The file for a multi-compartment body rests on two documents. The first is the ATP certificate, the second is the declaration of conformity that footnote 4 of the certificate asks for. The footnote defines multi-temperature equipment as insulated equipment with two or more compartments, each held at its own temperature, and requires the declaration to travel with the certificate. If only the certificate is in the file, the set is incomplete.
What the declaration contains
The declaration follows the 'Conformity declaration' block in section 7.3 of Annex 1, Appendix 2 and the Model No. 14 layout. The footnote and the Model No. 14 heading both cite that block as 7.3.6. The block asks for at least two things: a sketch of the real compartment and evaporator arrangement, and a calculation showing that the equipment meets ATP for the freedom the user wants in compartment temperatures and sizes. Model No. 14 asks for the dividing wall positions, the movable walls, the position of the host unit and evaporators, the floor material and the ATP test report numbers.
The calculation section requires that the wall positions be scanned from the smallest compartment to the largest, with no step changing the inside surface area by more than 20%. A position that has not been scanned counts as not dimensioned. If you set the wall at a position outside those checked, the paper in your hand does not describe that body.
Both the paperwork and the test change once a second compartment appears, so our multi-temperature distribution page gathers how the regimes get shared out inside one vehicle.
The K values of the dividing walls are given in ATP 7.3.7 (W/m²K):
| Wall | Fixed | Movable | Minimum insulation (mm) |
|---|---|---|---|
| Longitudinal, aluminium floor | 2.0 | 3.0 | 25 |
| Longitudinal, GRP floor | 1.5 | 2.0 | 25 |
| Transversal, aluminium floor | 2.0 | 3.2 | 40 |
| Transversal, GRP floor | 1.5 | 2.6 | 40 |
Calculation example. The first step is the heat gain through the outer body and the minimum capacity of the unit. Under ATP the nominal capacity must be at least 1.75 times the product of the body's K value, the geometric mean of its inside and outside surface areas (S) and the temperature difference between outside and inside. Example (an assumption, not a measured value): K = 0.40 W/m²K, S = 40 m², outside +30 °C, inside -20 °C, difference 50 K. Result: 1.75 × 0.40 × 40 × 50 = 1,400 W. In this body the unit must give at least 1.4 kW of nominal capacity. The factor 1.75 comes from paragraph 3.2.6 of Annex 1, Appendix 2.
The load of a dividing wall follows the same logic. Example: a 1.5 m² longitudinal wall with a 20 K difference between two compartments (0 °C and -20 °C). With a fixed wall (K = 2.0) the heat gain is 1.5 × 2.0 × 20 = 60 W; if the same wall is movable (K = 3.0) it is 90 W. A movable wall brings 50% more heat than a fixed one, and that difference belongs in the calculation.
The mark: FRC-FRA and FRC-M
The mark on the body reflects the compartment layout in the calculation. Under ATP Annex 1, Appendix 4, a road body divided into two compartments carries the marks of both compartments, starting with the compartment at the front or on the left: FRC-FRA. With more than two compartments only the mark of the highest ATP class is taken and the letter M is added: FRC-M. The 'Is approved as' line of the certificate carries one or more descriptions and their marks, as footnote 7 requires.
| Mark | Meaning | Ti range |
|---|---|---|
| FRA | Mechanical refrigeration, heavy insulation, class A | +12 °C to 0 °C |
| FRC | Mechanical refrigeration, heavy insulation, class C | +12 °C to -20 °C |
| FRF | Mechanical refrigeration, heavy insulation, class F | Fixed at -20 °C or below |
In FRC-FRA the compartment at the front or on the left is class C and can go down to -20 °C; the rear compartment is class A and is held between 0 °C and +12 °C. In Türkiye the same mark is used on the perishable food transport document: article 15 of the Ministry of Transport and Infrastructure regulation puts a red 'T-' in front of the mark and states that goods carried under FRC may be carried under T-FrC. The mark therefore also tells you which product may go into which compartment.
The periodic test measures the compartments together. ATP 6.2.2 (iii) requires the test in (i) to be carried out for all compartments at the same time. If the walls move, the compartment volumes are set to match the highest cooling demand. The measurement runs until the warmer of the two sensors inside each compartment reaches the class temperature. The time limit comes from the table; the lower of the two mean outside readings, meaning the colder one, is used, so the test is set against the harder of the two figures.
Where compartment temperatures can be changed, a reversibility test follows. Some compartments are taken to -20 °C, others to 0 °C, and then the settings swap. A compartment that has moved to 0 °C must hold 0 °C ± 3 °C for at least 10 minutes while its neighbours stay at -20 °C. On a body with a heating function the test runs with the doors shut and no time limit; on a body without heating the compartment doors may be opened to speed up the temperature rise.
Unconditioned compartment
ATP 7.1 (d) defines an 'unconditioned compartment' as one with no evaporator, or with an inactive one. In the calculations this compartment enters at +20 °C (7.3.3), and insulated compartments are also given +20 °C in 7.3.4. An unconditioned compartment is therefore not counted as a second cold zone; it loads the other side of the wall as a +20 °C load. If you want a second cold regime, an evaporator goes into that compartment and the declaration is recalculated for its position and the wall positions. The declaration has to hold for every wall position and every temperature distribution.
Four checks when you open the file
- If the MULTI-TEMPERATURE box at the top of the certificate is ticked, the declaration must be in the file.
- Does the sketch match the bulkhead and evaporator arrangement in the body? If not, the declaration describes another body.
- Has every position of a movable wall that you use been scanned in the declaration? A position not scanned counts as not dimensioned.
- Does the 'Is approved as' line show the marks of both compartments? If you see a single class code on a two-compartment body, ask about it.
If the declaration is missing, ask the bodybuilder who sold you the unit or your supplier. For Isotec equipment, send the document request to Aris Makina; we obtain the paperwork from GEBHARDT and pass it on to you.
