What Size Does Cast Iron Drain Pipe Come In

Pipe Sizing Explained

When it comes to sizing piping, there are a few considerations for how to do it and why it matters:

How big is the hole the textile will go through?
How far is the material going?
How thick does the wall of the pipe need to be?
What factors are working against the system (friction, possibility of erosion, etc.)?

The pipe needs to exist the proper size to handle what it'southward carrying (h2o, gas, air, drainage, etc.), but it also cannot exist likewise small-scale, or it could crusade the volume to travel likewise fast. And that could cause serious problems, such as water hammer (a hydraulic shock or pressure level surge), which in turn could impairment the pipe organization and the fixtures attached to the piping.

Days Gone By

Determining pipe sizes can be somewhat disruptive, primarily because of the historical method of sizing and the fact that some electric current sizing notwithstanding refers to those legacy systems. Have this instance:

Years ago, a one-half‐inch pipe had an inner diameter of 1/ii inches. It also had thick walls, as that was the manufacturing standard at the time.

Over the years, improved applied science has enabled the walls to be thinner while retaining the same capabilities. However, to lucifer up with existing (larger‐walled) pipe, the within diameter of the new pipe had to be larger.

Which means the pipe was not 1/ii inches, no matter which way you measured.

When mass production of pipe began, there was a need for standardization. In 1927, the American Standards Clan – which has since evolved into the American National Standards Establish (ANSI) – convened a committee to standardize the dimensions of wrought steel and wrought iron pipe and tubing. Dorsum and then, simply a few wall thicknesses were used: standard weight (STD), actress‐strong (XS), and double extra‐strong (XXS), based on the atomic number 26 piping size (IPS) system of the twenty-four hours.

By 1939, schedule numbers were starting to come into use, but the original terms stuck and are often still used today, though XS and XXS were revised slightly to extra‐heavy (XH) and double extra‐heavy (XXH), respectively.

By the 1950s, stainless steel was coming into use more frequently, allowing the use of thinner pipes (eastward.yard., 5S and 10S), which were based on pressure requirements. (Information technology is worth noting that because of their thin walls, the smaller "Southward" sizes cannot be threaded merely must be fusion welded.)

Alphabet Soup of Pipe Metrics: IPS, DIPS, NPS, CTS

If the legacy of sizing isn't confusing enough, consider that pipes take been sized differently over the years depending on the specific sizing system:

Iron Piping Size (IPS) — sized by reference to the inside diameters; the standard from early 19th century through just subsequently Globe State of war Ii; yet used in PVC manufacturing and steel gas and water piping
Ductile Iron Pipe Size (DIPS) — similar to NPS only used for larger pipes
Copper Tube Sizing (CTS) — in the 1920s, this was combined with the IPS standard; the inside diameter is measured in the "types" (G, L, and 1000 for thinnest, thicker, and thickest, respectively)
Nominal Pipe Size (NPS) — outside bore is fixed for a given pipe size and inside diameter varies depending on the wall thickness (referred to as "schedules")
Plastic Irrigation Pipe (PIP) — used in agricultural applications; comes in pressure ratings (psi) and is available in diameters from 6" to 24"

NPS is the N American standard today. The electric current practice is to decide pipe size through two numbers: ane) the pipe bore (or diameter) and two) the pipe schedule (or wall thickness) – though these two numbers can exist configured in slightly different ways depending on the specific pipage used.

NPS sizes are documented past a number of standards, including API (American Petroleum Institute) and ANSI/ASME (American Guild of Mechanical Engineers).

The most common pipes used today are:

Cast fe — more often than not in use before 1960; used for bleed/waste/vent (DWV) lines
Steel (galvanized piping) — common in older homes; lasts only nigh 50 years
Plastic — used since mid‐1970s; two types:

ABS (acrylonitrile‐butadiene‐styrene) — blackness color; commencement to be used in residential homes, though some areas restrict their utilize in new construction
PVC (polyvinyl‐chloride) — white or cream color; rating and diameter are stamped on the pipe; a few notes on PVC:

Schedule 40 PVC is strong enough for drain lines and cold‐water lines, but local code volition decide applicability. When used for common cold‐water lines, it is generally not allowed for utilize inside a edifice
Schedule 80 PVC is often used for cold water lines just isn't allowed for use inside a building in some areas because it isn't suitable for hot water
CPVC (chlorinated polyvinyl chloride) is as stiff every bit PVC but is estrus‐resistant, which makes it acceptable in most areas for interior supply lines; it is most commonly measured with CTS standards (which is important when considering fittings for existing piping; for instance, a two" fitting will non e'er fit on a 2" CTS pipe, simply it will always fit on a ii" nominal size PVC pipe). Schedule 40 and fourscore CPVC pipe and schedule 80 CPVC fittings are available and by and large used in industrial applications

Copper — commonly used in h2o lines and some drain lines; resists corrosion, lasts a long time

Rigid Distribution Pipe — comes in iii thicknesses: blazon Thou (thinnest), type 50 (thicker), blazon Thousand (thickest)
Rigid Drain Pipe — comes in ane thickness Marked DWV and is thinner walled than type M
Flexible (soft) — often used with appliances lines (due east.yard., dishwasher, refrigerator, icemaker) and rolled out for under slab installations

PEX (cross‐linked polyethylene) — newest pipe for residential employ; easy to install (cuts hands, is flexible); it tin can employ compression fittings or push on fittings, more permanent connections require crimp manner fittings and a crimping tool

Computing Pipe Size

Pipe Sizing Charts

Knowing the background on how and why the sizing is determined is critical, though yous volition non necessarily demand to resort to advanced math to figure it out. Fortunately, in that location are tables for every type of pipage that is canonical for h2o service and distribution. These charts are used to make up one's mind pipe size that will deliver the amount of water and at the force per unit area needed to operate a plumbing system that uses a variety of common household fixtures and appliances.

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