Industrial Fire Familiarization: Process and Products (Part 1)
Some of the largest hurdles to clear when becoming an industrial firefighter are understanding how process equipment works, and what exactly we are making. The knowledge of how different pieces of process equipment work, I believe, is vital to the success of an industrial responder. Being able to identify what a piece of equipment is, and its basic mechanics, will give us a much better understanding of where failure is prone to happen, and what exposures will behave like during fire situations.
To get a firm, general understanding of process equipment we must take each lesson and break it into much smaller, more manageable pieces. This particular lesson, we will focus on process pumps, a brief overview of how they work, and their basic construction. Pumps and compressors encompass some of the most vital forms of equipment in refining today. Whether is moving liquid, or vapor, this equipment generally makes this possible. As responders, we need to be able to identify these pieces of equipment, and also identify common failure points and hazards. Let’s begin with basic pump construction.
Generally, we use drivers of two kinds in the refining business; Steam powered, and Electrical powered. The driver, is what makes the pump spin, or otherwise “work”, depending on the type of pump. Spotting an electrical motor is pretty straight forward, as there are usually large junction boxes, or other wiring ran to the equipment. The hazards associated with this type of driver are pretty straight forward as well – VOLTAGE! Steam powered drivers or “turbines” are sometimes a little harder to spot being as both sides of the equipment will have associated piping (one being the process pump side, one being the stream driver side) that blends in. Steam turbines will usually have insulated lines warning of heat or steam. Our focus as responders needs to be identifying if the equipment is electrical or steam driven, as this will give us incite to hazards that will present themselves upon approaching. For large electrical motors, it is vital water spray not be directed into the equipment if it is still energized. Just as in a residential fire, we must secure power, if safe to do so, before water based extinguishment begins. For steam turbines, we must be wary of rapid cooling of the turbine casing itself, as this stress may lead to cracking or other breaking of the casing itself, leading to a steam leak which only further complicates our mission.
While a driver spins or otherwise drives the pump to do its work, the process fluid travels through the pump casing. Inside of a pump casing there can be many different types of “Pumps”. Centrifugal pumps are very common in industry as well as the fire service, as we use them on our engines daily. While positive displacement pumps may not have a standard look about them, there are many similarities and failure points that are in common. These common points are the pipe connections for the process fluids running through the pump, and the seals located on the case itself. Pipe fittings are a common failure point because when under tremendous heat, these sections are usually the weakest. As we have discussed before, the different types of pipe fittings can be either flanged, welded, or screwed. Also located around the pump casing are the pump seals. These seals prevent process fluid from leaking into the atmosphere. As many processes run well above auto ignition temperatures of products, a leak of any size can become quickly catastrophic. While there are MANY types of pump seals in use today, as a general understanding of this common failure point, lets discuss where it is located. The pump seal itself is where the outside shaft enters the pump casing itself, and connects to the impeller or other pumping device inside the casing. The seal is there as we said to prevent leakage into the atmosphere, as this is where that interface is happening. Pump seal fires are some of the most common issues we face as industrial responders, and being able to spot them during day to day operations gives us a leg up on the emergency.