The internal combustion engine is a marvel of engineering. It’s ubiquitous because it’s so useful. You probably won’t appreciate the lengths they’ve gone to just to limit the noise and vibration that are inherent in the sheer violence at its heart. Take your car engine. Imagine what it would sound like without oil (and little time it would last..), the sound absorbing linings of your engine bay and the exhaust silencer (modern silencer seem to last longer than they used to – a blown silencer was a common occurrence years back). Imagine too how much vibration would be transmitted without engine mountings and panel supports. You may have noticed too – especially on older cars and motorcycles, the amplitude of that vibration may get especially large at certain speeds as it seems the whole car/bike seems to join the party.
This element is all about that sort of thing. I love the fact that noise and vibration are treated together – because that’s how they occur. Simplistically, noise is transmitted as vibrations in matter – it’s fundamentally the same thing though we perceive them differently.
The National Diploma B6 starts straight away by adopting the better layout of the International equivalent. We get the familiar jaunt through the basic concepts – though items about noise dose concepts are now moved to here where they more naturally fit.
The effects of noise on people have been expanded to make it more explicit – so the specific conditions of are mentioned now (like NIHL and tinnitus). You’ll notice that the measurement and assessment of noise is now much reduced. It combines the best bits of the national and international diploma but deletes the detail on the operation of the equipment (this being replaced with a reference to using noise consultants, which is what tends to happen). So it’s got a bit more realistic.
The section on control of noise, again adopts the international diploma layout which adopts the familiar tripartite treatment of noise at source, in the transmission path and at the receiver. Active noise cancellation methods make an appearance here.
The section on vibration pretty much follows the same design (unsurprisingly), mostly again choosing the better international diploma layout where it can. The vibration measurement and assessment again takes out the detail, referring to vibration measurement specialists. I’d like to see in here too a mention of the issue of anti-vibration gloves. Not because they are part of the solution, but because there’s much mythology about them and they are most certainly out there on the market. As far as I can see from various HSE research reports and a recently revised standard on these gloves – there might be something in it but the certification testing maybe flawed (real vibration happens in 3D and depends on how hard you grip and the damping, if any, is only in a fairly narrow window). Nonetheless, safety people probably need to be aware of the arguments either way – because they’ll encounter it sooner or later as a suggested solution by someone.