Polyethylene (PE) pipes are commonly used for plumbing systems due to their versatility, low cost, and ease of installation. However, there are two main types of polyethylene pipes: cross linked polyethylene (PEX) and non cross linked polyethylene.
The primary difference between the two is the level of cross linking between the polymer chains. Cross linking refers to the process of chemically bonding polymer chains together to create a stronger, more durable material. Cross linked polyethylene (PEX) is created by adding a chemical agent to the polymer, which initiates a chemical reaction that links the chains together. This process creates a more durable and heat resistant material that is ideal for use in high temperature applications such as hot water systems.
On the other hand, non cross linked polyethylene is created without the addition of a cross linking agent. This material is less durable and has a lower maximum operating temperature than PEX. It is typically used in lower temperature applications such as cold water systems.
In terms of plumbing fittings, PEX fittings are designed to work specifically with cross linked polyethylene pipes, while non cross linked polyethylene fittings are designed to work with non cross linked polyethylene pipes.
The main differences between cross linked polyethylene (PEX) and non cross linked polyethylene pipes and fittings are the level of durability and heat resistance, as well as their suitability for different temperature applications.
Here are some additional differences between PEX and non cross linked polyethylene pipes and fittings:
Flexibility: PEX pipes are more flexible than non cross linked polyethylene pipes, which makes them easier to install around corners and obstacles. This flexibility also allows for expansion and contraction in response to changes in temperature, which reduces the likelihood of the pipes bursting or cracking.
Chemical resistance: PEX pipes are more resistant to chemicals than non cross linked polyethylene pipes. They can withstand exposure to common household chemicals such as bleach and drain cleaners, which can damage non cross linked polyethylene pipes over time.
Cost: PEX pipes are generally more expensive than non cross linked polyethylene pipes, but they offer superior durability and longer lifespan, which can make them a more cost effective option in the long run.
Installation: PEX pipes are typically installed using a crimping tool or a compression fitting, while non cross linked polyethylene pipes are often joined using heat fusion or mechanical fittings. The installation process for PEX is generally faster and easier than for non cross linked polyethylene pipes.
Compatibility: PEX pipes and fittings are not compatible with certain chemicals, including some types of chlorine based disinfectants. It is important to check the compatibility of the pipe and fittings with the chemicals that will be used in the plumbing system before installation.
PEX pipes and fittings offer several advantages over non cross linked polyethylene pipes and fittings, including greater durability, flexibility, and chemical resistance. However, the choice between the two will depend on the specific requirements of the plumbing system, such as the maximum operating temperature and the types of chemicals that will be used.
Maximum Operating Temperature: PEX pipes are able to withstand higher temperatures than non cross linked polyethylene pipes. The maximum operating temperature for PEX pipes is typically around 200°F, while non cross linked polyethylene pipes have a maximum operating temperature of around 140°F.
Longevity: PEX pipes have a longer lifespan than non cross linked polyethylene pipes. PEX pipes can last up to 50 years, while non cross linked polyethylene pipes typically last around 25 years.
Resistance to stress cracking: PEX pipes have a higher resistance to stress cracking than non cross linked polyethylene pipes. Stress cracking can occur when pipes are exposed to certain chemicals or when they are under stress due to changes in temperature or pressure.
UV resistance: PEX pipes are resistant to UV radiation, while non cross linked polyethylene pipes are not. This makes PEX pipes a better option for outdoor applications where the pipes will be exposed to sunlight.
Daloy ng daloy: Ang mga PEX pipe ay may mas makinis na panloob na ibabaw kaysa sa mga hindi cross linked na polyethylene pipe, na maaaring mapabuti ang daloy ng daloy at mabawasan ang pagkawala ng presyon. Maaari itong maging kapaki-pakinabang sa mga aplikasyon kung saan kinakailangan ang mataas na daloy ng tubig.
Ang mga pipe at fitting ng PEX ay nag-aalok ng ilang mga pakinabang kumpara sa mga non-cross linked polyethylene pipe at fitting, kabilang ang higit na tibay, flexibility, chemical resistance, mas mataas na maximum operating temperature, mas mahabang buhay, paglaban sa stress crack, UV resistance, at pinahusay na daloy ng rate. Gayunpaman, ang pagpili sa pagitan ng dalawa ay depende sa mga partikular na kinakailangan ng sistema ng pagtutubero, tulad ng pinakamataas na temperatura ng pagpapatakbo, mga kemikal na ginamit, at rate ng daloy.
Narito ang ilang karagdagang pagkakaiba sa pagitan ng PEX at non cross linked polyethylene pipe at fitting:
Oxygen permeability: Ang mga PEX pipe ay hindi gaanong permeable sa oxygen kaysa sa mga non cross linked polyethylene pipe. Ito ay maaaring maging mahalaga sa ilang partikular na aplikasyon, tulad ng sa mga radiant heating system, kung saan ang oxygen ay maaaring magdulot ng kaagnasan at pinsala sa system.
Pagpapadala ng ingay: Ang mga PEX pipe ay mas tahimik kaysa sa mga non cross linked polyethylene pipe, dahil mas kaunting ingay ang ipinapadala ng mga ito sa mga pipe. Ito ay maaaring maging isang mahalagang pagsasaalang-alang sa mga aplikasyon sa tirahan, kung saan ang ingay ay maaaring maging isang istorbo.
Mga pag-apruba ng code: Ang mga pipe at fitting ng PEX ay inaprubahan para sa paggamit ng karamihan sa mga plumbing code sa North America, habang ang mga non-cross linked polyethylene pipe at fitting ay maaaring hindi maaprubahan sa lahat ng hurisdiksyon. Mahalagang suriin ang mga lokal na code ng pagtutubero bago pumili ng pipe at fitting system.
Lakas ng pagsabog: Ang mga PEX pipe ay may mas mataas na lakas ng pagsabog kaysa sa mga non cross linked polyethylene pipe. Nangangahulugan ito na mas malamang na sila ay sumabog o mabigo sa ilalim ng presyon.
Availability: Ang mga pipe at fitting ng PEX ay mas malawak na magagamit kaysa sa mga non cross linked polyethylene pipe at fitting. Maaari nitong gawing mas madali ang paghahanap ng mga materyales na kailangan para sa isang proyekto sa pagtutubero.
Sa konklusyon, ang mga pipe at fitting ng PEX ay nag-aalok ng ilang mga pakinabang kumpara sa mga non-cross linked polyethylene pipe at fitting, kabilang ang mas kaunting oxygen permeability, mas tahimik na operasyon, mas malawak na pag-apruba ng code, mas mataas na lakas ng pagsabog, mas malawak na availability, bukod sa iba pa. Ang pagpili sa pagitan ng dalawa ay nakasalalay sa mga partikular na pangangailangan at pangangailangan ng sistema ng pagtutubero, pati na rin ang mga lokal na code at regulasyon sa pagtutubero.
