First lets talk about water piping:
[h=3]Copper Pipe[/h]
This type of pipe is mostly used for hot and cold water distribution as well as being regularly used in HVAC systems for refrigerant lines. Copper piping works in both underground and aboveground applications, but copper can be affected by some soils and should be sleeved if used underground. Due to the price of copper and longer labor needed to install many builders are switching to alternative water distributions piping like PEX. Copper comes in different thicknesses which are labeled M, L, and K. M is the thinnest grade of copper. Copper is connected by soldering pipe into the fittings.
[h=3]PEX[/h]PEX stands for Cross-linked polyethylene or XLPEl but, PEX is much easier to remember and say. PEX is commonly used for hot and cold water in homes and as hydronic heating due to its resistance to hot and cold temperatures. PEX is widely used now for its competitive pricing, ease of use, and the long rolls of piping that it can come in. PEX is jointed in many different ways including push fit fittings and specialty PEX tools used with crimp rings to secure the joints.
[h=3]PVC[/h]PVC stand for PolyVinyl Chloride. This type of pipe has a wide variety of plumbing uses from drainage pipe to water mains. It is most commonly used for irrigation piping, home, and building supply piping. PVC is also very common in pool and spa systems. PVC is often white but it can also come in a wide variety of colors. You can often tell what it is used for by the colors and marking on the pipe. For example purple pipe with black lettering is used for reclaimed water. PVC also comes in a variety of thicknesses called schedules. Schedules 40 being the most common for water distribution.PVC pipe should always be clearly labeled if it is used for both potable (drinkable) and non potable water in the same building. PVC joins are made by using a primer that softens the PVC and then applying PVC glue that melts the joints and pipe together.
[h=3]CPVC[/h]CPVC stands for Chlorinated Polyvinyl Chloride. This type of pipe can stand temperatures up to about 180 degrees (this depends on the schedule) or so and can be used for hot and cold water inside of a house or mobile home. CPVC is the same outside diameter as copper and PEX so push fit fittings that fit PEX and copper, such as SharkBite, will fit the CPVC pipping. Like with PVC you should use primer and a glue when making a CPVC joint. Also, make sure the glue you are using says that is can be used on CPVC. This glue is usually a different color like orange so you know that it is used for CPVC.
Now lets talk about gas piping:
Copper tube is what is normally used.
[h=3]PVC Pipes[/h]PVC - Polyvinyl Chloride - pipes may be used in pipelines buried outside a building.
[h=3]PE Pipes[/h]PE - Polyethylene - pipes may be used in pipelines buried outside a building.
[h=3]Flexible Connectors[/h]Flexible connectors are used to connect appliances to gas sources. Flexible connectors must be approved.
[h=3]Copper Pipes[/h]Copper pipes used in gas systems should be of type L or K and approved for gas.
[h=3]Yellow Brass Pipes[/h]Yellow brass pipes may be approved for inside installations.
[h=3]Aluminum Pipes[/h]Aluminum pipes should not be used in the ground. Aluminum is not approved in all jurisdictions.
now lets talk about Mass and Weight :
Well, mass is a measurement of how much matter is in an object; weight is a measurement of how hard gravity is pulling on that object.
Your mass is the same wherever you are--on Earth, on the moon, floating in space--because the amount of stuff you're made of doesn't change.
But your weight depends on how much gravity is acting on you at the moment.
And when i say "maximum weight" i mean the maximum weight that the object can support before breaking, not the mass of the object.
there is a max weight in everything!
Mass versus weight - Wikipedia, the free encyclopedia
Weight - Wikipedia, the free encyclopedia
What is WEIGHT? definition of WEIGHT (Science Dictionary)
http://web.eecs.umich.edu/~pettie/ma...al-version.pdf