This document details the general considerations for the correct specification of pre-engineered DFE Systems for the protection of Unoccupiable Cabinets / Enclosures of Gross volume up to 2m³. Such Cabinets / Enclosures may be single or multi-compartment and may include free vent areas or airflow. It is intended to cover IFE Systems that fall outside existing fire extinguishing standards and provide guidance on what equipment manufacturers should consider when they assess, specify, design, manufacture and supply an IFE System for this specific application category. It should also provide a guide for responsible persons and specifiers as to what information they should require of manufacturers and service providers, to confirm the suitability of an IFE System being offered. The standard allows use of any recognised extinguishing agent and allows total flooding or local application solutions to be proposed, as appropriate to the fire risk, fire class and specific application conditions that are being considered. Fire Extinguishing Systems designed in accordance with this standard may typically be used for protection of Unoccupiable Cabinets / Enclosures such as those found in, for example, the following applications: • Electrical Enclosures. • Laboratory Fume Cupboards • Machinery Spaces • Flammable Liquid Stores • Machine Tools There are other fire risks that can be classified as Unoccupiable Cabinets / Enclosures, where other adverse conditions may also require a non-standard solution. These DFE Systems are intended solely to provide enhanced local fire protection for Unoccupiable Cabinet / Enclosure applications. They are not intended for use as whole room or building fire protection systems, which are covered in other applicable standards.