Summer finally arrived and, with its consequent climate warming, sudden and strong phenomenon appears, representing our farmers the worst nightmare: storms and hailing caused by the thermal shock of summer days are keeping everybody awake overnight since they risk losing a whole season work in ten minutes.
The only possible solution, of which most of persons is already aware since a while, is represented by hail coverings that, even if they could not stem completely the phenomenon, it can anyway reduce sensible its consequences.
This covering, nowadays the keystone of each professional of the orchard, become everyday more important to protect our crops not only from hail, but also from many other natural situations that affect different part of the world, such as insects (Asian stink bugs over all), birds and sunburn, just to mention some. It is exactly this “multi-functionality” of the anti-hail system that puts it as the crucial point of each plan for agricultural investment, with our expectation for a good turnover of the investment laid on solid and concrete basis.
Unfortunately, as we assist many times when something actually works, recently a lot of persons improvised experts of anti-hail system. And we used the word “system” not coincidentally, because a hail covering is not a set of items cobbled together yet a complex machine that, exactly like the one we use every day, is made of several different articles that together build up a working instrument. And exactly for this reason, the system has to be studied as a whole since only having goods piles might not be sufficient to grant system solidity when undergoing solicitation of the wind.
That’s it, the wind. Wind is the bad guy in this story. It is usually not considered when speaking about systems, just a supporting actor during the show that is on stage during a storm. Attention is all focused on hail stones, its weight, its quantity, even the duration of the storm, as it was the only element that is actually soliciting the system. But it is the wind our first and most important enemy, because under its constant pression and depression the net, our system key element, will move as it had its own life, trying to bring with it the longitudinal wire and the transversal cable, that will in turn try to extract the anchorages from the ground and the caps from the piles, compromising system tension and therefore its stability.
From this point of view, piles appear no longer to be the crucial part of the system, even if at the same time we should not underestimate the need of our structure for standing and sustaining our most precious good, the fruit. Of course, the curtain goes up on the storm always in the moment of biggest “weakness” of our system, summertime (even if this is less and less true, as hailstorms at beginning of May in Treviso area has shown us), when our structure is bearing also the load of fruit, that represent another key element of the equation that defines the needs of our machine.
A hail covering is then a complex system, that needs to count loads of wind strength, fruit and hail weight, to assure the return of our investment. These three aspects have been carefully studied with our technicians and reflect on the choices that we daily have to make to build our systems, but that we often see as underestimated when we are called, like doctors that visits a sick patient, to check systems that are some years old, built cheaply and that shows symptoms of a disease that might bring to an early death.
To evaluate system efficiency then, we have to start from the basis, the supporting elements. “Valente doctors” are able to identify a sick post at glance. A good quality concrete can be recognized by its grey nuance, evidently derived from cement contained in it. Cement is darker when is Portland 525 (with a percentage of Clinker in it up to 80%) like Valente one, while it fades in cheaper varieties. An excessively smooth surface then, that at first sight might be synonym of perfection, is more often clue of a high percentage of water in concrete mixture, water that will evaporate during ripening stages and resulting with a less elastic post (of course, not everybody can count on precision instruments and of a thirty-meters-high mixing tower that grants an homogenous mixture, like it happens in Valente).
After the physical exam of the pile, the doctor will check system geometry and more precisely post squaring. Without prejudice to the sacred rule “everyone is free to do whatever he wants at his own home”, if you ask to a Valente doctor, he will recommend not to overpass five meters distance between rows and not to space piles more than ten meters along it and, finally, that if system is higher than five meters above the ground you are more likely to be building a house rather than a hail system. It is true that along our long history we have always projected tailor-made solutions with our clients, discussing on the different options that we can use to bypass our pre-set parameters, but if there is no basic rules we are again placing some pieces together rather than actually building a system. And, always about sizing, it is good to know that a system should not be longer than four-hundred system (assuming that somebody would really like to harvest four-hundred-meters apple row without the possibility of exiting from it) and no more than two-hundred and fifty meters wide. This to grant the maximum strength and efficiency required by these cases.
After “visiting” piles and system dimensional aspects, he will move on to anchorages examinations, elements that are underground and hidden to sight but that have to properly do their job, or you bet you will sooner or later to pay the consequences. The doctor will extract a measuring tape from his white coat pocket and will place it next to the pile, then reaching the anchorage. There is a minimum distance between pile and anchorage, did you know it? Otherwise anchorage become a piece of furniture rather than a structural element of the system. Our calculations have defined in two meters the minimal distance between the post and the anchorage in a hail covering, even if also this cannot be a given-for-granted truth.
For a soil that offers a not-sufficient resistance (meaning with a sigma lower than 1kg per square meter) is it is better to evaluate the best solution a little longer, not to regret it later. Also anchorages, like piles, talk to our specialist in an easy yet effective way, starting from the assumption that anchorages have to stay underground, obvious truth but not always granted. When you see the rod coming out (the rod, not only the eyelet) you have usually two options: or you were not able to bury it enough (meaning that soil was not as you expected, so anchorage choice was not meditated enough in the beginning) or (and definitely far worst) they are enduring anchor-cable effort following then out of the ground, usually symptom that the plate has separated from the rod. This is really a bad signal, like pain of your left arm might indicate an incoming heart-attack. Our doctor will for sure recommend a shocking therapy for this problem: an extraction test to verify the resistance and, if failed, a therapy base on concrete injections to grant the anchorage to remain where it is and not becoming a weak point of the system.
Obviously over the structure we have a covering, the most expensive and delicate part, to which we will dedicate a special attention on next newsletter, focused on the several fictional works we have seen along the years and that someone calls systems.
Did you read something that makes you doubt of your system stability? Do you need a good doctor consultation? Valente technicians are always at disposal of whom need their advice and help in realizing new systems or in fixing some old guy with chronical illness. Do not hesitate to contact us.