UN sac à glace sec does not leak meltwater. Dry ice sublimates straight to CO₂ gas, so any “wet” you see on a sac à glace sec or carton is condensation from humid air, or frost thawing as the surface warms. You can stop it with insulation, a vapor barrier, smart label placement, and safe venting that meets 2025 règles.
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Why “sweat” happens: Dew point physics for a sac à glace sec in real warehouses and vans
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How to stop drips: A 6‑step pack‑out that keeps a sac à glace sec dry on the outside
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Sizing the refrigerant: How much dry ice a sac à glace sec needs for 24–72 h lanes
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Sécurité & conformité: UN1845, Voici pi 954 (2025), and why venting a sac à glace sec is mandatory
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Dry vs. gel: When a sac à glace sec beats gel packs—and when gels are smarter
Why does a sac à glace sec “sweat” instead of leak water?
Réponse de base: UN sac à glace sec never makes liquid water; it makes CO₂ gas. The “sweat” is moisture from the air condensing on a surface colder than the dew point, or frost that later thaws. Think of a cold soda can on a humid day—same physics, colder surface.
What’s going on: When warehouse or last‑mile air hits a sac à glace sec that is far below freezing, the outer film or carton sits under the local dew point. Water vapor becomes droplets or frost on that cold surface. As the route progresses and the surface warms, frost turns to visible water. Your sac à glace sec didn’t leak; the air did. Use insulation to keep the outer surface warmer than the dew point, and add a vapor barrier to shield fiberboard.
Dew‑point thresholds for a sac à glace sec
What to watch, at a glance
| Facteur | Typical value | Ce que cela signifie | Pour toi |
|---|---|---|---|
| Température ambiante | 23 ° C / 73 ° F | Warm air carries more moisture | Higher sweat potential |
| Relative humidity | 60–75% | Higher RH → higher dew point | Plan barriers/absorbents |
| Dew point | 15–20 ° C | Condensation threshold | Keep outer wall ≥ dew point |
| Outer carton surface | 5–15 ° C | Below dew point in most lanes | Expect “sweat” without fixes |
Conseils pratiques
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Warm the outside, not the payload: Add insulation or a foil/PE liner so the outer wall of the sac à glace sec stays at/above the dew point.
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Move paperwork: Put labels on a warm sleeve or second carton panel, away from cold spots on the sac à glace sec.
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Limit humid air exchange: Pack fast in a cooled room; keep doors shut on muggy docks.
Field case: A seafood shipper saw soaked labels in summer. After adding a foil‑laminated liner + double‑wall carton to warm the surface and moving labels to a sleeve, “wet box” complaints fell near zero with no temperature excursions.
Will a sac à glace sec leak water inside the box?
Réponse courte: No—any interior moisture is from humid air that got in, or frost that later thawed. Add a vapor‑tight inner liner, but keep the outer package vented so CO₂ from the sac à glace sec can escape safely.
Causes of interior “wet”: Air exchange during handling, damp product packaging, and cold inner films sitting below dew point. A sealed sac à glace sec is not the culprit; sealing is unsafe and non‑compliant anyway. Use a vapor barrier to trap cold at the core and protect fiberboard from moisture ingress.
Pack‑out steps to stop a sac à glace sec from “sweating”
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Pre‑condition shipper in a cool, dry room (30–60 min).
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Load dry ice into a sac à glace sec; cinch, Ne sceller pas hermétiquement.
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Insert into a foil/PE vapor barrier; close the liner at the top.
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Use adequate insulation (EPS/EPP/VIP or high‑R paper liners).
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Place labels on a warm sleeve or secondary outer carton.
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Vent safely—packages must not be airtight (UN1845, Voici pi 954).
How it helps: The inner barrier reduces moisture ingress; more insulation keeps the outer wall above the dew point; venting from the sac à glace sec prevents pressure and keeps performance consistent.
How much dry ice should a sac à glace sec carry to avoid over‑cooling the outer wall?
Règle: Plan ~ 5 à 10 lb par 24h depending on insulation and lane heat load. More mass holds temperature longer but can drop the carton surface further below the dew point if insulation is thin. Balance dose, isolation, and dwell time.
Quick estimator for a sac à glace sec (copy/paste)
Validate with a small A/B test and data loggers; adjust for summer/winter lanes.
3‑step self‑check (engagement tool)
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Is your packing room ≤20 °C and RH under control?
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Is the outer wall of the sac à glace sec likely ≥ local dew point?
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Are vents unobstructed and labels placed on a warm sleeve?
Is a sac à glace sec safe and compliant in 2025 (UN1845, Voici pi 954)?
Yes—if it’s vented and marked. Dry ice bag shipments must permit CO₂ to escape, carry UN1845 marks, and declare net dry‑ice mass. Faire pas make the package airtight. Worker safety: ventilate vehicles and rooms; follow exposure guidance.
Key notes for 2025:
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Venting required: Never seal a sac à glace sec hermétique.
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Marquage: “Dry ice / Dioxyde de carbone, solide,” UN1845, and net mass (kg).
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Air acceptance: Follow IATA DGR 66th Edition (PI 954).
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Sécurité: Handle sac à glace sec with gloves; ventilate to avoid CO₂ buildup.
Dry ice bag vs gel packs—when does water really matter?
If zero free water at delivery is critical, un sac à glace sec wins. It generates no meltwater. For 2–8 °C lanes, sweat‑proof gels are often simpler with fewer hazmat steps. Combine wisely if you use both.
| Cas d'utilisation | Dry ice bag | Packs de gel | What to do |
|---|---|---|---|
| Aliments surgelés (≤ −18 ° C) | Long hold, no meltwater | Can create condensation as they warm | Prefer dry ice + barrier |
| Chilled 2–8 °C | Over‑cool risk | Tunable and non‑hazmat | Prefer sweat‑proof gels/PCMs |
| Label integrity | Needs condensation control | Needs absorbent control | Use label sleeve + barrier |
| Air compliance | UN1845 rules apply | Not dangerous goods | Choose based on temp target |
Practical scenario: Switching to a sac à glace sec with a foil liner and label sleeve cut “wet box” claims by >80% in 2‑day lanes, with compliance ≥99%.
2025 trends that make a sac à glace sec drier and smarter
Quoi de neuf: Reusable VIP shippers that keep outer walls warm, PFAS‑free paper liners with better barrier performance, and broader use of IoT loggers for temp/RH/CO₂. These reduce condensation windows and waste while supporting sustainability goals.
Dernier en un coup d'œil
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Reusable/VIP expansion: Warmer outer surfaces for the same payload window
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Barrier upgrades: Foil/PE and next‑gen papers replace legacy coatings
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Smarter ops: Lane analytics + self‑checks standardize sac à glace sec success
Perspicacité du marché: Cold‑chain packaging grows steadily on biologics and e‑grocery volumes; hybrid PCM + sac à glace sec strategies right‑size dose and cut moisture‑related claims.
FAQ
Does a sac à glace sec sweat or leak water?
Non. Dry ice sublimates to CO₂ gas. “Sweat” is condensation or thawed frost on cold surfaces. Control dew point exposure with insulation and a vapor barrier.
Why was my carton wet after using a sac à glace sec?
Fiberboard absorbs condensation when its surface sits below the dew point. Add a foil/PE liner, use dual absorbent pads, and move labels to a warm sleeve.
Combien de glace sèche pour 48h?
Typically 12–16 lb in quality EPS; more for thin foam or hotter lanes. Validate with data loggers before scaling.
Can I seal a sac à glace sec to reduce moisture?
Non. Packages must vent gas by rule. Hermetic sealing is unsafe and non‑compliant. Use internal vapor barriers instead.
Résumé & Recommandations
Points clés: UN sac à glace sec doesn’t make water; the air does. Keep outer surfaces above the dew point with insulation and a vapor barrier, place labels on a warm sleeve, and keep packages vented and marked per UN1845/IATA PI 954. Plan ~5–10 lb per 24 h and validate by lane.
Étapes suivantes (CTA):
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Run a 2‑box A/B this week: current vs. foil/PE barrier + manche.
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Log temp/RH/CO₂ on one high‑humidity lane.
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Standardize a 6‑step sac à glace sec pack‑out in your SOPs.
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Talk to Tempk for a lane‑specific “no‑sweat” pack‑out template.
À propos du tempk
We are a cold‑chain packaging and analytics team focused on dry ice, PCMS, and compliant shippers. We pair validated EPS/VIP systems with practical moisture control—barriers, absorbents, and process checks—so your sac à glace sec shipments arrive dry and on‑spec. Typical outcomes: >80% fewer wet‑box complaints and measurable cost savings from right‑sized refrigerant loads.
Ready for a dry, compliant pack‑out? Demander un sac à glace sec audit and validation plan today.
