Architectural Advice Sheet - Operable Walls
Retractable Top Seals
Continuous Contact Top Seals
(At the interface between the operable panel and the ceiling track)
Top Seal - The portion of the operable wall panel that provides the sound and light closure at the panel top between the ceiling track and the operable wall. These Top Seals are typically one of two types: Continuous Contact Top Seals and Manually Operated Retractable Top Seals. By far the most common and most efficient is the Continuous Contact Top Seal, however there are instances where the Manually Operated Top Seal may be desired and instances where it is undesirable.
Continuous Contact Top Seals (also called “top sweep” seals) - These consist of multi-finger-and-loop high grade vinyl seals permanently attached to each horizontal top edge of the panel. These seals remain in constant contact with the surface of the track and provide a sound barrier at the panel top.
Pros of using Continuous Contact Top Seals:
- The laboratory sound tests conducted on operable walls have most often been conducted on panels containing Continuous Contact Top Seals.
- The lifetime maintenance on the operable wall will be significantly less with the Continuous Contact Top Seals.
- Faster setup and storage of the wall with Continuous Contact Top Seals.
- The Continuous Contact Top Seals provide a small degree of friction between the track and the panel which will aid in slowing a panel that has been pushed forcibly along the track (without that friction the free moving panel can be a very dangerous safety concern.)
Cons of using Continuous Contact Top Seals:
- If Hourly Fire Rating are required of the Operable Wall then the Continuous Contact Top Seals cannot be used. In that application the top seal must be retractable and constructed of materials that will resist fire penetration for 1 hour or more. The requirement for Hourly Fire Ratings on operable walls is rare.
- On very tall panels (over 30’ tall) where the panels must negotiate 90 degree intersections, the friction imparted by the Continuous Contact Top Seals will make stacking of the panels more difficult. In those case Continuous Contact Top Seals should be used with a Curve and Diverter track assembly.
Manually Operated Retractable Top Seals (also called “Operable Tops”) - A retractable mechanism incorporating a vinyl sweep seal, similar to the Continuous Contact Top Seal, that is actuated (raised) by the use of a removable handle placed in the edge of each panel. This Operable Top Seal is spring loaded and will extend to contact the underside to the ceiling track.
Pros of using Manually Operated Retractable Top Seals:
- On very tall panels with track intersections of 90 degrees these seals require the least effort to move the operable wall to and from its “in use” position.
- In operable walls requiring Hourly Fire Ratings, Manually Retractable Top Seals are used to enable the partition to pass the 1 Hour Fire Penetration Test. The requirement for Hourly Rated operable partitions is rare.
Cons of using Manually Operated Retractable Top Seals:
- Operable Top Seals can present a very real safety concern since the total lack of friction between the track and the panel will allow a panel that has been set in motion to continue until it either hits someone, something, another panel or a track intersection. None of those occurrences can be good. If panels incorporate Operable Top Seals then the movement of the panels must be very closely supervised by a responsible person. Panels incorporating Operable Top Seals should never be pushed quickly along the track and allowed to move freely. The freewheeling, 500 pound panel can hit with the force of an NFL linebacker.
- Old Technology. Manually Operated Retractable Top Seals are old technology, used back when the carriers for operable walls were not able to negotiate turns easily. Today’s carriers are nearly friction less and the use of Manually Operated Retractable Top Seals is without merit. Because of this, many manufacturers no longer offer Manually Operated Retractable Top Seals. Therefore, competition is limited
- Manually Operated Retractable Top Seals require more maintenance.
- When Manually Operated Retractable Top Seals fail to operate in the retracted position, they will allow significant sound to enter the space defeating the sound rating of the partition.
- The cost of Manually Operated Retractable Top Seals is significantly higher than the cost of Continuous Contact Top Seals.
Summary: For Operable Walls that are designed to be either Individual Multi Directional configurations, Hinged Pair configurations or Curve and Diverter configurations, the use of Continuous Contact Top Seals is highly recommended and the use of Manually Operated Retractable Top Seals is discouraged.
The end user will benefit greatly from the ease of operation and minimal maintenance associated with Continuous Contact Top Seals. The concerns over personal safety and liability associated with the use of Manually Operated Retractable Top Seals cannot be understated.
Manually Operated Retractable Top Seals should only be used with VERY TALL configurations where the panels must negotiate 90 degree turns in order to be placed into and out of the stacking area... and only then when the movement of the panels will be by a trained and conscientious staff.
The only one gaining an advantage with operable top seals is the sales representative who has convinced the architect to specify Manually Operated Retractable Top Seals when they are not really needed.