A world class industrial heritage site

Gasworks Histories

Demolition of the Garston Gasholders

An interesting Article related to the demolistion of the Garston Gasholders outside Liverpool (UK).

Look at what they did with the Dublin Gasholders.


(Thanks to Dr Russell Thomas and his LinkedIn post)

Week one 2014

While the last Sunday in 2013 “went with a bang” the first in 2014 was “more of a pop” – seven visitors were recorded.

Tuesday’s work day was spent with Operations volunteers catching up after the holiday break and generally “chewing the fat”, therefore little “work” was accomplished. We did however, commit Tom to support the FOH folk on the first and third Sundays, while John would “do” the second and forth Sundays. Mack, Keith, and the others will assist as and when available. We are guessing at this time, but we may have the boiler back in action late March or April. We are pleased to report Tuesday’s (today)visitor numbers were 6/7th of the previous Sunday.

Bill C. has generously shared his information on the gasworks railway siding, and this has been posted for general and public view on our alternate website. ( The IhdunedinNZ web site layout has been modified to accommodate the increasing Gasworks info – and hopefully becoming a useful resource for our volunteers – please check it out.)  http://ihdunedinnz.weebly.com/

Is half the story —

Motivated by a positive reception to my last Water Gas infoblog, and while personally expanding the detail today, it became clear I should have included this additional information, now provided here.


 On the Braemar street wall, the water gas main exited the building at the high level and connected to the pipe up-stand visible directly below the window. This in turn connected to the water gas holder. The pipe section partially visible front-right of picture is a section of the underground connection to the holder recovered during site work at the current gas holder legs.

This site, on the Western wall of the Engine house extension, once sported a venturi type flow meter, measuring the Water gas flow into the foul main.


This pipe (circled)  on the northern wall of the Anderson room, is all that is left of the steam connection to the water gas plant.



Dunedin’s Water Gas.

Technical descriptions of water gas plant can be found in the GWM library, and on the internet. A couple of information panels are also provided in the Donkin annex of the museum. Therefore, detailed technical description is not reproduced here. Never-the-less a brief summary of the technology is necessary, and included, to enhance understanding of this blog. Water gas production required the interaction between water (steam) and carbon (coke) to reduce water into Hydrogen and (flammable) Carbon Monoxide. If conditions were not correct, (inflammable) Carbon Dioxide could be produced and this was not good! A secondary hydrocarbon enhancement stage was generally provided to produce an acceptable Calorific Value (CV). Production was by a batch system, with gas produced during  a “run” cycle, followed by a recharging cycle. As such, water gas systems required some sort of buffer or storage facility, in Dunedin’s case, this was the water gas holder situated near the current gas holder legs.

Known under various names, water gas was produced at the Dunedin Gasworks site, in two different eras. The first plant was dismantled and shipped north to Napier to assist the town recover from the disastrous 1931 earthquake. It was never returned. A second production plant was installed in 1952, and continued until the cessation of coal gas production. Early plant was manually controlled with coloured time-controlled indicators advising the operator which appropriately coloured valve or handle to adjust. Later models were automatic.

The Water gas plant was situated approximately where the traction engine shed sits today. As previously noted, the water gas holder was sited close to, (but smaller than) today’s museum gas holder legs. Parts remaining at the museum today are the water gas main, from the production plant to (almost) the water gas holder, a small portion of the underground connection to the gas holder, and the connection to the foul main where the water gas was mixed with coal gas for filtering, storage and distribution.

The yellow pipe is the water-gas main from the production plant (previously in the distance) to the water-gas holder (previously behind the camera)


 The water-gas connection to the foul main (circled). Long gone pipework connected this valve to the water-gas holder. 

We need a bloodhound!

Observant volunteers and visitors may have noticed the unusual markings on the floor just inside the internal door to the main Engine House. These represent the position of a long gone steam-engine driven electrical machine. The original purpose of the machine is not known by the writer, or even whether it was an alternator or a generator. Some local legend indicates the machine, at times, exported electricity to the DCC tram network, suggesting it was a DC machine. However this has not been confirmed.

More certain is that the machine was sold to Downers Ltd for use on construction of the Lyttleton tunnel.

Does it still exist, and if so where is it now?

Wouldn’t it be nice (song title pun not intended) to locate this machine and return it to its rightful position, perhaps as a swap for the Sp8s boiler or a steam winch!

Anyone interested in taking up this cause? Could we make it a project?

Being of the electrical persuasion and declaring a total bias in favour of progressing, but with research not my “thing”, I would happily assist any researchers to advance this matter – John

The outline on the floor indicates the position of the engine and the electrical machine.

 Behind the left hand exhauster – now the Reader – can be seen a very interesting steam engine and its associated electrical machine.


There’s an old piano, and its playing hot –

– Behind the green door. (muso’s and rock-n-rollers will recall the original 1956 song by Jim Lowe, or perhaps the 1981 version by Shakin Stevens!)

“John! See those (green) doors over there”, pointing to the DE boiler solid fuel area external doors, “ they came from ’round the front, where the main entry glass doors are now.”
“That’s interesting Bob, I didn’t know that, what was there before?”
“A big sliding door with a smaller “trap door” attached”
“Obviously the larger hole has been framed up to accommodate the new doors”
“Yeh. Back when smoking was banned on site, Joe (not real name) would sneak out for a smoke and when a boss came by he would jump back in through the trap. One day it happened just like that, except the main door was already open, and Joe jumped through the trap straight into the brick wall, doing more damage to himself than the wall. The boss just turned and walked away. ”

“See those pipes”, Bob pointed to the gas main exiting the engine house toward the detarrer and the ammonia washer, “they used to be above the ground, we filled this area in so to allow vehicle access to the rear of the Anderson room.”

Having previously partially excavated the said pipes to exhibit, only to have them filled in again, John kept silent.

“The (probably coke -Ed) trucks used to back in, in front of the condenser towers to get to the boiler house. They didn’t always get it right! See this damage” Bob continued, pointing to the Engine house extension NW corner.

“Now that’s really interesting,’ John replied.

“Yeh, after several hits, they finally gave up returning the wall to “square” and just patched it up on the (45*) angle.”

The boiler house doors today – relocated from the “front” of the Engine House


The boiler house extension, after a few bumps they just left it! 



What lies Beneath ?

This week contractors replaced the temporary sump pump, the subject of a recent blog. Recording the event lead the blog editor to consider this addition to the “ volunteer resource series” of blogs.

Legend has it that the gas works site is located on and around the bed of a stream, sourced near the old St Kilda Quarry, now Francis Hodgkin’s, and flowing into the harbour. Over the years the stream bed was filled and piped, and subsequently hidden from view.

Certainly, South Dunedin folk are well aware of the high (shallow) water table that rises and falls with the tide. The museum is not exempt, and with a labyrinth of now often open underground pipes (the subject of a future blog) without intervention, the museum would be regularly flooded. Four sump pumps are installed on the museum site, all now serviced and maintained by DCC city properties. Two pumps are associated with the Fitting shop, under the library floor and outside at the library Eastern wall. Two pumps are associated with the Engine House, one draining an external sump near the condenser towers, and the other draining an internal sump at the eastern end of the Electric Donkin exhauster. The latter pump is the one replaced this week. Operations volunteers routinely monitor these pumps, and note while running times increase during rainfall periods, even in dry times the sump pumps regularly cycle with incoming flows. In other words, these pumps are essential to preventing ground water flow into the museum buildings.

Today’s pictures record the two Engine House pumps, now both new this year, and the last remaining section of old, and then unused, drainage pipe recovered from the now Gas holder legs site during early days at the museum. Also included is a pix of the painting indicating the first retort house, clearly showing a stream in the foreground.

This section of drainage pipe recovered from early site works.


 This pump drains the external sump.


 This pump drains the internal sump, under the chequer plates


This pix, reproduced in our museum book, is mounted on the wall near the beam engine.


Today 01/10/13, Lawrie Forbes from Zealsteel Ltd, delivered to us a donation box, intended to encourage donations toward our boiler replacement. To our total and collective delight, the finished article was not just a box, but a sculpture in metal, made from totally relevant raw material, and entirely appropriate for location in the boiler house. Pictures tell the story, we are told. In this case the pix associated with this blog record the genuine skill and forethought gone into the creation of the money box. That is only half the story!

Lawrie advises:

*The background plate is fashioned from steel recovered from the Kensington Gas holder.

*The door is a stoke hole door from the scotch boiler on the TeWhaka (steam ship). The boiler, and therefore the door, were originally installed in the Greymouth tug, Kawatiri, and later transferred to the TeWhaka.

*The name plate “TeWhaka”  is a genuine artefact from the steamer, having been installed in recent years due to legislative requirements, after the original plate had been removed. Originally “straight” the plate has been curved to fit the sculpture.

*While Lawrie retains ownership of the sculpture, he advises we have long term loan as long as we wish _ Thank you Lawrie


Lawrie Forbes priceless “money box”. 


LFG – Land Fill Gas – a volunteer resource doc.

For many, the model in the Fitting shop of the Green Island LFG project, is just that – a model. This blog provides a link to some of the background and technical aspects of that ill-fated project.
Follow the link – and click on the Green Is LFG page tab. (Another interesting gas memory is on the Energy tab – item 4.)




The LFG model.  The link above takes you to the IHdunedinNZ website.




What’s Gas?

As with all artefacts, – some things wont last forever. Useful as an on-going back-up, and also as a volunteer education resource, the writer has made a commitment to record various hard copy information on the blog, and therefore, saved, backed up, and accessible to all. In today’s record the works’ chemist’s analysis record of the day’s gas sample.