Infectious Substances in Practice: Packing Instruction 620 and Packing Instruction 650

Infectious Substances in Practice: Packing Instruction 620 and Packing Instruction 650

Classifying an infectious substance as Category A or Category B decides which of two very different packing regimes applies. Packing Instruction 620 governs Category A and is one of the most demanding instructions in the manual. Packing Instruction 650 governs Category B and is deliberately accessible, because it is used daily by clinics and laboratories with no dangerous goods specialists on staff. Both are built on the same triple packaging principle.

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1. The Triple Packaging Principle

Every infectious substance package, in either category, has three layers:

   +-----------------------------------------------------------+
   |  OUTER PACKAGING  (rigid, min. dimension 100 mm)           |
   |   +---------------------------------------------------+   |
   |   |  SECONDARY PACKAGING  (leakproof, watertight)      |   |
   |   |   +-------------------------------------------+   |   |
   |   |   |  PRIMARY RECEPTACLE (leakproof, watertight)|   |   |
   |   |   |  The specimen itself                       |   |   |
   |   |   +-------------------------------------------+   |   |
   |   |   Absorbent material: enough to absorb ALL liquid  |   |
   |   +---------------------------------------------------+   |
   |   Itemised list of contents between secondary and outer   |
   +-----------------------------------------------------------+

Three requirements are common to both instructions and are examined repeatedly:

• Absorbent material must sit between the primary receptacle and the secondary packaging, in a quantity sufficient to absorb the entire liquid contents of all primary receptacles.
• The primary receptacle or the secondary packaging must withstand an internal pressure differential of not less than 95 kPa, maintained across the temperature range -40°C to +55°C.
• The outer packaging must have a minimum external dimension of 100 mm, so that the marks and labels can be read.
• An itemised list of contents is enclosed between the secondary packaging and the outer packaging.

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2. Packing Instruction 620 — Category A

Category A covers substances capable of causing permanent disability, or life-threatening or fatal disease, in otherwise healthy humans or animals: UN 2814 (affecting humans), UN 2900 (affecting animals only) and UN 3549 (Category A medical waste).

The 9 metre drop test is the figure to remember: it is far above the 1.8 m used for Packing Group I chemical packagings, because the consequence of release is biological rather than chemical.

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3. Packing Instruction 650 — Category B

Category B is everything infectious that does not meet the Category A criteria — the routine diagnostic specimen. It is assigned to UN 3373, Biological Substance, Category B.

A PI 650 consignment that fails any condition of the instruction is no longer a PI 650 consignment. It reverts to being fully regulated, which for a Category B substance means it can no longer be offered at all in that condition and must be repacked correctly.

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4. Refrigerants and the Common Error

Diagnostic specimens are usually shipped cold, so an infectious substance package very often also contains a refrigerant:

• Dry ice (UN 1845) — the outer packaging must permit the release of carbon dioxide gas, and the dry ice must be placed outside the secondary packaging so that the secondary packaging is not crushed as the specimen contracts. The package is marked with the net mass of dry ice and the Class 9 label, and dry ice must be declared on the Air Waybill.
• Liquid nitrogen (UN 1977) — additional requirements apply, including the use of a receptacle designed for the temperature and the retention of any liquid.

The most common practical error is packing the coolant inside the secondary packaging. It must sit between the secondary and the outer packaging, with the secondary packaging supported so that it stays in position once the coolant has sublimated or evaporated away.

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5. Deciding Between the Two

The decision is made on the classification, never on convenience or cost:

1. Does the substance meet the Category A criteria — capable of causing permanent disability, life-threatening or fatal disease in otherwise healthy humans or animals? → Category A, UN 2814 / UN 2900 / UN 3549, Packing Instruction 620, full declaration.
2. If not, is it still known or reasonably expected to contain pathogens? → Category B, UN 3373, Packing Instruction 650, no declaration.
3. Is it a patient specimen with minimal likelihood of pathogens, or a substance that has been neutralised or is otherwise excluded? → It may fall outside Division 6.2 altogether; verify against the Section 3 exclusions before deciding.