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Surface Mounted Drop Down Smoke Seal

End view of the astro dbsm surface mount drop down seal showing the metal and black plastic components
4.8 out of 5 stars

2 In Stock

For dispatch today order within
11 Hrs 56 Mins

£51.05 inc VAT

£42.54 ex VAT

Next Day Delivery

Will usually be delivered the next working day

£7.00 inc VAT

Fire doors with a gap of 5mm or more at the bottom require a threshold seal to maintain integrity. The surface mounted drop down smoke seals offer a quick and easy solution to preventing smoke, draughts and even sound from passing through the gap at the bottom of a fire door. Suitable for gaps of up to 14mm, these seals are ideal for retrofitting as they require no routing or rebating. When the door is closed a plunger makes contact with the door frame and lowers the PVC rubber pad in the bottom of the unit, effectively sealing the gap under the door.

  • Surface mounted drop down threshold seal
  • Suitable for push or pull side installation
  • Graduated scissor action – seal drops on hinge side before lock side
  • Available in a range of lengths: 330 - 1030mm
  • Lightweight satin anodised aluminium construction
  • Insulates against smoke, draughts and even sound
  • Ideal for retrofitting existing fire doors
  • Suitable for use with surface mounted fire door seals
  • Easily trimmed to fit any door (maximum trimming length 150mm)
  • Supplied complete with fixing screws
  • Maximum drop: 14mm

Please Note: This seal operates via a graduated scissor action, meaning that the seal drops on the hinge side before the lock side. Once installed correctly the entire length of the seal will drop when the door is fully closed.

Customer Reviews

Customer Reviews (6)

4.8 out of 5 stars

Reviews by Real Customers

All of our product reviews are written by real customers that have purchased this product from us and are published without modification.

Rating: 5 / 5

Reviewed by

J G

Published on

7th October 2025

Great after sales support

Applies to option(s): 330mm

Rating: 5 / 5

Reviewed by

R R

Published on

27th June 2025

Great quality, our go to for drop down seals

Applies to option(s): 330mm

Rating: 4 / 5

Reviewed by

T O

Published on

25th April 2024

would like certified installation of products as part of the service

this way customer gets the product installed properly so it does what it is intended to do.

And you get more business because there might be other things that need to be done aswell.

Applies to option(s): 330mm

Rating: 5 / 5

Reviewed by

S T

Published on

1st February 2022

Perfectly designed product

Applies to option(s): 330mm

Rating: 5 / 5

Reviewed by

S T

Published on

1st February 2022

Perfectly designed product

Applies to option(s): 330mm

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Technical Data

Technical Data

Product Code AFASDBSM/430
Brand Astroflame
Colour Silver
Compliance BS EN 1634-3
Door Type Wooden Doors
Fixing Options Screws (included)
Surface Mounted
Installation Position Bottom Of Door
Insulating Properties Acoustic
Material Aluminium
Rubber
Recyclable Not Recyclable
Suitability Single Doors
Dimensions (Unit)
  • Height: 40mm
  • Width: 430mm
  • Depth: 13mm
Weight 210g
Datasheets