How to determine whether a fire-retardant coating is good or not
Release Time:
2015-08-20
Source:
How to determine whether a fire-retardant coating is good or not
Fire-retardant coatings look very similar to ordinary paints, making it difficult to distinguish them by appearance alone, and it is also challenging to assess their quality on-site. So, in practical construction projects, how can one determine whether a fire-retardant coating is of good quality? Fire safety supervision authorities at all levels can employ the following methods for evaluation:
Verify whether the product is accompanied by a certificate of compliance issued by a national-level fire protection quality inspection center; this information can also be verified online. Currently, fire-retardant coatings are subject to a type-approval system for fire-protection products, meaning that all fire-retardant coatings sold on the market must possess a National Fire Protection Product Type-Approval Certificate and a Type-Test Compliance Report. According to national standards, In addition to meeting fire-stopping requirements, the combustion performance of fire-resistant coatings is classified into Grade 1 and Grade 2. Under specified test conditions, Grade 1 fire-resistant coatings must have a fire-resistance duration of no less than 20 minutes, while Grade 2 coatings must have a heat-resistance duration of no less than 10 minutes. When making a selection, users should pay close attention to these distinctions to prevent manufacturers from passing off inferior products as superior. To achieve fire protection effectiveness.
On-site application of fire-resistant coatings shall be carried out in accordance with the instructions on the manufacturer’s product packaging; generally, no water dilution is required. The coating should be applied in two or more coats, with a minimum application rate of 500 grams per square meter. If the fire-resistant coating is diluted with water or the application rate is insufficient, its fire-resistance performance will be significantly compromised, posing a fire safety hazard. Departments should strengthen oversight of construction sites to prevent construction companies from cutting corners and using substandard materials.
Qualified fire-retardant coatings, when exposed to intense flames such as those from a blowtorch, will undergo substantial foaming and expansion, with the surface forming raised bumps; no signs of burn-through will appear within several minutes. In contrast, counterfeit or substandard fire-retardant coatings exhibit little to no foaming and instead tend to crumble and flake off in large quantities, while the wood substrate will quickly ignite and suffer severe damage. If there is a… Additionally, a preliminary inspection of the product quality can be carried out on site: cut 2–3 small samples from the already constructed substrate, or apply a small amount of the sample to 2–3 pieces of 150 mm × 150 mm plywood, applying it in accordance with the actual construction conditions. After complete drying, examine the coating using the flame of an alcohol lamp, with a flame height of approximately 40 mm, applying the flame… The flaming test is typically conducted for 20 minutes to inspect the foaming behavior of the coating. Under normal conditions, when applied at the specified dosage (generally 500 g/m²), the expanded foam layer of Class I fire-resistant coatings should be at least 20 mm thick, while that of Class II fire-resistant coatings should be at least 10 mm thick; moreover, the foam layer must be uniform and dense.
In practical applications, to ensure the fire-retardant and other performance characteristics of fire-resistant coatings, a transparent topcoat is generally applied. The typical application rate for the fire-resistant coating is 350–500 g/m², while that for the topcoat is usually 50 g/m².
The application of fire-retardant coatings has expanded steadily with the trends toward larger-scale industrial operations and the clustering and high-rise development of buildings, as well as with continuous advances in science and technology. In the past, these coatings were primarily used to prevent fires in warehouses, ships, and similar facilities; today, they are increasingly designed to meet more stringent requirements, including higher temperature resistance and longer fire-resistance durations. At the same time, it can also keep the underlying temperature within a relatively low range. However, as a new type of paint, fire-retardant coatings still have certain drawbacks, such as higher costs and less-than-ideal physical properties in some formulations. Currently, the variety of fire-retardant coatings continues to expand, and the market prospects are expected to be promising.
