Examination of Witnesses (Questions 6580
- 6599)
6580. Is there residential accommodation in
this area?
(Mr Griffiths): There is, yes.
6581. Diamond sawing, can you just explain to
me what that is?
(Mr Griffiths): That would be like a circular
type saw and that can cut through concrete bricks and so on.
6582. Is it a nice quiet operation?
(Mr Griffiths): It is a very noisy operation.
6583. And is this usually in addition to a hydraulic
breaker or in substitution for it?
(Mr Griffiths): This would be in addition to
the hydraulic breaker, this would cut/sever the two buildings.
6584. We have something that has been brought
in now which is in addition to it and what are its vibration levels
then?
(Mr Griffiths): Its vibration levels are quite
low, but it is making the noise of a diamond saw.
6585. Can you give the Committee an idea of
the noise that is being promoted?
(Mr Griffiths): Probably 10 metres, which is
a standard yardstick, it would be at least 90 decibels and again
I would have to look that up, but you are sawing into concrete
or brick. I think anyone who does any D-I-Y with hand tools will
know the sort of level that you can get out of that.
6586. Does 13-17 have double glazing?
(Mr Griffiths): This is the second building?
I think it does have double glazing, but it is thermal glazing,
it is the narrower gap.
6587. I am told that it does not, but that is
a matter of fact.
(Mr Griffiths): I think part of it does have
double glazing.
6588. And these offers that were being raised
with you in relation to the undertaking. Are we anywhere closer
to having a design standard to aid that in relation to vibration?
(Mr Griffiths): No, I am not aware of any standard
which, as I say, has to pose a risk to my client.
6589. Why is there this approach, in every other
area that I have heard in my attendance here, design levels are
being suggested, but in vibration none is being suggested, why
is that?
(Mr Griffiths): I really do not know. I mean
when someone is predicting levels one and a half to seven millimetres
per second, if you are really talking about seven millimetres
per second people would be very, very frightened and to not have
a standard when you are predicting those sort of levels, I think
anyone would accept if you have got levels of seven millimetres
per second no one in this room would be here. As I say it is a
very frightening experience at that sort of level, so I am surprised
there is not a value being installed for offices.
The witness withdrew
6590. Mr Taylor: Sir, I have got Mr Thornely-Taylor
here who can give evidence reflecting the points I have put in
cross-examination if you would find that of assistance.
6591. Chairman: I think, Mr Taylor, we
have heard such evidence before and I do not think there is any
need to recall in that respect and I think we have heard enough
today to cover noise to get a view on it.
6592. Mr Taylor: In closing, can I just
say a few words? We say that Mintel is not a particularly noise
sensitive user. The levels of noise within their premises is similar
to any office base use and in terms of being accepted as a special
case because of the particular proximity of the Lindsey Street
work site and the substandard nature of the attenuation provided
by the premises, the Promoters offered an appropriate undertaking
to carry out the works in a manner that will mitigate the influence
of noise and vibration as far as reasonably practicable. It has
offered a noise and vibration mitigation act which, based upon
limits which would be identified, taking into account a number
of factors, a mitigation act which can be identified which will
ensure that the noise and vibration from the construction will
not significantly affect the business operation of the premises.
There are a number of mitigation techniques available that will
ensure that airborne noise will not cause significant problems,
for example, with the potential use of secondary glazing.
6593. When it comes to vibration it is piling
and demolition work that is of particular concern, but the total
duration of piling has been identified six weeks and I mention
that on instructions. It is proposed to used oscillatory bore
piling. This is a low vibration technique. With that piling technique
significant vibration acts upon the Petitioner's property are
unlikely. It is the use of the hydraulic breaker that is of particular
concern in relation to vibration. This activity would only occur
at the points closest to the Petitioner's property for a period
of some two to three weeks in total, and again I put that figure
on instructions. It may be possible to use alternative methods
of demolition, for example, a cruncher to reduce this period significantly,
but make it possible to limit vibration caused or emitted during
particular hours of the day. It may be that works could be done
to reduce the structural interface between the work site and the
building.
6594. It is not appropriate at this stage to
identify specific noise or vibration limits to apply at the Petitioner's
property, these should be identified at the detailed design stage.
In any event, these take into account a number of factors that
are unknown at present, such as the particular use of particular
rooms and the attenuation provided by the building within those
rooms. Nor is it appropriate to identify the particular mitigation
that needs to be adopted at this stage. The proposed undertaking
will give rise to a dispute, a solution procedure will be invoked
if it is unhappy with the measures adopted.
6595. As far as dust is concerned, the premises
are already fully air conditioned, tier three dust mitigation
is proposed for the Lindsey Street work site due to the proximity
of the Smithfield Market. That involves the provision of a high
standard of dust control needs to be achievable.
6596. So far as access is concerned, the policy
with regard to retaining access during construction is set out
in IPC7.[64]
The Bill contains a requirement to ensure that pedestrians have
a reasonable access to any premises affected by the interference
with the highway and that is C7, paragraph 1.43, schedule 3, paragraph
5 of the Bill. Paragraph 2.2 provides that a reasonable level
of access will be maintained for both vehicles and pedestrians.
The undertaking offered reflects this policy. The works affecting
Hayne Street is to retain access to the car parks so far as practicable
and again I am putting that on instructions.
6597. As far as power supply is concerned, the
policy regarding maintenance of public utilities during construction
is set out in information paper D7.[65]
The construction arrangements have been designed to keep disruption
to as low a level as reasonably practicable, that is in information
paper D7 paragraph 1.3. The undertaking offered does this. Indeed,
bearing in mind that the Mintel Company has no guarantee of uninterrupted
power and has arrangements in place to cater for this.
6598. In conclusion these undertakings will
be sufficient to ensure that an appropriate environment can be
retained during the construction activity that will enable the
business to continue and there is no reasonable basis for requiring
the Promoter to fund the permanent re-location.
6599. Mr Newberry: I would ask you to
conclude that this is an operation which is a sensitive operation
in terms of having to undertake detailed and painstaking research
and therefore requires the appropriate environment. I therefore
would ask you to conclude that it is such.
64 Crossrail Information Paper C7 Access to Residential
and Commercial Property during Construction, http://billdocuments.crossrail.co.uk Back
65
Crossrail Information Paper D7 Maintenance of Public Utilities,
http://billdocuments.crossrail.co.uk Back
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