Plumbing pipes are classified by their "nominal size" (approximate inside diameter) rather than their exact outside diameter. Standard residential sizes typically include 12 12 inch, 34 34 inch, and 1 inch for water supply lines, and 1.5 to 3 inches for drain, waste, and vent (DWV) systems.
1/2" pipe refers to the internal diameter, 15mm pipe is the external diameter... In my experience they are so similar that you can even use solder fittings without a worry, so using 15mm olives on 12" pipe isn't a problem. Occasionally they are very marginally tight, but not enough to be an issue.
The "135-degree rule" in plumbing states that the total (aggregate) horizontal change in direction for a drainage pipe—specifically trap arms—cannot exceed 135 degrees between the P-trap and the vent. Exceeding 135 degrees (such as using three 45-degree bends or a 90 and two 45s) requires a cleanout because sharp turns hinder flow and cause clogs.
PVC pipe 20 feet means the length of the pipe is 20 feet (about 6.1 meters). Pipes of this length are usually used as the main pipes in transportation, drainage, irrigation and other systems, and can play their unique advantages in many occasions.
3 Plumbing Pipe Materials You Don't Want In Your Home
Effects on Metal and PVC Pipes
While harmless for most metal and PVC pipes, prolonged exposure to the acidic nature of vinegar might corrode certain metals, like copper. PVC pipes, on the other hand, can withstand these substances without damage.
To protect your plumbing and the environment, you should never put fats, starches, harsh chemicals, or solid waste down your drains.
Here are the most common plumbing code violations you might not even realize you have—and why they matter.
Yes, a toilet and a kitchen sink can share the same main drain line, but they cannot tie into each other arbitrarily. Both fixtures ultimately empty into your home’s main sewer line. However, specific plumbing codes dictate exactly how this must be configured to prevent clogs and dangerous sewer gases from entering your home.
For residential plumbing, the most common water pipe sizes are 12one-half𝟏𝟐-inch, 34three-fourths𝟑𝟒-inch, and 11𝟏-inch. The ideal size depends on the specific job within your plumbing system.
When shopping for a toilet supply line, the 3/8-inch size is the modern standard for residential shut-off valves, while 1/2-inch is usually reserved for older, existing plumbing. For the toilet end, however, both require the exact same 7/8-inch connector to attach to the fill valve under the tank.
For most residential plumbing, use 1/2-inch PEX for individual fixture supply lines (sinks, toilets, showers) and 3/4-inch PEX for main trunk lines, water heater connections, and high-demand areas. A 3/4-inch line should run from the main source, branching off into 1/2-inch lines for each fixture.
Plumbing pipes are sized by their Nominal Size (an approximate measurement of the inside diameter), not their actual physical width. To find the right size pipe or replacement fitting, measure the Outside Diameter (OD) using one of the two methods below and match it to a sizing chart.
With modernisation these imperial fittings have now been given a metric name, but they are the same thread spec. So a 3/4 fitting is now also called 20mm. 1/2 inch fittings are now also called 15mm. The 15mm or 20mm is not the size of the threads, it's still the ID of the pipe.
15mm (1/2") Type B Copper Coil Annealed x 18M | Forge Plumbing Australia.
PMRs for malignancies of the stomach, kidney, brain, and lymphopoietic system were also elevated, especially among plumbers. Chronic rheumatic heart disease, emphysema, liver cirrhosis, and all external causes of death were the major non-cancer causes with significantly elevated PMRs.
The "135-degree rule" dictates that a cleanout (an access point to clear blockages) must be installed in a horizontal drain pipe every time the cumulative turns exceed 135∘135 raised to the composed with power𝟏𝟑𝟓∘.
However, recent failures and the lawsuits that have followed those failures lead to the idea that PEX plumbing systems aren't as good as once assumed. PEX systems can fail in either the pipe or in the fitting. The most notable failure occurs when the fittings fail and water starts leaking and causing visible damage.
Pouring salt down your drain at night is a popular DIY plumbing trick used for routine maintenance. The goal is to take advantage of the salt's coarse texture and natural moisture-absorbing properties.
Generally, you should only flush toilet paper and your body's waste. Water and anything typically mixed with water, such as toothpaste, soap, and shampoo, are the only products that should go down our sinks and shower drains.
A straightforward yet effective approach to addressing a clogged drain pipe involves simply using hot water mixed with dish soap. This method, ideal for tackling minor blockages, leverages the degreasing power of dish soap combined with the force of hot water to dislodge and dissolve clog-causing residue.
Pouring boiling water down your drain can soften and warp PVC pipes, weaken the glue in pipe joints, and damage rubber gaskets. Instead of clearing grease, boiling water just melts it, pushing it further down the pipe where it hardens and creates a stubborn, hidden clog.
Baking soda and vinegar do not effectively unclog drains. Instead of clearing debris, mixing them chemically neutralizes both ingredients into salt water. The fizzing reaction is visually satisfying but largely escapes upwards, offering zero power to dissolve grease, hair, or stubborn sludge.
While white vinegar is an excellent natural cleaner, its acidity means it can damage certain surfaces, strip finishes, or cause rust. You should generally avoid using it on: