Refrigerant Dry Ice Packs: 2025 Buyer’s Guide

Refrigerant dry ice packs keep products ultra‑cold for long routes while controlling cost and risk. If you need −70 °C performance for 24–120 hours, these packs can outperform gel or PCM systems—when you size, vent, and label them correctly. Below you’ll find a practical sizing method, current 2025 rules, and side‑by‑side trade‑offs so you can choose confidently and ship with fewer temperature excursions.

• Where refrigerant dry ice packs truly excel for ultra‑cold lanes and what “−78.5 °C” means in the real world. USGS

• How to size refrigerant dry ice packs using a quick calculator and realistic sublimation rates. Sonoco ThermoSafe+1

• 2025 compliance essentials (UN1845, FAA/TSA 2.5 kg, USPS 5 lb, IATA updates), plus labeling and venting. Federal Aviation Administration+2Postal Explorer+2

• Dry ice vs. gel/PCM packs—when to switch, hybrid builds, and cost/weight impacts.

• Safety basics (PEL/REL, IDLH, ventilation) to protect teams and facilities. CDC+1

• 2025 sustainability pressures (EU PPWR timelines) and what they mean for reusable shippers. Environment+1

What are refrigerant dry ice packs, and when should you use them?

Short answer: Refrigerant dry ice packs are insulated parcel systems that use solid CO₂ (dry ice) as the cooling medium to hold product near −70 °C for long durations. Use them for biologics, specialty foods, and lab samples requiring deep‑frozen conditions. Dry ice sublimates (turns to gas) at about −78.5 °C, so it never melts into water and won’t soak cartons. USGS

Why that matters: You get stable, ultra‑cold performance without condensate—ideal for vaccines, enzymes, and high‑fat frozen foods. Because dry ice gives off CO₂ gas as it sublimates, your shipper must vent and be properly labeled per 2025 rules. Passenger‑carried amounts are capped; carrier shipments require UN1845 and net weight marks. We’ll cover the exact limits and labels below so your packs pass acceptance on the first try. Federal Aviation Administration+1

What temperature do refrigerant dry ice packs actually hold?

Detail: Dry ice transitions directly from solid to gas at −78.5 °C (−109.3 °F). In practice, product temperature depends on payload mass, insulation (EPS, PUR, VIP), packout geometry, and opening frequency. Laboratory work and industry guidance show typical sublimation rates ranging from ~3–8% per day in well‑insulated systems, but rates climb sharply with thin walls or frequent access. Expect faster loss with pellets vs. blocks. Sonoco ThermoSafe+1

Practical tips and suggestions

• For weekly biologics lanes: Precondition shipper to ≤ −20 °C, use blocks in lower layer, pellets to fill voids, and add a vent path.

• For export seafood: Use VIP liners to control weight, and stage a top‑off port to replenish at hub handoffs.

• For field kits: Pre‑bag dry ice; include a “vent check” sticker and a CO₂ exposure card for staff.

Real‑world case: A gene‑therapy lab cut excursions by 42% after switching to blocks‑plus‑pellets and adding a one‑way vent disk. The same lane maintained −65 °C or colder for 72 hours with 15% less dry ice than the previous design.

How much dry ice do refrigerant dry ice packs need?

Short answer: Start with a simple rule of thumb: 5–10 lb (2.3–4.5 kg) of dry ice per 24 hours in a standard, well‑insulated shipper. For higher‑R designs (VIP), you can target the low end; for thin EPS or hot climates, plan the high end. Laboratory and field data show ~2%/hour in small parcels during flight profiles, so build a safety margin. WestAir+1

Expanded guidance: Your dry‑ice load must cover (1) heat gain through the walls, (2) product warm‑up, and (3) handling events. You’ll get better accuracy by combining a baseline daily rate with a time factor and a climate factor. For bio‑payloads that are already deep‑frozen, you only fight ambient heat; for warm payload starts, add extra for pull‑down. Use blocks where possible; they last longer than pellets at the same mass. dryiceproduction.com

Quick sizing calculator (use before each lane launch)

Example: 60‑hour route, VIP shipper (R=6), hot season (C=1.2), first run (S=1.25):
Dry_Ice_lb ≈ (60/24) × 6 × 1.2 × 1.25 = 22.5 lb (round to 24 lb).

Tip: Validate against typical field rates (5–10 lb/day). If you’re outside that band, re‑check insulation and packout.

Are refrigerant dry ice packs safe and compliant in 2025?

Short answer: Yes—when you vent, label, and stay within limits. For airline passengers, the limit is 2.5 kg (5.5 lb) per person, with airline approval and non‑airtight packaging. For USPS domestic air, a mailpiece may contain ≤ 5 lb of dry ice. Commercial shipments must follow IATA DGR: mark UN1845, proper shipping name, net weight, and apply a Class 9 label; operators may impose aircraft‑type limits. Federal Aviation Administration+2Postal Explorer+2

What to do today: Use a vented outer, insulated inner, and print the UN number and net kg on the box side. Acceptance teams increasingly use checklists; the 2026 IATA dry‑ice acceptance form mirrors what many carriers already request. When in doubt, attach the checklist to your airway bill and include the net dry‑ice weight on documentation. IATA

Safety limits and staff protection (simple, practical)

CO₂ exposure: OSHA’s 8‑hour limit and NIOSH’s recommended exposure limit for CO₂ are 5,000 ppm; NIOSH’s IDLH is 40,000 ppm. Train staff to open shippers in ventilated areas, never seal dry ice in airtight containers, and avoid walk‑ins with poor airflow. OSHA+1

Practical tips and suggestions

• Warehouse SOP: Place opening tables near exhaust or open dock doors; post a 5‑step “vent‑check” placard.

• Traveler SOP: Pre‑print a simple “DRY ICE / 2.5 kg or less” card for baggage.

• Cargo SOP: Add “Net dry ice: X kg” on two adjacent sides; attach operator checklist to the pouch.

Actual case: A biotech reduced carrier rejections to near zero after adding UN1845 marks and net‑kg print to two panels, plus a perforated vent hole with a tamper label. Post‑change, five consecutive lanes cleared acceptance without rework.

How do refrigerant dry ice packs compare to gel and PCM packs?

Short answer: Refrigerant dry ice packs lead for below −20 °C setpoints, long holds, and small interiors. Gel/PCM packs win for 2–8 °C or −20 °C lanes, returns programs, and carrier rules that disfavor dry ice. Hybrid packouts (dry ice base + PCM buffer near product) can stabilize curves and reduce weight.

Expanded view: Think of dry ice as a “deep‑freeze engine.” It’s powerful but needs venting and labeling. PCMs are “thermostats” at precise setpoints (e.g., −21, +5 °C) and are easier to reuse. For last‑mile, PCMs simplify hand‑offs; for international lanes or biotech, dry ice often remains the smallest, lightest path to 72–120 hours.

When to choose what (decision guide)

• Pick refrigerant dry ice packs when: ultra‑cold, small payloads, long flights, and strict stability curves.

• Pick PCM/gel when: setpoint is −20 °C or 2–8 °C, reverse logistics matter, or staff training is minimal.

• Pick hybrid when: you need −60 °C near the ice layer but protect the product with −20 °C PCM spacers.

Designing refrigerant dry ice packs: insulation, venting, labels

Short answer: Durable PUR or VIP walls cut dry‑ice mass and freight; blocks extend hold time; vented lids prevent pressure issues; UN1845 + Class 9 + net kg labeling accelerates acceptance. A little design for assembly (DFA)—pre‑bagging ice, printed panels—reduces packout mistakes.

Deep dive: Thermal design is about minimizing heat leak (U·A·ΔT). VIP panels slash A and U without adding bulk. Blocks lower surface area vs. pellets, reducing sublimation. Operationally, locate venting away from the payload and provide a one‑way check if the box might be stacked tightly.

UN1845, Class 9, and airline limits (2025 snapshot)

• Passengers: ≤ 2.5 kg per person; airline approval; non‑airtight packaging; mark “Dry ice” and net quantity or “≤ 2.5 kg.” Federal Aviation Administration

• USPS domestic air: ≤ 5 lb per mailpiece; packaging must allow gas release. Postal Explorer

• IATA cargo: Mark UN1845, proper name, net kg on outer, and apply Class 9 label; aircraft‑type limits apply per 2025 DGR updates/addenda. IATA

Insulation options at a glance

Operations playbooks for refrigerant dry ice packs

Direct answer: Standardize on one packout per lane, pre‑print UN1845 panels, and implement a two‑point weight check (before/after) to verify net kg. For biologics, stage a hybrid buffer around the payload and avoid opening during transit.

Expanded explanation: The biggest excursion risks are at hand‑offs. Use a “Don’t Open” strip across the lid and a QR card to SOPs. At hubs, top‑off stations can add 10–20% mass in under a minute. For food, pre‑freeze to −20 °C or colder and prevent voids with pellets.

Food, biologics, and lab kits—specific moves

• Food: Freeze payload solid; use blocks under, pellets around; reinforce corners; post “vent here.”

• Biologics: Hybrid buffer with PCM around the carton; document net kg and shipper ID on the label.

• Lab kits: Pre‑bag dry ice; add CO₂ safety insert; provide gloves and face shield in a consumables kit.

Actual case: A seafood exporter adopted VIP liners and blocks, cutting dry‑ice mass by ~28% while holding −60 °C for 72 h in midsummer across two hubs. Damaged‑label returns fell after adding side‑panel net‑kg prints.

Troubleshooting refrigerant dry ice packs in transit

Direct answer: If hold time is short, check insulation gaps, pellet‑only loading, and airtight lids first. If labels fail acceptance, confirm UN1845, Class 9, and net kg are printed and visible.

Deeper fixes: Map excursions to events: “openings,” “hub time,” or “final‑mile delays.” Add data loggers and shock/light indicators. If the route is volatile, redesign with VIP or hybrid buffers and raise the safety factor in your sizing formula to 1.25–1.35.

Field checklist (use at the bench)

• Vent path clear?

• Net kg printed on side panel?

• Blocks on bottom, pellets filling voids?

• QC weighed? Signed?

• Logger started? Sticker applied?

2025 trends for refrigerant dry ice packs

Trend overview: Three forces shape 2025 decisions: (1) regulatory clarity around dry‑ice marking and airline limits in the latest IATA DGR addendum, (2) greater safety emphasis on CO₂ exposure (PEL/REL and IDLH training), and (3) packaging‑waste pressure in the EU’s PPWR, which entered into force on 11 February 2025 and phases in reuse/recyclability obligations over the next 18 months. Expect more reusable shells with replaceable VIP liners. IATA+2OSHA+2

What’s new and why it matters

• IATA acceptance checklists: Standardized forms streamline hand‑offs; attach them to your pouch. IATA

• CO₂ safety refreshers: Teams double‑check ventilation and PPE due to clear PEL/REL/IDLH guidance. OSHA+1

• EU PPWR reality: Reuse and recyclability targets push VIP‑based reusables and lighter outers. Environment+1

Market insight: Airlines and integrators continue to cap per‑piece dry ice for certain aircraft; labeling and net‑kg prints speed acceptance. Meanwhile, COVID‑era ultra‑cold lanes have normalized: many current vaccines now arrive frozen and may be refrigerated for extended periods after receipt, reducing dry‑ice dwell at the last mile. Still, long‑haul biologics rely on dry ice for comfort margin. Pfizer Medical

Frequently Asked Questions

Q1: What temperature do refrigerant dry ice packs hold?
They stabilize near −78.5 °C at the ice interface. Product temperature varies with insulation and geometry, but dry ice won’t create liquid water like frozen gel does. USGS

Q2: How much can I carry on a plane?
For passengers, ≤ 2.5 kg (5.5 lb) per person with airline approval; packaging must be vented and marked “Dry ice.” Federal Aviation Administration

Q3: What about USPS?
USPS allows ≤ 5 lb of dry ice per domestic air mailpiece; packages must permit gas release and be properly marked. Postal Explorer

Q4: What’s a realistic sublimation rate?
Plan around 5–10 lb per 24 h in a good insulated cooler; small flight parcels often show ~2%/hour. Use blocks to slow loss. WestAir+1

Q5: Is dry ice safe to handle?
Yes, with gloves and ventilation. OSHA/NIOSH place time‑weighted limits at 5,000 ppm and an IDLH at 40,000 ppm for CO₂. OSHA+1

Summary and recommendations

Key takeaways: Refrigerant dry ice packs are the best choice for ultra‑cold, long‑duration lanes. Size them with a simple (time × daily rate × climate × safety) method, and choose blocks whenever possible. In 2025, you must vent, mark UN1845 + net kg + Class 9, and respect 2.5 kg passenger and 5 lb USPS thresholds. Train for CO₂ safety; log temperatures; standardize packouts.

Action plan:

1. Select insulation (PUR/VIP) for your lane and run the quick calculator.

2. Lock a single SOP per lane; print UN1845 panels with net kg.

3. Pilot 5–10 shipments with data loggers; adjust R, C, S factors.

4. For EU routes, start reusable trials to prepare for PPWR obligations.

5. Roll out training on CO₂ exposure and acceptance checklists.

About Tempk

We engineer cold‑chain packaging that is simple to pack, easy to approve, and hard to fail. Our refrigerant dry ice packs and VIP hybrid systems balance weight and hold time, with printed UN1845/net‑kg panels for faster acceptance. Customers typically cut dry‑ice mass by 15–30% while keeping the same or better duration. We pair designs with lane‑specific calculators and SOP cards so your team can pack right on day one.

Next step: Contact our team for a lane assessment and a right‑sized refrigerant dry ice pack prototype for your route.