Before products, equipment, or protective systems can be selected for installation in a Explosive Atmosphere they should first be certified as being suitable for that application. A Certificate of Conformity for equipment intended for use in Explosive Atmospheres is evidence that the product, equipment or protective system conforms and has been tested to a relevant standard. The Certificate of Conformity will clearly show the standards to which the test were carried out, and which edition of the standard was used, and it should also provide a schedule describing the apparatus and any variations or modifications that have been approved. The Certificate of Conformity should endorse the type of equipment proposed to be used as being safe for its intended use, with any Special Conditions for Safe Use, if applicable, clearly spelled out within the document.

It should be noted that the certificate alone does not make an installation safe, and there is an obligation on the part of the installation contractor and / owner to ensure that the apparatus is installed correctly, in a competent manner, and in accordance with the manufacturers instructions, taking into account any special conditions for safe use that may exist.