INTRODUCTION
Hazardous area classification (HAC) was originally developed to ensure that process companies select the appropriate electrical equipment to prevent the electrical ignition of flammable atmospheres. Currently, HAC is applied more widely for risk assessment purposes and to prevent various ignition sources, such as electrostatic sparks, as well as flammable substances like solvent vapors, gases, mists, and dust clouds.
As hazardous areas are presented in diverse industries, including petrochemicals, oil and gas, mining, pharmaceuticals, food processing, and power generation. HAC has been becoming crucial for assuring safety in these fields. Conducting a hazardous area classification can be challenging, as it requires in-depth knowledge of the processes and equipment involved. However, a proper HAC can greatly reduce the risk of accidents and protect the lives of workers and equipment.
BENEFITS
When performing Hazardous Area Classification (HAC), there are several benefits that facilities and plants can achieve, including:
- Safety Assurance: HAC facilitates the identification and classification of hazardous areas, and provides appropriate measures to ensure safety for people, equipment, and the working environment.
- Compliance: HAC implementation ensures compliance with safety and environmental regulations for facilities and plants.
- Risk reduction: HAC reduces the risk of accidents and disasters, minimizing damage to assets, and increasing efficiency as also cost savings.
- Reliability enhancement: : HAC increases equipment and system reliability, reducing downtime and improving operational efficiency.
- Production Improvement: HAC improves production processes, increases productivity by reducing downtime, and improving operational efficiency.
- Economic efficiency: Implementing HAC ensures economic efficiency by saving costs and enhancing competitiveness for facilities and plants.
WHAT IS A “HAZARDOUS AREA”?
A “hazardous area” is defined as an area in which the atmosphere contains, or may contain in sufficient quantities, flammable or explosive gases, dust or vapours. A fire or explosion may occur within such an atmosphere when three fundamental conditions align . This is often referred to as the “hazardous area” or “combustion” triangle.
- Fuel: This is what burns
- Oxygen: Required to support fire
- Ignition: Heat energy required to start a fire
Fire and explosion can result in catastrophic consequences for people and property causing loss of life or serious injury and possible loss of business.
HAZARDOUS AREA CLASSIFICATION (HAC) ASSESSMENT
A hazardous area classification (HAC) assessment aims to reduce the chance of an explosive/flammable atmosphere contacting an ignition source.
This is achieved by:
- Assessing the risk of fire and explosion hazards in and around installations and plants involving flammable liquids, vapours, gases and combustible dust
- Establishing zones where explosive atmospheres are expected to exist and determining the size and ignition characteristics of the atmospheres
- Categorising the minimum level of ignition source protection required for equipment to be installed or taken within a hazardous area to control the risk of a fire or explosion.
HAC ASSESSMENT METHODOLOGY
The methodology for conducting a Hazardous Area Classification (HAC) assessment typically involves the following steps:
- Information gathering: The first step is to gather information about the facility, the processes, and the hazardous materials that are present.
- Hazard identification: The next step is to identify all hazardous materials that may be present in the facility. This may involve reviewing material/chemical safety data sheets (SDS) and other documentation, conducting tests, and observing the processes.
- Hazard characterization: Once the hazardous materials have been identified, the next step is to characterize their properties, such as their flammability, explosiveness, and toxicity.
- Hazard area classification: Based on the hazard properties of the materials, hazardous areas are classified into zones or divisions.
- Hazard area drawing development: Hazardous area drawings are developed to clearly show the location and extent of these areas. The drawings may include information such as equipment locations, cable routes, and ventilation systems.
- Hazardous area equipment specification: Based on the hazardous area classifications, equipment specifications are developed to ensure that all equipment installed in these areas is suitable for the hazardous environment.
- Hazardous area equipment review: Existing equipment in hazardous areas is reviewed to ensure that it is suitable for the environment and to identify any potential safety hazards.
- Hazardous area risk assessment: A risk assessment is conducted to identify any potential hazards associated with the hazardous areas and to determine the likelihood and consequences of any accidents.
- Recommendations and report: Based on the results of the assessment, recommendations are made for any necessary improvements to equipment, procedures, or safety systems to minimize the risk of accidents. A report is prepared that summarizes the findings of the assessment and the recommendations for improving safety.
CONCLUSION
In conclusion, HACs are dynamic documents that should be regularly referred to during various activities such as new installations, change assessments, inspections, maintenance, and repairs. It is essential to conduct periodic review assessments to manage that the HAC remains up-to-date and relevant.
Hazardous area classification (HAC) is a crucial tool that supports industries to identify areas susceptible to fire or explosion, thereby reducing the risk of incidents that may result in property damage, injury, or loss of life. By implementing appropriate prevention and protection measures, HACs contribute to creating a safe working environment for personnel and equipment in hazardous areas.
