GB1585937A - Demolition of building - Google Patents

Description

(54) DEMOLITION OF BUILDINGS (71) We, CHEMISCHE FABRIK KALK, GMBH, a company organised and existing under the laws of the Federal Republic of Germany, of Postfach 91 02 10, 5000 Koln 91, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of demolishing buildings i.e. converting buildings to rubble.

One of the problems of our times, which is of ever increasing significance, is that of preventing air and environmental pollution, particular attention being paid to air pollution. Although many efforts are made to reduce the formation of flying dust to a minimum, this problem is far from being sufficiently overcome with the means and measures available. Thus for example when demolishing buildings, the demolition crew mainly use measures which are primarily intended to protect street traffic and passersby from pieces of falling masonry, whereas the dust which is produced in the demolition operation can spread in the air without impediment and pollutes the environment to a quite considerable degree. The same dust pollution occurs when loading and unloading building rubble.

No practicable method has previously been disclosed, whereby the formation of dust when demolishing buildings can be effectively prevented that is to say, the dust can be bound as soon as it is produced, and rendered substantially unable to fly in the air.

It is well known that dust can be p;e- vented from swirling up by dampening the dust with water. However, such measures are 'only suitable where the dust in question is still. Thus, this procedure is employed for example in street cleaning operations and anywhere that large amounts of, dust-like polluting materials are to be eliminated. In this process, an excess of water is required, in relation to the dust to be removed. In particular however the water evaporates at a greater or lesser speed so that in a relatively short time the dust is again'fully'able to float in the air. For these reasons, solutions of hygroscopic salts have then been recommended as dust binding agents.

Thus, published German Patent Application (Offenlegungsschrift) No. 23 55 759 proposes using a solution of hygroscopic salts, instead of pure water, for binding dust on streets and parths. Solutions containing calcium or magnesium chloride are preferably used for this purpose.

As dry dust particles are distinguished by hydrophobic properties and are, therefore difficult to wet both with water and also with salt solutions, it has further been recommended to add a wetting agent'to the water or the salt solutions. Simply spr.~y- ing buildings which are to be demolished, even with hygroscopic salt solutions containing wetting agent, only results in a slight reduction in the amount of dust which can float.

From this there has arisen the problem of binding the dust which is produced when demolishing buildings, effectively and in such a way as to make it non-floating over a niuch longer period of time.

The invention provides a method of demolishing buildings (or parts' of buildings) of masonry, which comprises treating the masonry with an aqueous solution of' a hygroscopic salt, in which solution a nonionogenic wetting agent is also present, and demolishing the masonry after and/or during the treatment.

The aqueous solutions of any salts which, by virtue of their hygroscopic properties, delay or prevent the solution from drying up, are suitable for the treatment of masonry according to the invention. In particular, solutions, of calcium chloride, magnesium chloride, or mixtures of such alkaline earth chlorides, which should be contained in the solutions to be used, in amounts of from 3 to 30% by weight, are suitable for the purposes of the invention.

The presence of a wetting agent in these salt solutions, and the improved wetting of the hydrophobic stone particles, ensure that the masonry being treated is substantially saturated. However, it is possible to use only those wetting agents which do not become ineffective in particular in a more highly concentrated solution of the hygroscopic salts, preferably the alkaline earth chloride solution. Non-ionogenic wetting agents, such as for example alkyl phenol oxethylates have been found particularly suitable for this purpose. Ionogenic wetting agents tend to separate out in concentrated salt solutions. The concentration of wetting agent is preferably from 01 to 05% by weight.

The use of such solutions, in accordance with the invention, can be effected by distributing the solution to a pipe system by means of a pump from a storage container.

The pipes are firstly installed in the top storey of the building which is intended to be demolished. The pipes are closed at the ends and are provided all around, in the last one to three metres of their length, with holes which are from about 1 to 5 mm in diameter. There are from about 1 to 2 holes per 10 cm2. One or two additional pipes can possibly also be provided with holes in the same manner, the solution being sprayed through the holes. These pipes are to be needle-pricked or are to have holes up to 0 5 mm. The hole size selected depends on the pressure produced by the pump. It is also possible for the pipes to be provided with a closely fitting, easily displaceable cover which covers over a part of the holes.

Such a sleeve makes it possible then for the amount and the range of action of the spray and the location at which it has its effect to be varied.

The outside walls of a building should be soaked from the inside, as the outside walls are in most cases weather-resistant and thus allow the salt solution only little chance of penetrating into the walls. It is advantageous for the window frames to be removed and a respective soaking pipe to be laid on to the exposed masonry. The inside walls' and floors are preferably sprayed or sprinkled with the solution with the spraying pipes, until the masonry no longer absorbs any moisture. The soaking operation is begun at the top storey, and then the storey below is treated subsequently, until all the masonry is thoroughly soaked.To improve distribution of the salt solution in the masonry, and to make- the salt solution distribution more even; it is appropriate to allow an action time of at least 24 hours between the end of the soaking operation and the beginning of the demolition operation.

The process according to the invention permits the demolition of buildings or other structures to be performed, with a considerably smaller amount of dust being produce. As the rubble is kept permanently moist by the solutions to be used in accordance with the invention, the dust binding action is maintained even when the rubble is loaded, when it is transported, and when it is unloaded at the dump area. In individual cases, for example when dealing with rubble materials which provide large amounts of dust, it may be advantageous for the rubble to be treated with the said solution during the demolition operation and once more to be treated on its surface before being loaded, in which case solutions with a lower concentration of alkaline earth chlorides are generally sufficient.

A further advantage is that the parts of the rubble which are treated in accordance with the invention and which in themselves are liable to catch fire, for example beams, stairs, floorboards and the like, are protected from fire by the treatment of the invention, which is of significance in particular as regards storage at the dump area.

An important advantage of the process according to the invention is also that it can be performed even when there is frost, as the freezing point of the solutions to be used lies far below the freezing point of water, depending on the particular concentration of the solution. This therefore simultaneously prevents the rubble from freezing together and facilitates its being transported away.

Example A four-storey dwelling with a floor area of 140 m2 is to be demolished. To prepare for demolition, 15 m3 of a calcium chloride solution which contains 30% by weight of CaCl2 and 02% by weight of a non-ionogenic wetting agent is prepared in a storage container. This solution is pumped by means of a motor-driven pump by way of a distributor into ten rubber pipes, each of which 50 m in length and which are provided with holes at their closed end as n- dicated above. The pipes are first laid in the attic. After the attic has been sufficiently soaked, the pump operation is stopped and the pipes are laid in the third storey, and so on, until the entire masonry of the building has been treated. 5 m3 of solution is required for the- attic, 4 m3 is required for the third storey, 3 m3 is required for the second storey, 2 m3 is' required for the ground floor, and l m3 is required for the cellar.

Demolition of the building was begun, 36 hours after the soaking operation had been concluded. The demolition operations took place, with a negligible amount of dust being formed. Loading the building rubble and tipping it at the dump area also caused no dust to be formed.

A mixture of various ethoxylated alkyl phenols is used as the non-ionic wetting agent. The individual components contain one or more alkyl groups with 1 to 5 Catoms and 3 to 9 ethylene oxide groups. A corresponding commercial product is "Marlophen X".

WHAT WE CLAIM IS:- 1. A method of demolishing buildings (or parts of buildings) of masonry, which comprises treating the masonry with an aqueous solution of a hygroscopic salt, in which solution a non-ionogenic wetting agent is also present, and demolishing the masonry after and/or during the treatment.

2. A method according to claim 1 wherein the hygroscopic salt used is calcium chloride, magnesium chloride or a mixture thereof.

3. A method according to claim 1 or 2 wherein the solution contains from 3 to 30% by weight of the hygroscopic salt.

4. A method according to any one of claims 1 to 3 wherein the solution contains from 0 1 to 05% by weight of non-ionogenic wetting agent.

5. A method according to any one of claims 1 to 4 wherein the solution is sprayed on to outside walls, inside walls and floors by way of perforated pipes which are laid in each storey of the building, and the masonry is treated storey by storey from the top in a downward direction.

6. A method according to claim 1 substantially as described in the Example.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. concluded. The demolition operations took place, with a negligible amount of dust being formed. Loading the building rubble and tipping it at the dump area also caused no dust to be formed. A mixture of various ethoxylated alkyl phenols is used as the non-ionic wetting agent. The individual components contain one or more alkyl groups with 1 to 5 Catoms and 3 to 9 ethylene oxide groups. A corresponding commercial product is "Marlophen X". WHAT WE CLAIM IS:-

1. A method of demolishing buildings (or parts of buildings) of masonry, which comprises treating the masonry with an aqueous solution of a hygroscopic salt, in which solution a non-ionogenic wetting agent is also present, and demolishing the masonry after and/or during the treatment.

2. A method according to claim 1 wherein the hygroscopic salt used is calcium chloride, magnesium chloride or a mixture thereof.

3. A method according to claim 1 or 2 wherein the solution contains from 3 to 30% by weight of the hygroscopic salt.

4. A method according to any one of claims 1 to 3 wherein the solution contains from 0 1 to 05% by weight of non-ionogenic wetting agent.

5. A method according to any one of claims 1 to 4 wherein the solution is sprayed on to outside walls, inside walls and floors by way of perforated pipes which are laid in each storey of the building, and the masonry is treated storey by storey from the top in a downward direction.

6. A method according to claim 1 substantially as described in the Example.