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Drilling Rig Safety During Lightning Storm
Storm season is here in Oklahoma as well as across the country. When I see lightning in the distance and and feel the thunder rattle the drilling rig, Instantly I wonder, "Am I protected from these lightning strikes on a drilling rig?"
In Oklahoma our News Stations have all the latest equipment and technology to predict and understand these storms so I sent the following email to all 3 Major Stations and their Meterologists. Not surprisingly the only response came from Gary England with KWTV 9 in Oklahoma City. He has been Oklahomas most revered authority on storms for as far back as I can remember.
Here is the text of the email
"Hi Gary ,I have a website for oilfield workers and want to write a safety meeting over being safe on drilling rigs during Thunderstorms. We have all always been told we are safe in cars because we are not grounded. well, on a Rig, with several miles of drill pipe in the ground, we are definitely grounded! We don't; usually stop for storms,drilling rigs are iron and we always worry when the lightning starts striking around us! Can you comment on this subject for all of us? "
Gary England responded that he was directing the question to his Meterologist Carrie Rose for research and that I could expect an answer back in a few days.
In a week I received this response
"Hi Curtis, You are right, the drilling rigs are grounded. The problem is that much of the exposed surface of it that the workers touch is metal. The workers need to get as far away from touching the metal surfaces as possible. Another example similar to this is a highway overpass. The overpass has metal in it and it is grounded. If struck, the lightning will likely safely pass to the ground. However, you can't touch the metal parts of the overpass if you are seeking shelter underneath it. Move as far away from the metal parts (like the girders), stay on dry surfaces.
So for you guys, I don't know if it would be effective to build "Safe Spots" all over the rig which are not metal. Maybe enclosed safe rooms the guys can go to when there is lightning. Protective suits and gloves might provide sufficient protection if they must continue touching and standing on the metal, but I'm not sure how feasible that option is for you.
Your car example you mentioned is good, but you're inside the car, not outside it like you would be on the Rig, and that's what helps keep you safe; the lightning is conducted around you. When you're on the rig, you're outside touching the metal, making you a part of the conducting system (like if you stuck your finger in the ignition key inside the car, or sit on the hood of the car outside).
Even though the rig is well-grounded, lightning discharges do not always follow the path into the ground. The lightning can fan out along the surface of the ground as well, which is dangerous for anyone working outside at the time of the strike.
You can increase your protection against this happening by using radial conductors buried just below the ground surface, extending about 30 feet from the bottoms of the drilling rig conductor.
So basically, if you're on the rig touching metal, or even near the rig exposed to the open, you are at risk. If you're touching the grounded metal, you are a conductor along with the metal.
I hope this information helps, but you guys are really in a difficult situation. The safest advice is to stop working on the rig and seek shelter inside a building or car (not touching metal surfaces in the car!). But I also understand the economic demands on the business. If you remain on the rig touching metal, you're taking your chances.
Please do not hesitate to contact me if you have any further questions, or if I may be of any assistance.
Regards,
Carrie Rose,
Meteorologist News 9 Weather Producer
The answer brings up as many questions as it addresses, but there are several things I can do to provide myself with additional protection
- My next pair of Redwing work boots will be equipped with soles used by those of electricians
- I will be finding a thick rubber mat like those we use on the rig floor, for inside the Doghouse for myself and my hands to stand on during a Lightning storm
- I will get my Derrickman down from the board during a lightning storm
Contact your Safety Director as to guidelines to follow during a Lightning Storm.
This from "Ryan" in email;
I recently read your safety meeting on lightning strikes and would like to provide you some information that I learned years ago and then later when I became an electrician and learning electrical theory I was reassured in what I had learned previously.
First of all lightning is millions of volts and extremely high amperage. These two attributes allow lightning the unique ability to arc thousands of feet, please keep in mind that air is one of the best insulators known.
I wish I still had it but one of the electrical utilities had how many feet apart electric lines had to be in order to keep from arcing together at different voltages, but to give you an example high voltage carrier wires may run something like 20,000 to 30,000 volts, they are bare (no insulation) and only about 8 feet apart.
Now lighting is arcing thousands of feet through free air, and it is not do to moisture in the air or else standard electrical lines would arc the same way, do you think that a 1/2 inch of rubber in the tires insulates you well it doesn't.
What happens is that electricity, like water follows the path of least resistance. By staying inside a vehicle the electrical current flows around you through the structure of the vehicle unless by some chance you became a lesser resistive path.
On a rig you have a huge lighting rod standing up in the air. The frame work of the derrick provides for a less resistive path to the ground than the air does so more than likely lighting will hit the tower. Theoretically you could stand on the floor during a strike and not be effected however electricity generates massive amounts of heat so therefore the side effects, if you will, could cause signifcant damage.
The key to keeping electricity from killing you is to make sure that it does not pass through vital organs. So probably the best place to be would be in the dog house sitting on the benches or to be kneeling down without your back, hands, arms or head touching. This will limit any stray current from passing through your vital organs.
The reason that there could be stray current is that if there is not enough metal around you for all of the current to pass readily around you in that split second than some could find alternative paths such as yourself. If this happens you want it to pass strictly through your legs.
Another thing if your rig has an upper and lower dog house like ours, your better off to be in the lower dog house due to heat. If you ask why I think one should be in the dog house rather than away from the rig is two reasons, one is heat, the dog house will provide a small amount of insulation as well as disapation of heat and two, if you look directly at a welding arc you can go temporarily blind just think what a million volt welding arc could do.
Hope this helps
Ryan R.
