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 Pex Tubing Store

Pex Tubing Store

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 [Pex Tubing Store]- Guaranteed Lowest Prices for all your PEX Plumbing, Hydronic and Radiant Heating supplies. We sell PEX Tubing, PEX Fittings & Valves, Plumbing and Radiant Heat Manifolds, Tools. We also carry Copper Fittings, Brass Ball Valves, Pumps, Mixing Valves, Air Eliminators & much more.
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What is PEX Tubing?

PEX tubing (Crosslinked polyethylene) is flexible plastic tubing, extruded from HDPE (High Density PolyEthylene). HDPE is a common type of polymer that is used in production of plastic beverage bottles, food containers, shopping bags, etc.
Crosslinking process creates bonds between molecules of HDPE, making it stronger and better. Crosslinking also improves the resistance of PEX tubing to chemicals, extreme temperatures and allows for greater flexibility.
PEX tubing is also known as "PEX pipe", "PEX piping" and "PEX tube". All of these names refer to the same product.
PEX is available mostly in continious run coils or spools to simplify the storage and handling process.
PEX tubing is measured by a nominal size (commonly mistaken with OD or ID) and has an outside diameter (OD) which is greater than nominal by 1/8 of an inch. For example, 1/2" PEX tubing has an OD of 5/8", 3/4" PEX tubing has an od of 7/8", etc.

PEX Tubing with Oxygen Barrier

Oxygen Barrier PEX tubing (also known as "Radiant PEX" and "Barrier PEX") is PEX tubing that has a special polymer (EVOH, or ethyl vinyl alcohol copolymer) coating applied to its external surface. Purpose of the EVOH polymer is to increase pipe's resistance to oxygen diffusion.
With regular PEX pipe (non-barrier, or, simply plumbing PEX), oxygen molecules (O2) can diffuse through the walls of the pipe into the water, and corrode ferrous parts inside the system. Since plumbing systems contain no ferrous parts, there's no need for the Oxygen Diffusion Barrier. However, heating systems often contain cast iron circulator pumps, radiators, boiler heating elements, and other parts which are subject to corrosion if exposed to oxygen molecules. Oxygen Barrier significantly reduces the amount of diffused oxygen, eliminates frequent system maintenance and extends the life of a radiant heating system and it's components.
The most common sizes for this type is 1/2", 3/4" and 1".
1/2" PEX Tubing w/ O2 barrier is the size used for nearly all radiant floor heating projects (below subfloor, in-floor, in concrete slabs, etc.).
3/4" PEX Tubing w/ O2 barrier is used for snow melt applications, baseboard radiators, cast iron radiators and HVAC applications.
1" PEX Tubing w/ O2 barrier is the size used for outdoor wood furnace installations. Tubing is usually insulated and buried underground below the ground freezing level. Also used for main supply and return lines.

Non-Barrier PEX tubing (PEX plumbing tubing)

Non-barrier PEX tubing is used for PEX plumbing applications. It is available in a large variety of sizes - from 1/4" to 2" in diameter.
Plumbing with PEX is popular for many reasons, such as:
  • PEX tubing is more flexible than rigid pipes (such as copper and CPVC), requires a lot less fittings and weighs less.
  • It is cost-effective and widely accepted. On the average, price of PEX tubing is 6-8 times less the price of copper pipes.
  • It will not burst like copper pipes when water inside the tubing freezes.
  • PEX tubing doesn't condensate like copper and will not leave stains on drywall.
  • There's no need to install water hammer arrestors.
  • It is much healthier that copper pipe installation, since it does not invoice the use of acid-based fluxes.
Non-barrier PEX is not intented for use in closed loop radiant heating systems, since it does not have an oxygen diffusion barrier.
Moreover, Barrier and Non-barrier PEX are often manufactured from different raw materials (compounds), so that each type has the properties needed for installation in particular system - plumbing or radiant heating. For example, Oxygen Barrier PEX tubing has to be more flexible and have better thermal features (to respond well to temperature fluctuations). Non-Barrier PEX, on the other hand, has to be more stiff (to withold more pressure) and have better chemical resistance properties (such as resistance to chlorine).

PEX Tools, PEX Fittings, Crimp and Cinch connection methods

A standard Crimp connection method requires a proper size
PEX Crimp Tool (also called "PEX crimping tool", or "PEX crimper"), a Go-No-Go gauge, Copper Crimp Rings and Crimp-style PEX fittings.

Pictures are crimping tool, decrimping tool and crimp ring, respectively:
PEX Crimping Tool Decrimper - Crimp Ring Removal Tool Full circle Copper Crimp Ring. ASTM F1807.

This is how a normal installation is done:
How to install PEX: Making a crimp connection.
Tubing is cut to a required length, PEX fitting is fully inserted into the pipe, crimp ring is positioned 1/8"-1/4" from the end of pipe. PEX crimp tool jaws are fully opened and positioned over the crimp ring. The jaws are fully closed. The connection is checked for acuracy with a Go-No-Go gauge. If necessary, the ring can be removed with a decrimping tool.

The advantages of this method are:
1. This method is the most reliable and time-proven.
2. It is the only method which allows installer to check a completed connection for accurancy and redo it if needed. Waste of PEX fittings is virtually absent.
3. PEX Crimping method is the easiest and is suitable both for experienced installers and installers with little or no experience in the PEX industry.

The disadvantages of this method are:
1. A separate Crimp Tool is needed for every PEX tubing size.
2. PEX Criming Tool has to be calibrated every once in a while - usually, once per every plumbing project.
To solve the first issue, many manufacturers offer complete PEX Crimp Tool Kits, with interchangeable crimp heads.

A Decrimping tool is optional, as it will allow to remove the crimp rings from improperly done connections and will reduce the waste of PEX fittings.
Go-No-Go gauge is used to check the completed connections for accuracy and will indicated it tool needs to be calibrated.
Most common crimp-style fittings are brass crimp fittings, which are manufactured to ASTM F1807 standard. There are also plastic crimp fittings, made from polysulfone (PSU) or polyphenylsulfone (PPSU) and manufactured to ASTM F2159 standard. Both types can be used with Copper Crimp Rings.
Crimp rings are full-circle rings, manufactured from copper and are often coated with black powder for easy identification.

PEX Clamp (Cinch) style method requires a Clamp tool ("Cinch tool"), Stainless Steel PEX Clamps (Cinch Clamps) and Crimp-style PEX fittings.
Pictures are the tool itself and the clamp ring respectively:
PEX Clamp Tool / PEX Cinch Tool - Ratchet type. Stainless Steel Clamp / Cinch Clamp. ASTM F2098.

This is how a normal installation is done:
How to install PEX: Making a clamp (cinch) connection.
PEX tubing is cut to a required length, fitting is fully inserted, clamp is positioned 1/8"-1/4" from the end of pipe. Clamp tool jaws are fully opened and positioned over the tip of the clamp. The jaws of the tool are fully closed untill are released automatically by the ratchet mechanism.

The advantages of this method are:
1. There's only one tool needed for all PEX sizes (3/8", 1/2", 5/8", 3/4" & 1")
2. This method is virtually mistake-free.

The disadvantages of this method are:
1. Besides visual inspection, there's no way to check the connection for accuracy.
2. After prolonged use, calibrating the the tool can be very difficult.

Cinch clamps can easily be told apart from the ither type of PEX rings by a square-shaped tip, which is used to copmpress the ring over the pipe.
PEX Cinch clamps are manufactured to and marked with ASTM F2098 standard. Some hose clamps may look very similar, but the ones used for PEX tubing, always have "PEX" imprinted on the surface.
If needed, PEX cinch clamps can be removed by cutting the tip off the clamp ring and then prying the remainder with a flatbed screwdriver.

Common types of Radiant Heating projects

All radiant heating projects utilize Oxygen Barrier type PEX tubing as well as
Radiant Heat PEX Manifolds, Controls, Circulator Pumps and other components. Most radiant heat projects can be divided into the following main categories:
  1. Concrete Slabs (reinforced/structural slabs)
  2. Thin Slabs (non-structural slabs - gypsum, thermal mass)
  3. Snowmelt systems
  4. Staple-up installations (below subfloor)
  5. Engineered flooring installations (in-floor - sandwich type)
1. Concrete Slabs (structural slabs):
Installation of PEX tubing in a concrete slab.

(A): Wire mesh or rebars
(B): PEX Tubing of appropriate size
(C): Poured concrete slab
(D): Radiant Insulation
(E): Compacted base (gravel)

PEX Tubing installation in structural slabs refers to projects with concrete thickness 4-5" (sometimes 6"), where slab is reinforced with metal rebar or wire mesh. In such installations, PEX is secured on top of the reinforcement with zip ties or clips (metal wire ties not recommended). It is best to position the tubing half way in the slab, as it will assure best system performance and optimal heat distribution. The sizes of tubing used may vary depending on the heated area and project specifics.
Insulation must always be used in concrete slab installations to prevent the heat from sinking into the ground. Typical insulation types are: foam board insulation (such as extruded polystrene), bubble insulation and tarp insulation. Both tarp and bubble type insulation feature a vapor barrier and do not require additional installation of such. With foam board insulation, a vapor barrier is recommended to extend the life of the slab.

Installation of PEX in concrete slabs is common for ground level residential homes, as well as garages, warehouses and other comercial and manufacturing facilities.
Typical tubing runs are:
1/2" PEX: 300-350ft (the most common tubing size for residential and light commerical installations).
5/8" PEX: 400ft
3/4" PEX: 500ft
3/8" PEX tubing is not recommended for reinforced slabs and 1" PEX tubing is used only for facilities with very large areas.

2. Thin slabs (non-reinforced):
Installation of PEX tubing in a thin slab. Ceramic and tile radiant heat floors.

(A): PEX Tubing of appropriate size (usually 3/8" or 1/2")
(B): Grout
(C): Tile
(D): Thin set
(E): Thermal mass (gypsum concrete)
(F): Plywood

Thin slabs are common for kitchens and bathrooms - where there's tile or ceramic floors. Thin slabs are usually 1 1/4" to 1 1/2" thick, do not require reinforcement and are made of thermal mass (such as gypsum). Tubing is normally secured to the flooring surface using PEX rails, Snap-in PEX Clips or other appropriate type of installation accessories. Thermal mass is used for thin slabs for two main reasons:
1. It is ligher than regular concrete.
2. It has faster response time.
The use of thermal mass, however, increases the floor load, and may require modifications to existing joist system - consult with an engineer.
Tubing sizes used are 3/8" and 1/2". 3/8" is well suited for smaller areas (bathrooms), and, due to it's greater flexibilty can distribute the heat very efficiently. 1/2" PEX tubing, however, is still the most common and cost-effective size. Maximum allowable tubing runs can vary greatly depending on the climate, insulation and other factors.

3. Snowmelt systems:

Installation of PEX tubing for Snowmelt systems is very similar to one of a concrete slab. There are, however, several major differences:
1. Snowmelt systems generally require a larger tubing size (3/4" instead of 1/2").
2. Insulation is not required.
3. A proper drainage systems must be designed.
4. Antifreeze (propylene glycol) has to added (50/50 mix is common) to the water to prevent freezing. The loops with glycol mix are isolated with a Brazed Plate Heat Exchanger from the rest of the heating system.
Depending on the type of materials used for a snowmelt system (concrete, paving bricks, etc.), tubing size and spacing may vary.
3/4" Oxygen Barrier PEX is the most common for snow melting systems and the maximum tubing run should not exceed 330ft.

4. Staple-up (below subfloor):
Staple-up PEX installation method.

(A): Aluminum heat transfer plates
(B): PEX Tubing (usually 3/8" or 1/2")
(C): Joists
(D): Plywood

Staple-up method of PEX tubing installation is the 2nd most popular after slab installations. The use of Aluminum Heat Transfer Plates is recommended, as they allow for a more even heat distribution and lower the supply water temperature (thus lowering the heating bills).
In staple-up method, PEX tubing is secured to the bottom of the subfloor, parallel to the joist runs. The insulation is a must-have (although not displayed on the picture) and is installed right below the tubing with a 2" air gap between itself and the subfloor.
The insulation types used are: batt foil-faced insulation, bubble insulation, or combination of both. Crawl space installations may also require the use of a vapor barrier.

Purpose of the Heat Transfer Plates (fins) is to deliver and evenly distribute the radiant heat directly to the subfloor.
These are the most important factors of heat transfer plates are: 1. Thickness - the thicker the plate, the better. 2. Inner shape of the tubing channel - the smoother the channel is, the more contact the plate will have with tubing, thus delivering more heat.

Below are some common heat transfer plates shapes:
Types of aluminum heat transfer plates.

(E): U-shaped plates
(F): U-shaped double plates
(G): Reversed Omega-shaped channel plates
(H): C-shaped channel plates

U-shaped plates were the first ones in their class to be used for radiant heat transfer purposes. Both single (E) and double (F) plates must be installed at the same time as tubing. Double plates are designed to secure both supply and return tubing runs at the same time, however, we do not recommend the use of such plates since a supply line will always sink heat to the return line (instead of the floor). (E) and (F) types can also be used in conjunction with sleepers to improve heat distribution.
Reversed Omega-shaped and C-shaped channel are newer versions, which allow the installer to secure the plates first, and then conveniently snap in the PEX tubing (or hammer it in with a rubber maul).

Heat transfer plates are usually either extruded (better) or stamped, for 1/2" or 3/8" PEX tubing, and are supplied by manufacturers in 2ft, 4ft or 8ft lengths.

5. Engineered Floors
Engineered floors.

(A): Hardwood flooring (or floating floors such as laminate)
(B): PEX Tubing (usually 3/8" or 1/2")
(C): Floor panels
(D): Plywood/subfloor

Engineered floors (panels) are typically installed between subfloor (D) and finished flooring (A), which is why such installation type is called "sandwich". These panels are commonly manufactured from plywood by cutting layout channels for PEX tubing. Some are manufactured with built-in heat transfer plates, some can acommodate such.
Sandwich type installation can also be done by using "sleepers", which are pre-cut shapes of plywood, and laid out along the PEX tubing runs. They serve two main purposes:
1. To raise hardwood floors to a necessary height and allow for a proper PEX tubing installation.
2. To provide a layout channel for PEX tubing.

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