The CASWELL FIRESAFE® system was first developed and tested in the early 2000’s in accordance with British Standard BS476 : Part 24 (1987) at the laboratories of NAMAS / UKAS accredited test facilities for up to 240 minutes Stability, Integrity and Insulation.

Since then, the introduction of harmonised European Standards has involved extensive investment and further testing in order to meet UK and European legislation, including CE marking.

CASWELL FIRESAFE® product has been certified for Smoke Control applications by Applus Laboratories under EN12101:7. The products have been tested to EN1366-1 (2014) and EN1366-8 (2004) classifications, achieving up to 120 minutes. This on-going development has since seen the introduction of a distinctive portfolio of CASWELL FIRESAFE® EN-classified product.

Explaining ‘Stability, Integrity & Insulation’ according to BS476-Part 24

STABILITY – The ability of ductwork – and crucially inclusive of its support system – to remain intact and fulfil its intended function for a specified period of time.

INTEGRITY – The ability of ductwork to remain free from cracks, holes or openings outside the compartment in which the fire is present for a specified period of time.

INSULATION – The ability of ductwork to maintain its separate function without developing temperatures on its external surface, outside the compartment in which the fire is present, which exceed 140°C (284°F) as an average above ambient and / or 180°C (356°F) as a maximum above ambient at any one point.

For Commercial Kitchen Extract ductwork (Duct A) these limitations also apply to the internal surface of the duct within the compartment in which the fire is present. All systems are manufactured to satisfy the requirements of recognised ductwork specifications including DW 144 and DW 172.

Our systems have also been assessed and certified by the following organisations/schemes.
Relevant test criteria, along with assessment and certification data for each organisation, are available on request.

Applus Laboratories, UKAS, BRE, LPCB and UL logos and trademarks

Organisations such as Applus Laboratories, UKAS (United Kingdom Accreditation Service), BRE (Building Research Establishment), LPCB (Loss Prevention Certification Board) and UL® (Underwriters’ Laboratories) are internationally recognised 3rd party experts in the field of Passive Fire Protection and Quality Management. Our accredited systems can be found listed in their web-based certification files.

To maintain these listings, Caswell’s manufacturing facilities are audited by Independent European Certification Limited as part of our ISO 9001:2015  accreditation. This involves stringent checks that the materials produced, the quality regime, traceability, corrective actions and certification are all in accordance with the prescribed specifications and procedures.

An ongoing programme of periodic physical inspections is also conducted in our facility to ensure the required standards are maintained.


If it is your responsibility to manage passive fire protection products, materials or systems – directly or indirectly – then the onus is on you to ensure that they are fit for purpose.

You must ensure that the manufacturer’s fire test and certification evidence fully covers the intended use. It is also your responsibility to ensure that the installer can demonstrate appropriate competency in the installation of the passive fire protection products, materials and systems used.

It is essential that the system is considered ‘as a whole’, including ductwork, fittings, supports, access doors, attenuators, gaskets, sealants, flange clamps and fixings.


Caswell are full members of BESA (Building Engineering Services Association). Caswell Group staff currently hold the role of Chairperson for both the ASFP Ductwork & Dampers Technical Group (TG6) and the BSI (British Standards Institute) FSH 22/-/09 Technical Committee.