Tank Blasting Project Sites

With fuel storage it is very important that the internals of the tanks are coated. The reason for that is that fuel and oil is lighter than water, so all the water drops to the bottom of the storage tank and it is very corrosive. The bottom area of a tank is often contaminated with "chlorides"...in other words, "salt", particularly in crude tanks so it is very, very corrosive. What that means is the tank floor and normally 3 ft up the walls is coated.

It is crucial that surface preparation is top class, to avoid re-work and costly "tank-downtime" to re-coat a failed tank floor. And, it may be the Contractor who pays!

The most common types of abrasive used are GMA Garnet, Coal Slag and Copper Slag. Sometime with large flat floors we use shot blast machines with steel grit and shot, but that is only cost effective in limited circumstances.   The abrasives that are better than others, generally achieve a more consistent finish, a high quality service cleanliness and a more consistent profile, the best abrasive available is GMA Garnet.  Part of the reason for that is you often have some coating failure.  The tank floors can be ¾- 1” or 1¼” thick plate you will get some pitting.  The GMA Garnet has the right amount of fine grains in it to actually clean out the pits properly, so there are not corrosion deposits left in the pitting.

One major uncontrollable challenge is the inclement weather. There are not many ways to handle weather issues, except to use a Dehumidifier and to ensure that your blasting equipment is high production to ensure you can make use of every hour of favorable weather.  Using a dehumidifier is a key part of doing the internals of a storage tank, because you want to blast for several days at once you need to make sure that the weather conditions are favorable.  You need to be very organized because the tank is out of service so the days on the job are crucial, so if you can save time you’re far better off, but if you run over time you often end up with penalty rates. 

The access around the tanks is often a challenge because you have to go around and bund the walls and run extra hoses.  Because you often have equipment one side of the tank you may not be able to get to the other side of the tank.  The tank could be 250 ft across so you’re having to run hoses all the way in and around across the tank which means you’re having to cope with pressure loss in blasting and also painting. Work in refineries also needs to be rated equipment.  If you are working in a construction area it is very muddy and you have equipment getting bogged. 

Always remember that a tank is a confined space, you need watchers, people with intrinsically safe radios and communication systems.  You need to get people in through manholes, manways, as well as get past ductwork hoses, so it’s a tight access environment.  You need to make sure your people are safe, and make sure you’ve got people checked in and checked out.