JP4003909B2 - Electromagnetic shield type fixed structure on free access floor - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to an electromagnetic shield fixing structure of a raised floor, to an electromagnetic shield fixing structure particularly suitable for a reliable fixation of the raised floor.
[0002]
[Prior art]
In office buildings, tenant buildings, etc., there is an increasing demand for electromagnetic shields provided in units of floors or rooms for the purpose of preventing electromagnetic interference of electronic devices installed in the buildings. Electromagnetic shield floors and rooms are electrically conductive members such as galvanized iron plates and conductive non-woven fabrics, or their composite members (hereinafter referred to as electromagnetic shield materials) that can obtain the required shielding effect on the entire wall surface including the floor and ceiling surfaces. ) With no gaps.
[0003]
On the other hand, when floor slabs such as office buildings are formed by joining precast concrete slabs (hereinafter referred to as PC slabs), half PC slabs, etc., it is possible to prevent leaking downstairs due to water leaks on the upper floors. As a purpose, waterproof construction is performed on the floor slab. In general waterproof construction, a waterproof layer made of asphalt or the like is provided on a slab.
[0004]
Conventionally, an electromagnetic shield for a floor slab provided with a waterproof layer is constructed by laying an electromagnetic shield material 9 on the surface of the waterproof layer 6 without a gap as shown in FIG. The construction procedure for providing the layer of the electromagnetic shielding material 9 on the waterproof layer 6 will be briefly described with reference to the same drawing. First, the waterproof layer 6 made of asphalt or the like is applied to the surface of the slab 2 formed by joining the PC plate 1. . The asphalt waterproof layer 6 adheres firmly to the slab 2 with a strong adhesive force. After the waterproof layer 6 is solidified, the electromagnetic shielding material 9 is spread over the waterproof layer 6 without any gaps. The electromagnetic shielding material 9 is fixed to the waterproof layer 6 with an adhesive 8 so as not to break the waterproof layer 6.
[0005]
[Problems to be solved by the invention]
In an office building or the like, as shown in FIG. 5, a free access floor (hereinafter, referred to as “floating space”) that is floated away from the floor slab 2 is provided below the floor slab 2 in order to provide a wiring space 10 suitable for storing computer and communication equipment wiring and connection equipment. Sometimes called OA floor.) 11 construction is increasing. An example of the construction method of the OA floor 11 is to support the OA floor 11 separated from the floor slab 2 by the upper end of the column 12 having the lower end fixed on the floor slab 2. In the electromagnetic shield floor or the like of FIG. 4 described above, the lower end of the OA floor column 12 is fixed on the layer of the electromagnetic shield material 9 constructed on the surface of the floor slab 2. The OA floor support 12 needs to be fixed to the floor slab 2 or the layer of the electromagnetic shielding material 9 with a strength according to a condition such as not moving even when a predetermined horizontal force M is applied.
[0006]
However, when the layer of the electromagnetic shielding material 9 is provided on the surface of the waterproof layer 6 on the floor slab 2, the connection between the floor slab 2 and the waterproof layer 6 is strong, but the floor slab 2 and the OA floor strut There is a problem that it is difficult to secure the fixed strength with 12. As shown in FIG. 5, the relatively thin electromagnetic shield material 9 (generally 1 mm or less) cannot be fixed to the floor surface with an anchor material such as a nail from the viewpoint of protection of the waterproof layer 6, and is an adhesive. It is fixed to the waterproof layer 6 by 8 or the like. At this time, due to unevenness of the surface of the waterproof layer 6, that is, unevenness or a step at the joint portion, the entire surface of the electromagnetic shield material 9 and the waterproof layer 6 cannot be bonded, and strong bonding cannot be expected. Since the OA floor column 12 is fixed on the electromagnetic shield material 9 with an adhesive 8 or the like, and this portion cannot be fixed with an anchor, it is difficult to secure the fixing strength between the floor slab 2 and the OA floor column 12. This is because the thin electromagnetic shielding material 9 is sandwiched between the waterproof layer 6 and the OA floor column 12 although the OA floor column 12 should be directly bonded to the waterproof layer 6. In particular, when the electromagnetic shielding material 9 is a shield nonwoven fabric, almost no fixed strength can be expected.
[0007]
It is an object of the present invention, in order to ensure the fixing of OA floor, it is to provide an electromagnetic shield fixing structure of the free access floor using the electromagnetic shielding waterproof layer having both waterproof ability and electromagnetic shielding ability.
[0008]
[Means for Solving the Problems]
Referring to the embodiment of FIG. 1, the electromagnetic shield type fixing structure of the free access floor according to the present invention is a molten asphalt or urethane waterproof material in the fixing structure of the free access floor 11 floating from the concrete floor slab 2. An electromagnetic shielding waterproof layer in which a conductive powder having a particle size of 5 to 30 μm which is less than 1/3 weight ratio of the total amount and sufficient for the expression of electromagnetic shielding ability is homogeneously mixed and fixed to the top surface of the slab 2 7 and a floor column 12 having a lower end bonded to the waterproof layer 7 with a predetermined strength and an upper end supporting the free access floor 11 .
[0009]
The waterproof material used in the present invention needs to have a waterproof property that does not allow permeation of water and an adhering capability that adheres to a concrete floor slab. The waterproof capability is indispensable for the waterproof function of the electromagnetic shield type waterproof floor using conductive powder, and the fixing capability is indispensable for securing the OA floor. An asphalt-based or urethane-based waterproof material has both this waterproof capability and fixing capability.
[0010]
The reason why the conductive powder is mixed into the waterproof material is to provide electromagnetic shielding ability. Although the details of the mechanism by which mixing of the conductive powder into the waterproof material develops the electromagnetic shielding ability is not necessarily clear, it is assumed that the waterproof material has a finite impedance due to the mixing. The reason why the particle size of the conductive powder is 30 μm or less is that when the particle size exceeds 30 μm, sufficient electromagnetic shielding ability and mixing uniformity cannot be obtained. The amount of conductive powder mixed is set to 1/3 weight ratio or less of the total amount. When the mixed amount is 1/3 weight ratio or more of the total amount, the workability deteriorates, the cost increases, and the waterproof performance decreases. This is because a problem occurs and the electromagnetic shielding performance reaches its peak and does not improve so much. If the particle size is too small or the conductive powder is mixed in too much, the waterproofing ability and the concrete fixing ability of the waterproof material are impaired.
[0011]
Preferred examples of the conductive powder are nickel, copper, aluminum or carbon powder, but the present invention is not limited to these examples.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The type of waterproof material used in the present invention, the type and particle size of conductive powder, and the mixing ratio thereof can be determined by experiment.
[0013]
[Experimental example]
Nickel powder with a particle size of 5 to 30 μm as conductive powder is mixed in the molten asphalt waterproof material at a ratio of 1/4 (nickel amount / total amount) to the total amount, and the materials are mixed homogeneously by stirring. It was. This mixing amount can be appropriately selected according to the required electromagnetic shielding performance in the required frequency band.
[0014]
A 3 mm thick electromagnetic shielding waterproof layer test piece 7t (see FIG. 3) was prepared from the above asphalt waterproof material mixed with nickel powder.
[0015]
Further, as shown in FIG. 3, an anechoic chamber 16 having a radio attenuation of 100 dB or more between the inside and outside is formed by using a double structure surrounding wall made of two metal plates 15, and a test piece mounting window 17 of the dark chamber 16 is formed. The electromagnetic shielding waterproof layer test piece 7t was attached to the fixing device 14 to test the electromagnetic shielding effect by the electromagnetic shielding waterproof layer 7. The test radio wave transmitter 18 sends a radio wave of 50 to 3050 MHz band toward the test piece 7 t of the electromagnetic shielding waterproof layer, and transmits it to the anechoic chamber 16 through the test piece 7 t. The reception level was measured with the test radio wave receiver 19. From the comparison between the reception level measurement value of the test radio wave with the electromagnetic shielding waterproof layer test piece 7t removed from the mounting window 17 and the reception level measurement value of the test radio wave with the test piece 7t attached, the The electromagnetic shielding effect was measured by calculating the radio wave attenuation of the test piece 7t.
[0016]
In this experimental example, it was confirmed that a radio attenuation of 40 dB or more was obtained in the frequency band of 50 to 3050 MHz. Further, the present inventor has confirmed that there is no problem in the fixing ability of the test piece 7t. That is, the same electromagnetic shielding waterproof layer as that of the test piece 7t was applied on a concrete flat plate, and the struts on the OA floor were bonded and pushed down to carry out the test. As a result, it was confirmed that the electromagnetic shielding waterproof layer has sufficient adhesive strength equivalent to that of a general waterproof layer in which conductive particles are not mixed, that is, fixing ability.
[0017]
Therefore, conductive powder such as nickel powder having a particle diameter of 5 to 30 μm is mixed into the top surface of the concrete floor slab 2 shown in the experimental example, for example, in an asphalt waterproof material at a ratio of 1/3 weight ratio of the total amount. By using one, the electromagnetic shielding waterproof layer 7 having both waterproof ability and electromagnetic shielding ability can be fixed. Since the electromagnetic shielding waterproof layer 7 is fixed to the floor slab 2, the OA floor 11 can be securely fixed by fixing the support 12 of the OA floor 11 to the electromagnetic shielding waterproof layer 7.
[0018]
Thus, the provision of “an electromagnetic shield type fixing structure of a free access floor using an electromagnetic shielding waterproof layer having both waterproof ability and electromagnetic shielding ability in order to ensure the fixation of the OA floor”, which is an object of the present invention, can be achieved. .
[0019]
【Example】
Referring to FIG. 2, if the lower end portion of the wall shield layer 9 w in the surrounding wall 3 surrounding the floor slab 2 and the electromagnetic shielding waterproof layer 7 on the floor slab 2 are electrically connected by the peripheral connection member 5. The floor slab 2 can be provided with an electromagnetic shield connected to the electromagnetic shield of the surrounding wall 3. When the upper space of the floor slab 2 is surrounded by the surrounding wall 3 as shown in FIG. 2 and a ceiling (not shown) with an electromagnetic shield connected thereto, the space can be electromagnetically shielded. . In the figure, reference numeral 13 denotes a wall decorative material.
[0020]
The present invention also selects the type, particle size, and amount of conductive powder to be mixed in the waterproof material to form the electromagnetic shielding waterproof layer 7 according to the frequency band of the radio wave to be shielded and the required attenuation. Can do. If the frequency-radiation attenuation characteristics of the electromagnetic shield are measured and recorded in advance for the type, particle size, and mixing amount of the conductive powder used in combination with various waterproof materials, within a certain limit, the required An optimum electromagnetic shield corresponding to the frequency band and the required attenuation can be formed by selecting the type, particle size, and mixing amount of the conductive powder.
[0021]
【The invention's effect】
As described above, the electromagnetic shield type fixing structure of the free access floor according to the present invention uses the electromagnetic shielding waterproof layer having both the adhering ability to the concrete floor slab and the electromagnetic shielding ability, and has the following remarkable effects. .
[0022]
(A) Since a single-function electromagnetic shield layer is not used, the installation process of such an electromagnetic shield layer can be omitted, and the cost and the construction period can be reduced.
(B) The OA floor can be fixed securely and stably.
(C) When asphalt is used as a waterproofing material, the asphalt itself has electromagnetic shielding ability, so there are few damages and performance deterioration factors at each stage of construction, and reliable electromagnetic shielding performance can be ensured at the time of completion. In addition, the surface state of the electromagnetic shield layer can be visually confirmed even after completion.
(D) Since the floor finish surface can be an electromagnetic shield layer, connection to the electromagnetic shield layer on the surrounding wall surface surrounding the floor is easy.
(E) Applicable to roof waterproof floors and other waterproof floors.
(F) An optimum electromagnetic shield floor can be formed by selecting an appropriate waterproof material and conductive powder for the frequency band of the radio wave to be shielded and the required radio wave attenuation.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an embodiment of the present invention.
FIG. 2 is an explanatory diagram of a method of connecting an electromagnetic shield type waterproof floor using conductive powder and a surrounding wall body.
FIG. 3 is an explanatory diagram of a method for measuring an electromagnetic shielding effect.
FIG. 4 is an explanatory diagram of a conventional electromagnetic shield type waterproof floor.
FIG. 5 is an explanatory diagram of a conventional method for installing a free access floor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Precast concrete plate 2 ... Floor slab 3 ... Perimeter wall body 4 ... Electromagnetic shield type waterproof floor 5 ... Peripheral connection member 6 ... Waterproof layer 7 ... Electromagnetic shield waterproof layer 8 ... Adhesive 9 ... Electromagnetic shield material
10 ... Wiring space 11 ... OA floor
12 ... post 13 ... wall decoration
14 ... Fixing device 15 ... Metal plate
16 ... Anechoic chamber 17 ... Mounting window
18 ... Test radio transmitter 19 ... Test radio receiver

Claims (4)

In a fixed structure of a free access floor floating from a concrete floor slab, a particle size of 5 to 30 μm that is less than 1/3 weight ratio of the total amount of melted asphalt or urethane waterproof material and sufficient for the expression of electromagnetic shielding ability An electromagnetic shielding waterproof layer in which the conductive powder is uniformly mixed and fixed to the top surface of the slab , and a floor having a lower end bonded to the waterproof layer with a predetermined strength and an upper end supporting the free access floor Electromagnetic shield type fixed structure of free access floor with support . In fixing structure according to claim 1, wherein the conductive powder of nickel, copper, aluminum or raised floor of the electromagnetic shield fixing structure comprising a carbon powder. The fixing structure according to claim 1 or 2, wherein the electromagnetic shielding waterproof layer has a thickness of 1 to 4 mm and a free access floor electromagnetic shielding type fixing structure . The peripheral connection member which electrically connects the lower end part of the wall surface electromagnetic shielding layer of the surrounding wall surrounding the said floor slab, and the electromagnetic shielding waterproof layer on the said floor slab in the fixed structure in any one of Claim 1 to 3. An electromagnetic shield type fixing structure for the free access floor .

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