MLCP – Coils Vs. Straight Lengths

Flexible MLCP  

Piping made from multilayer composite pipe is a viable alternative to copper because it offers flexibility, speed of installation and the elimination of hot works on site.   
First introduced in the UK in the 1970s, MLCP has seen growth in popularity alongside the increased use of renewable energy technology – such as underfloor heating. MLCP has also seen less dramatic price fluctuations in recent years compared with copper and steel.  
The flexibility of the pipe, together with the use of press fittings, is where MLCP can offer significant savings to plumbers on installation time. The pipe can be bent readily, allowing efficient routing around the building. Once bent, it retains its form and stays in position. As Multipipe MLCP has an aluminium mid-layer, it meets the NHBC requirements in detecting buried services, so there is no need to worry about finding it in walls.  
In this Tech Tuesday post, we look at where coils and straight length should be used and the benefits of each, so you know what is best for your project.   

Straight Length MLCP  

Straight sticks for pipes have been around the longest, and having talked to our customers; it seems that it is the preferred choice. Why? Well, copper and steel tube is only available in straight lengths. As the only installation method for years, it’s like a comfort blanket, and often installers tend to stick with what they know.   
There is also the other point, neatness. When you look at a spaghetti of coiled pipe, it is enough to put you off. A nicely clipped pipe with its ruler-straight lines is enough to keep even the most critical OCD plumber happy. Therefore, straight length is great for when pipes are on show. Rest assured, Multipipe MLCP comes in straight lengths for those projects that demand it.  

Coiled MLCP  

A coiled pipe is usually reserved for underfloor heating systems. However, when running circuits for radiators or hot and cold pipes under a floor, a coiled pipe is a great option. You can thread Multipipe MLCP through joists and limit the number of joints under the floor! Our previous article demonstrated how this is a requirement of hot and cold services.   

Benefits of Coiled MLCP  

The coiled pipe has less aluminium than its straight counterpart, which means it is more flexible than straight sticks. As there is less aluminium in coils, the cost per meter is less, making financial sense to use coiled MLCP where possible.   
Another market sector where MLCP is particularly suited is high-rise residential projects, where it is being used in risers and downstream in corridors and apartments. The flexibility of coils over straight bars means installation times are generally 30-40% quicker than when using traditional copper or steel.   
For projects where you want to reduce the number of fittings, coiled MLCP is an ideal choice.  
Also, the risk of theft is minimal because MLCP has no scrap value. So next time you are using pipes for fit-out, consider if coils are a better option.   

What are the limits of Coiled MLCP?  

Coils are only produced up to 32mm, and beyond that, the product would not coil well. MLCP has a metal base meaning that it is stiffer than a standard plastic pipe; therefore cabling 32mm pipework might be quite difficult. However, it is far less prone to expansion noises than standard plastic, thanks to the lower expansion rates.  

Did you know?  

Not all Multilayer pipe systems are WRAS Approved – Please check before purchase or buy Multipipe with confidence knowing that our product is WRAS approved. This brings the added benefit of being able to use your UFH project offcuts for all your water plumbing needs – good for your wallet and the environment! 

What kind of customer service do you want?

It’s been said that customer service can be any two out of good, cheap, and quick, but seldom all three.
– If it’s high quality and inexpensive, you may have to wait
– If it’s delivered fast and is inexpensive, you may have to accept lower quality
– If it’s delivered fast and is high quality, there’ll be a premium price
OK, that’s a little tongue in cheek but let’s see how it applies to the construction industry, and especially to plumbing and heating installers.
When you need to source products from a manufacturer or merchant with the right level of technical support and backup service, it could go like this:
Merchant – We can certainly supply those products within your budget. However, that budget doesn’t allow us to provide you with the very best on the market. What level of quality is important to you?
Merchant – We can get most of those products to you on that date. However, on such a tight timeline, we can only deliver part of your order as we have to order in the rest.
Multipipe – We hold plenty of stock, and we can get your order to you on time. As we only stock the highest quality, you’ll need to budget £xxxxx. Can your budget cover that?
What level of service works for you?

Secondary Recirculation Systems

Why Use Secondary Recirculation Systems

As houses get bigger and clients demand even more from their installer, one of the biggest issues is delivering hot water quickly and efficiently to the hot water taps. The only way to efficiently do this is by setting up a circulation loop from the cylinder to the tap emanating the dead leg between the two. Although there are no legal requirements to fit one, HSE best practice is to deliver 50°C water within 1 minute to a tap; this is for legionnaire control.  

How Does a Recirculation System Work?

The idea is you have your primary hot water pipe flowing through your house. Besides this, you have a “secondary recirculation pipe”, which travels beside the hot water primary pipe all the way to the extremities of the system. The secondary pipe taps into the primary to join the two pipes. The cylinder then has a hot water circulation pump (normal heating system pumps will not work). The pump is set to push the water through the primary pipe to the tap, and it then returns on the secondary pipe, thereby keeping your hot water hot all the way to the tap.  

Limits of a Secondary System 

With 60-70°c water flowing through it for most of the day, the secondary pipe has a hard life. With a heating system, you can flush through the water’s pH and impurities. However, you cannot do this with a recirculation water system. Also, you are transporting oxygenated water, which can have detrimental effects on parts of a system. This is why all plastic pipes made under BS 7291 cannot be used on these systems. However, because of how our pipework is made, MLCP can be used with recirculation systems as Multipipe MLCP is made to a different standard than plastic pipe.   

Our Top Recommendations for Recirculation Systems 

  1. Where possible, insulate as much of the pipe with good quality, thick insulation. This will limit the heat loss going back to the cylinder.   
  2. Only use a WRAS approved pump specifically designed for hot water circulation.  
  3. Fitting a timer to the pump is a great idea for energy efficiency to stop the circulation when not needed.  
  4. You can use a rule of thumb of 2 sizes smaller than the flow pipe for sizing the right pipe.  
  5. If you have reduced flow rates at your tap, you might need to fit a flow restrictor on the secondary pipe to push water to the tap.  

Towel Rails

Did you know fitting a towel rail on the secondary circuit can be done? This is great because they keep constantly hot! (as long as the timer runs). Ensure you consider the heat loss to your cylinder, but also, they *MUST* be WRAS approved and made of stainless steel or copper. Lastly, the towel rail should only be fitted to the return circuit of the hot water system.