Biomythology: Eastgate-gate 2 (or How the Eastgate Centre, Harare, is not like a termite mound)

December 13, 2012 by DaveParr 17 Comments

As I began on Tuesday, the Eastgate Centre is good design. It is NOT good biomimicry.

To be fair, the project was partially designed on the science as it was understood at the time. But, as far as I can see only partially. The design falls down in terms of biomimicry on two points

1)    Termite nests (probably) do not ventilate the way that Mick Pearce thinks

2)    Termite nests do not stay within “1 ^oC all year around”

The first of these is an understandable mistake considering the published literature of the time. Recent research (last 5 years) has been, as far as I’ve been able to find, the first to start poking holes in long established termite mound ventilation models. Let me explain…

What follows is a reworking of part my dissertation. Plagiarism is not encouraged. This work is protected through creative commons licences. The suggested academic reference is:

Parr,D., 2012, Biomimicry Lessons for Building Ventilation, Submitted for qualification of Environmental Design of Buildings MSc, at Cardiff University – Welsh School of Architecture. Treatment available at biomimicron.wordpress.com

UPDATE 23/04/2013: Since this set of articles was published, I have had the good fortune to get to talk to both Rupert Soar and Mick Pearce extensively about their work, and recieved information from Dan Phillips. In being able to get EVEN MORE information from all these people, I now feel that this series of articles is still only part of the discussion. There is nothing in these articles which is outright untrue, however they miss a significant proportion of Mick, Dan and Arups good work. Look out for Eastgate Now: Redux coming soon…

Induced ventilation

Various researchers proposed an induced or stack effect ventilation process in the famous ‘open chimney’ termite mound design. A system where faster wind speeds elevated from the ground at the top of the stack (≈2m), compared to the slower wind speeds at ground level, leads to a pressure difference vertically through the central chimney. The resultant air flow constitutes the ventilation.

Metabolism driven thermosiphon ventilation

What about those mounds without a large opening at the top? Well, the idea proposed (and current during Mick Pearce’s time I expect) was effectively based on ‘occupant heat gains’. All those busy little insects, bustling around growing fungus (I wasn’t kidding about that, they actually do have subterranean ‘gardens’) means they are respiring, burning sugars to move around and function, i.e. metabolising. Imagine yourself getting hot when exercising, that’s all it is. 1 termite isn’t going to generate much heat, but with millions of the suckers in each nest, the heat gain is cumulative.

Hot air rises due to buoyancy, I learnt that in primary school (we had a plumber come in to teach us one afternoon, still unsure as to why…), and as a result it can rise through the main chimney structure (which is partially present even in ‘capped’ mounds) and then out through the cap, which has numerous branching tunnels between the chimney and the surface. As the air rises, it creates a negative pressure at the base of the nest, which is filled by air entering the nest from the exterior.

From Turner and Soar, 2008

So?

This is evidentially what inspired the Eastgate Centre, and is in itself not Bad Science (yes, that phrase is getting capitals. It’s a ‘thing’ now). In fact it’s quite good science. It was thought to be correct at the time, and it was based on observation and data collection.

It’s easy to be intelligent with the benefit of hindsight, but what annoys me about this particular case is the amount of people who aren’t. This was current science in the 90’s. That is almost a quarter of a century ago. However, it’s not even ‘the whole story’.

The Bad Science

There are two massive issues with the way reporters praise the science here. One I drew attention to on Tuesday was the inclusion of fans which draw power externally. Termites don’t have fans. D’uh.

One I DIDN’T point out was the totally ridiculous claim that is more common on the internet than arrogant know-it-all’s with nothing better to do than correct everyone else on their tiny slip ups (Yes, I’m being meta, which utterly legitimizes me picking up on others peccadillo’s).

The statement: “Termite mounds never deviate more than 1 ^oC throughout the year to grow their fungus gardens”

The stats:

Graph of temperature 1m underground, and in termite nest, 1m underground. Also Turner and Soar, 2008.

………..

……….

15 ^oC

Seriously? This is like Ol’ Al’s infamous ‘climate change hockey stick’. Look at the data, then look at the claim. Then look back at the data. Here is the Eastgates ‘Inconvenient Truth’. Here is the secret that Big Green Construction and The Biomimicrists Templar DON’T WANT YOU TO KNOW! WAKE UP SHEEPLE! 1 DEGREE CENTIGRADE IS AN INSIDE JOB! If I could find home addresses for every person I’ve heard report the ‘±1 ^oC’ line, I would paint this graph across their bed sheets for them to find in the morning, and weep contrite tears into.

Meanwhile I perch on a roof as the accumulated filth of all their Bad Science and Poor Research will foam up about their waists and all the ‘reporters’ and ‘designers’ will look up and shout “Save us!”…

And I’ll look down at the word count and cut this segment down to size. Next up: What might actually be going on. Stay hopeful for Part 3!

References: Turner, J. & Soar, R., 2008. Beyond biomimicry: What termites can tell us about realising the living building. Loughborough, Loughborough University, pp. 1-8.

Biomythology: Eastgate-gate (or How the Eastgate Centre, Harare, is not like a termite mound) by Biomimicron: D. Parr is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

P.S. Termite’s have SO FEW fans, that a google image search for “termite fan”, turned out this:

Who IS Danilo Termite?

He seems to be an Italian actor who’s work to date consists of an action/thriller called ‘Under Reflex’, and a promo for an Italian ska/hiphop/rap group called ‘Sud Foundation Krù‘. Work that has entirely passed me by, but seems to be enough to elicit montages of your face on the internet.

Wierdly Sud Foundation Kru have a song titled ‘Illumanti‘ with a banging sample from power metal mainstay Gamma Ray.

After that though the trail ran cold, but I think I’m onto something… If I should die under mysterious circumstances, and it wasn’t my Uni house mate, then you know where to look next…