The fume hood controller communicates with a room controller through group data exchange.

The fume hood setpoint may need to be increased due to laboratory temperature or laboratory airflow requirements. A fume hood demand request will be sent from the laboratory room to maintain proper pressurization.

Variables collected by room:

  • Air flow value for tracking (reflects flow or setpoint)
  • Fume hood minimum provided air flow for exhaust
  • Fume hood maximum provided air flow for exhaust

The fume hood minimum and maximum airflow provided signals are collected by the room.

Variables distributed from room:

  • Occupancy
  • Fume hood exhaust air flow request from room

Exhaust setpoint determination

The exhaust airflow request from the room will only change the exhaust airflow setpoint when the exhaust setpoint selection is set to auto.

When the occupied exhaust airflow setpoint is higher than minimum, the exhaust airflow request from the room will be evaluated against the maximum airflow setpoint.

When the occupied exhaust airflow setpoint is equal to minimum setpoint, the exhaust airflow request from the room will be evaluated against minimum airflow setpoint.

When the unoccupied exhaust airflow setpoint is higher than minimum setpoint, the room exhaust airflow request from the room will be evaluated against the max airflow setpoint. If the exhaust request is higher than the unoccupied exhaust airflow setpoint, the exhaust airflow setpoint will be set equal to the exhaust request.

When the unoccupied exhaust setpoint is less than or equal to minimum setpoint, the exhaust airflow request from the room will be evaluated against the minimum airflow setpoint. If the exhaust request is higher than minimum airflow setpoint and higher than the unoccupied exhaust airflow setpoint, the exhaust airflow setpoint will be set equal to the exhaust request.

Interface

Description

Type

Ref.

Owned by

FhVFace

Fume hood face velocity

AI

●

Room segment / Field device

FhSpAirFlEh

Fume hood exhaust air volume flow setpoint

APrcVal

●

-

FhSpAirFlRelEh

Fume hood exhaust setpoint for relative air volume flow

ACalcVal

●

-

FhVFaceEff

Fume hood effective face velocity

ACalcVal

●

-

FhAirFlReqEh

Fume hood exhaust air volume flow request from room

ACalcVal

●

-

FhAflMinEffEh

Fume hood exhaust effective minimum air volume flow

ACalcVal

●

-

FhAflMaxPvdEh

Fume hood maximum provided air volume flow for exhaust

ACalcVal

●

-

FhAflMinPvdEh

Fume hood minimum provided air volume flow for exhaust

ACalcVal

●

-

FhSpVFace

Fume hood face velocity setpoint

ACalcVal

●

-

FhSpAirFlManEh

Fume hood exhaust manual air volume flow setpoint

ACnfVal

●

-

FhUcdSpVFace

Fume hood unoccupied face velocity setpoint

ACnfVal

●

-

FhOcdSpVFace

Fume hood occupied face velocity setpoint

ACnfVal

●

-