IFC 4.3.0.1 (IFC4X3) development

# 8.4.3.3 IfcCurrencyRelationship

## 8.4.3.3.1 Semantic definition

IfcCurrencyRelationship defines the rate of exchange that applies between two designated currencies at a particular time and as published by a particular source.

An IfcCurrencyRelationship is used where there may be a need to reference an IfcCostValue in one currency to an IfcCostValue in another currency. It takes account of fact that currency exchange rates may vary by requiring the recording the date and time of the currency exchange rate used and the source that publishes the rate. There may be many sources and there are different strategies for currency conversion (spot rate, forward buying of currency at a fixed rate).

The source for the currency exchange is defined as an instance of IfcLibraryInformation that includes a name and a URL.

## 8.4.3.3.4 Formal representation

ENTITY IfcCurrencyRelationship
SUBTYPE OF (IfcResourceLevelRelationship);
RelatingMonetaryUnit : IfcMonetaryUnit;
RelatedMonetaryUnit : IfcMonetaryUnit;
ExchangeRate : IfcPositiveRatioMeasure;
RateDateTime : OPTIONAL IfcDateTime;
RateSource : OPTIONAL IfcLibraryInformation;
END_ENTITY;