[HN Gopher] Kenyan recycles plastic waste into bricks stronger t...
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Kenyan recycles plastic waste into bricks stronger than concrete
Author : elorant
Score : 204 points
Date : 2021-02-10 19:26 UTC (3 hours ago)
(HTM) web link (www.reuters.com)
(TXT) w3m dump (www.reuters.com)
| [deleted]
| foofoo55 wrote:
| Interesting she doesn't work with PET.
|
| I wonder what happens to the waste from deburring and
| installation, and the microplastic dust from cutting and wear &
| tear.
|
| I sometimes feel the only option for waste plastic is
| incineration.
| warent wrote:
| Incineration would probably be much, much worse, because all
| you're doing is releasing toxic pollutants into the
| air/atmosphere
|
| Unless you're talking about plasma gasification, in which case
| I wholeheartedly agree it appears to be a very promising
| solution, and wish I had resources to invest in that.
| samatman wrote:
| Plasma gasification is overkill, obtaining complete
| combustion is a matter of reaching sufficient heat and mixing
| adequate oxygen, that, and not allowing particles to escape
| before combustion is complete.
|
| Basically, the difference between a fireplace and a rocket
| stove.
|
| There are plenty of ways to construct an incinerator which
| does this, it's a fairly mature technology.
| toomuchtodo wrote:
| I too would love to work in the plasma gasification space,
| but it doesn't seem like there's a lot of interest in
| investment in that area even with the waste to energy and
| environment benefit potential.
|
| We could have self powered ocean platforms collecting and
| plasma gasifying plastic waste, instead of dragging all of
| that waste back to land for processing.
| warent wrote:
| I've been dreaming about this for years. Most people who
| hear about it think it's nonsense. You could even set up
| plants near landfills and deploy little Wall-E robots to
| dig up and transport landfill for syngas. Feeling like
| we'll see this in the next 100 years.
|
| Part of the reason there's little investment is apparently
| because the energy generation is barely above net neutral
| with current technology. Still though, even at neutral it
| seems like it would be good to clean up soil and create
| slag for construction.
|
| It would probably work best as a nonprofit/government
| project
| toomuchtodo wrote:
| Keeping my eye out for natural gas processing ships going
| for a song.
| mediaman wrote:
| PET has a much higher melt temperature, which would degrade the
| HDPE. At HDPE melt temperatures, the PET would remain unmelted,
| which would probably cause strength and visual problems.
| latchkey wrote:
| What about leaching chemicals into the soil and groundwater?
| adambcn wrote:
| Stronger how? Torsional strength? Compression strength? Tension
| strength? Hardness? Yield strength?
|
| Or just random person throwing it on the floor?
| Triv888 wrote:
| "Does not crack" doesn't mean that it is stronger at what
| concrete is good for. Try to build a 70 story building with that
| stuff, for example. Diamond is good for scratching, steel can be
| good for hitting....
| scythe wrote:
| The world produces four billion tons of cement per year, about
| half of which is produced in China. For comparison, polyethylene,
| used for these bricks, is produced at about 100 million tons per
| year.
|
| In other words, even if all of the waste polyethylene in the
| world could be recycled like this, it would make, at best, a
| roughly 2.5% dent in the demand for concrete. (There are
| aggregates in both cases, so you can't just lean on that.)
|
| It's useful if it offers functionality cement doesn't have, which
| in this case it seems to. But the idea that plastic waste, in any
| form, or for that matter any other wastes (aside from asphalt,
| which was once a waste product), can substantially replace
| building materials, is mostly a popular misconception rooted in
| humans' difficulty with large numbers. Comparing the bricks to
| concrete just isn't really apples-to-apples.
| why_Mr_Anderson wrote:
| Not to mention there are so many different types of concrete
| tailored to meet specific requirements that it's very unlikely
| _anything_ could even make a dent in our need for concrete.
| ggm wrote:
| There is a role for fibre as a reinforce in cast concrete. It's
| well known from bricks with straw. Alters the strength under
| load, strength to weight. Has a role in post earthquake
| survivability rates.
|
| Is it magic? No. There is no magic. But, its possibly useful,
| depending how its formed and how it's used and incorporated
| balozi wrote:
| I hope this is not laying the groundwork for developed nations to
| ship their plastic waste to Africa. China won't take the waste
| anymore so now we ship it to Kenya, to make paving bricks.
| plosticks wrote:
| Polyethylene is a wonderful material for subtractive
| manufacturing, especially parts that you might otherwise 3D-print
| or make out of wood.
|
| It's easy to make "bricks" by melting and pressing chips and
| shredded material in a mold, and those bricks make excellent
| machine stock.
|
| You can't use it as a building material, but I like the idea of
| mixing in sand and using them as paving stones. After all, we
| frequently pave playgrounds with flammable material made out of
| shredded tires.
|
| I do wonder about microplastics flaking off of them, though. PE
| is pretty remeltable, but like most plastics it gets a bit more
| brittle with every cycle. Most recycling outfits mix some virgin
| plastics in with the recycled stuff for that reason.
| trhway wrote:
| >I do wonder about microplastics flaking off of them
|
| especially under strong light/UV of equatorial Sun. While the
| story looks great at first, i wonder whether it can succeed
| under more strong environmental review.
| dylan604 wrote:
| The article says the factory has been running since 2017.
| That's going on 4 years of stuff from the factory being in
| the sun. I have seen plastic items last less than one Texas
| summer in the sun. Either they've done a brilliant PR
| campaign to keep the "sun kills this product" stories, or it
| is less of an issue than HN wants it to be.
| bluGill wrote:
| There are UV inhibitors that are added to plastic. They
| give you more time in the sun, though eventually you are
| done.
| why_Mr_Anderson wrote:
| _After all, we frequently pave playgrounds with fl\ammable
| material made out of shredded tires._ Wait,really? Could you
| point me to some material about it? I know it was tried several
| times in many countries but IIRC everyone returned to just pure
| alsphalt, but I don 't remember what was the actual reason.
| anonAndOn wrote:
| Rubber covered playgrounds are considered safer for falls.[0]
| However, it's not just for kids, recycled substrates for
| athletic facilities are very popular. This shoe manufacturer
| recycles some of its products just for that purpose.[1]
|
| [0]https://www.calrecycle.ca.gov/Tires/Products/Types/Playgro
| un... [1]https://www.nikegrind.com/
| ttul wrote:
| She should do YC.
| ummonk wrote:
| What happens when these erode - wouldn't plastic particles
| contaminate water?
| lmilcin wrote:
| Just because the brick is able to withstand throwing it on the
| rocks doesn't mean it is not going to deform under load.
|
| Brick strength is measured in ability to withstand deformation
| under load and as far as I know there isn't any popular "plastic"
| that can do comparably.
|
| For a single story house this probably doesn't make any
| difference, but for a larger structure the load could cause
| bricks to loose shape, creep and cause the structure to fail.
|
| Also, plastics tend to get soft rapidly at temperatures. I don't
| think plastic bricks exposed to sun (Kenya?) would fare for long.
|
| Another issue is that plastics tend to deteriorate in UV. That
| could be fixed with a good paint but it also costs.
|
| (Edit: for the pavement this is horrible idea as the plastic is
| going to be broken down and dispersed in environment in large
| amounts)
| jay_kyburz wrote:
| I only skimmed the article, but I thought they were just
| pavers. (For making a path).
|
| Buy yes, I came to say something similar, if you just compress
| the plastic into a block and lay it down to make a path then as
| it deteriorates surly you are just contaminating your
| environment with mico-plastic particles.
| londons_explore wrote:
| Ssssh...
|
| People prefer to distribute their problem into invisible
| pieces put into the environment slowly over 1000 years than
| to just bite the bullet and incinerate plastics that have
| reached their usable lifespan...
| smeyer wrote:
| There are real reasons to not want microplastics in your
| local environment, but I think your dismissiveness of
| spreading a problem out over 1,000 years is unwarranted.
| There is a huge difference between a problem that has to be
| solved in a year and a problem that has to be solved in 100
| or 1,000 years, because time is an incredibly valuable
| asset.
|
| Delaying some of the carbon we put in the atmosphere for
| hundreds of years is massively useful, because it buys us
| time to try stave off and ameliorate some of the effects of
| climate change.
| vlovich123 wrote:
| Sure, the climate change problem is eased. Microplastics
| in the environment though are a totally different problem
| & having it slowly accumulate over thousands of years is
| actually worse because it's a tragedy of the commons
| scenario. Cleaning this up in 100 years is going to be
| far more expensive than forcing companies to deal with
| the trash properly now. Moreover, it's not the companies
| that end up paying for such a problem but the rest of us
| because they've externalized the problem (see all the
| superfund sites in the USA that are chronically
| underfunded).
| Retric wrote:
| Individual micro plastics don't last that long. The vast
| surface area to volume ratio speeds up how quickly even
| durable plastics break down.
| lmilcin wrote:
| Well, unless you start inhaling the plastic dust from
| plastic road.
|
| I am pretty sure that, even if not "forever chemical",
| the plastic dust _will_ outlive your lungs.
| arcticbull wrote:
| Fair but you can also simply bury the compressed bricks
| yeah? Recycling plastic has always been a ploy by the oil
| industry to increase consumption and make people feel
| good about the product.
|
| Burying the compressed bricks is actually a great way to
| handle sequestration.
|
| [1] https://www.npr.org/2020/09/11/897692090/how-big-oil-
| misled-...
| notjtrig wrote:
| 'The best solution to pollution is dilution'
| robotnikman wrote:
| The microplastics which we don't see always comes to my mind
| when I see plastic reused in ways such as this.
|
| Though it probably does depend on the type of plastic, but
| I'm no chemist.
| Puts wrote:
| Microplastics is a huge problem, BUT I can't imagine this
| being worse than things like tiers and shoe soles.
| lmilcin wrote:
| This is plastic that would go to landfill. Expect it to
| contain just about everything.
|
| I don't expect this to be heavily processed. More like
| melted together with some additions.
| kaycebasques wrote:
| > if you just compress the plastic into a block and lay it
| down to make a path then as it deteriorates surly you are
| just contaminating your environment with mico-plastic
| particles
|
| The article says that the plastic is mixed with sand, heated,
| and then compressed into bricks. Given this, is your comment
| still valid? Honest question, I'm not a material science
| person.
| kaycebasques wrote:
| > Just because the brick is able to withstand throwing it on
| the rocks doesn't mean it is not going to deform under load.
|
| The end of the article says they founded in 2017 and have
| recycled 20 tons of waste. Maybe structural issues will emerge
| after 5+ years of use but it sounds like this approach has
| already had a fair amount of real-world usage.
| robocat wrote:
| You wouldn't use plastic bricks for building without either
| serious fire risks. A non-flammable coating on the brick could
| potentially be developed, but not easily and perhaps not cost
| effectively.
|
| This is what happens when you use polyethylene as part of your
| building: https://www.bbc.com/news/uk-40301289
| labawi wrote:
| The bricks contain polyethylene, but a large part, probably
| most of it, is sand. Also, it is not foam in enclosed spaces,
| but a full hard material.
|
| A non-flammable coating would perhaps be a layer of plaster
| or paint?
|
| I think you are seriously overestimating the flammability of
| the product. Have you seen rooms with vinyl floors, PVC
| windows, foam / fake leather couches? Each of those will burn
| more easily a viciously than the bricks.
|
| My concern would be with possible structural failure at high
| temperatures and some fires may be able to pass through walls
| of these bricks. However, I don't think they are building
| apartment buildings from these bricks.
| dylan604 wrote:
| There are plenty of uses of bricks that do not need to support
| the weight of a multi-story buildings. Just because an item
| doesn't fit for a particular use does not mean it is not a
| viable solution for other things. Paving stones, mailboxes,
| retaining walls, etc are all examples.
|
| I for one can appreciate that someone is taking effort to
| resuse/recycle plastic trash into something useful like this.
| Maybe rather than shitting all over something for a use it's
| not necessarily intended for, maybe try to think of other uses
| this kind of innovative processing can be improved would be
| much more productive.
| butwhywhyoh wrote:
| The title of the post is that these are stronger than
| concrete. The title isn't "these bricks could be used for
| many things". OP is directly responding to a dubious claim.
| Where as you would seem to prefer they ignore the dubious
| claim and just be endlessly positive.
|
| I'd sure as hell rather know if my home is going to collapse
| if I build them out of plastic bricks than someone telling me
| all of the things I could have used them for instead.
| kaycebasques wrote:
| OP did not directly respond to the dubious claim but you
| did. Thank you for reminding me that they're claiming this
| is stronger than concrete. That indeed is dubious. I think
| the conversation is swinging too far in the opposite
| direction, however, and many people seem to be writing this
| off.
| lmilcin wrote:
| Of course there are uses. I am even very happy people try to
| re-use what would normally be put to waste (unless it causes
| more plastic to disperse in environment).
|
| Just don't claim it is "stronger" than regular brick if that
| is not true.
| silicon2401 wrote:
| > Maybe rather than shitting all over something for a use
| it's not necessarily intended for, maybe try to think of
| other uses this kind of innovative processing can be improved
| would be much more productive.
|
| Not a very constructive response. Do you have any
| counterpoints to the other user's points, or do you just not
| allow people to point out potential issues with materials
| that may be used for human housing? Progress requires a
| balance between some people focusing on achievements and some
| pointing out the things that can still be improved. If I were
| going to rely on a new material, I'd definitely want its
| issues to be pointed out and addressed first, rather than
| just jump to using it.
| kristo wrote:
| There is a little thing called tone. And criticizing
| someone's over negativity is constructive.
|
| You'd want that negativity problem to point pointed out and
| addressed, wouldn't you?
| butwhywhyoh wrote:
| I wouldn't. I would rather a world where people are
| strong enough to deal with "tone", which seems to be a
| highly subjective thing. How about giving someone else
| the benefit of the doubt instead of pointing out
| "negativity"?
| [deleted]
| lhorie wrote:
| Not a structural engineer, but I thought that the beams are the
| load bearers, while the bricks are more of less just filling
| vertical space.
|
| I think another interesting point to consider is cost. I
| watched a video a while back about a premise of using plastics
| for building roads, and in addition to the deformation/UV
| deterioration issues being brought up, another issue that was
| brought up was that concrete is cheaper than even the lowest
| quality recycled plastic.
| londons_explore wrote:
| > the load bearers, while the bricks are more of less just
| filling vertical space
|
| Bricks are decorative in a few buildings, but this is by far
| the minority.
|
| Where bricks are used in < 8 floor high buildings, they
| normally are supporting the weight of the entire structure.
| dylan604 wrote:
| Where do you live that a building of modern construction is
| supported by bricks? In the US, multi-story residences are
| built on wood with a brick facade. Multi-story commercial
| buildings are built using wood up to 4 stories (depending
| on locale), and steel after that.
| lmilcin wrote:
| I live in Poland. Almost all buildings outside cities are
| bricks with bricks being load-bearing.
|
| In cities, almost all buildings older than 1950 are also
| made from bricks.
| londons_explore wrote:
| The US is the odd one out... I completely see why you'd
| make a temporary building out of wood so that you can
| build it in just a few days.
|
| But if this is a house, expected to last 150 years plus,
| and you're already bringing lots of bricks to the site,
| you really ought to be using the bricks to hold the
| building up and reserving the wood for the internal
| floors and other things that will be replaced every 75
| years.
| Retric wrote:
| The oldest timber frame house in the US dates to 1637.
|
| Wood easily lasts 200+ years as long as it's thick and
| dry. It tends to sag over time, but most buildings end up
| being fairly temporary on those timescales.
| vbezhenar wrote:
| You can build wooden house that would stand 100+ years.
| Not US-style houses from planks, though, you just cut
| trees and use their trunks as a whole to build walls.
| Also you should protect it from the rotting.
| kube-system wrote:
| There are a very large number of 100+ year old wooden
| homes in the eastern half of the US. Check out Zillow
| with the "year built" filter. Even if you set the filter
| to limit results to 1899 and older, the vast majority of
| homes are of wood construction.
| rootusrootus wrote:
| We don't use bricks for structure any more because
| earthquakes. Wood buildings fare much better when shaken.
| We also have plenty of wooden houses that have stood for
| 150 years.
| AngryData wrote:
| Wood houses can last just as long if they are properly
| built and maintained. I will grant you that many
| buildings in the US aren't built or maintained to last
| that long, but they can and do exist and it is what most
| builders would prefer to build if there was the demand.
| Wood is also much easier to repair if there is damage, or
| easily jacked up if the foundation moves over 100 years.
| bluGill wrote:
| Bricks are not nearly as strong as you intuitively think.
| They do great in compression, but terrible in tension.
| Bricks are also terrible insulation. Real structural
| engineers take this into account, and thus often use wood
| or steel (or other materials) depending on what really
| matters. And of course the entire structure needs to be
| designed as a whole.
| kube-system wrote:
| Wood lasts 150 years plus. There are environmental
| factors that, unmitigated, can damage wood. But the same
| is also the case for masonry construction. They both have
| their pros and cons. And now that things like vinyl
| siding exist, wood homes can last a long time even with
| minimal maintenance.
| syoc wrote:
| A bit off topic but wood houses can, if done right, last
| quite a lot longer than 150 years.
| inglor_cz wrote:
| Central Europe mostly builds from bricks. Not just
| classical red bricks, Ytong is a very popular type too.
|
| Wooden structures copied from Scandinavia are slowly
| coming into fashion for smaller family houses (the
| construction process is very fast compared to bricks),
| but they are still very much in minority.
|
| Taller constructions are concrete + steel.
| doikor wrote:
| > Taller constructions are concrete + steel.
|
| There have been some advancements in wood for taller
| structures in recent years. Basically they have come up
| with wood that is as strong as concrete.
|
| Main problem is fire/pests/rot/etc so you can't build
| crazy big but there are now 7 or 8 story tall apartment
| buildings made out of wood mainly in Helsinki for
| example.
|
| Making apartment buildings out of wood is also much more
| environment friendly then concrete (somewhere around 50%
| less total co2)
| inglor_cz wrote:
| Fennoscandinavians are very good with their wood. (Pun
| not intended.) When other nations try to imitate their
| know-how, the result is usually subpar.
| p_l wrote:
| While sibling comments mentioned a bit about differences
| in building approach with heavy use of brick and concrete
| in Europe, at times it reaches into cultural
| incomprehension.
|
| When US action movies started to show up more in Poland,
| many people joked how american movies exaggerate things
| by using cheap plywood scene sets for houses. Finding out
| that american homes are actually built like that was a
| bit of a shock to many.
| rootusrootus wrote:
| To be fair, a little 4.9 earthquake counts as one of the
| biggest ever recorded in Poland.
| why_Mr_Anderson wrote:
| And if you know anything about electrical wiring, do not
| look up how they do it in those plywood houses in US, any
| European building inspector would have a heart attack :)
| p_l wrote:
| I get shivers just from the standard outlets in USA...
| crazygringo wrote:
| First-world vs third-world (approximately).
|
| In the first world, brick construction is extremely expensive
| and you're right -- modern residences are often built with
| structural beams (whether wood or steel), and the brick is
| usually just a veneer.
|
| But in the third world, variants of brick (e.g. cinder block)
| are often the norm, and are structurally load-bearing, and
| work fine for two to three stories. And they're very easy and
| cheap to build with.
|
| The US has a ton of cheap lumber so load-bearing wood frames
| are common. Many countries don't have forests like that so
| bricks/blocks are the way to go.
| andor wrote:
| I have to disagree, and I don't think the first world vs.
| third world comparison is helpful.
|
| Bricks are quite common in Europe, at least for buildings
| up to a certain height. The resulting buildings here (in
| Germany) offer higher living quality with better thermal
| and acoustic insulation than a typical North American beams
| + drywalls building. That's just an observation though and
| maybe the general construction method is not the cause -
| maybe it's just because our windows and doors are much more
| solid.
| andechs wrote:
| Cinder block construction can also be difficult to insulate
| and hide services such as electricity and plumbing behind.
| In addition, brick buildings are a bad idea in areas
| subject to [seismic
| events](https://www.npr.org/2010/01/14/122547242/haitis-
| buildings-we...).
| lhorie wrote:
| I was under the impression they used metal to reinforce
| masonry, but apparently not all everyone does. Found an
| article that goes into more details and lists pros and cons
| of the masonry approach here:
|
| https://theconstructor.org/construction/masonry/load-
| bearing...
| lmilcin wrote:
| I live in a building where bricks are very much load-bearing.
|
| I have also lived in buildings that had steel or wood beams
| in walls for the purpose of keeping the wall rigid (so that
| it doesn't buckle), but the bricks were still holding most of
| the load.
| why_Mr_Anderson wrote:
| Major problem with plastic in roads is thermal stability and
| abrasion from constant wear. In the end, concrete is not only
| cheaper, but also much safer option.
| gumby wrote:
| > Brick strength is measured in ability to withstand
| deformation under load and as far as I know there isn't any
| popular "plastic" that can do comparably.
|
| By definition something plastic will deform, else it wouldn't
| be plastic! A "rigid plastic" would be like a "miniature giant"
| dogma1138 wrote:
| The plasticity in the name plastic only refers to the
| plasticity during manufacturing which means it can be easily
| shaped or molded.
|
| In their usable form plastics have varying modes of failure
| many of them do not deform at all but shatter just like
| glass.
| solarkraft wrote:
| The talk about it mainly being used on path ways means it's
| especially exposed to the environment, making me concerned about
| plastic particulate being released. Some research on the topic
| would be nice.
|
| Is this really the best use for plastic, can't you do a lot more
| with it than that? Doesn't mixing it with sand make it much
| harder to recycle later? Isn't cement a just fine binder for sand
| (which is the actually scarce resource)?
|
| With all those concerns, though, that she's a materials engineer
| calms my inner voice eager to scream "scam".
| ahepp wrote:
| Simply based on the face that this article lists the cost of
| recycled bricks, but not the cost of traditional bricks, I feel
| quite confident saying this is an entertainment piece, and the
| bricks have no serious commercial prospects outside of being a
| conversation piece.
|
| "News" sites really love stories about inventions in Africa, but
| if you read this crap you almost certainly come away with a
| _worse_ understanding of the economy in whatever state they 're
| talking about. I stopped reading Quartz entirely, because their
| emerging markets coverage was composed entirely of this stuff.
|
| If you're really interested about innovation in the African
| economy, the investments China is making are what you should be
| reading about. That's what's actually going to change the future
| of Africa. FT has some good coverage of it all (although they're
| expensive).
| kristo wrote:
| About the microplastics and deterioration : would it be better if
| we just buried the trash in a landfill? Seems the bricks might
| offer a slight improvement or break even there
| Animats wrote:
| Nice. Using it for pavers makes sense, too. It will have some
| elasticity, which is fine for pavers but bad for structures.
|
| There are a few variants on this idea already. One is just to
| compress trash plastics into blocks, with no sand.[1] Another is
| a process more like brick making, where the material is
| melted.[2] That process is 20% recycled plastic, 80% sand etc.
|
| There are problems. UV deterioration. Cracking at low
| temperatures (probably not a problem in Kenya). Flammability.
| Poor adhesion to mortar. In the end, it's still polyethylene.
|
| [1] https://www.byfusion.com/
|
| [2] https://www.irjet.net/archives/V6/i4/IRJET-V6I4238.pdf
| terse_malvolio wrote:
| https://preciousplastic.com/
| coderintherye wrote:
| Oh wow, this is great to see! I know Nzambi from a trip to Kenya!
| She's been working on this for years and despite a great
| performing product she really struggled to find funding.
| Hopefully this coverage will help with that. If anyone is
| interested in funding her and wants to get in touch I can reach
| out on your behalf.
| sn_master wrote:
| Polyethylene is highly flammable. The article isn't talking about
| how they're solving this (are they?).
|
| This has been a problem for quite sometime now, with many high-
| profile cases (https://www.bbc.com/news/uk-41680157).
|
| This was an excellent ABC documentary I saw sometime ago on the
| same topic: https://www.youtube.com/watch?v=gnTZLzXq8fU
| josefresco wrote:
| FTA
|
| "These are high density polyethylene, used in milk and shampoo
| bottles; low density polyethylene, often used for bags for
| cerals or sandwiches; and polypropylene, used for ropes, flip-
| top lids and buckets."
|
| Are cereal bags, ropes, shampoo bottles and buckets highly
| flammable?
| sn_master wrote:
| Yes?
|
| https://www.sciencedirect.com/science/article/abs/pii/004060.
| ..
|
| If you have a counter-source, please share it.
| josefresco wrote:
| I don't, I was genuinely asking. It would seem like given
| it's popularity that would be an issue. But, crazier things
| have happened when it comes to consumer safety regulations.
|
| Anecdotally I've probably touched an open flame to
| synthetic rope, milk jugs and maybe a bucket or two in my
| life but can't say I've ever seen any of these items react
| in an uncontrolled or dangerous way.
| mediaman wrote:
| Sure, they're flammable.
|
| But the amount of BTUs in, say, packaging, is negligible,
| because it's so lightweight.
|
| When you combine lots of recycled packaging into dense
| bricks, it becomes a lot of dense BTUs, so can provide a
| lot of fuel to a fire.
| _jal wrote:
| Plastic fires are nasty. Aside from toxic fumes, plastic
| melts, So gravity will help it spread, if there's a way
| for it to do so.
|
| You're not going to cause a runaway with a lighter and a
| pop bottle without working at it. But, say, an electrical
| short in a closet with hanging synthetics can take off
| pretty quickly.
| why_Mr_Anderson wrote:
| And of top of that, burns from plastics are HORRIBLE,
| think napalm, but worse.
| kaonwarb wrote:
| In a college engineering class we produced (in teams) rockets
| emitting mach-diamond exhaust consisting of nothing more than
| HDPE rods bored in specific patterns, supplied with pure
| oxygen, and ignited.
| rootusrootus wrote:
| > supplied with pure oxygen
|
| That is key. A lot of things make a hell of a flame when
| you supply them with pure oxygen.
| darkwater wrote:
| Wood also is highly flammable and that is not stopping one of
| the most developed country in the world to keep using it to
| build houses.
| sn_master wrote:
| Wood used for construction is required by law to be fire
| treated.
|
| https://www.fp-supply.com/st-louis-fire-treated-lumber.html
| audunw wrote:
| Where? In what contexts? It's not required for houses or
| town houses where I'm from at least. From the pictures I
| guess it's mostly relevant to larger buildings?
| saltyshake wrote:
| "Over 90% of the homes that are built in the United
| States each year are constructed using wood-frame
| construction"
|
| https://awc.org/codes-standards/firesafety
| rootusrootus wrote:
| And close to 100% of those are built with garden variety
| untreated fir lumber.
| audunw wrote:
| It doesn't melt though. In fact mass timber is relatively
| resistant to fire, possibly better than steel. If I remember
| correctly, the surface chars and becomes a relatively good
| insulator of heat, so the core preserves its strength.
| syoc wrote:
| Wood really isn't that flammable either. Most thing in your
| house, furniture, paint, books, drapes etc. is on fire before
| your walls or your floor. Huge caveat on solid wood walls and
| floor.
| coderintherye wrote:
| These are mostly used for paving stones (or at least they were
| when I met Nzambi a couple years ago), so the flammability
| issue is not as much of a concern since they are not inside
| buildings but rather used for walkways usually placed in the
| dirt.
| londons_explore wrote:
| I could totally imagine a walkway made of polyethylene blocks
| could catch fire in a big way... You wouldn't want that
| walkway to be all around your house...
| liamkinne wrote:
| I would imagine the mixing in of sand would mitigate this
| mostly.
| sn_master wrote:
| I would love to see how that works. The ABC documentary is
| saying that even the big-industry produced polyethylene for
| buildings isn't properly flame-resistant, even the EU-
| approved ones.
| adrianmonk wrote:
| There was a Reddit thread where someone made a case why it
| wouldn't:
|
| https://www.reddit.com/r/worldnews/comments/ler5uc/kenyan_re.
| ..
|
| I'm certainly not an expert, and I don't know if the person
| writing in that thread is either (although their style of
| writing suggests they might be knowledgeable).
| nexthash wrote:
| A lot of people here are asking the same question and I can't
| find it addressed anywhere: how does this product not heavily
| pollute the environment? Since the bricks contain plastic they
| are prone to flaking and the formation of microplastic particles,
| which can last for thousands of years and get into the digestive
| systems of animals and humans. Also, the plastic might crack from
| constant UV radiation under the Kenyan sun. Could somebody
| explain what the rationale might be for putting 1000 plastic
| bricks/day into the environment or if there's something I'm
| missing?
| ineptech wrote:
| > how does this product not heavily pollute the environment?
|
| They do. Everything pollutes the environment, including
| breathing. Do you think solar panels don't have toxic chemicals
| in them?
|
| The sensible way to judge this relative, not absolute. The
| question you should be asking is not whether plastic bricks are
| bad, it's whether they're worse than whatever happens to the
| plastic waste in Kenya that _isn 't_ used to make bricks.
| [deleted]
| ahepp wrote:
| The entertainment industry loves stories about inventions in
| Africa. Occasionally, people make the honest mistake of
| thinking it's newsworthy. I am quite confident you will never
| hear or see of these bricks, that they are numerous different
| ways they are not commercially viable, and that they are
| probably as bad or worse for the environment than just throwing
| the garbage in a landfill.
|
| (although I'd certainly be glad to be wrong)
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