HVAC Abbreviations List: 264 Terms in a Free DWG Legend

A ready-made HVAC abbreviations legend for drawings, with 264 terms grouped by equipment, fans, air distribution, dampers, piping, valves, controls, design parameters and units.

About

What is in this legend

This HVAC abbreviations legend puts 264 terms into one table you can paste straight onto a drawing sheet. The list is split into thirteen groups, so a reader can find a term without scanning the whole sheet: equipment, fans, pumps and hydronic equipment, air streams, air distribution, dampers, AHU components, piping services, valves and pipe accessories, controls and BMS, design parameters, units, and levels and general terms.

The table is drawn at paper size in millimetres, 510 mm wide and about 380 mm tall, laid out in four columns. That fits beside the title block on an A1 sheet at a scale of 1 in paper space. All text is single line text on its own layers, not locked inside a block, so you can edit, delete or add rows directly.

Terms you will meet on Gulf projects

Most lists online are written for North American work and miss terms that turn up on every drawing set in Saudi Arabia and the Gulf. This one includes them. TFA, the treated fresh air unit, and PAU, the primary air unit, both describe a unit that conditions outdoor air before it reaches the space, and you will see both names used for very similar equipment depending on who the consultant is. A sand trap louvre is a louvre with deep blades that drop out wind-blown sand before it reaches a fresh air intake, and it is a standard item on fresh air and generator room intakes in the region. An ecology unit sits on kitchen exhaust to take out grease, smoke and odour before the air leaves the building.

On the hydronic side, the list covers both DRV, the double regulating valve used on British-style specifications, and CBV, the circuit balancing valve used on American ones. They do the same job on a chilled water circuit. Which one appears on your drawings depends on the specification, not on the engineer’s preference, so check the spec before you settle on one.

Abbreviations with more than one meaning

A few HVAC abbreviations mean different things to different people, and a legend that lists both meanings defeats the point. In this table each abbreviation has one meaning only. CU is the condensing unit, so copper is written in full. HP is horsepower, and heat pumps are listed as ASHP and WSHP. BF is the bag filter in an air handling unit. CD is the condensate drain. DN is the nominal diameter of a pipe. Normally open and normally closed are written as N/O and N/C, so they do not get mixed up with NC, the noise criteria rating.

If your consultant uses a different convention, change the legend to match theirs rather than the other way round. A consultant who reads FD as a filter drier and finds fire dampers marked FD on your drawings will not be pleased.

Using HVAC abbreviations on a drawing set

Put the full legend on the first sheet of the HVAC set or on a dedicated legend sheet, and refer to it from the other sheets. Repeating the full table on every drawing wastes space and makes revisions harder, because every copy has to be updated when a term changes.

Trim the list to the project before you issue. A residential building with split units does not need CRAH, CRAC and TES on its legend, and a short list that matches what is on the drawings is easier to check. Keep the full version in your template and cut it down per job.

The same abbreviations should run through everything that comes out of the design: equipment schedules, the BMS points list, the bill of quantities and the testing and commissioning sheets. When the drawing says FAHU, the schedule says AHU and the BMS list says TFA for the same unit, the commissioning engineer is left guessing which is which. Fix the names on the legend first and use them everywhere else.