Freight equipment

Refrigerated Trailer

A refrigerated trailer is an insulated body with its own temperature control unit. The critical thing to understand is that it maintains a temperature rather than creating one.

Mode: Road
Published figures: 14, each with a named publisher

A tractor unit coupled to an unmarked refrigerated box semi-trailer, standing on a hard surface in daylight.

What a refrigerated trailer is doing

A refrigerated trailer, commonly called a reefer, is an insulated box with a refrigeration unit mounted at the front that runs independently of the tractor. The unit is set to a target temperature and works to hold the air inside the body at that setting for the duration of the journey.

Some units can heat as well as cool, which matters on routes where the risk is freezing rather than warming. Multi-temperature bodies exist, divided into compartments held at different settings, and they suit mixed loads at the cost of complexity and usable space.

It maintains temperature, it does not create it

This is the single most important point about the equipment and the most frequently misunderstood. The refrigeration unit is sized to hold a load at temperature against heat coming through the walls and doors. It is not sized to pull a warm pallet of goods down to a target.

Goods loaded above their required temperature will generally stay above it for a long time, and may not reach the setting at all before arrival. The product has to be at temperature when it is loaded, brought there in the producer's own chilling or freezing equipment, not in a trailer.

The trailer itself should be pre-cooled before loading, and dock time kept short, because every minute the doors stand open at an ambient loading bay is heat entering a body the unit then has to remove.

Airflow does the work

The unit conditions air and circulates it. Whether that air actually reaches the goods is decided by how the trailer is loaded, and a well-run unit in a badly stacked trailer will not deliver the temperature the paperwork claims.

Air has to move over the load and return to the unit. That means not packing tight to the roof, not blocking the return path at floor level, and not stacking against the walls in a way that seals off the circulation. Grooved or channelled floors exist precisely so air can travel underneath, and pallets that cover them defeat the design.

The consequence of getting this wrong is uneven temperature: goods at one end of the load within specification and goods at another outside it. In a temperature-controlled consignment, part of the load being out of specification is normally treated the same as all of it.

The chain, not the leg

The trailer is one link. Cargo that is correctly conditioned in transit and then left standing on an ambient dock at either end has still been through a temperature excursion, and the record will show it. The plan has to cover loading, the run, any transhipment and unloading, not just the part with the refrigeration unit attached.

Recording is part of that. Temperature-controlled movements are normally accompanied by a record of the conditions during the journey, and the setting on the unit is not the same thing as the temperature of the product. Which records are required, and what tolerances apply, are set by the commodity and the receiving party.

Hygiene and food-safety regimes, restrictions arising from what the trailer previously carried, and the rules applying to pharmaceutical and other regulated goods vary by jurisdiction and by commodity. They must be confirmed for the specific consignment with the relevant authority or the party imposing the requirement.

Suited to

What this equipment is for.

Chilled and frozen foodstuffs that are already at their required temperature when loaded
Goods with a defined temperature specification that must be evidenced on arrival
Products at risk from freezing on cold routes, where a unit able to heat protects the load
Mixed consignments needing more than one temperature, where a compartmented body is available
Flows where both the loading and receiving sites have temperature-controlled docks
Cargo whose value or shelf life justifies the additional cost of controlled transport

Specifications

Published figures, and who publishes them.

These are not industry constants. Each figure below is one named publisher’s statement about its own equipment on the date it was checked, and where publishers disagree the row says so. For a specific shipment, the specification that matters is the one for the actual vehicle or container being used.

Internal length: 13,310 mmVerbatim 'Internal length | 13310 mm' for type SDR 27 eL4-S — 310 mm SHORTER than the same builder's 13,620 mm dry box, because insulated end walls and the front-mounted refrigeration unit eat internal length. Schmitz's S.KO COOL SMART publishes a different set again: '13.4 / 14.7 / 16.8 m'. This is the field where quoting one number would be most wrong.Krone (Fahrzeugwerk Bernard Krone GmbH & Co. KG) — source, checked 2026-08-14
Internal width: 2,460 mmVerbatim 'Internal width | 2460 mm' — 20 mm narrower than the same builder's dry box (2,480 mm) because of the insulation. Schmitz publishes 'Intenal body width* | 2,460 or 2,490 | mm' with its own footnote '* depending on the statutory requirements and the individual semi-trailer specification'; the 2,490 mm variant is available because 96/53/EC Annex I 1.2(b) allows conditioned vehicles 2.60 m external width instead of 2.55 m.Krone (Fahrzeugwerk Bernard Krone GmbH & Co. KG) — source, checked 2026-08-14
Internal height: 2,630 mmVerbatim 'Internal height | 2630 mm' for SDR 27 eL4-S. Schmitz publishes a range across its reefer family instead: 'Internal body height* | 2,350-3,050 | mm', footnoted as depending on statutory requirements and the individual specification. Insulated roof and floor plus the 4.00 m limit (96/53/EC Annex I 1.3) are what compress this figure relative to a curtainsider.Krone (Fahrzeugwerk Bernard Krone GmbH & Co. KG) — source, checked 2026-08-14
Euro pallet capacity: 33 / 36 / 41 (Euro pallets); 26 (ISO pallets) palletsVerbatim 'Pallet spaces | 33 / 36 / 41 | Euro pallets or 26 ISO pallets', printed directly against 'Internal body length | 13.4 / 14.7 / 16.8 | m' — so here the three-to-three mapping IS readable (33 for the 13.4 m body). Note 33 for a reefer versus 34 for Schmitz's own dry box: insulation costs a pallet. Same footnote applies about statutory requirements and individual specification.Schmitz Cargobull — source, checked 2026-08-14
Tare weight, excluding refrigeration unit: 7,630 kgVerbatim, and the parenthesis is Krone's own: 'Tare weight (without cooling unit) | 7630 kg'. The delivered trailer is heavier by the weight of the fridge unit, which Krone does not state — so a payload figure MUST NOT be derived from this by subtracting from the 39,000 kg permissible total weight. Krone publishes no payload row for this model and Schmitz publishes no weights at all for its reefers; see the refused list.Krone (Fahrzeugwerk Bernard Krone GmbH & Co. KG) — source, checked 2026-08-14
Temperature-control certification: ATP Class FRC or FNA (no numeric temperature range published) classVerbatim: 'Our trailers comply with ATP Class FRC or FNA, depending on the application and equipment options'. Included because it is the honest alternative to inventing a temperature range: the class is the sourced fact, the °C figures are not on this page. ATP is the UN agreement on perishable foodstuffs transport, and the class achieved depends on the specification ordered.Schmitz Cargobull — source, checked 2026-08-14
Load securing, EN 12642 Code XL: Certified as standard by Schmitz and Krone on curtainsiders; optional on Kögel platform bodies certificationThree separate verbatim confirmations, and the difference between them matters: Schmitz — 'DIN EN 12642 Code XL. Certified structural rigidity as standard.'; Krone data sheet — 'load security certificate according EN 12642 Code XL'; Kögel platform page — 'Optionally with certification according to EN 12642 XL (VDI 2700)'. So XL is standard on mainstream curtainsiders but an ORDERED OPTION on platform bodies. A page must not state that any given trailer arriving on a job is XL-certified — that is a per-vehicle fact, and the EC guidelines say the load capability should be marked on the vehicle and that if no mark can be seen it must be assumed the curtain has no load-bearing function.Schmitz Cargobull / Krone / Kögel — source, checked 2026-08-14
Side wall strength, EN 12642 XL: 40 (0.4 P), distributed over the length and at least 75% of internal sidewall height % of payloadFrom the English PDF of 'Cargo securing for road transport — 2014 European best practices guidelines' (ISBN 978-92-79-43665-9) downloaded from this record, around pp. 16-18. Verbatim: 'If the side walls are built according to EN 12642 XL the side walls are tested to take up a force corresponding to 40 % of the payload (0.4 P) uniformly distributed over the length and at least 75% of internal height of the sidewall.' Companion values on the same pages: XL headboard 50 % (0.5 P), XL rear wall 30 % (0.3 P); the lower Code L grades are headboard 40 % max 5,000 daN, side walls 30 %, rear wall 25 % max 3,100 daN. Critically, the guidelines state that 'side walls in a curtainsider built according to EN 12642 L is regarded as a weather protection only'. The guidelines are not legally binding; the EN standard text itself is paywalled by CEN and was not consulted.European Commission, Directorate-General for Mobility and Transport — source, checked 2026-08-14
Lashing point placement (EN 12640): in pairs opposite each other; 0.7–1.2 m longitudinal spacing; max 0.25 m from the outer edge mVerbatim from the same 2014 EC publication (around p. 21): 'Lashing points in load carriers should be placed in pairs, opposite each other, along the long sides with a spacing of 0.7 – 1.2 m longitudinally and a maximum of 0.25 metres from the outer edge. Continuous lashing anchorage bars are preferable.' This is the answer to 'number of load securing points where standardised': the standard fixes SPACING and STRENGTH, not a count — so no count may be published as standardised. Builders differ within it (Krone's Multi Lock rave offers positions every 100 mm, far denser than the minimum).European Commission, Directorate-General for Mobility and Transport — source, checked 2026-08-14
Lashing point strength (EN 12640): 800 (3.5–7.5 t); 1,000 (above 7.5–12.0 t); 2,000 (above 12.0 t), 4,000 generally recommended daNTable 3 of the same publication, reproduced verbatim including its asterisk: 'Vehicle total mass in tonnes / Strength of lashing point in daN — 3.5 to 7.5 : 800; above 7.5 to 12.0 : 1.000; above 12.0 : 2.000* *(in general 4.000 daN is recommended)'. For any semi-trailer in scope here only the 'above 12.0 t' row applies. The guidelines add that 'Lashing points in sound condition on a vehicle in sound condition are considered to meet the requirements ... even if no certificates are available', which is a condition-dependent presumption, not a guarantee.European Commission, Directorate-General for Mobility and Transport — source, checked 2026-08-14

EU legal maximum

Maximum height: 4.00 mAnnex I, point 1.3, applying to any vehicle. This is the ceiling that produces the mega-trailer design: 4.00 m overall minus tyres, chassis and roof leaves the ~3.00 m internal height Krone quotes. National derogations exist — Article 4(2) permits member states to allow vehicles in NATIONAL transport that deviate from point 1.3 among others, which is why higher combinations run lawfully in some states and not across borders. EUR-Lex consolidated texts are documentation tools with no legal effect; only the Official Journal versions are authentic.European Union — Directive 96/53/EC, consolidated text (EUR-Lex) — source, checked 2026-08-14
Maximum width: 2.55 (general); 2.60 (conditioned vehicles) mAnnex I, point 1.2: (a) all vehicles except conditioned vehicles 2.55 m; (b) superstructures of conditioned vehicles or conditioned containers/swap bodies 2.60 m. The extra 50 mm for conditioned bodies is precisely what allows a reefer to reach 2,490 mm internally despite insulated walls, and explains Schmitz's '2,460 or 2,490 mm'. Consolidated text — see the authenticity caveat above.European Union — Directive 96/53/EC, consolidated text (EUR-Lex) — source, checked 2026-08-14
Maximum length, articulated vehicle: 16.50 mAnnex I, point 1.1 (articulated vehicle); a road train is 18.75 m. Together with point 1.6 — maximum distance from the fifth-wheel kingpin axis to the rear of a semi-trailer, 12.00 m — this is why 13.62 m is the near-universal European internal length. Point 1.5 additionally requires the combination to turn within a swept circle of 12.50 m outer / 5.30 m inner radius. Consolidated text; national derogations under Article 4.European Union — Directive 96/53/EC, consolidated text (EUR-Lex) — source, checked 2026-08-14
Maximum weight, combination: 40 t (five/six-axle articulated); 44 t (three-axle tractor + two/three-axle semi-trailer in intermodal transport with containers/swap bodies up to 45 ft); 42 t (two-axle tractor + three-axle semi-trailer, same intermodal case) tonnesAnnex I, point 2.2.2 (a)-(d). This is the number that makes every manufacturer payload figure above non-bookable, and it is the one regulatory fact an equipment page cannot omit: the 40 t covers tractor + trailer + load. The 44 t and 42 t figures apply ONLY to the intermodal container/swap-body case described in the text and must not be quoted as a general road limit. Member states may permit deviations in national transport under Article 4(2), so cross-border and domestic limits differ.European Union — Directive 96/53/EC, consolidated text (EUR-Lex) — source, checked 2026-08-14

Considerations

What constrains it.

Product must be at temperature before loading; the unit holds a temperature and does not bring goods down to one
Pre-cool the trailer and keep door-open time at the dock as short as the operation allows
Stacking decides whether air reaches the goods — leave the return path clear and do not block floor channels
The setting on the unit is not the product temperature, and receiving parties usually care about the second
A break in the chain at either dock counts as an excursion even if the run itself was correct
Previous-load restrictions and cleaning requirements may apply, particularly for foodstuffs
Applicable hygiene, food-safety and pharmaceutical requirements vary by jurisdiction and commodity and must be confirmed per consignment

From equipment to load plan

Confirm the unit against the actual cargo.

Suitability depends on the goods, loading method and the specification of the equipment that will actually be used.

European road freight