Ventilation Systems

Air exchange for production facilities

Client: Marcegaglia
Aim: A group that is a European leader (and among the first in the world) in the production of pipes and steel processing.
Kind of project: Inside a commercial structure, insertion of a system with two distinct functions: forced evacuation of smoke and heat; and daily ventilation.
Description: Installation, in order to guarantee adequate air exchange, of an allweather – Unilab natural ventilation system.

Description of the problem

marce

The Marcegaglia production facilities required adequate air exchange for lane 2, just as had already been created for the space in lane 1. The heat present inside the warehouse stratified spontaneously according to a thermal gradient that could be taken advantage of in order to obtain upward thrust. This effect became even more pronounced during hot months. The solution identified takes advantage of vertical convective motes in the air inside the building in order to stimulate a natural extraction that determines the necessary air exchange with fresh air entering from outside, bypassing the need for a forced extraction system, which would have been expensive to install and run, and still would not have been particularly effective.

Static natural extraction is achieved through allweather openings on the roof realized with Bovema Unilab 1 products, allowing for continuous extraction of the hottest air stratified in the top segment of the warehouse. The supply of fresh air in the lower part of the warehouse is achieved through openings at the base situated along the building’s perimeter (intended as a group of 20 warehouses), in first place the two head openings of lane 2. The average distance of these openings from the volume addressed by the exchange was factored into the company’s calculations through a form factor inferior to the unit itself. Therefore the solution identified is based on natural air movement, which could be taken advantage of thanks to the special design of the static extraction system, which gives it its all-weather characteristics. This systems permits a uniform flow of fresh air, producing laminar flows even in the central part of the warehouse.

The main elements of the system include: no. 11 rooftop, rain-proof natural ventilation elements for a total of roughly 350 m2 (geometric surface), and an average extraction capacity of approximately 600,000 m3/h (full-colored elements in the following image, air is expelled vertically from the page). The volume affected by air exchange: roughly 336 x 45 x 12.5 = 189,000 sqm, corresponding to lane 2 (the element outlined in the following image). The thermal gradient takes on a value of approximately 0.65° C/m, based on yearly averages, developed only vertically, which in turn draws in fresh air horizontally from the outside edges of the volume in question (represented by arrows in the following image).

Advantages of the Unilab solution

Excess heat is extracted, helping lower temperatures during the summer months.
Natural extraction of polluted air takes place without any extra costs (energy).
Natural extraction self-regulates based on temperatures and thermal charges.