b31gpf {pipenostics}

ASME B31G. Failure pressure of the corroded pipe (original)

Description

Calculate failure pressure of the corroded pipe according to Original B31G, Level-1 algorithm listed in ASME B31G-2012.

The next assumption of the corrosion shape is adopted by ASME B31G-2012:

There (a) is a parabolic and (b) is a rectangular idealizations of a corroded area.

Usage

b31gpf(d, wth, smys, depth, l)

Arguments

d

nominal outside diameter of pipe, [inch]. Type: assert_double.

wth

nominal wall thickness of pipe, [inch]. Type: assert_double.

smys

specified minimum yield of stress (SMYS) as a characteristics of steel strength, [PSI]. Type: assert_double.

depth

measured maximum depth of the corroded area, [inch]. Type: assert_double.

l

measured maximum longitudinal length of corroded area, [inch]. Type: assert_double.

Details

Since the definition of flow stress, Sflow, in ASME B31G-2012 is recommended with Level 1 as follows:

Sflow = 1.1SMYS

no other possibilities of its evaluation are incorporated.

For this code we avoid possible semantic optimization to preserve readability and correlation with original text description in ASME B31G-2012. At the same time source code for estimated failure pressure preserves maximum affinity with its semantic description in ASME B31G-2012 and slightly differs from that given by Timashev et al. The latter deviates up to 0.7 (b31gdata).

Numeric NAs may appear in case prescribed conditions of use are offended.

Value

Estimated failure pressure of the corroded pipe, [PSI]. Type: assert_double.

References

1. ASME B31G-2012. Manual for determining the remaining strength of corroded pipelines: supplement to B31 Code for pressure piping.

2. S. Timashev and A. Bushinskaya, Diagnostics and Reliability of Pipeline Systems, Topics in Safety, Risk, Reliability and Quality 30, DOI 10.1007/978-3-319-25307-7

See Also

Other fail pressure functions: b31gmodpf, dnvpf, shell92pf, pcorrcpf

Other ASME B31G functions: b31crvl(), b31gacd(), b31gacl(), b31gafr(), b31gdep(), b31gmodpf(), b31gops(), b31gsap()

Examples

 library(pipenostics)

 ## Example: maximum percentage disparity of original B31G
 ## algorithm and modified B31G showed on CRVL.BAS data
 with(b31gdata, {
   original  <- b31gpf(d, wth, smys, depth, l)
   modified  <- b31gmodpf(d, wth, smys, depth, l)
   round(max(100*abs(1 - original/modified), na.rm = TRUE), 4)
 })
 ## Output:
 #[1] 32.6666

 ## Example: plot disparity of original B31G algorithm and
 ## modified B31G showed on CRVL data
 with(b31gdata[-(6:7),], {
   b31g  <- b31gpf(depth, wth, smys, depth, l)
   b31gmod  <- b31gmodpf(depth, wth, smys, depth, l)
   axe_range <- range(c(b31g, b31gmod))
   plot(b31g, b31g, type = 'b', pch = 16,
        xlab = 'Pressure, [PSI]',
        ylab = 'Pressure, [PSI]',
        main = 'Failure pressure method comparison',
        xlim = axe_range, ylim = axe_range)
   inc <- order(b31g)
   lines(b31g[inc], b31gmod[inc], type = 'b', col = 'red')
   legend('topleft',
          legend = c('B31G Original',
                     'B31G Modified'),
          col = c('black', 'red'),
          lty = 'solid')
 })