01 August 2025

Guidance on the presence of self-drilling “tek” screws in legacy fire damper installations

Fire dampers are vital for maintaining fire compartmentation and protecting life and property, and their
correct installation is imperative. In recent years there has been extensive discussion around the use of
self-drilling “tek” screws in fire damper installations, and despite long-standing guidance against their
use, these fixings are still found in many fire damper installations. There are several associated risks:

  • High Melting Point: Tek screws do not melt easily, undermining the function of duct break-away
    joints, which are designed to fail safely under fire conditions.

  • Operational Interference: Tek screws can obstruct damper blades, preventing proper operation
    during a fire.

  • Injury Risk: Sharp edges pose a hazard to maintenance personnel.

It is well-established that for new fire damper installations, tek screws must not be used; however, to
provide enhanced clarity for duty holders of legacy installations, BESA has recently published TB59:
Further Guidance on Ductwork Connections to Fire Dampers.


Where tek screws are found in existing systems, the guidance is as follows:

  • Remove and replace with compliant fixings, where reasonably practicable.

  • If physical constraints prevent removal, the duty holder should arrange for a competent person
    to conduct a risk assessment to determine what additional action should be taken.


Guidance is also provided in relation to the annual inspection & testing of fire dampers, namely:

1. If a damper fails to operate due to the presence of tek screws, it must be reported as a “fail”.

2. If a damper operates, but tek screws are present, it should be reported as “at risk”.

Should you have any queries or wish to discuss how this guidance might affect the fire damper assets
that you maintain, please contact Westbury today.

Tel. 01282 459744

sales@westbury.group



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