Examination of Witnesses (Questions 5820
- 5839)
5820. Turning to mitigation measures at the
receptor end, on the screen is the noise and vibration mitigation
scheme Information Paper D9.[6]
What are the mitigation measures that are proposed at that stage
of the works?
(Mr Thornely-Taylor) The noise
and vibration mitigation scheme effectively puts into practice
the discretionary power to provide noise insulation from construction
noise that appears in the noise insulation regulations for railways.
The works included are specified in those regulations and in short
they are the provision of secondary glazing, the provision of
a noise attenuated ventilator and, in appropriate circumstances,
secondary doors, and in the space between the two panes and secondary
glazing there is provision for Venetian blinds to reduce solar
gain.
5821. In terms of the mitigation you have just
described what is it intended to achieve in terms of the internal
noise environment within the affected properties?
(Mr Thornely-Taylor) I will answer that in
two ways. One is an historical one in that all these insulation
schemes have been introduced with the intention of applying them
equitably across major infrastructure schemes. The original one
was highways and the purpose was to provide noise mitigation when
the predicted noise exceeded the acceptable. Put in more general
terms, the objective is to make it possible to continue to occupy
a building in a reasonable manner throughout the works without
unacceptable interference by noise.[7]
5822. In circumstances where even if such insulation
measures were provided and taken up that objective would still
not be achievable is there any further mitigation that the Promoter
is proposing to offer?
5823. (Mr Thornely-Taylor) The
further mitigation is the temporary re-housing scheme when, even
after providing secondary glazing, the internal noise levels would
not meet the criteria I have just mentioned and then temporary
re-housing would be offered.
5824. By what criteria is the judgment made
as to whether either noise insulation package or in appropriate
cases temporary re-housing is offered to affected householders?
(Mr Thornely-Taylor) There is a formal process
which takes place much closer to the start of construction than
we are now when the contractor is known, his methods of working
are known and detailed predictions are made and it is set out
in an appendix to Information Paper D9, a very formal process
for identifying whether or not the noise will exceed bigger levels
for the required duration.
5825. Mr Mould: Are those levels prescribed
noise levels which effectively operate as a trigger in relation
to eligibility for noise insulation or, in appropriate cases,
temporary re-housing?
(Mr Thornely-Taylor) Yes, they are.
5826. That being the mechanism, is it appropriate
that there should be some arbitral regime in relation to eligibility
for one or other or both of those packages of mitigation?
(Mr Thornely-Taylor) Effectively, there are
two stages to that. There is a procedure for applying to the Secretary
of State if a person believes they should be entitled and have
not been offered either noise insulation or temporary re-housing.
Should the Secretary of State decline that application and the
person applying feel aggrieved, there is the separate process
of the Independent Complaints Commissioner, who would be available
to receive a complaint of that kind.
5827. For the Committee's note, that is information
paper F5.[8]
Finally on noise and vibration mitigation, does that reflect a
model that has been deployed effectively in relation to other
major infrastructure projects?
(Mr Thornely-Taylor) It is very
similar, differing only in detail, to those used for the Jubilee
Line extension and the Channel Tunnel Rail Link, to name but two
of the major recent infrastructure projects.
5828. Can we just pick up on the position in
relation to Mr and Mrs Ennals at 69 Hunter Avenue?[9]
On present assessment, can you help us with their eligibility
for one or other or both of those mitigation packages?
(Mr Thornely-Taylor) If I remember
rightly, Mr and Mrs Ennals live two houses away from the north-eastern
end of the work site. I think it is the right of those two houses.
5829. I think it is the property which is adjacent
to the north end of the works.
(Mr Thornely-Taylor) I have a feeling the arrow
needs to move one house to the right, as I heard the evidence.
Those two houses are currently identified in the Environmental
Statement as being eligible for noise insulation. As I have mentioned,
that is not by any means the beginning and end of the story. The
actual entitlement procedure will be gone through much closer
to the start of the works.
5830. Thank you very much indeed for that. Finally,
turning from construction noise to operation noise, so the railway
is up and running, trains coming in and out of Shenfield, can
you tell the Committee what the results of the environmental assessment
process were in relation to the impact of Crossrail at that stage?
(Mr Thornely-Taylor) Yes. There is a statutory
procedure for calculating railway noise which was used in the
preparation of the Environmental Statement. Taking account of
the changes in train numbers, the revision of the track layout
and the new train services, the change in noise level was predicted,
and in all cases was found to lie well below the threshold of
significant effect as set out in the Environmental Statement.
5831. What is the dominant noise environment
for those living within 100 or so metres of the railway line at
the moment?
(Mr Thornely-Taylor) Train noise is the major
source for the properties that are considered for potential significant
effects. The levels are not excessively high. They are set out
in the environmental statement, but it is the main noise source
in the area, except for those very close to the road, who may
have more traffic noise than train noise.
Cross-examined by Mr Welfare
5832. Mr Welfare: Mr Thornely-Taylor,
in response to Mr Mould, you described to the Committee a moment
ago the position of significant effects being the basis of the
noise assessment over a distance and the factor of length of time,
and you pointed to the fact that audibility is not the same as
significance, and you have helpfully clarified that the elevated
area of the Shenfield area is outside what are regarded as significant
effects.
(Mr Thornely-Taylor) Yes.
5833. It follows from that, does it not, that
noise disturbance, be it during the construction period or during
the operation thereafter, in terms of what individual people suffer
in their houses, can take place with no compensation arrangements
at all?
(Mr Thornely-Taylor) Yes, it can.
5834. In fact, just to reinforce that point,
you have said that the distance involved was the distance within
which there was the need to restrict the work of computation so
that one could be sure that there would be effects. In other words,
you start from the position of over what area can we be certain
there will be noise effects and measure within that area, and
you treat those outside that area as not falling within significant
effects. Is that right?
(Mr Thornely-Taylor) It is the other way round.
The distance is chosen so that one can be certain it includes
significant effects. If for some extraordinary reason one found
significant effects going over the edge of the spatial boundary,
then it would be necessary to go back and change the spatial limits,
but that has not happened.
5835. Would you care to explain to the Committee
how the significant effects are determined?
(Mr Thornely-Taylor) Yes. They are determined
according to whether or not the noise would exceed either a minimum
trigger level or significance or a change in the total noise level
relative to the baseline, ambient noise as set out in the scope
of methodology of the ES.
5836. Can you give the Committee some idea of
the basis of a significant level of noise?
(Mr Thornely-Taylor) There is detailed explanation
of the thought processes that underlie it in Appendix D of the
special technical report, which can be found on the internet,
but it is traceable to guidance from documents published by the
World Health organisation, British Standards, and current practice
in environmental assessment. They are very well established sets
of numbers.
5837. I do not disagree with what you are saying
in terms of there being well established sets of numbers, but
from the point of view of an ordinary resident who seeks to understand
what the Promoters regard as a significant effect or what indeed
is to be generally regarded as a significant effect, where in
what Crossrail have put forward so far to individual residents
has there been an explanation of what significance can be expected
and what levels of noise people will have to put up with?
(Mr Thornely-Taylor) In the Environmental Statement.
5838. Yes, but in terms of trying to give people
an understanding of what that amounts to, are you satisfied that
residents have been put in a position to understand in plain terms
what levels of noise they will be expected to accept?
(Mr Thornely-Taylor) It was clear to me, listening
to petitioners yesterday, that there is some misunderstanding
and there may be some confusion between audibility and significance.
5839. In other words, residents may have to
put up with a degree of noise which is not significant?
(Mr Thornely-Taylor) They will, yes.
6 Crossrail Information Paper D9, Noise and Vibration
Mitigation Scheme (LINEWD-IPD9-001). Back
7
Crossrail Information Paper D9, Noise and Vibration Mitigation
Scheme (LINEWD-IPD9-002-005). Back
8
Crossrail Information Paper F5, Complaints Commissioner (LINEWD-IPF5-001). Back
9
Crossrail Ref: P70, Plan & Map of Hunter Avenue, Alexander
Lane, Herrington Grove, Mount Avenue & Pine Croft (Location
of Petitioners) (BRWDBO-14903-008). Back
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