（UN 3077, UN 3082, UN 3334 and UN 3335 show a maximum net quantity for PAX/CAO packing instructions but for LTD QTY, only 30jg G is shown. Why is it so?）
For Environmentally hazardous substances （UN3082/UN3077）, PAX/CAO PI indicates the permissible net quantity per package however for LTD QTY, 30kg G is shown as the weight limitation.
Likewise for Aviation regulated liquid/solid n.o.s. （UN3334/UN3335） the net quantity limitations are shown for PAX/CAO, but for LTD QTY the limitation is 30kg G. While my understanding is that the quantity will be shown in gross weight terms particularly for articles, I miss why these substances are indicated in gross weight terms for LTD QTY.
Does this have something to do with the introduction of PI Y963 to apply for all LTD QTY/PAX/CAO shipments of ID 8000 Consumer Commodity to allow intermodal transport? I would also wish to reconfirm UN’s approach regarding the transport of LTD QTY shipments for other modes of transport.
By introducing the letter Y in a diamond Mar ing for LTD QTY shipments, other modes of transport have accepted the transport of LTD QTY. Thus hitherto ID 8000 Consumer Commodity shipments which had to be re Dec ared at the intermodal transfer point by re Dec aring the shipment into each applicable class/division, UN made a seamless intermodal transport possible. I would appreciate comments and advice. (30 Jun 12)
The UN Model Regulation as well as IMO’s IMDG、and UN ECE’s ADR define LTD QTY as a unique transport style applicable specifically for air transport. In the UN regulations, only the net quantity of the inner packaging (5kg for UN 3077 and 5L for UN 3082) is fixed. The air rules, ICAO TI, stipulates that the completed package must not exceed 30kg G. Recently, IMDG and ADR followed the 30kg G rule but this provision is not shown on the so-called “blue pages” of the IMDG or the ADR. The “blue pages” only show the maximum permissible net quantity of the inner packaging. The 30kg G rule is only mentioned in the general chapter defining the general conditions of LTD QTY.
Incidentally, UN3334 and UN3335 are not dangerous goods according to IMDG and ADR. For the air mode, if you use LTD QTY, the max for the inner packaging is 5kg or 5L, and the completed package maximum is 30jg G.
Consequently, the 30kg G rule for the air mode had been simply carbon-copied to the IMDG and ADR. There is no special meaning.
Furthermore, in order to eliminate the troublesome re Dec aration process of splitting ID 8000 shipments into each applicable class/division, the letter Y in a diamond Mar ing and PI Y963 were introduced to facilitate intermodal transfers. If without the ID 8000 issue, the Y in a diamond Mar ing May never had come to life.