Glass Flashcards
Uses of glass?
Solar gain/ radiation
reduced need for lighting
impression of space / common on underground entrances or busy building entrances
raw materials required for glass?
Silica 60%
limestone 18%
soda ash 18%
other minor constituents 4%
how energy intesive is glass?
very, around 35% of cost is from energy
what does amorphous mean for glass?
it doesnt have a crystaline structure or grain and can be considered on huge molcule
lack of grain and crystal structure give it transparency
how is glass manufactured?
molten glass 1000c is poured onto the surface of a motlen bath of tin,
bubbles float up, impurities fall to the bottem and the glass levels out forms a constant surface over 2 days
the glass is then drawn out of the bath onto rollers at about 550c at a thickness between 0.5-25mm
widths up to 3m
surface coatings can then be added
glass is cooled at a controlled rate to relieve internal stress
checked for defects
and cut to size
what is strengthend glass
its glass that has been partially toughend/ semi tempered
slowely annealed then cooled
surface cools and contracts quickly
core stays soft and cools slowly pulling the surface into compression
twice as strong as regular glass
will shard
what is thermolly toughened glass?
fully tempered saftey glass
similar to semi tempered however cool much faster
is twice as strong again
surface in compression
center in tension
small pieces
what is laminated glass?
two or more layers of glass bonded by sheets of clear plastic
plastic keeps broken glass in one place
bullet proof glass
what is self cleaning glass?
thin layer of titanium dioxide on it
causes uv to break up dirty
rain spreads evenly leaving no streaks
how much heat is lost through windows?
Assuming 20% of wall space is glazed and walls unisulated
a 10% loss can be expected
this rises as everything is insulated
what is 2 tripple glazed window equivalent to?
5 single glazed windows or 3 double
potentially with low e coating, spacing and gas filled can be the equivalent to 1 tripple
what is low emissive coating for?
to reflect radiation back into the building
can hardened glass be cut?
no
