Waterproof Vaccine Cold Chain Transport Bags

A vaccine transport bag is not qualified because it feels cold or carries a waterproof label. It is qualified only as a fixed system that keeps every monitored payload location inside 2–8°C for a declared duration under defined summer and winter profiles: outer shell, insulation, phase-change material or conditioned ice packs, spacers, payload mass, closure, temperature logger and exact loading sequence. Its unusual waterproofing problem comes mainly from inside, because melting ice, condensation and repeated wet pack handling can pool litres of water against seams long before rain reaches the exterior. Freeze-sensitive vaccine placed directly against a frozen pack can be damaged while the centre logger still reads 5°C. For the strict distribution programme specified here, any recorded value outside 2–8°C is an excursion: quarantine immediately and reject the shipment unless the responsible vaccine authority has a pre-approved written stability disposition.

This guide defines thermal mapping, logger location, PCM selection, ice-pack conditioning, internal meltwater barriers, payload zoning, cleaning, WHO and distribution documentation, ISTA 7D-style seasonal profiles, drop and compression checks, qualification reports and custom procurement controls. It treats an excursion as a product event rather than a bag complaint and explains how institutional buyers can lock a validated packout into artwork, training and bulk inspection. The production baseline at QUANZHOU JUNYUAN BAGS — custom waterproof bag production since 2014, 4,950 m² SGS-verified facility — is MOQ 500 pieces per style, sampling in 6–10 working days and bulk in 35–50 days, FOB Xiamen.

Insulated waterproof transport bag arranged for vaccine cold chain delivery — The controlled system is the bag, coolant, payload, logger and packing sequence together.

Cold chain carrier with organized coolant and medicine compartments — A barrier between frozen packs and freeze-sensitive vials is part of the validated packout.

Waterproof medical cold chain bag prepared for route qualification — Most liquid inside a cold carrier comes from coolant condensation and meltwater rather than rain.

A 2–8°C claim belongs to a complete packout, never to an empty bag

A credible vaccine cold chain bags programme begins by refusing to separate thermal performance from waterproof medical transport construction. An empty insulated carrier has no 2–8°C duration. Temperature is produced by a particular coolant mass, phase-change temperature, conditioning method, payload, void fill and closure sequence under a particular ambient profile. Change a six-kilogram payload to one kilogram, remove two PCM plates, place cartons against the wall, or leave an air gap under the lid, and the qualified result no longer describes the shipment.

The usable claim must read like a test condition: "maintains all mapped payload points from 2.0°C through 8.0°C for 24 hours when packed with six conditioned 5°C PCM panels, a 4 kg simulated payload preconditioned at 5°C, specified dividers and logger positions, against the approved summer profile." Rounded marketing phrases such as "keeps cold all day" cannot support release, route training or an investigation.

Assign a version number to the bag, PCM pack, divider, payload arrangement and work instruction as one qualified configuration.
State minimum and maximum payload, because low thermal mass often warms and freezes faster than a full load.
Precondition payload simulants and coolant to specified temperatures; room-temperature dummy boxes produce a meaningless duration.
Map the warmest and coldest positions before choosing the routine logger location.
Requalify after any change to insulation thickness, liner, zipper, coolant geometry, divider or external dimensions.

General healthcare carriers are discussed in waterproof bags for medical equipment transport, but vaccines need a configuration-level qualification and release record. The core purchasing insight is simple: buy a reproducible packout, not a soft cooler plus accessories assembled from memory.

The 2–8°C band has a warm edge and a freeze edge

The familiar 2–8°C band has two hard boundaries. Warm exposure can accelerate potency loss, while freezing can irreversibly damage freeze-sensitive adsorbed vaccines. The cold-side hazard is often underestimated because operators equate colder with safer. A vial carton pressed against a −18°C water-ice pack can cross below 0°C locally even while a logger in the centre reports a compliant average. Thermal validation therefore needs spatial extremes, not merely a single central trace.

Observed condition	Immediate action	Why visual inspection is insufficient	Disposition in a strict programme
Logger stays 2.0–8.0°C and seals intact	Hold normal receiving review and archive the record	Cartons may look identical under every condition	Release only after all documentation checks pass
Any reading above 8.0°C	Quarantine, label excursion, stop onward distribution	Potency loss is invisible and re-cooling does not reverse it	Reject unless a named authority applies pre-approved stability data in writing
Any reading below 2.0°C or evidence of freezing	Quarantine and protect the trace	Freeze damage may occur without vial breakage	Reject under the strict no-excursion rule
Logger missing, stopped or serial mismatch	Treat temperature history as unknown	A cold-touch check cannot reconstruct the route	Reject or hold under the deviation procedure
Interior wet but trace compliant	Inspect containment, labels and packaging integrity	Meltwater damages secondary packs without changing temperature	Release product only if packaging and documentation criteria are met

This article uses a deliberately strict operational rule: any out-of-band reading means quarantine and shipment rejection. Some vaccine owners maintain product-specific stability data and may issue a written disposition after an excursion, but a carrier operator must never improvise that decision or average away a short peak. Returning an exposed carton to 5°C does not restore what warm exposure or freezing destroyed.

The wider distinction between waterproofing and temperature control is explored in thermal properties of waterproof materials. For procurement, place the 2.0°C and 8.0°C limits, logger accuracy and a no-rounding rule in the quality agreement so that a 1.9°C result cannot be reported as 2°C.

Map logger positions before declaring where the routine logger goes

Logger placement is a result of thermal mapping, not a convenient pocket chosen by the bag designer. Development trials should instrument the centre, upper corners, lower corners, wall-adjacent cartons, positions facing coolant and the region below the lid. Summer testing identifies the warm spot; winter and frozen-coolant testing identify the cold spot. A routine shipment logger is then placed at the justified worst-case payload position, commonly adjacent to representative product rather than attached to the outer wall or buried inside a coolant sleeve.

The sensing element must measure product-zone air or a justified thermal buffer, not PCM temperature. If the logger touches a frozen panel, it can show a false cold excursion that no vial experienced. If it sits in an insulated lid pocket, it may remain warm while product freezes below. Secure it so that it cannot migrate during vibration, and photograph the packed location before closure when chain-of-custody requirements justify the record.

Use calibrated loggers with accuracy appropriate to a narrow band; ±0.5°C is a common operational target, but the quality plan sets the requirement.
Choose a recording interval short enough to capture door openings and route peaks, often five minutes rather than thirty or sixty.
Synchronize clock, time zone and daylight-saving treatment before dispatch so the trace reconciles with custody events.
Record serial number, calibration due date, start status and alarm limits on the shipment record.
Provide a protected route for any probe wire, because a wire crossing the closure creates both an air leak and a water path.

A custom liner should include a flat, clearly marked logger retainer at the validated position and prevent workers from attaching it elsewhere. The acceptance drawing should dimension that retainer relative to the payload basket, not relative to a flexible outer panel. Chamber planning is covered in environmental testing for waterproof bags; the cold-chain protocol must add multi-point calibration and route-specific ambient profiles.

PCM grade and ice-pack conditioning decide the freeze risk

Coolant selection is the strongest design control for the cold boundary. Water ice changes phase near 0°C and may leave a −18°C freezer much colder than the allowable payload. A phase-change material formulated around 5°C can absorb heat near the vaccine band and reduce freezing risk, although it costs more and still needs controlled preconditioning. The word PCM does not guarantee a useful transition temperature: ask for the phase-change range, enthalpy, container dimensions, leak resistance and conditioning protocol.

Where programme guidance permits water-based ice packs, conditioning must be observable and timed. A common practice is to remove packs from the freezer and wait until liquid water is present and the surface condition matches the work instruction before loading. The necessary time varies with pack mass, freezer temperature and room conditions, so "leave out for thirty minutes" is not a universal control. Validate a measurable endpoint and use spacers that keep freeze-sensitive cartons from touching the pack.

Coolant approach	Thermal advantage	Primary failure mode	Procurement control
Frozen water pack	High latent heat and low unit cost	Local payload freezing and substantial meltwater	Validated conditioning endpoint, barrier spacer and leak-tested cap
5°C-class PCM panel	Transition centred near the vaccine range	Wrong grade or incomplete preconditioning shortens hold time	Name transition range, required conditioning state and lot traceability
Refrigerated gel pack	Flexible geometry and easy handling	Unknown formulation and inconsistent heat capacity	Require thermal data, leak resistance and cycle testing
Hybrid summer packout	Additional absorption at known warm zones	Operator swaps panel position and creates a cold spot	Keyed sleeves, numbered panels and a diagrammed sequence
Winter protection panel	Buffers sub-zero ambient from payload	Confused with active coolant during summer loading	Distinct shape and permanent identification, not colour alone

Specify total coolant mass and every panel position in the bill of materials. A generic "six ice packs" instruction permits substitutions in thickness, fill volume and freezing behaviour that invalidate qualification. Insulated carrier fundamentals appear in waterproof cooler bag design; the vaccine programme adds a controlled phase-change specification and a traceable conditioning step.

Meltwater inside the carrier is the dominant waterproofing load

For most vaccine routes, rain is a secondary water source. The routine liquid load is condensation on cold panels, frost melting after freezer removal, and leakage from repeatedly cycled ice packs. Several coolant units can release far more water than a passing shower, and that water stays trapped against the liner for hours. It attacks needle holes, bound corners, zipper terminations, label adhesives and corrugated secondary cartons, and it supports microbial growth in a compartment that is otherwise clean.

The construction response is a welded liquid compartment rather than a stitched liner: radiused corners, a seamless floor, a documented floor seam test, and a drainage or absorbent plan that does not wet the payload. A sealed coolant tray with a raised lip can contain the melt from several packs; a formed sump can be inspected and wiped after the route. Where the carrier must also resist rain, keep the two water paths separate, because rain on the exterior and meltwater on the interior require different barriers and different inspections.

Test the empty liquid compartment by holding the declared coolant melt volume overnight and inspecting every seam and corner afterwards.
Specify a smooth, wipeable interior with no exposed textile binding that can retain moisture and disinfectant residue.
Keep secondary cartons off the floor using a perforated rack, and confirm that perforations do not weaken the weld zone.
Place absorbent material where it cannot contact vial cartons, or the remedy can damage the documentation.
Dry the carrier fully after every route with lids and pockets open; a closed wet bag is a routine contamination source.

Seam verification methods are described in waterproof seam integrity testing. For cold-chain procurement, convert the selected method into a lot-acceptance test with sample count, dwell time and a zero-leak criterion applied to the welded floor and the zipper termination, which are the two locations where meltwater escapes first.

Payload zoning protects freeze-sensitive vials and paperwork

A validated packout separates the payload basket from coolant walls with a defined barrier. The barrier must be rigid enough to keep cartons from migrating against a frozen panel during vibration, yet open enough to allow air circulation where the thermal design depends on it. A flexible divider that collapses under braking can create both a freeze spot and a warm pocket in the same shipment. Document thickness, material and attachment method as part of the qualified configuration.

Secondary packaging, diluent cartons, documentation and the logger require deliberate locations. Dry documents and any barcode labels should be in a protected sleeve away from coolant. Vial trays should sit in a fixed orientation so that labels remain readable at delivery and any shake or vial break can be seen without unpacking every carton. If the carrier uses removable bins, key them so they cannot be installed in the wrong position, because an inverted bin can reverse the validated air path.

Define minimum distance from coolant surface to nearest carton and verify it after the longest route.
Use keyed or asymmetric bins so a tired operator cannot install them in an unvalidated orientation.
Keep documentation dry in a welded or coated sleeve with a readable window for scanning.
Provide a visible pack diagram inside the lid; the diagram is the control that survives staff turnover.
Specify void fill for partial loads, since a half-empty basket can warm and freeze faster than a full one.

Dimensions should be derived from real carton sizes plus closure headspace and barrier thickness, not from a nominal litre figure. The method for that conversion is set out in the size and dimension customization guide; the cold-chain addition is usable payload volume after insulation, barriers and coolant sleeves are installed.

Seasonal validation profiles replace a single comfortable test

A useful qualification uses a summer profile, a winter profile and, where applicable, a high-altitude or tropical profile instead of one pleasant laboratory day. The ISTA 7D family is widely used for insulated shipping containers precisely because it defines thermal profiles and sequence elements that approximate real distribution, including seasonal extremes and multi-day exposure. The standard is published by the International Safe Transit Association, and a protocol should cite the profile, duration, payload simulant and acceptance criteria explicitly.

Validation element	Summer profile intent	Winter profile intent	Acceptance evidence
Ambient exposure	High sustained heat, often with a solar-load proxy	Sub-zero ambient that can drive payload below 2°C	Time-series trace at every mapped payload point
Preconditioning	Coolant and payload at specified start states	Coolant near frozen but payload protected	Recorded preconditioning temperatures and times
Duration margin	Declared hold plus a safety margin, often 20–25%	Protection against cold ingress for the same duration	Warmest and coldest point within limits for full run
Handling sequence	Drop, compression and vibration within the sequence	Same sequence at cold material condition	No liner split, seam opening or divider collapse
Repeatability	At least three independent runs per profile	At least three independent runs per profile	Consistent worst-case position across runs

Repeat runs matter more than a single successful trace. Three independent runs per profile reveal whether the worst-case position is stable, and they expose packout variability that a single careful trial hides. Include deliberate imperfect packing in a supplementary trial: one pack left unconditioned, one spacer omitted, one logger in the wrong place. Those misuse runs quantify how much operator error the system tolerates before an excursion occurs.

Document the payload simulant. A block of foam has different thermal mass and conductivity from vaccine cartons, and a bottled-water simulant behaves differently again. Simulant choice is part of the qualified configuration, because a claimed 48-hour hold achieved with water can become a 20-hour hold with low-mass cartons.

WHO and good distribution practice define the documentation side

Packaging performance is only one half of a defensible programme. The other half is documented control: qualified equipment, trained personnel, calibrated monitoring devices, written procedures, deviation handling and records that can be reconstructed months later. Good distribution practice for pharmaceutical products and the WHO guidance on vaccine arrivals and temperature monitoring are published openly by the World Health Organization, and regional regulators publish equivalent GDP rules. The operational principle is consistent: if a control cannot be shown with a record, it did not happen.

Qualification protocol and report for each packout version, with profiles, simulants, logger positions and results.
Calibration certificates for loggers and for the reference thermometer used during mapping.
Training records keyed to the packout version, including the conditioning endpoint and seal check.
Deviation and excursion procedure with named decision authority and defined disposition paths.
Cleaning, drying and inspection records, plus repair and retirement rules for damaged carriers.
Change control: any material, coolant or divider change requires documented requalification.

The bag manufacturer can support this with evidence that sits inside its own scope: material data, weld process parameters, dimensional reports, seam test results, zipper cycle data and, where applicable, hygiene or material compliance documentation. What it cannot supply is the route-specific thermal qualification, because that depends on the packout, coolant and lane. Buyers should request the two evidence sets separately and avoid treating a material certificate as a cold-chain validation.

Commercial terms should protect the validated configuration, not merely the price. The clauses that matter in a carrier supply agreement are set out in our review of contract terms buyers should insist on, particularly material substitution control and traceability to a production lot.

Handling damage is a thermal failure waiting to be discovered

Physical damage and temperature failure are connected. A corner split after a curb drop lets warm air in and cold meltwater out; a collapsed divider puts vials against a frozen panel; a distorted zipper creates an air gap under the lid that no amount of coolant can offset. Distribution testing should therefore combine thermal exposure with drop, compression and vibration rather than testing insulation and strength separately.

A practical sequence conditions the packed carrier at the profile temperature, then applies drops on the corners and faces most likely to strike the ground, compression representative of stacked transit, and vibration for the expected road duration. Continue thermal monitoring through the sequence. Acceptance is not "the bag survived"; acceptance is that the liner did not split, the closure did not open, the divider did not collapse, and the trace stayed inside limits.

Drop the packed carrier, not an empty one, because coolant mass changes impact behaviour.
Inspect zipper terminations and floor-to-wall welds after the sequence; those are where splits begin.
Photograph any damage and keep it with the qualification report as the inspection benchmark for bulk lots.
Test stacked compression if carriers travel palletized; a bottom carrier can deform without an obvious external mark.
Re-run thermal duration after any handling change that alters insulation thickness or closure geometry.

The broader evidence framework for laboratory work is covered in third-party testing and certification. For vaccine carriers, add the requirement that the laboratory records preconditioning state, ambient profile, simulant description and logger calibration, because a certificate without those parameters cannot be compared between packouts.

Cleaning and drying routines must fit a wet cold compartment

A cold-chain carrier is repeatedly wet, repeatedly handled and often shared between sites, so cleaning and drying are part of the validated lifecycle. The liner must tolerate the approved detergent and disinfectant at the required wet contact time without cracking, hazing or softening. Printed pack diagrams and warning labels must survive the same cycles, because a faded instruction is an operational hazard. Aluminium and reflective layers inside an insulation stack must be protected, since aggressive chemistry can degrade reflective performance over time.

Define approved agents by active chemistry and concentration, not by a local brand that may change formulation.
Empty meltwater, wipe the sump and dry with every pocket and lid open before storage.
Validate print and label adhesion through the claimed number of cleaning cycles, not only at delivery.
Inspect coolant tray seams and cap threads during cleaning; small leaks become big melt loads.
Retire carriers with split liners, crushed insulation, distorted zippers or unreadable pack diagrams.

Drying is the step most often skipped, and it drives both microbial and odour problems. A closed cold compartment left wet overnight can develop biofilm in corners that a quick wipe will not remove. The cleaning procedure should therefore state a drying method, an inspection point and a sign-off, and the storage rule should keep carriers open or ventilated between routes.

Material compatibility with cleaning agents follows the same logic as industrial chemical exposure, discussed in chemical resistance of waterproof materials. Request coupon data for the specific disinfectant concentration and temperature used by the immunisation programme, including the effect on weld strength.

Instrumented route trials close the gap between lab and lane

Chamber qualification proves a packout under controlled conditions; route trials prove it under your conditions. A lane trial should use the real packing team, real coolant inventory, real vehicles, real dwell times and the actual logger model in the actual position. Instrument the worst-case summer and winter lanes and include the longest dwell, the worst traffic day and the least experienced packer. The objective is not another pass certificate but a measured margin and a list of practical failure modes.

Define acceptance before the trial: warmest and coldest mapped readings inside limits for the full lane plus margin; zero closure openings; zero liner damage; all labels scannable at delivery; packing time within the operational window; and no undocumented dwell. Record ambient outside temperature, vehicle type, shade or sun exposure, door-opening count and dwell location. If any run fails, treat the cause as a design or procedure change, then requalify rather than retraining around a fragile system.

Use a data logger per mapped position during trials; one logger cannot identify spatial extremes.
Photograph the packed configuration with the lid open before the first departure of each run.
Record coolant conditioning start and end times, plus freezer temperature, for each pack.
Include one intentionally late dispatch to quantify sensitivity to dwell outside the vehicle.
Keep the raw traces, not only a pass summary, because investigations need the shape of the curve.

A route trial also reveals ergonomics that laboratory work cannot: a lid that cannot be opened in a small vehicle, a divider that fights the packer, a logger pocket that is unreachable when the bag is full. Those frictions cause procedure drift, and procedure drift eventually causes an excursion. Our guide to custom bag sampling explains how to convert such findings into one controlled revision before bulk tooling.

Procurement controls that keep a validated packout from drifting

The most common cause of cold-chain failure is not a bad original design; it is drift. A coolant supplier changes pack wall thickness, a liner film is substituted, a divider is sourced from a different tool, or a print revision moves a panel number. None of these looks dramatic, and each can shorten hold time or create a cold spot. Procurement controls should therefore lock the configuration and make substitution a documented change event rather than a purchasing convenience.

Specify the qualified configuration by drawing and version: insulation thickness, liner material, weld method, divider geometry, hardware and label layout.
Require a material and process change notification clause, with requalification after any change to thermal or sealing parts.
Keep a signed golden sample, the qualification report reference and a controlled artwork file with revision identifiers.
Inspect incoming lots for insulation thickness, liner weld width, zipper function, divider dimensions and label legibility.
Plan variants through shared materials and controlled print versions; a different coolant system or liner is a different validation case.
MOQ is 500 pieces per style, so consolidate lane requirements into a small number of qualified configurations rather than many untested ones.

Inspection should separate cosmetic acceptance from critical acceptance. A shade variation or minor print registration issue can follow an AQL plan, but a liner leak, a split weld, a missing logger retainer, an unreadable pack diagram or a divider of the wrong thickness should be critical defects with zero acceptance. The framework in our AQL sampling guide can be adapted once those critical classes are defined.

For a new immunisation or distribution programme, send lane duration, ambient extremes, payload carton dimensions, coolant type and conditioning capability, logger model and acceptance criteria at enquiry. You can see how a carrier programme moves from application sample through validated sampling into bulk production; every style starts at 500 pieces minimum, with samples in 6–10 working days and bulk in 35–50 days, quoted FOB Xiamen.

Frequently Asked Questions

Q1. Why is a vaccine carrier qualified as a system rather than as a bag?

Because duration depends on coolant mass, phase-change temperature, preconditioning, payload thermal mass, dividers, closure and ambient profile. Changing any one of those can change hold time or create a cold spot, so the claim must attach to a versioned packout configuration.

Q2. What should happen after a temperature excursion?

Quarantine the shipment, label it, stop onward distribution, protect the logger trace and follow the deviation procedure. In the strict programme described here, any reading outside 2–8°C means rejection unless the responsible vaccine authority issues a written disposition based on product-specific stability data.

Q3. Is colder safer for vaccine transport?

No. Freeze-sensitive adsorbed vaccines can be damaged by freezing even when a centre logger reads a compliant value. Validation must map the coldest payload position and use barriers or spacers that keep cartons away from frozen coolant.

Q4. Where should the temperature logger be placed?

At the worst-case payload position identified during mapping, adjacent to representative product and not touching coolant or the outer wall. Development runs should instrument corners, lid zone and wall-adjacent cartons before the routine position is chosen.

Q5. What logger accuracy and interval are appropriate?

Accuracy appropriate to a narrow band, commonly around ±0.5°C, with a recording interval short enough to capture door openings and peaks, often five minutes. The quality plan should state the requirement and forbid rounding an out-of-band value.

Q6. How are PCM panels better than frozen water packs?

A PCM formulated near 5°C absorbs heat around the vaccine band and reduces local freezing risk. Water ice changes phase near 0°C and can leave a freezer far below the payload limit, so it needs validated conditioning, spacers and meltwater containment.

Q7. Why is meltwater a bigger waterproofing problem than rain?

Condensation, frost melt and leaking coolant packs can release litres of water inside the carrier for hours, attacking welded floors, zipper terminations, labels and cartons. Rain is external and intermittent; meltwater is internal, sustained and in contact with the payload zone.

Q8. What interior construction resists meltwater?

A welded liquid compartment with radiused corners, a seamless floor, documented seam testing, a raised coolant tray or sump, and a smooth wipeable liner with no exposed textile binding. Absorbent material must be placed where it cannot wet vial cartons.

Q9. What is ISTA 7D used for?

It is a widely used family of thermal transport profiles and sequences for insulated shipping containers, covering summer and winter extremes and handling elements. A protocol should cite profile, duration, simulant and acceptance criteria explicitly.

Q10. How many validation runs are needed?

At least three independent runs per profile is a sensible minimum, because repeatability shows whether the worst-case position is stable. Supplementary misuse runs, such as an unconditioned pack or an omitted spacer, quantify tolerable operator error.

Q11. What documentation does good distribution practice require?

Qualification protocol and report per packout version, logger calibration certificates, training records, cleaning and inspection logs, deviation and excursion procedures with named decision authority, and change control requiring requalification after material or coolant changes.

Q12. Can the bag supplier provide cold-chain validation?

It can provide material data, weld parameters, dimensional reports, seam and zipper testing and hygiene or compliance documents. Route-specific thermal qualification depends on packout, coolant and lane, so it remains the operator or brand responsibility.

Q13. How does handling damage affect temperature?

A corner split admits warm air, a collapsed divider pushes vials against frozen coolant, and a distorted zipper creates an air gap. Distribution testing should combine thermal exposure with drop, compression and vibration while monitoring continues.

Q14. What cleaning agents are safe for cold-chain liners?

Only those validated against the specific liner, print and weld. Define agents by active chemistry and concentration, validate print adhesion and weld strength through the claimed number of cycles, and dry the carrier fully with pockets open after every route.

Q15. What are critical defects at incoming inspection?

Liner leak, split weld, missing or relocated logger retainer, unreadable pack diagram, wrong divider thickness and non-functioning closure. These should have zero acceptance, while minor cosmetic issues can follow an AQL plan.

Q16. What is the MOQ for custom vaccine cold chain bags?

MOQ is 500 pieces per style. Consolidate lanes into a few qualified configurations and vary documentation or print rather than insulation, liner or coolant geometry, because a different thermal construction is a separate validation case.

Waterproof Vaccine Cold Chain Transport Bags for 2–8°C Distribution