080731 6LYG A1 Particular Tunnelling Specification ... - SCATnow

Lee Tunnel, Contract No. 6LYG/A1
PT – Particular Tunnelling Specification - PT200
PT209.5
PT210
PT210.1
PT210.2
PT210.3
PT210.4
PT210.5
PT211
PT211.1
g) An adjustable copy cutter with means of detecting the stroke and the arc
through which it is selected.
The Contractor shall consider in the design of the TBM a means of ensuring a
safe method of work for the personnel carrying out all necessary work on the
cutter head including mechanical aids for the transport of tools and equipment
into the cutter head.
CUTTER HEAD INTERVENTIONS
The Contractor shall submit within 28 days of the award of Contract a Method
Statement detailing the proposed method for cutter head interventions for
planned and unplanned maintenance, head inspections and other events. Should
the use of the TBM compressed air system be considered the Method Statement
shall demonstrate compliance with following compressed air documents:
a) Work in Compressed Air Regulations (1996).
b) Health and Safety Booklet “A Guide to the Work in Compressed Air
Regulations 1996 – Guidance on Regulations (L96).
c) Addendum “A guide to the Work in Compressed Air Regulations 1996 –
Guidance on Oxygen Compression and use of Breathing Mixtures other than
Compressed Natural Air in the Working Chamber” issued by the Health and
Safety Executive.
The Health and Safety Executive have advised the Employer that whilst the
Regulations are not being revised, a new document combining references b) and
c) above, along with a revision of the combined text is in preparation and it is
hoped that this document will be issued by the HSE before the proposed start
date of this Project. It is understood that the HSE document will set out
procedures requirements on the Contractor seeking exemptions from the
Regulations and for the approval by the HSE of the compressed air working
practices which deviate from those required by the regulations. These could
include interventions at pressures greater than the present legal pressure limit of
3.5Bar. With this understanding, it will be the intention of the Employer to hold
discussions with the Contractor to assess and agree what impact these changes
will have on the Contractors proposed methodology for interventions at high
pressures, its impact on the proposed programmes and cost implications. The
Contractor shall, in order to mitigate any potential delays to the Project and to
ensure the cooperation and assistance in obtaining required approval from the
Health and Safety Executive, invite a representative of the HSE to attend any
discussions held on the issue of working in Hyperbaric Conditions. Preliminary
discussions will be held between the Employer and the HSE in advance the
award of Contract to try and secure HSE’s agreement in principle to interventions
at pressure in excess of 3.5Bar.
The Contractor will be responsible for obtaining all Regulatory exemptions and/or
approvals for the proposed methodology and the Project Manager shall be invited
to attend any meetings held with the Health and Safety Executive (with a
minimum of two weeks notice).
The design of airlocks shall conform to BSEN 12110:2002 Tunnelling Machines-
Air-Locks Safety Requirements (currently being revised).
The design shall include an effective means of testing for and purging the forward
chamber of any hazardous gases and ventilating the TBM and back up before
entry.
FRONT SHIELD
The Front Shield shall incorporate a pressure bulkhead designed to withstand all
operational pressures.
Thames Water Utilities Limited August 2008
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