IPC2000-238 - ASME Digital Collection

TECHNICAL AND ENGINEERING CHALLENGES FACED IN DESIGN OF THE GELUGOR MAINLINE, PENANG, MALAYSIA

Ir. Hj. Ahmad Khairiri, Abdul Ghani, P. Eng. Site Construction Manager, Penang Lateral Projects

Technical and Facilities Development Division PETRONAS GAS BERHAD

ABSTRACT PETRONAS Gas Berhad (PGB), a listed partly-owned

subsidiary of PETRONAS is undertaking the Peninsular Gas Utilization Project - Stage III (PGU III). The PGU III Sector 2 & 3 project extends from Lumut, Perak to Pauh, Perlis on the West Coast of Peninsular Malaysia, with two laterals, the Gurun Lateral and the Penang Lateral. The Penang Lateral is further divided into the Prai Lateral, Gelugor Mainline and the Gelugor Tenaga National Berhad (TNB) Meter Station project individually.

This paper will focus its' discussion on the technical and engineering challenges faced in the design of the Gelugor Mainline Project. The Gelugor Mainline consist of about 7 km NPS 24 gas pipeline which runs from TNB Prai Power Plant of the mainline to TNB Gelugor Power Plant on the Penang Island. The pipeline is planned to operate at high pressure. The pipeline route traverses complex terrain with varied seabed lithology with depth up to 16m. The pipeline will cross active shipping lane, zones of live electrical cables, extensive system of submarine pipeline, mudbank and areas susceptible to mass gravity flows. There is also an area subjected to future development with an expected 170 kN/m2 distributed load with 3 m covers required which is an expressway and Light Rapid Transportation (LRT) system, the proposed development of a "Vision City" is also a few meters away from the pipeline. The pipeline also passes by an environmentally sensitive area that includes the rearing of caged fishing activities.

It is essential for the project team to determine and investigate the variable risks to the pipeline in order to take appropriate evasive and mitigating action in design. This required comprehensive survey activities in the busy shipping straits. The paper will explore and detail out its' study starting from the description of the design concept to the varied

environmental challenges. This paper aims to describe the route selection process, the pipeline design process and outline some of the specialist techniques employed in the design construction of the Gelugor Mainline, Penang, Malaysia. In nearly every major project a drive for cost and risk reduction results in a number of new ideas with varying degree of impact. Hence, the following areas will be elaborated and presented in greater details:

• Pipeline Design. • Pipe-lay vessel. • Pipeline installation methodology.

INTRODUCTION PETRONAS Gas Berhad (PGB), a listed partly-owned

subsidiary of PETRONAS is undertaking the Peninsular Gas Utilization Project - Stage III (PGU III). The PGU III Sector 2 & 3 project extends from Lumut, Perak to Pauh, Perlis on the West Coast of Peninsular Malaysia, with two laterals, the Gurun Lateral and Penang Lateral. The Penang Lateral is further divided into the Prai Lateral, Gelugor Mainline and the Gelugor Tenaga National Berhad (TNB) Meter Station project individually. The Prai Lateral consist of 21.7 km of NPS 24 gas pipeline which runs from Lunas, Kedah to the TNB Prai Power Plant in Prai, Pulau Pinang. Commercial gas delivery metered at Gelugor TNB Meter Station is scheduled to start in mid 2000.

The Gelugor Mainline consist of a 7 km NPS 24 gas pipeline which runs from TNB Prai Power Plant in Prai, Pulau Pinang of the mainline to TNB Gelugor Plant on the Penang Island. The pipeline passes across the Straits of Penang about parallel with the Penang Bridge, the longest bridge in South East Asia. The pipeline is planned to operate at high pressure sales gas with a design pressure of 70 bar (6895 kPa). The

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pipeline route traverses complex terrain with varied seabed lithology with depth up to 16m. The pipeline will cross active shipping lane, zone of live electrical cable, an extensive system of submarine pipeline and areas susceptible to mass gravity flows to name a few. Location Plan is shown in Figure 1.

Since the risk is very high it is essential far the project team to determine and investigate the variable risks in the pipeline project up front. Appropriate evasive and mitigative action was taken in the early design stage. This requires comprehensive survey activities in largely variable terrain. The main activities for the Gelugor Mainline Project can be summarized in Figure 2: Main Activities For Gelugor Mainline Project. It kicks off with an initial route selection study, inclusive of various activities and complete with the introduction of sales gas thru commissioning in the system.

Engineering, procurement, construction, commissioning (EPCC) contract for the project was awarded to Pi Gas Billfinger Berger Civil Construction Joint Venture which later subcontract the Engineering work to Mentor Engineering and the post trenching activity to Sumai Engineering to name a few. The owner of the system is PETRONAS Gas Bhd. The summary of the project data is included in Table 1 : Gelugor Mainline Project Data.

ROUTE SELECTION Initially the route was to pass by the southern tip of

Penang Island to cater for a new Independent Power Producer there but somehow this plant was not materialized. Then TNB power plants both at Gelugor and Prai requires gas for their power generation. It was finally decided that the pipeline route should passes both power plants. The route selection process identified and adapted here where merely cost driven due to scarcity of land especially on the shore approach part. Some of the basic criteria in selecting the route chosen include the followings:

• Shortest possible route • Avoiding hazardous area • Avoiding existing anchoring zone with the planning to

include a portion of the selected route as part of the non anchoring zone.

• Avoiding other pipeline or cable crossings as much as possible.

• Avoid area of intensive caged fishing activities. • Avoid bottom obstruction or depressions that may create

the massive pipe span.

The route selected for the project passes through a few obstacles namely the followings:

• Extensive system of submarine pipeline - At the Prai site there is 4 number of NPS 10 oil pipeline and one cable running to a nearby jetty where the proposed pipeline had to cross.

• Port activities - This include a busy port and active shipping lane where ships make a turning point here. The design of the pipeline has to cater for anchor drop and drag, which might happen here in the future. During construction, there is also stopping of work activity every time a vessel passes by.

• Prai River mouth or delta - Design to include high under current reaching up to 4 knots and the mass gravity flow on the seabed which shall be elaborated further below. The sea floor of the Prai River mouth is prone to siltation (sedementation built-up), which needs further design condition in trench work during construction.

• Non anchorage zone - This make anchoring difficult, sometimes anchoring system had to extend anchor from 300 to 400 m's.

• Life electrical cables - There are 5 life electrical cables (125 kV and 33 kV) in the Non Anchorage Zone, which supplies electricity to Georgetown on the Penang Island. Any disruption to this life cable might have a political and adverse impact to the surrounding area. A close monitoring was implemented during the construction stage.

Pipeline Location Gelugor Mainline Location Seberang Prai, Mainland

Peninsular Malaysia to Penang Island

Product Natural Gas Pipeline Outside Diameter (mm) 609.6 ( 24 inch ND) Pipeline Wall Thickness (mm) 15.9 Pipeline Material Type/Grade Spiral Welded Carbon

Steel API 5LX 60 Pipeline Design Temperature (degC)

55

Pipeline Length (m) 6466 Pipeline Design Life (years) 25 Maximum Water Depth (m) 16 Pipeline External Corrosion Coating

3 Layer Polyethylene

Pipeline Corrosion Coating Thickness (mm)

3.0 (minimum)

Pipeline Internal Coating Liquid Epoxy Pipeline Internal Coating Thickness (mm)

0.35

Required Concrete Weight Coating Thickness (mm)

40.0

Required Concrete Coating Density (in air, kg/m3)

3044

Hydrotest Pressure (Mpa) 9.66 Table 1: Gelugor Mainline Project Data

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• Middle Bank - This is a mudbank area where working here is very tide dependent. Here, the proposed development of a "Vision City" is in planning stage. The planning of this proposed city shall also taken into consideration the minimum distance required from the pipeline

• Expressway - There is also an area subjected to future development with an expected 170 kN/m2 distributed load with 3 m covers required which is an expressway and Light Rapid Transportation (LRT) system. However, both this projects need some reclamation to be conducted first.

• The pipeline also passes by an environmentally sensitive area, which include the rearing of caged fishing activities and close proximity to houses on stilt.

• About 2 km south of the construction area there are also on extensive area for cockeral cultivation.

Seabed Condition Teknik Lengkap Geohydrographics Sdn Bhd performed

the geophysical survey in December 1998 for the proposed route. However, a pre-installation route survey was again conducted in May 1999. Generally, the soil is soft grey marine clay (mud) accumulated especially in the shipping channels. The remainder is light grey, fine to medium grained sand with shell fragments especially towards the shore and sandbanks. The seabed reaches a depth of nearly 16 m at the shipping lane. The Middle Bank nearer to Gelugor cm the Penang Island mainly consists of mud. During transition phase of low and high tide, the current turbidity around the Middle Bank create a fast action reaction. This is further worsen by the "venturi" effect of the Straits of Penang and the Prai River deposits. Two small islands had resurface near the Penang Bridge after the construction of the bridge and the reclaimation activity near by. This is the result of the above phenomena where bottom profiles slope reduce the rate of deposition increases and the material pile-up to form an island. The Prai River makes the matter worse where strong undercurrent makes the diving activity very difficult. Neap tide is the only time where diving could be perform excellently.

Mass Gravity Flow (Seabed profile) Mass gravity flow on the seabed can develop as a

consequence of soil instability. The general term covers three types of gravity flows: mudslides, debris flows and turbidity currents. Mudslides most likely occur in clay soil where it is the resultant of coherent failure of the slqpe. This mudslide may disintegrate into debris flow where it is characterized as a dense fluid consisting of different sizes of suspended particles. This form of loading on a pipeline is less severe compare to mudslide but it can reach a certain distance. Larger particles fail out of suspension as the debris flow progress and upon achieving properties of "dense water" form into turbidity current. This type of current is more likely to develop in areas

of sandy or particulate soils. As turbidity currents develop it increases in momentum, eroding further sediments. At the Prai river mouth, sand waves and ripples up to lm high developed as the tide changes.

SURVEY ACTIVITIES The objective of the survey includes:

• To accurately determine the water depth (bathymetry) along the Pipeline Route, producing a seabed profile, which would be used as a baseline for the trenching and burial works during the installation of the NPS 24 gas pipeline.

• To determine and map out any seabed or shallow sub-seabed obstructions or anomalies along the Pipeline Route, which may pose as a constraint to the installation of the NPS 24 gas pipeline. This would be performed with a side scan sonar and sub-bottom profiler.

A total of five (5) longitudinal survey lines centered at the NPS 24 PGU HI Gas Pipeline Proposed Route (original route) was designed and surveyed. The line spacing is 25 meters forming a survey corridor of 100 meters wide. Cross lines were run at every 500m interval, extending to about 250 meters south of the Proposed Route. Specific mobilization tasks carried out during this period included the following:

• Wet testing of temperature / salinity / depth probe. • Appropriate rub and wet testing of the side scan sonar

system. • Installation and interfacing testing of all computer system. • Running of software (on-line and bathymetric data

acquisition) • Measuring vessel offsets twice and independently. • Safety instructions I briefing

In summary, two large channels in North-South namely the Middle Shipping Channel (KP 2.250 - KP 3.200) and western channels (KP 5.200 - KP 5.800) characterize the seabed profile. Maximum water depth observed within the Middle Shipping Channel is 15.7 meters (below Chart Datum, CD) at whilst the maximum water depth observed within the western channel is 9.7 meters (below CD). In between these channels lies the Middle Bank, from KP 4.200 to KP 5.130, over a distance of 930 meters along the Route. The Middle Bank has an average height of 0.5 meters above CD, which dries during low tide. An area of shallow water was observed in the Eastern Bank with a minimum water depth of 2.7 meters (below CD) at KP2.14. The edges of all the sand banks presence within the survey corridor has an average gradient of 1 in 10. An area of irregular seabed, which is thought to associate with cemented shell build up, is observed between KP 5.300 and KP5.430.

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Side-scan sonar records reveal distinctive areas of low to medium sonar reflectivity. Low sonar reflectivity is associated with very soft clayey seabed, whilst medium sonar reflectivity is associated with fine to medium grained sand. The seabed morphology is dictated by the current, flow in North-South direction, and tide conditions within the Straits of Penang. The sandy seabed is characterized by the areas of sand waves and ripples observed within the survey corridor. A few patches of high sonar reflectivity associated with possible cemented shell build up, of height ranging from less than 0.3 meters to 1.5 meters, were observed between KP 5.400 and KP 5.450. Numerous patches of high sonar contact are observed within the Middle Bank. They are thought to associate with mounds of stiff to hard sediment, with diameter ranging between 0.5 meters and 1.5 meters and is generally of less than 0.3 meters in height.

The sub-bottom profiler (pinger) data generally reveals a series of well-defined sub-horizontal to cross bedded sediment sequence. The seabed sediment is thought to comprise mainly of sand, which changes to clay towards both Prai and Gelugor Landing Point. The lower interval of pinger record is characterized by a series of well-defined channel development and erosion sur£ace. Channel in fill sediments is thought to comprise mainly of firmer clay and sand with organic material. Diffraction is occasionally observed at the base of the channel indicate the presence of biogenic gas, which is associated with decomposition of organic materials within the channel. Diffraction coupled with partial to total masking of underlying horizons is also observed between KP 0.000 - KP 0.400, KP 3.600 - KP 3.800, KP 5.000 - KP 5.200, KP 5.380 - KP 5.470 and KP 5.900 - KP 6.000. They are associated with possible cemented shell build up or dense sand layers with podcets of firm silty / sandy clay to dense coarse sand.

Besides that, the geotechnical evaluation used cone-penetrometer tests (CPT), hydraulic coring, and box coring, vibro-coring and piston gravity coring for soil sampling. Information on the preliminary pipeline route was made available to the client by other data i.e„ Ikram, Penang Port and the Marine Department. An environmental impact assessment was also perform to meet the relevant authority requirement. A highly extensive and iterative exchange of information was achieved between all concern parties contributing to the successful route selection process.

PIPELINE DESIGN The Gelugor Mainline design has adopted an extensive

design approach to ensure the pipeline was constructed to the best of engineering practice. Some of the pipeline design criteria adopted for the project are as follows:

• Wall thickness, buckling and collapse analysis. Highest Astronomical Tide (HAT), inclusive of surface wave

height is used in the design for both installation and operational condition.

• Spanning analysis. Since the pipeline is post trench and Horizontal Directional Drilling (HDD), this analysis is perform for the installation and hydrotest cases where freespans may result from laying the pipeline onto uneven seabed.

• In-situ stress analysis. Both fully restrained and unrestrained pipeline section conditions were investigated here.

• On-bottom stability analysis. An installation condition (pipeline empty) subjected to 1 year return period wave and current was included here.

• Pipeline expansion analysis. Both operating and hydrotest cases plus expansion offset was investigated which include the following basis: no axial restraint at the end of the pipeline, maximum operating temperature, minimum installation temperature, design pressure, low (realistic) estimation of axial friction and minimum content densities where applicable

• Pipeline installation analysis. This includes pipelay initiation, abandonment and recovery analysis.

• Cathodic protection design. Design to cater for minimum design life of 25 years and pipe to soil potential between -0.8 and - l . l v (silver/silver chloride reference cell)

• Pipe supports design inclusive of maximum pipe load together with environmental (wind) loading.

• Rock armoring or rock cover. The design involves in selecting the right rock size plus the filtering layer around the pipe prior to it.

• Impact analysis. This is to determine the approximate required rock cover thickness due to impact load associated with the transfer of energy from the impacting trawl board to the pipe and its coating. The impact direction and the amount of energy transfered to the pipe depends on the pipe diameter, span height, shape of the front of the trawl board/anchor and the direction of travel relative to the pipeline.

PIPELAY VESSEL The pipelay vessel for the project was built partly from

sketch. It requires an overlapping vessel concept between offshore application and shore approach. The barge is a non self-propelled 'make-up' flat top barge design for working in the area. The pipe lay vessel chosen requires less tension load thus widen the choice of vessel for installation. Lower pipeline tension has the benefit of lower pipeline residual tension which leads to a shorter pipeline unsupported spans and reduction in the risk to the installed pipeline. An elevated pipe lay ramp was fixed on the starboard side and runs along the entire length of the barge. A fixed 24 m stinger section is attached to the stern to support the pipe overboard region. The barge has 3 welding stations arranged for maximum 15 m long pipes with

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no pipe tensioning capacity. Pipes are loaded from the port side of the barge using a 136 ton crawler crane. Using a boom length of 140 feet, the crane loads the pipes and moves it to the ready rack. It is transferred onto the bead stall for beveling and to the stalking (line up) station. The details of the pipelay vessel used for the project are as per Figure 3 below. The pipelay vessel also included A-davit for tie-in purpose, cabins which function as offices, NDT viewing facilities, compression chamber, cooking area and the relevant welding stations inclusive of radiographic examination area and mastic application area.

PIPELINE INSTALLATION METHODOLOGY Initially, the contractor plan to execute the work by perforating the fabrication work i.e. welding, NDT, pretest etc. onshore (at 3 locations). Upon completion of a certain section, the pipe will be towed out to the designated location for the next activities i.e. pulling into the respective Horizontal Directional Drilling (HDD) hole which was prepared earlier, trenching and jetting at the marine spread and finally tie-in prior to commissioning. However, upon contract award and details discussion with relevant authority i.e. Penang Port, the contractor found out that there are safety, space and time constraint for them to perform the onshore fabrication and towing out activity. This include an area to string and weld the pipe to a certain length, platform/jetty having the proper strength and safe enough for it to withstand the high hydrotest pressure (pretest). It should also be near enough to be easily towed out offshore plus the hindrance that it had on the marine traffic in and out from the port. The other is the difficulty they encountered which was tide dependent (the existence of the middle bank) and the numerous anchoring along the Non Anchorage Zone; the construction methodology was then

revised to include pulling of the pipeline via a pull winch barge accordingly.

A pipeline installation methodology based on a lay barge pulling operation activity concurrently with HDD activity and post trenching activity at a later stage was implemented. For the shore approach, once a section of the pipeline in completed it will be towed out to the respective HDD hole and pull into it. The pipeline will be partially filled with water via an insertion of a HDPE pipe inside the steel pipe to ensure the pipe is not buoyant. The fabrication area will be on the lay barge and the pipe string will be pulled accordingly until a section spread is completed prior to towing out. A total of three (3) above water tie-ins' were perform for the 7 km stretch.

By implementing the revised construction methodology, the contractor has managed to achieve the same result in comparison to having the fabrication work onshore. The pipe fabrication activity on the lay barge is an independent activity prior to having any effect to the shipping movement across the shipping lane in the port area as previously identified.

Horizontal Directional Drilling fHDDl There are initially three HDD areas to be perform, each at

the shore approach and one across the shipping lane. However the construction methodology changes during the construction stage where only the shore approach part was materialized. HDD in the pipeline industry may be defined as a technique enabling the laying of a pipeline under a land surface obstacle. This is accomplish by drilling a directionally controlled hole to accommodate the pipe, along a predetermined curved path under the obstacle and drawing a pre-joined, coated and tested pipe-string back through the hole. The technique is now well understood and widely practiced by specialist contractors available worldwide. Crossings for pipelines up to 42 inch diameter have been successfully completed. The longest recorded 18 inch diameter HDD pipeline crossing is more than 1700 meters in length. The Prai HDD was supposed to be an NPS 20 1600m long but the distance was cut short to only 650 m long after three unsuccessful trials. However, the Gelugor HDD 1100 m was successfully completed.

In sand, loam or softer clays the drilled hole may be achieved by jetting. The jetting tool at the leading end of a drill string has a beveled face with mud jets strategically placed to favor material removal on one side in preference to the other. Spoil is removed from the hole by mudflow. In order to produce a straight portion of hole the complete drill string is uniformly rotated. To initiate a curve the drill string is held in the preferred rational allowing the jet tool, in conjunction with tool thrust, to establish and sustain the required curve. The required a hole for entry and exit points for the shore approach and intervening ground surface are surveyed before any drilling is commenced. This data governs the design of the drill in both plan and elevation which is carefully planned to ensure that the minimum radius of curvature is acceptable for

PRINCIPAL Classification ABS PARTICULARS Port of Registry Singapore

Year of 1994 Built Singapore

CONSTRUCTION Length Overall 252 ft DETAILS Breadth Molded 80 ft

Depth Molded 6ft Deadweight 5990 MT GRT/NRT 2371/712 Deck Loading 7.5 MT/SQ Hull Type/No. Of 2-Longtitudinal Bulkheads 5-Transverse

DECK 1 Set Diesel-Powered Anchor EQUIPMENT 1 Pc Stockless Anchor

SMT Towing Brackets - 4 Sets fable 2: Details of the Shallow Water Lay Barge

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both the pipe to be inserted and the drilling process. Here 500D is the required minimum radius.

To ensure that the drill path adheres to the design as closely as possible and to provide position and directional data during drilling, the driller uses a down-hole survey tool which is located in the drill string behind the bit and motor. At regular intervals during drilling a reading is taken from the survey tool to provide the position of the instrument relative to the drill entry point. This position is compared by specialized computer software to the pre-entered design path thus allowing corrective action to be taken by the drilling superintendent when appropriate.

Here, some of the benefit of using HDD is as follows:

• Avoidance of environmental disturbance in construction, i.e. rearing of caged fishing activity and houses on stilt.

• Enable some crossings not previously possible. • Increase the number of alternative pipeline routes

available. i.e. shore approach at both power plants. • Improve security for the completed crossing (against

natural and third party hazards). • Provide overall cost reduction.

Anyway, the lesson learnt in this particular project is to have more soil samples and test at closer intervals to determine the soil condition accurately.

Post Trenching over the Mud Bank Initially, the jetting/eduction machine was proposed to be

use here. However due to accessibility problem encounter here where the area is only accessible during high tide, the usage of the above machine is restricted due to insufficient water level. Barges available are also found to be too large and/or with deep draught which is difficult to handle besides the close proximity to the non-anchorage zone. Finally, the contractor through their post trenching subcontractor Sumai Engineering Sdn Bhd adopts the use of a cutter suction pump catamaran. See Figure 5 & 6 below on the equipment use over the mudbank. Here, once the trenching machine is lowered on to the pipeline using mechanical hoist with divers assistance, the jetting pump is started followed by the suction pump. The catamaran can move approximately 0.5 m above seabed level. With a water depth at maximum tide recorded between 1.0 to 1.5 m. A trench of about 0.5 m cover was achieve in a single pass. A total of four passes were required to meet the contract requirement.

CONCLUSION There are a few technological advances related to

submarine pipeline laying in shallow water applies here namely the usage of shallow water barge for laying and pulling activities, the Horizontal Directional Drilling and the post trenching activity. All this allows to a considerably decrease in

operational time, reliability and operability. The know-how associated with laying pipeline in shallow water has further enhanced the knowledge in the field of the local contractor. It has also allowed the optimizing of local engineering and subsequently the construction far beyond expectation. The usage of advance survey equipment has nessitate early identification of problem areas. The successful completion of this extremely difficult project was due to the excellent performance of all suppliers and contractors, especially Pi Gas Engineering, Mentor Engineering, Sumai Engineering, Bill Finger Berger Drilling Co., and others.

ACKNOWLEDGMENTS Tuan Ifl. Mohd Sohaimi Ahmad, Project Manager, Penang

Lateral Projects, PETRONAS Gas Bhd. OGP Technical Services Sdn Bhd. En.Sidek Atan, Project Manager, Pi Gas Engineering Sdn

Bhd.

REFERENCES 1. 8th Offshore Pipeline Engineering Course, Kuala

Lumpur 1998. 2. DNV, "Rules of Submarine Pipeline Systems, 1981" 3. DNV, "Rules of Submarine Pipeline Systems, 1996" 4. DNV, "Recommended Practice Cathodic Protection

Design, 1993" 5. Environmental Statement For The Proposed PGU IE -

Prai Lateral, Gelugor Mainline and Gelugor Meter Station, Biro Rundingan, Universiti Kebangsaan Malaysia.

6. Teknik Lengkap Sdn. Bhd. TL Report No. MAL-072 Rev. Ola (Survey Report).

. PI GAS Billfinger Civil Construction Company procedure and calculation (Confidential)

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Figure 1: Location Plan

ROUTE ROUTE SELECTION SURVEY

Route Selection

Study.

Design Basis for Route Selection

Feasibility Suvey.

SPECIALIST STUDIES

Environmental Assessmeri

Geotechnical Survey & Soil

Test

PIPELINES DESIGN

CONSTRUCTION COIUMISSIOHIHG

Front-End Engneering & Basic Design.

Detail Design.

Horizontal Directional

Drilling

Laying

Tie - In

Hydrate sting

Commissioning

Post Trenching

Rock Armonring

Figure 2: Main Activities for Gelugor Mainline Project

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Figure 3: Lay Barge Arrangement Including Welding Stations

Figure 4: A-Davit and Stinger Diagram

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Figure 5: Catamaran Rigging Up

k Cm * 11

FISSSSSW

Figure 6: Catamaran In Action at The Mud Bank

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IPC2000-238 - ASME Digital Collection

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