Dynamic elaboration on the Art & Science of Hazardous Area Protection
More about Ex …for the non-Ex
Let us start our discussion-of-the-day with a cup of coffee & a good breakfast. Of course we will have to prepare it first. Kitchen is the place specially designed and fabricated for this purpose. The basic hardware , required is:-
1. A Gas Stove (Flammable Material)
2. A Match-box (Ignition Source )
3. Air (The required component is Oxygen)
A proper combination of these 3 components will act as a heat source and …and once this process is safely accomplished…. we can continue with the next remaining steps of brewing our coffee and preparing our breakfast. If we contemplate……….. during our breakfast, on the fact that a combination of 3 components always results in fire, then we can represent this fact graphically in form of a triangle. Each corner (Called vertex in geometry) representing a corresponding components Let us call it FIRE TRIANGLE.
And all fires exist by virtue of FIRE TRIANGLES.
The fire in our Kitchen gas Stove is 100% controllable though the adjusting knobs on the cooking-range, from Zero (No-fire) to 100% Flame. (This triangle does not exist in ELECTRICAL Ovens, but a pot left unattended on any of the heat-plate can generate a FIRE TRIANGLE in itself… • With electrical heat-plate acting as a ignition source • The pot material (plastic handle or the plastic lid-handle) will act as flammable material • The surrounding air will provide the OXYGEN for…Burning the plastics of the pot) The presence of fire triangles in our Kitchens does not bother us and we take the built-in safety for granted. The built-in safety exists in the following components:-
1. The gas cooking range (Branded & guaranteed)
2. The Gas connection (Approved, installed & maintained by the Gas Utility)
3. The Over-all kitchen design with good ventilation (Failure of any of the built-in safety can generate devastating consequences).
On to the next example . The fuel dispensing stations (Petrol / Diesel / Gasoline or Compressed-Natural gas or CNG ) are all places filled with Fire Triangle forming components. Ready to generate Fire Triangles and ….FIRE. The 3 components are easily recognizable:-
But most of us , don’t even think about all this and just pull-in our vehicle for refueling. But all of us must have noticed the “NO SMOKING” sign along with other Warnings like NO MOBILE PHONE OPERATION DURING REFUELING STOP YOUR CAR ENGINE DURING REFUELING …….similar signs for the CREW working at the Station. Like CHECK EARTHING CONNECTION BEFORE CONNECTING THE PIPES TO THE LORRY…etc. All these signs clearly indicate that there is a hidden (underlying) PROTOCOL …Safety Protocol , to be exact, which is being followed. ….since this PROTOCOL deals with the CHEMICALS & ELEMENTS & HEAT ENERGY without giving any chance of formation to the FIRE TRIANGLES…It must have been effective, strong , practical and well designed . There is no doubt about that ! One of the important set of document which forms the basis of this Safety Protocol is IEC 60079. At this point let us get familiarize ourselves with the following term Hazardous Area . An area where flammable material is present in such quantities which in mixture with oxygen can cause an explosion when ignited. (Let me add our concept of Fire Triangles to it …Hazardous Area is filled with materials ready to form FIRE Triangles) The logical safety plan should be : STOP the formation of FIRE TRIANGLE. Take care so as not to let the 3 components join or connect or contact . An so it is.. ….now on to the next BIG example. Its a Refinery .Petroleum Oil Refinery. (An industrial facility which converts crude oil into high-octane motor fuel (gasoline/petrol), diesel oil, liquefied petroleum gases (LPG), jet aircraft fuel, kerosene, heating fuel oils, lubricating oils, asphalt and petroleum coke. (Wikipedia) ) Of course ..we can only have access to the offices ….and will not be allowed to go inside the plant/process area . The Offices are The non-Hazardous Areas and the Process areas is the Hazardous Area. (An approximate & very simple plan of an Industrial Facility processing flammable materials is as follows:-)
Some underlying Principles
(Interestingly, its IEC , this time its IEC 60079-14-2013 , which gives us a short account of the base of the preventive measures to reduce the explosion risk from Flammable materials.)
The 3 principles are :-