The Mayor's Ambient Noise Strategy - Greater London Authority

264 Mayor of London
The Mayor’s Ambient Noise Strategy
Under Government proposals, they may be replaced by Local
Development Frameworks.
Urban street canyon see Street canyon.
UIC Union International de Chemins de Fer, international
railway organisation.
Vibration Is the oscillation of a mass in relation to a reference point,
perceived by people other than by hearing (see Appendix A2).
Westerly operations When aircraft make their final approach to land
from the east, and take off towards the west.
Westerly preference A system of westerly preference was introduced at
Heathrow in 1962. It means that aircraft land from the east, and take off
towards the west, unless wind direction and speed is such as to require
operating in the reverse direction (easterly, see above). Optimally, aircraft
take off and land into the wind, but can both take off and land with a
moderate tail wind. Westerly preference at Heathow reduces the number
of take offs over the more highly populated areas east of the airport.
Work-Live Such units may be seen as an intermediate step between
working at home and using a separate small business unit. The business
area may occupy 50% or more of total internal floor area, and be clearly
separated from the residential element. The work space would include
standards of noise insulation, ventilation, services and provision for
equipment capable of accommodating a range of business uses which
would not normally be acceptable in a home. See also Live-work.
Worst mode noise contour On a long term average basis, aircraft
operations at Heathrow are predominantly westerly, i.e. most of the time,
aircraft land and take off towards the west. On a 20 year basis, some 77%
of summer movements have been westerly, and 22% easterly. However, in
any particular year, wind direction can be such that easterly operations
can be a much higher proportion of total movements. A ‘worst mode’
noise contour might assume that operations were wholly easterly (e.g.
typical easterly day), for certain planning purposes.