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(11) | EP 0 914 840 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Improved fire protection systems in ventilation installations |
| (57) This invention relates to the improvement of fire protection in aeration-ventilation
systems, where the bulkhead (4) of the aeration and ventilation pipes (2) of the system
installed in a building is characterized by the fact that it is held in the lifted
open position by means of a polyolephinic thermo-shrinking element (1), which lines
the inside of the pipe (2) for a short stretch in the proximity of the bulkhead (4),
which poliolephinic system (1) is capable of maintaining a stable form memory at room
temperature, and in a predetermined temperature range, and is capable of radially
and axially shrinking as the temperature increases and when the temperature reaches
the predetermined values, when it deprives the bulkhead of support and leaves it free
to drop and to seal off the pipe (2). |
Technical field
[0001] Subjects of the present nvention are perfectionings to fire protection systems in areation and ventilation installations,
Background of Art
[0002] It is well known that the aeration-ventilation systems are, in synthetic terms, constituted by a system of ventilation ducts destined to aerate, by admitting air by ventilators, premises, or more generally spaces (for example lifts) displaced into the buildings.
[0003] With the prevailing tendency to build closed and air conditioned volumes, by now largely adopted all over the world, the aeration-ventilation systems have assumed a proportional diffusion. As concerns of the protection from fires, referred to the above mentioned systems, the legislation is extremely different in all the countries of the world; the different sensibility seems connected to the dimension of the accidents occurred.
[0004] It is notorious infact that, in case of fire, the fumes developped, driven by the ventilation ducts, reach the different areas connected, with inauspicius results.
[0005] The tendency of most modern protection systems is to induce closure of the ventilation ducts, automatically when the fumes, caused by fire, would try to pass.
[0006] The system adopted is in many cases, because of the heat connected with the fumes, based on an element sensible, in a selective way, to temperatures.
[0008] A typical example is the one largely used in nothen European countries, where a fire bulkhead, dimensionally projected to interrupt the aeration duct, is kept raised and hung by a metal lock constituted of alloys, melting at the temperatures of the fumes caused by fire.
[0009] When the temperature of the fumes reaches the melting point of the meltable alloys, these ones, melted, let the fireproof bulkhead fall down interrupting the aeration duct and stop circulation and diffusion of fumes in the environments.
[0010] The system described, or similar ones largely adopted, presents some determinant disadvantages such as:
■ the uncertainity of reaction while the system is reaching the foreseen temperatures;
■ the necessity of maintenance, foreseen by the law in force, that would check periodically the system efficiency, in order to guarantee the relevant reliability, determining a relevant increase of the operating costs;
■ furthermore housing containing fireproof bulkheads exposed to the air fluxes, are object of sedimentations and encrustations, which restrict or block free and tempestive falling of the fire bulkhead which has to interrupt the duct;
■ the housing itself, of the fireproof bulkhead exposed to fluxes of ventilation air, is cause of noises and vorticoses moviments, with consequent loss of efficiency.
Disclosure of invention
[0011] Subjects of the present nvention are perfectionings to fire protection systems in areation and ventilation installations, according to which the manufacturing of a product is realized, whose shape is compatible with the aeration duct and housing shape made by poliolefine components, able to keep a stable memory of form at the ambient temperature and in a certain temperature range, able to react, shrinking for example axially and radially, as temperature increases when it reaches pre-determined values; the poliolefine element above mentioned, lines for a short piece the internal walls of the aeration ducts in corrispondence of the fire protection bulkhead, and it is fixed with suitable means, for example to the aeration duct, on the opposite side in respect of the fireproof bulkhead, which in normal conditions, is kept raised by the poliolefine element.
[0012] In case of fire and in any case when reaching determined temperatures, the poliolefine element recovers axially and radially letting the bulkhead free to fall interrupting the continuity of the aeration duct and avoiding the spread of fumes in other areas.
[0013] Another topic of the invention is a poliolefinic compound which is produced by appropriate industrial process. This compound is able to react selectively to heat, shrinking radially and axially, coming back to the initial dimension before being deformed by heat.
Brief Description of the Drawings
[0014] All things summaruly described so far will be better understood by the enclosed drawings:
■ Drawing n° 1 shows an air pipe including its fireproof bulkhead, equipped by the polyolefinic system in a normal work position
■ Drawing n° 2 shows same airpipe after that temperature inside has reached the so called "activating temperature" of polyolefinic system.
Description of a preferred embodiment of the invention
[0015] In this example, chosen to illustrate the present invention, the polyolefinic system (1), made by a polyolefinic compound able to retain memory form, and to be activated by heat, lines the air pipe for a short lenght (2) adjacent to the internal surface.
[0016] The polyolefine system is kept hold in one internal point the air pipe (2), opposite to the bulkhead. In this way, when the inner temperature reaches the activating value (Fig. 2), the polyolefinic system shrinks radially and therefore axially in the opposite direction to the blocked side in order to provide falling down of the air pipe fireproof bulkhead.
[0017] One possible solution to block the polyolefinic system could be the use of a metallic eyelet (3). In this way, and moreover by using a metallic holding system, the polyolefinic system is surely kept hold to the pipe.
[0018] Again, when the polyolefinic system is not activated (1), the bulkhead (4) cannot go down, kept inside by our heatshrinkable device and the airpipe (2) is free. As soon as the duct inner temperature reaches the activating one, the polyolefinic system shrink axially and radially, in order to allow falling down of the fireproof bulkhead blocking the air pipe (2) cross section.
[0019] The polyolefinic system of the present invention is constitued by a polyolephine base and several different charges, by which, the full system can get particular and appropriate features (like flame retardancy and others).
[0022] Co-polymer as acrylate, EVA, EMA, can be equally used as single components or part of compound; anti-oxidant or stabilizing agents are even necessary when designing appropriate compounds, because, due to thermal treatments in process, their features can be considered as fondamental.
[0023] Moreover, as anticipated, it is possible to mix charges as hydrate alumina, able to confer flame resistance, and carbon black, to confer inertia at UVA and electrical conductivity. In order to improve polyolefin heat conductivity, it is necessary to add conductive metallic oxide agents, metallic powerds, etc. It has been noticed that the use of a flexible polyolefine is very effective, due to its high elongation capability, even when cross-linked. Peculiarity of our system is that it has been designed as a system with different speed to thermal inputs, so that elongation capability higher than 30% can be achieved
[0024] The techniques used to confer memory shape are based on use of accelerated electrons or chemical substances, in case of chemical cross-linking, followed by chemical and thermic treatments. Once the above memory has been conferred to the product it will be submitted to different cycles of temperatures process
[0026] The process, in the main phase, is realized by heating the product to the right temperature, however variable for each kind of compound, and acting on it, deforming by pressure, vacuum, mechanical actions, using matrixes, calibers and dies.
[0027] Last is the cooling process, that could be accelerated, until the environmental temperature, which once reached, let the product remain in its stable shape, as already indicated, as long as a thermic event, similar to the one above described, occurs.
[0028] The advantages that arise from the adoption of perfectioning to the fire protection systems in the aeration-ventilation installations as for the present invention, can be resumed in the following points:
■ possibility to adhere to the aeration duct shape, avoiding losses of efficiency and noise;
■ certainity of intervention in a wide thermal range;
■ protecting of the fireproof bulkhead housing with consequent elimination of possible deposits, and oxidations that limitate the free falling of the bulkhead;
■ elimination of corrosion problems affecting the metallic alloys, currently used to block the suspended bulkheads, and consequent elimination of periodic maintenance as provided for the present legislation.
1. Perfectioning to the fire protection systems in the aeration/ventilation installations
in which the fireproof bulkhead (4) designed in the ventilation and aeration conduits
(2) of a building, is characterized by the fact it is kept in the opening lifted position
by a poliolefinic heat shrinkable product (1) which lines, for a short piece, the
conduit (2), close to the fireproof bulkhead; this heatshrinkable device (1) has to
be able to retain a memory of shape, stable at the ambient temperature and in an established
range of temperatures, has to be able to heat shrink radially and axially, at the
increasing of the temperature when it reaches pre-determined values, leaving the fireproof
bulkhead (4), not any longer supported, free to fall to obstruct the conduit (2).
2. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according with the previous claims characterized by the fact the heat shrinkable polyolefinic
product (1) which lines the aeration conduit (2) is fixed to the conduit itself, preferably
by a metal eyelet (3) located at the opposite side of the heat shrinkable device,
in respect to the fireproof bulkhead position; this metal eyelet beeing blocked by
a rivet or a similar device.
3. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according to the previous claims, characterized by the fact the heatshrinkable device
or product is made by a polyolefinic compounds, composed by a polymeric base and various
charges, commonly solid, able to supply to the compound particular characteristics.
4. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according to the previous claims, characterized by the fact the heatshrinkable product
is able to shirnk axially between 5% and 90% compared to the initial dimensions.
5. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according with the previous claims, characterized by the fact the heatshrinkable device/product
is fixed tot he conduit at its extremity, or at any other point which allow the free
shrinking of the other extremity.
6. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according with the previous claims, characterized by the fact the heatshrinkable device/product
shrink at the temperature of 150°C within 5 minuts of time.
7. Perfectioning to the fire protection systems fthe aeration/ventilation installations,
according wuth the previous claims, characterized by the fact the heat shrinkable
product-device shrinks by temperatures between 80°C and 170°C ad by times between
30 seconds and 10 minutes.
8. Perfectioning to the fire protection systems of the aeration/ventilation installation,
according wuth the previous claims , characterized by the fact the heat shrinkable
products-device remains stable, with no variations in its dimensions, when continuosly
exposed at temperatures variable from 60°C to 145°C for 20 days time.
9. Perfectioning to the fire protection systems of the aeration/ventilation installations,
according with the previous claims, characterized by the fact the polymeric bases
of the polyolefinic compounds are low and medium density polyethilenes.
10. Perfectioning to the fire protection system of the aeration/ventilation installations,
according with the previous claims, characterized by the fact the polymeric bases
of the polyolefinic compunds are liner and high density polyethilenes.
11. Perfectioning to the fire protection system of the aeration/ventilation installations,
characterized by the fact copolymers like acrilates, ethilene vynil acetate (EVA),
ethilene metil acrilates and similar are utilized alone or as components of polyolefinic
compounds
12. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact in the stabilyzers and anti-oxidant are compounded as components
in the polyolefinic compounds
13. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact charges as Aluminium hydrate are loaded in the polyolefinic
compounds.
14. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact carbon black is compounded in the polyolefinic compounds.
15. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact conductioning metal oxides and/or metallic powders are compounded
in the polyolefinic compound.
16. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact flexible plyolefinic compounds are used.
17. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact the heat shrinkable part will assume memory of shape because
of the action of accelerated electrons chemical treatments, both followed by thermal
and chemical process.
18. Perfectioning to the fire protection systems of the aeration/ventilation installations,
characterized by the fact after memory assumption, the polyolefine heat shrinkable
product, submitted to the proper temperatures, is deformed by pressure, vacuum, nechanical
actions by using matrixes, moulds and calibrators.
19. Perfectioning to the fire protection systems of the aeration/ventilation installationa,
characterized by the fact, after the thermal processes, the heat shrinkable product
is cooled until reaching the ambient temeprature at wich the product will mantain
its stable form.