Pipe selection for cold water
The rotten section of the pipe in the apartment I bought prompted me to take up the issue of choosing pipes for cold water.
In the photo in the place where the repair clutch was installed there was through corrosion and near it a 15 cm section with external corrosion of the pipe. In this case, the rest of the pipe in the apartment and part of the pipe to the decayed area in normal condition.
I decided to replace the pipe, and since I change it, so the entire branch of the HVS, especially since it is not large: the bathroom and kitchen are nearby and are powered by one riser.
So, let’s start with the requirements that I make to the pipeline:
- Chemical inertness;
- Bacteriological inertness;
- Long service life (corrosion resistance, etc.);
- Pipe performance (allowable pressure, etc.);
- The convenience of installation;
- Maintenance service.
- The cost of the pipe and installation.
I had to study a huge amount of material on various pipes. In some cases, decisions on the applicability of pipes are unambiguous, in some they are not.
So, we will begin with the main division of pipes: pipes polymer and metal.
Polymer pipes that I examined:
- PABX-Al-Pex metal-plastic
- Pexa cross-linked polyethylene
- Galvanized steel
- Corrugated stainless steel pipe
- Exotic 🙂 thick-walled stainless steel and nickel-plated long pipe chutes.
I will consider the pipes in the order of requirements indicated above, giving an assessment according to a three-point system (1 – bad, 3 – good)
1. Chemical inertness
Polymer pipes are relatively chemically inert. However, polypropylene is worthy of a rating of 2+. This is caused by information about the lack of “protection” of polypropylene produced in the Russian Federation, Turkey and neighboring European countries from the effects of chlorine. Although there is no disaster in this. I did not find such information about other polymer pipes. Evaluation of the remaining pipes -3 Galvanized pipes in terms of chemical inertness are not the best choice. “Wash” of zinc is the place to be. If the pipe has a real hygienic certificate, then this may not be dangerous, however, there is a firm belief that the zinc pipe should not be used in the food water supply. At least, sometimes they write on galvanized dishes, buckets, not for writing products.
Grade – 1
Stainless Corrugated Pipe – Grade 3.Cofulso pipe is made of stainless steel SUS 304, has the necessary certificates.
Copper is less prone than galvanizing to wash out oxidation products, nevertheless, this material is popular in Europe and is gaining popularity in Russia. There is one BUT – I read an article with studies on the effect of copper compounds that enter the human body. In short: in their youth, copper compounds are beneficial, and after about 50 years, when the metabolism in the body changes, copper already does more harm. Since I’m less than 2 decades old, and I hope the water supply system will stay longer, I estimate copper at 2 points.
3 points – Metalloplast, cross-linked polyethylene, HDPE, stainless corrugation.
2 points – polypropylene, copper.
1 point – galvanized.
2. Bacteriological inertness.
Polypropylene – solid 1 is even more than cross-linked polyethylene is prone to the formation of films on the inner surface of the pipe. Some bacteria, such as legionella, reproduce remarkably in these films.
In addition, while attending courses at the St. Petersburg Institute of Cryogenic Engineering, I also heard this information from teachers. A similar assessment for metal and cross-linked polyethylene. However, I didn’t find such information on PND, let it be rated 2
Galvanization is inert, however, after the destruction of the zinc layer, as well as due to the overgrowth of the pipe passage by various deposits in them, an environment for bacteria to live in the deposits and rust. Therefore, rating 2.
Corrosion-proof corrugation, as I think, due to the presence of those same corrugations, in which dirt and other deposits can linger and so on. Deposits, like galvanizing, are prone to form an environment for bacteria rating 2.
Copper – rating 3. Various studies confirm the antibacterial properties of copper pipelines. In the same ABOK article, the link to which is above, in the comparison of polymer pipes and copper, there are even figures for the bacterial resistance of the copper pipe.
3 points – copper
2 points – PND, galvanizing, corrugated corrugation
1 point – polypropylene