FA2012

COVER STORY

David A. DouinExecutive Director

Richard L. AllisonAssistant Executive Director Administrative

Charles WithersAssistant Executive Director Technical

Paul D. Brennan, APR Director of Public Affairs

Wendy WhitePublications Editor

Brandon SofskyManager of Publications

BOARD OF TRUSTEESJack M. Given Jr.

ChairmanJoel T. AmatoFirst Vice Chairman

Gary L. ScribnerSecond Vice ChairmanDavid A. DouinSecretary-TreasurerJohn BurpeeMember at Large

Christopher B. CantrellMember at Large

Donald J. JenkinsMember at Large

Milton WashingtonMember at Large

ADVISORY COMMITTEEGeorge W. Galanes, P.E.Representing the welding industry

Lawrence J. McManamon Jr.Representing organized labor

Kathy MooreRepresenting National Board stamp holders

Brian R. Morelock, P.E.Representing boiler and pressure vessel users

Peter A. MolvieRepresenting boiler manufacturers

Michael J. PischkeRepresenting pressure vessel manufacturers

Robert V. WielgoszinskiRepresenting authorized inspection agencies

(insurance companies)

The National Board of Boiler and Pressure Vessel Inspectors was organized for the pur-pose of promoting greater safety by securing concerted action and maintaining uniformity in the construction, installation, inspection, and repair of boilers and other pressure vessels and their appurtenances, thereby ensuring acceptance and interchangeability among jurisdictional authorities empowered to ensure adherence to code construction and repair of boilers and pressure vessels.

The National Board BULLETIN is published three times a year by The National Board of Boiler and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, Ohio 43229-1183, 614.888.8320, nationalboard.org. Postage paid at Columbus, Ohio.

Points of view, ideas, products, or services featured in the National Board BULLETIN do not constitute endorsement by the National Board, which disclaims responsibility for authenticity or accuracy of information con-tained herein. Address all correspondence to the Public Affairs Department, The National Board of Boiler and Pressure Vessel Inspec-tors, at the above address.

2012 by The National Board of Boiler and Pressure Vessel Inspectors. All rights re-served. Printed in the USA. ISSN 0894-9611. CPN 4004-5415.

FEATURES 3 2012 Registrations

4 Safety on Trial 75 - Ton Bottle Rocket Case Study

8 Phased Array Ultrasonics Now Replacing Radiography for Small Bore Piping Welds

12 A Collection for the Gages14 Testing... What's Not to Love? A tough world needs tough tests

16 Boiler External Piping (BEP) Part 2 Feedwater Piping

Executive Directors Message

Inspectors Insight

Pressure Relief Report

Updates & Transitions

Profile in Safety

Training Matters

Training Courses and Seminars

The Way We Were

DEpARTmEnTS2

6

20

3032

34

35

36

Testing... Testing... 1, 2, 3... Expansion Project Complete, It's Full Speed Ahead at the National Board Test Lab

COnTEnTS FALL 2012VOLUME 67 NUMBER 3

On the Cover:powered up and ready to go: the test labs new three-in-one everyday workhorse air testing system is a highlight of the 2012 expansion project.

Please RecycleThis MagazineRemove Cover And Inserts Before Recycling

nationalboard.org

Test lab staff hosts representatives from Weir Power & Industrial who were on hand to witness their steam valve testing on August 1.

22

22

In this issue, we are pleased to bring our readers a story long overdue. I say long overdue because many in our profession dont often think of the Test Lab as being a component of the National Board.

Fact is, it is a very important component.

I subscribe to the notion the safety valve and other

pressure relief devices are the most critical parts of all pressure-containing items. Without these devices, pressure equipment becomes potential bombs. With these elements, operators today can be assured there is little guessing when operating controls fail and pressures reach critical levels.

Yet, curiously, these equipment devices are often overlooked. When invented by Denis Papin in the late 1600s, the safety

valve was revolutionary. Although materials and designs have evolved over centuries, Papins basic concept has endured. The fact pressure relief devices are today employed on just about every piece of pressure equipment underscores universal and critical importance.

And thats why the National Board Lab is integral to the pressure equipment industry. Since 1974, it has tested thousands upon thousands of pressure-relief devices, thus helping to ensure the quality of safety valve manufacture and repair.

Each year hundreds of manufacturer representatives visit the lab in Worthington, Ohio, to measure the performance of their company's pressure-relieving equipment.

Here, pressure relief devices are independently evaluated for function and capacity. Devices meeting standards and specifications of new construction allow the manufacturer to

apply the National Board NB capacity certification mark for new equipment. Testing is also conducted to assess a companys skill and aptitude in repairing pressure relief valves. Qualifying organizations become accredited to stamp the National Board VR symbol on repair nameplates.

Capacity certification by the National Board Test Lab

denotes equipment designs have been independently reviewed

and tested, and that a companys quality system has been audited. More important, it means the certified equipment meets

internationally-recognized standards.Recently, demand for National Board lab services has been

such that it became necessary to expand the testing area by nearly 3,000 square feet. The addition of new test components and upgrades to support equipment will accommodate increased work volume and accelerate response to certification customers.

While testing is the primary focus, the lab also actively supports industry research and development by testing new designs. Additionally, it validates new concepts and serves as a comparative standard for other laboratories.

The lab has also been instrumental in assisting jurisdictions with accident investigations by providing important testing to evaluate equipment failure.

The article on page 22 is the most comprehensive yet on the Test Lab. Readers will not only gain insight regarding the testing process, they will get a rare look at what takes place behind the walls of this vital National Board facility.

When Papin created the first safety valve nearly four

centuries ago, it was to protect him from the potential explosion of a digester he constructed. While his action addressed an immediate problem (i.e., his safety), little did he understand the impact his new invention would have on the world.

The safety valve is the one component that often determines whether a pressurized device continues to perform the work for which it was intended, or becomes an instrument of unharnessed energy.

While the National Board Test Lab fully embraces its coveted role as one of the worlds most vital testing facilities, its function can never be understated.

The work performed here touches the lives of anyone who comes into close proximity of pressure equipment.

And that is all of us. Every day.

Performing Under Pressure The Validation of ValvesBy DAViD A. Douin, EXECuTiVE DiRECToR

2 NATIONAL BOARD BULLETIN FALL 2012 NATIONALBOARD.ORg

ExEcutivE DirEctor's MEssagEDEPartMENt

3FALL 2012 NATIONAL BOARD BULLETIN NATIONALBOARD.ORg

FEaturE BuLLEtiN

nuCLEAR VESSELS

in square feet 10 (A) 443 482 481 494 700

> 10 and 36 (B) 79 51 30 38 98

> 36 and 60 (C) 9 14 7 13 19

> 60 and 100 (D) 6 18 5 5 27

> 100 (E) 169 94 14 9 19

TOTAL 706 659 537 559 863

PRESSuRE VESSELS

in square feet< 10 (A) 927,192 788,752 680,873 774,899 819,791

> 10 and 36 (B) 207,621 202,902 183,449 214,107 338,811

> 36 and 60 (C) 44,401 40,017 35,798 43,648 59,371

> 60 and 100 (D) 16,162 12,924 11,039 14,714 14,983

> 100 (E) 21,189 16,784 13,783 18,509 18,239

TOTAL 1,216,565 1,061,379 924,942 1,065,877 1,251,195

FY 2012 FY 2011 FY 2010 FY 2009 FY 2008

BoiLERS

square feet of heating surface

55 (A) 163,189 154,964 156,129 161,041 156,766

> 55 and 200 (B) 28,591 28,823 30,884 32,371 39,115

> 200 and 2,000 (C) 8,281 8,362 8,032 9,084 10,680

> 2,000 and 5,000 (D) 607 557 420 720 689

> 5,000 (E) 475 572 650 766 1,021

TOTAL 201,143 193,278 196,115 203,982 208,271

2012 RegistrationsNational Board Certificate of Authorization to Register ensures a third-party inspection process, provid-ing for uniform acceptance of pressure-retaining equipment by member jurisdictions. This important safety process is documented via submission of data reports by the manufacturer to the National Board. These are the only reports carrying the National Board registration number. Once registered, each report is maintained in a permanent

*An attachment is any type of additional information to be submitted with the primary data report.

For more information on the Authorization to Register Program, access the National Board website at

ATTACHMEnTS* 103,175 92,158 90,117 86,961 103,336

GRAND TOTAL 1,521,589 1,347,474 1,211,711 1,357,379 1,563,665

file by manufacturer name and National Board number.

The list below identifies boiler, pressure vessel, and

nuclear vessel registrations by size for the past five fis-cal years. The National Board fiscal year is from July 1 to

June 30.

The total number of registrations on file with the

National Board at the end of the 2012 reporting period was 48,582,839.

SiZE

An autoclave is a device in which objects are heated predominantly by steam, but sometimes electrically, for sterilization, cooking, or curing, among other uses. Large autoclaves are used in many industries, including aerospace, medicine, food and beverage, and concrete block manufacturing. Inspectors frequently encounter autoclaves of all shapes and sizes during routine inspections. From the local tattoo parlor, dentistry office, or manufacturing plant,

to a hospital or veterinary clinic, autoclaves are utilized every day in society.

Because of the powerful pressures at which autoclaves operate typically 35 pounds force per square inch gage (PSIG)

to 150 PSIG they must be carefully inspected and maintained

for obvious safety reasons. The following account is a case study of a large autoclave that malfunctioned and caused substantial property damage in a Southern city in early May of 1988. The unit, approximately 11 feet in diameter, 97 feet long, and enclosing a volume of about 9,200 cubic feet, was used for curing concrete blocks. Concrete blocks can be air-cured or cured in a steam autoclave, which greatly shortens the curing time and reportedly improves the mechanical properties of the blocks.

CAuse ANd effeCT

The incident occurred during the late evening/early morning hours. The locking mechanism of the autoclaves main loading door failed while the unit was pressurized with 125 PSIG steam. The autoclave instantly became a 75ton bottle

rocket and launched itself out of the building, destroying it. It traveled approximately 100 feet down an embankment and landed straddling some railroad tracks. Fortunately, this incident happened during non-working hours and no one was injured or killed. Neighbors reported the explosion sounded like a bomb going off and that their houses shook. Damage included one destroyed autoclave and the building it was housed in, collateral damage to adjoining equipment, and minor damage to the railroad tracks. One can only imagine if a tanker filled

with anhydrous ammonia, nitrile, or liquefied natural gas was

sitting on the tracks at time of impact.The autoclave looked like a large steel test tube with the

loading door on one end and a semi-hemispherical head on the

other. The steam inlet was on top of the door end, and the valved exhaust vent on the closed end. The door was hinged on the right as one enters the clave, and was supported by large davits not unlike those seen on large firetube boilers commonly in service.

The main hinge was about 3 in diameter. The door-locking mechanism consisted of a square metal bar bent into a circular shape. A steam valve and cylinder on the locking mechanism expanded the metal bar into matching grooves in the door and the jamb located on the autoclave body.

To load the autoclave, fork trucks would drive over the threshold and move the pallets of uncured blocks into the unit. The most probable cause of this explosion was that the operator/loader did not completely clean debris from the bottom of the locking groove in the autoclave body. This prevented the locking ring from completely engaging, and the pressure (125 PSIG) / force (1.7 MM lbs.) acting on the door

distorted the ring enough so that it yielded. The force of the door blowing off sheared the hinge pin at the top and bottom. The energy content of the steam in the autoclave was about 3.4 MMBtu, equivalent to nearly 2,000 pounds of dynamite.

The owner filed an insurance claim for the property damage

and resultant production and revenue losses. The insurance carrier denied the claim based upon an explosion clause in the policy. Interestingly, this case revolved more around the definition

of the word explosion than what actually caused the explosion. My involvement in the case consisted of trying to determine the


FEaturEBuLLEtiN

Safety on Trial75-Ton Bottle Rocket Case StudyBy Rick Smith, P.E.

Damage as seen from railroad tracks.

cause of failure and to determine if this was an explosion. Since litigation occurred before Internet use was widespread, I spent several hours at the Columbus Metropolitan Library researching all the dictionaries I could find on the definition of explosion.

Even though it has been over 20 years, this definition is burned

into my memory: Explosion the sudden, violent release of energy whether chemical, electrical, mechanical, or nuclear.

In my mind, this event was clearly an explosion. The explosion is what caused all of the damage. But what caused the explosion most likely debris left on the bottom of the locking groove due to operator carelessness was another issue entirely. However, the cause of the explosion was not adjudicated in this case because the parties settled before it went to trial.

ImpORTANCe Of INspeCTION

Regular inspection and maintenance of pressure equipment is the first line of defense for preventing this type of incident from

happening and for ensuring a safe work environment. This case study is a sobering reminder of the devastating consequences of unchecked pressure equipment and careless operation and maintenance. It is extremely fortunate this was a property damage incident only and that people were not hurt or killed. Had there been a railroad tanker full of hazardous, toxic, or flammable

materials when the autoclave launched on its horizontal trajectory, this incident could have caused mass casualties.

When inspecting large pressure vessels, such as the autoclave involved in this case, inspectors will typically:

closely examine the vessel and safety valve(s).inspect the closing, locking, and hinge mechanisms for wear and corrosion.carefully check any locking grooves, cutouts, or similar fea-tures for debris build-up or unusual wear patterns.

It is imperative that operators and management be informed about the importance of:

keeping locking grooves clean. properly cleaning, lubricating, and maintaining locking mechanisms.frequently checking the lock integrity.

Additionally, the safety valve inlet should not be occluded by pallets or product during operation.

Large autoclaves also have a somewhat unique operational issue that can have a huge negative effect on boilers. When a large autoclave is filled with cool or cold product and closed

up, the operator typically does not alert the boiler house that a huge load swing is coming. The operator will typically open a 2 or 3 high pressure steam valve as quickly as possible in some cases this is a quarter turn ball or butterfly valve. The

resulting instantaneous load spike can easily shut the boiler(s) down on low water, as well as cause serious water hammer due to carryover and priming.

There are four ways to prevent this type of boiler upset:1. Train and supervise the autoclave operators to open the

main steam valve slowly. This may be very difficult in

actual practice.2. Put slow-opening valves on the steam inlet to the autoclave.3. Make sure the boiler level controls are VERY well-tuned,

particularly on the feed forward signal from the steam flow

meter.4. Use a differential pressure or flow control valve on the

boiler header to limit the instantaneous steam flow.

Rick Smith has been working with boilers for 35 years. He is

president of Applied Thermal Engineering, Inc., a central Ohio firm

specializing in industrial utilities and forensic engineering. He has been

an expert witness in numerous boiler explosion and carbon monoxide

cases and has taught hundreds of boiler and HVAC classes. He can be

reached through his website at www.ate-inc.com.

Damage as seen from the side street.


Fillet welds are very basic to most industries, but especially to the world of pressure-containing items. Every code we follow has rules defining fillet

welds. They are to be found on every welded

nozzle, slip-on flange, socket welded fitting,

and lap joint.

Example 1:

Typical sample of a coderequired fillet weld sizing calculation.

(See Section I, Fig. PW-16.1 (d), Section IV, Fig. HW-731(d), and Section VIII, Div. 1, Fig. UW-16.1(l) ).

Let: t = 0.5 in. (13 mm) and tn = 0.375 in. (10 mm)

tmin = minimum( t, tn, 0.75) = minimum( 0.5, 0.375, 0.75) = 0.375 in.0.7 tmin = 0.7 . 0.375 = 0.2625 in.t2 = minimum(0.25, 0.7tmin) = 0.25 in.t1 = maximum( (1.25 . tmin) t2), 0.25) = maximum((1.25 . 0.375) 0.25), 0.25) = 0.25 in.

tn

t2

t1t

t1+ t2 1 tmin.

tmin. = minimum (t, tn, 0.75)

t1 and t2 shall each be not less thanthe smaller of in. (6 mm) or 0.7 tmin.

t = vessel shelltn = nozzle wallt1 and t2 = filletweld throat dimensions

Why dO We use fILLeT WeLds?

The ASME Boiler and Pressure Vessel Code (ASME B&PVC) places considerable importance on fillet

welds. They are not something to cover gaps or hide a groove weld. Fillet welds serve a number of important purposes, which when done correctly, greatly improve construction.

In ASME Section I, PW15.1.2, for example, the

fillet weld strength is based on onehalf the area subject

to shear forces, computed on the average diameter of the weld. In addition, PW15.2 provides a value of 49%

for a fillet weld in shear to be used in establishing the

allowable stress value for the weld metal. Even small seal welds used on rolled tubes

provide considerable added strength. The size and shape of fillet welds used to attach nozzles provides

the additional benefit of controlling local stress

intensification within the nozzle.

For the most part, fillet welds are 45 right

triangularshaped welds defined by two legs

measured from the weld root or intersection point. The ASME B&PV codes calculate the weld throat, which is then used to calculate the weld leg, as shown in Example 1.


It's Just a Fillet WeldBy RoBERT SCHuELER, SEnioR STAff EnGinEER

iNsPEctors iNsigHtDEPartMENt

In Example 2, both t1 and t2 have solved a 0.25 in. (13 mm) minimum throat dimension.

Solving the minimum weld leg for either t1 or t2 will solve 0.25 1.4142 = 0.354 in. or round up to 3/8 in. (10 mm) leg. The weld size information is normally transmitted to the welder in the form of a welding symbol shown in Example 3, which in this case would look like the following:

example 3:

Once the weld size is determined, the required information is then transmitted to the welder, who is expected to produce the weld of the proper size. This brings us to the main question at hand. How do we know this is done correctly? The simple answer is to measure the weld, but how?

measured dimensionst1 and t2 shall each be not less thanthe smaller of in. (6 mm) or 0.7 tmin.

a

b

c

B

A

C

45

45 90

aWeld Leg

Weld Throat

bc

A

B

C

c = a2 + b2 a = c2 - b2 b = c2 - a2

Let a = b =1.0 ThenWeld Leg = Weld Throat . 1.4142Weld Throat = Weld Leg / 1.4142

Example 2: Right Triangle(typical fillet weld shape)

c = 2 = 1.4142

3/8 Leg

3/8 Leg

3/8 Leg

3/8 Leg

As normally shown on a detailed drawing in the form of an AWS standard welding symbol.

Cross-section through nozzle,shell, and welds showing filletweld legs.

Photo courtesy of G.A.L. Gage Company

Example 4 shows one type of weld gage that measures fillet weld legs and weld convexity. The following illustrations

demonstrate how simple it is to use a weld gage like the one shown in Example 4. The first and second illustrations measure fillet

weld legs. The third illustration measures the throat dimension of the weld.

Typical Weld Gage

Why TAke The TIme TO meAsuRe The WeLds?

Isnt it just good enough to look at the weld? A practiced eye is a good thing; however, should a weld prove to be undersized, this would result in considerable added costs for additional welding and possibly additional postweld heat treatment. In the case of fillet welds, larger is not better. The

addition of extra weld metal is both expensive and could lead to the introduction of defects.

Either condition should justify having and using fillet

weld gages on a regular basis. They are quick and easy to use and can eliminate problems.


measurement of Vertical fillet Weld

Leg dimension

measurement of horizontal fillet Weld

Leg dimension

measurement of fillet Weld

Throat dimension

Example 4:


FEaturEBuLLEtiN

Phased Array Ultrasonics Now ReplacingRadiography for Small Bore Piping WeldsBy Mark Carte and Michael Moles, Olympus NDT

Phased array ultrasonics is steadily replacing radiography for construction weld inspections, in particular, using encoded scanning. An encoder is a device that coordinates distance with recorded digital data for storage in a computer, unlike conventional ultrasonics. Encoding permits auditable, repeatable scanning with additional sizing capabilities. The encoder has a resolution of 32 steps/mm, which is plenty for inspection of welds. Portable phased arrays offer significant advantages

over radiography for detection, sizing, imaging, and characterization of defects in welds. Unlike conventional ultrasonics, phased arrays (PA) use electronically-controlled time delays to sweep, steer, and focus beams. Arrays are similar to conventional transducers, but are sliced into small elements for phasing. It is easy to change either arrays or the contoured wedges.

Phased array probes typically consist of a transducer assembly with anywhere from 16 to as many as 256

small individual elements that can each be pulsed separately. These may be arranged in a strip (linear array), a ring (annular array), a circular matrix (circular array), or a more complex shape. As is the case with conventional transducers, phased array probes may be designed for direct contact use, as part of an angle beam assembly with a wedge, or for immersion use with sound coupling through a water path. Transducer frequencies are most commonly in the range from 2 MHz

to 10 MHz. A phased array system will also include a sophisticated computer-based instrument that is capable of driving the multi-element probe, receiving and digitizing the returning echoes, and plotting that echo information in various standard formats. In general, performing a PA inspection is fairly straightforward. Equipment and training are available, so the major emphasis is on correct setups and interpreting the results.

The ASME Boiler and Pressure Vessel Code Section V, Article 4, has published rules for performing phased array ultrasonic inspections of welds. Besides being safer and more repeatable, PA systems are faster for high-volume weld inspections. These inspection devices can be used for a number of different applications where small bore piping placed in close proximity creates an inspection challenge. In many cases, defects can be clearly identified and characterized,

and locations mapped. This article will describe some results obtained during testing.

AdVANTAGes Of pA OVeR TRAdITIONAL uLTRAsONIC

TeChNIques

Phased arrays offer significant

advantages in speed, imaging, data auditing, and flexibility over

traditional ultrasonic techniques. Not surprisingly, encoded phased arrays, either mechanically or semi-mechanically driven, have become

a serious competitor to radiography testing (RT) for welds.

Radiography testing has been the standard for weld inspections for the last several decades; however, it has known limitations. Specifically, RT

has major safety issues from radiation, licensing issues from the same problem, work disruptions, environmental and chemical wastes, large volumes of film,

and film deterioration. Defect analysis

can be subjective and quite slow. In addition, RT is unable to reliably size defects in the vertical plane for structural integrity, and is poor at detecting planar defects. In contrast, there are no safety or licensing issues, film deterioration, or

storage issues with PA. Phased arrays can size defects in the vertical plane, within known errors. The inspection speed is generally a lot higher when using encoded linear scanning. Probability of detection (POD) is improved using multiple angles and imaging, and results are fully auditable when encoded. (1, 2)

Timeofflight diffraction (TOFD) is

the other common automated ultrasonic testing (AUT) technology and has been covered by ASME (3) since 2004. TOFD uses two transducers in a pitch-catch arrangement and measures arrival times and defect sizes to high accuracy. However, the main problem with scanning small-diameter pipes occurs when wall thicknesses are less than ~10 mm (3/8). When this happens, TOFD becomes less useful as the dead zones at the outside diameter (OD) and inside diameter (ID) dominate the wall thickness.


INdusTRy AWAReNess

Most design engineers , procurement personnel, and outage planners have not recognized that compared to RT, PA has the ability to reduce overall cost in manufacturing facilities and at plant sites. Those who are using PA technology have recorded significant cost savings in all

facets of construction, but even more so in reduction of downtime during outages of boilers, furnaces, and other projects involving small bore piping in close proximity to other pipes and obstructions.

Inspection service providers have reported that more than 120 welds of 3 pipe butt welds can be scanned in one eight-hour shift. Scanning can occur very soon after welding when the metal is sufficiently cool. Additionally,

testing of small bore pipe welds using ultrasonic testing instruments and manually driven, semi-automated scanners do not require A/C power. This adds a tremendous complement to safety.

COdes

One major issue facing automatic ultrasonic testing (AUT) is code acceptance, but that improved significantly in July 2010, when ASME

published three Mandatory Appendices on AUT (4) and two on phased arrays (5). The three Mandatory Appendices on AUT should allow operators to inspect welded components using AUT with more clearly defined inspection criteria.

In addition, ASME recently published a Code Case on calibration for pipes (6), which permits much greater flexibility

in pipe diameter (0.9 to 1.5 times the

nominal) and in wall thickness (+ 25%), in keeping with other global codes. The

three AUT Mandatory Appendices effectively replace Code Case 2235(7).

The two Mandatory Appendices on phased arrays cover both manual and encoded scanning. The Mandatory Appendix for encoded scanning requires fully automated or semi-automated scans, with appropriate data recording, displays, reporting, and scanning conditions. Section V, Article 4, can be called upon by any number of ASME referencing codes, which includes Sections I, VIII, and XII. In addition, other non-pressure

vessel codes can call for ultrasonics and use these set-up rules, e.g., ASME B31.1 and B31.3.

equIpmeNT

Industry demand for off-the-shelf equipment to provide complete application solutions for small-diameter pipes has driven manufacturers to design and produce small scanners (see Figures 1 and 2). These scanners are semi-automated (encoded and hand-pushed around the weld).

Figure 1: Small, hand-held scanner in action.


FEaturEBuLLEtiN

Hand-propelling saves costs, is technically easier, and provides ultra-lowprofile design, which makes

scanning between tubes convenient. The scanner itself can be adapted to a range of sizes matched to the pipe diameter. As it is spring-loaded, it can inspect both carbon steel and non-magnetic materials (e.g., stainless steels). Field experience has shown that the scanner provides good coupling for 360o around the pipe, which is essential.

These lowprofile scanners can

inspect pipe diameters from 21 mm (0.84) OD to 115 mm (4.5) OD.

Clearance, including the lowprofile

array, is only 12 mm, which permits it to inspect most small-diameter welds in most configurations. It is waterproof,

rust-free, and CE compliant. Scanners can be configured to inspect both sides

of unobstructed circumferential welds. (See Figure 2.)

Figure 2: Two-sided scan being performed on small-diameter vertical pipe.

Figure 3: Phased array probes and scanner positioned to scan a weld with single-sided access.

For welds with one-sided access only (flanges or pipestocomponent),

the scanner can be reconfigured for

single access. (See Figure 3.)

WeLd quALITy ReVIeW ON The fLy

In an effort to streamline weld inspection, the latest portable ultrasonic instruments are capable of viewing images of a weld using S-scans (side or swept angle scans) and C-scan (plan) views simultaneously. Such features allow inspectors to determine go/no-go very quickly; therefore, production of welds is not impacted due to inspection. In many cases, anomalies produced due to welding procedures are identified


Data display with S-scan and C-scan (side and plain views).

and corrected very early, which helps reduce the quantity of repairs and lost production.

Another major advantage of using PA is that there is no disruption to the production schedule. PA is safe, so no clearing or local shutdowns are required to minimize safety issues.

Multigroup scanning (scanning up to eight channels of data at the same time), is yet another time-saving feature of PA. Multigroup effects are where two separate images are shown, one from each side of the weld. These images consist of two A-scans (waveforms), S-scans, and C-scans. The A-scans show the time-corrected gain (TCG) and angle-corrected gain (ACG) data, such that all points above the recording threshold at any scanning angle show the same color/palette. This is very convenient for analyzing results quickly. Devices such as Olympus' NDT portable PA instrument OmniScan have linked cursors, so any item selected by a cursor in one image will link to other images automatically.

meAsuRING defeCT LeNGTh

Measuring weld defect length is generally straightforward, as signal amplitude drops of 50% are usually

selected. This follows the basic concept that defects are generally smooth and flat, although this is not always the case.

meAsuRING defeCT depTh

Measuring weld defect depth on thin-walled pipes is not always required by code. This type of inspection is usually more challenging, but also more critical for ensuring

structural integrity. The traditional method of amplitude drop-off gives a reasonable estimate of defect depth.

Zooming the image and recording the depth will give better defect sizing and more precise defect location. Both can be recorded in the defect tables. Sizing defects can also be based on diffraction rather than amplitude.

CONCLusIONs

Instruments, software, and scanners are available off-the-shelf for performing standard PA weld inspections on small-diameter pipes. Phased arrays can be performed manually or by using automated scanners. Codes are published and available for PA and TOFD if required. Interpreting the results can be challenging, but there is potential for better defect detection and accurate sizing because of this new technology for weld inspection.

References1. Olympus NDT, Introduction to Phased Array

Technology Applications, by R/D Tech, 2004.2. Olympus NDT, Phased Array Testing: Basic Theory

for Industrial Applications, November 2010.3. ASME Section V, Article 4, Mandatory Appendix

III, Time-of-Flight Diffraction (TOFD) Technique, 2004.

4. ASME Boiler & Pressure Vessel Code, Section V, Article 4, Mandatory Appendices VI-VIII.

5. ASME Boiler & Pressure Vessel Code, Section V, Article 4, Mandatory Appendices IV-V.

6. ASME Code Case 2638, Alternative Piping Calibration Blocks: Section V, January 20, 2010.

7. ASME Code Case 22359, Use of Ultrasonic Examination in Lieu of Radiography. Section I; Section VIII, Divisions 1 and 2; and Section XII, October 11, 2005.

Additional References 1. ASME Section V, Article 4, NonMandatory

Appendices N and O, Time of Flight Diffraction (TOFD) Interpretation and Time-of-Flight Diffraction (TOFD) Technique: General Examination Configurations.

2. F. Jacques, F. Moreau and E. Ginzel, Ultrasonic Backscatter Sizing Using Phased Array Developments in Tip Diffraction Flaw Sizing, Insight, Vol. 45, No. 11, November 2003, p. 724.

3. J. Mark Davis and M. Moles, Resolving Capabilities of Phased Array Sectorial Scans (S-Scans) on Diffracted Tip Signals, Insight, Vol. 48, No. 4, April 2006, p. 1.


Brilliantly displayed across the back walls of the restaurant is an eclectic collection of antique gages. The polished, stately instruments, many 100 years old or older, offer patrons a rare visual treat, but are also reminders of past technology before the digital age when shiny faces of gages once warned engineers and technicians if pressure was reaching dangerous levels. The collection belongs to the patriarch of

the family-owned restaurant, Frank Colleli, who is by far the most unique attraction in the establishment. If you ask him about his gages, he will likely take you by the sleeve and lead you into the hallway outside the kitchen where gages line the walls. Hell tell you a little something about each gage while busy wait staff maneuver around him balancing trays of spaghetti and lasagna.

GAuGING The pAsT

Frank was a boy when he encountered his first steam gage. His father was a locomotive

engineer and he recalls climbing up into the locomotive cab and watching his father work and check the gages.

As a young merchant marine, Frank was stationed in New Orleans. When he wasnt on the ship, he worked at an antique shop on Bourbon Street. There he learned how to clean old and tarnished relics a skill he has since mastered, as evidenced by his burnished collection.

He later obtained a stationary engineer and boiler operators license. Everything was run on gages. I was always looking at gages; had to check them every day, he remembers. They dont make them like this anymore.

Step into Villa Nova Italian restaurant in Columbus, Ohio, and your senses come alive from the savory aroma of pizza and pasta wafting from the kitchen, to the lively banter of loyal patrons gathered around tables. But there are a few more reasons around 300 of them why Villa Nova appeals to the senses.

A Collection for the

GAGes

PHOTOS BY GREG SAILOR

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hOW IT ALL BeGAN

When Frank does something, he does it 200%, says Donna, Franks wife

of 30 years. It drives me crazy, but I do enjoy it. And thats a good thing, because it was Donna who unwittingly started Franks collecting.

I ordered a few antique copper tea kettles on Ebay then told Frank Id like to have a few more, she says. Those few more accumulated to over 350 copper

tea kettles and 300 gages. The couples tea kettle collection is also on display in the restaurant and includes the worlds smallest tea kettle, which was made from a single penny and featured on PBS popular Antiques Roadshow in 2009. They also have an extensive collection of license plates. If Frank had not discovered Ebay, we wouldnt have half of this collection, Donna says.

The first gages Frank bought were

two 14 steam gages the seller claimed came from a paddle boat. They were placed over the entrance to the kitchen, where they remain, and his collection has grown from there. All types of gages are on display: steam, water temperature,

air-water, pressure, altitude, locomotive, tank pressure, and compound gages. Some come from Great Britain and Japan.

hANdIWORk

Ninety percent of Franks gages are in working condition many due to his meticulous cleaning and repair work. I strip apart every gage; each and every screw. I take it all apart. Then I polish up all the pieces and put them back together.

On average it takes Frank two hours to thoroughly clean a single gage. If one has a hand missing, no problem: Frank cuts a fitting from metal Venetian

blinds and affixes it to the instrument.

He has six workshops at home where he painstakingly restores rusted, dull gages into bright pieces of art.

I like to take things that are screwy and make them nice, Frank says, glancing around at his treasures. I look for old and different gages.

He also restores each copper kettle. Once a customer asked Frank if he dipped his kettles to get them shining. His swift reply: You dont know the half of it!

See that kettle over there, he says, pointing to a giant, cauldron-like kettle, it took me three days to clean that cockroach! The kettle was completely black and tarnished when he got it. Today, it is shiny copper, in like-new condition. A sign next to it says, The worlds largest copper tea kettle.

None of my gages or kettles will tarnish, he explains. After going through several steps to restore the items to the best condition possible (often involving steel wool, acid, and a sander), Frank adds 2-3 coats of polyurethane.

The result? Preservation of 19th and early 20th century safety instruments rarely seen on equipment today.

hAppy eNdINGs ANd BeGINNINGs

In 1986 the Collelis sold Villa Nova and moved to Florida for retirement. Twelve years later, in 1998, they were wooed back to central Ohio by their son, John (who

now runs the restaurant), to repossess the business. And thats just what Frank and Donna did.

Franks not good at retirement, Donna explains. Her husband, surrounded by customers who make it a point to greet him as they come and go, grins and nods at his wifes surmise.

Its not too surprising. When asked his philosophy on life, the 83-year-old quickly replies, Keep going. Keep moving. Never sit in the cabbage.

Frank Colleli

Franks gage collection is the featured backdrop of Executive Director David Douins picture in the Executive Message.

They dont make them like this anymore.


FEaturEBuLLEtiN

hen writing my book Inviting Disaster, I devoted an entire

chapter to the subject, ironically titled, Doubtless: Testing is Such a Bother. There youll find a rogues gallery of

insufficiently tested products such as

the US Navys Mark 14 torpedo and its Mark 6 magnetic exploder, a weapon that went off to the WWII Pacific theater

with three major design defects that took almost two years to fix before submarine

commanders could rely on it for war patrols. I also profiled Boeings 767, which

went into service with a hazardous glitch in its thrust-reverser interlocks. (Thrust reversers are the scoops that swing out from jet engines after a jet has touched down and needs to slow on the runway.) The Federal Aviation Administration permitted Boeing to do abbreviated testing on the risks of reverser deployment in flight, so the real danger wasnt detected

until the accidental deployment of the reversers on an airliner over Thailand in 1991. That crash killed everyone on board. And failure-to-test scandals continue apace, from cars to drugs to computers.

But there are plenty of testing hall-of-famers who show that even the toughest problems will give way to rigorous testing. Every road trip you take benefits from an

experimental blitz that began in 1958, which

still stands as the most comprehensive highway test ever undertaken. The US Army Corps of Engineers worked with the American Association of State Highway Officials to try out a huge variety of

highway bridges in Illinois, in preparation for building the nations interstate highway system. (Remnants of the road test can be seen today, just off I-80 near Ottawa,

Illinois.) Heavy trucks operated by Army recruits were driven around five loops of

pavement and bridges, plus a sixth loop as a control. Operations went on night and day, employing more than a hundred trucks. Some bridges failed early, but other types held up so well that the organizers had to run super-heavy loads across the spans to hasten their destruction as the two-year test drew to a close. In just 14 lane miles, the arrangement offered more than 800 combinations of pavement and foundations.

As chief of the Navys electrical section, Captain Hyman Rickover would bang electrical gear against a radiator, or even throw it out a window, to remind visiting factory reps that everything aboard a submarine had to be designed for extreme shocks from depth charges. A test pilot with Douglas Aircraft checked the toughness of its DC-8 airliner in 1961 by putting it into a supersonic dive over Edwards Air Force Base.

Dramatic stuff. While testing generates its share of exciting anecdotes, lab rats know the real point of tough

testing is to ensure daily use will be boringly serene. Passengers and other customers dont want the kind of scenes Readers Digest calls Drama in Real Life.

TesTING WhATs NOT TO LOVe?

I understand if readers of the BULLETIN regard this issues theme as so much preaching to the preachers. Certification testing on ASME code

pressure products is not just a good idea, its a requirement, says Tom Beirne, National Board senior staff engineer. If you are putting a stamp on a valve, you must have it tested. And every six years the certification needs renewal. But a

great many valves and tanks are outside the domain of government-backed safety codes (see Non-ASME Pressure Vessels at Risk, in the winter 2011 BULLETIN, on the risks of concrete trucks pressurized water tanks).

Further, even this long-regulated field doesnt sit still. Are you watching

out for risks emerging from the rapid pace of change? Brandan Ashbrook, National Board lab manager, points out that some long-time valve manufacturers are feeling competitive pressure to expand their product line to cover a much broader range of machinery and processing environments. Informational testing prior to the certification process can help

indicate when a company needs to build up some specialized expertise first.

Some manufacturers and assemblers also request informational tests from the National Board laboratory when pondering a change in key component suppliers, to verify there wont also be a change in a valves relief rating during

W

Testing... What's Not to Love?A tough world needs tough testsBy James R. Chiles


TeChNO-COmmANdmeNTs

I was touring a naval museum in Buffalo, New York, recently and a placard reminded me that the Navy has long taught its submariners the Ten Commandments of Damage Control, such as Know Your Way Around, Even in the Dark, and Keep Cool: Dont Give Up the Ship!

Seasoned safety professionals, forensic experts, and product testers could no doubt chisel out their own tablets of techno-commandments related to testing. How about this one: Thou Shalt Not Ignore the Annoying Anomaly. One of multiple root causes behind the Deepwater Horizon blowout and explosion was a botched well test as an inexperienced Transocean drilling crew finished work on

a cement plug at the Macondo well, before delatching the rig. While the drilling crew knew that a negative pressure test after cementing hadnt returned the expected results, they found other tests reassuring. Not knowing the inherent danger of the situation or how several onthefly

procedures had increased the danger of a blowout, they set aside the anomaly as unimportant. Yielding to BPs subtle pressure to finish the abandonment job

sooner rather than later, they didnt pause to check with seasoned experts some of whom were coincidentally aboard the rig in a group of Transocean VIPs, present to hand out safety awards, of all things.

Heres another for the stone tablet: Thou Shalt Not Regard a Half-Test as a

Full Test. This refers to a very common sin of omission. One example of the full test comes from the field of new, high

tech buildings: an exhaustive, day-long procedure called the Whole-Building Shutdown. With many witnesses in place and data recorders running, the tester throws a switch that cuts the building off from the grid, simulating an area power failure. Observers at strategic locations

its sixyear certification period. As an

example, explains Beirne, a manufacturer might have purchasing people who can get a better price on springs. The spring is an important part of a valve. Say the new source is from overseas. It isnt the 40-year supplier the manufacturer is used to. If the metal is different, perhaps in how it was heat treated, there will be a different spring rate.

Whats in the future? Perhaps new types of tests for makers of industrial valves not currently covered by ASME codes (for example, choke valves at a refinery, which are now under American

Petroleum Institute guidelines), who want to verify that their models wont fail due to damage in long service, such as from stress-corrosion cracking. Many products that looked peachy under lab conditions later failed due to chemicals common to todays environment, such as engine-compartment fuel lines that leaked due to ozone damage and caused deadly fires.

One of the biggest class-action lawsuits in history arose out of leaky plastic pipes and fittings. That cracking was due to oxidation

caused by chlorine a common sanitizing agent in domestic water supplies. Another element metallurgists know to watch out for is hydrogen, which turns some grades of steel brittle over time. Without special care and advance testing, hydrogen embrittlement could be an obstacle to widespread use of hydrogen in vehicles.

Another assault on valves can come from vibrations, such as resonant chatter. Energy may be transmitted into the valve via the steel of long piping runs, or as pressure waves traveling down a pipes liquid contents. Ashbrook says that chemical processing plants have reported occasional catastrophic failures of large control valves. At its worst, a spindle with its hand-wheel can entirely blast off of a valve body, spewing flammable vapors

into the middle of a refinery complex.

check whether all critical components shut down, switched over, and started per specifications. (Such as: did ventilation

louvers to gensets in the penthouse open as they were supposed to? If not, the engines will overheat.) Often such a test identifies

some fixes for the punch list. As hundreds

of building owners discovered during the 2003 Northeast Blackout, having an emergency generator and UPS battery bank on site is not the same as having them work.

One final word about complex systems

tested in place. Even the enthusiastically pro-testing person can think of examples where a test went seriously wrong due to flawed planning or somebodys failure

to complete a checklist. In particular, take extra care when testing single-point-failure machines in the field. Watch out

for what seasoned testers call the second-order consequence the unanticipated side-effect. Compared to quality tests at the factory, where equipment is new and tested in isolation, inservice tests can spring second-order surprises any time from setup all the way through to restoring all normal connections.

While earthly geographic frontiers dont last for long, complex machines get more complicated and spring new surprises. Good testing helps map safe routes through the machine frontier. Its not just good citizenship; its good business.

James R. Chiles, author of Inviting Disaster and The God Machine has been writing about technology and history for

over 30 years. He has appeared multiple

times on the History Channel and has written

for Smithsonian, Air & Space, Popular Science, The Boston Globe, Aviation Weekly, Mechanical Engineering, and Invention & Technology. He maintains a blog called Disaster-Wise and can be reached at [email protected].

Boiler External Piping (BEP)part 2 Feedwater pipingBy Steve Kalmbach

FEaturEBuLLEtiN


16

Feedwater piping for steam boilers is composed of various different configurations to meet boiler plant re-quirements. There are differences between a single-boiler installation with a simple on and off feedwater pump ar-rangement and complex feedwater systems for multiple boilers with feedwater economizers. Each of these differ-ing systems has distinct ASME Power Piping B31.1 termina-tion points for ASME Boiler and Pressure Vessel Code, Section I, code-required piping limits. This article will look at the various requirements for feedwater systems.

Unlike the welldefined ASME Section I and ASME

B31.1 requirements for steam and blowoff piping, the ter-mination points for feedwater piping are determined by the arrangements used for supplying feedwater to the boiler. These rules are found in ASME Section I, Figure PG-58.3.1(a), paragraphs PG59.3.3 through PG58.3.5; PG61;

and ASME B31.1, Figure 100.1.2(B), paragraphs 122.1.3 and 122.1.7(B.1). The following basic rules will apply for all feedwater systems discussed in this article.

desIGN RequIRemeNTs

Design requirements for all feedwater piping classi-fied as BEP are as follows:

Design pressure: the maximum allowable work-ing pressure (MAWP) plus 25% or MAWP plus 225

pounds per square inch (psi), whichever is lower, plus the applicable static head (rule 101.2.2).

The transition pressure at which one switches from adding 25% of the MAWP to adding 225 psi occurs at

the 900 psi level, plus the applicable static head. If the design pressure is less than or equal to 900 psi,

add 25% plus the applicable static head. If the design

pressure is greater than 900 psi, add 225 psi, plus the

applicable static head.

The design temperature is based on the saturation temperature of steam at the MAWP of the boiler. Note that

this design pressure is based on the MAWP and not the pressure-relieving device setting or operating pressure.

There are additional design rules that apply to all types of boiler feedwater piping. The code requires the installa-tion of a stop valve located at the boiler feedwater connec-tion. Piping from the stop valve to the boiler feedwater connection shall be the same size as the boiler feedwater connection. From this stop valve to the BEP termination point, piping may be reduced to the size required to supply the boiler with feedwater.

Feedwater piping not part of BEP is classified as non

boiler external piping (NBEP). The ASME Section I code requires this piping be able to supply the required amount of feedwater to the boiler when the highest set pressure- relieving device, plus 3%, is operating. Unlike the pressure

requirements for BEP, this rule may allow the use of pipe fittings of a different class than the BEP design requirement

if the pressure-relieving devices installed are less than the MAWP of the boiler.

The ASME B31.1 code specifically states the required

stop valve shall be the first valve off the boiler with the

check valve located upstream. The only exception to this rule is in ASME B31.1, paragraph 122.1.7 (B2), for feedwa-ter piping used on a single boiler turbine unit system where the check valve may be the first valve off of the boiler with

the stop valve located upstream. It is permissible to have a different size check valve and stop valve.

Lets start our discussion about feedwater piping with a very basic feedwater system found on the majority of small-to-medium-sized boilers: the on-off feedwater system.

BAsIC ON-Off feedWATeR sysTems

Basic feedwater systems for small and moderately sized boilers utilize a boiler-mounted level control which energizes the feedwater pump when the boiler water level reaches a low point and then will stop the feedwater pump when the normal operating water level is reached. This

This is the second in a three-part series on steam, feedwater, and blowoff piping. Previous articles in this series on boiler external piping (BEP) appeared in the winter (introduction) and summer (part 1, steam piping) 2012 issues.


arrangement requires the minimum of a stop valve located at the boiler and a check valve installed before or upstream of this valve. The stop valve and its piping connecting to the boiler feedwater connection shall be the same size as the boiler connection. The remaining piping in the BEP lim-its may, however, be reduced to the size required to supply the boiler, if needed. The design pressure for piping from the termination point to the feedwater source is subject to ASME Section I, which requires this piping to be able to sup-ply the required amount of feedwater to the boiler when the highest set pressurerelieving device, plus 3%, is operating.

In the case where these pressure-relieving devices are lower than the boiler MAWP, it may allow the use of fittings with

a lower class rating than for the piping used within BEP

limits. Caution should be used if pressure-relieving devices are changed to the MAWP rating of the boiler to ensure fit-tings are suitable for use at the new pressure requirement.

feedWATeR-ReGuLATING CONTROL VALVes

The next arrangement gaining in popularity is the use of a feedwater-regulating valve controlled by variation in the boiler water level. This type of system provides better and more consistent boiler water level control, and is becoming standard as larger firetube boilers are being installed.

Boiler feed water connection

Example of one pump supplying two or more boilers utilizing a three-valve bypass around the regulator valve.

FEaturEBuLLEtiN


the economizer inlet connection. The economizer pressure-relieving requirements are now met by the boiler pressure-relieving valves and additional protection is not required for the economizer.

A problem will arise when code-required feedwater piping and valves are located between the economizer out-let connection and the boiler feedwater inlet connection. The economizer can now be isolated from the boiler and become a fired pressure vessel requiring pressurerelieving

valves. This piping now must meet the ASME B31.1 code rules for BEP piping.

The BEP design rules are now defined by the MAWP

of the economizer, or the shutoff pressure of the feedwater system pump, not by the boiler MAWP. It is permissible to install pressure-relieving devices on the economizer based on the MAWP of the economizer, even if it exceeds the boiler MAWP. To guarantee feedwater flow to the boiler,

these valves should be carefully selected so that the boiler pressure-relieving valves operate before the economizer pressure-relieving devices. Since the economizer MAWP is generally much higher than the boilers MAWP, there is the possibility that the BEP will be exposed to this higher pressure. It is possible for a boiler with a MAWP of 150

psi and with feedwater piping designed for 188 psi that incorporates an economizer designed for a MAWP of 400 psi, with pressure-relieving devices with a setting of 400 psi, now subjecting this 188 psi piping to 400 psi. An econo-mizer located upstream (pump side) of the required BEP boundaries will require a design pressure compatible with the feedwater pressure at the location installed. This will normally be considerably higher than any of the design pressures employed within the scope of the BEP.

feedWATeR pumps

When an inspection is performed on a boiler and it is noted that the operating pressure is substantially lower than the pressure-relieving valve setting, the feedwater pump should be checked to ensure it meets the require-ments of ASME Section I, which says feedwater pumps should be able to supply the required amount of feedwater to the boiler when the highest set pressure-relieving device, plus 3%, is operating. If the pressurerelieving devices are

set for 150 psi and the boiler is operating at 60 psi, there is

This system is also used for multiple boiler installations where there is a common feedwater header with multiple feedwater pumps. ASME Section I code compliance requires that the feedwater system be able to supply the required amount of feedwater to the boiler when the highest set pressurerelieving device, plus 3%, is operating. Good

engineering practice requires feedwater valves and piping meet this requirement for safe boiler operation. Caution should be used if pressure-relieving devices are installed using a setting less than the MAWP, and then changed at a future date to the MAWP of the boiler. Feedwater pumps and valves should be checked and confirmed that they are still in code compliance if changes are made.

When using a feedwater valve, close examination of the feedwater arrangement should be performed to deter-mine BEP termination points. As noted earlier, the required check valve and stop valve are also included in this piping. When a feedwater valve is installed without a bypass, it becomes the termination point and is subject to the design rules for feedwater piping. As for the basic feedwater sys-tems mentioned earlier, this feedwater valve and piping to the required stop valve may be reduced in size to what is required to feed the boiler. When a feedwater regulator valve is equipped with a three-valve bypass, the BEP ter-mination points are relocated. The new locations will be the outboard face of the block and bypass valves (see Fig-ure 100.1.2(B) of ASME B31.1). In this case the feedwater valve is only subject to the design requirement of 3% over

the highest set pressure-relieving device. All valves and the feedwater control valve must be sized to provide the required amount of feedwater to be code compliant.

feedWATeR eCONOmIzeRs

Another installation becoming more common is the use of a feedwater economizer that is mounted in the boiler stack. Installing these systems can present problems in de-fining the termination points and other requirements for

compliance with ASME B31.1. ASME Section I states spe-cifically that if an economizer is installed without any inter-vening valves between the economizer outlet connection and the boiler feedwater connection, it is the responsibility of the ASME Section I code committee. The required valves for BEP compliance only apply to the piping installed on

12


This system is also used for multiple boiler installations where there is a common feedwater header with multiple feedwater pumps. ASME Section I code compliance requires that the feedwater system be able to supply the required amount of feedwater to the boiler when the highest set pressurerelieving device, plus 3%, is operating. Good

engineering practice requires feedwater valves and piping meet this requirement for safe boiler operation. Caution should be used if pressure-relieving devices are installed using a setting less than the MAWP, and then changed at a future date to the MAWP of the boiler. Feedwater pumps and valves should be checked and confirmed that they are still in code compliance if changes are made.

When using a feedwater valve, close examination of the feedwater arrangement should be performed to deter-mine BEP termination points. As noted earlier, the required check valve and stop valve are also included in this piping. When a feedwater valve is installed without a bypass, it becomes the termination point and is subject to the design rules for feedwater piping. As for the basic feedwater sys-tems mentioned earlier, this feedwater valve and piping to the required stop valve may be reduced in size to what is required to feed the boiler. When a feedwater regulator valve is equipped with a three-valve bypass, the BEP ter-mination points are relocated. The new locations will be the outboard face of the block and bypass valves (see Fig-ure 100.1.2(B) of ASME B31.1). In this case the feedwater valve is only subject to the design requirement of 3% over

the highest set pressure-relieving device. All valves and the feedwater control valve must be sized to provide the required amount of feedwater to be code compliant.

feedWATeR eCONOmIzeRs

Another installation becoming more common is the use of a feedwater economizer that is mounted in the boiler stack. Installing these systems can present problems in de-fining the termination points and other requirements for

compliance with ASME B31.1. ASME Section I states spe-cifically that if an economizer is installed without any inter-vening valves between the economizer outlet connection and the boiler feedwater connection, it is the responsibility of the ASME Section I code committee. The required valves for BEP compliance only apply to the piping installed on

12

a possibility the feedwater pump is not sized properly. For the pump to stay within the performance curve at 60 psi, it is doubtful the pump can supply the required feedwater at 150 psi plus 3%; however, if a pump is installed that is

sized for 150 psi plus 3%, it will probably be off the perfor-mance curve at 60 psi. Pump flow is inversely related to

the output pressure. As pressure increases, flow decreases.

When the operating pressure and the pressure-relieving set pressures are closer together, the pump will probably per-form properly. It is still wise to confirm the pump meets the

requirements and is in compliance with the ASME Section I code.

pRessuRe-ReLIeVING deVICes

Sometimes it may become necessary to lower the set pressure of pressure-relieving devices so the feedwater pump is within design and operating parameters and in conformance with ASME Section I code rules. This is per-missible within code requirements as long as the required pressure-relieving capacity is provided. As the set pressure of the pressure-relieving device is lowered, the device will become larger to provide the required capacity. There may be a limitation as to how much the pressure may be low-ered, as the size of the pressure-relieving devices will be limited by the size of the openings in the boiler.

IN CONCLusION

The installation and inspection of feedwater piping subject to ASME Section I and ASME B31.1 rules for BEP requires a detailed examination of each system to ensure code compliance. Each feedwater system is unique and will have to meet specific requirements to be in code com-pliance. This examination will determine the BEP termina-tion points and the items subject to these rules. The follow-ing items should be checked to ensure code compliance:

The code requires at minimum a stop valve located at the boiler feedwater connection and a check valve in-stalled upstream of this valve.

The stop valve and piping to the boiler feedwater con-nection shall be the same size as the boiler feedwater connection.

The design pressure for feedwater piping subject to BEP requirements is MAWP plus 25% or MAWP plus

225 psi, whichever is lower. NOTE: This is based on

the MAWP, not the operating or pressure-relieving device pressure setting.

The design temperature for this piping is based on the saturation steam temperature at the MAWP of the boiler.

When a feedwater level control valve is installed without a bypass, the valve itself becomes the BEP termination point.

When a feedwater level control valve is installed with isolation valves and a bypass, the bypass and the iso-lation valve (located downstream of the feedwater control valve) become the BEP termination point.

When using an economizer without any intervening valves between the economizer and the boiler feed-water connection, BEP rules apply to the inlet of the economizer and pressure-relieving valves are not re-quired on the economizer.

Use caution when installing feedwater level control valves between the economizer outlet connection and the boiler feedwater inlet connection. This piping now may be subject to the economizer MAWP, not the boil-er MAWP. Pressure-relieving valves are now required on the economizer.

The feedwater source must be capable of supplying the required amount of feedwater to the boiler at 3%

over the highest set pressure-relieving device.

Part 3 in this series will discuss the correct and code-compliant installation and inspection of an often over-looked and improperly installed boiler piping system blowoff valves and piping.

Steve Kalmbach has been involved in the boiler repair,

maintenance, and service industry for 30 years. His company,

Kasco, has a National Board R Certificate of Authorization for repairs and alterations and an ASME Certificate of

Authorization with S and U designators controlled by the office in Golden, Colorado. He can be reached at skalmb4427@

aol.com.


Implementing the New ASME Code StampChallenges for pressure Relief DevicesBy JoSEPH f. BALL, P.E., DiRECToR, PRESSuRE RELiEf DEPARTMEnT

The ASME Boiler and Pressure

Vessel Code 2011 addenda included a new, single ASME certification mark

that will replace all 25 Code Symbol Stamps included in the

ASME Boiler and Pressure Vessel Code, as well as stamps and marks used for other ASME programs and equipment outside of the boiler code.

Implementation of the new mark was necessitated by ASMEs need to protect its symbols in countries all over the world, which includes the costly legal registration of trademarked symbols wherever they could be used. Because ASME has a large number of symbols, and is continuously expanding the locations where ASME-stamped equipment might be supplied, maintaining control over them had become more and more burdensome. Therefore, the new single mark was developed to protect the trademark in the future.

The certification mark consists of the

letters ASME positioned diagonally inside the traditional cloverleaf symbol, and must be accompanied by one or more letters, called the designator. The designator describes the object in more detail and consists of the letters previously used with the old Code Symbol Stamp. The designator is descriptive of the device being marked, but is not actually part of the mark itself. A method for applying the designator is not included with the new ASME stamp, so it will be applied separately using the

PrEssurE rELiEF rEPortDEPartMENt

same method as for any other nameplate markings or stampings.

XX(XX = designator)

Because this is a significant change,

ASME Certificate Holders were provided

an extra year to administer the new mark. This new stamp and designator must be implemented by the end of 2012. Extra time was formalized by Code Cases 2710 and 2714.

For most code stamp holders addition of the new mark is relatively straightforward. To apply the new mark, ASME is in the process of providing stamps to certificateholding

organizations. Certificate holders will

need to plan for a space on their nameplate for the designator.

Applying the new mark on pressure relief devices (PRDs) can be challenging. Space on pressure relief device nameplates has always been at a premium. The code has long made an exception for the minimum size of letters and numbers for pressure relief device markings, and a common complaint by inspectors is that the PRD markings are hard to read. The new ASME stamp is by (12.7 mm x 12.7 mm) which is larger than the previous pressure relief device code stamp. (Another version, x , is also available.) With the larger stamp, plus the new designator, addition of the mark has become very difficult due to

space restrictions.On larger pressure relief valves

there is room for bigger nameplates, so some organizations are enlarging their nameplates to make room for the new mark and designator; however, this is not an option on smaller devices. For smaller valves, organizations have used an alternate marking method for applying the current code stamp.

Fortunately, there is an acceptance procedure available to organizations who want an alternative to the new steel stamp issued by ASME. Alternative methods of applying the stamp must be accepted by ASME, which will be done


manufacturers and assemblers should be well into the planning process for how they will implement the new mark. The remaining time this year should include plans to use up existing nameplate stock while the current code stamp can still be used to minimize the effect on inventory when new nameplates are needed. This may be an opportunity to upgrade and modernize marking methods, allowing for increased efficiency and improved

accuracy in the process.For acceptance of an alternative

marking method, please provide the following information:

upon recommendation from the National Board, the ASME-designated organization for pressure relief devices.

For the alternative method to be considered, it must meet the following criteria:

1. The mark must be an acceptable facsimile of the ASME mark.

2. The size of the mark is not specified, but it must be legible and permanent. The mark will most likely be smaller than the steel stamp issued by ASME.

3. The procedure for controlling the use of the alternative stamping method must be documented and addressed in the organizations quality program.

Alternative methods that have been used include: roll stamping with a die, laser marking, photosensitive etching, and metal pin scribing or metal dot matrix printing. These marking methods can be automated and allow all required nameplate information to be applied at the same time. These processes are often integrated into a companys business system, allowing information stored in computer files to be directly applied to

the nameplate (such as model number, set pressure, capacity, serial number, etc.).

The alternative marking method can be seen as an improvement over using a hammer to strike a metal stamp onto a PRD, as PRDs can be considered precision instruments that should be handled with extreme care until they are installed.

The implementation deadline, 2013, will be here before we know it. PRD

1. A drawing or other method of documenting the arrangement of the new stamping. In some cases this may be a CAD or drafting file identification.

The drawing or file must be approved and controlled by the Certificate

Holders quality system.

2. A sample of the actual stamping method on a nameplate, tag, valve body, or rupture disk holder shall be supplied. A large detailed picture can be used for this purpose.

3. A copy of the procedure for controlling use of the stamp.

WATER TEST SYSTEM

pRd designators for pressure Relief devicesDesignator Service V Section I pressure relief valves for boilers NV Section III pressure relief valves for nuclear equipment hV Section IV pressure relief valves for heating boilers and hot water heaters uV Section VIII pressure relief valves for unfired pressure vessels ud Section VIII pressure relief devices for unfired pressure vessels (usually rupture disks) TV Section XII pressure relief valves for transport tanks Td Section XII pressure relief devices for transport tanks

This information can be sent to the Pressure Relief Department at:

National Board pressure Relief department 7437 pingue drive Worthington, Oh 43085

E-mail to: [email protected]

After the information is reviewed and accepted, the National Board will forward a recommendation to ASME that the alternative marking method be accepted. ASME should then provide an acceptance letter before the time when implementation is required.

covEr storYBuLLEtiN


Testing...

Testing...1, 2, 3...Expansion Project Complete, Its Full Speed Ahead at the National Board Testing Lab


Bulletin photographs by Brandon Sofsky

2012 is a landmark

year for the National

Board Testing

Laboratory (NBTL).

It marks the 75th

anniversary of its

existence (in multiple

locations) and a year

of substantial growth

and change.

Testing...1, 2, 3...Expansion Project Complete, Its Full Speed Ahead at the National Board Testing Lab

NATIONAL BOARD

covEr storYBuLLEtiN


he National Board Testing Lab is an independent ASMEcertified flow lab

where staff conducts tests on pressure-relieving devices from valve manufacturers, assemblers, and repair facilities around the globe. Currently, the lab performs over 180 tests a month and hosts approximately 300 people representing 130 companies and 20 countries each year. Nearly half of all tests are witnessed by the customers.

To accommodate a record number of tests in recent years, the lab has undergone a major expansion of its facilities. What started as a need for additional storage morphed into a nearly 3,000 square foot addition to the southeast side of the building.

But it didnt stop there.

With the support and foresight of National Board senior management and the Board of Trustees, staff also looked at ways they could improve the existing test systems and equipment. "National Board leadership recognizes the importance of investing in the future of pressure relief testing. The expansion project is our commitment to safe, efficient, and accurate

testing now and for years to come," says Executive Director David Douin.

In light of newer technologies and different methods of recording and measuring data, significant upgrades were made

on the existing air and steam test systems. Digital automation was installed on every steam, air, and water testing console to electronically capture and record test results in the most accurate and efficient means possible. An entirely new air

test line was added and a new maintenance area built. Air

compressors were replaced with a liquid nitrogen storage and vaporizing system. And theres been an overall increase in flow

and pressure capacity.All of this is to the clients advantage. Its a win-win

situation, says National Board Lab Manager Brandan Ashbrook. The process is quicker and there is less wait time between tests. We can test more than one customer at a time. Our new data automation system captures and records test results with greater accuracy, and international clients will be able to view recorded test data as if 'live' without traveling to the lab, which means tremendous travel cost savings for them.

NeW AIR TesTING sysTem

The extra 3,000- square-foot add-on to the lab made it possible for the installation of a brand new air testing system, which was high on the wish list to help meet the growing demand for air tests.

LEFT: The crane used to install two vaporizers.RIGHT: New nitrogen tank and both vaporizers at work.BELOW: Setting up the new air testing system inside the 3,000-square-foot addition.

T

We have the option of running three different jobs on one system: a 2,500psi line, a 1,350psi line,

and rupture disk tests.

covEr storYBuLLEtiN


main area of the national Board Testing Laboratory contains three test

systems using steam, nitrogen, and water. Each system features the following:

DATA AcquisitionA computer-based acquisition system is available to electronically capture the best data

for flow computation and analysis.

Steam Air Water

Media

MaximumSource Pressure

Flow Measurement Prime Meters

Maximum Stamped Set Pressure

Maximum Stamped Flow Capacity

Dry Saturated Steam

850 psig (58 bar)

Weighed Condensate Method

500 psi (34 bar)4" (DN 100)

16,000 pph(7,257 kg/h)

Compressed Nitrogen

3,500 psig (238 bar)

Sonic Flow Nozzle &Sharp-Edged Orifice Plate

Ambient Temp. Water

625 psi(43 bar)

Sharp-Edged Orifice Plates &

Timed Weight Method

500 psi (34 bar)4" (DN 100)

550 gpm(2,082 l/min)

Low Medium High

580 psi (39 bar) 1,100 psi (75 bar) 2,025 psi (138 bar) 6" (DN 150) 4" (DN 100) " (DN 20)

13,000 scfm 25,000 scfm 5,000 scfm(22,087 m3/h) (42,475 m3/h) (8,495 m3/h)

The new line is equipped with full air valve testing capabilities and includes a 4 line and a new test vessel with permanently installed rupture disk rigs. A blast diffuser was mounted on the far wall and the discharge end of the rupture disk rigs point at it to safely dissipate the released energy during testing.

This is going to be our everyday workhorse, says Ashbrook as he motions toward the new test line. We have the option of running three different jobs on one system: a 2,500psi

line, a 1,350psi line, and rupture disk tests.

With the addition of the air test line, the lab can theoretically run all four test lines independently, essentially doubling the number of air tests the lab can accommodate at one time.

The set-up of the original lab was such that one crew would spend all day with a customer testing one valve at a time and moving from one test location to another to another. To make matters worse, we had a problem of running out of air, says Ashbrook, noting it could turn into a long process for visiting clients because of waiting on air storage bottles to refill to flow

test valves.Now weve fixed those problems in multiple ways,

Ashbrook says. We have more air storage. We have more

output with the nitrogen system, which now makes the air. And by adding another test line, weve doubled our air testing capabilities. And since the new line was installed with permanent rupture disk rigs, set-up time is greatly reduced for rupture disk testing.

The pRessuRe fOR AIR

As mentioned, running out of air was becoming a problem as testing increased, so air supply capacity was one area the team wanted to improve.

The lab was using three air compressors to make high-pressure air supply for running tests. Two compressors produced 65 standard cubic feet per minute (scfm) each, and the other

produced 75 scfm. With all three running, they supplied 205

scfm of compressed air (volume). One of our challenges was that we needed to refill the

stored air supply quicker. There were times we would wait an hour or longer for the storage bottles to top off so we could flow

test a large capacity valve, says Ashbrook.Original plans called for adding two new 100-horsepower

(hp) air compressors. We already knew we needed more supply,


Steam Air Water

which is why we planned on adding double the storage bottles, he explains. We felt good about our plans to double the storage bottles and double our ability to make air. But what happened next was not so great.

When exploring what was needed to supply the extra electric load of the new compressors, it was determined the building would need more switch gear at the transformer to supply more power. They would also need to install an oil interceptor into the floor for the condensate run off (oily water

from running the compressors). Also, the dryer and cooler would need to be replaced with units that could bear the load of the increased air capacity.

Considering the cost of upgrading the air compressors, the team turned their attention to liquid nitrogen air supply systems. They calculated how much nitrogen they would need compared to the air compressors, and started running pros and cons. They found that the initial equipment purchase for an equivalent capacity nitrogen system was considerably less than upgrading and adding more air compressors. And unlike compressed air, the nitrogen system was free of oil and completely dry, eliminating the need for oil separation, cooling, and drying. The pros were outweighing the cons.

heRes WhAT They CAme up WITh

Running both new and older air compressors would yield 370 scfm. So what would it take in gallons of liquid nitrogen to equal this? One gallon of liquid nitrogen equals 93.11 scfm of nitrogen gas.

They divided 370 by 93.11 which equals 3.97 gallons. Knowing the conversion rate and target number, they sized a pump with a nozzle of 4.2 gallons per minute to give them an output of 391 scfm. This met and slightly exceeded their target range. So if one pump would equal four air compressors, two pumps would be better yet. We realized that if we had a failure, we could run the other pump and continue testing valves with no halt in testing and no lag time for customers, Ashbrook says. With both pumps running they make almost four times their original value.

Tom Beirne, senior staff engineer in the Pressure Relief Department, elaborates. The air compressors and

BELOW: From left to right: Lab staff David Hennon, Zach Burwell, and Brandan Ashbrook set up a rupture disk test on the new line.


nitrogen system both function the same as a supply source, but we began to see that making the switch to nitrogen would be more efficient for our testing operation. And since weve made

the switch there have been no air shortages. Its reliable. We havent had to wait for refill.

Ashbrook reinforces this point: Were using the same source compressed nitrogen is equivalent to compressed air but how were making it is more efficient. It took us about 15 minutes

to top off all 12 bottles with the nitrogen system. So with our day-to-day testing, we are never waiting on supply anymore.

Ashbrook explains that the tank, located outside the building, has its own cell phone mounted on a solar panel. Twice a day it sends a signal to the nitrogen supplier to monitor the storage vessel levels. When the nitrogen hits a low level, the system alerts the companys dispatch, which sends a truck to refill the liquid storage vessel. And the pumps that supply

the liquid to the vaporizers (and ultimately nitrogen gas to the high-pressure storage bottles) are always on standby. When the pressure dips below a certain set point, the pump kicks on and the bottles are filled.

Weve nailed our objective, Ashbrook concludes. Weve successfully increased our air capacity and quickened customer testing times.

The last air test before the switch to the nitrogen system was performed on April 3 for General Electric. It was test number 32,512A for research and development.

TesT sTATION AuTOmATION

Prior to the 2012 expansion, the process of capturing and measuring test results (data acquisition, DAQ) was semi-automated and used for rupture disk testing. With the increased volume of tests, the decision was made to fully automate DAQ capabilities and expand its usage to all test station consoles.

The automated DAQ system provides immediate test results in digital format for analysis and reporting. Visiting clients and technicians can view results and determine on the spot (while the test setup is still intact) if repeat tests are necessary. Customized, preliminary reports are printed and given to clients at the conclusion of testing, while electronic documentation is automatically forwarded to a professional engineer for approval.

Technicians can perform calculations at each station rather than manually enter results into a separate computer, and they also have access to National Board forms and applications at

By adding six new 4,000-psi storage vessels, the lab more than doubled its original storage capacity, expanded its testing range, and eliminated the delay between tests of larger capacity air valves, which also means less wait time for customers. here are some details on the system:

The nitrogen system consists of a 6,000-gallon liquid nitrogen storage tank; two, 20-hp/4,000-psi pumps; and two vaporizers used to convert nitro-gen from liquid to gas.

The two, 20-hp pumps are set up to run inde-pendently or at the same time as needed to meet demand.

The nitrogen pumps each have a

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