Examination of Witnesses (Questions 12160
- 12179)
12160. The Chairman: So it is not you!
12161. Mr Cameron: So it includes those
measures—and tell me if I should not ask you this—and
on a practicality, if I am the contractor working on the site
I have to decide which measures are appropriate for that site
at a particular time; have I understood that correctly?
(Mr Ireland) That is correct.
12162. How, without some kind of baseline information,
without monitoring, can an independent observer tell whether the
measures taken have been effective or not?
(Mr Ireland) First of all, the mitigation measures
available will have been agreed with the local authority; the
mitigation measures available would have been matched against
the construction programme, let us say, for the following month,
and that would have been agreed, and consultation with the local
authority. Therefore, whether the mitigation measures have been
effective would be assessed by whether they had been applied correctly
and appropriately
12163. Mr Ireland, that is all very well and
good but if I am worried about my theoretical Mrs Jones, who lives
up the road, and she makes a complaint to the local authority,
"I am suffering from dust," how can either the local
authority or the contractor tell whether the measures that the
contractor has chosen to take have been effective? It is all very
well saying that you have done what you said you would do, but
how do you check that it actually worked?
(Mr Ireland) Because there will be a documented
procedure for site inspection and recording of the observations
made by the responsible person.
12164. That all sounds very good, but can I
just have an answer to my question? How can you tell whether the
contractor's choice of measures adopted has been effective or
not for those living, working and children playing off the site?
(Mr Ireland) The application of dust mitigation
measures would have been agreed with the local authority. The
mitigation measures that we have identified would have been considered
comprehensive and would actually not result in impacts on Mrs
Jones, as in the photo here, and really it is a question of making
sure that those mitigation measures were applied properly rather
than assuming that there is going to be an impact.
12165. I think the answer to the question is
that you cannot tell, can you? Without monitoring you cannot tell
whether the steps chosen by the contractor have been effective
or not; is that a fair summary of your answer?
(Mr Ireland) That is a fair summary, but I
would easily argue that monitoring does not tell you whether there
has been an impact on Mrs Jones' property. That could be related
directly to a specific activity such as the construction works
that we are referring to here. It could easily be the result of
other activity. As I referred to in previous evidence given here,
it could be the result of a dust storm in the Sahara that has
led to the incident at Mrs Jones's property.
12166. In terms of the practical difficulties
that you raise about baseline monitoring, if your arguments were
accepted it would apply to any construction project anywhere in
London and you could never carry out baseline monitoring because
of the uncertainties that you referred to.
(Mr Ireland) There are examples of major construction
sites in the UK where the type of dust monitoring that we have
proposed here, ie. based on site inspection and measured by monitoring
the application techniques rather than measuring dust per se—there
are examples of the application technique in the UK.
12167. And there are examples of baseline monitoring
in the UK, are there not, and I give you the example of Kensal
Green gasworks site, which is right within window W2, and the
short point is that if it can be done for that why can you not
do it?
(Mr Ireland) I would argue that if it can be
done without dust monitoring, why can it not be done without dust
monitoring?
12168. In terms of the approach that you are
recommending, can I ask you about the GLA Draft Good Practice
Guidance, page 39?[49]
I fully acknowledge that this is draft guidance, "If best
practicable means identified in Sections 4 and 5 are followed
correctly, then formation of dust and harmful emissions from construction
sites should be minimised as much as possible," and that
is your point, is it not? If the measures are adopted you should
minimise the effect?
(Mr Ireland) That is right.
12169. What the guidance goes on to say is,
"However, continuous site monitoring is still an important
way of helping contractors manage dust and PM10 emissions from
construction and demolition. This section specifies monitoring
protocols that should be followed according to the identified
risk of the site." And the simple point is: why will Crossrail
not follow this good practice guidance?
(Mr Ireland) I would argue that if the first
point is adhered to then the second point is redundant. Working
with contractors, they would rather apply proper management techniques
to control the issues at source rather than dealing with issues
outside the site which has uncertainty attached to it. As I said
earlier, there are examples where contractors at major construction
sites in the UK have limited their management to measurements
of monitoring the application of techniques within the site, and
that has been sufficient.
12170. So you disagree with the guidance and
you will not recommend to Crossrail that they follow it; is that
right?
(Mr Ireland) I believe that the first point
made in the guidance is sufficient.
12171. In terms of practice followed on other
sites, if the Docklands Light Railway can manage to enter into
a protocol with the local authority, which includes the document
we put in—it does not have a number, and I do not think
it needs one. Do you have that document that we put in this morning?
(Mr Ireland) No, I do not.
12172. It is A133, page 19.[50]
This is a Code of Construction Practice, revised as recently as
February 2006, the Docklands Light Railway Extension, and there
it requires, at the top of page 19, that, "The contractor
shall propose and agree with the local authority a protocol, which
includes everything that the borough are asking for, baseline
monitoring, trigger levels and arrangements for monitoring, analysis
and reporting of dust, and handling public reports of incidents
and complaint." So if they can agree to it it indicates that
they disagree with you that it is impracticable, do you agree?
(Mr Ireland) Taking a scientific
analysis, I would argue points 1 to 3, but clearly bullet point
4 is using techniques and practices that are available and readily
used at present.
12173. But in terms of a procedure this demonstrates
practicality, and again the question is: why will you not recommend
to Crossrail that they follow the practice followed by the Docklands
Light Railway?
(Mr Ireland) Because personal experience of
working on construction sites and working on, if you like, on
both sides to the fences, the setting of trigger levels firstly
is very difficult. Agreement on a monitoring technique, which
is both robust and reliable, is also difficult and what generally
happens is that more time is spent arguing over the results and
whether the data are robust or not, than actually managing the
problem, and in my mind it is far best to focus resources and
time and focusing on managing the problem when it arises rather
than wasting effort on arguing other matters.
12174. I think you say to concentrate on the
management of the problem that we are back to where we started,
how can the local authority or other body which receives complaints
concentrate on the management of the problem if they have no data
upon which to act?
(Mr Ireland) I refer again to the documentation
of the site inspections that would be available as made by the
contractor.
12175. In terms of techniques or equipment you
made some comments about the capabilities of the light scatter
device. You do not foresee, do you, any difficulties in managing
dust deposition rates; your criticism relates to monitoring poor
health effects, is that right?
(Mr Ireland) The monitoring of suspended particulates—this
is the particulate matter that we breathe—the monitoring
methods are actually more robust than they are for the measurement
of dust emission. There are a number of techniques which have
been proposed for the measurement of dust deposition. We referred
earlier to the inverted Frisbee; there is also the glass light
technique, which was actually developed within London, and there
is the sticky pad technique. Each of those techniques has limitations,
mainly to do with practical limitations of installation of the
equipment, and each of them is prone to very wide margins of error,
and as such I would argue are not sufficiently reliable as a method
of monitoring.
12176. My last point. If you and Crossrail had
concerns about the nature of the equipment to be used, the undertaking
proposed by the borough would allow you to express those concerns
because the methodology to be adopted is to be agreed. So the
suggestion of a light scattering device is not a reason to fail
to enter into discussions, is it?
(Mr Ireland) If we talk about particulate matter
as a health matter to begin with, there are significant monitoring
efforts undertaken within London and indeed the UK as a whole,
looking at PM10 and indeed PM2.5. What we have to remember is
that the health impact of particles increases as the particle
size reduces, but also as the particle size reduces the atmospheric
chemistry element of the particulate matter becomes more important.
Therefore, the source of the particulates becomes more widespread.
So what happens, as the particle size becomes smaller the localised
effect is much less reduced, and we tend to get much more smearing
of particulate concentration across a wider area. There is significant
monitoring of PM10 across the UK, and I would argue that that
is sufficient for the purposes of air quality management. With
regard to larger particulates, the light scattering technique
has not been proven and my understanding in discussions with manufacturers
of such devices over the years is that they do not work well in
environments with different types of particulates—particulates
from diesel engines, from traffic or from construction sites.
Once you have a heterogeneous mixture of particulates the effectiveness
of a light scattering device is significantly reduced.
12177. But going back to the question, if you
have concerns about the equipment to be used you can specify other
equipment and agree it with the local authority, do you agree?
(Mr Ireland) No, because I am not aware of
any equipment which is available of sufficient robustness that
it would be valuable beyond the site inspection monitoring techniques
that have been proposed.
12178. So what type of equipment would be used
by your people if Tier 3 is adopted and monitoring takes place
on site?
(Mr Ireland) In one particular example we have
referred to using a TEOM and that was related to the Smithfield
Market, where there were concerns with the food handling aspects
of particulates.
12179. Tier 3: that is going to be monitoring
onsite. A simple question: what equipment will be used?
(Mr Ireland) No specific equipment is referred
to; it will be the site inspection records that would be available.
49 Committee Ref: A132, Existing Good Practice-Best
Practice Guidance: Extracts from the GLA Code of Practice (KENSRB-31405-040). Back
50
Committee Ref: A133, Code of Construction Practice for the Docklands
Light Railway extension, p19 (SCN-20060622-001). Back
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