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Application

Model OFSD-311 is an ‘out of the wall’ high performance combination 

fire smoke damper with class I leakage. OFSD-311 is approved for 

use in walls, partitions, and floors with fire resistance ratings less 

than 3 hours. Removal of wall grille allows access to actuator and 

other components. High strength airfoil blades insure the lowest 

resistance to airflow in HVAC systems with velocities to 3000 fpm 

(15.2 m/s) and pressures to 4 in. wg (1 kPa). Model  OFSD-311 shall 

be installed vertically (with blades running horizontal) or horizontally 

and is rated for airflow and leakage in either direction.

Ratings

UL555 Fire Resistance Rating:

 

Fire Rating:

  

1

1

2

 

hours in walls 

 

Dynamic Closure Rating: 

Actual ratings are size dependent 

 

Max. Velocity: 

 

up to 3000 fpm (15.2 m/s) 

 

Max. Pressure: 

 

4 in. wg (1 kPa) - differential pressure 

UL555S Leakage Rating:

 

 

Leakage Class:

 

 

Operational Rating:

 

Actual ratings are size dependent 

 

Max. Velocity:

 

up to 3000 fpm (15.2m/s) 

 

Max. Pressure:

 

4 in. wg (1 kPa) 

 

Max. Temperature:

 

350ºF (177ºC)- depending upon the 

 

 

actuator

Standard Construction

 

Frame:

  

5 in. x 1 in. (127mm x 25mm) 

 

 

galvanized steel hat channel with 

 

 

reinforced corners. A low profile 

 

 

head and sill are used on sizes less 

 

 

than 17 in. (432mm) high. 

 

Blades:

  

Double skin airfoil shape of 

 

 

galvanized steel with full length 

 

 

structural reinforcement. 14 ga. 

 

 

(2mm) equivalent thickness.  

 

Seals:

 

Extruded silicone rubber blade seals.   

 

 

Flexible stainless steel jamb seals. 

 

Linkage:

 

Concealed in jamb 

 

Closure Device:

 

RRL 165°F (74ºC) 

 

Axles:

 

1

2

 in. (13mm) dia. plated steel 

 

Bearings:

 

Bronze sleeve type 

 

Sleeve:

 

Galvanized; wrapped with thermal 

 

 

blanket

Size Limitations:

 

Minimum Size:

  

12 in.W x 12 in. H 

 

 

(305mm x 305mm) 

 

Maximum Size:

  

 

Single section: 

32 in. W x 30 in. H 

 

 

(813mm W x 762mm H) 

 

Multiple Section: 

36 in.W x 36 in. H 

 

 

(914mm x 914mm)

OptiOnAL FeAtuReS:

•  POC retaining Angles
•  RRL/OCI (open closed indication switches)
•  165ºF (74ºC), 212ºF (100ºC), 250ºF (121ºC), 350ºF (177ºC) RRL’s 

available

• TOR (remote override allows damper to perform smoke 

management functions during fire emergency.)

•  Electric or pneumatic actuators to accomplish smoke 

management and system functions.

• Smoke detectors
• Momentary switch
• PRV (pneumatic relief valve)
• Security bars
•Sealed transition and sleeves

Model OFSD-311

Out of Wall Combination Fire Smoke Dampers

Steel Airfoil Blades

UL 555S Leakage Class I

UL555 1

1

2

 Hour Fire Resistance Rating

Horizontal or Vertical Mount

“uL CLASSiFieD (see complete marking on 

product)”

“uL CLASSiFieD to Canadian safety standards 

(see complete marking on product)”

 

Standard 555 & 555S (Listing #R13317)

*  W & H dimensions furnished approximately 

1

4

 in. (6mm) undersize. 

(Add blanket thickness (

1

8

 in.[3mm]) and sleeve thickness for 

overall sleeved damper dimension) 

Oversize wall opening as follows: 

Nominal damper size plus 

3

8

 in.(9.5mm) (

see page 6

)

R

Greenheck Fan Corporation certifies that the 
model OFSD-311 shown herein is licensed to 

bear the AMCA Seal. The ratings shown are 

based on tests and procedures performed in 
accordance with AMCA Publication 511 and 
comply with the requirements of the AMCA 

Certified Ratings Programs. The AMCA Certified 

Ratings Seal applies to air performance ratings 
only.

Model OFSD-311 meets the requirements for fire 

dampers, smoke dampers and combination fire 

smoke dampers established by:

national Fire protection Association 

    NFPA Standards 80, 90A, 92A, 92B, 101 & 105

iBC international Building Codes
iCBO  uniform Building Codes  
SBCCi  Standard Building Codes
CSFM California State Fire Marshal 

  Fire Damper Listing (#3225-0981:103)
  Leakage (Smoke) Damper Listing (#3230-0981:104)

new York City 

(MEA listing #260-91-M)

installation instructions available at www.greenheck.com

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