Laboratory Ventilation For Health

1
Fume Hood Airflow Control Via Siemens Venturi Air
Valve
Control Process
1. Controller Determines Sash Position
VAV Fume Hood Controller
Siemens Venturi Air Valve
2. Controller Calculates Total Open Area
Sash Height x Width
400 cfm
Fixed Open Area
Airflow Sensor
3. Controller Calculates Reqd. Exhaust
Area Ft2 x Face Velocity
(4 Ft2 x 100 Ft/Min 400 Ft3/Min (400 CFM)
4. Measure Airflow Compare
5. Position Cone
Sash Sensor
2
Siemens Venturi Air Valve
Electric Actuator
Orifice Plate Airflow Sensor
Airflow Measurement Makes SIEMENS Unique !
dP Taps For Airflow Measurement
3
Laboratory Ventilation Air Consumption vs.
Type of Hood
Constant Volume Bypass
FULL EXHAUST AT ALL TIMES

• AIRFLOW RELATIVELY
• CONSTANT AT ALL TIMES

CAV bypass hood exhaust to remain essentially
unchanged (less than 5 change).Z9.5
VERY COSTLY TO OPERATE
6 FUME HOOD _at_ 1250 CFM ANNUAL COST.3750 to
6250
Annual average cost of 3 to 5 per CFM
100 OPEN
50 OPEN
FULLY CLOSED
4
Laboratory Ventilation Air Consumption vs.
Type of Hood
Constant Volume Bypass - 2 Position
EXHAUST REDUCTION DURING UNOCCUPANCY
UNOCCUPANCY
ROOM CONTROLLER
SASH CLOSED

• SAME AS REGULAR CAV
• DURING OCCUPANCY.

• AIRFLOW REDUCED TO 20
• DURING UNOCCUPANCY.

• WORKS IN CONJUNCTION NNWITH
  SUPPLY AIR REDUCTION.

100 OPEN
50 OPEN
FULLY CLOSED
5
Fume Hood Shutdown Requirements
1. Maintain Required Room Ventilation Rate
(ACH).
2. Maintain Room Negative Pressurization if
..Hazardous Substances Are Present in
Room.
3. Remove All Chemicals From Fume Hood.
W a r n i n g Fume Hood is Not
Operational. Do Not Use !
4. Post Sign
W a r n i n g Fume Hood is Not Operational. Do
Not Use !
6
CAV 2 - Position Laboratory Ventilation Control
EXHAUSTAIRFLOW
SUPPLY AIRFLOW
CAV 2 - POSITION CONTROLLER
ROOM CONTROLLER
INFLOW FROM ADJACENT AREAS
Laboratory Room
CAV FUME HOOD
7
Laboratory Ventilation Air Consumption vs.
Type of Hood
Variable Air Volume
EXHAUST MODULATION FOR CONSTANT FACE VELOCITY
VAV FUME HOOD FACE VELOCITY CONTROL BY SASH
SENSING
RESTRICTED BYPASS
SASH
SASH POSITION

• AIRFLOW CONTROLLED TO ENSURE
• CONSTANT FACE VELOCITY.

• AIRFLOW REDUCED TO 20 WHEN
• SASH IS FULLY CLOSED.

• COST OF OPERATION TYPICALLY
• 40 OF CAV BYPASS FUME HOOD

100 OPEN
50 OPEN
FULLY CLOSED

• ALSO REQUIRES VAV ROOM
• VENTILATION CONTROL.

8
VAV Laboratory Ventilation Control
EXHAUST AIRFLOW
SUPPLY AIRFLOW
VAV FUME HOOD CONTROLLERS
EXHAUST
Laboratory Room
INFLOW FROM ADJACENT AREAS
VAV FUME HOODS
9
Laboratory Room Ventilation
Negative Room Pressurization
Inward Airflow

Airflow Tracking
? Airflow Tracking
SUPPLY
EXHAUST
10
System 600 APOGEE
Dynamic Graphics
FUME HOOD 046
SASH HEIGHT 0 Inches
SASH HEIGHT 18 Inches
SASH HEIGHT 28 Inches
EXHAUST 525 CFM
EXHAUST 250 CFM
EXHAUST 800 CFM
FACE VELOCITY NORMAL
FACE VELOCITY 103 Ft./Min.
FACE VELOCITY 64 Ft./Min.
11
Integration

• Siemens can utilize existing Phoenix Air Valves
  with existing electric actuators or with a
  Siemens electric actuator.
• Siemens would add airflow measurement to enhance
  performance.
• Siemens laboratory controls can be integrated
  into the existing Automated Logic system
  utilizing Bacnet.