Flameshield Fireduct - Technical Features
Fire resistant ductwork needs to meet a wide range of criteria to be standards compliant, and
depending on the application, involves testing for fire exposure from both the outside (Type A)
the inside (Type B) and smoke extraction Type C).
Flameshield Fireduct has been fully tested to meet Types A and B criteria for BS 476-24 and
ISO 6944 and has now fully achieved Types A, B and C criteria for BS EN 1366-1 parts 1 & 8.
This means all required testing has been undertaken and will be able to be CE marked when the
appropriate product standards have been published. You can be fully confident when specifying
Flameshield Fireduct for ventilation and extraction systems and even for critical means of
escape systems. It is listed for all standards in the Red Book Live.
Flameshield Fireduct meets all of these requirements and more.
BS 476 Part 24 test standard compliancy
Flameshield Fireduct meets the standard for Type A where ductwork should demonstrate 2 hours
of fire resistance.
Flameshield Fireduct meets the standard for Type B where ductwork should demonstrate 4 hours
of fire resistance.
Flameshield Fireduct also meets the smoke extract criteria of up to 4 hours integrity.
Stability and integrity ratings are used to analyse test outcomes. Stability is measured by the
ability of a smoke extract duct to retain at least 75% of its cross sectional area along its
whole length, both inside and outside of the furnace, and failure occurs when the duct
collapses and no longer fulfils its function. The presence and the formation of cracks,
holes or other openings outside the furnace through which flames or hot gases can pass shall
constitute integrity failure.
In different application areas, different accessories are required for the optimum operation of
the system. For example, some areas may require dampers to ensure integrity and other areas such
as kitchen extract systems should not have fire dampers incorporated as the extremely high
temperatures within the duct and accumulation of grease may prevent the damper from closing,
deeming it ineffective.
Insulation failure is considered when the temperature rise above initial ambient
temperature, on the unexposed surface of the test specimen outside the furnace, exceeds either:
140 C plus ambient as an average value,
or;
180 C plus ambient as a maximum value.
Flameshield fireduct is guaranteed to maintain integrity and stability in each case.