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 below (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 1 below. If the technical assessment identified a potential impact over the range then a possible noise problem could arise.

What governs noise levels and how will it effect SAL?

Westminster City Council (WCC) is the local authority covering the majority of the LSE campus. WCC operates a Code of Construction Practice (CoCP) to monitor, control, manage and enforce its statutory duties for major development sites and this will include the Firoz Lalji Global Hub Redevelopment project.

The CoCP sets out standards and procedures for managing the environmental impacts during the construction of major projects. It covers the environmental, public health and safety aspects of the project that may effect the interests of local residents, businesses, the general public, and the surroundings of the proposed construction site.

The CoCP covers a number of aspects of construction including hours of operation, noise, dust, and traffic movements setting out the legislative framework covering all these issues under which WCC operate. WCC will impose a CoCP on the LSE as a a condition of the planning process, or by prior agreement.

Once the final part of the planning permission has been approved by Westminster WCC (May 2024), the resuse/demolition contractor will start to remove the wall joining 35 Lincolns Inn Field facing the Sir Arthur Lewis Building. This is to allow space for a crane to be erected in the centre of the building. The demolition of the external wall will see an increase in the noise levels in the surrounding area.

Noise Control in SAL Building

In order to mitigate against additional noise levels, contractors will install a Monarflex sheeting (image 2), as well as an acoustic quilt (Soundex) behind the Monarflex which will be moved down the building as the demolition progresses. The Soundtex quilt can reduce the transfer of noise by up to 28.2 dB allowing staff and students in the surrounding in the surrounding building to continue their day-to-day activities.

The Estates team also commissioned a survey within the SAL building to assess the effect of the noise from the demolition on individual teaching rooms. It was found that teaching and studying windows on the West elevation of the building (facing 35 LIF) are fitted with secondary glazing which will reduce the impact of the airborne transfer of noise caused by the demolition works.

The table 2 below illustrates the reduction in noise levels from different types of window treatment will have on external noise. The contractor will be taking noise measurements in surrounding buildings during particularly noisy activities to ensure the dB levels are within agreed parameters.

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.

Dust Control in SAL Building

In order to mitigate against the effects of the increased dust levels the contractor will be wrapping the building in a Monarflex plastic sheeting (see image 2), which will not only give protection to the contractors operatives by allowing work to progress in all weather conditions, but also reduce noise and dust caused by the demolition works.

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.

Road closures

A tower crane is due to be installed to the east lightwell of 35 Lincoln’s Inn (elevation facing the Sir Arthur Lewis Building, SAL) on the weekend of 8 – 9 June 2024 which will include a road closure to part of Lincoln Inn Fields. The following map illustrates the extent of the roads and parking bays that will be affected during the erection of the tower crane. Notices have been posted on lampposts in the area advising of the road closures.

Once installed the tower crane will remain in position for the remainder of the demolition period and for the duration of the construction phase of the building.

Below is a description of the nature of road closures, their start and end time.

Hard Demolition

From week commencing 3 June 2024 until December 2024 the hard demolition phase of the project will commence. This phase involves the partial breaking up and removal of the building structure down to basement level. This means that noise levels will increase during working hours.

Noise and dust mitigation measures will be implemented prior to the start of this element of the work to mitigate and minimise any potential disruption to students, staff and neighbours during the works.

Scaffold protection screens and have been installed full height to the west elevation of the Sir Arthur Lewis Building adjacent to 35 Lincoln’s Inn Fields. Additional movable sound quilts which will help reduce noise levels have been installed around the working area and will move down the building as the working area progresses.

The works will be carried out in accordance with WCC’s Construction Code of Practice (CCoP) which limit noisy works to be carried out:

Between 8am and 6pm Monday to Friday

Between 8am and 1pm on Saturday

No work is to be undertaken on Sundays or Bank holidays, without prior arrangement with the LSE and sanctioned by the Environmental Health Officer. Further to these working parameters imposed by WCC, the Contractor has agreed to avoid carrying out the noisiest activities between 10am and 12:00 and again between 2pm and 4pm.

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. 

Find details of the planned works from December 2024 - February 2025 (pdf)

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.