Converting pipe schedule to wall thickness in inches - up to 24 inches The usual stipulation applies - this is just a page on the internet. Double check your work. We present here three tables, 1/8 inch to 3 1/2, 4 to 8, and 10 to 24 inch. There's a few gaps here and there, but the info's mostly all here.
My brother, Kenneth was the master of the 8 minute flange-up. He documented how many of these he made, but I don't know the number. He once told me the secret (besides having your own impact that you KNEW would work) was in the preparation. Keep in mind that he worked almost exclusively in Bay Marchand - 60' and less.
Several steps are necessary.
In the procedure below, OD, WT, ID, RADIUS, and IDR2 are all in inches. LENGTH is in feet. FVFP, and FVP are in cubic feet.
1. Measure outside diameter (OD) and wall thickness (WT).
2. Multiply WT x 2 and subtract it from OD to get inside diameter (ID).
3. Divide ID by 2 to get the radius of the internal diameter (RADIUS).
4. Multiply RADIUS x RADIUS to get the square of the ID radius (IDR2).
5. Add together the length of the pipeline + any risers + any spool pieces to get the total
length (LENGTH).
6. Multiply IDR2 x 3.14 and divide the answer by 144 to get the floodable volume per foot
of pipe (FVFP).
7. Multiply FVFP x LENGTH to get floodable volume in cubic feet of the entire pipeline
(FVP). This is your answer.
8. If you need your answer in gallons instead of cubic feet, multiply FVFP x 7.48
This is the math for calculating spool piece size and angle if you don’t have software for it. Spool piece to be fabricated shown in blue. Hard line measurement flange to flange, from top dead center of leading edges, shown in brown. Angles A & B are read as offsets from 90 degrees if using jigs or are the measured angles between straight-line rope and line AB if using rope and hand probes.
Single Bend 1. Obtain angles A & B 2. Measure length AB 3. Calculate Angle C
C = 180 - (A + B) 4. Convert A, B, & C to Radians Ar = 3.14 / (180 x A) Br = 3.14 / (180 x B) Cr = 3.14 / (180 x C) 5. Calculate leg lengths AC = AB x SIN Br / SIN Cr BC = AB x SIN Ar / SIN Cr
Answers: AC & BC are the distances from the existing flange faces to the working point (C). Angle C is the angle the elbow will have to make. Fabricators will have to subtract flange width and elbow radius from each leg length.
An in-water tip for getting your o-ring back into the skillet when it pops out: Courtesy of M Roehl "For a quick way to install an o-ring in a skillet just place the o-ring in the grove of the flange and place the skillet over the top, tap it with the heel of your hand (small skillet's up to say 10"/12") it will seat right around the o-ring and because it can't go past the flange face it goes right on and won't slip off. This works well in the water and out. For bigger o-rings you will need a small mall. Try it, it works every time."
A common mistake is to run the eyes of the lacing sling back through the corresponding holes on the other flange before connecting them to your lift bag or tugger. Better if you run them into bolt holes that are lower. For example, go from 10 and 2 on the first flange to 9 and 3 on the second, and then to your lift bag. This keeps the second flange from sagging and makes it a lot easier to stab your drift pins.
Never...never....never....leave the surface without 1) a large hammer, 2) two drift pins the right size 3) your chamber bag loaded with a can of Skoal so you can enjoy a big fat dip and a cup of coffee whilst reflecting on how you'll handle HERO STATUS on account of your flange success because you remembered to take along items 1) and 2), once your chamber run is over.....Reefer
After you have a couple of bolts in your flange and you want to check the gap - in zero viz of course - hold a nut between your thumb and forefinger where they come together. Now you can still use your finger tip to feel the gap, but if the flanges come together on you they will pinch the sides of the nut and not your fingers. Of course you never want to put fingers between flange faces anyway and everybody knows none of us ever do...
To adjust the fit of a micarta (non-conductive) flange skillet: Tighter - Remove the plastic insert from the skillet. Wrap teflon tape around the diameter of the insert inside the groove. Put the insert back in the skillet. The more tape, the tighter the fit. Looser - Use your Big Chief to scrape evenly all the way around the insert until the O ring goes in.
To adjust the fit of a metal flange skillet: Tighter - Take a center punch and hammer all the way around the inside diameter of the skillet at 1" intervals about 1/8th of an inch from the inside edge. Secure with teflon tape if necessary. Looser - File lightly around the inner diameter of the skillet.
A word on the bigger sizes of O rings & metal skillets:
The larger O rings as supplied are very often a little out of round and difficult to get into a skillet. When this is the case, you may find it helpful to lay the O ring on a flat surface and lay some thin spacers alongside it. These spacers should be a little less than half the width of the O ring. Next, lay the skillet over the O ring and you can force it on without it popping all the way over the O ring and off the other side.
This is actually a flange breaking tip. With all the decommissioning going on world-wide there is a good chance that you will find yourself with a couple of flogging spanners and a man-sized hammer removing a spoolpiece from a riser.
The bitch about undoing a flange is that the flange faces bear on the nuts as you loosen them, causing friction all the way back to the point where the flange is no longer under tension. This means that you are hammering every bolt all the way back, and you are going to get fatigued. You will start to get pissed off with the flange, and you will swear at it between gasps of gas. Your arms will start to feel like rubber, and that hammer that made you look so cool and tough on deck will start to weigh a ton as you feebly tap the fifteenth bolt around.
To avoid all this drama, and make yourself look pretty good in the process, use the magic flangebolt trick. What you do is first loosen and remove only the 12 o-clock bolt. You then fit that bolt above its' hole with the nuts tight up against the outside edges of the flange. Once you start to loosen the other bolts, the tension is taken up by the "magic" bolt, allowing you to free the other bolts quite easily, without the dreaded friction. Start at the bottom and work your way up, just in case the magic bolt should happen to spring off prematurely.
Once you have loosened and removed all the bolts (and stored them neatly in a workbasket of course) you are left with a flange held together with one bolt at the top. Get off to one side, and at the full reach of your sledgehammer tap the bolt upwards. Make sure your hat camera is focused on the proceedings so that all the topside pukes can gaze in wonderment as the flange springs magically apart.
If the guy before you cleaned the marine growth off the bolts properly you should barely be breathing hard at this point. You will have to wait a bit until the blind flange for the riser is rigged, because the deck crew didn't expect you to be finished so quickly. Use this time wisely by hunting for lobsters.
If someone else should happen to be going in to break a flange before you, tell him the trick, otherwise you will arrive to find a half open flange waiting to be sweated over. You will lose some glory this way, but at least you won't have to lose your cool.
Here's a salute to Joe Vidrine who single handedly saved thousands of fingers of the men doing the tie ins. Not to mention the thousands of dollars he has saved the oil companies. Christ, the Oil Companies should give you a bonus!!!
Are there any company men out there that can remember trying to set the O ring with welding rods and Teflon tape? Can you remember trying to find the leaks in the flange from a pinched welding rod in the flange?
Can any divers remember a 6-8 ft sea tie in, trying just to pin the moving mass of metal only, to sweat it out the whole dive trying to get the ring in with out a resulting leak.
Here's to you Joe; you have a good logical brain. Like my father always said, "Use your head or your ass pays the bill." Replace ass with fingers and there you have it.
Flanges & Tie-ins
Never...never....never....leave the surface without 1) a large hammer, 2) two drift pins the right size 3) your chamber bag loaded with a can of Skoal so you can enjoy a big fat dip and a cup of coffee whilst reflecting on how you'll handle HERO STATUS on account of your flange success because you remembered to take along items 1) and 2), once your chamber run is over.....Reefer