Civil Engineering Reference
In-Depth Information
Table 9.10:
Plastics and fire
Type of plastic
Gas emitted when burnt
Polyvinyl chloride (PVC)
CO, CO
2
, CH
4
, HCl, Ba, Cd
Unsaturated polyester (UP)
CO, CO
2
, benzene, styrene, formaldehyde
Polyurethane (PUR)
CO, CO
2
, benzo nitrile, acetonitrile, ammonia, prussic acid, NO
x
Polystyrene (PS)
CO, CO
2
, benzene, styrene, formaldehyde
Chloroprene rubber (CR)
HCl, dioxines
Butadiene styrene rubber (SBR)
SO
x
, NO
x
Note:
When using halogenic fire retardants and chlorinated paraffins, dioxines can be formed
of windows) and flame retardants with chloroparaffins and antimony trioxide. In
PVC gutters, cables and pipes lead is often used as the ultraviolet stabilizer.
There are likely to be emissions from production plants of chlorine gas, ethyl-
ene, dioxin, vinyl chloride, the solvent dichloretane, mercury and other damag-
ing substances. Certain larger plastics works have emissions of tons of phthalate
into the air every year. During production, workers can be exposed to organic
acidic anhydrides.
Emissions of phthalates or organic acidic anhydrides (when heated) can occur
from the completed product and within the building, together with a series of
other volatile substances such as aliphatic and aromatic hydrocarbons, phenols,
aldehydes and ketanes, though only in small amounts. Left-over monomers from
vinyl chloride may also be released (approximately 10 mg/kg PVC). There is also
greater microbiological growth in plastic with phthalates, which probably func-
tions as a source of carbon and nitrogen.
As a waste product, PVC contains environmentally dangerous substances that can
seep out, e.g. when heavy metals have been used as pigments or cadmium as an ultra-
violet stabilizer. PVC is considered to be the largest source of chlorine in waste prod-
ucts. When burnt it can form concentrated hydrochloric acid and dioxin. PVC waste
can form hydrogen chloride when exposed to solar radiation. It decomposes slowly.
Durability of plastic products
Many external factors can break down plastics: ultraviolet and visible light, heat,
cold, mechanical stress, wind, snow, hail, ice, acids, ozone and other air pollu-
tants, water and other liquids, micro-organisms, animals and plants. The life-
span of a plastic depends on its type, its position and the local climate.
Plastic products are used in floors, roofs and walls in such a way that it is dif-
ficult and expensive to repair or replace them. They should have a functional life-
span equivalent to other materials in the building - at least 50 years. It is unlike-
ly that any of today's plastics can satisfy such conditions.
