Fireproof coating thickness
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The safety level for steel structure design is grade 2; the fireproof coating used is an ultra-thin type. What should be the thickness of this fireproof coating? I’ve looked up a lot of information (GB14907-2002 for fire-resistant coatings on steel structures), and I only found that the fire resistance time is 1 hour and the coating thickness is 2 mm. What is the fire resistance time for the second safety grade?
It is recommended that you refer to Section 3.2 of the \"Code for Fire Protection Design of Buildings GB50016-2006\", which deals with the fire resistance ratings of factories (warehouses) and the fire resistance limits of their components. 3.2 Fire resistance ratings of factories (warehouses) and fire resistance limits of components: 3.2.1 The fire resistance ratings of factories (warehouses) can be classified into four levels: first, second, third, and fourth. Unless otherwise specified in these codes, the combustion performance and fire resistance rating of its components shall not be lower than those specified in Table 3.2.1. Table 3.2.1 Combustion performance and fire resistance limit (hours) of building components in factories (warehouses)
| Name | Fire resistance rating | Component | Grade 1 | Grade 2 | Grade 3 | Grade 4 |
|------|------------------------|-----------|---------|---------|---------|---------|
| Wall | Fire wall | Non-combustible material | Non-combustible material | Non-combustible material | Non-combustible material | 3 | 3 | 3 | 3 |
| | Load-bearing wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 3 | 2.5 | 20.5 | |
| Stairwells and elevator shafts | Wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 2 | 2 | 1.5 | 0.5 |
| Partition walls on both sides of evacuation walkways | Wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 1 | 1 | 0.5 | 0.25 |
| Non-load-bearing exterior walls | Wall | Non-combustible material | Non-combustible material | Slow-burning material | Slow-burning material | 0.75 | 0.5 | 0.5 | 0.25 |
| Room partition walls | Wall | Non-combustible material | Non-combustible material | Slow-burning material | Slow-burning material | 0.75 | 0.5 | 0.5 | 0.25 |
| Columns | Column | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 3 | 2.5 | 20.5 | |
| Beams | Beam | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 2 | 1.5 | 10.5 | |
| Floor slabs | Floor slab | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 1.5 | 10.75 | 0.5 | |
| Roof load-bearing components | Component | Non-combustible material | Non-combustible material | Slow-burning material | Combustible material | 1.5 | 10.5 | | |
| Evacuation stairs | Stair | Non-combustible material | Non-combustible material | Non-combustible material | Combustible material | 1.5 | 10.75 | | |
| Ceilings (including ceiling grids) | Ceiling | Non-combustible material | Slow-burning material | Slow-burning material | Combustible material | 0.25 | 0.25 | 0.15 | |
Note: For ceilings in buildings with a fire resistance rating of Grade 2, if non-combustible materials are used, there is no specified fire resistance limit. 3.2.2 For firewalls in the following buildings, their fire resistance rating shall be increased by 1.00 hour in accordance with the provisions of Table 3.2.1 of this code: 1 Factories of Class A and Class B ； 2 Class A, B, and C warehouses. 3.2.3 For the columns of single-story factories (warehouses) with fire resistance ratings of Class I or II, their fire resistance limit may be reduced by 0.50 hours in accordance with the provisions of Table 3.2.1 of this code. 3.2.4 For the beams and columns of buildings with a secondary fire resistance rating as listed below, metal structures without fire protection may be used; however, in those parts that are exposed to flames from Class A, B, or C liquids or flammable gases, non-combustible materials should be applied as an outer coating or other fire and heat insulation measures must be implemented: 1 Single-story Class C factories equipped with automatic fire suppression systems ； 2 Class D and E factories (warehouses). 3.2.5 Non-load-bearing exterior walls of buildings with fire resistance ratings of Class I and II shall comply with the following provisions: 1 Except for Class A and B warehouses as well as high-rise warehouses, when non-load-bearing exterior walls are made of non-combustible materials, their fire resistance limit shall not be less than 0.25 hours ； When non-combustible materials are used, it should not be less than 0.50 hours: for above-ground factories (warehouses) of Class D and E with 2 to 4 floors or fewer, there is no limit on the fire resistance rating when non-load-bearing exterior walls are made of non-combustible materials ； When non-load-bearing exterior walls are made of lightweight composite walls made of flame-retardant materials, their surface materials should be non-combustible, and the combustion performance of the interior filling materials should not be lower than grade B2. Materials of grades B1 and B2 shall meet the relevant requirements of the current **standard \"Method for Classifying the Burning Performance of Building Materials\" GB8624. 3.2.6 For the partition walls in rooms within factories (warehouses) with a secondary fire resistance rating, if flame-retardant materials are used, their fire resistance limit shall be increased by 0.25 hours. 3.2.7 In multi-story factory buildings or warehouses with a secondary fire resistance rating, when prestressed or precast reinforced concrete floor slabs are used, their fire resistance limit shall not be less than 0.75 hours. 3.2.8 For the walkable flat roofs of factories (warehouses) with fire resistance ratings of Class I and Class II, the fire resistance limit of their roof panels shall be not less than 1.50 hours and 1.00 hour respectively. In single-story or multi-story factories (warehouses) with a fire resistance rating of Class 1, when an automatic **fire extinguishing system is used for comprehensive protection, the fire resistance limit of the roof’s structural members shall not be less than 1.00 hour. The roof load-bearing members of buildings with a fire resistance rating of Class 2 may be metal members without a protective coating; however, those parts that are exposed to the flames of liquids of Classes A, B, and C must be equipped with fire and heat insulation protection measures. 3.2.9 For factories (warehouses) with fire resistance ratings of Class I or II, the roof panels shall be made of non-combustible materials; however, the roof waterproofing layer and insulation layer may be made of combustible materials ； When buildings (warehouses) of Class D and E have no more than 4 floors, their roofs may use lightweight composite roof panels made of flame-retardant materials; however, the surface material of such panels must be non-flammable, and the combustion performance of the filling material inside should be at least grade B2. 3.2.10 Unless otherwise specified in these codes, for factories (warehouses) with wooden columns bearing the load and walls made of non-combustible materials, their fire resistance rating shall be determined as grade four. 3.2.11 Fire protection measures shall be taken for the exposed parts of joints in precast reinforced concrete members, and the fire resistance limit of such joints shall not be lower than that specified for the corresponding members. This post was last edited by hw197358 on 2009-3-18 12:26.]
| Name | Fire resistance rating | Component | Grade 1 | Grade 2 | Grade 3 | Grade 4 |
|------|------------------------|-----------|---------|---------|---------|---------|
| Wall | Fire wall | Non-combustible material | Non-combustible material | Non-combustible material | Non-combustible material | 3 | 3 | 3 | 3 |
| | Load-bearing wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 3 | 2.5 | 20.5 | |
| Stairwells and elevator shafts | Wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 2 | 2 | 1.5 | 0.5 |
| Partition walls on both sides of evacuation walkways | Wall | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 1 | 1 | 0.5 | 0.25 |
| Non-load-bearing exterior walls | Wall | Non-combustible material | Non-combustible material | Slow-burning material | Slow-burning material | 0.75 | 0.5 | 0.5 | 0.25 |
| Room partition walls | Wall | Non-combustible material | Non-combustible material | Slow-burning material | Slow-burning material | 0.75 | 0.5 | 0.5 | 0.25 |
| Columns | Column | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 3 | 2.5 | 20.5 | |
| Beams | Beam | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 2 | 1.5 | 10.5 | |
| Floor slabs | Floor slab | Non-combustible material | Non-combustible material | Non-combustible material | Slow-burning material | 1.5 | 10.75 | 0.5 | |
| Roof load-bearing components | Component | Non-combustible material | Non-combustible material | Slow-burning material | Combustible material | 1.5 | 10.5 | | |
| Evacuation stairs | Stair | Non-combustible material | Non-combustible material | Non-combustible material | Combustible material | 1.5 | 10.75 | | |
| Ceilings (including ceiling grids) | Ceiling | Non-combustible material | Slow-burning material | Slow-burning material | Combustible material | 0.25 | 0.25 | 0.15 | |
Note: For ceilings in buildings with a fire resistance rating of Grade 2, if non-combustible materials are used, there is no specified fire resistance limit. 3.2.2 For firewalls in the following buildings, their fire resistance rating shall be increased by 1.00 hour in accordance with the provisions of Table 3.2.1 of this code: 1 Factories of Class A and Class B ； 2 Class A, B, and C warehouses. 3.2.3 For the columns of single-story factories (warehouses) with fire resistance ratings of Class I or II, their fire resistance limit may be reduced by 0.50 hours in accordance with the provisions of Table 3.2.1 of this code. 3.2.4 For the beams and columns of buildings with a secondary fire resistance rating as listed below, metal structures without fire protection may be used; however, in those parts that are exposed to flames from Class A, B, or C liquids or flammable gases, non-combustible materials should be applied as an outer coating or other fire and heat insulation measures must be implemented: 1 Single-story Class C factories equipped with automatic fire suppression systems ； 2 Class D and E factories (warehouses). 3.2.5 Non-load-bearing exterior walls of buildings with fire resistance ratings of Class I and II shall comply with the following provisions: 1 Except for Class A and B warehouses as well as high-rise warehouses, when non-load-bearing exterior walls are made of non-combustible materials, their fire resistance limit shall not be less than 0.25 hours ； When non-combustible materials are used, it should not be less than 0.50 hours: for above-ground factories (warehouses) of Class D and E with 2 to 4 floors or fewer, there is no limit on the fire resistance rating when non-load-bearing exterior walls are made of non-combustible materials ； When non-load-bearing exterior walls are made of lightweight composite walls made of flame-retardant materials, their surface materials should be non-combustible, and the combustion performance of the interior filling materials should not be lower than grade B2. Materials of grades B1 and B2 shall meet the relevant requirements of the current **standard \"Method for Classifying the Burning Performance of Building Materials\" GB8624. 3.2.6 For the partition walls in rooms within factories (warehouses) with a secondary fire resistance rating, if flame-retardant materials are used, their fire resistance limit shall be increased by 0.25 hours. 3.2.7 In multi-story factory buildings or warehouses with a secondary fire resistance rating, when prestressed or precast reinforced concrete floor slabs are used, their fire resistance limit shall not be less than 0.75 hours. 3.2.8 For the walkable flat roofs of factories (warehouses) with fire resistance ratings of Class I and Class II, the fire resistance limit of their roof panels shall be not less than 1.50 hours and 1.00 hour respectively. In single-story or multi-story factories (warehouses) with a fire resistance rating of Class 1, when an automatic **fire extinguishing system is used for comprehensive protection, the fire resistance limit of the roof’s structural members shall not be less than 1.00 hour. The roof load-bearing members of buildings with a fire resistance rating of Class 2 may be metal members without a protective coating; however, those parts that are exposed to the flames of liquids of Classes A, B, and C must be equipped with fire and heat insulation protection measures. 3.2.9 For factories (warehouses) with fire resistance ratings of Class I or II, the roof panels shall be made of non-combustible materials; however, the roof waterproofing layer and insulation layer may be made of combustible materials ； When buildings (warehouses) of Class D and E have no more than 4 floors, their roofs may use lightweight composite roof panels made of flame-retardant materials; however, the surface material of such panels must be non-flammable, and the combustion performance of the filling material inside should be at least grade B2. 3.2.10 Unless otherwise specified in these codes, for factories (warehouses) with wooden columns bearing the load and walls made of non-combustible materials, their fire resistance rating shall be determined as grade four. 3.2.11 Fire protection measures shall be taken for the exposed parts of joints in precast reinforced concrete members, and the fire resistance limit of such joints shall not be lower than that specified for the corresponding members. This post was last edited by hw197358 on 2009-3-18 12:26.]
The specific thickness may depend on the information provided by the paint manufacturer.
Thank you, it can be used as a reference
These days, many just apply it casually to deceive the fire department and get approval. But some places are also equipped with thickness gauges