BackdraftDampers

Backdraft Damper Training

ApplicationBackdraft dampers allow air to flow in one direction only and prevent unwanted (hot/cold outside air, wind, etc.) from“back-drafting” into the building.

They only install in ducts, at walls, or in roofs and open automatically when air flows in the intended direction and automatically close when there is no air pressure or when airflow is in the opposite direction.

Basic Functions

• Intake/Exhaust • Barometric/Pressure Relief

Backdraft Damper Training

Intake

Intake backdraft dampers allow supply airflow into a building while preventing conditioned air from escaping when the fan is off.

Typical Applications• Intake Air Duct - Wall or plenum mounted• Intake side of rooftop evaporative cooler (requires counterbalance)

Backdraft Damper Training

ExhaustExhaust backdraft dampers allow air to automatically exit the

building and prevent outside air from entering the building.

Typical Applications

• In tandem with wall mounted exhaust fan.• Exhaust air duct - wall or plenum mounted• Roof top power ventilator • Rooftop gravity ventilator

Wall Mounted Exhaust Fan

Backdraft Damper

Backdraft Damper

Roof Top Power Ventilator

Backdraft Damper Training

BarometricBarometric relief dampers open automatically under low velocity

conditions - including natural airflow - and close automatically to

prevent reverse airflow.

Typical Applications

• Rooftop gravity ventilator• Wall mounted relief (no duct or fan)

Backdraft Damper

Roof Top Gravity Ventilator

Backdraft Damper Training

Pressure ReliefPressure relief dampers use counterbalance weights to maintain a relatively constant upstream pressure, they open automatically at higher pressures and close automatically when pressures drop.

Typical Applications

• Duct or plenum relief

• Room relief

Backdraft Damper Training

AMCA 500D Test Requirements

Test Samples• Pressure drop: 12x12, 12x48, 48x12, 24x24, 36x36

Pressure Drop• Ducted Inlet and Outlet - AMCA 5.3 Lowest Pressure Drop• Ducted Inlet Only - AMCA 5.2• Plenum Mount - AMCA 5.5 (Highest Pressure Drop) AMCA 5.3 – Ducted Inlet & Outlet

AMCA 5.2Ducted Inlet

AMCA 5.5 – Plenum Mount

Backdraft Damper Training

Design Basics and Typical Application

Light Duty• Most common type and widely used for intake, exhaust, barometric, and pressure relief applications where air pressures and velocities are low (≤ 2 in wg. & 1250 fpm).Medium Duty• Typically used for intake, exhaust, and pressure relief when pressure or velocity exceeds the light duty range (>2 in wg. & 1250 fpm, but ≤3 in. wg. And 2500 fpm.Industrial• Employed when the temperature, pressure, or velocity exceed standard commercial damper limits. Units are typically flange mounted directly to the duct or fan housing.

Backdraft Damper Training

Light Duty Backdraft DampersApplications

– BD-50• Gravity Intake and Exhaust • Prop-Fan Exhaust • Roof Top Power Ventilator

– BD-51• Intake or Exhaust – where damper blade noise is a concern

– BD-52• Evaporative Cooler – Discharge Side (down-flow only)

– BD-54• Pressure Relief

Mounting Arrangements– Vertical Mount – Horizontal Mount

• Up-flow• Down-flow (BD-52 Only)

Caution– Multiple Sections– Maximum Velocity & Pressure Limits– No Exact Pressure Settings

Vertical Mount Horizontal Mount

Adjustable Counterbalance

Weight

Tie-Bar

Integral Counterbalance

Weight

Channel Frame

Backdraft Damper Training

Medium Duty Backdraft DampersApplications

– BD-60• Fan Exhaust - Duct or Plenum Mount

– BD-64• Pressure Relief - Higher velocity

Mounting Arrangements– Vertical Mount – Horizontal Mount

• Up-flow only

Caution– Low-end velocity and pressure limits– No Exact Pressure Settings – Retarding Counterbalance Design Only - No assist to Open

Vertical Mount Horizontal Mount

Hat-Channel Frame

Concealed Linkage

Adjustable Counterbalance

Weight

Backdraft Damper Training

Industrial Backdraft Dampers

Applications– BD-84

• Fan Exhaust - duct or plenum mount

Mounting Arrangements– Vertical Mount only

Caution– Low-end velocity and pressure limits– No Exact Pressure Settings – Assist to Open Counterbalance

design only

Channel Frame

Concealed Linkage

Adjustable Counterbalance

Weight

Backdraft Damper Training

Options & Accessories

Flange Frame• For flush mounting to equipment/wall• Intake or discharge

Sleeve

304 Stainless Steel Construction

Electric Actuator (BD-58 Only)

Backdraft Damper Training

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