API 5L

As Lyn mentioned, if you are a provider of goods and/or services that are regulated by a Standard - owning/knowing/certifying to/performing to said Standard is imperative.

So API 5L is the standard for Line Pipe... that's what the 'L' stands for. There is also API 5CT (Casing and Tubing) which is closely related and as equally important.

I would recommend procuring both of them, and it just so happens that the host of this forums sells them. Look at the top most menu bar on this page... 4th from the left... "Standards Library" enter your key words into the search field and you can be on your way in minutes with a downloadable PDF copy of the standard.

Or, just follow this link:

https://global.ihs.com/doc_detail.cfm?item_s_key=00460775&item_key_date=991231&rid=GS

Now, if after you have acquire and read the standard - if you have specific questions or need assistance understanding a certain portion, please stop back and we'll be more than happy to assist.

You can purchase standards from IHS. For example, here is the API 5L spec.

There are many specifications under API 5L, here is a taste....

http://www.api.org/~/media/files/certification/monogram-apiqr/program-updates/api_5l_43rd_and_44th_ed_comparison_r1.pdf?la=en

Steel grade will be dependent on the process parameters.

The API is just the standard to follow.

Usually if there is a mention of inches like 18 inch this would be the nominal OD. Wall thickness should be something you are familiar with if you are dealing with pipe.

If not then ask Lyn to send you a pipe standard. The ID has to be smaller than the OD and the standard explains why.

Are you in procurement?

For pipe 14 inches and over, the given size is the actual OD (+/- tolerances). In your example, 18" OD and 0.5" wall = 17" ID.

Ideasmith, someone needs to read a standard to understand why an inside diameter needs to be smaller than an outside diameter ? If the inside diameter was larger than the outside diameter, then wouldn't the inside diameter then be greater than the afore measured outside diameter ?

Refer to the below standard then!

Sophia, here are some piping guidelines that you may find helpful.

#3 is very important!

1. All pipe is to be made of a long hole surrounded by metal or plastic centred around the hole.

2. All pipe is to be hollow throughout the entire length - do not use holes of different length to the pipe.

3. The ID (Inside Diameter) of all pipe must not exceed the OD (Outside Diameter) - otherwise the hole will be on the outside.

4. All pipe is to be supplied with nothing in the hole, so that water, steam or other stuff can be put inside at a later date.

5. All pipe should be supplied without rust; this can be more readily applied at the job site. NOTE: Some vendors are now able to supply pre-rusted pipes. If available in your area, this product is recommended, as it will save a great deal of time at the job site.

6. All pipe over 500ft (150m) in length should have the words "LONG PIPE" clearly painted on each side and end, so that the contractor knows it's a long pipe.

7. Pipe over 2 miles (3.2km) in length must also have the words "LONG PIPE" painted in the middle, so the contractor will not have to walk the entire length of the pipe to determine whether or not it is a long pipe or a short pipe.

8. All pipe over 6ft (1.83m) in diameter must have the words "LARGE PIPE" painted on it, so the contractor will not mistake it for small pipe.

9. Flanges must be used on all pipe. Flanges must have holes for bolts, quite separate from the big hole in the middle.

10. When ordering 90 or 30 degree elbows, be sure to specify left-hand or righ-hand, otherwise you will end up going the wrong way.

11. Be sure to specify to your vendor whether you want level, uphill or downhill pipe. If you use downhill pipes for going uphill, the water will flow the wrong way.

12. All couplings should have either right-hand or left-hand threads, but do not mix the threads otherwise, as the coupling is being screwed on one pipe, it is being unscrewed fron the other.

13. All pipes shorter than 1/8in (3mm) are very uneconomical in use, requiring many joints. They are generally known as washers.

14. Joints in pipes for piping water must be water-tight. Those in pipes for compressed air, however, need only be air-tight.

15. Lengths of pipes may be welded or soldered together. This method is not recommended for concrete or earthenware pipes.

16. Other commodities are often confused with pipes. These include: conduit, tube, tunnel and drain. Use only genuine pipes.

17. Scottish Regiments in the Army use Army pipes in unusual ways. These are not approved of in engineering circles.

Lyn, you keep giving answers away like that, somebody might nominate you for the " Good answer lifetime achievement award".

Never happen. I always make sure to balance the good answers out with an equal amount of snarkiness somewhere along the way.