Transom Spring Unit

What is a Transom Spring Unit?

Transom spring units are hydraulic units fitted in the door frame to aid door closing on more industrial and commercial use doors. Not all locations are suitable for floor spring units due to under floor pipework, flooring materials and the depth of floor available, in this occasion a transom spring unit would be most suitable option.

Transom spring units are more commonly found on shop fronts, as they are predominantly fitted within a purpose made section of an aluminium or steel frame. Transom springs can be fitted into a timber purpose made frame but the size will need to be taken into consideration.


Which Transom Spring unit should I buy?

Listed below are the main factors that have to be taken into consideration when purchasing a transom spring unit:

  • Door weight and width
  • Traffic flow
  • Door location
  • Fire doors
  • Special requirements
  • Cost
  • Additional door parts


Door Weight and Width

There are various transom spring units available. All manufacturers will have a maximum door width and weight for each of their products. This is usually determined by the different strengths of the models.


Traffic Flow

A door which gets a lot of use i.e. Main Entrance Door to a Restaurant, may require a more heavy transom unit than an internal office door.


Door Location

There are 3 main locations which will have specific needs.

  • Internal Doors - Some internal doors have specific needs i.e. are required to swing both ways (double action) as in kitchen doors.
  • External Doors - These may need to be closed for security, with the option of being held open i.e. when deliveries are being bought into the building


Special Requirements

Some locations have specific needs. You may require a transom spring unit with back check facility to buffer the door hitting the wall behind it. A location may require the door to latch onto a security lock or magnet, therefore a transom spring unit with adjustable latching action would be required to set the door correctly.



The cost can vary enormously between the strength of units and manufacturers.

As a general rule as long as the above considerations are taken into account you should get a suitable product for your location.


Additional Door Parts

To fit a transom spring unit to a door, you will require additional parts fitted to the door and at the bottom of the frame. These parts include various different drive arm assemblies and bottom bearing assemblies. Please note there are many different types of these parts dependant on the make of unit, existing door parts and type of door.

DDA Regulations

The Disability Discrimination Act regulations came into force in October 2004. You must ensure your doors cover the necessary requirements for your location when you fit any form of door closing equipment to your door.


Return to main products page