting targets.
Imperial (feet / inHg)
| Altitude (ft) | Absolute Atmospheric Pressure (inHg) | Vacuum Gauge Setpoint (inHg) |
| 0 | 29.9 | 0 |
| 1,000 | 28.9 | 1.0 |
| 2,000 | 27.8 | 2.1 |
| 3,000 | 26.8 | 3.1 |
| 5,000 | 24.9 | 5.0 |
| 8,000 | 22.2 | 7.7 |
| 10,000 | 20.6 | 9.3 |
| 14,000 | 17.57 | 12.35 |
| 15,000 | 16.9 | 13.0 |
| 16,000 | 16.21 | 13.71 |
| 20,000 | 13.8 | 16.1 |
Values derived from ASTM D6653. Always apply your Facility Vacuum Offset before setting test targets. The 14,000 ft and 16,000 ft rows correspond to the standard’s default target altitudes per §9.1.2 and §9.1.1 respectively.
Metric (meters / kPa)
| Altitude (m) | Absolute Atmospheric Pressure (kPa) | Vacuum Gauge Setpoint (kPa) |
| 0 | 101.3 | 0 |
| 305 | 97.7 | 3.6 |
| 610 | 94.2 | 7.1 |
| 1,524 | 84.3 | 17.0 |
| 2,438 | 75.3 | 26.0 |
| 3,048 | 69.7 | 31.6 |
| 4,267 | 61.6 | 39.7 |
| 4,877 | 57.2 | 44.1 |
| 6,096 | 46.6 | 54.7 |
Values derived from ASTM D6653. Always apply your Facility Vacuum Offset before setting test targets.
A note on Facility Vacuum Offset (FVO): Every FlexPak unit ships calibrated and ready to test. During installation qualification (IQ), you record your facility’s FVO – the difference between your local atmospheric pressure and sea level. This offset is subtracted from every vacuum setpoint you program, so your gauge targets are accurate to your actual location, whether you’re in Denver or Miami.
D6653 and D3078: How the Two Tests Work Together
These two standards are designed to be used in sequence. Neither gives you the full picture on its own.
ASTM D6653 conditions the package. It applies the altitude-equivalent pressure differential and holds it for the prescribed time – typically 60 minutes at cruise altitude per §9.2, though this can be adjusted based on your shipping scenario. The standard calls for a controlled ascent rate of approximately 1,000 feet every 30 to 60 seconds, a hold at simulated cruise altitude, and a descent at the same rate. Results are qualitative: you know the package was subjected to altitude stress. You don’t yet know what happened to the seals.
ASTM D3078 is the detection step. After altitude conditioning, the package goes into the bubble emission tester. The package is submerged in fluid, vacuum is drawn, and any escaping headspace gas produces a visible, steady stream of bubbles at the leak point. In around 30 seconds, you know if there’s a leak and exactly where it is. For a full walkthrough of the bubble emission method, see our guide to ASTM D3078 bubble leak testing.
If you have a FlexPak FPFAT unit, here is how it should be run. D6653 conditioning runs as Test 1, D3078 bubble emission testing runs as Test 2, back-to-back with no manual steps between them. Set up your altitude recipe as Test 1 and your bubble emission recipe as Test 2, run Test 1 and then Test 2 afterward.
| ASTM D6653 | ASTM D3078 | |
| Method type | Conditioning | Detection |
| What it does | Simulates altitude pressure differential | Detects gross leaks via bubble emission |
| Detects leaks? | No | Yes |
| Run alone? | No — must pair with detection method | Yes, independently |
| Destructive? | No | No |
| Results | Qualitative (package was stressed) | Visual (bubble location = leak location) |
For a full comparison of air leak test methods for packaging, including where altitude simulation fits alongside vacuum decay and other approaches, we’ve put together a separate overview.
Which Packages and Industries Need Altitude Testing
If your product ships by air or crosses mountain terrain by ground, altitude simulation testing belongs in your QA program. That covers more categories than most programs account for.
Food and beverage – especially modified atmosphere packaging (MAP). The protective gas atmosphere inside nitrogen-flushed pouches, meat trays, and dairy packs becomes a liability at altitude: more headspace gas means more outward pressure on seals. Snack foods, seafood, and any product in flexible packaging should be evaluated. Brands like Nestlé, Hershey’s, and Smucker’s use FlexPak testing across their flexible packaging lines.
Pharmaceutical and medical device. For products requiring sterile barrier integrity, a seal failure at altitude isn’t just a quality issue – it’s a patient safety issue. ISO 11607 and its related guidance commonly lead teams to include distribution hazard testing, and altitude simulation is a recognized part of that evaluation when the distribution environment warrants it. Cold-chain pharma products are doubly exposed, given the combined stress of low temperature and low pressure. See our guide to pharmaceutical package testing for the full picture.
Cold-chain products broadly. Refrigerated and frozen products shipped by air experience both temperature and pressure stress simultaneously. D6653’s pre-conditioning to around 42°F is specifically designed to reflect this scenario – the cold stiffens seals right before the pressure change hits.
E-commerce and direct-to-consumer. Products shipped direct to consumers increasingly travel via small parcel air networks that may include nonpressurized feeder aircraft. If your product moves through air parcel networks, altitude exposure is real. Our overview of e-commerce package testing covers the full range of distribution hazards this channel introduces.
Any product crossing mountain passes by ground. Colorado, the Sierra Nevada, the Canadian Rockies: trucks crossing these routes regularly reach altitudes of 10,000 to 12,000 feet. If your ground distribution covers these regions, your packages face meaningful pressure differentials without ever leaving the truck. Co-manufacturers and co-packers supplying national retailers need to account for the full distribution range, not just the first leg of the journey. Package performance testing covers how to build a program that accounts for the full distribution environment.
How to Run Altitude Simulation Testing with FlexPak
FlexPak FPFAT fully automatic units with altitude simulation capability run D6653 testing through a dedicated recipe system. Once validated, operators select their recipe and press start – no manual calibration required run to run.
Setting up an altitude test recipe:
From the main menu, select Altitude Test. Altitude recipes use IDs #25–50. Each recipe stores:
- Test (Flight) Altitude – the vacuum level representing your simulated altitude
- Ascent Rate – approximately 1,000 feet every 30 to 60 seconds, per standard protocol guidance
- Descent Rate – same rate as ascent
- Time at Maximum Cruise Altitude – typically 60 minutes per D6653 §9.2, set in hours, minutes, seconds
Set your vacuum level using the altitude-to-vacuum chart above. Subtract your Facility Vacuum Offset (FVO) to get your actual gauge setpoint.
Running the combined D6653 + D3078 sequence:
The 1+2 Run function runs altitude conditioning (Test 1) immediately followed by bubble emission testing (Test 2), with no manual steps required between them. Set up your altitude recipe as Test 1 and your bubble emission parameters as Test 2, then press 1+2 Run. The system handles the transition automatically.
After testing, review your D3078 results: steady bubble streams indicate leak locations. Note exactly where bubbles appear — this tells you which seal area needs attention and what machine adjustment may be required. For guidance on interpreting results and avoiding common errors, see our post on ASTM D3078 bubble leak testing mistakes.
Ready to add altitude simulation to your testing program? Get a quote in 24 hours – we’ll confirm the right FlexPak configuration for your shipping conditions and help you set your first test recipe.
Frequently Asked Questions
Does ASTM D6653 detect leaks in packaging?
No. ASTM D6653 is a conditioning method – it simulates the pressure changes packages experience at altitude but does not identify leaks on its own. To detect leaks, pair D6653 conditioning with a detection method immediately after: ASTM D3078 (bubble emission) for flexible packages, D4991 for rigid containers, or D5094 for threaded closures. D6653 applies the stress; the detection method shows you whether any seals failed.
What vacuum level should I use for altitude simulation testing?
The right vacuum level depends on your shipping conditions, not your package type. ASTM D6653 specifies default targets of 16,000 ft for cold-conditioned specimens and 14,000 ft for ambient-conditioned specimens. For a practical North American benchmark, many manufacturers test to 12 inHg – this covers typical air freight and mountain ground transport. Best practice is to find the vacuum level at which your seals begin to fail, then test at approximately 90% of that figure. Use the altitude-to-vacuum chart in this article to match your setpoint to your shipping route.
Do all products need altitude simulation testing?
Not all products, but more than most QA programs account for. Any product shipped via air freight, nonpressurized feeder aircraft, or over mountain passes should be evaluated. This includes modified atmosphere food packaging, cold-chain pharmaceutical products, medical device sterile barrier systems, and e-commerce products shipped through air parcel networks.
Can I run altitude simulation and bubble emission testing on the same FlexPak unit?
Yes – on FlexPak FPFAT units. The 1+2 Run function runs D6653 conditioning and D3078 bubble emission testing back-to-back without manual steps between them. Altitude recipes use IDs #25–50; bubble emission recipes use IDs #1–24.
How is altitude simulation testing different from burst testing?
Burst testing applies increasing internal pressure until the package seal fails – it’s a destructive test used to determine maximum seal strength. Altitude simulation applies external pressure reduction (vacuum) to simulate real transit conditions; it’s a non-destructive conditioning method. The two tests measure different things and are not interchangeable. Burst testing tells you the ceiling; altitude simulation tells you whether your packages can handle the conditions between here and your customer.
Altitude simulation testing is one of the most practical additions a QA program can make — and one of the most overlooked. If your products travel by air or cross high terrain by ground, your seals face pressure differentials your production floor never sees. This test puts your packaging through those conditions before it ships, so weak seals show up in your lab instead of at your customer’s door.
The setup is straightforward, the test runs fast, and the results are clear. The harder part is knowing what vacuum level to use and how to pair the conditioning with a detection method – which is exactly what this guide is for.
Ready to add altitude simulation to your testing program? Get a quote in 24 hours and we’ll confirm the right FlexPak configuration for your shipping conditions.
About the Author: Gordon Bruce, Sales & Application Expert, FlexPak Inc. Gordon has spent years helping manufacturers across food, pharmaceutical, and industrial packaging solve leak detection and seal integrity challenges. He works directly with QA teams to match testing equipment to real-world shipping and compliance requirements.