Firefighters' clothing is rated by the thermal protective performance test: a specimen of the full garment composite - outer shell, moisture barrier and thermal liner together - is exposed to a combined radiant and flame heat flux, and a copper calorimeter behind it records the temperature rise. The trace is compared with the Stoll criterion for second-degree burn prediction, giving the TPP rating that NFPA 1971 sets minimums for. The Motis TPP tester is built to ISO 17492 and NFPA 1971, and the range extends to the related radiant (RPP, ISO 6942), heat transfer index (ISO 9151) and contact heat (ISO 12127-1) methods.
How the Thermal Protective Performance (TPP) Tester works
The specimen composite is mounted over the calorimeter assembly and exposed to the combined heat source at the standard flux. The sensor temperature is recorded through and after exposure; TPP value is calculated from the time at which the recorded curve intersects the burn-injury criterion, multiplied by the exposure flux as the method defines.
Key specifications
| Standards | ISO 17492, NFPA 1971 for TPP; related configurations: RPP to ISO 6942, HTI to ISO 9151, CHT to ISO 12127-1, molten metal splash to ISO 9150 / ISO 9185 |
|---|---|
| Specimen | Fabric composite systems as worn (shell + barrier + liner) |
| Measurement | Copper calorimeter temperature rise evaluated against the second-degree burn criterion |
What the test reports
- TPP rating value
- Time to predicted second-degree burn under the test exposure
- Comparative data across composite constructions
Applications
PPE manufacturers and their fabric suppliers iterate garment composites on this instrument; certification laboratories run it for NFPA 1971 structural firefighting ensembles. See the PPE fire test equipment page for the full ensemble-level range, including flame manikin and helmet/glove tests.
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.
TPP or RPP - which applies to my product?
TPP uses combined radiant and convective exposure and is the NFPA route; RPP (ISO 6942) is radiant-only and appears in European specifications. Many PPE laboratories run both; tell us your target standards and we will configure accordingly.
Can it test single layers as well as composites?
The methods are written around the composite as used in the garment, but single-layer testing is routinely done for development comparison. The specimen holder arrangement is confirmed for your use case at quotation.
Configuration, installation and support
Every Thermal Protective Performance (TPP) Tester 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 ISO 17492, NFPA 1971. 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 Thermal Protective Performance (TPP) Tester correctly the first time, send: the standard and edition you will test to (ISO 17492, NFPA 1971); 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.