BS 476 Part 6 measures the fire propagation index of a material: how much heat it releases into a controlled flue as it burns, compared against calibration boards. The index and sub-indices from this test feed the UK building regulations system for wall and ceiling linings, where Class 0 is built from Part 6 and Part 7 results together. The Motis fire propagation apparatus is built for this method.
How the Fire Propagation Apparatus (BS 476-6) works
A small flat specimen forms one wall of a combustion chamber fitted with gas burners and an electric element. Thermocouples in the chimney record the temperature rise of the exhaust gases over the 20-minute test. The temperature curve is compared with the curves from calcium silicate calibration boards to calculate the fire propagation index and its sub-indices for the first three minutes, the following minutes and the full test.
Key specifications
| Standard | BS 476 Part 6 - fire propagation test for materials |
|---|---|
| Output basis | Exhaust-gas temperature rise compared against calibration board curves |
| Related configuration | ISO 5658-2 spread of flame configuration is covered in our flame spread range; see the flame spread radiant panel page |
What the test reports
- Fire propagation index (I)
- Sub-indices i1, i2 and i3
- Exhaust temperature curve over the 20-minute test
Applications
Building material manufacturers selling into the UK and Commonwealth markets use Part 6 data for lining classifications, and laboratories run it alongside the Part 7 surface spread of flame test, which we also supply.
Frequently asked questions
Which standard should I order against?
Order against the standard your reports must cite. The instrument platform is shared across the listed standards, but fixtures, software templates and calibration routines differ, so name the standard (and its year) in your inquiry and the configuration will be matched to it.
Can the instrument be installed in an existing laboratory?
Yes, in most cases. Tell us the available floor space, ceiling height, exhaust capacity and gas supplies in your inquiry; large systems such as the SBI and tunnel furnaces need a dedicated exhaust arrangement, which is confirmed in the layout proposal before ordering.
What specimen size does Part 6 use?
The method works on small flat specimens that form the chamber wall; the exact dimensions and conditioning are defined in BS 476 Part 6 itself. Confirm specimen preparation against the current edition of the standard when you set up the test.
Configuration, installation and support
Every Fire Propagation Apparatus (BS 476-6) is supplied as a configured system, not a bare instrument: the test chamber or frame, the burner or heater assemblies named in the method, the measurement chain and the control software with the report templates for BS 476 Part 6, ISO 5658-2 family. Before quotation we confirm the installation conditions with you - floor loading and ceiling height for large rigs, exhaust and extraction routes, gas and fuel services, and power supply - because a fire test instrument only produces defensible data when the room around it is right. Commissioning covers assembly, calibration of the measurement chain against the method's own checks, and training of your operators on running the test and maintaining the apparatus. Spare ignition parts, thermocouples and other consumables for the first period of operation can be included in the supply, and the instrument is supported with calibration and maintenance services after installation.
What to include in your inquiry
To quote the Fire Propagation Apparatus (BS 476-6) correctly the first time, send: the standard and edition you will test to (BS 476 Part 6, ISO 5658-2 family); the materials or products you will test and their sizes; the configuration options you already know you need; and the destination laboratory's location and available services. If you are building a new fire laboratory rather than adding one instrument, say so - this apparatus is often planned together with the other instruments in its category, and a combined layout and exhaust plan is cheaper than three separate ones.