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Fire
The following passive fire protection definitions are those most widely used and accepted throughout the industries we serve. Covered are:
Standard Fire Test
A standard fire test is one in which specimens of the relevant bulkheads or decks are exposed in a test furnace to temperatures corresponding approximately to the standard time-temperature curve. The specimen shall resemble as closely as possible the intended construction and include, where appropriate, at least one joint. The standard time-temperature curve is defined by a smooth curve drawn through the following temperature points measured above the initial furnace temperature.
At the end of the first
(minutes) |
Temperature
(°C)
|
| 5 |
556 |
| 10 |
659 |
| 15 |
718 |
| 30 |
821 |
| 60 |
925 |
“A” Class Divisions
“A” class divisions are those divisions formed by bulkheads and decks which comply with:
- They shall be constructed of steel or other equivalent material;
- They shall be suitably stiffened;
- They shall be so constructed as to be capable of preventing the passage of smoke and flame to the end of the one-hour standard fire test;
- They shall be insulated with materials, so that if either face is exposed, the average temperature of the unexposed side will not rise more than 140°C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 180°C above the original temperature, within the time listed below:
| Class |
Minutes |
| A-60 |
60 |
| A-30 |
30 |
| A-15 |
15 |
| A-0 |
0 |
“B” Class Divisions
“B” class divisions are those divisions formed by bulkheads, decks, ceiling or linings which comply with the following:
- They shall be so constructed as to be capable of preventing the passage of flame to the end of the first half hour of the standard fire test;
- They shall have an insulation value, so that if either face is exposed, such that the average temperature of the unexposed side will not rise more than 140°C above the original temperature, nor will the temperature at any one point, including any joint, rise more than 225°C above the original temperature, within the time listed below:
| Class |
Minutes |
| B-15 |
15 |
| B-0 |
0 |
- They shall be constructed of approved non-combustible materials and all materials entering into the construction and erection of “B” class divisions shall be non-combustible, with the exception that combustible veneers may be permitted.
“C” Class Divisions
“C” class divisions are divisions constructed of approved non-combustible materials. They need meet neither requirements relative to the passage of smoke and flame nor limitations relative to the temperature rise. Combustible veneers may be permitted.
Hydrocarbon Fire Classifications
A hydrocarbon fire test (pool fire) is one in which specimens of the relevant divisions or structural members are exposed in a test furnace to temperatures corresponding appropriately to a hydrocarbon time-temperature curve. The specimens shall resemble as closely as possible the intended construction and include, where appropriate, at lease one joint. The hydrocarbon curve is defined by a smooth curve drawn through the following (typical) temperature points measured above the initial furnace temperature (based on the Norwegian Petroleum Directorate (NPD) hydrocarbon curve):
At the end of the first
(minutes)
|
Temperature
(°C)
|
| 3 |
890 |
| 5 |
926 |
| 10 |
982 |
| 30 |
1110 |
| 60 |
1150 |
| 120 |
1150 |
“H”-120 Class Divisions
H-120 class divisions are those divisions formed by decks and bulkheads which comply with the following:
- They shall be constructed of steel or other equivalent material;
- They shall be suitably stiffened;
- They shall be so constructed as to be capable of preventing the passage of smoke and flame after 120 minutes exposure to a hydrocarbon fire test;
- They shall be so insulated that, if the designated exposure face(s) is (are) exposed to the hydrocarbon fire test for two hours, the average temperature on the unexposed face will not increase at any time during the test by more than 140°C above the initial temperature nor shall the temperature at any point of the face, including any joint, rise more than 180°C above the initial temperature within two hours;
- Structures intended to be load bearing should either be tested under representative conditions of loading and restraint or have the temperature of the load bearing medium monitored during the test to demonstrate that the maximum temperature attained would not have resulted in loss of strength or stiffness or excessive expansion such as to impair the load bearing capacity.
“H”-60 Class Divisions
H-60 class divisions are those divisions formed by decks and bulkheads which comply with the following:
- They shall be constructed of steel or other equivalent material;
- They shall be suitably stiffened;
- They shall be so constructed as to be capable of preventing the passage of smoke and flame after 120 minutes exposure to a hydrocarbon fire test;
- They shall be so insulated that, if the designated exposure face(s) is(are) exposed to the hydrocarbon fire test for one hour, the average temperature on the unexposed face will not increase at any time during the test by more than 140°C above the initial temperature nor shall the temperature at any point on the face, including any joint, rise more than 180°C above the initial temperature within one hour;
- Structures intended to be load bearing should either be tested under representative conditions of loading and restraint or have the temperature of the load bearing medium monitored during the test to demonstrate that the maximum temperature attained would not have resulted in loss of strength or stiffness or excessive expansion such as to impair the load bearing capacity.
“H”-0 Class Divisions
H-0 class divisions are those divisions formed by decks and bulkheads which comply with the following:
- They shall be constructed of steel or other equivalent material;
- They shall be suitably stiffened;
- They shall be so constructed as to be capable of preventing the passage of smoke and flame after 120 minutes exposure to a hydrocarbon fire test;
- Structures intended to be load bearing should either be tested under representative conditions of loading and restraint or have the temperature of the load bearing medium monitored during the test to demonstrate that the maximum temperature attained would not have resulted in loss of strength or stiffness or excessive expansion such as to impair the load bearing capacity.
Jet Fire Class Divisions
Jet fire class divisions are those divisions formed by decks and bulkheads which comply with the following:
- They shall be constructed of steel or equivalent material;
- They shall be suitably stiffened;
- They shall be so constructed as to be capable of preventing the passage of smoke and flame after a defined period in minutes exposure to a recognized jet fire test;
- They shall be so insulated that if the designed exposure face(s) is (are) exposed to the defined jet fire test for the defined period of minutes, the temperature on the unexposed face will not increase at any time during the test by more than 140°C above the initial temperature, nor shall the temperature at any point on the face, including any joint, rise more than 180°C above the initial temperature within the defined period of time.
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