PVC primer and glue

baymeeJuly 6, 2008

What's the difference between the purple and clear versions of the primer? Both claim to be for PVC with no mention of pressure (house water) or no pressure?

Also, it says to wait 24-48 hours before applying pressure. How does a plumber make a repair and turn the water back on again?

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pvc is for drain's not supply of water........... it will hold a lot of pressure..................... there is a pressure reading on the pvc. why would you use pvc to supply water.

    Bookmark   July 6, 2008 at 7:04AM
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There are two types of PVC. DWV PVC which is for drains and Pressure rated PVC for potable water. We use PVC to convey water all the time. But you need to make sure its pressure rated.

To answer your question, there really the same thing. They both are good primers. A lot of inspectors want to see purple primers so they know that the piping was installed correctly. I use clear primer when I am setting out on a new build just in case I drop some on the floor. The purple primer will never come up.

Depending on the size of the pipe you are glueing is how long you have to wait untill applying pressure. Im guessing you have 3/4 inch lines in your home, maybe 1". Wait a good hour or so for the glue to dry before turning the water back on.

    Bookmark   July 6, 2008 at 11:25AM
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Yes, it's all pressure rated PVC, both 3/4 and 1". Thanks for the tip on the waiting time.

    Bookmark   July 6, 2008 at 11:38AM
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Radiantman08's statement, "Pvc is for drain's not supply of water" is not correct.

PVC is approved for water "Supply piping", which is the direct buried underground line from the municipal water main or well to the structure. PVC is not approved for "Distribution Piping", which is the water supply piping within a structure.

PVC (Schedule 40 only) is approved for DWV (Drain,waste & vent) and house sewer piping.

ASTM (American Society of Testing & Materials( specifications require that we must use primer before applying glue on PVC pipe.

Both the clear & purple primer are exactly the same product however for new construction many codes require we use the purple primer, which has the dye added so an inspector can be insured that primer was used prior to gluing.

The act of gluing PVC is not really gluing. When you glue something you apply a product that adheres to the surface of both pieces and provides a filler material between the pieces. Technically speaking, the method of joining PVC should properly be called "Chemical Welding". The primer cleans the contact surfaces of both the pipe & fitting and it chemically removes the smooth glazed finish of the PVC exposing the inner core material. The Glue then melts the inner core material of both the pipe and fitting and both the pipe and fitting are fused together into one solid mass. As the two materials fuse together they will achieve approximately 90% hardness within the first hour but it takes 24 hours to achieve 100% hardness. For reasons of product liability the manufacturers state the product must stand for 24 hours before applying pressure but in the real world very few customers would be willing to pay a plumber to stand there 24hours watching the glue dry, therefore most plumbers rely upon the 80% hardness 5 minute or 90 % hardness at 1 hour to be sufficient to restore the water pressure. This is not meaning to say that it is totally technically correct, but it has become an industry accepted shortcut.

    Bookmark   July 6, 2008 at 11:59AM
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Thanks for the in-depth reply.

A trip to the hardware store or the box store reveals a dizzying amount of small sized pipes and fittings in PVC and CPVC. I know these are meant for plumbing water throughout the house.

So, how does "not approved for distribution piping" pvc work in the real world where it is prevalent in many houses and a huge seller at the store?

    Bookmark   July 7, 2008 at 11:22AM
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QUESTION: If PVC pipe is no longer approved for plumbing water distribution piping within a structure why do they carry such a wide variety of PVC pipe & fittings in the local hardware or home supply store?

ANSWER: First of all, it must be understood that the retailer must keep an inventory to meet the demand of their entire customer base whereas, both residential and commercial plumbing only represent a small percentage of the total overall customer base of the hardware retailer, by example,
1. Landscaping Contractor generally select PVC as the material of choice for landscape irrigation systems.
2. Swimming Pool contractors use PVC as the material of choice for installing pool-filtering equipment.
3. HVAC contractors use PVC for AC condensate drains, Combustion air intakes and on direct vent furnaces they use it for the exhaust flue.
4. Electricians use PVC for electrical conduits.
5. Farmers use PVC for conveying liquid fertilizers, running temporary water lines to remote stock watering tanks or conveying liquefied manure.
6. PVC has thousands of uses in the industrial environment such as conveying lubricants, process water or brine solutions and in some instances raw materials related to the production at hand.
7. In the Food Processing Industry they use a tremendous amount of PVC for conveying both liquid and dry ingredients from bulk storage to the processing vats or from the vats to the canning or bottling process. In fact, the food processing industry is the prime consumer of clear PVC pipe.

As you can see, the hardware dealer has no way of knowing what end use application the customer is intending for the products they sell. It is the sole responsibility of the installer to know what products they may or may not use, in fact even though code now prohibits installing PVC in the house potable water distribution system, under certain conditions a Plumber or Maintenance man/woman may be required by code to install PVC in your house when performing "maintenance" on your potable water distribution system. Does that seem a bit confusing to anyone? Allow me to explain:

In most jurisdictions the codes state that a homeowner or his/her delegated maintenance man/woman may perform "Maintenance" without pulling a permit. In addition, a homeowner may pull a self-help permit to perform "Plumbing" providing the plumbing is to be installed in a single family dwelling, which is used exclusively as the principal domicile of the homeowner & his/her immediate family. It is further understood that when a homeowner pulls a self-help permit he/she will be required an inspection and they will be held totally responsible for full code compliance of all work performed.

As you can see, the question then becomes, what is "Maintenance" and what is "Plumbing"?

It is assumed by the code that the initial installation was inspected during the installation process and it met all applicable codes in force at the time of the installation By legal definition "Maintenance is the act of maintaining an existing system in its original configuration including all pipe, valves, fixtures and appurtenances" and thereby it is grand-fathered by the original installation code, permit & inspection.

As an example, let us assume for the moment that you bought a house, which was constructed in the late 60s or early 70Âs when PVC was approved for potable water distribution and your entire layout is PVC. In this case, by legal definition if one of those PVC lines were to fail you may replace it with PVC as an act of Maintenance and not violate any code or require any permits or inspections.

On the other hand, if you were to remove the defective PVC line and replace it with Galvanized Iron Pipe, Copper, CPVC, or PEX that would legally be defined as an act of Plumbing because you are altering the original design in which case you would be required to pull a permit and all valves, piping, fixtures and appurtenances downstream from the point of transition from the original PVC pipe would be required to be upgraded to current code approved materials and all work would be required to be inspected prior to use.

As you can see, while the codes prohibit PVC for new construction, if the original distribution system was installed with PVC we are required to use PVC to repair it.

    Bookmark   July 7, 2008 at 4:15PM
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Why was PVC use halted in the first place?

    Bookmark   July 9, 2008 at 11:15AM
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"Why was PVC use halted in the first place?"

I believe it's a reliability issue. While rare, there is a greater likelihood of properly installed PVC failing than say properly installed copper tubing.

Perhaps it has something to do with the possibility of the pipe being hit. I know it's possible to shatter a piece of PVC if it is hit just right. Hence, when you carry a bundle of PVC pipe, you have to make sure the pipes don't slap against each other.

    Bookmark   July 14, 2008 at 1:17PM
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