Saw this in an old collection of rec.humor.funny stuff yesterday.  This version comes from here.

1.1 All pipe is to be made of a long hole, surrounded by metal centered around the hole.

1.1.1 O.D. of pipe must exceede the I.D., otherwise the hole will be on the outside.

1.2 All pipe is to be hollow throughout the entire length.

1.2.1 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.

1.3 All pipe is to be of the very best quality, perfectly tubular or pipular.

2.1 All acid proof pipe is to be made from acid proof material.

3.1 All pipe is to be supplied without rust, as this can be more readily be applied at the job site.

3.2 All pipe is to be cleaned free of any covering such as mud, tar, barnacles, or any form of manure before putting up, otherwise it will make lumps under the paint.

4.1 All pipe over 500 feet long will have the words LONG PIPE clearly painted at each end so the fitter will know that it is a long pipe.

4.1.1 Pipe over two miles long must also have the words painted in the middle so the fitter will not have to walk the full length of the pipe to determine if it is a long pipe or not.

4.2 All pipe over six inches in diameter is to have the words LARGE PIPE painted on it so that the fitter will not use it for small pipe.

5.1 All pipe closers are to be open on one end.

6.1 All pipe fittings are to be made of the same stuff as the pipe.

6.2 No fittings are to be put on the pipe unless specified. If you do, straight pipe becomes crooked pipe.

6.3 Fittings come in all sorts of sizes and shapes. Be sure to specify the direction you are going when ordering.

6.4 Fittings come bolted, welded or screwed — always use screwed. They are best.

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

7.2 If the flanges are to be blank or blind, the big hole in the middle must be filled with stuff.