Basics of Legal for Trade Approvals/Certifications
by Carl S. Joslyn and Philippe Humbert
Scales are used for selling products by weight, and are
commonly governed by legal standards. Often called "approved"
or "certified" scales, these legal-for-trade scales have to meet
different standards in Europe, the US and Canada. This article
generally covers the topic of legal for trade requirements in each
area.
Legal for Trade (often also called "Approved") applications are
legally-required and commonly occur where products are sold
directly to the public based on weight and sometimes count.
The most easily understood of these applications is retail price
computing, where a container of food is sold to a consumer using
the net weight of the food multiplied by a price per lb or
kg. Most consumers will come across this in supermarkets,
delis, meat shops and farmer's markets, and the scale involved may
stand-alone on a counter or may be integrated into a checkout
scanner. In all instances, the scale model has to be tested
and certified/approved by a testing lab and then the actual sale
used is calibrated, tested and sealed by a government agency.
Some common legal for trade applications are:
o Retail sale of products directly to the
public
o Packaging items for sale by weight in a
store
The general international standard is OIML, which like NTEP
establishes the standards and approval of equipment for
weighing. Each participating country may then implement OIML
slightly differently, but on the whole the OIML standard provides a
global basis for approving scales.
NTEP evaluates scales and other equipment
against the applicable standards
In the US, the governing standard is often called "NTEP", Handbook
44. Each of these terms refers to a program of cooperation
between the National Conference on Weights and Measures (NWCM), the
National Institute of Standards and Technology (NIST) and each
state's weights and measures system. Through twelve
participating laboratories, NTEP evaluates scales and other
equipment against the applicable standards. Once a product
has received NTEP certification, it can then be accepted readily by
the local weights and measures agency for use in the sale of
products to the public, or in other situations where NTEP
certification is required. While OIML, EC-type approval and
NTEP may have many similarities, in the US the NTEP is the measure
of a product's certification.
In Canada, approval is governed by standards and testing by
Industry Canada under the Measurement Canada approval
process. Just as OIML and EC-type approval does not translate
into acceptance in the US, Measurement Canada approval is required
even if the product is NTEP certified.