Life inside a modern refinery can be a dangerous place. Some of the jobs that we see on a daily basis can make even the most seasoned HAZMAT vet squirm. After talking to a few of my colleagues, I compiled a list of 4 of the most dangerous jobs we see out in the plants today, in no particular order.
In certain circumstances, it becomes necessary to install bypasses, valves, or other fittings on lines that are currently in service. With product flowing through the line, this can pose a few logistical issues. Without shutting the line down, a hot tap becomes our available option. Without flow cessation in the line, a saddle is welded around the outer diameter of the piping, with a flanged surface, and valve attached. A “Hot Tap” machine is then flanged to the valve, and valve then opened. With flow through the line, a cutting head bores through the live line, providing access to the product without interrupting flow. Once the head is retracted, the valve is then closed, and hot tap machine removed.
Inert confined space entries
Any time an entry into a confined space is needed, there are many factors we take into consideration. One of the most important aspects we monitor is the air composition. Through cleaning, air movement, and neutralization, we can ensure a safe entry under many circumstances. However, in some extreme cases, an atmosphere conducive to life support, may not be our friend. It is not uncommon to work with catalysts and other products that are pyrophoric. A massive reactor full of pyrophoric catalyst won’t be too friendly when we pop the manway and begin to clean it out. In this situation we use an inert atmosphere. Through the use of nitrogen or other inert gases, a constant flow is purged on a vessel, thus dropping the oxygen content to zero. Many specialty companies are trained to make entry to clean out materials under these atmospheres in what some may describe as space suit looking PPE. Many safety interlocks are in place, like dedicated communication systems, and video monitoring of the activities to ensure everyone goes home.
Flares can be used for many different things in the process world. The most common use for flares, is process relief. All of the equipment, and line, are controlled at certain pressures to control fluid movement and chemistry. When the pressure is exceeded, for whatever reason it may be, relief valves are designed to open, and relieve excess to the flare system. Pilots are burning at the top of the flare stacks, and the vented gas is burned. Many different units or processes can be tied into one flare system, and this is where maintenance becomes a little difficult. If a section of line, a valve, or other piece of piping related to the flare system must be taken out of service, for the safety of everyone else tied into it, the flare can not be shut down. A flare job is any work that must be done on the live system. Many hours go into planning these jobs, because when a line is opened, you are currently at the mercy of all other processes connected to that line. Maintenance workers generally wear full PPE including chemical suits with SCBA, to bunker gear depending on the processes that tie in to the line. In some cases industrial fire department standbys are performed.
Live line welding
Whether it be for hot tap installation, wrappers, or other repair purposes, it sometimes becomes necessary to weld on live process lines. Nothing makes us feel more warm and fuzzy inside than hearing about hot work on live lines being conducted that day. The process may be different from facility, to facility, however a few general steps are taken to ensure safety. Where ever the weld or repair is to be made on the live line, an X ray or other type of inspection process is conducted. Metal thicknesses are recorded and given to the welders themselves so they are aware of the thickness they are working with. The next item to be monitored, is the flow itself in the line. This is where engineering comes in to play. For the amount of work being performed, a positive flow must be constant to help displace heat buildup on the line. The conducted heat is carried away by the flow, be it gasoline, diesel, jet fuel, whatever is inside. When we can achieve a verifiable flow, know our thickness and scope of job, the next requires steady hand. Welders will take an arc to the outside of a line carrying some of the most flammable or toxic substances on earth, with nothing but training and experience to guide them.
These jobs can happen everyday in industry. Next time your out with the industrial guys in your area, let them know how much you appreciate them defending your hometown from these hazards