Algemeen
De levenscyclus van PVC en
alternatieven vergeleken
Iedereen speelt een beetje vals... (engels)
Grondstof en energieverbruik van PVC en alternatieven (engels)
PVC en alternatieven in productie (engels)
PVC en alternatieven in gebruik (engels)
De alternatieven (engels)
Conclusie (engels)
Volledige levenscyclus van PVC en
alternatieven in verschillende toepassingen
PVC en additieven
The industry, the government, the environmental groups: everybody
has some interest to hide some facts at one side, or to exxagerate
the same facts at the other side.
If you look e.g. to one of the first Life Cycle Analyses (LCA's) made by the Swiss
Government on different materials, one can see that the Government
protects the own Swiss aluminium industry, by accounting the
pollution of electricity production only to Swiss (mainly) water
power, while the other materials are accounted for a European mix
electricity (fossil fuels, nuclear- and waterpower).
Also, when industry orders for an LCA, comparing their materials
against other manufacturers' ones, you should be aware that they
want the scientists to emphasise on the good sides of their
products and on the bad sides of the competitors' one.
On the other hand, a peer
review of an LCA on PVC-, PET- and glass bottles for
mineral water in Belgium used figures for dioxin emissions of
PVC-plants suggested by... Greenpeace, which were 10,000 times
higher than the real values found by universities and
investigators of the Government. That is no wonder, if you know
that the not so independent reviewers were acting against the use
of PVC since many years...
There are still other drawbacks on LCA's. An LCA is a
investigation of a certain moment and can be outdated rapidely,
because of investments in the factories. So are e.g. the emission
of dioxins and other chlorinated compounds from PVC factories to
water reduced by a hundredfold in the past ten years, just by
introducing (biological) waste water treatments. The same is true
for air emissions.
Another problem can be that the differences in emissions between
factories, making the same products, can differ widely, where the
difference can be much wider than between factories making
different products. In that case, factories which have invested a
lot in reducing emissions are punished, because other ones didn't
do that. In fact, average emissions for one type of product should
be accompanied with lowest and highest measured values and with
the possible lows when the Best Available Technology (BAT) should
have been used.
Let us look at an overview of the energy use of different materials, presented by an environmental group (acting against the use of PVC!), based on figures from a scientific institute in The Netherlands. The figures for the use of crude oil - as raw material - were calculated by myself. If you have better ones, don't hesitate to send them to me...
Energy and crude oil use for different materials.
All figures as GJ/ton for energy use and ton/ton for crude oil.
| Energy and crude oil use for different materials |
||
|---|---|---|
| Material | energy use |
crude oil use |
| PVC | 53 | 0.63 |
| LD/HDPE | 70 | 1.10 |
| PP | 73 | 1.17 |
| PS | 80 | 1.26 |
| PET | 84 | 1.65 |
| PC | 107 | 1.68 |
| Steel | 30 | 0.00 |
| Aluminium | 200 | 0.00 |
As you can see, the energy and crude oil use of PVC is the lowest
of all plastics. Not bad for an energy guttler, isn't it?
Steel and aluminium don't use crude oil as raw material, but steel
needs coal and aluminium uses also coal and lots of electrical
energy. The amount of crude oil should not be overemphasised, all
plastics in the world do use only 4% of all crude oil, 94% is
directly used for energy, the rest for other purposes. So, if
crude oil should only be used for making plastics, it would be an
abundant material...
It is quite normal that the energy and crude oil use of PVC is the lowest, because 57% of PVC comes from salt, an extremely abundant material on earth. Of course you need energy to split salt into chlorine and sodiumhydroxyde, but in many cases this is done by combined heat/energy power plants with very high yield on energy and you have two valuable products for the same energy. Sometimes you even have three products: chlorine is first used to make another product, like polycarbonate (PC) or polyurethane (PU), before it is used to make DCE/VCM/PVC. That means that in such cases the energy use of PVC and of the other products is even lower.
The energy use per ton is not the only point in total energy use during a lifetime: the amount of material, needed for a certain application, the type of use and the length of a usefull life is important too. Although aluminium needs much more energy for production, it saves much more energy when used for e.g. making car motors, because of the lighter weight. That means that you need less aluminium in weight to make the same motor and lighter cars, which gives less petrol consumption, thus energy (and pollution) savings during lifetime.
Critical volumes for the production of different materials.
All figures in m3 air/kg and dm3 water/kg.
| Critical volumes for the production of different materials. |
||
|---|---|---|
| Material | c.v. air | c.v. water |
| PVC | 700 | 3,000 |
| LDPE | 265 | 1,650 |
| PP/HDPE | 325 | 3,685 |
| PS | 255 | 6,335 |
| PET | 180 | 8,000 |
| PC | 180 | 5,050 |
| Steel | 3,400 | 4,600 |
| Aluminium | 9,320 | 27,700 |
These figures are in fact not complete and outdated.
Not complete, because the energy emissions were not included. Why,
that was not clear, until we saw the difference: electrical power
for salt-chlorine-PVC plants is mainly produced by the use of
natural gas, while most refinaries use their own waste. This gives
for the biggest refinary in The Netherlands already 1,200 tonnes
of soot per year for a work up of 21 million tonnes of crude oil.
As you know the difference in carcinogenity (and persistence!)
between soot and the most important polluters from a PVC factory:
VCM and DCE (see Chlorine and
cancer), taking into account the energy production would
give a lot more air pollution for the 100% oil based products!
Also outdated, because the DCE-VCM-PVC factories in The
Netherlands since 1991 have installed a lot of new equipment to
reduce the air emissions of DCE with a tenfold and of VCM with a
fivefold, while not much changed at the biggest refinary...
Of course, here too it is important, how much material you need
for a certain application and for some applications more important
(e.g. aluminium and plastics in cars), how much - or less -
pollution is coming from the use of these products.
Al together, the figures for PVC are not so bad for an
environmental poison, isn't it?
PVC is a very versatile material, it is used in tenthousands of
applications, so it is nearly impossible to give a complete
comparison for all these applications.
Rigid PVC is used as building material in window frames, waste
water pipes, etc..., etc... It doesn't rust nor rot and it has a
very long lifespan. PVC drinking water supplies were tested after
37 years underground: No difference was found, compared with new
pipes. So, for this application it will have a lifetime of more
than a hundred years.
Soft PVC sheet can be applicated to strenghten the dikes in The
Netherlands at a much lower price, at much higher speed and with a
four times longer lifespan - up to 200 years - than steel
reinforcements. Electrical cables, isolated with PVC can withstand
sunlight and all outside weather conditions for tens of years,
while the alternatives had to be renewed after eight years,
because of dangerous short circuits in rain, caused by cracked
polymers. So we can go on for many lines...
Of course, all good properties can turn into bad, if that is on
behalf of the environment. We have seen no big problems for PVC
when produced, there are even less when in use. PVC needs
practically no maintenance. This was one of the reasons for the
Gothenburg (Sweden) hospitals to choose for vinyl instead of
linoleum floorings. Although the production of linoleum uses near
only renewable raw materials (linseed oil), it is less favorable
in use: before the application of vinyl they had to use 6 tons of
cleaning agents per year, after that, 0.5 tons and they will
reduce it to near zero.
The same is thrue for wooden window frames: Wood is a 100%
renewable raw material, but, besides production emissions (2/3 of
the wood ends as production waste, which is mainly burned!),
wooden window frames have to be painted, or treated. This makes
the use of wood and PVC for window frames equally good (or bad)
for the environment.
PVC was accused to have many negative aspects for health and
environment. In all cases these accusations turned out to be
false.
PVC softeners, like phtalates, are linked to cancer and
oestrogenic properties. That may be the case, if you give massive
doses to rats - up to an equivalent of 500 g/day for an adult
human - but after hundreds of tests, not for primates (apes and
humans), because differences in metabolism. PVC, including
phtalates, is the only thoroughly tested plastic which is
permitted for bloodbags. In fact, you ingest near 0.1 g of
phtalates per year by using PVC, the toxic equivalent of drinking
0.01 g of alkohol... per year.
PVC was accused to give remaining VCM in food and water, which can
cause cancer, it turned out that water from PVC-bottles gives (an
insignificant) 1.9% less cancer, compared with water from
glass bottles in a mega-experiment.
PVC was accused to be the origin of sudden childrens dead, it
turned out to be the contrary: one of the many possible causes is
the use of matrasses which catch a lot of dust. PVC and other
plastic layers prevent that.
PVC was accused to give irritations and allergic reactions, it
turned out to be the contrary: a lot of hospitals, especially
build for allergy patients are using PVC as building material,
because a lot of natural materials like certain types of wood and
not well treated natural rubber (latex) can give severe allergic
reactions.
So we can go on... It is easy to find new allegations every day,
so you can accuse anything to be an 'environmental poison',
because it takes months, even years to prove that the allegation
was false. The general public in the meantime will remember only
the allegation which was widespread in newspapers and other media.
The positive results, months or years later, are in general not
even mentioned, or somewere on the twentieth page...
All alternatives for PVC, give pollution during production, transport, recycling and/or incineration. In many cases, they use more energy and more scarce raw materials than PVC and in many cases they give more important air and water emissions than the production, transport, use, recycling, incineration and accidental fires of PVC.
There is no reason to threat the environmental impact from PVC in its whole lifecycle different from the alternatives. And there are no reasons at all to ask for a ban on PVC, only some minor for a change-over to alternatives. But there are at least as much reasons for a change-over from the alternatives to PVC.
You are at level two of the Chlorophiles pages
Created: 16 March, 1996.
Last update: 18 September, 2001.
Final update: 31 March, 2019
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