Lately we’ve been spending some blog space working on the very preventable workplace hazard of workers and drivers around tanker trucks that we see on the roads all the time, carrying oil, natural gas, fertilizer, and other materials that have hazardous or dangerous risks to them.
Tanker truck incidents are relatively rare compared to may other types of incidents (including those on constructtion sites), but what Albert Weaver III and Cynthia Sink wrote about in Professional Safety magazine was the sad reality that some simple devices can drastically eliminate very preventable deaths and serious injuries from workers or drivers falling or slipping off the top of these tanker trucks, especially during the loading and unloading processes.
While these kinds of incidents are not common, they can be very expensive in time-loss events and medical expenses through workers’ compensation when the incorrect or lack of safety procedures or tools are employed. Weaver and Sink wrote an extensive article that focused on a main tool that could greatly reduce these unfortunate accidents – fill gauges that can be read from ground level.
You see, many of the workers who are severely injured or killed from falls off the top of tanker trucks, are usually on that truck to visually assess the level in the tank to ensure it does not get too full. And falls from a higher level to a lower one is one of the top reasons for workplace incidents. The real issue is that, in reality, workers and drivers really have not had to be on top of trucks for at least the last 30 years – that is how long fill gauges have been in regular use, and in the decades since they have become less expensive, more accurate and more specific to various industrial needs and uses.
In this post we’ll briefly go over six different types of fill gauges for tanker trucks, most of which could be retrofitted into existing tanker trucks so drivers and workers cna monitor the fill process safely. And the cost of these fill gauges are easily justified as investments compared to the cost associated with a worker getting injured or killed from a fall because they just had to check the fill level visually from the top of the truck.
Each of these fill gauge types are commonly available and in use, and they are separated by a few technical characteristics, but all of them have high levels of accuracy where it will be virtually unnecessary for a worker to climb onto the truck to “confirm” the reading. Let’s touch on each of these gauges.
- The sight-eye gauge.
Perhaps the lowest-cost and lowest-tech gauge tin common use, the sight-eye gauge can be welded into the side of a tanker truck. Most tankers will have three of these gauges, welded at the bottom, middle and near the top of the tanker to show the fill level and each of the three areas of the tanker. This will not be confused with the next type of gauge because a sight-eye gauge has a glass or plastic bowl-shaped design to it.
- The sight-tube gauge.
This gauge has some assembly and installation requirements to it, which makes it a bit more expensive than the sight-eye gauge, but it can be just as accurate as long as you are using it on a tanker that does not haul liquids that are too viscous, or the tanker is being used in warm-weather areas (the liquid in the gauge can freeze). Most tankers will only need one of these gauges, and it has a tube that sticks out from the truck and thus could be subject to adverse impact or breaking.
- The threaded-rod gauge.
This kind of gauge is welded to the top lip of the tanker hatch and is threaded by brass or other washers thatare non-sparking or not iron-based. These washers are on the rod at the location where the cargo would be at the max fill point.
- The float gauge.
This is another low-tech option for cargo tanks, especially those with liquid cargo. A float on the surface of the liquid is connected to a rod that feeds outside of the tank, and an arrow attached to the exterior end of the rod moves up and down according to the level of the liquid. This gauge can cost more than $300 after installation, and the accuracy could be affected if a coat of resin gets on the float (which means you must be mindful of the material that is being loaded).
- The load cells gauge.
One of the more expensive gauges but also more accurate than most, a load cell gauge is used to measure strain on the framework of a tanker when a material is being loaded. Load cells can cost upwards of $10,000 and cannot be retrofitted, as they must be part of the tanker structure and support. The amount of fill is determined by weight, taking into account the gravity of the liquid being loaded and the empty weight of the tanker.
- The guided wave radar gauge.
Just the name seems fancy, and this one does not disappoint. As the name suggests, microwaves are sent out along a guiding rod or cable that sends pulses to the surface of the liquid as it fills the tank. The pulses are read by radar to determine the amount of empty sace in the tanker, and the cable can be set up to indicate when the fill level is reached as the empty space drops to a certain point.
The final post of this series (you can read the others here | here | here) will go over costs and benefits of these gauges, and deliver some guidance from the U.S. Department of Transportation regarding tanker safety and the use of fill gauges.