British Standard 1710 (BS 1710) provides the standards for identifying pipes, including colour coding, label locations and information about pipe contents. The BS 1710 pipe marking standard is written to be in alignment with the international ISO/R 508 standard "Identification Colours For Pipes Conveying Fluids In Liquid Or Gaseous Conditions In Land Installations And On Board Ships." However, BS 1710 provides for the option of using user defined supplemental colours for 'other liquids' and specifies marking for ventilation ducts and electrical conduits. BS 1710 also specifies the pipe marking for medical gases and refrigerants. This makes the British 1710 pipe marking standard an all-encompassing standard.