Why does the fire protection coating of steel structure engineering appear unequal defects?

After the construction of the fireproof coating of steel structure engineering is completed and dried, there will always be delamination or hollow drum, obvious depression on the surface, uneven appearance, mastoid phenomenon or hand breaking, powder loose and floating pulp and other defects, resulting in rework, so how are these problems formed? How to deal with it?

[Analysis of the causes of delamination and unequal defects in the fire protection coating of steel structure]

(1) If the coating is too thick, it is easy to crack, hollow and fall off (delamination) due to the different drying speed inside and outside.

(2) The coating is applied in the bottom (or base) where there is oil, dust, sand and other dirt or condensation, etc., or does not hang the wire mesh according to the product requirements, and brushes the interface agent, causing the coating to empty and fall off (delamination).

(3) Construction under high temperature and scorching sun, without paying attention to basic treatment and coating maintenance, causing the coating to hollow and fall off (coating).

(4) The coating construction is carried out without taking measures under high temperature or cold environmental conditions, causing the coating to powder or freeze during construction, and the coating is not dry and solidified after construction, causing defects such as weak bonding, loose powder and floating slurry.

(5) The construction is not standardized, the screed cover is not made, and the mastoid process is not removed.

In the "Steel structure engineering construction quality acceptance Code" GB50205-2001 provisions: Article 14.3. 6 coating should have no delamination, hollow drum, obvious concave, powder loose and floating paddle appearance defects, these problems we should be in accordance with the construction technology disclosure of the steel structure fire coating repair until qualified.