Control of Environmental Noise

Question 1

what is the definition of environmental noise?

Answer 1

unwanted sound

Question 2

what are the key sources of noise?

Answer 2

• manufacturing and related commercial activities
• transport
• agriculture
• construction
• quarrying and mining
• pubs and clubs
• neighbours
• rural activities

Question 3

what are the basics of acoustics?

Answer 3

• sounds are the result of air being continually compressed followed by rarefaction
• the frequency or number of times the compression takes place per second will determine the pitch
• the pressure exerted by the energy input will determine the loudness
• the pressure fluctuation of sound may be described as a sine curve or wave

Question 4

what is ‘pressure’

Answer 4

‘sound’ is the sensation which the brain perceives when pressure variations in the air are detected by the ear

Question 5

what is frequency

Answer 5

‘hertz’ - the number of times a vibrating system completes a cycle of movement in one second

Question 6

what is sound

Answer 6

the transmission of energy as vibration, loudness depends upon the sound pressure and frequency

Question 7

Define a wavelength

Answer 7

the speed of sound divided by the frequency

Question 8

what is amplitude

Answer 8

is proportionate to the energy of a sound wave

Question 9

what is pitch

Answer 9

describes the type of sound we hear

Question 10

what is inetnsity

Answer 10

the rate of energy flow per unit area transmitted bas a sound wave

Question 11

what is power

Answer 11

sound power level (SPL) is the total energy per second expressed in decibels (dB)

Question 12

how is sound measured?

Answer 12

as a sound pressure in dB

Question 13

what is the lowest sound a human can hear?

Answer 13

1x10-12 Watts per m2 when the sound frequency is 1000Hz

Question 14

describe the Bel(b) and deciBel (dB) scale

Answer 14

the Bel is very large and is therefore divided by 10 to give a deciBel.

Sound is measured on a logarithmic scale

an increase in 3dB doubles the sound intensity
a decrease in 3dB halves the sound intensity

Question 15

Describe noise weighting scales

Answer 15

meters are designed to measure sound and mimic the human ear.

usual scale of measurement is corrected or ‘weighted’

the most usual weighting is ‘A” scale. i.e. dB(A)

Question 16

What are Percentile Sound Levels?

Answer 16

percentile Exceedance Sound Level (Ln) is used to express the amount of time a certain level of noise is exceed (eg L10 is the level exceed for 10% of the time period)

Question 17

What is Equivalent Continuous Sound Level (Leq)?

Answer 17

an average of the energy of sound.

The noise dose received by a person is the product of the noise level and the duration of the exposure

Question 18

What legislation established the upper and lower exposure limits values

Answer 18

The UK Control of Noise at Work Regulations 2005

Question 19

What is Narrow Band Noise?

Answer 19

noise that has a limited range of frequencies within an audible range. Due to its nature it tends to have a high nuisance value. (screams, whistles, hisses, etc)

Question 20

What is Low Frequency Environmental Noise?

Answer 20

this tends to be be between 20-160Hz and may cause distress, sleep deprivation dn depression to susceptible people

Question 21

ISO 1996 is what?

Answer 21

standardised measurement of environmental noise

Question 22

what is BS4142:2014 + A1:2019

Answer 22

the standard that can be used to assess the impact of industrial and commercial sound sources

Question 23

what is the method for BS4142:2014 + A1:2019

Answer 23

• the specific sound under investigation is measured and a rating added if the sound has a characteristic likely to increase the significance of the impact (known as a rating sound)
• background sound levels are then measured
• the difference between the rated sound and there background sound level is used to assess the significance of the impact

Question 24

what are the main factors that affect the perception of noise

Answer 24

• loudness
• pitch
• incidence
• background lelves

Question 25

what are the main complaints of neighbourhood noise?

Answer 25

• ASB
• poor planning controls
• juxtaposition of incompatible land uses
• specific one-off events
• sirens or other noise interfering with with use of tannoy systems for communication

Question 26

what can by the impacts of environmental noise on people?

Answer 26

• annoyance
• sleep disturbance
• cardiovascular problems
• performance and educational achievement

Question 27

What are the reasons to control noise?

Answer 27

• protect the health of wworkers
• reduce the chance of nuisance
• comply with environmental, H&S legislation
• comply with the requirements of formal environmental management system
• ensure good relations with those living close to the site

Question 28

What are examples of management controls?

Answer 28

• control working hours
• control use of radios
• control of public address systems
• alternative vehicle routing
• keeping loading doors and shutters closed