Product Standards - Flameshield Fireduct is Fully Compliant with BS 476 Part 24
Flameshield Products have been fully tested in accordance with BS 476 Part 24: 1987 (ISO 6944: 1985)
for up to 2 hours stability, integrity and 2 hours insulation for Type A ducts (fire outside)
and 4 hours stability, integrity and 2 hours insulation for Type B ducts (fire inside).
The standard for assessment involves a variety of different scenarios to ensure the ductwork
meets all current requirements. Flameshield Fireduct also meets the smoke extract
criteria of up to 4 hours integrity.
Flameshield Fireduct, exceeds all the minimum requirements for fire resistance in ductwork,
making it the first choice to stay compliant.
The test duct details are much the same for both of these standards (BS 476 Part 24 and
EN 1366 Parts 1 & 8) however the requirements set down within the
two standards are different in many ways.
BS 476 Part 24
It is a requirement to test two different scenarios, duct A (fire exposure from outside
to inside) and duct B (fire exposure from inside to outside). A BS 476 Part 24 test is
required for both duct A and duct B standards, insulated and un-insulated and rectangular
in shape, all installed horizontally. Under the requirements specified within this test
standard other orientations can be assessed. For example:
- The test standard enables ducts sized up to 1250x1000 (rectangular), or 1000 diameter (circular) to
be incorporated as part of a tested solution. Ducts sized over these maximum tested solutions can
Following a successful duct B test the cross sectional area of the duct can be measured
to determine the ‘loss of shape’ after being exposed to the furnace gasses. The standard
requires the duct to maintain at least 75% of its original shape.