Each mechanical engineering office uses their own set of HVAC plan symbols; however, the symbols below are fairly common across many offices.  Refer to the symbol legend sheet for special symbols used in a particular set.

Supply and Return Airflow Symbols

Standard 4-way Diffuser

Standard 4-Way Blow Diffuser

3-Way Diffuser

3-Way Blow Diffuser

2-Way Diffuser

2-Way Blow Diffuser

1-Way Diffuser

1-Way Blow Diffuser

Return Grille

Return Grille

Supply Flow Direction

Direction of Supply Air

Direction of Return Air

Direction of Return Air

Door Undercut

Door Undercut Size

Door Louver

Door Louver with Clear Area

HVAC Damper Symbols

Volume Damper

Volume Damper

Fire Damper

Fire Damper

Smoke Damper

Smoke Damper

Combination Smoke and Fire Damper

Combination Smoke and Fire Damper

Backdraft Damper

Back-draft Damper

HVAC Piping Symbols

Chilled Water Supply

Chilled Water Supply

Chilled Water Return

Chilled Water Return

Hot Water Supply

Hot Water Supply

Hot Water Return

Hot Water Return

Vent Pipe

Vent Pipe

Drain Pipe

Drain Pipe

Make-Up Water

Make-Up Water Pipe

Sensors

Thermostat

Thermostat

Humidity Sensor

Humidity Sensor

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Article Updated: 2019-04-07
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