spontaneous tempered glass breakage on greenhouse
spontaneous tempered glass breakage on greenhouse
(OP)
I was wondering whether there is someone who can do some analysis or forensic study of glass breaking on a greenhouse. There are about 3000 individual lites on this structure and there is spontaneous glass breaking in January/February/March time frame every year. The breakage usually happens mid morning after a cold night and the next morning is very sunny and bright. The glazing system is tempered glass in a lapped configuration (like shingles) and an aluminum bar with stainless steel glass clips holding the glass down.
thank you
thank you
RE: spontaneous tempered glass breakage on greenhouse
It seems to me that the glass which is breaking up is due to the thermal shock.Cold in night and hot in morning.Glass is by nature insulator. It takes time to heat up and release the heat so as to cool down.A toughned glass will be more prone to thermal shock breakages. Toughned glasses are good for resisting mechanical shocks.Try a glass with lower alpha value. i.e,a glass having low dilatometric coefficient value. Since I do not know the detailed data. I would prefer not to comment on the value of alpha that you should go for.
Regards
Shudipto
RE: spontaneous tempered glass breakage on greenhouse
RE: spontaneous tempered glass breakage on greenhouse
RE: spontaneous tempered glass breakage on greenhouse
Thank you again
Oolitic
RE: spontaneous tempered glass breakage on greenhouse
Take a good look at the greenhouse. It may help if the structure is straitened out.
Kees Douma
Caravell Engineering Design
RE: spontaneous tempered glass breakage on greenhouse
Another possibility is breakage caused by nickel sulfide inclusions. NiS induced fractures often occur during cold weather when direct solar beam radiation strikes the glass.
Our consulting group does failure analysis on glass and glazing systems, but I am not sure that a greenhouse application would bear the costs.
NiS inclusions look like tiny spheres (barely visible with a magnifying glass) in 13mm glass. In 6mm material, they are egg-shaped. In 3mm glass, they are cigar-shaped. The shape varies with thickness because a float glass line is a constant-volume system. A thin raw glass ribbon is pulled through the aperture (drawn) more than a thick one.
If neither of these causes prove to be the cause breakage in the case you mentioned, I would have to know more about the specific glazing system to be of any help.