The International Organization for Standardization (ISO) is a network of national standards bodies that represents the world’s largest developer of voluntary International Standards. The British Standards Institution (BSI) is the UK’s National Standards Body and is responsible for producing and publishing British Standards and for representing UK interests in international and European standards organsations such as ISO. ISO documents are developed as international standards and documented as “ISO [Standard Number]”. Once ISO documents are published, they can be republished by individual countries as a national adoption. For example, when the EU adopt an ISO Standard, the letters “EN” are added to the document name, e.g. “EN ISO [Standard Number]”. Following adoption, the documents may be produced officially in different languages (e.g. English by the BSI), which adds an extra part to the document name, such as “BS EN ISO [Standard Number]” in the UK, or “DIN EN ISO [Standard Number]” in Germany, for instance. There are several ISO Standards for Assessing Thermal Environments.