How to choose the thickness of fire protection mortar?
The safety of people and property in the event of a fire depends on the appropriate selection of the thickness of the fire protection used to suit the type of construction material. The thickness of the sprayed mortar determines the type of element to be fire-protected, as well as the material from which the element is made. So how to properly design passive fire protection of a building structure in the form of a fire retardant mortar?
Protection of steel elements
Fire protection for structures is a barrier that causes the element to heat up more slowly, so that in fire conditions it can perform load-bearing functions for a longer time. The minimum thickness of the fireproof material is selected depending on the type of fire, the fire resistance class of the structure and the critical temperature. Additionally, it depends on the massiveness of the element (exposure to fire conditions).
The minimum thicknesses of fire-retardant insulation of steel structure elements made with fire-retardant mortars, depending on the cross-section exposure index and the critical temperature of the steel, ensuring fire resistance within 30, 60, 120, 240 minutes in cellulosic or hydrocarbon fire conditions are presented in the appropriate tables included in the documents allowing spraying for sale, such as the National Technical Assessment or the European Technical Assessment.
An example of a table specifying the spray thickness on open profiles for a hydrocarbon fire, included in the National Technical Assessment.
|
Fire resistance time – 120 min – hydrocarbon fire – open profiles |
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|
Temperature [°C] |
350 |
400 |
450 |
500 |
550 |
600 |
650 |
700 |
|
Section exposure index |
|
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|
≤ 64 |
37,5 |
33,0 |
29,0 |
26,0 |
23,0 |
21,0 |
19,0 |
17,0 |
|
70 |
38,0 |
34,0 |
30,5 |
27,0 |
24,5 |
22,5 |
20,5 |
18,5 |
|
80 |
39,0 |
35,0 |
32,0 |
29,0 |
26,5 |
24,5 |
22,5 |
21,0 |
|
90 |
39,5 |
36,0 |
33,0 |
30,5 |
28,0 |
26,0 |
24,5 |
22,5 |
|
100 |
40,0 |
36,5 |
34,0 |
31,5 |
29,0 |
27,5 |
25,5 |
24,0 |
|
110 |
40,0 |
37,0 |
34,5 |
32,0 |
30,0 |
28,5 |
26,5 |
25,0 |
|
120 |
40,5 |
37,5 |
35,0 |
33,0 |
31,0 |
29,0 |
27,5 |
26,0 |
|
130 |
40,5 |
38,0 |
35,5 |
33,5 |
31,5 |
30,0 |
28,5 |
27,0 |
|
140 |
41,0 |
38,0 |
36,0 |
34,0 |
32,0 |
30,5 |
29,0 |
27,5 |
|
150 |
41,0 |
38,5 |
36,5 |
34,5 |
32,5 |
31,0 |
29,5 |
28,5 |
|
160 |
41,0 |
38,5 |
36,5 |
34,5 |
33,0 |
31,5 |
30,0 |
29,0 |
|
170 |
41,0 |
39,0 |
37,0 |
35,0 |
33,5 |
32,0 |
30,5 |
29,5 |
|
180 |
41,5 |
39,0 |
37,0 |
35,5 |
33,5 |
32,0 |
31,0 |
29,5 |
|
190 |
41,5 |
39,5 |
37,5 |
35,5 |
34,0 |
32,5 |
31,5 |
30,0 |
|
200 |
41,5 |
39,5 |
37,5 |
36,0 |
34,5 |
33,0 |
31,5 |
30,5 |
|
210 |
41,5 |
39,5 |
37,5 |
36,0 |
34,5 |
33,0 |
32,0 |
30,5 |
|
220 |
41,5 |
39,5 |
38,0 |
36,0 |
34,5 |
33,5 |
32,0 |
31,0 |
|
230 |
41,5 |
39,5 |
38,0 |
36,5 |
35,0 |
33,5 |
32,5 |
31,0 |
|
240 |
42,0 |
40,0 |
38,0 |
36,5 |
35,0 |
34,0 |
32,5 |
31,5 |
|
250 |
42,0 |
40,0 |
38,0 |
36,5 |
35,0 |
34,0 |
33,0 |
31,5 |
|
260 |
42,0 |
40,0 |
38,5 |
37,0 |
35,5 |
34,0 |
33,0 |
32,0 |
|
270 |
42,0 |
40,0 |
38,5 |
37,0 |
35,5 |
34,5 |
33,0 |
32,0 |
|
280 |
42,0 |
40,0 |
38,5 |
37,0 |
35,5 |
34,5 |
33,5 |
32,0 |
|
290 |
42,0 |
40,0 |
38,5 |
37,0 |
36,0 |
34,5 |
33,5 |
32,5 |
|
300 |
42,0 |
40,5 |
38,5 |
37,0 |
36,0 |
34,5 |
33,5 |
32,5 |
|
310 |
42,0 |
40,5 |
38,5 |
37,5 |
36,0 |
35,0 |
33,5 |
32,5 |
|
320 |
42,0 |
40,5 |
39,0 |
37,5 |
36,0 |
35,0 |
34,0 |
33,0 |
|
330 |
42,0 |
40,5 |
39,0 |
37,5 |
36,0 |
35,0 |
34,0 |
33,0 |
|
340 |
42,0 |
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