With the advanced technologies that wall scanners present today, when purchasing them it is important to know our requirements to know how to make the correct choice. The idea lies in deciding on a device that really helps us if, for example, we work in the installation of heated floors or that does not generate excessive costs if what we are looking for is, mainly, the precise detection of beams and studs.
To do this, it is convenient to consider a series of factors that we detail below.
Building type
Traditionally, construction in various parts of the world has always been based on bricks (solid or hollow) and concrete. However, it has been almost a century that many countries and regions have mainly used dry or dry construction. Drywall because it brings together a series of advantages, since it is anti-seismic, economical, flexible and resistant to fire and humidity. Construction Drywall It is carried out on wooden frames, therefore, when drilling holes on this type of wall, it is important to locate the location of the beams that make up these frames, either the edge or the center of the beams.
The type of building with which we will work is, therefore, the first indicator to choose the wall scanner adequate, since if we mainly need to locate wooden beams in a construction Drywall, most likely a simple beam detector is more than enough, considering that many also locate live metal and electrical cables. If, on the contrary, we work with masonry constructions where metal and live electrical cables are mainly hidden, the wall scanner more economical will be ideal.
Technology type
Consideration of the type of building will also determine the type of technology used by the wall scanner, and therefore, the cost of this. The type of technology to choose depends on the thickness of the wall and the density of the material. Cheaper scanners, which employ ultrasonic technology, tend to perform better on walls in Drywall thick or double, due to its ability to bounce off neighboring areas. In contrast, wall scanners with electronic technology work better with thinner walls, for example, plaster, and also all provide the possibility of detecting ferrous, non-ferrous metals and live electrical cables with greater precision. On the other hand, if our requirements are more complex and we must locate deep objects knowing how deep they are or we need to locate plastic water pipes, it will be highly recommended to purchase a wall scanner with radar technology.
Figure 1-Detection in heated floors with wall scanner
Calibration mode
The deciding factor in obtaining a reliable reading from a wall scanner is his calibration prior to measurement. Through calibration, the device measures the thickness of the wall or surface to be analyzed, the density of the material and records factors such as humidity, temperature and even the accumulation of static electricity that forms when holding the scanner with our hand. In this way, the sensors “take knowledge” of the surface that they must analyze in order to differentiate the objects they detect.
Generally, this calibration is done manually, following a process indicated by the manufacturer in the user manual. However, other manufacturers provide their scanners with the automatic calibration, which translates into two measurable advantages: devices can be used immediately and objects are detected with greater precision and fewer errors. Therefore, a wall scanner with automatic calibration it will be a more than interesting addition to our choice.
False positives”
As we also pointed out in the previous article, one of the biggest problems of the wall scanners are the false positives, that is, the detection of a non-existent object due to unfavorable measurement conditions or, as is more often the case, the fact that an apparatus is being used in an unsuitable material. That is why it is always important to read the instructions and check that the device’s sensors are compatible with the material that we are going to inspect. For example, if many objects are displayed on the screen of the device, the wall may have only several holes. Therefore, a wall scanner Being able to locate hollow bricks can help us figure out what is really behind that wall.
Figure 2-Detection in hollow brick with wall scanner
Indication of the center of the object
The vast majority of wall scanners are provided with a function that locates the edges of beams and other objects. This means that the user must mark the left and right edges of the object with a pencil as they slide the scanner across a surface and manually locate the exact center of the object from those marks. However, there are also wall scanners with special technology that directly indicate the center of object, which can be easier and save a lot of time. If you want to locate wooden beams, for example, to make holes, these must always be made in the center of the beam, therefore a scanner that incorporates the function of indication of the center of the object it will be of great use.
Figure 3-Modes on screen with wall scanner
Detection modes
Almost all the wall scanners They come equipped with various preset detection modes, which the user selects based on the requirements and the manufacturer’s instructions. The simplest models, ie beam detectors, feature beam, metal, and live electrical wire detection modes. As the models progress in complexity and cost, modes are incorporated that contemplate the detection of objects according to the material analyzed. For example, there are modes detection in radiant floors, lightweight partition, concrete Y hollow bricks in order to locate metal pipes, plastic water pipes, live cables, wooden and metal beams, etc. These models also have a universal mode set by default, which is suitable for almost all masonry wall applications, being able to detect plastic objects, metal and electrical cables. If our work is carried out in a variety of settings (for example, in the case of general installers, electricians, decorators, etc.) all these specific detection modes will be an important detail to consider.
Detection and drilling depth
As we can see, today the market has wall scanners capable of unveiling certain objects that exist behind an unknown wall. However, there are not many who can also indicate, the depth to which these objects are hidden that locates the scanner and maximum depth at which drilling is possible. It is clear that the greater the detectable depth, the more benefits the device will offer to a greater number of construction specialists, that is, electricians, carpenters, plumbers, installers of Drywall, decorators, etc.
Although manufacturers report the maximum depth (eg 150mm) that their scanners can reach, we must understand that this is material dependent and not the same for all materials. The wooden beams are those that are detected at the shallowest depth, which varies between 38 and 40 mm depending on the models. Live cables are detected up to a maximum depth of 50 and 60 mm. Finally, metals are those that can be detected at the maximum depth declared by the manufacturer, in some models, regardless of whether they are ferrous or non-ferrous, while in other models ferrous ones are detected at a greater depth than non-ferrous ones.
Figure 4-On-screen indications with wall scanner
Backlit display
The arrival of the wall scanners provided with a screen allowed a great advance in the detection of materials, the identification of the type and thickness of the detected material and, in some models, even the indication of the depth of the object and the maximum allowable drilling depth, providing a simple and friendly interface with the user. Manufacturers that also provide backlit displays add better visibility in any ambient light condition.
