Firoz Lalji Global Hub - Impact of Works

What is noise?

Sound is what we hear—noise is unwanted sound. The difference between sound and noise depends on the listener and the circumstances. The picture in Image 1 shows the sound scale in decibel (abbreviated "dB") relative to common sounds.

What is the Decibel range adopted for the (FLGH) noise assessment?

The criteria adopted for the technical assessment of potential noise impacts of FLGH are set out in the table below. If the technical assessment identified a potential impact over the range then a possible noise problem could arise. See Table 1

Does different glazing make a difference?

The type of window will make a great deal of difference to the impact of noise (assuming it is kept shut) This is why we have surveyed windows which might be effected by the FLGH works. Estimates of noise reductions for different types of windows are in Table 2 below

What are the survey findings and next steps?

We are undertaking an acoustic model to determined the likely noise levels at the facades of all the surrounding buildings, taking into account the type of windows in each room and using the Decibel ranges set out in Table 1 above. The report should make recommendations for relevant mitigation proposals in rooms where the anticipated noise problems could occur. We will update further in future newsletters and meetings.

What is dust?

Throughout the demolition and construction period, it is likely that dust will be created.

Construction Dust is a general term used for what may be found on a construction site. Silica is the main type of dust, it is a natural mineral present in large amounts in things like sand, sandstone and granite. It is also commonly found in many construction materials such as concrete and mortar.

Dust Monitoring and Control

The demolition contractor is required under the Construction Code of Practice (CCoP) published by Westminster City Council to undertake real time dust monitoring throughout the duration of the contract. The CCoP requires the contractor to use a dust monitoring system which uses data logging dust meters at up to 10 pre agreed locations within adjacent occupied space. Data will be accessed remotely and recorded ‘real-time’ through an accessible online portal that will alert registered users when the following exceedance levels are met.

Amber – Particulate Matters (PM10) 40 µg/m3

Red – Particulate Matters (PM10) 50 µg/m3

The mitigating actions will be:

Amber - continue work but investigate the cause of the exceedance and put in place further mitigation measures and advise the client and its representatives of the action undertaken.

Red - cease work, investigate the cause and put in place further mitigation measures and advise the client and its representatives of the action undertaken and obtain agreement before re-commencing activities.
The contractor will be responsible for the implications of any stoppages.

The Employer reserves the right to terminate the contract for failure to adequately address Red exceedances on more than 3 consecutive occasions from any individual source of dust during construction.

Proposed Monitoring Locations

The proposed dust monitoring locations will be subject to an assessment on site by monitoring professionals to identify the practicality of the proposed locations.

Locations have been proposed keeping in mind the prevailing wind direction, and the height, location and proximity of sensitive receptors.

Proposed monitoring locations were selected based on the following:

DMP1 – Located upwind of the prevailing wind direction on the site boundary, along Lincoln’s Inn Fields. Close to residential receptors.

DMP2 – Located downwind of the prevailing wind direction on the site boundary, along Portugal Street. Close to residential receptors.

What is structural borne sound?

According to the British Regulations Approved Document E, structure-borne sound is defined as ‘sound that is carried via the structure of a building’. For example, the noise of demolition in the basement of a building may be heard in adjacent buildings and is classified as structure-borne sound.

Structural borne vibration can be a serious concern for any building or structure within or adjacent to a construction zone. These structures may be potentially impacted by vibrations emanating from construction activities such as demolition, compaction, excavation, blasting, pile-driving, and operating heavy earth-moving equipment. In extreme cases, the vibration can cause damage to adjacent buildings and create discomfort and annoyance for building occupants.

Vibration is normal and is an expected consequence of demolition. However, staff and students in buildings surrounding the Firoz Lalji Global Hub site may feel vibration and comment on it and be concerned. Any vibration will be monitored and measured to ensure it is within expected and normal limits.

Typical vibration monitor

During the demolition period the contractor (Deconstruct) will be setting up vibration monitors to monitor adherence to British Standards and to Westminster City Council prescribed limits. The monitors will indicate to the contractor when vibration is close to the limits so they can change the method of demolition accordingly.

Soft Demolition: Internal works to strip out the building with recycling of some materials and safe disposal of others including asbestos. This work has minimal impact on surrounding buildings although vehicle movements may increase. – completion May 2024

Planning approval will be finalised 21 May 2024.

Hard Demolition: Following the planning approval the hard demolition will commence. This is the breaking up and removal of the building structure down to basement level. Noise and dust mitigation measures will be completed prior to the start of this element of the work which has the potential to be disruptive to neighbours. 

Scaffold protection screens will be installed to the front elevation from level 5 upwards of 35 Lincoln’s Inn Fields, full height to the rear, full height to the east elevation and full height around the perimeter of the lightwells. A full height scaffold and noise screen will be installed to the west elevation of the Sir Arthur Lewis Building adjacent to 35 Lincoln’s Inn Fields.

The contractor’s stipulated working hours are :

Between 08:00 and 18:00 Monday to Friday

Between 08:00 and 13:00 on Saturday

No work will be undertaken outside the stipulated core hours on weekdays or Saturdays, and no work is to be undertaken on Sundays and Bank holidays, without prior arrangement with the LSE and sanctioned by the Environmental Health Officer. This may be granted for certain operations which are influenced by other factors e.g. tower crane erection requiring road closures or transport escorts as dictated by the Police, concrete pours that need to be completed and fitting out work within buildings.

A tower crane will be installed on site in June 2024 which will likely include a road closure to part of Lincoln’s Inn Fields, communications and a detailed plan of any road closures will be sent out once the dates have been confirmed. 

The bar chart in Table 1 shows the demolition phase taking approximately 34 weeks i.e. approximately 9 months.

There are several stages to the demolition works which will have differing impacts on the School.  These are summarised in table 2 below.