Can common plate flange duct be used in fire protection smoke exhaust duct system?

1, metal rectangular duct thin steel plate flange connection technology, according to the different forms of processing differences: flange and duct wall as a whole form, called the “common plate flange tube”, “no flange duct” or called “TDC Flange duct”; another is ‘combined flange’ duct (also called TDF flange), the thin steel plate flange with a special combination of flange machine made into a flange in the form of a flange, according to the length of the air duct material, inserted into the end of the wall of the made duct, and then riveted (pressed) together as a whole.

2, thin steel plate flange duct (i.e. common plate flange duct) from 2005 to promote a different range of domestic, to 2007 formed a related standard process and standard atlas “thin steel plate flange duct production and installation” 07K133.
 

3、Thin steel plate flange duct (i.e. common plate flange duct) its production technology is the most advanced in China, the use of fully automated assembly line to complete a variety of processing procedures, high production efficiency, accurate dimensions, good molding quality. Compared with the traditional angle steel flange duct, it saves steel, easy and fast construction operation, saves the construction site occupation, reduces the production noise, and has more cost advantages. More and more widely used in engineering construction, first in civil construction projects for a wide range of applications, and gradually expand to the subway, tunnel, civil aviation projects and other fields.

Thin steel plate flange duct connection is generally divided into the following four ways:

1、Flange insert fixing method

2、Spring clip fixing method

3、Top wire card fixing method

4、Bolt fixing method

In the actual use of the process, the second type of spring clip fixed way is the most widely used way, but the construction of the project if you do not pay attention to the construction details, or did not place a good bedding, or the installation of the completed duct due to the displacement of external forces, loose and other reasons for the impact of the spring clip fixed connection is very easy to cause air leakage duct.

 

Third, with the traditional angle iron flange connection mode of comparison

Traditional duct connection, the flange is generally made of angle iron (therefore also known as angle iron flange), angle iron is usually fixed at both ends of the duct by riveting, the flange of the two sections of the duct is butt jointed, and the center with a gasket is connected with bolts. The advantages of angle iron flange connection are high strength, good stability and sealing, not easy to deform, the disadvantage is higher cost and lower efficiency.

Fourth, “smoke control and exhaust technology standards” in the relevant provisions of the

According to the “building smoke and exhaust system technical standards” GB51251-2017 (hereinafter referred to as the “smoke and exhaust prevention and control technical standards”) on the construction of thin steel ducts, the relevant provisions are as follows:

1. Article 6.3.1 of the Technical Standard for Smoke and Smoke Prevention and Exhaustion:

The fabrication and connection of metal air ducts shall comply with the following provisions:

When the duct is connected by flange, the duct flange material specifications should be selected in accordance with Table 6.3.1 of this standard, and the spacing of the bolt holes shall not be greater than 150mm, and there shall be screw holes at the corners of the rectangular duct flange;

The installation of air duct shall comply with the following provisions:

(1) air duct specifications, installation location, elevation, direction should be consistent with the design requirements, and the installation of the field air duct shall not reduce the effective cross-section of the interface.

(2) The connection of air duct interface should be tight and firm, and the thickness of gasket should not be less than 3mm, and it should not be convex into the pipe and flange; the flange gasket of smoke exhaust duct should be non-combustible material, and the flange of thin sheet steel duct should be connected by bolts.

(3) The installation of air duct hanging and bracket should be carried out according to the relevant provisions of the current national standard “Ventilation and Air Conditioning Engineering Construction Quality Acceptance Specification” GB 50243. 

(4) The connection between air duct and fan should be connected by flange or flexible short pipe of non-combustible material. When the fan is only used for smoke prevention and smoke exhaust, it is not suitable to adopt flexible connection.

As can be seen from the relevant provisions and clauses of the Technical Standard for Building Smoke Prevention and Exhaust System GB51251-2017 and the Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Projects GB50243-2016, thin steel sheet flange duct (common plate flange duct) is an important processing and production method of fire protection and smoke evacuation metal duct, and due to the maturity of its processing process, convenient molding, and more cost advantages, it can be Because of its mature processing technology, convenient molding and more cost advantage, it can be widely used in fire protection smoke exhaust duct system. In order to ensure the stability and reliability of the smoke exhaust system, the common plate flange duct must be connected by bolts, and the flange gasket should be non-combustible material.