Gas Pipes and Fittings FAQ’s Q. What is PEX-AL-PEX? A. PEX-AL-PEX is cross-linked polyethylene. Through one of several processes, links between polyethylene molecules are formed to create bridges (thus the term "cross-linked). This resulting material is more durable under temperature extremes, chemical attack, and better resists creep deformation, making PEX-AL-PEX an excellent material for hot water and other applications. HOWEVER only piping marked to LPGas may be used and the ASTM 1282 explains the markings required on the piping. Therefore the plumbing white piping may not be used for gas applications. Internationally YELLOW is used for gas piping. Q. How long has PEX-AL-PEX been used? A. PEX-AL-PEX was developed in the 1960s. PEX-AL-PEX tubing has been in use in many European countries for plumbing, radiant heating and snow melt applications since that time. PEX-AL-PEX was introduced in the United States in the 1980s, and has seen significant growth in market demand and production for various applications. Q. What are recommended uses for PEX-AL-PEX? A. PEX-AL-PEX's flexibility and strength at temperatures ranging from below freezing up to 200 degrees Fahrenheit makes it an ideal piping material for hot and cold water plumbing systems, service lines,  hydronic radiant heating systems, snow melting applications, ice rinks and refrigeration warehouses. Q. Why is PEX-AL-PEX an excellent piping material for plumbing and gases? A. PEX-AL-PEX is ideally suited for potable water and fuel gases applications. It is flexible, making it easy to install and service. PEX-AL-PEX is able to withstand the high and low temperatures found in plumbing and heating applications, and is highly resistant to chemicals found in the industry environment. Flexible systems are quieter than rigid piping. The smooth interior will not corrode which can affect other materials long term pipe flow characteristics. PEX-AL-PEX is also very freeze- break resistant. PEX-AL-PEX systems have fewer joints and are easier to install providing a lower cost installation over traditional steel and copper materials. Q. How can I be sure that PEX-AL-PEX is a safe product for gas use? A. PEX-AL-PEX is manufactured and tested according to stringent national consensus standards: ASTM F 876, F 877, AWWA C904 and CSA B137.5 and as4176.Both the product manufacturer and independent third party testing agencies conduct routine quality control and quality assurance evaluations to insure the product meets ASTM, ANSI/NSF International and CSA Standards. Compliance with the standards ensures the end user of safety and quality. Additionally, PEX-AL-PEX is included in all of the major model plumbing codes used in the United States , Australia and Canada; NPC, UPC, IPC and NSPC, and approved by HUD for hot and cold potable water plumbing and gas use. Q. Where is PEX-AL-PEX approved for use? A. PEX-AL-PEX is an approved material in all the current model-plumbing codes; however, some jurisdictions using older versions of these codes may not have amended the code to include PEX- AL-PEX tubing. Contact the local authority and the LPGas safety Association to verify the acceptance of PEX-AL-PEX tubing for LPGas vapour applications in your area. Q. Can PEX-AL-PEX be used under the slab? A. Yes. The flexibility of PEX-AL-PEX allows it to be supplied in coils meaning installations under the slab can be made in a single, continuous length without the need for fittings. PEX-AL-PEX is not affected by concrete, (it is commonly encased in concrete for radiant floor heating). Q. Can PEX-AL-PEX be used for commercial service applications? A. Yes. Although the high temperature resistance of PEX-AL-PEX makes it particularly suitable for hot and cold plumbing applications, it also excellent reticulation gas service piping. It has proven itself as extremely robust due to the aluminium layer. Under tests it was found to be less prone to leaks when abused due to the PEX layertrengths.PEX-AL-PEX can be installed using the same fittings recommended for copper tube sized SDR-9 polyethylene tubing. Q. Can PEX-AL-PEX be used for aboveground outdoor applications? A. YES , but must be protected from direct sunlight with sleeving. Short exposures to sunlight during construction are permissible, but should not exceed the manufacturer’s recommendations. PEX- AL-PEX should be stored under cover, shielded from direct sunlight or in the original packaging. In the future, PEX-AL-PEX products rated for outdoor use may be developed.  Q. Can PEX-AL-PEX save me money? A. Yes. PEX-AL-PEX saves money in many ways. For the installer, Q. What joining systems are available? A. There are several methods of connecting PEX-AL-PEX, all of which involve mechanical fittings. However the use of mechanical fitting are not allowed for underground or imbedded use. The crimp fittings specified in ASTM F1807 are the most widely used for embedded use. Other fitting systems, including insert and outside diameter compression fittings, are also available, but are not allowed is South Africa for gas use. Q. How long can PEX-AL-PEX be exposed to sunlight? A. PEX-AL-PEX tubing is not intended for outdoor applications and must be stored in a covered environment not exposed to direct sunlight. Refer to manufacturer’s instructions as to how long your pipe can have UV or sunlight exposure. Q. What are temperature limitations for PEX-AL-PEX? A. PEX-AL-PEX tubing can be used up to 95° degree for heating applications. Temperature limitations are always noted on the print line of the PEX-AL-PEX tubing.. PEX-AL-PEX systems are tested to and can be used with standard gas appliances ,but are limited for the use inside the fireplace boxes. Q. How are PEX-AL-PEX systems tested for leaks? A. Standard pressure testing using gas , nitrogen and air are mostly used. The PEX-AL-PEX piping and crimp fittings has been tested in SA to 80 Bar and also certified internationally to that level. Q. How soon after installation can you pressure test a PEX-AL-PEX tubing installation? A. PEX-AL-PEX plumbing systems can be tested immediately after the installation is complete but follow manufacturer’s directions.. There is no wait time for glue to dry or joint to cool off. Manufacturer's instructions should be followed in cold climates. Q. Where is PEX-AL-PEX available? A. PEX-AL-PEX is available through most gas wholesale distributors throughout South Africa. The white piping supplied to plumbing outlets may not be used and will fail under gas use. Piping and fittings are commonly available in ¼” and sizes up to 1” also supplying larger sizes up to 2." Because the wall-thickness is proportionate for each size, the pressure ratings are the same for all sizes. Q. What sizes, lengths and packaging options of PEX-AL-PEX are available? A. PEX-AL-PEX is available in 1/4" through 1" and is packaged in coils of 200 to 100 m. Some manufacturers tubing is color-coded for easy identification of LPGas use. Q. What are manifold plumbing systems? A. Manifold, parallel or home-run plumbing systems are much like a breaker box for the electrical system in the home. The manifold provides a common location from which all the gas appliances are supplied. Some high-end manifolds also feature fixture shut-off valves allowing the user to shut off the gas to individual appliances from one location. Q. How are PEX-AL-PEX systems sized? A. PEX-AL-PEX systems are sized using both the inner and outer diameter of the piping. For example, the 1216 piping is 12mm inside diameter and 16 mm outside diameter. Therefore the piping sizes are: 1014, 1216, 1620, 2025, 2532, etc. Q. Is the thermal expansion/contraction of PEX-AL-PEX a problem? A. No. PEX-AL-PEX expands less than other plumbing materials, due to the aluminium layer within the composite pipe structure. It only expands 59.6 mm ofer a 50 meter length at 50 degree Celcius. Q. Can PEX-AL-PEX be joined with solvent cement? A. No. PEX-AL-PEX cannot be joined with solvent cement, glues or heat fusion. PEX-AL-PEX is installed using only mechanical fittings or compression fittings. When applying heat for electrofution the HDPE melts away well before the PEX-AL-PEX reaches melting temperature.