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A Guide to Trade Approvals: What is a Trade Approved Scale?

Weighing scales are used throughout countless different types of industry, for many different applications. For some of those applications, though, a standard weighing scale is not suitable and trade approved scales must be used. 

But what are trade approved scales, and why should you be using them? In this blog post, we explain the importance of using a trade approved scale, the applications in which such a scale must be used, and how you can tell if the scale you're using is trade certified. 

  • What is a trade approved scale?
  • Do I need a trade approved scale?
  • What is the law on using trade approved scales?
  • Who can certify a trade approved scale?
  • How do you know if your scale is trade approved?
  • Different classes of trade approved scale

What is a trade approved scale? 

A trade approved weighing scale is the name given to any weighing scale that is legally allowed to be used to weigh subjects that are priced by their weights. These scales have undergone rigorous testing to ensure that they are built and tested to a specific standard. Trade approved scales are therefore more accurate and ultimately provide protection to a buyer as they will be receiving the correct amounts of whatever they purchase. As an example, a regular kitchen scale for home use would not need to be trade approved, but a scale found in a sweet shop would. The main industries that may require trade approvals are industrial and commercial scales, jewellery scales, professional food scales and retail scales.     

Do I need a trade approved scale? 

In the UK, it is the law that you must use a trade approved scale for selling items with a price that is directly related to its weight. This is the case for any industry and no one is exempted. If you own a store such as sweet shop, fruit and veg shop or weigh shop, you will require retail scales which are commonly trade approved.  

Other than a shops, here are the most common products that require the use of a trade approved scale: 

  • Food stuffs (legal for trade food scales) 
  • Soaps 
  • Meat and fish (legal for trade butchers scales) 
  • Bottle goods such as alcohol 
  • Fuels 
  • Precious metals and jewels (legal for trade jewellery scales) 
  • Animal feeds  
  • Packed products that specify weight 

For a detailed break down of trade approvals, the Non-automatic Weighing Instruments (NAWI) Directive 2014/31/EU states that trade approved scales must be used in the following circumstances: 

  • Determination of mass for commercial transactions  
  • Determination of mass for the calculation of a toll, tariff, tax, bonus, penalty, remuneration, indemnity or similar type of payment  
  • Determination of mass for the application of laws or regulations; expert opinion given in court proceedings 
  • Determination of price on the basis of mass for the purposes of direct sales to the public and the making-up of pre-packages. 
  • Determination of mass in the practice of medicine for weighing patients for the purposes of monitoring, diagnosis and medical treatment. 
  • Determination of mass for making up medicines on prescription in a pharmacy and determination of mass in analyses carried out in medical and pharmaceutical laboratories. 

A common misconception of trade approved scales is that they are required for mixing ingredients to make a product, such as soaps, candles or food items. This is not the case and a trade certified scale would only be necessary at the end of the process if these items were being sold by weight – ‘100g of soap’ for example.  

What is the law on using trade approved scales? 

As previously mentioned, it is the UK law that trade approved scales must be used for selling subjects based on weight in accordance with the ‘Weights and Measures Act 1985’. 

Officers from Trading Standards have the right to visit a business at any time to check that weighing equipment meets the guidelines and is legally fit for trade. 

Anyone found not using trade approved weighing scales can receive a 28 day notice, face fines of over £1000, or in worse case scenarios, a prison sentence. It’s important to remember that it’s also illegal to tamper with trade approved scales after they have received their approval, or to use weighing scales that are severely inaccurate.  

Who can certify a trade approved scale? 

Trade approval certification may only be given by a known Weights and Measures inspector or an approved qualifier. The assessment process includes the checking of the scale’s overall design and usability, with scrupulous guidelines on accuracy and outside interference having to be adhered to for it to be verified as legal-for-trade. If the weighing scale passes, it is given a Declaration of Conformity as physical proof that the instrument has been tested and is fit for trading purposes.   

How do you know if your scale is trade approved? 

You can tell if your weighing scale is trade certified in a couple of ways: 

The first, and perhaps most obvious, is to check the website, packaging or order details of your weighing scale. Bear in mind that your scale may not be labelled as trade approved, but may be referred to as being Class III approved scales, legal for trade scales, verified, EC stamped or stamped scales. If you’ve purchased a weighing scale from Inscale and you’re not sure if it’s trade approved, please contact us.

SWZ Dataplate  

The second way to tell if your scale is trade approved is to check the markings on the dataplate, located on the underside of your instrument. Typically in the UK, you will find a CE (European Conformity), and an M or Class II/Class III mark to signify that you scale is trade approved. The M symbol is now black, but has been green in the past, and some older scales may also have a crown stamp. On the image above we can see the CE symbol, as well as the M21 mark which indicates when the scale recieved its trade certification. 

Different classes of trade approved scale 

The accuracy of a trade approved scale can be defined by which class it sits, with each class being fit for different purposes. It’s important to use a scale with the correct class for your intended use – if not, you may be breaking the law. Let’s take a look in more depth:  

  • Class 1 & 2 trade approval – Scales with this level would be used for high accuracy weighing, such as weighing gold, precious stones and pharmaceutical purposes.  
  • Class 3 trade approval – This is the most commonly found type of trade approval and is for general weighing purposes, such as retail scales and most industrial and commercial scales. For scales with readabilities of 0.1g to 2g. 

 If you are still unsure of what class is right for you, it’s best to either Get In Touch with us or Trading Standards directly. 

See our full range of trade approved weighing scales here

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