What temperature are dry ice packs under real shipping conditions? At standard pressure, dry ice sits at −78.5 °C (−109.3 °F). In a shipper, internal air typically holds between about −70 °C and −20 °C depending on insulation, venting, and pack placement. You’ll see why this range matters, how much dry ice to use, and how to stay compliant in 2025.
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Exact numbers: what temperature are dry ice packs at the surface, in the box air, and at the product core
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Sizing made simple: quick math for sublimation rates and a dry ice quantity estimator
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Safer pack-outs: venting, labels (UN1845), and spacing to prevent freeze damage
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Smart choices: when dry ice beats gel/PCM—and when it doesn’t
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Trends for 2025: vent membranes, edge-aware loggers, CO₂ recovery, and digital DG workflows
What temperature are dry ice packs under real shipping conditions?
Short answer: Dry ice is −78.5 °C at the source; box air stabilizes warmer (≈ −70 °C to −20 °C). Product core lags the air and stays below its spec if you size mass and insulation correctly. This is why what temperature are dry ice packs is a system question, not just a single number.
Why it matters: If you must hold ≤−18/−20 °C (ice cream, frozen desserts, some biologics), a −78.5 °C “cold battery” gives large safety headroom. For 2–8 °C, dry ice is too cold—use gel or PCM to avoid accidental freezing.
How much dry ice to start with?
A practical daily estimator is:
Dry ice (lb) = (Transit hours ÷ 24) × Sublimation rate (lb/24 h)
Plan with typical rates by shipper quality and add a 10–30 % buffer for hand-offs and ambient spikes.
| Shipper Type | Insulation Quality | Typical Sublimation (lb/24 h) | What it means for you |
|---|---|---|---|
| EPS foam (≈ 2″ wall) | Excellent | 4–6 | Great for 48–72 h lanes |
| Rigid plastic + liner | Good | 6–8 | Balanced cost/hold |
| Corrugated + liner | Moderate | 8–10 | Add mass or shorten route |
| Pallet foam crate | Premium | 10–20 / pallet | Scale with openings and cube |
Pro tip: It’s often cheaper to improve insulation than to keep adding dry ice. Better walls reduce loss across every touchpoint.
Pack placement patterns that actually work
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Top-load only: cold sinks; watch bottom warm-up on longer lanes
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Top + bottom: flatter gradients for mixed-density loads
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Surround (sides + top): most uniform profile; needs more initial mass
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Interstitial (between layers): fast pull-down; add spacers for fragile packs
Real-world snapshot: A dessert brand cut temperature excursions by 38 % after switching from top-only blocks to a surround pellet pattern with the same mass.
What temperature are dry ice packs vs. gel and PCM packs?
Bottom line: Use dry ice for frozen (≤−20 °C). Use gel/PCM for 2–8 °C or CRT.
| Cooling Element | Set-Point / Behavior | Best Use | Watch-outs |
|---|---|---|---|
| Dry ice (CO₂ UN1845) | −78.5 °C sublimes | Deep-frozen lanes | Venting required |
| Gel pack (0 °C) | 0 °C melts | Chilled food | Short hold |
| PCM −21 °C | Phase at −21 °C | Frozen foods | Pre-condition |
| PCM +5 °C | Phase ≈ +5 °C | Vaccines | Avoid freezing |
| PCM +22 °C | Phase ≈ +22 °C | CRT lanes | Needs insulation |
What temperature are dry ice packs at the product interface—and is it safe?
Contact risk: A −78.5 °C surface can freeze sensitive items on contact. Add a spacer (corrugate, foam tray) and distribute packs evenly.
Compliance checklist
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Proper name “Carbon dioxide, solid (Dry ice), UN1845”
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Net weight of dry ice on package
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Vented (never airtight) container
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Class 9 hazard label
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Clear shipper / consignee info
| Topic | Essential Practice | What to Avoid | Why it matters |
|---|---|---|---|
| Venting | Use vent gaps | Airtight lids | Prevents pressure buildup |
| Labeling | UN1845 + weight + Class 9 | Missing weights | Faster acceptance |
| Handling | Insulated gloves | Bare-hand contact | Avoids frost injury |
Practical tips
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Door cycles: minimize openings
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Logger location: near payload core
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Lane design: prefer predictable curves, not perfect symmetry
How much dry ice do you need for 24–96 h lanes?
Example: 48 h lane, EPS shipper, ≈ 5 lb / 24 h →
(48 / 24) × 5 = 10 lb + 10–20 % buffer → 11–12 lb total.
Validation beats theory—tune to your kit and lanes.
2025 trends in dry ice temperature control
Fresh in 2025: Smarter vent membranes, edge-aware loggers, CO₂ recapture, and digital DG workflows cut cost and emissions.
Highlights
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Microporous vent lids stabilize internal air
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Edge-aware loggers catch corner leaks early
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Lower-carbon dry ice from CO₂ capture
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Digital declarations reduce errors
Market insight: Frozen DTC and biologics growth favors lighter, surround pack-outs with better insulation for cost control.
FAQs
Q1: What temperature are dry ice packs at the start of a trip?
About −78.5 °C at surface/core; internal air warms to −70 °C to −20 °C depending on design.
Q2: Can I use dry ice for 2–8 °C?
No. It’s too cold—use +5 °C PCM or gel packs.
Q3: Pellets or slabs?
Pellets distribute evenly; slabs last longer. Hybrid works best.
Q4: How close can dry ice be to my product?
Avoid direct contact; use a spacer and rely on box air temp.
Q5: How long does dry ice last?
Typically 18–96 h depending on insulation, mass, and ambient.
Summary & recommendations
Key points: What temperature are dry ice packs = −78.5 °C source; box air warmer.
Use dry ice for frozen lanes, PCM/gel for 2–8 °C. Always vent, label, and log.
Next steps:
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Define target temp & lane time.
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Choose correct coolant.
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Estimate mass + 10–30 % buffer.
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Use Top+Bottom or Surround layout.
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Validate with loggers.
CTA: Ready to validate a −20 °C or −70 °C lane? Book a 10-minute pack-out review with Tempk.
About Tempk
We design validated frozen, refrigerated, and CRT pack-outs with proven insulation and accessories that hit −20 °C and −70 °C profiles reliably. Every design is backed by pilot data and SOPs that teams can follow easily.
