Skolnik

When a container is certified to a specific UN criteria, this represents the upper limit of the specifications to which the container must be manufactured. The UN does allow for a smaller capacity container to qualify under the same UN Certification. CFR 178.601(3)Variation 3 states that ‘other than combination packagings, reduction of external dimensions (length, width or diameter) of up to 25% of the dimensions of a tested packaging may be used without further testing provided an equivalent level of performance is maintained.’ Furthermore, metal wall thickness must be identical to the design type, and the marked gross mass must be reduced in proportion to the reduction in volume.

We recently had a customer request the manufacture of a UN Certified container with a "36 inch inside height." The order was received without a detailed illustration indicating where and how the measurement was to be taken. In order to indicate the necessity of specification drawings, we asked the entire SKOLNIK staff to illustrate where they would measure this dimension. Some asked "is the cover on or off? Some asked "do we measure at the perimeter or the center?" And so went the exercise until there were five groups of measurement types. Finally, we provided the customer with an illustration and asked for their dimensional location, and to our surprise, it was different from any of those indicated by the staff! Therefore, this exercise clearly indicates that specification drawings must be provided when specifying a dimensional change in the container. If a customer is not able to produce such a drawing, the SKOLNIK engineering staff will be pleased to provide these documents as a part of the ordering process. IF YOU ARE CURIOUS — the intended measurement was at the inside center of the drum with the cover on!