Triple packaging

The five numbers

On this page11

95 kilopascals Which is an altitude requirement And note the or 1.2 metres Which is roughly waist height on a loading dock 100 mm by 100 mm Which exists so the markings fit One litre and four litres, by aircraft Which caps the primary receptacle at a litre Four numbers test the system, one caps the bottle References

All five are tests on an assembly, which is why a bottle cannot pass them alone.

95 kilopascals

"The primary receptacle or the secondary packaging must be capable of withstanding without leakage an internal pressure producing a pressure differential of not less than 95 kPa."

Which is an altitude requirement

It is there because the parcel may fly, and a sealed container at altitude is holding a pressure difference against the cabin or the hold. A closure that seals on a bench may not.

And note the or

The primary receptacle OR the secondary packaging. One of the two has to hold it, which is a design choice about where the containment lives.

1.2 metres

"The packaging must be capable of successfully passing the drop test in 178.609(d) of this subchapter at a drop height of at least 1.2 meters (3.9 feet)."

Which is roughly waist height on a loading dock

A realistic drop rather than a severe one, and the test is of the whole packaging with the inner layers inside it.

100 mm by 100 mm

"At least one surface of the outer packaging must have a minimum dimension of 100 mm by 100 mm (3.9 inches)."

Which exists so the markings fit

The UN3373 diamond and the proper shipping name need a surface to go on. A parcel too small to carry the mark legibly is a parcel nobody can identify.

One litre and four litres, by aircraft

Each primary receptacle may not exceed 1 L, and each outer packaging may not exceed 4 L, for liquids. For solids the outer may not contain more than 4 kg, excluding body parts and organs.

Which caps the primary receptacle at a litre

And our shelf tops out at 946 mL, so capacity is one requirement the containers here happen to sit inside. That is a coincidence rather than a design.

Four numbers test the system, one caps the bottle

Which is the summary. Pressure, drop and dimension belong to the assembly; the volume limit is the only one a container supplier can speak to directly.

References

49 CFR 173.199, Category B infectious substances. "A Category B infectious substance must be packaged in a triple packaging consisting of a primary receptacle, a secondary packaging, and a rigid outer packaging." Absorbent material "must be placed between the primary receptacle and secondary packaging" and "must be of sufficient quantity to absorb the entire contents of the primary receptacles". "The primary receptacle or the secondary packaging must be capable of withstanding without leakage an internal pressure producing a pressure differential of not less than 95 kPa." "The packaging must be capable of successfully passing the drop test in 178.609(d) of this subchapter at a drop height of at least 1.2 meters (3.9 feet)." "At least one surface of the outer packaging must have a minimum dimension of 100 mm by 100 mm (3.9 inches)." By aircraft, each primary receptacle may not exceed 1 L and each outer packaging 4 L for liquids, or 4 kg for solids. law.cornell.edu

The Davis Pack Supply catalog, measured 19 October 2026. The diagnostics and lab shelf is 600 rows: 270 containers and 330 closures. 5 mL to 946 mL with a median of 118; 71 containers at 30 mL or under, 105 at 60 or under, 154 at 120 or under, 248 at 500 or under. 154 HDPE, 103 glass, 13 PP, and no PET. 246 bottles, 19 jars, 3 jugs, 2 tubes. 97 white, 57 natural, 35 clear, 28 amber. Closures: 163 continuous thread, 44 child resistant, 32 dropper assemblies, 27 spouted, 19 flip top, 14 phenolic, 7 buttress, 6 specialty, 5 dome lids.

Written from 49 CFR 173.199 and 173.134, and from the catalog as it stood on 19 October 2026. Nothing here is offered as a compliant primary receptacle for a regulated shipment: the pressure and drop requirements attach to a tested assembly, not to a bottle. Category A infectious substances are a different packaging instruction entirely and are not summarized. Sterility is not claimed for any product, and what a laboratory will accept is the laboratory's to say.