What does A-0 in fire rating mean

What does A-0 in fire rating mean

As in the title, "A" class division means a division consisting of bulkheads and decks which meet the following criteria:

1. they are made of steel or other equivalent material;

2. they have proper anti flex reinforcement;

3. They are insulated with an approved non combustible material so that the average temperature of the back fire side does not increase by more than 140 ℃ from the initial temperature during the following periods, and the temperature at any point including any joint does not exceed 180 ℃.

“A–60” Class     60 min

“A–30” Class     30 min

“A–15” Class     15 min

  "A –0"   Class     0 min

4. they shall be constructed to prevent the passage of smoke and flame at the end of the 1 h standard fire resistance test.

5. the competent authority has required a test on prototype bulkheads or decks in accordance with the code for fire resistance test procedures to ensure that the above integrity and temperature rise requirements shall be met.

Many people don't understand the meaning of 60min, 30min, 15min, especially 0 min.

The meaning of "A-60" 60 min means that the average temperature of the back fire side of the wall is not more than 140 ℃ higher than the initial temperature when it is burned for 60 minutes on one side of the wall, and the temperature at any point, including any joint, does not rise more than 180 ℃ from the initial temperature. 4. They shall be constructed to prevent smoke and flame from passing through at the end of one hour standard fire resistance test.

Similarly, "a – 30 / 15 / 0" class 30 / 15 / 0 min means that the average temperature of the back fire side of the wall is not more than 140 ℃ higher than the initial temperature, and the temperature at any point, including any joint, does not exceed 180 ℃ higher than the initial temperature. 4. The structure of the wall shall be able to prevent smoke and flame from passing through at the end of the 1 h standard fire resistance test.

The A0 level means that there is no requirement for the temperature rise of the back fire surface.