Analyze an SDS

Glossary / Physical properties

Boiling point

Boiling point is the temperature at which a liquid's vapor pressure equals the surrounding pressure, so it changes rapidly to vapor. SDSs usually quote it at normal atmospheric pressure, and a low boiling point generally signals a volatile material.

Explanation

A liquid does not have to be boiling to give off vapor, but the lower the boiling point, the more volatile the liquid generally is and the more vapor it gives off at room temperature. That is why boiling point goes hand in hand with Vapor pressure and Evaporation rate. Mixtures often boil over a range of temperatures, and the SDS may give an initial boiling point and a range.

For flammable liquids the initial boiling point is a classification criterion. OSHA and GHS use it together with Flash point to place a liquid in Category 1, 2, 3 or 4. A liquid with a low initial boiling point and a low flash point lands in the most hazardous category.

Boiling point also affects process safety. Heating a liquid near its boiling point can produce large vapor releases, pressure in closed vessels and splashing or flashing when a hot liquid is released. Pressure and altitude change the temperature at which boiling occurs, so vacuum operations boil liquids at lower temperatures than the SDS figure.

Some materials decompose before they boil, in which case the SDS may state that the substance decomposes or give no value. Check Section 10 and Section 5 for hazardous products formed when heated.

What to do and watch for

  • Be careful with liquids stored or used near their boiling point, especially in closed systems.
  • Allow for pressure relief when heating volatile liquids in sealed equipment.
  • Check for decomposition information if the SDS reports no boiling point.

Where it appears on an SDS

SDS content and wording vary by supplier. This page is general reference and does not replace the current SDS for your product.

Related terms

Related reference pages

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