2.1 When symbolic representation is required for an item not covered in this standard, the character of the symbol shall be adequately identified and shall be subject to one interpretation only. If necessary, a note shall be attached to the symbol for further clarity.

2.2 Symbolic representation does not require exact or scale layouts of the actual system. Therefore, the symbols may be used in all views of the system layout.

1.1 This practice covers symbols used on heating, ventilation, and air conditioning (HVAC) detailed engineering drawings.

1.2 These symbols may be useful on contract and preliminary design drawings.

1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.