RU2331447C1 - System of anti-fire and anti-explosion protection of buildings and structures - Google Patents

Abstract

FIELD: blasting operations.

SUBSTANCE: system of anti-fire and anti-explosion protection of buildings and structures incorporates a metallic layer of outer lining possessing damping qualities to be attached to the object to be protected using a flexible carcass and a bloating layer applied onto the protected object surface so that between the aforesaid lining layer and that of bloating coating an air gap is formed. The gap sizes are selected proceeding from the terms of a complete straightening of deformed outer lining layer by a bloating layer bloated by a heat flow caused by fire.

EFFECT: integrated high-efficiency anti-fire and anti-explosion protection.

2 cl, 2 dwg

Description

The invention relates to the field of protection of structures of buildings and structures from explosion, as well as their protection for a specified period of time from technical damage from damage when exposed to high temperatures.

A large number of solutions are known in the field of protecting structures from high temperatures in case of fires.

Known previously proposed by the applicant method of attenuating the effects of an energy stream in the form of light, heat and convective gas flows on protected objects according to US Pat. RU No. 2284202. The method consists in forming a layered composite fire protection covering the protected object, determining its optimal composition and structure by modeling heat and mass transfer processes in the fireproof structure and the protected object.

In addition, the applicant proposed a collapsible protective structure and method for storing tanks with flammable substances (application RU No. 2004134118, publ. 10.05.2006). A characteristic feature of the method is that in the structural composite fire protection there is a gap between the outer protective and decorative cladding and the heat-resistant heat-insulating layer. And in a fire, this gap is filled with foam coke intumescent coating deposited on the surface of a heat-resistant heat-insulating layer. The outer lining protects the foam coke, which is an ideal high-temperature heat insulator, from burnout and shedding during prolonged fire exposure. Due to the successful combination of the properties of the individual layers of this composition, it is possible to significantly increase its effectiveness.

Explosion protection devices are also known (for example, US Pat. No. 3,996,563 and No. 6,200,664), which are a barrier having a rigid, for example, cellular structure.

However, these data and other well-known solutions do not provide protection against combined impacts such as shock-explosion-fire or explosion-fire on protected objects. Accordingly, they do not intend to use a structure capable of restoring its shape after impact.

At the same time, in the current real threat of terrorist manifestations (for example, explosions) in relation to potentially dangerous buildings and structures such as high-rise buildings and underground traffic intersections, the urgency of the problem of passive fire and explosion protection of load-bearing, enclosing structures and engineering elements systems of these objects.

The technical task underlying the present invention is to provide protection against combined impacts such as "shock-explosion-fire" or "explosion-fire" on the protected objects.

The technical result of the proposed invention is a comprehensive fire protection of objects through the use of a structure capable of restoring its shape after impact (explosion) when activating fire protection mechanisms.

The specified technical result is ensured in the proposed system of fire and explosion protection of objects, in particular, structures of buildings and structures, consisting of a metal layer of the outer cladding having damping properties attached to the protected object using a flexible frame, and from an intumescent coating layer applied to the surface of the protected object in this way that between the aforementioned outer cladding layer and the intumescent coating layer an air gap forms, the dimensions of which are selected from the conditions for the complete straightening of the layer of the outer lining deformed in the event of an explosive action by an intumescent coating, expanded under the action of heat flux during fire exposure.

Preferably, the metal layer of the outer cladding is made of ductile steel.

The proposed system of fire and explosion protection of objects is illustrated by drawings, which show:

on figa-1b is a diagram of a constructive composite fire and explosion protection with a combination of special effects of the type "explosion-fire" under the influence of an explosion,

on figv-2g is a diagram of a constructive composite fire and explosion protection with a combination of special effects of the type of "explosion-fire" under the influence of a fire.

The proposed fire protection system consists of a layer of intumescent coating 2 applied to the protected object 1 and secured by fastening elements 3 of the outer metal layer 5 of the outer lining, between which an air gap 4 is formed.

The operation schemes of the structural composite fire protection under combined special effects of the type of "explosion-fire" is shown in Figure 1-2. In the diagrams it can be seen that at the first stage, under the influence of the shock wave 6 of the explosion, the outer layer 5 of the structural composite fire protection is deformed. The presence of plastically deformable or partially collapsing fire and explosion protection (outer cladding) can reduce the force of the shock of the blast wave on the protected element, due to the dissipation of its mechanical energy. This is the explosion protection effect of the proposed fire and explosion protection system.

In the second stage, under the influence of heat flux 8, the coating 7 swells from the flame. In the third stage, the previously deformed outer layer 5 of the composition straightens under the influence of the pyrolysis gases of the intumescent coating 7, after which it performs a fire-retardant function for a predetermined time. The duration of the construction of this type in the fire protection mode mainly depends on the thickness of the initial layer of intumescent coating.

Thus, when choosing rational methods and means of fire protection of building structures and elements of engineering systems in the new conditions, one should take into account not only the traditional requirements imposed on them [Strakhov V.L., Krugov A.M., Davydkin N.F. Fire protection of building structures, - M.: Information Center "TIMR", 2000, - 433 pp.], But also take into account the peculiarities of their behavior in combined impacts such as "shock-explosion-fire" or "explosion-fire."

With combined impacts such as "shock-explosion-fire" or "explosion-fire" it is possible:

- partial mechanical damage to fire protection during dynamic impacts before the onset of the fire (for example, plastic deformation or collapse of the outer layer of composite fire protection);

- complete mechanical destruction of fire protection during dynamic impacts before the onset of the fire stage on a part of the surface of the protected object;

- large deformations of fire protection in the zones of connection of elements of protected structures located outside the zone of intense exposure to the blast wave, due to deformation of the building frame and (or) the corresponding elements of engineering systems;

- melting or burning out (in the case of materials on an organic basis) of the outer layers of fire protection due to a higher temperature level and the duration of the fire exposure to it in a real fire compared to a standard fire.

Based on the foregoing, it seems appropriate to ensure the structural safety of high-rise buildings and underground structures to use in the proposed fire and explosion protection system of objects, in particular the structures of buildings and structures, discussed above, fundamentally new approaches and solutions of the applicant in the field of fire protection of lining elements and engineering systems of transport tunnels, and also fire hazardous technological equipment of the oil and gas complex.

So, for example, a flexible fire-retardant design in the case under consideration can find application for areas of connection of the elements of the building supporting frame to each other. Those. additional means for protecting flange joints may be provided, made in the form of compensators for linear thermal expansion of the box-shaped structure made of flexible thin-sheet fire-resistant material.

In these cases, the entire structure is able to withstand large deformations during impact (explosive) impacts on a building or structure, while maintaining its operability in a fire that could follow an explosion.

In addition, as shown by the fire tests, flexible fire protection is indispensable in the areas of expansion joints for thermal expansion of ventilation ducts of the smoke exhaust system of tunnels. In these cases, it provides reliable fire protection at relative displacements in the conditions of fire of the ventilation box sections to a distance of 150 mm. Flexible fire protection can perform a similar role in cases where the ventilation box sections are displaced relative to each other, as well as relative to structural elements of a building or structure, under shock or explosive impact on it. In these cases, flexible fire protection should be installed in the areas where ventilators are connected to building structures.

Thus, the system of structural composite fire protection with an air gap between the outer cladding of plastic steel, attached to the protected object using a flexible frame, and an intumescent coating applied to the surface of the object, can fundamentally solve the following problems:

- during an explosive impact on an object due to the damping properties of the cladding, the load on the protected object is reduced (in this case, the fire protection function implements explosion protection);

- during the fire exposure following the explosion, the air cavity under the deformed outer layer is filled with heat-resistant foam coke of the intumescent coating, which is an ideal heat insulator at high temperatures (the fire-retardant function of the system under consideration is effectively implemented);

- the outer metal layer of composite fire protection also protects the foam coke from premature burnout and shedding under the action of elevated temperatures characteristic of a fire in high-rise buildings and underground structures, which makes it possible to use this composition at a high level of the required fire resistance limits.

Claims (2)

1. The system of fire and explosion protection of objects, in particular structures of buildings and structures, consisting of a metal layer of the outer cladding having damping properties attached to the protected object by means of a flexible frame, and from an intumescent coating layer deposited on the surface of the protected object in such a way that between the layer the outer lining and a layer of intumescent coating forms an air gap, the dimensions of which are selected from the condition of complete straightening of the deformed in the case of an explosion th exposure intumescent layer facing the outer coating, expanded under the action of heat flow when unexposed. 2. The system according to claim 1, in which the metal layer of the outer cladding is made of plastic steel.

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