Shrink-Out Smoke Vents

Standard Shrink-Out Smoke Vents
Shrink-Out Smoke Vents are gravity operated acrylic double domes designed to automatically shrink and fall out in the event of a fire. These units are generally used when buildings have no sprinkler system or they employ a standard sprinkler system designed to operate at 165 degrees.

ESFR Rated Shrink-Out Smoke Vents
These units are equipped with a fusible link activated release mechanism which will ensure the unit does not activate prior to reaching the fusible link temperature. These units are designed for use with an ESFR (Early Suppression, Fast Response) sprinkler system.

Fusible Link for Controlled Venting:

  • Option for Deck Mount (CSO) and Curb Mount (CSOS) Units
  • Incorporates a 360° or 500° UL Listed Fusible Link for Specific Control of Venting
  • Allows Unit to Be Used with ESFR (Early Suppression Fast Response) Sprinkler Systems
  • UL Tested and Approved
  • Less Expensive Alternative to Mechanical Venting
  • Aluminum retainer frame finish:
    • Mill (Standard)
    • 2605 FEVE Powder Coat, 2605 PVDF, 2604 Powder Coat, and Anodized (more information)
  • Safety screens recommended.
  • Standard Sizes
  • Glazing Options
  • Safety Considerations

Standard Sizes

Model Curb Mount O.D. of Curb Deck Mount* Rough Opening
5555 51″ x 51″ 48″ x 48″
5566 51″ x 63″ 48″ x 60″
5578 51″ x 75″ 48″ x 72″
5596 51″ x 93″ 48″ x 90″
55102 51″ x 99″ 48″ x 96″
6666 63″ x 63″ 60″ x 60″
6678 63″ x 75″ 60″ X 72″
6696 63″ x 93″ 60″ X 90″
66102 63″ x 99″ 60″ X 96″

*Available with 12″ high curbs.

Glazing Options


  • Clear
  • #2412 Bronze


  • Clear
  • #2447 White

Safety Considerations

Skylights pose an inherent risk of injury or death from fall throughs, and the safety of others is of the utmost importance to VELUX.  VELUX recommends that the customer, building owner or manager use additional protection with the skylight such as an exterior or interior safety cage, to enhance long-term safety.  The building owner or manager is responsible for providing fall protection around the skylight in accordance with OSHA regulations.  VELUX also recommends that the building owner or manager restrict roof access only to personnel who have been cautioned as to the location of the skylights, and warned not to sit, step or walk on the skylights.