One last question: How on Earth (or should that be "under water"?) does one use the attenuation formulae in ISO 15589-2? Plot potentials against distance and see where they cross the magic line or is there a better way?
Right, calculations checked, answers are:
RP-F103:
For 3-layer polypropylene anti-corrison coating (CDS 3) and 300 mm long IMPU field joint coatings (3D system) 25 year design life I get:
fcm = 1.375E-3 for the line pipe
fcm = 0.01375 for the FJC
For a 25 mA/m2 maintenance current density...
Guys
Working on a project which involves SUBSEA structures with duplex stainless steel (probably API 5LC LC65-2205) cooling loops within them. Inlet temperature is about 100 Celsius, although some "headroom" might be advisable.
Need to spec. amn anti-corrosion coating for the loops (which...
Guys
Working on a project which involves SUBSEA structures with duplex stainless steel (probably API 5LC LC65-2205) cooling loops within them.
Inlet temperature is about 100 Celsius, although some "headroom" might be advisable. Need to spec. amn anti-corrosion coating for the loops (which...
Can't use a conventional buckle detector with reeled pipe - the pipe is one continuous length and so unless you want to insert ?km of cable inside the reeled pipr it won't work. Flipside is reeled pipe will have a low D/t ratio (typical rule of thumb D/t < 20) and is thus lees prone to buckling...
Beware of using re-moulded values.
These assume the clay returns to a nice goo-ey mass soon after backfilling. For a soft clay (basically fish poo and other marine detritus) this may be somewhat true, but for stiffer clays the backfill may resemble more of a ploughed field with the backfill...
As for perception, yes, I agree we are all driven by that. On the other hand, very few pipelines have failed due to over-protection and anodes cost buttons compared to the rest of the flowline and its installation.
DNV would have you believe a couple of old aluminium takeaway food trays...
Working on a pipeline coated with 2.5 mm 3-layer polypropylene (nothing outstanding about it).
Using RP-F103 Table A.1 and a 3-layer FBE/PP coating I get:
a=0.1x10E-2
b=0.003*10E-2
giving
fcm = a +0.5*b*T = 0.1x10E-2 + (0.5*0.003x10E-2*25)
fcm = 0.001375
and
fcf = a + b*T
fcf = 0.1x10E-2 +...
