JPH0893076A - Fire-resistant covering laminate structure of steel for external use - Google Patents

Abstract

PURPOSE: To maintain the intended fireproof performance for a long period of time by laminating a lath wire meshing, fireproof covering material layer, and waterproof layer one over another on the surface of a steel column/beam, wherein the covering material layer is of wet type and its draftiness in the dried condition lies within a specific range. CONSTITUTION: A lath wire meshing (c), wet type fireproof covering layer (d) having a draftiness in the dried condition ranging 10-10000 (l/m<2> min.100 mmHg.20mm), and a waterproof layer (f) are laminated one over another on the surface of a steel column/beam (a). The steel member (a) is of a structural steel material to be used in an ordinary structure. The lath wire meshing (c) is a plasterer motrar underlay material the most suitable for a fire proof architecture. A favorable example of the wet type fireproof covering material (d) should have a draftiness ranging as mentioned above and contain chiefly cement, aluminum hydroxide, lightweight aggregate, and fillar. It is also specified so that the tensile strength of the waterproof layer (f) is over 50N/cm<2> , rate of elongation of the coating film is over 50%, and the water permeability is below 0.5ml/24h (all traits conditioned at 20 deg.C in standard condition).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a fireproof coating laminated structure capable of maintaining desired fireproof performance for a long time in a fireproof coating such as a steel frame exposed to the outside of a building.

[0002]

2. Description of the Related Art Conventionally, there are cases where it is legally obligatory to apply a fireproof coating material to buildings and structures such as steel frames. This is to prevent the strength of the steel frame that supports the weight of buildings and structures from decreasing in a high temperature state due to a fire, to prevent buckling in extreme cases, and to maintain the minimum structure. On the other hand, recently, it has become possible to find a structure in which a steel frame, which has been originally designed and has originally achieved the purpose of maintaining the structure inside the structure of the building, is exposed outside the structure, particularly outside. Further, due to the heightening of buildings and the increase in intelligence, steel frames for installing machines, steel structures for heliports, etc. are often provided on the rooftop. In such outdoor fire-resistant coating of steel frames, for example, a lath mortar trowel coating method is often used. This lath mortar trowel coating method is a method in which a lath wire net is used as the base, and plaster is used to apply mortar and plaster. It has the feature that it can be applied to the base material of any shape, and it has a beautiful finish without any joints. In addition to this, a method of enclosing with a metal panel such as aluminum after spraying rock wool, or a method of attaching a water repellent calcium silicate plate to the fireproof coating of pipe racks related to plants that do not require much cosmetic properties Etc. are also used. Rockwool spraying is called dry rockwool or semi-dry rockwool, and is a mixture of cement and a mixture of rockwool with some asbestos sprayed onto the steel surface from a nozzle. At this time, the mixed water atomized by the compressed air sent by the pump is simultaneously sprayed from around the nozzle and sprayed on the construction surface while mixing so as to wrap the constituent materials. This construction method is inexpensive, and equipment such as a spraying machine is lightweight and easy to handle, so there are many construction results. The construction method using a molded plate such as a calcium silicate plate is
This is a method in which a molded plate produced in advance in a factory is temporarily fixed to steel beams and columns with an adhesive, and then attached by using nails and braces. In addition to these fireproof coating methods, construction methods using wet fireproof coating materials have also been tried. For example, an inorganic binder such as cement, an inorganic fibrous substance such as rock wool, asbestos and glass fiber, a lightweight aggregate such as perlite and vermiculite is kneaded with water to form a paste or slurry mixed composition as a base material. Inorganic powder containing wet rock wool or water of crystallization that is thickened by spraying or troweling on the surface, such as aluminum hydroxide,
Examples include inorganic binders such as cement, inorganic fibrous substances such as glass fibers, lightweight aggregates such as perlite and vermiculite, and ceramic-based fireproof coating materials kneaded with water.

[0003]

However, the construction with mortar has a fire resistance of 1 hour (when heated by the standard heating curve for 1 hour, the steel material temperature is 350 ° C or less on average and 450 ° C or less at the maximum temperature). Since it is as thick as 40 mm, thick coating cannot be performed at one time, and a curing period of about 2 weeks is required after every several coatings. Therefore, it took a lot of time and labor for construction. Further, the mortar itself is easily cracked, and when rainwater penetrates into the mortar from the inside, rust of lath wire nets and steel frames is induced, and there is a risk that the mortar will fall off in the long term. Further, the weight per unit area is large and the burden on the body is excessive, and there are cases where it is necessary to design the structure considering the weight. On the other hand, in the method of surrounding with a metal panel such as aluminum after spraying rock wool, due to rainfall until the construction of the metal panel,
It adversely affects rock wool fireproof coating material, which is inferior in water resistance,
There was always the danger of peeling and scraping. On the other hand, the processing of a metal panel is expensive and time-consuming, and it is difficult to process a particularly complicated connecting portion. That is, the sealing of the joint is likely to be insufficient, there is a risk of water leakage to the back surface of the metal panel even after construction, in that case there is a problem that the internal rock wool fireproof coating layer peels off like rain. . Furthermore, even when using a water-repellent calcium silicate plate, since it is a plate material, it is difficult to apply it to a complicated joint part like a panel, and it takes a lot of time to seal joints. Further, in the long term, water absorption into the material progressed due to deterioration of water repellency, and there was a high possibility that the material would be broken due to freezing. Next, when the wet fireproof coating alone is used, for example, the strength of the material is insufficient with wet rock wool, so the surface is scraped by rainfall, and the steel frame and lath rust due to water ingress into the material. Probability is high. Since the strength of the ceramic fireproof coating is higher than that of rock wool, the effect of rainfall is unlikely to occur in a short period of time, but in the long term, the surface is abraded and the rust of lath is similar to rock wool. To occur. It is an object of the present invention to solve the above problems and provide an external steel frame fireproof coating structure having desired fireproof performance over a long period of time.

[0004]

In order to solve such a problem, the inventors of the present invention have conducted diligent research and, as a result, have found that the problem with the conventional fire-resistant coating material to be used outside is that the infiltration of water due to rainfall or the like. It is conjectured that it can be concentrated on the problem of the above, first by waterproofing the fire resistant coating material to prevent moisture intrusion from the outside, and then by the water content contained in the fire resistant coating material in advance, the previous waterproofing In order to prevent the problem of the material being pushed up and swelling, the fire-resistant coating material has breathability that can diffuse moisture inside, and it is a wet material that is easy to construct even in complex parts such as steel frame The present invention has been completed by devising a method. That is, the present invention has a configuration as shown in the conceptual diagram of FIG. 1. On the surface of steel frame, (1) lath wire mesh, (2) wet fireproof coating layer with air permeability of 10 to 10000 (l / m ² min · 100 mmHg · 20 mm) when dried, and (3) waterproof layer were sequentially laminated. An external steel fireproof coating laminated structure characterized by the above. 2. On the surface of the steel frame, (1) lath wire mesh, (2) wet fireproof coating layer with air permeability of 10 to 10,000 (l / m ² min · 100 mmHg · 20 mm) when dried, (3) undercoat layer, (4 ) An external steel frame fireproof coating laminated structure characterized by sequentially laminating waterproof layers. 3. The waterproof layer has a tensile strength of 50 N / cm ² or more, a coating film elongation of 50% or more, and a water permeability of 0.5 ml / 24 h or less. Or 2. The external steel fireproof coating laminated structure according to. 4. 1. The wet fire-resistant coating material is a wet fire-resistant coating material mainly composed of cement, aluminum hydroxide, lightweight aggregate and filler. To 3. The steel frame fireproof coating laminated structure for external use according to any one of 1. 5. 1. A finishing layer is further laminated on the surface of the waterproof layer. To 4. The steel frame fireproof coating laminated structure for external use according to any one of 1. Can be given.

The steel frame used in the present invention is a structural steel material applied to general structures, for example, JIS G 3101.
Rolled steel for general structure, JIS G 3106 Rolled steel for welded structure, JIS G 3114 Weather resistant hot rolled steel for welded structure, JIS
G 3350 Lightweight steel for general structure, JIS G 3353 Welded lightweight H-shaped steel for general structure, JIS G 3444 Carbon steel pipe for general structure,
JIS G 3466 Square pipe for general structure, JIS G 5201 Centrifugal casting pipe for welded structure, fire resistant steel, JIS G 3601 stainless clad steel, etc., and those having a rust preventive layer on its surface are desirable. Such a rust preventive layer is formed by applying rust preventive paint for preventing rust on the steel frame, and JIS K 5621 general rust preventive paint, JI
SK 5622 red lead rust preventive paint, JIS K 5623 lead suboxide rust preventive paint, JIS K 5624 basic lead chromate rust preventive paint, JIS K 5625 cyanamide lead rust preventive paint, JIS K 5627 zinc chromate rust preventive paint Paint, JIS K 5628 lead zinc zinc chromate rust preventive paint, etc.

Lath wire mesh is a plaster mortar base material most suitable for fireproof construction, and generally includes metal lath and wire lath. A metal lath is an expanded lath that is made into a net by drawing cuts at regular intervals on a thin steel plate, and depending on its shape, flat lath, cobras,
Although there are corrugated lath and rib lath, rib lath is preferable in the present invention. A wire lath is a wire mesh made by knitting wire. Depending on the knitting method, there are rhombus, instep, and round shapes.
Expanded metal can also be used in the lath wire mesh of the present invention. When attaching these lath wire mesh to the steel frame, it is common to weld the reinforcing bar to the steel frame in advance and attach it to the reinforcing bar with wire, but if the size of the steel frame is not so large, wrap the lath wire mesh around the steel frame. It is also possible to wind the wire and then attach it.

The wet refractory coating material is not particularly limited as long as it has been conventionally used, but the breathability during drying is in the above-mentioned range, and the strength and fire resistance performance of the fire resistant coating material layer are taken into consideration. Then, it is desirable to use cement, aluminum hydroxide, lightweight aggregate, and filler as the main components. In particular, (a) cement, (b) re-emulsifiable powder synthetic resin and / or synthetic resin emulsion, (c) lightweight aggregate,
(d) Aluminum hydroxide as a main composition, (a) 100 parts by weight, (b) 3 to 50 parts by weight (solid content), (c) 2
It is most preferable that the content of 0 to 300 parts by weight and (d) 50 to 600 parts by weight are strength, fire resistance and breathability. The dry fire resistance of the wet fireproof coating material is 10 to 10,000.
The range is (l / m ² min · 100 mmHg · 20 mm), but 10
When it is smaller than (l / m ² min · 100 mmHg · 20 mm), water enters from the joint of the steel frame, etc., and when it is impregnated into the fireproof coating material, steam will be generated due to a rapid temperature rise due to direct sunlight etc. The generated water vapor pushes up the undercoat layer or waterproof layer to swell. Further, since the refractory coating material has high density and high strength, shrinkage is large, and cracks may occur in the refractory coating material itself. 1
When it is more than 0000 (l / m ² min · 100 mmHg · 20 mm), the strength of the fireproof coating material decreases, the original adhesive strength of the coating film cannot be maintained, and the undercoat layer or waterproof layer peels off. The method for measuring the air permeability during drying is to use the air permeability measuring device shown in Fig. 2 to send air while gradually increasing the pressure from the air pump, and to measure the amount of air passing through the test body at that time. Unit area (m ² ), unit time (min), from the primary curve obtained from the pressure and flow rate data obtained by measuring with a meter,
It is expressed in terms of constant pressure (100 mm Hg) and constant thickness (20 mm). In addition, in cases other than complicated parts such as steel frame fittings, the method of attaching such a wet refractory coating material that has been preformed can save the time and effort of spraying and become more efficient.

The waterproof layer is not particularly limited as long as it is in close contact with the wet fire-resistant coating material, prevents water from entering from the outside, and ensures the durability of the wet fire-resistant coating material at the initial level. Such items include sheet waterproofing and coating waterproofing. The sheet waterproofing is a waterproofing method in which a waterproofing sheet such as vinyl chloride or vulcanized rubber is adhered to the body through an undercoat material (adhesive). It is a waterproof construction method using a waterproof coating film formed by applying it to the body with a roller or spraying. As a fireproof coating material, wet type is used, taking advantage of the fact that it can be easily applied to complex parts such as steel frames. desirable. Such a waterproof layer has a tensile strength of 50 N / cm ² or more in a standard state at 20 ° C., a coating film elongation rate of 50% or more, and a water permeability of 0.5 ml / 24 h or less. As an effect of the invention, it is possible to more remarkably maintain the performance of the fireproof coating material outside for a long time. As a waterproof layer having the above physical properties, it is desirable to use JI
SA 6021 roof waterproof film, JIS A 6910 multi-layer finish coating, waterproof type main material, etc. The tensile strength of the waterproof layer and the elongation of the coating film are based on JIS K 5400 8.8 "Tensile strength and elongation", and the water permeability is JIS K
5400 8.16 Measure in accordance with the provisions of “water permeability”. still,
In the case where the waterproof layer is a sheet waterproof or a coating waterproof, if the adhesion with the fireproof coating material is poor, it is necessary to apply the waterproof layer after applying the undercoat material (adhesive material) to the fireproof coating material. As such an undercoat layer, various adhesives such as acrylic, urethane, and epoxy-based adhesives, acrylic, urethane, epoxy,
Solvent-based sealers such as chlorinated polyolefins, water-based sealers, polymer cements composed of emulsion and cement, elastic polymer cements and the like can be used.

The external steel frame fireproof coating laminated structure of the present invention comprises:
Although the effect can be obtained by the above-mentioned configuration, it is desirable to further provide a finishing layer on the surface of the waterproof layer in order to further improve the appearance and durability of the waterproof layer. Such a finishing layer is not particularly limited as long as it can adhere to a waterproof layer having elasticity, for example, JIS K 5654 “acrylic resin enamel”, JIS K 5656 “building polyurethane resin paint”, JIS K 5658 “building Fluorocarbon Resin Paint ", J
IS K 5660 "Shiny synthetic resin emulsion paint, JIS
K 5663 "Synthetic Resin Emulsion Paint", JIS K 566
7 "Multicolored paint", JIS K 5668 "Synthetic resin emulsion pattern paint", acrylic modified silicone paint, water-based acrylic modified silicone paint, etc. Is desirable.

[0010]

【Example】

(Example 1) <Breathability test method> Water for kneading was added to the formulation examples shown in Table 1 to prepare a wet fire-resistant coating material slurry, which was poured into a mold to cure, demold, and face each other. The distance between the two sides is 60
An octagonal substrate having a thickness of 20 mm and having a thickness of mm was manufactured.
A 50 mmφ non-coated surface was left on the front and back surfaces of this substrate, and the other portions were covered with an epoxy resin adhesive and cured. After that, the surface of the epoxy resin adhesive was ground with sandpaper, sandwiched between the attachment m as shown in FIG. 3 and the sealing packing n, and then set in the breathability measuring device as shown in FIG. The breathability measuring device is an air pump h
From the above, the air whose pressure is measured by the pressure gauge j is pressure-fed through the pressure regulating valve i and introduced into the test body mounting portion. On the other hand, the air discharged from the test piece mounting part is flow meter k
The flow rate per minute is measured in liters.
The test piece mounting portion is as shown in FIG. 4, and air is allowed to pass through a portion (50 mmφ) other than the portion where the substrate is coated with the epoxy resin adhesive as described above. From the linear curve obtained from the pressure and flow rate data thus measured, the unit area (m ² ) and the unit time (min
), Constant pressure (100 mm Hg), constant thickness (20 mm), the air permeability when dried is 6454 (l / m ² min · 10)
It was 0 mmHg · 20 mm). <Compressive Strength> Next, the wet refractory coating material slurry is poured into a mold to cure and demold, and a cross section of 40 × 40 × 160.
A rectangular column having a size of mm was prepared, and the compression strength was measured based on JIS A 1172 "Polymer cement mortar strength test method" to find that it was 67 N / cm ² . <Bulk Density> The weight of the prism formed at the time of measuring the compressive strength was measured to calculate the bulk density, which was 0.51 g / cm ³ . <Swelling of coating film> Next, the wet fire-resistant coating material slurry is poured into a mold to cure and demold, and 300 × 300 × 20
A mm substrate was prepared. After sufficiently drying this substrate, as shown in FIG. 5, a chlorinated rubber sealer (“Lena Excellent undercoat material” manufactured by SK Kaken Co., Ltd.) was applied as an undercoat layer e at a coating amount of 0.20 kg / m ² . After drying the undercoat layer, an acrylic rubber roof coating film waterproof material (“Lena Excellent A” manufactured by SK Kaken Co., Ltd.) was applied as a waterproof layer f at a coating amount of 2.4 kg / m ² , followed by finishing. As the layer g, a solvent-type two-liquid reaction type elastic urethane enamel (“elastic urethane color” manufactured by SK Kaken Co., Ltd.) was applied. Curing for 14 days after painting (20 ℃, 65
% RH) was immersed in water for 7 days to obtain a test body. The coating film surface of this test body was heated by a ceramic heater o as shown in FIG. 5 and kept at 70 ° C. at maximum for 6 hours. <Weather resistance> Next, on a 1000 × 400 × 5 mm iron plate,
Weld a reinforcing bar of mmφ, and then attach a rib lath to the reinforcing bar with a wire. The wet fire-resistant coating material slurry is applied to the rib lath with a trowel to a thickness of 20 mm. When the test piece thus produced was exposed to the outdoors for 1 year and checked for the occurrence of cracks, no cracks were found. (Example 2 to Comparative Example 2) Each test was performed in the same manner as in Example 1 except that the fire resistant coating material produced according to the formulation example shown in Table 1 was used. The results are shown in Table 2.

[Table 1]

[Table 2]

[0011]

Industrial Applicability According to the present invention, it becomes possible to maintain the performance of a steel frame refractory coating for a long period even when it is used outside. In particular, since a wet type fireproof coating material is used, it is excellent in that it can be easily installed on a complicated joint.
Further, in the present invention, when the wet fireproof coating used is made of lightweight aggregate, aluminum hydroxide, filler, etc., the weight per unit area is lighter than that of mortar, and the fireproof performance for one hour is as thin as 20 mm. The construction of fireproof coating is quick. Furthermore, since the fire-resistant coating material has a specific breathability, even if moisture penetrates from other parts such as the steel frame's mating portion and the fire-resistant coating material contains water, The contained water can be diffused. On the other hand, since the waterproof layer has elasticity, it can follow the vibration and flexure of the steel frame and the fireproof coating, and the expansion and contraction due to heat, and the swelling of the finishing layer caused by the intrusion of rainwater from the outside. It is possible to prevent destruction of the fireproof coating material due to frost damage.

[Brief description of drawings]

FIG. 1 is a conceptual sectional view of an external steel frame fireproof coating laminated structure.

FIG. 2 is a schematic view of a breathability measuring device.

FIG. 3 is a plan view of an attachment that holds a test body in a breathability measuring device.

FIG. 4 is a cross-sectional view of a test body mounting portion in the breathability measuring device.

FIG. 5 is an explanatory diagram showing a test body and a test method for swelling of a coating film with a water-containing fireproof coating material.

[Explanation of symbols]

 a steel frame b rebar c riblas d fireproof coating layer e undercoat layer f waterproof layer g finishing layer h air pump i pressure control valve j pressure gauge k flow meter m attachment n seal packing o ceramic heater

Claims (5)

[Claims] 1. A steel frame surface having 1. Lath wire mesh, 2. Air permeability when dried is 10 to 10,000 (l / m ² min · 100 mmHg · 20)
mm) wet refractory coating, 3. An external steel fireproof coating laminated structure characterized by sequentially laminating waterproof layers. 2. On the surface of the steel frame, 1. Lath wire mesh, 2. Air permeability when dried is 10 to 10,000 (l / m ² min · 100 mmHg · 20)
mm) wet refractory coating layer, 3. Subbing layer, 4. An external steel fireproof coating laminated structure characterized by sequentially laminating waterproof layers. 3. The waterproof layer has a tensile strength of 50 N / cm ² or more, a coating film elongation of 50% or more, and a water permeability of 0.5 ml / 24 h or less (both are at 20 ° C., standard condition). The steel frame fireproof coating laminated structure for external use according to claim 1 or 2. 4. The wet refractory coating material is a wet refractory coating material containing cement, aluminum hydroxide, lightweight aggregate and filler as main components. The external steel frame fireproof coating laminated structure described. 5. The external steel frame fireproof coating laminated structure according to any one of claims 1 to 4, wherein a finishing layer is further laminated on the surface of the waterproof layer.