Hazardous Area Classifications In South Africa
Many people do not know that, where flammable or explosive products are being stored or processed, the storage vessel itself is not the only source of risk. Due to vapour emissions from flammable products from spillages, vents, or leaks, a flammable atmosphere can develop within the vicinity of the product. Often, these flammable atmospheres cannot be seen or smelt, so employees do not even know there is a danger. When flammable atmospheres have developed in an area where there is sufficient oxygen, it just takes a small spark such as that within the terminals of standard electrical equipment, or static electricity, to cause an explosion. The consequences can be fatal and highly destructive for businesses. For this reason, it is a legal requirement according to the Occupational Health and Safety Act and South African National Standards such as SANS 10089-1 and SANS 60079 to classify the flammability of an area where flammable products are stored, transferred, or processed.
A hazardous area is defined as an “area in which an explosive atmosphere is present, or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus”. Once a hazardous area has been classified, electrical equipment can be appropriately selected and installed to ensure operations within a hazardous area will not result in explosions or fires due to flammable vapour igniting. For example, standard three-phase electrical motors are often “spark-proofed” to be suitable for a zone 2 hazardous area classification, or “flame-proofed” to be suitable for a zone 1 hazardous area classification. Businesses storing, transferring, or processing flammable products need to know the boundaries of the hazardous areas on their premises to ensure their electrical equipment is adequately protected.
It is also important to know that it is not only vapours from liquids that produce flammable environments. Finely divided solid particles (dust) from various processes can form explosive environments when mixed with air at atmospheric pressure and normal temperatures. For example, process powders or flour can create an explosive atmosphere when mixed with air. It is therefore very important that businesses storing, transferring, or processing flammable substances ensure that hazardous area classifications are correctly done.
Benefits Of Using DonTech
We provide a professionally registered Mechanical Engineer to conduct and sign off designs for hazardous area classifications.
DonTech has extensive experience in developing hazardous area classifications for various products that form flammable vapours or flammable dust environments.