Environmental monitoring

We will keep this page regularly updated with information from our environmental monitoring tests. We carry out these tests regularly on noise, dust and vibration levels and air quality to ensure that we understand the effects of our work on the local environment.

Vibration Monitoring

Ground vibration monitoring has been carried out at the Clarendon Road Gasworks site throughout the demolition and site enabling works.

Ground vibration is measured by calculating the peak particle velocity (PPV) – the movement of molecular particles within the ground - in millimetres per second (mm/s). Industry standards dictate that a PPV of up to 10mm/s is acceptable and safe for a site of this nature.

As the data demonstrates, on the vast majority of working days since February 2017, vibration on site has been well below the maximum limit, with the exception of March 6th 2017 when an excavator breaking down a brick structure within ten metres of the Vibrock monitor resulted in PPV of 11.7 mm/s.

Click here to view the vibration monitoring data since January 2017

Asbestos Monitoring

In May 2017 we wrote to our neighbours to inform them we had temporarily stopped remediation work at the Clarendon Road Gasworks site after identifying the presence of asbestos in the infilled tank of a former gasholder.

We’d like to reassure residents that all work carried out before and after this discovery has been undertaken in a carefully managed and controlled manner to ensure there’s no risk to health. Regular monitoring has been carried out to confirm this.

After consulting with Haringey Council and informing the HSE and Environment Agency, we removed the safely contained stockpile of material that was excavated from the gasholder tank under controlled conditions, using a specialist asbestos removal contractor.

After the stockpile was removed, we also removed more material from deeper within the gasholder tank to make sure asbestos couldn’t be a risk to future construction workers or residents. Again, this was done under controlled conditions using a specialist contractor. The majority of asbestos material has now been completely removed from site, with the remainder safely capped and sealed within the deepest portion of the gasholder tank.

Results of the regular monitoring carried out on site show the level of fibres found in the air around the site has been consistently below the HSE clearance limit threshold of 0.01 fibres per millilitre.

If you have any further questions about this issue, please get in touch with our community relations team using this contact details provided.

Handheld Noise Monitoring

Hand held noise monitoring was also carried out during demolition and data results undertaken by Coleman and Company from 9th January 2017 to 15th March 2017. Low / peak results are given in the below table.

Noise Monitoring

We have undertaken several rounds of noise monitoring over the past few months, during work to dismantle the Gas Holders. The table below shows the data we recorded.

Background Monitoring

The table below shows the noise levels that were recorded during background noise monitoring in January 2016. This gives us baseline noise levels. Baseline levels can be described as the usual level of noise experienced at a location. Comparing our works to a baseline allows us to tell the impact we’re having. The map shows the locations where measurements were taken.

To give these figures some context, the table below shows the typical noise levels of the types of sounds which were recorded during the background monitoring.