• No results found

PIPELINE SPAN NON-DESTRUCTIVE INSPECTION REPORT DYNEGY MOSS LANDING POWER PLANT JULY 19, REV A OWNER: CLIENT: PREPARED BY:

N/A
N/A
Protected

Academic year: 2021

Share "PIPELINE SPAN NON-DESTRUCTIVE INSPECTION REPORT DYNEGY MOSS LANDING POWER PLANT JULY 19, REV A OWNER: CLIENT: PREPARED BY:"

Copied!
82
0
0

Loading.... (view fulltext now)

Full text

(1)

PIPELINE SPAN NON-DESTRUCTIVE

INSPECTION REPORT

DYNEGY MOSS LANDING POWER PLANT

JULY 19, 2011 - REV A

MARK STEFFY - PRESIDENT LONGITUDE 123, INC. 2100 VALLEY MEADOW DRIVE OAK VIEW, CA. 93022 TEL. 805.649.9364 msteffy@longitude123.net

PREPARED BY:

TEL. 831.633.6687

thomas.w.brokaw@dynegy.com

BRIAN DUGAS, SENIOR PROJECT MANAGER/BIOLOGIST

PADRE ASSOCIATES, INC. 369 PACIFIC STREET SAN LUIS OBISPO, CA. 93401 TEL. 805.786.2650 x14 bdugas@padreinc.com

(2)

TABLE OF CONTENTS 1 – Inspection Overview 1.1 Purpose of Inspection ... 1 1.2 Conclusions ... 1 1.3 Facilities ... 1 1.4 Inspection Team ... 3

1.5 Inspection Equipment and Methodology ... 3

2 – Pipe Span Profile Drawing 2.1 Drawing Overview ... 7

Inspection Data Sheet – Inspection Location 0+00 ... 8

Inspection Data Sheet – Inspection Location 0+03 ... 10

Inspection Data Sheet – Inspection Location 0+18 ... 13

Inspection Data Sheet – Inspection Location 0+19 ... 15

Inspection Data Sheet – Inspection Location 0+39 ... 18

Inspection Data Sheet – Inspection Location 0+50 ... 21

Inspection Data Sheet – Inspection Location 0+59 ... 23

Inspection Data Sheet – Inspection Location 0+79 ... 26

Inspection Data Sheet – Inspection Location 0+99 ... 29

Inspection Data Sheet – Inspection Location 1+15 ... 32

Inspection Data Sheet – Inspection Location 1+19 ... 34

Inspection Data Sheet – Inspection Location 1+35 ... 37

Inspection Data Sheet – Inspection Location 1+36 ... 39

Inspection Data Sheet – Inspection Location 1+38 ... 41

Signature Page ... 43

Appendix A – Asbestos Analysis Report ... 44

Figures Figure 1 – Location Map ... 2

Figure 2 – Facilities Site Map ... 4

Figure 3 – Site Photos ... 5

(3)

 

1 - Inspection Overview 1.1 Purpose of Inspection

The purpose of this non-destructive inspection was to obtain measurements of the existing wall thickness of the steel pipe of the exposed and spanned segment of the Dynegy Moss Landing Power Generating Station marine terminal submarine fuel oil pipeline. These measurements are intended for use in a planned engineering study and evaluation of the structural integrity of this portion of the submarine fuel oil pipeline.

1.2 Conclusions

According to facility drawings provided by Dynegy, the submarine fuel oil pipeline at the location of the exposed and spanned segment of pipeline is comprised of 24-inch diameter, Schedule 20 steel pipe with an original wall thickness of 0.375 inches. Ultrasonic thickness measurements taken as part of this inspection of the pipe walls indicate that this section of pipeline currently has a minimum wall thickness of 0.360 inches.

Several areas of damaged weight coating and anti-corrosive coating were found within this exposed and spanned area and selected for inspection. These locations were at the 6:00 o’clock position at inspection locations 0+18, 0+50, 0+59 and 0+99. Wall thickness and visual inspection at these anomalous locations revealed base metal in fair condition with light to moderate to heavy scaling and pitting. Of note, the thickness gauging at inspection location 0+50 was relatively high at 0.395 inches. However, this measurement is probably in error due to the existence of heavy scale and corrosion products. The other anomalous locations were well cleaned and their wall thicknesses were measured between 0.360 and 0.365 inches.

With the exception of the 12:00 o’clock inspection locations at 0+50, 1+35, 1+36 and 1+38, the base metal at the remainder of the inspection locations were found in good condition with only light corrosion or pitting. The 12:00 o’clock inspection locations at 0+50, 1+35, 1+36 and 1+38 were found with higher levels of corrosion and pitting, but still in relatively good condition.

In general, the entire exposed and spanned segment of pipeline was found in good condition with no indications of severe anomalous conditions of any kind. However, anti-corrosive coating repairs are suggested at those locations where the anti-corrosive coating system has failed.

1.3 Facilities

The Dynegy Moss Landing Power Generating Station is located at Moss Landing, California, approximately 16 miles north of the City of Monterey, California. Pacific Coast Highway (PCH) divides the power generating facility from Moss Landing Harbor and the facility’s marine oil terminal (see Figure 1 – Location Map).

The marine oil terminal and its fuel oil pipeline component has been idle and in caretaker status since 1994. According to information provided by Dynegy, the offshore terminal was decommissioned in November 1994 and the cargo hoses and mooring system removed. However, it appears that the pipeline may not have been pigged or flushed but the offshore end of the pipeline contents (probably cutter stock) “displaced” with sea water to permit removal of the cargo hoses and placement of a 12-inch

(4)

SALINAS MONTEREY

(5)

 

blind flange on the offshore end of the pipeline. It is worth noting that, if this conclusion is accurate, the remaining portions of the pipeline may contain large quantities of cutter stock (light oil or diesel fuel).

The present marine terminal facilities consist of the submarine fuel oil pipeline comprised of 12-inch, 18-inch and 24-inch diameter pipe (see Figure 2 – Facilities Site Map).

The subject of this inspection report is an above-water section of the submarine pipeline exposed and spanned on an intertidal mudflat inside Moss Landing Harbor. This exposed span of 24-inch diameter, Schedule 20 steel pipe is approximately 140 feet in overall length measured from the earth embankment at the west end of the segment to its eastern termination out on the mudflat to the east of the embankment (see Figure 3 – Site Photos, Figure 4 – Site Photos and section 2 – Pipe Span Profile Drawing).

This exposed/spanned segment of pipeline is coated with a combination of weight coatings and anti-corrosive coatings of mixed and unknown composition. Approximately one-half of the spanned segment is coated with a cement-based weight coating and unknown anti-corrosive coating while the other half is coated with what appears to be a asphaltic/Somastic type weight coating/anti-corrosive coating along with various tar or fiberglass pipe wraps. All of the coatings were tested for the presence of asbestos and the “cement” type weight coating was found to contain 3% amosite asbestos (see Appendix A – Asbestos Analysis Report).

1.4 Inspection Team

The inspection was performed by a team of contractors and consultants. Dynegy contracted an asbestos abatement company to provide crews and equipment to remove the external pipe coatings at each inspection location approximately one week prior to the actual inspection. Dynegy consultant Padre Associates, Inc. provided a marine project consultant, Longitude 123, Inc. (L123), and Associated Pacific Constructors, Inc. (APC) to perform the actual inspection work. The inspection and recoating of the inspection locations was performed on June 13 and 14, 2011.

1.5 Inspection Equipment and Methodology

Initial surface preparation of the inspection locations was performed by the Dynegy asbestos abatement contractor. All weight coating, anti-corrosive coatings and corrosion products were removed by the asbestos abatement contractor at each pre-marked inspection location using handheld powered chipping hammers and wire wheels. All debris was contained and shipped offsite for proper disposal in accordance with the site’s asbestos abatement plan.

Final pre-inspection cleaning of each inspection location was performed by APC. Handheld grinders with wire-wheel brushes were used to polish each of the inspection locations. Inspection location 0+50, 6:00 o’clock position, had not been cleaned by the asbestos abatement contractor so surface preparation of this location was limited to wire-wheeling of the location and precluded removal of the existing coatings and products of corrosion. Ultrasonic measurements were performed through these coatings.

The thickness gauging were performed with a Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge with 2.25 MHz x 13mm dia. probe. Silicone was used as the coupling gel for these above water ultrasonic thickness gaugings.

The inspection locations were visually inspected and documented with color photographs at each location.

(6)

MARINE FUEL OIL PIPELINE BEACH VALVE BOX EXPOSED PIPELINE SEGMENT HARBOR JETTY

PACIFIC OCEAN

NORTH APPROXIMATE SUBMARINE PIPELINE ALIGNMENT

(7)

SITE PHOTOS FIGURE 3

Exposed and spanned marine fuel oil pipeline segment.

Spanned pipeline viewed from east side of intertidal mudflat. BLUFF

MUDFLAT

STATE PARK MUDFLAT

(8)

Looking at east termination in mudflat. Note asphaltic/Somastic type coating system.

(9)

 

2 - Pipe Span Profile Drawing

2.1 Drawing Overview

The following drawing titled Pipeline Exposure and Span Profile w/ Wall Thickness Gaugings provides detailed information about the profile of the subject exposure and span location on the Dynegy Moss Landing Power Generating Station marine oil terminal submarine fuel oil pipeline.

The profile measurements were taken using a taunt-line with level to provide a horizontal reference point. All vertical measurements are taken from the taunt-line to top-of-pipe or mudflat (sandline).

Horizontal distance measurements are measured from an informal benchmark established for this inspection at the top-of-pipe at the toe of the western embankment. This anchor point is represented as 0+00. The eastern end of the exposure is located at 1+40 at top-of-pipe.

Ultrasonic wall thickness gaugings were taken at approximate “clock positions” at 12:00, 3:00, 6:00 or 9:00 o’clock radial locations around the pipeline girth at specific horizontal distances from 0+00. The clock positions are based on facing west or toward the existing embankment/seaward with 12:00 o’clock on top, 3:00 o’clock to the right, 6:00 o’clock on the bottom, and 9:00 o’clock on the left.

The primary purpose of this drawing was to provide engineering parameters for use in creating a finite element engineering analysis of the pipeline exposure/spanned segment.

                         

(10)
(11)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+00

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, no corrosion or pitting found. 3:00 No measurement taken, below sandline.

6:00 No measurement taken, below sandline. 9:00 No measurement taken, below sandline.

(12)

PHOTO DOCUMENTATION:

0+00 – 12 o’clock position - Base metal in good condition, no corrosion or pitting found.

(13)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+03

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, no corrosion or pitting found. 3:00 Base metal in good condition, no corrosion or pitting found. 6:00 Base metal in good condition, no corrosion or pitting found. 9:00 Base metal in good condition, light corrosion but no pitting found.

(14)

PHOTO DOCUMENTATION:

(15)

 

(16)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+18

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 No measurement at this location, 12:00 measurement at 1+19. 3:00 No measurement at this location, 3:00 measurement at 1+19. 6:00 Heavy scale removed to expose light corrosion and pitting. 9:00 No measurement at this location, 9:00 measurement at 1+19.

(17)

 

PHOTO DOCUMENTATION:

(18)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+19

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, no corrosion or pitting. 3:00 Base metal in good condition, no corrosion or pitting.

6:00 No measurement at this location, 6:00 measurement at 1+18. 9:00 Base metal in good condition, no corrosion or pitting.

(19)

 

PHOTO DOCUMENTATION:

0+19 – 12 o’clock position – Base metal in good condition, no corrosion or pitting.

(20)

PHOTO DOCUMENTATION:

(21)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+39

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, no corrosion or pitting. 3:00 Base metal in good condition, no corrosion or pitting. 6:00 Base metal in good condition, no corrosion or pitting. 9:00 Base metal in good condition, no corrosion or pitting.

(22)

PHOTO DOCUMENTATION:

0+39 – 12 o’clock position – Base metal in good condition, no corrosion or pitting.

(23)

 

PHOTO DOCUMENTATION:

(24)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+50

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

3:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

6:00 Heavy scale was found over moderate pitting at this location.

9:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

(25)

 

PHOTO DOCUMENTATION:

0+50 – 6 o’clock position – Heavy scale was found over moderate pitting at this location. This inspection location was at an existing break in the pipeline weight coating and anti-corrosive coating.

(26)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+59

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, no corrosion or pitting was found at this location. 3:00 Base metal in good condition, no corrosion or pitting was found at this location.

6:00 Base metal in poor condition with heavy corrosion and pitting. This inspection location is at a pre-existing area of weight coat and anti-corrosion coating failure.

(27)

 

PHOTO DOCUMENTATION:

0+59 – 12 o’clock position – Base metal in good condition, no corrosion or pitting was found at this location.

0+59 – 3 o’clock position – Base metal in good condition, no corrosion or pitting was found at this location.

(28)

PHOTO DOCUMENTATION:

0+59 – 6 o’clock position – Base metal in poor condition with heavy corrosion and pitting. This inspection location is at a pre-existing area of weight coat and anti-corrosion coating failure.

0+59 – 9 o’clock position – Base metal in good condition, no corrosion or pitting was found at this location.

(29)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+79

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in fair condition, light corrosion and pitting was found at this location. 3:00 Base metal in fair condition, moderate corrosion and pitting was found at this location. 6:00 Base metal in fair condition, moderate corrosion and pitting was found at this location. 9:00 Base metal in fair condition, moderate corrosion and pitting was found at this location.

(30)

PHOTO DOCUMENTATION:

0+79 – 12 o’clock position – Base metal in fair condition, light corrosion and pitting was found at this location.

0+79 – 3 o’clock position – Base metal in fair condition, moderate corrosion and pitting was found at this location.

(31)

 

PHOTO DOCUMENTATION:

0+79 – 6 o’clock position – Base metal in fair condition, moderate corrosion and pitting was found at this location.

0+79 – 9 o’clock position – Base metal in fair condition, moderate corrosion and pitting was found at this location.

(32)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

0+99

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal found in good condition with isolated area of heavy corrosion and pitting. Thickness gauging taken on area of good metal.

3:00 Base metal in good condition. No corrosion and pitting found at this location. 6:00 Base metal in good condition with light corrosion and no pitting.

9:00 Base metal in good condition with light corrosion and no pitting. The longitudinal weld cap was found in good condition with no pitting.

(33)

 

PHOTO DOCUMENTATION:

0+99 – 12 o’clock position – Base metal found in good condition with isolated area of heavy corrosion and pitting.

(34)

PHOTO DOCUMENTATION:

0+99 – 6 o’clock position – Base metal in good condition with light corrosion and no pitting.

0+99 – 9 o’clock position – Base metal in good condition with light corrosion and no pitting. The longitudinal weld cap was found in good condition with no pitting.

(35)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

1+15

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

3:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

6:00 Base metal in good condition with no corrosion or pitting.

3:00 No measurement at this location, measurement at 6:00 only due to anomalous coating condition at the 6:00 position.

(36)

PHOTO DOCUMENTATION:

(37)

 

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

1+19

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition. No corrosion or pitting found at this location. 3:00 Base metal in good condition. No corrosion or pitting found at this location. 6:00 No measurement at this location, too close to sandline.

9:00 Base metal in good condition. No corrosion or pitting found at this location. Longitudinal weld cap found in good condition as well.

(38)

PHOTO DOCUMENTATION:

1+15 – 12 o’clock position – Base metal in good condition. No corrosion or pitting found at this location.

(39)

 

PHOTO DOCUMENTATION:

1+15 – 9 o’clock position – Base metal in good condition. No corrosion or pitting found at this location. Longitudinal weld cap found in good condition as well.

(40)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

1+35

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in fair condition, moderate pitting found at this location. 3:00 No measurement at this location, below sandline.

6:00 No measurement at this location, below sandline. 9:00 No measurement at this location, below sandline.

(41)

 

PHOTO DOCUMENTATION:

(42)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

1+36

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, light pitting found at this location. 3:00 No measurement at this location, below sandline.

6:00 No measurement at this location, below sandline. 9:00 No measurement at this location, below sandline.

(43)

 

PHOTO DOCUMENTATION:

(44)

 

INSPECTION DATA SHEET

INSPECTION LOCATION:

1+38

INSPECTION DATE:

6/13/11

INSPECTION NAME: Wall Thickness Gauging of Exposed Pipe Span

FACILITY LOCATION: Moss Landing Dynegy Generating Station, Moss Landing, California

TYPE OF INSPECTION: Ultrasonic Wall Thickness Gauging, Steel Pipe

INSPECTION EQUIPMENT:

Cygnus Multi Echo Ultrasonic Underwater Thickness Gauge w/ 2.25 MHz x 13mm dia. probe Ultrasonic

INSPECTOR:

Mark Steffy

UT CALIBRATION:

.500” Step Block - Steel

COUPLING GEL:

Silicone

INSPECTION DATA:

12:00 Base metal in good condition, light to moderate pitting found at this location. 3:00 No measurement at this location, below sandline.

6:00 No measurement at this location, below sandline. 9:00 No measurement at this location, below sandline.

(45)

 

PHOTO DOCUMENTATION:

(46)

The inspection findings documented in this report are true and correct having been planned, executed and observed by the following inspection manager:

_____________________________________ Mark I. Steffy

Inspection Manager

(47)

 

Appendix A – Asbestos Analysis Report

The following asbestos analysis report presents the results of tests performed on two samples of pipeline coating from the exposed, spanned pipeline section provided by Dynegy. The Fuel Oil Pipe Line Coating Location #2 was within the area of “cement” type weight coating while the Fuel Oil Pipe Line Coating Location #6 was within the area of asphaltic or “Somastic” type weight coating or pipe wrap.

(48)
(49)
(50)

July 19, 2011

Mr. Mark Steffy

Longitude 123

2100 Valley Meadow Dr.

Oak View, CA 93022

Dear Mr. Steffy:

Per your request, Thomas & Beers has performed hand calculations and finite

element analysis of a pipeline, owned and operated by Dynegy, and located

southeast of San Francisco near the city of Moss Landing, California. The

pipeline was originally installed as a buried line, though erosion and scouring

has caused a portion of the line to become exposed. The purpose of our

evaluation was to estimate stress and strain levels associated with this free

span.

The important geometric parameters and field conditions for the Dynegy

pipeline were provided to us, and are presented in Figure 1. As indicated in

this figure, the pipeline is nominal 24” Schedule 20 (24” OD with 0.375” wall)

with an assumed 1” concrete coat, and a free span of approximately 140’. For

the purposes of our evaluation, a wall thickness of 0.360” is assumed, based

on field measurements, as indicated in Figure 1. The material for the

pipeline is assumed to be mild steel similar to API-5L Grade B, with a

nominal minimum yield of 35,000 psi. Fundamental structural parameters

and simple structural evaluation calculations for the Dynegy pipeline are

presented in Table 1. Additional hand calculations are contained in

Attachment A.

The data provided in Figure 1 was used to build simple finite element models

for evaluating the pipeline. Graphical representations of the finite element

models are presented in Figure 2, where the locations of the analytical free

span is indicated. As shown in Figure 2, the finite element models assume a

somewhat simplified geometry, consisting of 50-foot segments that are buried

at the ends, with the free span running between them.

Soil spring rates are important analytical parameters that are needed to

accurately model pipelines. The analytical stiffness is a function of the soil

characteristics and individual pipeline properties. However, since the in-situ

(51)

generated at a different site that represent a relatively “stiff” model for fine

silty clay, typical for young bay mud. With un-drained shear strength of

30kPa for the soil, bi-linear soil spring definitions were calculated and used in

the finite element model. Since the soil properties were taken from a

different site, it is recognized that this estimate may be rough with respect to

the actual soil properties at the Dynegy pipeline. But by using a relatively

stiff model, the results should produce relatively high stresses at the margins

between buried and exposed pipe, which is a conservative approach if the

actual soil stiffness at the Dynegy site is less than our assumption.

Using the assumed soil properties, soil springs were included at each node of

the finite element model in the lateral, vertical, and axial directions where

the pipeline model is buried at the ends — in the free span none were

activated. To adequately characterize the possible analytical configurations,

two models were necessary — one assuming the pipeline is drained, and one

that assumes it is flooded with seawater, and these models were also

evaluated using both elastic and plastic material models. Elastic material

models assume that steel stress levels can increase linearly beyond the

specified yield point, and in the plastic models, stresses above the specified

minimum yield cause permanent deformation (plastic strain) as the material

yields.

Seismic loading was also considered in the analytical model of the Dynegy

Moss Landing pipeline, per your request. The seismic load calculations

consist of static equivalent loads that are based on a percentage of the overall

mass of the pipeline. This technique, known as the “equivalent lateral force

procedure,” was taken from

Minimum Design Loads for Buildings and Other

Structures

, ASCE/SEI 7-05, and is compatible with the 2010 California

Building Code. Attachment A contains a detailed account of how each of the

design loads was derived. Seismic parameters were calculated using

site-specific earthquake variables and a modal analysis of the structure. Using

this information, a C

s

of 0.28 was calculated, with E

h

= .28G and E

v

= .19G.

These earthquake factors were combined with the gravity loads to

approximate the maximum seismic load case conditions as recommended in

the ASCE document.

Table 2 is a summary of the important results from the finite element

analysis of the Dynegy pipeline. As indicated, the maximum elastic

(52)

bending stress is 48.4 ksi for this load case, which is above the nominal yield

stress of 35 ksi, confirming the need to perform plastic analysis. When the

model is analyzed with plasticity, the maximum stress drops (as expected) to

35.5 ksi, while the maximum displacement increases to just over 3 feet (38.8

inches) and is associated with a maximum plastic strain of 0.44 percent. As

can be seen in the top portion of Table 3, the gravity load case results are

similar to the seismic results, except the magnitudes are smaller.

Figures 3 – 21 present the analytical results in graphical form. For example,

Figure 3 is a side view of the displaced shape (greatly exaggerated), and

Figure 4 shows the same displacement from an isometric perspective for the

elastic models under gravity loading. Figure 5 is an equivalent (von Mises)

stress contour plot, where the location of the maximum stress is indicated

with an “MX” and Figure 6 is an isometric view of the same data. As can be

seen, the maximum stress is located directly adjacent to the beginning of the

free span where the pipeline extends from the buried portion of the line. This

was found to be the case for all the load cases and models, and Figures 6 – 14

are similar plots for these other scenarios. The load case and maximum

results associated with each figure can be determined by reviewing the titles

and the legend at the upper left-hand corner of each figure. Figures 15 – 21

present more meaningful results for the nonlinear plastic analysis. Figures

15 – 17 show the extent of the pipeline material that is above yield for the

seismic load case and flooded model at both ends of the free span, where all

stresses above 35 ksi are depicted in gray. Figures 18 – 21 show the

nonlinear plastic strain in the pipelines.

It should be noted that the finite element analysis assumes that the model

geometry is input in the “as-measured” field position as a stress-free state,

and then displaces from that position based on the input loads. Strictly

speaking, this is not an accurate simulation since the existing field position

actually represents a gravity-loaded displaced shape. However, since the free

span is relatively long and quite flexible, the results should be valid within

the analytical accuracy of the model.

Based on the results of our analytical evaluation, it is highly likely that the

Dynegy Moss landing pipeline have already been subjected to levels of stress

that are above yield due to the length of the free span, and have therefore

experienced a certain level of plastic strain. This field condition was probably

not anticipated in the original design premise of the pipelines, and as such,

(53)

However, the calculated levels of strain associated with the current field

conditions are quite small, and are far less than those that would be likely to

cause catastrophic failure, even during a seismic event. The maximum

analytical equivalent strain is approximately 0.44% for the flooded condition,

and a suggested allowable strain for bending due to unplanned in-situ

buoyancy (a similar condition) is 0.5%

1

. However, this recommended

allowable strain is premised upon repairing the field condition as soon as it is

identified. It should be noted that our evaluation is based on actual field

measured wall thickness, thus providing additional confidence in the

adequacy of the current field conditions. Nevertheless, additional erosion and

scouring that increases the measured free span could increase the stress and

strain in the pipeline dramatically. If possible, we recommend repairing the

existing field conditions as soon as possible to reduce the length of the free

span section of the pipeline to an acceptable level.

Please let us know if you require additional information, or if we can answer

any questions you may have.

Very truly yours,

David L. Thomas, P.E.

Partner

Enclosure

1

American Lifelines Alliance, July 2001;

Guideline for the Design of Buried

Steel Pipe.

(54)
(55)

Outside Pipe Diameter: 24.000 inches ODP Pipe Wall Thickness: 0.360 inches tp Inside Pipe Diameter: 23.280 inches ID Pipe Density: 490.000 pcf PD Pipe Yield Stress: 35.000 ksi Fy Pipe Modulus of Elasticity: 29000.000 ksi E

External Coating: None - -External Coating Thickness: 0.000 inches te External Coating Density: 0.000 pcf ED Total Outside Diameter: 24 inches ODE

Concrete Coating: Yes - -Concrete Coating Thickness: 1.000 inches tc Concrete Coating Density: 140.000 pcf CD Concrete Outside Diameter: 26.000 inches ODC

PIPE WEIGHTS:

Pipe Weight in Air: 90.98 lb/ft Wap Coating Weight in Air: 0.00 lb/ft Wac Concrete Weight in Air: 76.36 lb/ft Wae Total Flooded Weight in Air: 356.51 lb/ft Wa1 Total Dry Weight in Air: 167.34 lb/ft Wa2 Total Sealed Weight in Seawater: -68.63 lb/ft Wsw Total Flooded Weight in Seawater: 120.55 lb/ft Wfw

FREE SPAN DATA:

Section Modulus: 155.68 in^3 S Allowable Bending Stress (.8Fy includes 1/3 increase): 28.00 ksi Fb

Max Unsupported Span in Air: 131.78 feet La Max. Unsupported Span in Air(flooded w/ seawater): 90.28 feet Lfw

MINIMUM BEND RADIUS DATA:

Allowable Bending Stress (.8Fy): 28.00 ksi Fb Maximum Strain (Fb/E): 9.66E-04 in/in Strain

Angle Alpha: 4.02E-05 degrees alpha Minimum Bend Radius: 1035.714 feet R

(56)

X

Y

Z

Fixed boundary condition

Free Span = 140' geometry

built from field measurements

Buried section = 50'

with soil springs

Fixed boundary condition

Flooded Model

Drained Model

Note: Models are identical except for flooded vs. drained

Buried section = 50'

with soil springs

(57)

Elastic Material, Flooded 25.13 42,472 N/A Plastic Material, Drained 9.53 19,241 0.00% Plastic Material, Flooded 25.63 35,054 0.04%

Maximum Displacement Maximum Equivalent Stress Maximum Plastic Strain

Seismic Loading (inches) (psi) (percent)

Elastic Material, Drained 11.30 22,122 N/A Elastic Material, Flooded 30.83 48,389 N/A Plastic Material, Drained 11.30 22,122 0.00% Plastic Material, Flooded 38.79 35,552 0.44%

(58)

X

Y

Z

TIME=1

DMX =25.126

(59)

X

Y

Z

TIME=1

DMX =25.126

(60)

MN MX

X

Y

Z

TIME=1 SEQV (AVG) DMX =25.126 SMN =.443E-08 SMX =42472

(61)

MN MX

X

Y

Z

.443E-08

9438

18877

28315

37753

TIME=1 SEQV (AVG) DMX =25.126 SMN =.443E-08 SMX =42472

(62)

X

Y

Z

TIME=2

DMX =30.833

(63)

X

Y

Z

TIME=2

DMX =30.833

(64)

MN MX

X

Y

Z

TIME=2 SEQV (AVG) DMX =30.833 SMN =3.83 SMX =48389

(65)

X

Y

Z

TIME=1

DMX =25.613

(66)

X

Y

Z

TIME=1

DMX =25.613

(67)

MN MX

X

Y

Z

.462E-11

7790

15579

23369

31159

TIME=1 SEQV (AVG) DMX =25.613 SMN =.462E-11 SMX =35054

(68)

X

Y

Z

TIME=2

DMX =38.79

(69)

MN MX

X

Y

Z

1.433

7902

15802

23702

31602

TIME=2 SEQV (AVG) DMX =38.79 SMN =1.433 SMX =35552

(70)

MX TIME=2 SEQV (AVG) DMX =38.79 SMN =1.433 SMX =35552

Yielded area in gray

(71)

MX

0

7778

15556

23333

31111

TIME=2 SEQV (AVG) DMX =38.79 SMN =1.433 SMX =35552

Max Stress = 35.55 ksi

(72)

TIME=2

SEQV (AVG) DMX =38.79 SMN =1.433 SMX =35552

Yielded area in gray at

right-hand support

(73)

MN MX

X

Y

Z

0

.978E-03

.001955

.002933

.00391

TIME=2 NLEPEQ (AVG) RSYS=0 DMX =38.79 SMX =.004399

(74)

MX TIME=2 NLEPEQ (AVG) RSYS=0 DMX =38.79 SMX =.004399

Maximum plastic strain = .44%

(75)

MX

0

.978E-03

.001955

.002933

.00391

TIME=2 NLEPEQ (AVG) RSYS=0 DMX =38.79 SMX =.004399

Maximum plastic strain = .44%

viewed from below

(76)

TIME=2

NLEPEQ (AVG) RSYS=0

DMX =38.79 SMX =.004399

(77)

Attachment A

(78)
(79)
(80)
(81)
(82)

References

Related documents

15 Years Terry Albin, CFP® Ameriprise Financial Thomas Archer, CLU, ChFC Elite Marketing Group Heidi Davis, CFP® Linscomb & Williams Norman Davis, CFP®, CPA Linscomb &

Process CyanProcess Magenta Process MagentaProcess Yellow Process YellowProcess Black Process BlackPANTONE 287 M PANTONE 287 M... In these hectic times, complete rest is at

In a typical controlled laboratory experiment where subjects make choices in the same environment repeatedly, clustering at a participant level is inherited from the

E se a historia da literatura galega é unha historia de descuber- tas, empezando pola primeira e máis principal, a da propia lingua, Uxío Novoneyra deixounos de entre

Focusing discussion on evaluating impacts of formal change programmes, often driven by official ‘change makers’ (programme directors, specialist consultants, museum managers),

This data element may contain the same information as ''Provider location address postal code''.. Provider Business Mailing Address

Data reported in Table 5 on intra-regional shares of trade in total manufacturing, components and final goods for various regional economic groupings help understand this

This system will be used in the article in order to develop a complaint process model using indicators signalling the level of claims realized in bank X that in the aspect of