At Blackhall Engineering, we have never bought into the notion of a ‘quick turnaround’. It goes back to the old idea that you can only have two of the following three things: cheap, fast, or good. In reality, in our industry, the only two of those that combine are cheap and fast, and the problem is that ‘cheap’ rarely equates to ‘good’. And ‘fast’? All I can do here is recite the old adage, that if something’s worth doing, it is worth doing properly. What we at Blackhall can guarantee is ‘good’, although I say that at the risk of undervaluing what our Valvologists are really capable of. And whilst production of our valves does require a significant investment of time, it’s an investment that more than pays for itself.
In fact, our water valves – those that designed to be installed underwater – are made to last for 100 years or more. And they will, as long they are properly maintained and serviced. This is important, especially when you consider the scale of work necessary to replace them. An example of this would be our work at Carr Mill Reservoir near Liverpool.
A brief history of Carr Mill Reservoir
Carr Mill was first formed in the early 1700s by the damming of the Blackbrook valley. It was used to power industrial mills at the Gerard Estate. Around 1757 it was enlarged and used as a headwater for the Sankey Canal, England’s first industrial age canal. Today, Carr Mill is the largest inland body of water on Merseyside at approximately 55 acres.
Our role at Carr Mill Reservoir
We were approached in 2018 by the Canal & River Trust, who manage the site, after the need for works on the valves had become apparent. Blackhall Engineering formed part of a larger coalition. This included Framework Consultants from Arcadis, Framework Contractors from Kier Construction, and specialist divers from Edwards Diving Services. Our role was to specify replacement valves. But, as anyone who has read our previous case studies will probably have guessed, it’s almost never as simple as removing the old and installing the new.
The challenges
There are always challenges. In this case, the first thing to note is that the valves we had to replace were the originals. This made them each between 155 and 235 years old. They were fitted ‘in situ’, and chances are that they were never intended to be removed. Unfortunately, the originals had started to become tight. The spindle had failed, too, which rendered them inoperable.
In terms of the space in which we were operating, if I were to summarise the working conditions there, it would be wet, cold and thoroughly unpleasant! And whilst the importance of ensuring safe working might sound obvious, it’s not a simple box-ticking exercise that can be applied to every job. The chamber in which we were working was extremely cramped, for one. In fact there was only room for a maximum of two people. There also more than 200 years’ worth of detritus build up, equating to approximately three tonnes. Part of our solution was to install a forced air fan. And because it was so cramped, we made rigorous and regular checks for gas levels, ensuring that they didn’t become dangerous.
With a safety plan in place, we moved onto the next challenge: removing the old valves and pipework. The dam’s outlet pipe, for a start, was cast iron, five times thicker than a modern equivalent. It was harder than steel, making it too hard for conventional angle grinding. Since there was very limited access for power tools, it quickly became a real head-scratcher. In the end, we were able to cut a hatch from the outside with a diamond-bladed Stihl saw. This gave us the room to work on the cast iron pipe with a thermal lance.
Next came the job of tackling the original valve supports. This alone would take us two weeks! They were made from Ekki Wood, which is typically grown in West Africa and renowned for its hardness and abrasiveness. Typically, it also infamous for dulling tools! You can’t nail into it, and you certainly cannot split it. It’s solid. In fact, when you compare its weight-to-volume ratio to that of oak (it’s heavier by 18lbs per cubic foot!), you get an idea of just how robust the material is. Interestingly, its bark is traditionally ‘sniffed’ as a remedy for headaches, which is ironic given the trouble that it caused us. Fortunately, we were able to find a solution. By drilling multiple cores, we were able to remove the stubborn material from the chamber.
Installing our 100 Year Life valves
From here it must have been plain sailing, right? Well, in a word, no. Or to use two, not quite. On hauling the main original valve from the chamber, we discovered that it contained asbestos. This, of course, was a bit of a scare. We halted proceedings and had the fragments independently lab tested. and luckily. they were asbestos free so work resumed.
Eventually we were able to dispose of the asbestos safely, and having established that there was no more present, work was able to resume. With the old valves removed and the chamber cleared, we set to work installing four of our PN16 Blackhall Series 3400 100 Year Life® Metal Faced Gate Valves. We also installed new guard valve inlets, discharge valves, plus new extension rods and pedestals at the top of the valve tower. This new equipment is state-of-the-art. Not so much as a single bolt was ‘skimped’ on. At Blackhall we know that quality is everything, and such is the case with the new valves at Carr Mill.
Our learnings from Carr Mill Reservoir
As a case study, what this project shows is the importance of great people. With a positive attitude, you can overcome even the greatest of challenges. When you combine that with the advantages of our 100 Year Life assets, you have a genuine, long-term solution. More than that, you have one that’s reached both safely, and with minimal inconvenience to the public.
Looking to the future and our work at Carr Mill is far from done. But that’s a good thing. The replacement of the valves is just one aspect of a key service level that we really pride ourselves on. Going back to what I mentioned earlier, about the importance of proper maintenance and servicing, and we will continue to work with the Canal & River Trust at Carr Mill to ensure everything is kept in full working order. The very point of commissioning us to deliver the valve
