Basics of Legal for Trade Approvals/Certifications
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 or even integrated into a network. In all instances,
the scale model has to be tested and certified/approved by a
testing lab and then the actual scale used is calibrated, tested
and sealed by a government agency.
Some common legal for trade applications are:
- Retail sale of products directly to the public
- Packaging items for sale by weight in a store
- Truck weigh stations on highways
- Recycling and waste disposal operations
- Grain testing
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.
In the European Union, the Council Directive 90/384/EEC of 20
June 1990 on the harmonization of the laws of the Member States
relating to non-automatic weighing instruments (NAWI) is the base
for EC Type Approval. Every EU country has its own Weighing and
Measurement Legal Authority, and all of them are able to deliver an
EC Type Approval. EC Type Approval is demonstrated by meeting the
requirements of BS EN 45501 which is equivalent to OIML R76.
In the US, the governing standard is often called "NTEP",
"Handbook 44" or "HB44". 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.
OIML
For more information, please go to http://www.oiml.org/
NTEP
For more information, please go to http://www.ncwm.net/ntep/
Measurement Canada
For more information, please go to
https://strategis.ic.gc.ca/eic/site/mc-mc.nsf/eng/Home