Air Treatment Systems
Following the environmental European regulation the air contaminated with any pollutant must be treated before emission. Two different kind of pollutants contaminating the air in shipyards and marinas can be considered : VOC ( volatile organic compounds) and SOV (volatile solvent compounds). VOC are very small particles (dust) that can be released in the atmosphere during many different works like woodworks, sanding and others while the SOV are small drops of solvent or hazardous fumes that can be released in the atmosphere while painting, welding or while making fiberglass works. In some cases (like painting works) VOC and SOV are released at the same time.
The removal of COV and SOV from air can be done using different filters. Inter alia shipyard solution adopt dust filters (COV) and activated carbon filters (SOV).
DUST FILTERS: made in fiberglass non – woven fabric is able to capture dust particles with very small dimension ( up to 2 µm) and can collect from 1800 to 3000 g/m².(c) (d)
ACTIVATED CARBON FILTERS: Shipyard Solution adopts two different activated carbon filters depending on the use and on the dimension of the system.
FABRIC: made in coconut shell activated carbon fiber attached to a non – woven fabric is able to adsorb between 15% and 35% of solvent depending on the thickness of the fabric. The fabric consist of a minimum of 40% of coco activated carbon material (a)
GRANULAR: made in 100% grain of coconut shell activated carbon is able to adsorb up to 90% of solvent depending on the dimension of the activated carbon beds filters (b)(e)
Another important issue in air treatment system is that any kind of works is strictly forbidden in open air. It means that, following the European regulation, woodworks, welding, sanding, spray painting and also paintbrush is not allowed in open air. Considering this prescription Shipyard Solution has developed a wide range of air treatment that can be used in combination with Shipyard Solution’s shelters. To better understand how to choose the right air treatment system is important to evaluate:
· The inner size of the shelter
· The medium size of the boat/yacht that will enter the shelter.
Let’s imagine , as a mere example, that the inner size of the chosen shelter is 30*8*10m (L*W*H) . The inner cubic meters will be:
And the medium length of the yacht will enter the shelter is 25 m. The average cubic meters of the yacht will be:
25x(8/1,5)x(7/1,3) (L*W*H) = 717 m³
From this simple calculation we understand the free m³ inside the spray booth is
2.400 m³ - 717 m³ = 1683 m³
To get a perfect recycling of the air inside the shelter we need to have at least 50 cycles/h. So we need a system with at least :
1683 m³ x 50 = 84.000 m³/h
The European regulation accept also only 10 or 20 cycles per hour ( depending on different countries) but the quality of the work’s finishing in case of spray paint will be much better as much high is the number of cycles per hour. The power of an air treatment plant is the result of the nominal power of the fan (s) decreased the efficiency’s loss of the plant. Generally the efficiency’s loss of plant can be estimated around 15%. Back to mere example we will choose a nominal power of the fan of 100.000m³/h.
These are not the only values that must be considered to make the engineering of the right air treatment plant because it is also important to consider the air speed inside the shelter, the air speed in the filters, the Kg of activated carbon, the m² of the dust filters and, the most important, the quantity of pollutants produced during the different works.
In fact, the quantity of allowed emission of COV and SOV is fixed ( 3 mg/m³) and is based on the European regulation and the efficiency of the filter is fixed due to the technical data sheet of the filters.
THE AIR TREATMENT PLANT IS NOT ONLY AN OBLIGATION FOR THE ENVIRONMENTAL CONTROL
Shipyard Solution air treatment plants are not only the right solution for the environmental control in shipyards and marinas but can also improve the quality of spray paints because the air will be free of particles that will not be present during drying of the panted surfaces. Especially with Shipyard Solution spray booths model AT003 is possible to obtain the highest quality finishing of boat’s and yacht’s paints thanks to the temperature and humidity automatic control and the complete lack of particles during painting and during drying. Every Shipyard Solution Spray Booth is studied to have the right AIR FLOW to avoid any dust inside the spray booth. With this technology is possible to avoid also orange peel defects.