{"id":18933,"date":"2025-07-02T10:03:55","date_gmt":"2025-07-02T08:03:55","guid":{"rendered":"https:\/\/www.logic-pavia.it\/temperature-class-and-surface-temperature\/"},"modified":"2025-07-02T12:00:17","modified_gmt":"2025-07-02T10:00:17","slug":"temperature-class-and-surface-temperature","status":"publish","type":"post","link":"https:\/\/www.logic-pavia.it\/en\/temperature-class-and-surface-temperature\/","title":{"rendered":"Temperature class and surface temperature"},"content":{"rendered":"\t\t
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Risk due to temperature<\/span><\/h6>

When choosing electrical and mechanical equipment for use in potentially explosive atmospheres<\/a>, there are several factors to consider. In this article, we will explore the risk posed by the temperature generated by the equipment to prevent it from becoming a source of ignition. <\/p>

There are two distinct parameters for assessing the temperature of instruments, depending on whether they are devices for gases, in which case we refer to temperature class<\/strong>, or dust, in which case we refer to maximum surface temperature.<\/strong><\/p>

Temperature class<\/h2>

For atmospheres containing gases and vapours, equipment classification is based on a series of temperature classes (from T1 to T6), which identify the maximum permissible surface temperature.<\/p>

Temperature class<\/strong><\/p><\/td>

Maximum surface temperature (\u00b0C)<\/strong><\/p><\/td><\/tr>

T1<\/p><\/td>

450<\/p><\/td><\/tr>

T2<\/p><\/td>

300<\/p><\/td><\/tr>

T3<\/p><\/td>

200<\/p><\/td><\/tr>

T4<\/p><\/td>

135<\/p><\/td><\/tr>

T5<\/p><\/td>

100<\/p><\/td><\/tr>

T6<\/p><\/td>

85<\/p><\/td><\/tr><\/tbody><\/table>

Each flammable substance has its own minimum ignition temperature: to be safe, the equipment must have a surface temperature below that value. Below is a table containing some examples of temperature class and permitted product combinations: <\/p>

Temperature class<\/strong><\/p><\/td>

Max surface temperature (\u00b0C)<\/strong><\/p><\/td>

Examples of gases<\/strong><\/p><\/td><\/tr>

T1<\/p><\/td>

450<\/p><\/td>

Hydrogen (\u2248 500 \u00b0C)<\/p><\/td><\/tr>

T2<\/p><\/td>

300<\/p><\/td>

Acetylene (\u2248 305 \u00b0C)<\/p><\/td><\/tr>

T3<\/p><\/td>

200<\/p><\/td>

Pentane (\u2248 240 \u00b0C)<\/p><\/td><\/tr>

T4<\/p><\/td>

135<\/p><\/td>

Ethyl ether (\u2248 180 \u00b0C)<\/p><\/td><\/tr>

T5<\/p><\/td>

100<\/p><\/td>

Highly flammable solvents<\/p><\/td><\/tr>

T6<\/p><\/td>

85<\/p><\/td>

Carbon disulphide (\u2248 90 \u00b0C)<\/p><\/td><\/tr><\/tbody><\/table>

Maximum surface temperature<\/h2>

For atmospheres with dust, two distinct scenarios must be distinguished (as reported in technical standard EN\/IEC 60079-31:2014):<\/p>