bolted - 2009-en-1.pdf
TRANSCRIPT
-
8/10/2019 Bolted - 2009-EN-1.pdf
1/20
SIZE MATTERSCHOOSING THE RIGHT BOLT FOR THE JOB
O R D E R F
R E E N
O R D -
S A M P L
E S
w w
w . n o
r d - l o
c k
THE ANCHOR BOLTTHAT LASTSFOR 120 YEARS
smart design
CRACKINGTHE RIDDLEOF LOOSE NUTS
grundfos pumps
MEET THE MAN
WHO MADEOIL RIGS SAFER
offshore
NORD-LOCKSECURITYSOLUTIONS4
A MAGAZINE ABOUT OPTIMISING BOLT SECURING #1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
2/20
Are you interested in minimising the time for assemblyand disassembly of bolted joints?Lower your costs for maintenance, repair and overhaul?Eliminate production stops due to bolt failure?
Nord-Lock is designed to secure fasteners in extremeconditions. Go to www.nord-lock.com/contact and
order free samples for real life testing.
www.nord-lock.comMADE IN SWEDEN
ORDER FREENORD-LOCKSAMPLES
-
8/10/2019 Bolted - 2009-EN-1.pdf
3/203BOLTED # 1 2009
bolted #1 2009
CONTENTS
About optimising bolt securing the very rst issue of Nord-Locks customer magazine
You cant losewhen nothing is loose
08 Size mattersThe complexity of a bolt security system issometimes under-estimated, and the bolts are oftenover-sized. Mistakes such as these can be avoided.
12 Grundfos pumps it upDanish pump manufacturer Grundfos had anexpensive problem with nuts coming loose. Acustomised washer pair solved it all.
16 Tunnel visionTrains in the tunnel between Sweden and Denmarkwill make everything vibrate. But a special anchor boltkeeps the gantries secured for over 120 years.
04 08 15
Bolts and nuts are the most used machineelements installed in everything fromcomputers and hospital beds to heavymachinery and nuclear plants. The obviousreason for this widely spread use, is of coursethat they offer the unbeatable combination ofgreat holding power whilst still being easy todismantle. Yet, in product development anddesign, fasteners often end up as one of the lastproblems that is examined. Courses on designand mechanical engineering also tend to focus very little on threaded fasteners. But spendinga little extra time on bolts might just pay back.Multiple times.
With almost thirty years of focus on boltsecurity, Nord-Lock has built up a know-ledge bank through our quality testing andour technical service, which include customisedtests for extreme applications. Nord-Lock has per-formed hundreds of tests for customers in a large variety of industries over the years. Every year, ourglobal team of sales engineers meet clients locallyto help optimise demanding and exposed boltedassemblies.
With this magazine we want to further share this
knowledge with you, whether you are a customer
of ours or just someone who experiences problems with vibration-induced bolt loosening, fatigue fail-ure or down time.
The magazine you hold in your hand takes acloser look at the optimisation of bolted jointsin all kinds of industries transportation, en-ergy and offshore, with new ideas and interestingsolutions to bolt security problems. For example thespecially designed anchor bolt in the Swedish tunnelproject that will stay tight for 120 years (page 16). Orthe intricate yet simple one-nut solution in pumpmanufacturer Grundfos CR-pumps (page 12). Orthe bolts that make Vekomasroller coaster safe in the middleof the thrill (page 5). These areall examples of companies thathave spent just a little moretime on bolts and nuts
with a breathtaking resultof lowered costs, improvedefciency and product
value.
CARIN ESBERG
MARKETING MANAGER
Bolted magazine is published by Nord-Lock,and strives to increase knowledge about boltassemblies. Nord-Lock offers a unique bolt
securing system for demanding applications.The system makes bolted joints self-locking
and does not rely on friction. Nord-Lockwithstands vibration and dynamic loads.
For more information on Nord-Lock,visit www.nord-lock.com
Bolted is published twice a year in Englishand German. It is free to customers of
Nord-Lock worldwide. Published byTidningskompaniet in Gothenburg, Sweden,
www.tidningskompaniet.se
EDITOR-IN-CHIEF:Carin Esberg
EDITORIAL MANAGER:Soa Eriksson
TRANSLATIONS:Sprkbolaget www.sprakbolaget.se
PREPRESS:Tidningskompaniet
COVER PHOTO:Tidningskompaniet
Please note that unsolicited manuscripts arenot accepted. Material in this publicationmay only be reproduced with permission.Requests for permission should be sent to
the Editorial [email protected].
Editorial material and opinions expressed inBolted do not necessarily reect the views of
Nord-Lock or the publisher.
Feel free to contact us with any comments:[email protected]
Printed in Sweden by VTT Graska. Printedon UPM Finesse Gloss 100 gram and
Maxigloss 200 gram.
Bolted is issued for informational purposes.The information provided is of a general
nature and should not be treated as adviceor be relied upon for making decisions orfor use in a specic matter. Any use of theinformation provided is at the users solerisk, and Nord-Lock shall not be liable forany direct, incidental, consequential or
indirect damage arising out of the use of theinformation made available in Bolted.
04 SECURED BY NORD-LOCK07
THE EXPERTS
17 BOLTING NEWS18
QUALITY STEP BY STEP
15 Making offshore saferDropped objects are the single most commonaccident on offshore installations. Meet JohanKolst, the man who set a new safety standard.
-
8/10/2019 Bolted - 2009-EN-1.pdf
4/204 BOLTED # 1 2009
secured by NORD-LOCK
FLYING IMPACTA key piece of equipment inany pit stop, the Paoli tool istted with two pairs of Nord-Lock washers to ensure smoothand reliable operation in thishigh-vibration environment.
A MOTOR RACE can be won or lost in the pits. Thathandful of seconds when the tyres are changedand the fuel topped up are often the differencebetween spraying champagne from the podiumand limping back to the pits in defeat.
A key piece of equipment in any pit stop is
the pneumatic impact wrench, or wheel gun,which is relied on to loosen the large nut hold-ing on each wheel and then screw on a newwheel all in the blink of an eye.
Dino Paoli S.r.l, based in Reggio Emilia innorthern Italy, has been supplying Formula 1
teams with impact wrenches since 1975 and istoday a supplier to teams in a long list of racingseries around the world.
The Indy Racing League (IRL) in the US isperhaps the most demanding series for Paolisimpact wrenches; after each pit stop the tool ishurled out of the way and into a wall as the pitcrew scrambles to get its car out again. EachPaoli tool is tted with two pairs of Nord-Lockwashers to ensure smooth and reliable opera-tion in this high-vibration environment wherespeed, precision and safety are paramount.
FREE SPEED:8,600 RPM
CUSTOMER:DINO PAOLI S.R.L
A FORMULA FOR SUCCESSMAX TORQUE:2,800 NM
PRODUCT:WHEEL GUN
NUT REMOVED:
-
8/10/2019 Bolted - 2009-EN-1.pdf
5/20
SAFE CONNECTIONSNord-Lock washers about200 pairs per train areused on the steel-on-steeland steel-on-compositeconnections.
CUSTOMER:VEKOMA RIDES MANUFACTURING
AN ABSOLUTE SCREAM
HEIGHT:
33 M
MAX. SPEED:80 KM/H
RIDE:SUSPENDED LOOPING COASTER
TRACK LENGTH:
689 M
INVERSIONS:
5
THE IDEA behind a roller coaster is simple: use thelaws of physics to thrill passengers by simulatingdanger with high speeds, big drops and inver-sions. But despite the hair-raising impression ofbeing at risk, roller coasters are statistically thesafest rides in theme parks.
Netherlands-based Vekoma Rides Manufactur-ing, one of the largest builders of roller coasterswith rides at many of the worlds leading themeparks, for example the big ones in the UnitedStates, chooses Nord-Lock washers as part of itscomprehensive approach to safety. The wash-
ers about 200 pairs per train are used on thesteel-on-steel and steel-on-composite connectionswhich are subject to constant vibrations, often upto 12 hours per day, 365 days per year.
The washers ability to prevent this vibration-induced loosening of bolts, plus the fact that thewashers are approved by international certica-tion organisations, lay behind Vekomas decisionto choose Nord-Lock.
The result is an adrenaline-lled experiencethats guaranteed to make you scream withoutever exposing you to danger.
5BOLTED # 1 2009
PHOTO: VEKOMA
PHOTO: MICHAEL L. LEVITT
-
8/10/2019 Bolted - 2009-EN-1.pdf
6/20
secured by NORD-LOCK
THE WORLDS FASTEST in-service train just keeps getting faster.The latest version of Japan Railways famous Shinkansen, knownaround the world as the Bullet Train, reaches speeds of 300 kilo-metres per hour (186 mph).
As the rst Shinkansen with tilting capability to allow it to cornerat even higher speeds than its predecessors, the N700 covers the550 km between Tokyo and Osaka in just 2 hours and 25 minutes.
While riding Shinkansen N700 is a smooth and almost totallysilent experience for those on board, attaining such speeds whilecarrying more than 1,300 passengers and with a total weight ofover 700 tonnes inevitably entails considerable vibration.
To ensure that bolts do not vibrate loose, the manufacturers ofthe N700 turned to Nord-Lock washers after being impressed bytheir performance in a Junkers vibration test. Previous Shinkansenmodels used other bolt-securing solutions such as tab washers,locking wire and locking nuts. But with tens of thousands of boltsto tighten on each train, using Nord-Lock means simpler assemblyas well as safer bolt securing.
BUILT FOR SPEEDCUSTOMER:HITACHI, KAWASAKI HI, NIPPON SHARYO
TOP SPEED:300 KM/H
CAPACITY:1,323 PASSENGERS
TOTAL LENGTH:400 M
POWER OUTPUT:17.08 MW
WEIGHT:715 TONNES
SAFER AND SIMPLERWith tens of thousands of bolts totighten on each train, using Nord-Lock means simpler assembly aswell as safer bolt securing.
ALPINE OPERATIONSNord-Lock washers are used toachieve optimal locking of thebolted joints on the drive sprockets,to prevent loosening caused by theoscillating and dynamic loads.
WHATEVER SLOPE a skier can ski down, this ve-hicle can drive up. Regardless of the angle, thepitch, the bumps and the dips, the extreme coldand driving snow, nothing stands in its way.
The Leitwolf, produced by piste machine pio-neer Prinoth, based in the Grden Valley in theSouth Tyrol, is a state-of-the-art snow-groomingvehicle, boasting Pininfarina styling, immense
horsepower and sportscar-like manoeuvrability.Nord-Lock has been supplying Prinoths sub-
supplier Leripa, Austria, with washers for its all-plastic drive sprockets since 2001. The washersare used to achieve optimal locking of the bolt-ed joints on the sprockets, to prevent looseningcaused by the oscillating and dynamic loads in-volved in the most challenging alpine operatingconditions.
CUSTOMER:PRINOTH/LERIPAPISTE PERFECT
OUTPUT:435 BHP
MODEL:LEITWOLF
TORQUE:2,100 NM AT 1,000 RPM
GROOMING CAPACITY:100,000 M2 PER HOUR
ENGINE:12.8 LITRE DIESEL
6 BOLTED # 1 2009
PHOTO: PRINOTH
PHOTO: JAPAN RAIL
-
8/10/2019 Bolted - 2009-EN-1.pdf
7/20
ASKTHE EXPERTSDo you have aquestion for Boltedsexpert panel? If youwant to learn moreabout bolt securing,email your question to
OLENA KALMYKOVAAPPLICATIONSENGINEER
CSABA MADRUHEAD OFCUSTOMER TESTING
FRIDA CULLINMATERIALEXPERT
THE EXPERTSEmail your questions about bolt securing [email protected]
Q: Why do bolts and nuts rotateloose when a bolted joint is sub-
jected to vibration and/or dynamicloads?
A: Loosening of threaded fastenersdue to vibration and/or dynamicloads is an important phenomenonsince it is one of the most commoncauses for failure of bolted joints.
A tightened bolt is elasticallyelongated but strives to assume itsoriginal length, much like a spring.This can only be accomplished byrotation of the bolt/nut in the loos-
ening direction so that the boltpreload is lost. However the bolt/nut is prevented from rotating byfriction between the contact sur-faces in the threads and under the bolt head/nut.
Q: What is the difference be-tween friction-based locking andwedge locking and when is lubri-cation needed?
A: The principle of friction lock-ing is based on increased frictionin the thread or under the bolt
Why do boltsrotate loose?
Why use wedge-lockinginstead of friction based?
ASKTHE
EXPERTSDo you have a question aboutbolt securing? Put the Nord-Lockexperts to the test.
7BOLTED # 1 2009
C l a m p
l o a
d ( k N )
Torque (Nm)
Torque / clamp load test
Low deviation in achieved clamp load is essential to obtain control ofthe clamp load and to utilize the full capacity of the bolt.
Lubricatedcondition
Dry condition
head/nut. The main disadvantageof this method is increased torsionstress in the joint. High torsionmay cause the fastener to yieldat a lower preload than expected.Since friction conditions are un-even you may not reach the neces-sary preload. Insufcient preload
is the most common cause of the bolts failure, often due to fatigue.Lubricants are often used to min-imise friction and to obtain uni-form clamp load. However lubri-cation will signicantly reduce oreven discharge locking ability ofany friction-based method. Fric-tion-based locking results in littleor no control over achieved clampload.
The wedge locking method is based on tension instead of fric-tion. The most common exampleof the wedge locking system is apair of washers which have cams
with a rise greater than the threadpitch of the bolt. The washer pairis installed cam face to cam face.
When the bolt/nut is tightenedteeth grip and lock the matingsurfaces, allowing movement onlyacross the cam faces. Any rota-tion of the bolt/nut is blocked bythe wedge effect of the cams. The
wedge locking ability is not affect-ed by lubrication; furthermore byusing it you can utilise each boltto its full capacity. OK
If a joint is subjected to vibra-tions and/or dynamic loads thatcause relative movement betweenthe contact surfaces the friction is
Which washer material should I choose?Q: I have read that Nord-Lockwashers come in ve differentmaterials. How do I know whichone to use in my application?
A: It is correct that Nord-Lock washers are available in ve dif-
ferent materials. Two of the mate-rials are offered as standard and work in a wide range of applica-tions. The most common materialis a through-hardened steel washer
coated with a zinc ake coating. Wealso offer our washers in stainless
Application area Industry examplesMaterial
Steel, EN 1.71825,Zinc ake coating
A4, AISI 316L,EN 1.4404
SMO 254, AISI S31254,EN 1.4547
Inconel 718,ASTM N07718, EN 2.4667
Hastelloy/Inconel C-276,ASTM N10276, EN 2.4819
Corrosive environment
Salt water, Chlorides
High temperature
Severe corrosiveenvironments
Most stainless steelapplications
Food/Subsea/ Pump applications
Gas/Steam turbines, Heatexhausts, Turbo compressors
Chemical industries, Pulp &paper, Acidic natural gas
All purpose Machine screws
reduced because dynamic frictionis lower than static. Therefore the
bolt/nut is then no longer captivat-ed by friction and rotates loose.
The most common causes ofmovement between contact sur-faces are vibration and external dy-namic forces. CM
steel in A4 quality. The stainlesssteel washers are surface hardenedto safely secure all grades of stain-less steel fasteners. For customers
with applications in extreme envir-
onments, fasteners in special mate-rials may be needed. We offer three
special alloys upon request. Whichmaterial to choose depends on theenvironment, see below table. If youneed further assistance with choos-ing the right material for your ap-
plication, you are always welcometo contact our material expert. FC
O
O
G
O
-
8/10/2019 Bolted - 2009-EN-1.pdf
8/2088 BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
9/20
N THE MORNING OF Novem- ber 7, 1940, a wind blewthrough the Tacoma Nar-rows between Tacoma andthe Kitsap Peninsula, Wash-
ington, USA. Not an extraor-dinarily strong wind, but itstill set the newly openeddual suspension bridgeacross the narrow in motion. A local camera shop owner,Barney Elliott, took out hiscamera and recorded theincident, thereby creating a
unique historical document.It had been noted that the bridge swayed and
buckled on windy days. On this particular day,the twisting turned into a so-called torsional vi-
bration mode, eventually making the bridge col-
lapse. Fortunately, no one was killed.
O
HOW TO PICK THE RIGHT
SIZEBOLTED JOINTS In engineering, manufacturing and construction, thebolted joint is an assembly that sometimes is very much taken forgranted. When a joint uses a simple nut and bolt system as aretainer or fastener, there is sometimes a tendency to underestimatethe complexity of the system. A common mistake is to oversize thebolt, which can result in costly failure and censure.
WORDS:HUW KIDWELL
PHOTOS:TIDNINGSKOMPANIET
9BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
10/20
The bolt size used can affect how much tension canbe applied generally the larger the bolt diameter orstronger the bolt material the greater the tensionthat can be applied. DR JEFF VOGWELL,BATH UNIVERSITY, UK
A paper published in the Journal ofSound and Vibration in 2008 highlighted that
the collapse was caused by aero elastic utter-ing, enhanced by the slippage of the north mid-span cable band (loss of friction grip) which wasclamped together by several bolts that were sub- jected to forces beyond their design capacity. Thecollapse of the Tacoma Narrows Bridge has be-come a cautionary tale and a lesson for construc-tion engineering students even today.
A bolt needs to be tightened or tensioned toits design pre-load creating a clamp force on the joint to obtain the best service from it. Any devia-tion from this will cast doubt on the integrity ofthe joint. In a bolted joint the fully-tightened bolt will only bear a small portion of the external load
placed on the joint. The two ends of the scale are
a hard joint with a low stiffness bolt and a highstiffness joint material; and a soft joint with a
high stiffness bolt and a low stiffness material.In the rst case, the bolt only sustains a smallproportion of increased force from an externalsource, but in the other case, the bolt will sustainthe majority of the increased external force.
BILL ECCLES IS A consultant in bolted joints andthe founder of the British website Bolt Science, aleading provider of independent technical exper-tise in bolted joint technology. In his opinion it isimportant to understand and quantify the forceson a bolted joint and also their relationship todetermine what size bolt is suitable.
The usual function of a bolt is to apply a
clamp force to the joint so that when external
forces are applied, no joint separation or trans- verse movement will occur. The bolt is placed un-
der tension on tightening and will stretch slightlyto provide the best tensile force on the joint.
Using the largest bolt possible is not the bestsolution, according to Bill Eccles.
If too big a bolt is used not only are therecost implications, but as the bolt gets bigger fora given joint thickness the stretch in the bolt willdecrease. This is complicated by the fact that inany bolted joint relaxation or embedding loss inthe clamp force will occur, meaning that even if a bolt is tightened fully the joint material will givea little under compression over a period of timeand if a large bolt is used there will be much lessstretch in the bolt leading to possible loosening
and gap formation.
The TacomaNarrows Bridgecollapsed in the1940s due tohigh winds. Thebolts in the northmid-span cablewere subjectedto forces beyondtheir design
capacity.
PHOTO: SCANPIX
10 BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
11/20
-
8/10/2019 Bolted - 2009-EN-1.pdf
12/20
-
8/10/2019 Bolted - 2009-EN-1.pdf
13/20
PUMPS Grundfos, one of the worldslargest pump manufacturers, had aproblem. A combination of vibra-tions, high temperatures and cor-rosive liquids meant that the nylonlocking nuts at the heart of itsmachines were coming loose. Theresult for the Danish company,with its global reputation for qual-ity and reliability, was sometimespump failure. But in a chance en-counter they stumbled upon whatthey describe as a brilliant x fortheir predicament.
RUNDFOS IS ONE of Denmarks largest
companies with 18,000 employees aroundthe world, of whom about 5,000 work atits sprawling headquarters, set amonggently rolling hills in the northwest of thecountry. The company is the worlds larg-est manufacturer of circulator pumps,and also produces submersible pumpsfor pumping groundwater and so-calledCR pumps for use in industry.
It was the latter that were sufferingfrom the failure of the nylon locking nuts.This loosening of the nuts was a hugeproblem, says Segment Director General
Industry Morten Gylling. It is the smallest component in the
pump but it is also one of the most important.
GWORDS:DAVID WILES
PHOTOS:GETTY IMAGES, MARTIN MAGNTORN AND GRUNDFOS
PUMPS IT UP
13BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
14/20
We pay a premiumprice to solve thisproblem, but it allowsus to sleep at night.PER FROST VEDSTED, CHIEF ENGINEER, GRUNDFOS
Segment Director General Industry Morten Gylling (left), Grundfospump assembly (centre) and Chief Engineer Per Frost Vedsted (right)
While the nylon locking nuts worked wellup to a certain temperature, once over about 80degrees the nylon simply will not lock anymore.And then if you have a lot of vibration the lock-ing nut will also lose the pretension of the rotat-ing assembly over time. We had quite a lot offailures on pumps due to this loosening, saysGrundfos Chief Engineer Per Frost Vedsted.We needed a new design that would get rid ofthese problems.
SO GRUNDFOS ENGINEERS set about solving theproblem and came up with a number of potentialsolutions, but none proved to be ideal. And thenin a chance encounter at an industrial seminarthey came across Nord-Lock.
There was this Junker test demonstration which caught my colleagues interest, says Vedsted.We invited this company to come to Denmark so we could see it with our own eyes, and I think it
took about half an hour before we were convincedthat this could solve our problems.
Grundfos long sought-after solution wasNord-Locks bolt securing system.
It is fair to say that their concept was bril-liant but it didnt match our applications, saysGylling. Grundfos needed washers that were both harder and had a smaller inner diameter,and so engineers from both companies workedtogether for more than half a year to come up with todays solution using the high-performancealloy Hastelloy (SMO254).
FROM ORDERING 50,000 Nord-Lock washers thatrst year, Grundfos is now using 500,000 a year. And with the solution set to be used in a newpump range, that gure could be over 1 million within the next two years.
This is a great example of two companiescoming together to achieve something remark-able, says Gylling. Nord-Lock has a brilliantconcept, while Grundfos has the knowledge of themarket and the corrosion material expertise. By joining forces in an open and honest relationship
we achieved something that was a breakthroughtechnology. Nord-Lock couldnt have done it,Grundfos couldnt have done it. But by joiningthe forces we have a winning solution.
Tetra Pak is one of the companies usingGrundfos CR pumps in i ts production.
Business argumentsTHIS IS HOW Grundfos benets from Nord-Lock washers:n LOWER LIFECYCLE COST even if the ini-tial investment is highern BETTER CONTROL of the pretension onthe rotating assemblyn LOWER FRICTION lubricants can be usedn NO WEAR , such as that caused by heat,vibration and corrosivesn A TAILOR-MADE SOLUTION was made pos-sible through company collaboration.
APPLICATIONS:PRESSURE BOOSTING, BOILER FEEDING,
FACTS:
GRUNDFOS CRMULTISTAGE PUMPS
INDUSTRIES:MINING, MARINE, MACHINE TOOL, OFF-SHOR
FLOW RANGE:1180 M3/H
BOLT SECURING:NORD-LOCK
TEMPERATURE RANGE:UP TO 120C (STANDARD), UP TO 180C (VARI
WASH AND CLEAN, TEMPERATURE CONTROL
FIRE-FIGHTING, PHARMA, PETROCHEMICALCONSTRUCTION MATERIALS:CAST IRON, STAINLESS STEEL, TITANIUM
14 BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
15/20
Some might say safety isexpensive try an accident!JOHAN KOLST, SAFETY CONSULTANT
Making life safer offshoreOFFSHORE DROPPED OBJECTS arethe single most common cause ofserious accidents on offshore instal-lations. But Norwegian engineerJohan Kolst wanted to changethat. He is the man responsible forthe Statoil Hydro Health Safety &Environment (HSE) project that setthe industry standard for droppedobject management on oil rigs, sav-ing lives, time and money.Please describe the HSE projectfor which you were responsible.
Our objective was to minimise
the frequency of dropped objects onoffshore installations. There were noset guidelines at the time, so we ex-amined measures for securing looseitems and developed a droppedobject inspection system. Between2004 and 2006 we halved the fre-quency of falling objects at StatoilHydro and our best practice manualwent on to form the basis for theindustry standard in dropped objectmanagement, recom-mended by the Norwe-gian Oil Industry Asso-
ciation.Why are dropped ob-
jects a safety risk?More than 60 per
cent of the most seriousincidents on offshoreinstallations are causedby falling objects. Youhave to consider thefall-energy factor, likewhat actually happenswhen 1 kg drops 30metres...Can you give an example?
One incident I recall was whena small piece of tubing, weighingabout 30 kg, had been left un securedon an upper deck. Work was underway one deck down, but there wasa small hole in the upper deck. Thetubing was rolling back and forth onthe upper deck it fell through thehole, hit a pipe and changed direc-tion. It struck a man on the neck andhe was killed instantly.How could this incident havebeen avoided?
It is crucial to secure all loose
items! In our best practice manual,
we expressly recommend Nord-Locks bolt securing system for con-
nections that are exposed to vibra-tion, such as gratings, loudspeakers,cable trays, ladders and guide rails,but it has an almost unlimited rangeof applications. The technical sys-tem is excellent its extremely re-liable and easy to inspect. In fact,I have never heard of a Nord-Locksystem that came loose.What is special about Nord-Locksproducts?
They are unique because of thewashers. The technical design meansthe tension is always maintained and
it simply cant come loose, regard-
less of the movement or vibration towhich it is exposed.What is your advice to peopleworking with offshore safety?
Some might say safety is expen-sive but try an accident! Usuallyaccidents do not happen but, ifitems are not properly secured andinspected, something will eventuallygo wrong. The repercussions can be
terrible, in terms of both accidents
FACTS:
JOHANKOLSTAGE: 62ROLE: A consultantwith Dropped ObjectManagement Group,developing trainingand inspectionprocesses withindropped objectmanagement fororganisations in oil-related industries.
and breakages, which cost moneyand delay the work. The challengefor me and my colleagues is con-stantly to educate people its allabout a systematic approach to iden-tifying and controlling risk. If peoplework according to our best practicerecommendations and make sureloose items are properly secured,there will be no need for accidents
of this kind to take place.
Johan Kolst was responsiblefor the HSE project that led tothe current industry standard indropped object management. Heargues that bolt securing is one ofthe most crucial safety features onoffshore installations.
IN THE SPOTLIGHT
WORDS:ISABELLE KLIGER
PHOTO:GRETHE NYGAARD
15BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
16/20
THE CHALLENGE Twenty metres beneath the streets of Malm,Sweden, the new underground section of the citys central station isgradually taking shape. Currently cavernous and empty, with music fromworkmens radios echoing off the walls and the smell of concrete dustin the air, it will in December next year be a major transport hub con-necting Swedens third city with Denmarks largest, Copenhagen.
Malm Citytunnel Group, the consortium behind the project, hasdemanded that the concrete in the tunnel lasts 120 years as musteverything mounted in it, such as the gantry carrying electric cables,water pipes and ventilation pipes that run the length of the 350m-longplatform. Contractor NCC, responsible for the underground stationand platform, was tasked with nding a solution that would keep thegantry rmly bolted to the tunnels roof and able to resist the pressurewaves created by trains entering and leaving the station.
THE SOLUTION The answer was a series of steel rails cast into theconcrete of the tunnel roof. Into these rails are secured thousands ofanchor bolts manufactured by Halfen-Deha in top-quality A5 steel,each of which is secured with a Nord-Lock washer pair.
Tunnel vision
TIME RESISTANT DESIGNThe head of the bolt is slotted into therail cast into the tunnel roof. Nord-Lockwashers secure the bolt system againstforces created by trains entering and exitingthe station. This should hold for 120 years.
Light at the end of thetunnel: Malm Citytun-nel will be completed sixmonths ahead of sched-ule. About 243,000 cubicmetres of concrete wereused for its two paralleltunnels.
THE SOLUTION
We insert each anchor bolt into the rail, twist it 90 degrees, and thentighten it, says Jrgen Andersson, site engineer with NCC. This is sup-posed to hold for a very long time, so the demands on the bolts and thewashers are very high. We are counting on them to do a good job.
THE RESULT While there is much to be done before the rst train
pulls in the Citytunnel is currently six months ahead of schedule the gantry project is nished. There are 5,000 anchor bolts, paintedwith white re-resistant paint, holding the gantry solidly in place inpreparation for the buffeting created by the arrival of dozens of trainsa day passing through Malm Central Station along the 1 bn City-tunnel line.
At 5 a piece for more than a century of service, the lifecycle costis minimal.
We are pleased with the result. No problems at all, says Andersson.With the Citytunnel it would be very difcult to do repairs or main-tenance if something went wrong because it is out of the question toclose the tunnel to get access. But they wont have to worry about thisgantry for another 120 years..
WORDS:DAVID WILES
PHOTO:MARTIN MAGNTORN
16 BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
17/20
-
8/10/2019 Bolted - 2009-EN-1.pdf
18/20
bolting NEWSNews from the world of Nord-Lock and bolt security
Quality in every step
PERHAPS THE MOST IMPORTANT cor-nerstone in assuring the quality ofNord-Locks wedge locking wash-ers is the choice of material. Just asthe foundation is the most impor-tant part of a building, a productcan never be better than the mate-rial used to produce it. Daniel Eriks-son, Production Manager at Nord-Locks plant in Mattmar, Swedenexplains this concept.
We only purchase brand
steel from well-respected suppli-
ers where we know what we willget every time: above all, steelwith stable characteristics that isalways produced using the sameprocess. For the sake of the prod-uct, it is not only the compositionbut also the way in which it is pro-duced that leads to these charac-teristics.
A brand steel also has a numberof advantages over generic steel.
It is difcult to consistently
get the same characteristics in
generic steel and to get materi-al-related support from the sup-plier. When we purchase steelfrom European sources, it ismuch easier to carry on a dia-logue with the supplier and toget help in the form of know-how and support.
According to Daniel Eriksson,there are a number of factors totake into account when choos-ing a supplier. He looks at whatother customers are using, hasan ongoing dialogue with differ-ent suppliers, and he checks pricelevels, delivery times and exibil-ity. But nothing is as important asthe material.
You can get around mostof the other factors, but there isno magic way of getting a goodproduct if the material is not of
the highest quality, he says.The decision to use brand steel
was made as far back as Nord-Locks infancy in the early 1980s.The company quickly realised thatin order to guarantee the bestproducts, it was necessary to usethe best materials available.
THE STEEL is purchased exclusivelyin Europe since Asian suppliersmay not always be able to guar-antee that the material meets ENstandards.
Another important factor inchoosing a supplier, and a com-pelling argument for brand steel,is that it does not contain the ra-dioactive substance Cobalt 60.
All suppliers of brand steelcontinuously monitor the materi-als used in production to ensurethat nothing is contaminated. Allmaterial, without exception, is alsoinspected so that there is no con-tamination in the nished prod-uct either. This is also guaranteedthrough the purchase of brand
steel, says Daniel Eriksson.
Tougher competition makes ever-increasing demandsfor higher quality. Thats why Nord-Lock is workingsteadily to meet the competition and to be at the fore-front of cutting-edge development. The rst step is
choosing brand steel.
In every edition of Bolted, we present one of the areas in which Nord-Lock is working actively onquality assurance and competitiveness. In this issue we focus on the quality in the choice of material.
18 BOLTED # 1 2009
There is no magic way of getting a good product if the material is not of thehighest quality, says Daniel Eriksson, Production Manager at the Nord-Lockproduction plant in Mattmar, in the north of Sweden. FOTO: TINA STAFRN
Nord-Lock certiedby DNVNORD-LOCK IS THE FIRST bolt securingsystem in the world to have been type-approved by the independent founda-tion Det Norske Veritas (DNV). The cer-tication process has taken more thantwo years and has comprised a numberof independent tests including vibra-tion, acceleration and an overview ofNord-Locks production and its qualityassurance system.
In its decision, DNV recommendsNord-Lock for preloaded bolted assem-blies subjected to dynamic, fatigue, im-pact and vibration induced loading.
Det Norske Veritas is a global sup-
plier of services for managing risks.
General Approval fromthe German FederalRailway AuthorityNORD-LOCK has worked together withthe German railway industry and its sup-pliers for many years. Since the safetyof rolling stock and tracks, switches andbridges in the railway superstructure isgenerally of the highest priority, the Ger-man Federal Railway Authority requires
approval for component parts in the ma- jority of cases.
Since Nord-Lock has the generalapproval for the use of its washers inpredominantly non-static stressed ap-plications specic to railways, for in-dividual cases and multiple uses, therequired approvals have been waivedor signicantly simplied within theFederal Railway ambit.
Today Nord-Lock manufactureswashers for a multitude of railway appli-cations, e.g. high speed switches, noiseabatement wall anchorages, rail applica-
tions, guard rails, expansion joints, tem-porary bridges, and hardware installa-tions for railway bridge equipment, toname a few.
Deutsche Bahn AG has also con-rmed that Nord-Lock washers meetthe technical requirements for bolt se-curing systems in accordance with rail-way standard BN 208 010.
These approvals allow companiesworking with the German Federal Rail-ways to use Nord-Lock solutions with-out the requirement for individual ap-provals. Download approval through
www.nord-lock.com/downloads.
-
8/10/2019 Bolted - 2009-EN-1.pdf
19/20
Varies.
Requires heating.
Visual inspection not possible.
Up to 12 hours (increaseddowntime of equipment).
Not recyclable, containscontaminous chemicals. Maycause allergic reactions.
Unlimited (not size dependant).
Sensitive to high temperatures.
Requires degreasing.
Not possible.
Adds friction in the thread, makingit difcult to predict the clampload. Also increases the risk oftorsion.
Not possible to reuse. Bolts/nuts
needs to be cleaned before reuse,which is time consuming.
High. Relative low price perunit. Short life cycle. Increasesmaintenance costs and assemblytime.
ADHESIVESNORD-LOCK
Reliable.
No special requirements.
Visual inspection possible.
No curing time.
Recyclable. Meets ELV and RoHSdirectives.
M3-M130.
Same temperature characteristics asregular bolts/nuts.
No preparation required.
Possible to lubricate.
Linear relationship betweentorque/load thus possible to predictthe clamp load. Does not increasethe risk of torsion.
Reusable. Does not affect
reusability of bolts/nuts.
Low. Relative high price per unit.Long life cycle. Improves stabilityand minimizes maintenance cost.
CALENDaRComparing solutions for bolt securing
LOCKING CAPABILITY
DISASSEMBLY
VISUAL INSPECTION
CURING TIME
ENVIRONMENT
RANGE
TEMPERATURE
ASSEMBLY
LUBRICATION
CONTROL OVERCLAMP LOAD
REUSABILITY
LIFE CYCLE COST (LCC)
Adhesives or Nord-Lockwashers? Finding theultimate bolt securingsystem is no easy task.Here is a guide to makingthe right choice.
Download CAD-lesfor Nord-Lock productsIF YOU NEED a CAD-le for any Nord-Lockproduct, you can easily download 2Dand 3D CAD models in several formatsvia the Nord-Lock site. Pdf-les can begenerated for each product, with thor-ough product information, date and ar-ticle number. Youll nd the CAD-library
at www.nord-lock.com/cad.
This zinkaked NL6spwasher paircan easily bemade into a3D CAD model.
ExhibitionsEACH YEAR , Nord-Lock partici-pates in over 60 large exhibi-tions and events for various in-dustries. In the Nord-Lock standsyou will nd experts on bolt se-curing, and you can also see Jun-ker demonstrations, a compara-tive worst-case scenario test forbolted joints. Here are some ofthis autumns highlights:
SPE Offshore Europe,Aberdeen, ScotlandWHAT: the largest upstream oiland gas event outside NorthAmerica, with conferences, de-bates and demonstations of thelatest well technology.WHEN: Sep 811, 2009WHERE: Stand no. 866
Agritechnica,Hanover, GermanyWHAT: the worldwide meetingpoint for the agricultural machin-ery sector.WHEN: Nov 1014, 2009WHERE: Stand no. 07-B24
Power Gen Show,Las Vegas, USWHAT: knowledge and ideas onthe latest power industry trendsand challenges.WHEN: Dec 810, 2009WHERE: Stand no. C5-538
Youll nd the complete list ofexhibitions atwww.nord-lock.com/events.
19BOLTED # 1 2009
-
8/10/2019 Bolted - 2009-EN-1.pdf
20/20