The usage time is an important part of the specification for products powered bybatteries. The usage time is affected by a number of different elements; technical,environmental and how the product is being used. The method to determine theusage time is intended to define how measurements and calculations are to berealized along with influencing factors to keep in mind. With support from thismethod the intention is to gain control on how well the established usage time canbe expected to cohere with the real value and what affects the value.The study is done specifically for hearing protectors with battery powered built inelectronically functions. The functions can be level dependent function forambient hearing, 2-way radio communication, Bluetooth or FM-radio.The first chapter of the report describes the literature study performed in theproject. This study handles factors affecting measurements, factors with need tobe considered in the measurement situation and how deviations are handled.The following chapter begins with a description on previously used measurementtechniques for determination of the usage time. This is followed by a descriptionof three different methods developed in this project. A description of a couple ofmeasurements performed to investigate factors that affects the usage time is alsoincluded in this chapter.In the chapter describing the analysis of the study, the three methods developed inthis project are analyzed. This analyze is performed with the formulation ofquestion for the project, what has appeared in the literature study and themeasurements performed.The summary from the project includes factors affecting the measurement andhow to handle deviations in order to keep them as low as possible. The differentfunctions in the products affects the usage time in different proportions. Themost prominent factors are the balance of how much different functions are beingused when the usage time are decided, how batteries behave in different situationsand how the measurement equipment and the connection of the same affects themeasurement result.As part of the summary the advantages with one of the three methods developedare described and compared to the other two developed test methods. Thepreferred method uses usage time logging in real time during a test situation wherethe product is controlled to work in a situation trying to emulate normal use.

De senaste åren har det skett stora framsteg i byggbranschen från sedvanlig byggprojektering till avancerad BIM-projektering. Resultatet av denna studie visar att trots den hastiga utvecklingen så utförs det fortfarande mängdavtagningar ur 2D-ritningar. Detta på grund av problem som uppstår vid mängdavtagningar ur objektbaserade 3D-modeller. Mängdlistorna ur objektbaserade 3D-modeller stämmer inte alltid överens med mängdlistorna ur 2D-ritningar. Detta leder i sin tur till nödvändiga och tidskrävande manuella mängdavtagningskontroller ur pappersritningar. Detta för att säkerhetsställa den riktiga mängden. Ju större projekten blir, desto mer tid tar det att utföra de manuella mängdavtagningskontrollerna.  Syftet har varit att lokalisera och analysera de olika felkällorna som uppkommer vid mängdavtagningar. Mängdavtagningsfunktionen i programmet RevitMEP (2014) och MagiCAD (2013.11) undersöktes. Resultatet jämfördes med manuella mängdavtagningar ur 2D-ritningar.         Examensarbetet resulterade i en arbetsmodell som visar hur man på ett korrekt sätt utför mängdavtagningar ur 3D-modeller. Vinsten av detta blir att färre återkommande fel uppstår. Det är viktigt att ha ett välstrukturerat och tydligt arbetssätt vid användning av de olika BIM-verktygen. Vid användning av modellen blir det färre fel och minskad missförstånd uppstår vid projektering. Kontinuerliga mängdavtagningar bör genomföras för att så tidigt som möjligt möjliggöra upptäckten av fel. Att upptäcka felen i ett tidigt skede förhindrar att felet eskalerar. I studien påträffades även ett kritiskt programmeringsfel i programmet MagiCAD för Revit MEP vilket ger användaren felaktiga resultat. Problemet har påpekats till programutvecklaren CADCOM och korrigering av programmet kommer att ske. / The past years there have been vast progresses within the construction industry from traditional construction projection method to a more advanced BIM-projecting method. The results of this dissertation shows that in spite of these vast progresses it is still commonly conducted manual quantity calculations with 2D-drawings. The main reason to this is that when you compare the quantity results from object based 3D models to manual quantity calculation results with 2D-drawing, the results do not add up being equal to each other. Hence time consuming manual quantity calculations with paper drawings has to be conducted to verify the real material quantity. The larger the project, the more time is consumed to conduct manual calculation verification. The aim has been to identify and analyze the different sources of error arising from manual calculation verification. In assistance we used the quantity calculation functions in the software RevitMEP (2014) and MagiCAD (2013.11). To substantiate the results manual calculations were conducted. The results were compared to the manual calculations from 2D drawings, the profit of the method is that we get less reoccurring errors. The gain of this is resulting in fewer recurring of errors. It is important to have a well-structured and clear approach with the use of the various BIM tools. When using the model, there are fewer errors and reduced misunderstandings arise during project planning. Continuous calculation verifications should be implemented as early as possible to allow the discovery of errors. Detecting errors in the early stage will prevent the error from escalating. The study also found a critical programming error in the program MagiCAD for Revit which gives the user false results. The problem has been pointed out to the application developer CADCOM and correction of the program will occur.