Thermal movement
Thermal movement
Titanium zinc has a relatively large linear expansion coefficient: 0.022 mm/(m.K)
To date the literature still refers to the expansion of zinc, although thermal movement is more appropriate. The material will after all expand and contract.
Example: a gutter with a length of 8 metres is applied at room temperature (15°C). The T equals 100 K. The maximum expansion in summertime is 11.44 mm. The maximum contraction in wintertime is 6.16 mm. The total thermal movement for this gutter is 17.6 mm.
The total thermal movement should not exceed 20 mm. If the thermal movement is larger than 20 mm an expansion device must be used.
Expansion
Expansion devices are necessary in order to absorb the expansion and contraction of the material. When developing a roof covering or wall cladding thermal movement and expansion should always be considered, because of the relatively large linear expansion coefficient.
When gutters are applied, a rubber expansion can be used. It is also possible to use a zinc expansion device consisting of expansion sleeves and a separation slide fully made of zinc.
Tabel: Expansion device in roof gutter
Gutters provided with bead 20 mm and material thickness 0.80 mm
(Girth 300 mm in 700 mm)
gutter
construction |
Max. gutterlength
in metres without
expansion-sleeve |
Max. distance
in metres between
2 expansion devices |
|
|
Developed width of the
gutter < 550mm |
Developed width of the
gutter > 550mm |
gutter in the box |
|
mechanical expansion |
rubber expansion |
mechanical expansion |
rubber expansion |
2 free ends **** |
12 |
12 |
9 |
9 |
6 |
1 free end **** |
6 |
6 |
4,5 |
4,5 |
3 |
gutter in the bracket |
|
|
|
|
|
2 free ends *** |
18 |
18 |
12 |
12 |
9 |
1 free end *** |
9 |
9 |
6 |
6 |
4,5 |
*** The free expansion space must be at least 10-15 mm
**** The free expansion space must be at least 20 mm