What Proper Drill Tool Necessary to Make Hole in a Pipe

Cutting torch and a steady hand.

cutting torch and a steady hand. properly sized pipe, with the end cut in a saddle shape, to mate with the target pipe... use this as a guide...

Chris

i take it b,i is black iron ??

http://www.google.co.uk/search?q=drilling+B.I.+Pipe&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=iiyWTNS-Gtm5jAfO7dikBQ

http://www.google.co.uk/search?q=snap+cutter+cast+iron+pipe&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=mC2WTOepBYOQjAf7zZClBQ

Hot tapping on a pressurized pipe.

And you are asking us for info on how to drill?

Any questions about safety?

Just wondering.

Bless you.

Milo

Yes on a 4 inches pressurized pipe. Actually our hot tapping tool is ok. However our problem is that our hole saw seems have aproblem so I am thinking another way of hot tapping a 4 inches hole on a black iron pipe sch. 40 (3/16 " thick). Maybe you have some drill tools for a 4 inches size.

There is a company named Mueller Canada they sell hot tapping tools and special saddles. you thread a main stop into the saddle and the tapping tool threads onto the main stop. you turn the tapping tools cutter till it is through the pipe then reverse the direction once the cutter is free you can turn off the flow using the main stop. disconnect the tapping machine and you have a valve controlled hot tap.

I'd comment, but I've been accused of being insensitive.

Flashlight and Zippo_{(no endorsement)} is where I'd go.

Your problem is probably due to lack of lubrication on the hole saw teeth and not an aggressive enough feed rate of the hole saw into the pipe. Just as when cutting the pipe on a band saw, the blade and pipe must be flooded with oil to keep the blade cool, flush chips, and to lubricate the metal to metal contact points so the teeth can cut the pipe.

Don't know what your hot tap set-up is so I can not suggest a direct solution to your problem. You have to find a way to get oil on the hole saw at the pipe.

Good Luck, Old Salt

Thanks to your comment. I have considered this already however the pressurized line is critical of quality compressed dry air which may contaminate the line. Maybe at the start we will consider this.

Never heard of a full line size hot tap (4 inch on 4 inch).

Wonder what the material in the pressurized pipe is - flammable or not?

I think this is the very problem of OP – airmek.

If a 4" (split) Tee is welded to 4" pipe and the suitable cutter (or hole saw), theoretically it may be possible. Practically the inner cut piece may not get separated when the depth of cut is carefully stopped at the centerline of pipe. The danger of surpassing the centerline is that, the cutter might eat into the Tee fitting.

The only way I could think of is to use bigger Tee fitting, say 6" Tee and run the cutter slightly beyond the centerline. Of course, you may have to use (split) reducers as well on either end of the Tee.

That's the way it should be done. He'll have to cut any flow though. GA

The picture illustrates exactly what we are doing right now. In our case we use hole saw instead of a cutter. Can you suggest sites where we can buy a 4 in. and 3 in. hole cutter with a depth of at least 2 in.?

As to the saddle for the gate valve, we just did an equal split clamp bolted together with a gasket in the saddle clamp. It is very risky for a pressurized pipe to weld. We have not taken measurements on the thickness of the pipe since it is an old one but it is a schedule 40 B.I. Pipe.Did you really weld the fitting to the pipe considering the pressure inside the pipe is 150 psig? We are afraid it may soften the wall of the pipe during the welding since the pipe is active and pressurized. Hope you can share your technique.

Thanks for the very illustrative comments.

What you are talking about doing now is far more risky than welding on a pressurized line.

In the real world when you are doing a hot tap on a hydrocarbon line that line is normally pressurized at far-far more than 150 lbs - that is only about 10 barg.

If your welder is concerned about welding on a pressurized line you should look at hiring a different welder for the job.

To perform a hottap process, and to avoid overheating of fluid inside the pipe and adjacent to the pipe welded portions, you have to adjust the fluid (liquid or gas) flowrate to control the velocity of the fluid to be within the limits defined by the code of API 2201 "Procedures for Welding of Hot Tapping on Equipment Containing Flammable".

You can free download the following PDF file Hot_Tapping and look how we calculate the required fluid velocity during welding for hottaping process.

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The pipe contains air - a very different world.

Can you weld the flange on then use the interior of the flange as a guide for the hole saw "cutter"? If not, can one be clamped on temporarily as a guide?

Cutting a hole in the side of a pipe does present problems for the mechanic. during the first part of the cut - the correct amount of cutting teeth are in contact with the metal, then it starts to vary. At some point you will have 4 cutting surfaces at one time. A guide (either permanent or temporary) would be helpful.

Why not keep it simple

Six-bolt flanges are things of great wonder and frustration unless they are slip-on ones. Most drawing offices have only 45deg set-squares. Then along came CAD....

I assume that this is a one-off job and not something that is going to be mass produced...........I guess one could always use a protractor.........or even use geometric construction for angles.........whoops, I forgot........... they probably don't teach that now in basic engineering drawing.

A ring of Thermite maybe? Make sure it is under full pressure and film the procedure. Could be a hit on you tube.

I've publicly sworn off nuclear weapons for the Transcendian arsenal. Hence I cannot join NATO in good conscience.

Anyway I think Milo and Ky have focused on some significant safety issues if what the OP writes is correct.

If you think you will not interrupt the flow of the gas, whatever, that is underpressure, drilling holes in pipes is not your main problem.

Apparently you do not know that doing things out of order is a recipe for disaster.

In electrical situations I may create a "bypass" by running wires around a problem to kill it dead before I fix it, or replace it.

If there is smoke there is usually fire.

Your best solution is to drill a 3-inch hole with a 3-inch hole saw in the 4-inch main but use a 4-inch branch with appropriate packing downstream of the 4-inch gate valve.

No matter WHAT your product, the pressure drop triggered by the 3-inch hole will be essentially negligible- it will be like a very large orifice.

The problem you are running into trying to cut a full-sized hole is that you are cutting totally through not only the thickness of the main pipe, but also through the full side wall. The 3-inch saw will ONLY cut wall thickness and will be lubricated as soon as the pilot hole drill guts through the main pipe wall (assuming that the main is full of fluid). If the main is filled with pressurized gas, then some lubricating fluid should be flushed through the branch as well.

energygod is right. Drill a smaler size hole, otherwise you will face huge problems doing the hot tap with a 4" branch on a 4" main run.

If you have the drill ( cutting piece ) exactly at the inner diameter of your pipe, how are you going to control the depth of the hole at exactly 1/2 of the 4" main run (to not go deeper and to cut also from the wall of the pipe that is supposed to remain there - supposing that the hole is drilled vertical down, the bottom half of the pipe)?

Also, think what is happening when you have an offset of center of your hole with regard to the center of the pipe- how are you controlling the offset and with what accuracy are you doing this one in the filed ( I am supposing that you are doing the hot tap in the field ).

GA.

The standard under pressure drilling machines used in the UK and Europe use ordinary Steratt type Hole saws as the cutter on a special mandrill running in bearings through gas tight glands. I have ordered and witnessed the installation of hundreds of these over the years (far to many to count) and the largest hole is always one size down from the nominal size of the pipe to be drilled otherwise you end up trying to drill the strength out of the pipe wall.

The company I worked for did from 1 1/2" of 2" at 8"wc up to 30" of 36" at 1000psig line operating pressure by welding a split saddle tee onto the main to be tapped, fitting a full bore plate valve, pressure testing to 1250 psig, dropping the line pressure and drilling through the plate valve, initially with a 6mm pilot drill and then with the hole saw on a disk retaining mandrill.

Regards,

Gasman

You are the right person for OP's very question, 4'' tapping on a 4" pipe and not the question of Hot Tapping...

You have said, "have ordered and witnessed the installation of hundreds of these over the years (far to many to count) and the largest hole is always one size down from the nominal size of the pipe to be drilled otherwise you end up trying to drill the strength out of the pipe wall."

Please elaborate the impotence of, 'one size down from the nominal size '. Does this mean, on 4" pipe the maximum tap can only be 3 ? Then how can he avail a 4" on a 4" line?

I suggested a way in my reply#26. You or other may have some better suggestion...

Maybe this link will help you both.

A fuller explanation of the system and physical aspects of 'pipe' - not 'tube'

Hi Guru, the question is not about the basics of Pipe or Tube. Let me make the question simple and straight forward:

Can a 4" hot tap be availed on a 4" pipe?

Yes, the Schedule 40 bore is bigger than 4"

But it's not "straight forward";

"Technically" - Hot tapping is performed on pipes from 1/2 " up to like 4 feet? bore. Vacuum to 4,000 psi?

The complication here seems to be "clean air" - so no lubricant, and/or not much effective coolant, for the cutter. Then there is the residual swarf problem, you'd need a large flow of air to purge (and have no certainty of achieving).

Personally; I'd go with Mobi - shut it down and fit a 'T' - having taken Trans's bypass advice.

So "Clean" is a major concern. "Cool" is a concern.

"Old" is another concern;

The pipe may be corroded, or include "old files" (hard spots) that eat a cutter - and then - to use the hot tapping technical term - "you're fuqked".

There may be 'no choice' for the OP - but I'd look very hard at everything else first.

"If the OP absolutely must have a full bore 4" off 4" branch then his only option is to de-pressurize, cut the line and weld a 4" tee into the line with a flange on the branch and may be a valve to run away from."

You well said this…

GA

Someone that has actually done it rather than just talking!

I have only been involved in hot taps a few times - new taps on natural gas lines passing our plant but what Gasman said is what we used for equipment and what we did.

Dependent on pressure I would suggest a flanged tee piece to take the 4" valve..............saves a lot of messing around........also may save a projection into the main pipe causing a problem with turbulent flow.

If you are connecting to a live (pressurized) water main, then you need to do the following to avoid contaminating the existing water main with bacteria, soil & mud, and metal shavings:

1). You need a Mechanical Joint 4 x 4 tapping tee with MJ Retainer Glands (w/ set screws), such as those made by the Mueller Co.;

2). A 4" Mechanical Joint Wet-Tapping Gate Valve, w/ MJ Retainer Glands (w/ set screws);

3). A Wet-tapping machine such as the type manufactured by The Mueller Co.;

4). A container of HTH so as to use in a water solution to disinfect (thoroughly) the tapping sleeve, tapping valve, and the tapping machine innards and the cutter;

5). 5/8" diameter steel retaining rods threaded at ends together w/ steel washers and hex head nuts;

6). Concrete for the thrust block to be constructed behind the tapping sleeve; size as directed by the Engineer of Record.

Never ever use the saw or dry tap the existing water main, because if do so you'll most likely contaminate the existing water main. I assume it is potable water main on a municipal distribution system. Make sure the chlorinated water solution has at least 250 mg/l (250 ppm) of free chlorine residual prior to disinfecting the aforementioned wet-tapping parts.

Have a great day!

Signed,

CaptMoosie, PE/PhD

Civil Engineer/Structural Engineer/Environmental Engineer

[also a former City Engineer]

The OP said air line.

"the pressurized line is critical of quality compressed dry air"