Haarup Maskinfabrik

    Maskinstøjsmålinger for Haarup Maskinfabrik

    Maskinstøjsmålinger er vigtig dokumentation til kunderne. Haarup Maskinfabrik fik foretaget professionelle støjmålinger af deres betonblander VM750L. Nu kan de overfor deres kunder dokumentere, at deres maskine er støjsvag, og at støjen fra deres betonblander ikke kræver, at man anvender støjværn.

    Af Nanna Bastved

    Haarup Maskinfabrik er en succesfuld producent af blandeanlæg til betonindustrien. For nyligt henvendte én af deres kunder i Tyskland sig til Haarup Maskinfabrik og bad om dokumentation for maskinstøjen for Haarup Maskinfabriks betonblander VM750L, så kunden kunne vise papirerne til Arbejdstilsynet i forbindelse med en arbejdsmiljøinspektion.

    Da de pågældende støjmålinger for modstrømsblanderen var en del år gamle, besluttede Haarup Maskinfabrik at benytte lejligheden til at få opdateret deres dokumentation og bad DELTA foretage nogle nye støjmålinger.

    ”Vores maskiner skal følge bestemmelserne i Maskindirektivet og overholde relevante standarder for de maskiner og anlæg, vi fremstiller. Selvom vi kender indholdet af bestemmelserne, havde vi brug for nogle eksperter, der kunne udføre målingerne korrekt,” fortæller Jan Kjær-Hansen, Technical Writer hos Haarup Maskinfabrik.

    On-site-målinger

    Udfordringen var, at modstrømsblanderen er en stor, tung maskine, der er svær at få bakset ind i et testrum. Derfor foretog DELTA målingerne on-site i Haarup Maskinfabriks produktionshal. Det betød, at der både skulle foretages referencemålinger af rummets indvirkning (som støjmålingerne blev korrigeret for) og støjmålingerne af selve maskinen i brug.

    ”Opgaven blev udført meget professionelt. DELTA’s konsulent satte sig grundigt ind i målemetoden beskrevet i C-standarden for betonblandere og gav os helt præcise anvisninger til måleopstillingen, fx hvor blanderen skulle placeres i forhold til vægge, loft og andet fast inventar, således at målingerne kunne gennemføres i vores produktionshal. De meget konkrete anvisninger var vigtige for os for at undgå, at der opstod nogle misforståelser undervejs,” udtaler Jan Kjær-Hansen.

    Måling af kildestyrke og lydtrykniveau

    DELTA målte både lydeffekten (dvs. kildestyrken) og lydtrykniveauet fra maskinen. Lydeffekten, som måles efter ISO 3740-serien, bruges til at angive, hvor meget støj maskinen bidrager med. Lydtrykniveauet, som måles efter 11200-serien, er en standard for operatørstøjniveauet og angiver om operatøren af maskinen bør anvende høreværn.

    ”Da C-standarden specificerer, at man skal måle hele blandingscyklussen, målte DELTA kildestyrken fra maskinen i tre faser: påfyldning, selve blandingen og tømningen af maskinen,” fortæller Jan Kjær-Hansen og tilføjer: ”DELTA’s målingsbesøg var meget smidigt og veltilrettelagt og forstyrrede os minimalt i produktionen.”

    Støjniveauet er nu dokumenteret

    Resultaterne af målingerne blev modtaget positivt hos Haarup Maskinfabrik, som nu har dokumentation for, at støjen fra deres betonblandere ikke kræver, at man anvender støjværn:

    ”Vi fik bekræftet, at vores blandere er meget støjsvage, idet lydtrykniveauet ligger under grænseniveauet på 80 dB(A),” udtaler Jan Kjær-Hansen og tilføjer, at kunderne selvfølgelig stadig skal vurdere maskinstøjen i sammenhæng med de fysiske forhold og øvrige støjkilder for operatørerne på de konkrete anlæg.

    Efterfølgende har Haarup Maskinfabrik sørget for at revidere produktmanualerne med den nye dokumentation, så deres kunder fremover kan fremvise opdateret dokumentation for maskinsikkerheden til myndighederne.

    Yderligere information om støj- og vibrationsmålinger

    DELTA er akkrediteret til at udføre støjtest og udfører mange forskellige typer af maskinstøjs- og vibrationsmålinger for bl.a. energisektoren, produktionsvirksomheder, maskinbyggere og marine/off-shore-branchen. DELTA er desuden notificeret i EU til at udføre støjtest efter Maskinstøjsdirektivet 2000/14/EC.

    Mange af de støj- og vibrationsmålinger, som akustikerne foretager, foregår i DELTA’s godkendte testfaciliteter. Fordelen ved at anvende disse kontrollerede testrum er, at det akustiske miljø er kendt, hvilket sikrer, at rummets indvirkning på støjmålingerne ligger under grænseværdien.

    Mere info

    For yderligere information om målinger af maskin- og vibrationsstøj kontakt enten Morten Bording Hansen, specialist, tlf. +45 72 19 45 56, mbh@delta.dk eller Leif Ødegaard, seniorspecialist i akustik, tlf. 72 19 43 00, lod@delta.dk.

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    ENGLISH VERSION


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    Measured sound emissions from machinery is important documentation for customers

    Haarup Maskinfabrik obtained professional sound emission measurements of its concrete mixer VM750L. Now the company can provide documentation to its customers that the sound emission level is below the permitted maximum value, which means the machine operator does not need to wear hearing protectors.

    By Nanna Bastved

    Haarup Maskinfabrik is a successful company that manufactures mixing equipment for the concrete industry. Recently, one of Haarup Maskinfabrik’s customers in Germany contacted the company and asked for documentation for the sound emission level of the company’s concrete mixer VM750L, so that the customer could submit the documentation to the Working Environment Authority in connection with a working environment inspection.

    As the associated sound level measurements for the counter flow mixer were a few years old, Haarup Maskinfabrik decided to take the opportunity to have their documentation updated and asked DELTA to carry out new sound level.

    “Our machines must comply with the provisions in the Machinery Directive and comply with the relevant standards for machinery and equipment that we produce. Even though we know the contents of the provisions, we needed experts who could carry out the measurements correctly,” says Jan Kjær-Hansen, Technical Writer at Haarup Maskinfabrik.

    On-site measurements

    The challenge was that the counter flow mixer is a large, heavy machine, which is difficult to manoeuvre into a test room. Therefore, DELTA made the measurements on-site, at Haarup Maskinfabrik’s production centre. Consequently, DELTA made both reference measurements of the room’s acoustic properties (used for correcting the sound measurements) and sound measurements of the actual machine in use.

    “The task was carried out very professionally. DELTA’s consultant thoroughly looked into the measuring method described in the C standard (red. EN12151 Annex C) for concrete mixers and gave us precise instructions for the measurement set-up, for example, where the mixer should be positioned in relation to walls, ceiling, and fixtures, so that the measurements could be conducted in our production room. The very specific instructions were important for us, to avoid any misunderstanding along the way,” says Jan Kjær-Hansen.

    Measurement of sound power level and sound pressure level

    DELTA measured both the sound power level and sound pressure level at the machine. The sound power level, which is measured in accordance with ISO 3740 series, is used to state how much noise the machine generates. The sound pressure level, which is measured in accordance with the 11200 series, is a standard for the operator noise level, and states whether the machine operator should use hearing protectors.

    “Because the C standard specifies that you must measure the entire mixing cycle, DELTA measured the sound power from the machine in three phases; filling, the actual mixing, and emptying of the machine,” says Jan Kjær-Hansen. He adds: “DELTA’s measurement site visit was very flexible and well-planned and caused a minimal of interference with our production.”

    The noise level is now documented

    The results of the measurements were positive news for Haarup Maskinfabrik, which now have documentation showing that the noise from the concrete mixers do not require that the operator use hearing protectors:

    “The measurements showed that the sound pressure level was below the threshold limit of 80 dB(A), as thus confirmed that our machines emit a low level of noise,” says Jan Kjær-Hansen, who adds that obviously, the customers must still assess machine noise in the context of the physical environment and other sources of noise at their particular facilities.

    Haarup Maskinfabrik has subsequently ensured that the product manuals have been revised with the new documentation, so that from now on, its customers can submit the updated documentation for the machine safety to the authorities.

    Further information about noise and vibration measurements

    DELTA is accredited to carry out noise tests and conducts many different types of machine noise and vibration measurements e.g. for the energy sector, manufacturing companies, machine manufacturers, and the marine/off-shore sector. Furthermore, DELTA is notified in the EU to conduct noise measurements in accordance with the Directive 2000/14/EC – equipment for use outdoors.

    Many of the noise and vibration measurements, conducted by the acoustic engineers, are carried out in DELTA’s approved test facilities. The advantage of using these controlled test rooms, is that the acoustic environment is known, which ensures that the room’s acoustical properties are less than the threshold test limit.

    More info

    For more information about measurements of machine noise or vibration noise contact Morten Bording Hansen, specialist, tel. +45 72 19 45 56, mbh@delta.dk or Leif Ødegaard, Senior Specialist in Acoustics, tel.: +45 72 19 43, lod@delta.dk.

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