abbver98 2

[2ndchild]

hi,

thank you for your answer but I would know more details:
is the formula e = Pc*(D0/2)*f*z
or e = (Pc*D0)/2*f*z
I think it's the first one. isn't it?
please, can you explain me the meaning of each parameter? f and z?
thank you very much

regards,

 

[abbver98]

I just read your post today.
Z : is like E welding factor
f : is the allowable stress in EN standard (13445 and 13480) it's calculated, so you had to have yield strength (at temperature and room) and tensile strength.
I'll come back with values

 

[abbver98]

Formula below is for straight pipe

steel other than austenitic steel :
f=max(ReH/1.5 or Rp0.2/1.5; Rm/2.4)
austenitic steel :
f=max(Rp0.1/1.5; min(Rmt/3 ; Rp1.0t/1.2))
steel castings:
f=max(ReH/1.9 or Rp0.2/1.9; Rm/3.0)

in the other hand : (some considerations are underlined in the standards)
-100% NDT : z=1
-Random NDT : z=0.85
-0% NDT : 0.7

 

[2ndchild]

thanks abbver98,
I have some data "f" for stainless steel at room, high and low tempreture.
but, do you know how we can evaluate the max allow pressure whitout using the the thickness formula or process engeneer?
regards,

 

[2ndchild]

abbver98,
when you have 100%ET + no random test or no random + single butt, z takes the value of 1.0?
thanks

 

[abbver98]

no random + full penetration : z=0.7, I had to see EN13480 Part 4 for acceptable weld joint.
What is ET ?

 

[abbver98]

You can't evaluate the MAWP without using formulas. You can find some Pipe manufacturer brochure with thickness and MAWP but they use the same approach.

 

[2ndchild]

hi,
ET means Eddy-current testing
In that case,I think z=0.85 because of the current testing!
isn't it?

 

[FIF99]

Hi,

in case of 100% NDT, e.g. EddyCurrent or X-ray, than z=1.

Regards.

 

[2ndchild]

OK, you're always right!
best regards.

 

[2ndchild]

In case of 100% Eddy-current testing and no RT (radiographic testing)than z=0.85
because, 100%ET is not considered as 100%NDT

http://www.outokumpu.com/pages/Page____11024.aspx

????
Leyla

 

[FIF99]

Hi 2ndchild,

May be your're right, but be aware that these requirements differs depending on the applicable design code.
ASME B31.3 may stipulate that z=0.85 in case of ET, but do the EN standards use the same safety factors?
From the Outokumpu site you are refering to it seams that the EN standard do accept a factor of 1.0 in case of ET.
ASME B31.3 only allows for 1.0 if 100% RT, but it is not clear (sofar) if they accept ET as an alternative for RT.

Regards.