Rank: Guest 
|
Posted By P. Moore
All
I am attempting to calculate the Lepd (via the HSE's noise exposure calculator) for a hedge trimmer.
The manufacturer's specification quotes two figures:
(1) a sound pressure level in Lpeq to ISO 11201 of 89 db(A),and
(2) a sound power level in Lpeq to ISO 3744 of 102 dB(A).
How does Lpeq correspond to the Laeq which I neeed to input into the HSE calculator?
Also, which quoted figure should I use?
Any help would be much appreciated.
|
|
|
|
|
|
Rank: Guest
|
Posted By Alan Hoskins
My understanding that both terms refer to continuous equivalent sound levels.
It's the sound pressure level that you need for the calculation.
(not an expert)
Alan
|
|
|
|
|
|
Rank: Guest
|
Posted By Adrian Watson
Lpeq is the time-averaged emission sound pressure level. BS EN ISO 11201:1999 specifies a method for measuring at the the operators work station. EN ISO 3744:1994 specifies a method for calculating the sound power emitted by a machine by measuring the sound pressure level in a free field.
Use the Lpeq from BS EN ISO 11201:1999 and put in the time for the operators exposure period.
Regards
|
|
|
|
|
|
Rank: Guest
|
Posted By Bob Y
It's been a little while since I did my noise course or an assessment but LEQ is the average sound level over the measured period; the 'A' means that it is an A weighted measurement.
I have not come across LPEQ and am personally wary of using the manufacturers data and suggest that you take your own measurements (if possible) in the hearing zone using the machine in operation. I feel that this would give you a more accurate result
|
|
|
|
|
|
Rank: Guest
|
Posted By P. Moore
Thank you all.
A supplementary question:
How do I get from this Lpeq/Laeq to the Lc value to use the HSE's SNR hearing protection calculator?
|
|
|
|
|
|
Rank: Guest
|
Posted By Bob Y
You need to get the SNR value for the ear protection that you intend to use from the manufacturer. You will also need to measure the c weighted sound levels and then input these into the HSE spreadsheet. This will give you the predicted sound level 'under' the ear protection. The HSE then add 4 dB for 'real world' factors - this is because the level of actual attenuation/protection doesn't often meet the theoretical values published.
|
|
|
|
|
|
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.