Pasi
it
Measuring instruments, geophysical instruments
pasi

Monitoring

WIRELESS DATA ACQUISITION SYSTEMS

For all cases where continuous monitoring is required, it is necessary to use a digital data acquisition system based on the combination of transducers and control units for data acquisition and storage. Data acquisition is the starting point for understanding, measuring, monitoring and managing the mechanism of each phenomenon or process. With the aid of one or more sensors, the information, converted into electrical pulses, is transmitted to an instrument which conditions, amplifies, measures, processes, displays and stores the signals themselves. PASI is able to offer a full range of electronic control units for geotechnical monitoring, environmental monitoring and microclimatic monitoring, managing analogue and digital measurements from one or more external transducers. The wireless WINECAP control units are particularly versatile and easy to install and can be used in a wide range of fields: - structures and buildings - groundwater - meteorological parameters (climate and microclimate) - inclinometric measurements - geotechnical parameters

WATER QUALITY MONITORING

Monitoring the main physical and chemical parameters is critical in order to keep water quality under control, regardless of what it is used for: water analysis is, in fact, essential in many areas of environmental monitoring, ranging from control of the sources and mineral water to aquaculture, fish farming and monitoring industrial discharges, wastewater etc. Geotechnical monitoring, especially for controlling dams, landslides, watercourses and reservoirs, also involves continuous monitoring of changes in piezometric level, which can be decisive in preventing hydrogeological instability which is now unfortunately a frequent occurrence. Another chapter of groundwater monitoring involves well flow tests, essential in order to check the efficiency of the pumping system: also in this case a water level sensor which stores data during the test is an important instrument for checking and optimising production.

Water monitoring requirements are mainly divided into two categories: continuous monitoring (for which it is necessary to store the data measured automatically at predetermined intervals by a fixed probe equipped with a data acquisition unit or "data logger") and time–to–time monitoring (where the operator goes periodically to take the measurements from samples taken at the site, using portable instruments).

MONITORING OF CRACKS ON STRUCTURES AND BUILDINGS

Crack meters are the most simple and immediate instruments used to check damage to buildings or structures. Available in different models (for walls, corners, floors etc.), they are all made up of two overlapping plates. The upper one is transparent and has a grid engraved on it, while the lower one is graduated in millimetres both horizontally and vertically, with the zero located at the intersection of the median lines. The crack meter is positioned so that it straddles the crack, with the zeros on the grids coinciding. The direction and magnitude of the mutual displacement of the parts (in millimetres) are read directly on the graduated plate and can then be observed and monitored over time. If measurement accuracy superior to millimetric accuracy is required, devices (removable crack-meters) must be used that can monitor the evolution of the distance between two or more references linked to the structure (bar or disk datum point) by taking measurements using an analogue or digital comparator. It then becomes possible to achieve accuracy of a hundredth or a thousandth of a millimetre, which allows the user to evaluate the trend of developments in the crack pattern in question (accelerated, delayed, steady, stable progression). In support of these instruments is the MOSES software, able to handle the data acquired on site, collecting it immediately in the test reports accompanied by the most appropriate photographic documentation and graphs.

VIBRATION MONITORING

Environmental monitoring also extends to issues related to site safety. Special regulations ?? refer specifically to noise and vibration due to construction activities and the working environment in general, where structures and individuals may be subject to stress that is sometimes unacceptable or difficult to put up with over time. Increased sensitivity to these issues is reflected in increased attention from workers and citizens in those situations that can easily trigger proven discomfort and long, tedious litigation. In accordance with the DIN 4150-3 standard (Vibration in Buildings, part 3: Effects on structures, 1999), UNI 9916 (Criteria for the measurement of vibrations and the assessment of their effects on buildings, 2004) and UNI 9614 (Vibration measurement in buildings and annoyance evaluation, 1990), blasting activities can be designed, used and monitored so that the vibrations produced in homes nearby are under the threshold at which damage can be caused to buildings and disturbance to residents. To document compliance with the conditions relating to safety and tolerability established by the law, it is advisable to monitor the explosions using one or more vibration monitors, appropriately positioned within the site. Similarly, the vibrations caused by construction activities in urban areas can also create a disturbance for people or even cause or aggravate damage to existing buildings. In this case the vibration monitor can be suitably positioned by the structure to be monitored to check whether the vibrations caused exceed the threshold indicated by the legislation.

NOISE IN THE WORKING ENVIRONMENT

Noise in the working environment has become one of the most important issues related to hygiene in the workplace. The continuous mechanisation of production with the introduction of continuous technological processes has led to the proliferation of noise sources and an increase in the percentage of workers exposed to this risk factor. Noise as the transmission of sounds is a vibratory phenomenon. The most important parameters for measuring the sound wave are the amplitude (representing the value assumed by the pressure) and the frequency (number of oscillations performed by the vibration in one second). The sound is measured in decibels as regards the sound pressure and in hertz and as regards the frequency. The exposure time and the sound pressure are key factors in defining the biological effect of the noise itself. Given the complexity of the biological effect of the noise phenomenon, other parameters may influence its effect, such as the distribution of the frequencies or the individual characteristics of individuals. The instruments with noise can be monitored are called noise meters. These are divided into Class 1 noise meters (suitable for certification) and Class 2 noise meters (normally suitable for internal monitoring). Pocket-sized personal dosimeters that can be attached directly to the clothing of the worker at risk of exposure have recently been introduced. Where noise exposure exceeds 80 decibels, the employer must provide workers with hearing protection devices.

VIBRATIONS ON THE HUMAN BODY

The repetitive oscillatory motion of a body over time (vibration) can be transmitted to humans by contact. The risk from vibration can occur in a variety of circumstances such as driving vehicles, using industrial machinery, using tools powered by electricity or compressed air with striking movements (pneumatic hammers, milling cutters, drills, rock hammers).The obligation to assess the risk and implement the appropriate preventive, protective and health surveillance measures, also applies to exposure to vibrations in the workplace. Vibrations are normally classified according to the type of energy transmission: localised, generally through the hand, and generalised, through the surface in contact with the operator´s body, in both a standing and sitting position. The first are associated with a series of symptoms commonly referred to as ¨Hand-arm vibration syndrome¨. The effects of vibrations on the whole body, on the other hand, can involve various internal organs and systems (gastrointestinal, urinary and genital, vertebral column, visual system, neuropsychological system). Vibrations involving the whole body (¨whole body vibrations¨), on the other hand, are linked to various sources, such as transportation, self-propelled machines, stationary systems.