This feature article discusses the humble overpack in its various forms and the requirements for its labelling and marking.
The overpack is much maligned and viewed with some mistrust by many freight forwarders as having a potential for hidden hazards. In this article, an attempt is made to explain the various forms of overpack and the requirements for its labelling and marking.
So what is an overpack and what are the shippers, consignors and packers responsibilities?
An overpack is defined by the UN Model Regulations as “an enclosure used by a single consignor to contain one or more packages and to form one unit for the convenience of handling and stowage during transport”.
An example of an overpack is a number of packages placed or stacked onto a load board or tray such as a pallet and secured by strapping, shrink-wrapping, stretch-wrapping or other suitable means, as shown in Figures 1 and 2, or single receptacles placed into a protective outer packaging such as a box, as in Figure 3 below.
Requirements for packages within overpackages
First, each dangerous goods package within the overpack must be packed, assembled, marked and labelled in complete compliance with the transport regulations.
The packages must be correctly orientated within the overpack and the intended function of any package should not be impaired by the overpack. The packages must also be secured to prevent movement within the box or crate to avoid damage.
All packages within the overpack must be inspected for any signs of contamination and dangerous residues adhering to their outside surfaces and to ensure that there are no signs of damage, corrosion or reduced strength (creasing of fibreboard, etc). Any package not complying with the above should be removed from the overpack.
Incompatible dangerous goods that require prohibition on mixed loading in accordance with ADR Chapter 7.5.2 for road transport or segregation in the case of the IMDG Codes Chapter 7.2 for sea transport should not be placed within the same overpack.
Marking and labelling of overpacks
Road and sea carriage will be dealt with separately due to the slight but important differences imposed on the consignors by the different surface regulations.
ADR/RID part 5, Chapter 5.1.2 requires that an overpack:
shall be marked with the word “overpack” in the official language of the country of origin. If that language is not English, French or German, then it must be marked in English, French or German as well, unless agreements between countries provide otherwise; the overpack marking shall be at least 12mm high
shall be marked with the UN number proceeded by the letters “UN” as required for each substance contained within the overpack; there is no requirement to apply the proper shipping name (PSN) to the overpack for UN Class 1 and 2 as per ADR/RID 22.214.171.124 or 126.96.36.199
should bear the environmentally hazardous mark if applied to the packages as per 188.8.131.52 of ADR/RID
orientation arrows must be displayed on two opposite sides when packages which are contained within the overpack are marked in accordance with ADR/RID 184.108.40.206 and display the orientation marks; the packages bearing the markings as prescribed in ADR/RID 220.127.116.11 must be orientated in accordance with such markings within the overpack.
Strangely, ADR/RID seems, therefore, to permit single drums of dangerous liquids to be placed inside overpacks without orientation arrows on the overpack, since single packagings do not need orientation arrows as the closure is visible. This anomaly has been referred to the UK Expert to ADR/RID. The author recommends that overpacks containing single packagings of dangerous liquids do bear appropriately orientation arrows.
This is necessary unless the UN numbers, the labels and the environmentally hazardous marks representative of all the dangerous goods contained within the overpack are visible. If the same UN numbers, labels or environmentally hazardous mark are required for different packages, they only need to be applied once (see Figure 4 below).
Sea (IMDG Code)
IMDG Code, Part 5, Chapter 5.1.2 requires that an overpack:
shall be marked with the PSN and the UN number proceeded by the letters “UN” and marked and labelled as required by 5.2 for each substance contained within the overpack
shall be marked as per 5.2 with orientation arrows as per 18.104.22.168 on two opposite sides and the special marking for marine pollutants when in accordance with 22.214.171.124.3
marked with the word “overpack”, the overpack marking shall be at least 12mm high
each package bearing orientation arrows in accordance with 126.96.36.199 shall be correctly orientated within the overpack.
See Figure 5 below.
This is necessary unless the UN numbers, marks and labels representative of all the dangerous goods contained within the overpack are visible.
Limited quantities overpack
When dangerous goods are packed in accordance with Chapter 3.4 of the surface regulations they are required to be marked with the limited quantity (LQ) mark and the word “overpack” unless an LQ marking is visible. See Figure 6 below.
ADR will require the word “overpack” to be in the language of the country of origin (see ADR/RID above), and if not in English, French or German, then also in one of English, French or German.
IMDG will require orientation arrows on two opposite sides of the overpack when packages within the overpack comply with 188.8.131.52 of the IMDG Codes.
Overpacks containing dangerous goods packed in LQs and those which are not packed as LQs must display all required marks and labels.
Excepted quantities overpack
When dangerous goods are packed in accordance with Chapter 3.5 of the surface regulations, they are required to be marked with the excepted quantity (EQ) mark unless markings representative of all the dangerous goods in the overpack are visible. See Figure 7 below.
Although, none of the surface regulations stipulate that the use of an overpack shall be entered on the transport document, the overpack is part of the packing arrangement and an entry should be considered by the consignor/shipper in the number and description of packages entry, see examples below.
Example 1 Road (ADR Chapter 5.4)
UN 1230, Methanol, 3 (6.1), PG II, (D/E)
4 x cage pallets each containing 12 plastic jerricans (3H1)
Example 2 Sea (IMDG Code Chapter 5.4)
UN 1950, Aerosols, Class 2.1, “limited quantities”
1 x wooden pallet containing 35 fibreboard boxes
Each containing 10 × 600ml Aerosols
An overpack, when correctly used, can often simplify the loading of cargo transport units by speeding up the handling, stowage and restraint of cargo. It can also offer extra protection to the articles and substances being transported, and assist in the safety of those involved.
However, the consignors/shipper must verify that:
the dangerous goods are packed, marked and labelled in accordance with the regulations
the packages are free from damage and secured so they will not be damaged during the normal conditions of handling, stowage and carriage
any articles or substances that require segregation or are subject to mixed loading prohibitions are removed
all marking and labelling required by the modal regulations, if not visible, has been correctly applied and affixed to the overpack
an indication on the transport document that an overpack has been used and the correct number and type indicated to aid freight forwarders and carriers with the accurate calculation of shipments weights.
Illustrations and photographs supplied by A Shylan and used with his permission.
Last reviewed 16 December 2019