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Glossary of Terms

Within the aviation chemical industry, there are a number of terms, phrases and acronyms used to describe the systems, standardised processes or documentation required to meet approval with regulatory bodies or customer requirements.


AS9120 Revision B – this is the quality management standard for distributors of aerospace products, and is an additional qualification to the ISO9001:2015 standard. Please click here to see a copy of Silmid’s AS9120 Certificate.


CAGE Code – CAGE stands for Commercial and Government Entity, and is a coding system that allows the user to identify the exact facility where a product was manufactured. This standardised system is used by defence agencies worldwide. 


CLP Labelling – Classification, Labelling and Packaging of substances and mixtures. This is the regulation used to govern how products are labelled for sale within the European Union. CLP Regulation (EC) 1272/2008 aligns the EU with the GHS system. 

CofA (Certificate of Analysis) – a more advanced document than the CofC, this includes results from specific batch testing carried out after manufacture. 

CofC (Certificate of Conformity) – a document approving the release of a product from a certain company or organisation. 

Commodity Code (sometimes referred to as Tariff Code, Tariff Heading, Schedule B Number or HS Code) – these are 8-10 digit codes used to classify a product for import and export purposes. All products have a commodity code, and this controls the level of taxes and duties paid when shipping product internationally.

Country of Origin – this is the country where the last major stage of manufacture takes place and is required for export/import declarations. 



GHS Labelling – Globally Harmonized System of classification and labelling of chemicals. This is the United Nations method of labelling products to inform users of relevant health and safety information. This has been adopted in the EU via CLP Labelling.


Limited Quantity (often referred to as LQ) – is the maximum inner package size that can ship without hazardous restrictions. This only applies to road freight, and the LQ can be found using the UN number, UN Class and Packing Group found on the SDS.


MRO (Maintenance, Repair and Overhaul) – a term to identify a facility, process or procedure of general upkeep of a piece of equipment. Click here to see more.


NLGI Number (National Lubricating Grease Institute Number). A standardised method for measuring the consistency of a grease. For more information on greases, Click here.


OEM (Original Equipment Manufacturer) – used to describe the initial maker of a product. Click here to see more.


PEO (Piston Engine Oil) – a lubricant used in the operation of piston engines. For more information on PEOs, click here.


REACH – a European regulation to control the sale and use of potentially dangerous chemicals within Great Britain and the European Union. REACH stands for Registration, Evaluation, Authorisation and restriction of Chemicals. Please click here to see a copy of Silmid’s REACH Policy.
RTV (Room Temperature Vulcanizing) – this is used to describe a product (usually a silicone) that cures at room temperature (approx. 15 to 25 °C (59 to 77 °F)).


SDS (Safety Data Sheet) – a legally required document that contains certain product characteristics, allowing the user or transporter of the product to make an adequate risk assessment. 
Specification – a written set of requirements to be satisfied by a material, design, product or service. Click here to read our guide to Specifications.
SVHC (Substance of Very High Concern) – a substance restricted for use and sale within the United Kingdom and European Union. Click here for more information.


TDS (Technical Data Sheet) – this document varies from manufacturer to manufacturer but can include a number of important pieces of information including product characteristics, limitations, usage instructions and more. 
TEO (Turbine Engine Oil) – a lubricant used in the operation of turbine engines. For more information on TEOs, click here.


Viscosity – the thickness of a liquid chemical, usually measured in centistoke (cs or cSt). The higher the centistoke, the thicker the liquid.


UN Number – this is found in Section 14 of the Safety Data Sheet (SDS) and is a 4 digit number used to classify the type of hazard associated with a product. This is determines how the product is transported, in reference to the United Nations standardised Framework.