Hazardous Area Classification

AS/NZS 3000 Clause 1.4.15 defines a hazardous area as a three-dimensional space where an explosive atmosphere is present or may reasonably be expected to be present in quantities that require special precautions for the construction, installation, and use of equipment.

If a source of ignition with sufficient energy is introduced into an explosive atmosphere, it can trigger a fire or explosion. Such events can have devastating consequences, including loss of life, serious injuries, environmental damage, and destruction of assets. Additionally, they can severely impact business operations, tarnish reputation, and lead to financial losses or even business closure.

A Hazardous Area Classification (HAC) study aims to identify and classify areas where flammable gases, vapors, mists, or combustible dust may be present, ensuring the correct selection and installation of equipment for safe operation in such environments.

The classification process considers key ignition characteristics, including gas group (ignition energy) and temperature class (ignition temperature), to mitigate fire and explosion risks effectively. It is conducted in accordance with relevant international and national standards, such as IEC 60079, AS/NZS 60079, and API RP 505 (for classification of hazardous areas in petroleum facilities), along with other applicable industry regulations, to ensure compliance and safety.

The source of release method (also known as the direct example method), as outlined in AS/NZS 60079.10.1:2009, is a commonly used approach for determining the likelihood and extent of hazardous atmospheres in a facility.

However, more rigorous techniques, such as gas dispersion modeling using specialized software like Phast DNV, or quantitative risk assessment (QRA) methods, can also be employed to provide a more detailed and accurate determination of hazardous area extents.

As per AS/NZS 60079.10.1:2009, no modifications to equipment or operating procedures should be made without prior approval from the responsible person authorized to verify hazardous area classifications and maintain necessary records.

Additionally, hazardous area classifications should be reviewed periodically throughout the facility's lifecycle to account for changes in equipment, processes, or operational conditions that may affect hazardous area extents.

We provide hazardous area classification (HAC) services for new facilities and offer review and update services for existing facilities. Regular updates are essential when changes to materials, processes, or equipment occur after the original design to ensure ongoing compliance and safety.