Metal Ventilation pipe construction Specification for sealant used in
At present, there are two ventilation and air conditioning engineering specifications in use. One is the Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Works (GB50243-2016) implemented on July 1, 2017, and the other is the Code for Construction of Ventilation and Air Conditioning Works (GB50738-2011) issued on September 16, 2011 and implemented on May 1, 2012.
The two specifications both put forward requirements for gluing of metal air duct.
1、 Code for Acceptance of Construction Quality of Ventilation and Air Conditioning Engineering GB50243-2016
Ventilation engineering The sealing of the air duct under construction shall be based on the sealing of plate connection, and sealant caulking and other methods can also be used. The performance of the sealant should meet the requirements of the use environment, and the sealing surface should be located at the positive pressure side of the air duct.
（2） Interpretation of this article:
1. The sealing of air duct shall be mainly plate connection sealing; Caulking with sealant is a secondary method, not a primary method;
2. Sealant and other methods can be used for sealing; Sealant caulking is only one of the secondary sealing methods, not the only sealing method. There are other sealing methods (including solder sealing);
3. The performance of sealant used for metal air duct caulking shall meet the requirements of the use environment:
(1) One side of the caulking sealant shall be pasted on the plate of the metal air duct, which shall be consistent with the expansion coefficient of the metal material of the air duct;
(2) The sealant side of the caulking shall be in contact with the air flow in the air duct (or with the ambient air), and it shall be able to adapt to the temperature of the air in contact;
four Ventilation duct No matter what secondary method is used for construction, the sealing surface shall be at the positive pressure side.
2、 Code for Construction of Ventilation and Air Conditioning Engineering GB50738-2011
（1） The provisions on the use of sealant in Paragraph 5 of Article 4.2.15 on air duct reinforcement are as follows: the air duct of clean air conditioning system shall not be internally reinforced or reinforced, and the reinforcement points inside the air duct or around flange riveting points shall be sealed with sealant.
（2） The use of sealant in the first paragraph of 4.2.11 for sheet steel flange (common plate) air duct forming is as follows:
The interfaces at both ends of the thin steel flange air duct shall be flat, and the four corners of the interface shall be provided with fixed corner pieces, which are made of galvanized steel plate, and the thickness of the plate shall not be less than 1.0mm. The joint between the fixed angle piece and the flange shall be sealed with sealant.
It can be seen from the above two items that the Code for Construction of Ventilation and Air Conditioning Engineering (GB50738-2011) is cautious about the use of sealant. It only uses sealant in two cases: one is to seal the air leakage points caused by air duct reinforcement; The second is in the thin steel plate flange（ Common plate flange ）Glue the four corners.
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