A code-compliant generator installation will require secondary-containment for fuel storage tanks as well as for fuel-oil piping that is in direct contact with the soil. Such outdoor tanks and piping systems will be equipped with release detection devices, but once the piping enters the building, how is it monitored for leaks?
In most interior installations, fuel-oil piping consists of single-wall threaded black-iron pipe. Interior piping is usually run above the finished floor, on racks overheard or tight against a wall. Sometimes this piping will run in a concrete trench, traveling from the interior/exterior wall, across the room, and toward each engine. It then rises above the finished floor to connect to day tanks, and later to the engines, via flexible connectors. Any leaks in this single-wall piping may be identified by visual inspection, but in most cases, by electrical monitoring of “low point” collection sumps that are equipped with a leak sensor probe. Considering that generator buildings can consist of many large engines, each consuming several gallons of fuel per minute, it should be evident that any fuel line rupture inside the engine room can lead to a substantial amount of fuel on the floor. Depending on the room’s design, it could be several minutes before a fuel spill reaches the “low point” collection sump, where it may then be detected by a sensor probe.
Instead of waiting for the spilled fuel to make its way to this collection sump, is there a quicker way to detect a fuel spill, perhaps detecting it as soon as it makes contact with the floor? Well, yes, there is a way!
Sensor cables are a continuous string of a specialty cable, designed for installation in a space to monitor and detect the presence of a fluid. A sensor cable is connected to a monitoring console. This console is in continuous communication with the sensor cable, and once a leak is detected anywhere along the string, the console will provide information on the precise location of the leak, the persistence of the leak, and the magnitude of the leak. The sensor cable can be a non-discriminating type, which will activate a fault when it detects any fluid, or it can be a discriminating type, which only responds to a certain type of fluid. The latter type can be specified to only respond to contact with hydrocarbons, which makes it ideally-suited for detection of diesel fuel.
What happens when a fuel leak is detected?
Using a leak detection system console, such as the PAL-AT console, you can take action immediately after a release detection event. Depending on the installation, you may choose to stop the affected engine, stop the related fuel transfer pumps, or simply alarm the condition to the facility’s manager.
With a hydrocarbon-sensing sensor cable installed in the floor space around the footprint of the generators and day tanks, you can have a system that will detect fuel much sooner than would be the case with any other traditional method. Aside from the quick detection, this system will also assist the owner in quickly determining whether a leak is a small nuisance leak affecting a few inches of the sensor cable, or a major leak in contact with a large section of the sensor cable. When the system is installed in an unmanned site, which relies on remote monitoring, this level of detail can be extremely valuable.
Would you like more information?
- Have an up-close look at a set of shop drawings and plans for a recent installation at the Barnes-Jewish Hospital in Missouri.
- Learn more about the PAL-AT system, and the TFH-Gold leak sensing cables.
- Call our office for support with design and product selection questions for your next project.