Why Heat Resistance Matters
Standard conveyor belt covers begin to soften above 60–70°C. In applications like cement clinker conveying, sinter plants, coke handling, or hot ore discharge, this causes cover deformation, rapid wear, and eventually carcass damage. Heat-resistant belt grades exist specifically for these environments.
Understanding the grade system helps you specify correctly — over-specifying wastes money; under-specifying causes premature failure.
The Standard Grades
Heat-resistant conveyor belt grades are defined by DIN 22102 and ISO 15236. The grades differ in the maximum permissible material contact temperature and the cover compound used.
| Grade | Max Material Temperature | Cover Compound | Typical Applications |
|---|---|---|---|
| T1 | 100°C | EPDM/SBR blend | Warm clinker, moderately hot ore |
| T2 | 150°C | EPDM | Cement clinker conveyors, coke handling |
| T3 | 200°C | EPDM specialty | Hot sinter, direct kiln discharge |
| T4 | 400°C+ | Steel cord + steel covers | Extreme heat — not rubber covers |
Note: T4 is a special category — at temperatures above 250–300°C, no rubber compound remains practical. T4 applications use steel cord belts with steel cover plates, not rubber. This page focuses on T1–T3 rubber-covered belts.
T1 — Up to 100°C Contact Temperature
Cover compound: Modified SBR or EPDM/SBR blend.
Ambient vs contact temperature: The 100°C limit refers to the temperature of the material contacting the belt, not ambient air temperature. An outdoor belt in a hot climate running slightly warm material might reach material contact temperatures of 60–70°C — T1 is adequate.
Typical applications: - Warm (not hot) cement clinker — clinker that has been cooled but not fully to ambient - Slightly warm processed ore - Areas downstream of hot processes where material has partially cooled
Not suitable for: Direct discharge from cement kilns or coolers where clinker arrives at 150°C+.
T2 — Up to 150°C Contact Temperature
Cover compound: EPDM (ethylene propylene diene monomer) rubber.
This is the most commonly specified heat-resistant grade for cement and coke operations. Most cement plant clinker conveyors run on T2 belts.
Typical applications: - Cement clinker conveying from cooler discharge - Coke handling at steel plants - Hot aggregate from dryers - Sinter cooler discharge (where material has been partially cooled)
Important note: T2 belts handle material at 150°C, but the belt cover itself should not be continuously exposed to ambient temperatures above 60–80°C. Infrared heat from nearby kiln or cooler structures can be an issue — consider shielding if needed.
T3 — Up to 200°C Contact Temperature
Cover compound: Specialty EPDM with higher heat stability than T2.
T3 is specified for the hottest rubber-belt applications in the cement and steel industries.
Typical applications: - Hot sinter conveying from sintering machine directly - Cement kiln bypass dust handling - Direct clinker cooler discharge where cooling is minimal - Coke oven discharge in some steel plant layouts
Practical consideration: At 200°C material contact, even T3 belts have relatively short cover life compared to the same belt in a cooler application. If your material regularly arrives at 180–200°C, expect accelerated cover wear and plan for more frequent belt inspections.
How to Determine Which Grade You Need
Step 1: Measure material temperature at the loading point. Don't estimate — measure with a contact thermometer or IR gun at the point where material lands on the belt, not in the process itself.
Step 2: Add a safety margin. Specify one grade above your measured temperature. If clinker measures at 120°C at belt loading, specify T2 (rated to 150°C) rather than T1 (rated to 100°C).
Step 3: Check ambient temperature. If the belt runs in an enclosed area with radiant heat (near a kiln, cooler, or furnace), consider this separately. Ambient temperatures above 60°C affect belt life even on T2/T3 belts.
Step 4: Consider the full belt run. A belt may carry hot material for only part of its length. The return run may pass near hot equipment. The hottest exposure point on the full belt circuit drives the grade selection.
Common Mistakes
Specifying T1 for cement clinker. Standard cement clinker from a cooler outlet is typically 80–130°C. T1 (100°C limit) is marginal at best and inappropriate if clinker temperature varies upward. T2 is the correct baseline for cement clinker.
Assuming heat-resistant means abrasion-resistant. T-grade covers are formulated for heat resistance, not necessarily abrasion resistance. Clinker is highly abrasive. You may need a T2 belt with enhanced abrasion compound rather than standard T2 cover if abrasion is also a problem — discuss this with your supplier.
Ignoring return-side exposure. A belt carrying 180°C sinter returns underneath the conveyor. If the return run passes near the sintering machine, radiant heat can damage the cover even when no material is on the belt.
Frequently Asked Questions
Can a T2 belt handle occasional temperature spikes above 150°C? Short spikes (a few seconds) above rated temperature cause surface blistering rather than immediate failure. Repeated or sustained over-temperature exposure shortens belt life significantly. If your process has frequent temperature excursions, consider specifying T3 for the margin.
Do heat-resistant belts cost significantly more than standard belts? T1 costs modestly more than standard M24 grade. T2 is noticeably more expensive — EPDM compound costs more than standard SBR. T3 is the most expensive rubber-covered grade. The cost increase is justified by the application requirement; there is no value in specifying T3 when T2 is sufficient.
Can heat-resistant belts also be fire-resistant? Heat resistance (T grade) and fire resistance (FRAS rating) are separate properties. A belt can be T2 grade and also FRAS rated, but this needs to be specified explicitly. EPDM compound does have some inherent flame resistance, but formal FRAS certification requires specific testing.
Contact Elephant Rubber
We manufacture T1, T2, and T3 heat-resistant conveyor belts in EP and steel cord constructions. If you have a hot material application and need help specifying the correct grade, contact us with your material type, measured temperature, and conveyor dimensions.