mast met microfoons aan een paal in het water met een boot ernaast

Creative Solutions to Measurement Practice Challenges (41/50)

Our measuring technicians Patrick Boelens and Patrick Meelen frequently encounter it. Colleagues sell the client a beautifully designed noise study - and then the pair have to figure out how to make good on this promise in the face of uncompromising practical realities. Fortunately, both of them are, by now, able to draw on over 14 years of experience when coming up with creative solutions.

Take, for instance, road or rail traffic noise measurements over bridges to determine how much extra noise the bridge creates. In accordance with testing standards, microphones for this purpose have to be mounted exactly 7.5 metres from the middle of the road or railway track. Boelens: 'Surprisingly, this often works out just fine because we can use an adjacent bicycle bridge, for instance. But it also happens quite often that the microphone actually has to be suspended overhead anyway.'

Self-Made Constructions

'So we have had to come up with some creative constructions for that over the years. I once made a small gate with hinges that you could unfold from the bridge. On top, I had attached a beam which you could use to extend the microphones even further. Other times, we had to take a boat out onto the water, for example, to attach a microphone to a mast on a pole in the water or to attach measuring equipment to the underside of the bridge. We also had to work a little magic on the boat so as to be able to properly access the equipment.’

hekje met microfoon boven water uitgeklapt vanaf een brug

In a Cherry Picker

But even without water nearby, measuring along the road presents challenges. Meelen: 'Similar problems occur at viaducts. I once stood next to one in a cherry picker with equipment to measure at the correct height. Another issue is not being able to put anything on the hard shoulder for safety reasons. Sometimes, this lane is so narrow that our microphones still have to be suspended above it in order to comply with the test standard. This is why we have occasionally installed a stand on the verge with PVC pipes at different heights across so as to still be able to get the microphones in the right place.'

Patrick met meetapparatuur in een hoogwerker naast een viaduct
mast in de berm met op twee hoogtes microfoons boven de vluchtstrook

Satellite Imaging Helps

Nowadays, applications like Google Maps help enormously in getting a better advance assessment of the possibilities on location. Boelens: 'Previously, we had to go to the location in order to assess the situation. Now, you can determine in advance from satellite imaging whether there is anything to attach equipment to within 7.5 metres of the middle of the bridge, for instance. This way, you just have to check the measures on the job. Usually it's exactly right.'

Junction Unravelled

Meelen: 'We also once used Maps to determine a suitable route during a whole series of asphalt measurements at one of these complicated intersections with multiple curves near Rotterdam. Otherwise, we really would have had to drive around in circles trying to figure out which road would take us to the desired measurement points. Fortunately, technical developments have made our work a lot easier in that respect.'