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One of the most important considerations when installing fire dampers is their compatibility with the wall or floor construction they're being installed into, the size of the opening, and the type of penetration seal. Over this two-part blog, we will look at how supporting constructions are defined with respect to fire dampers, and then we will look at some of the problems that can occur on site.
Types of Supporting Constructions
Supporting constructions for fire dampers are defined within EN 1363-1:2020 'General Requirements for Fire Resistance Tests'. For walls, these comprise of standard supporting constructions (either flexible or rigid) and non-standard supporting constructions. Standard Floors are covered in EN1366-2:2015 rather than EN1363-1:2020.
Standard Supporting Constructions
A Standard Supporting construction is defined as:
"Forms of construction which have a quantifiable influence on the heat transfer between the construction and the test specimen and which provide known resistance to thermally induced distortion".
Types of Standard Supporting Constructions
Standard Rigid Supporting Constructions
Rigid supporting construction is split into high and low-density groups.
High-density rigid constructions have an overall density greater than or equal to 850kg/m3 at an appropriate thickness. Examples of this could include a masonry or homogenous concrete wall.
Low-density rigid construction is an aerated concrete block wall with an overall density of 650+/- 200 kg/m3, at an appropriate thickness.
Standard Flexible Supporting Constructions
This is a lightweight plasterboard faced steel partition constructed in accordance with the table given below. This table is taken from EN1363-1:2020.
|
Intended fire resistance |
Nominal steel stud depth [mm] |
Gypsum boards type F, EN 520 |
Insulation: mineral wool |
||||
|
|
Group A |
Group B |
Group C |
number of layers at each side |
thickness of boards [mm] |
thickness [mm] |
density [kg/m3] |
|
EI 30 |
44 to 55 |
56 to 75 |
76 to 100 |
1 |
12,5 |
40 to 50 |
30 to 60 |
|
EI 60 |
44 to 55 |
56 to 75 |
76 to 100 |
2 |
12,5 |
40 to 50 |
30 to 60 |
|
EI 90 |
44 to 55 |
56 to 75 |
76 to 100 |
2 |
12,5 |
40 to 50 |
85 to 115 |
|
EI 120 |
62 to 70 |
71 to 75 |
76 to 100 |
2 |
15 |
60 to 70 |
85 to 115 |
In order to meet the requirements described above, the stud work must be steel and not timber. If the wall is tested with insulation as specified in the table above, then it also covers you for a wall that is non insulated. If the test is conducted without insulation in the wall, then it is only applicable to walls that are uninsulated. Both these rules are specified in the Direct Field of Application in EN1366-2:2015.
Standard Floor Constructions
Standard floor construction consists of either Aerated Concrete or Normal Concrete. The thickness, density and test duration are detailed in the table below.
|
Type of construction |
Thickness mm |
Density kg/m3 |
Test duration t h |
|
Normal concrete |
110 ± 10 |
2 200 ± 200 |
t ≤ 1,5 |
|
150 ± 10 |
2 200 ± 200 |
1,5 < t ≤ 3 |
|
|
175 ± 10 |
2 200 ± 200 |
3 < t ≤ 4 |
|
|
Aerated concrete |
125 ± 10 |
650 ± 200 |
t ≤ 2 |
|
150 ± 10 |
650 ± 200 |
2 < t ≤ 4 |
Non-Standard Supporting Constructions
These are defined as specific construction in which the test specimen is to be installed in practice and which are not already covered by standard supporting constructions.
They have a more restrictive direct field of application than a standard supporting construction because the influence on the heat transfer between the construction and the damper and the resistance to thermally induced distortion is not known.
Examples of specific supporting construction would include asymmetric flexible wall systems (referred to as shaft walls in the UK), composite wall systems (sometimes called 'white wall'), Cross Laminated Timber (CLT) and Structural Insulated Panels (SIPS).
Any testing done on these specific supporting constructions is limited to the manufacturer and systems tested. For example, the test results from a flexible 'shaft wall' system made by manufacturer A do not apply to an equivalent system made by manufacturer B.
Summary
- Supporting constructions are either defined as standard or non-standard (specific).
- Standard supporting constructions are clearly defined in the relevant standards for dampers. Keep in mind that there are some subtle differences between standard supporting construction for dampers and other penetration seals.
- Specific supporting constructions are manufacture specific.
In the next part of this blog, we will look at some of the most common challenges that we see when people are installing dampers with supporting construction.
