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Next Monday the most famous clock bell in the world will stop chiming to protect workers from its loud noise during restoration work. SHP assesses the case.
Although national news stories have inevitably focused on the fact the 156-year old structure even ‘kept chiming during WW2 and the Blitz’, this is not the first time the bells have fallen silent. And it happens fairly regularly, as birds, faults and other issues have meant workers need to get it going again.
But in terms of long-term silent periods, this has happened before. The bell did not chime for a period of around nine months when the clock underwent a major overhaul in 1976. Significant conservation work was carried out between 1983 and 1985, and it was silenced for a time during this period.
The previous periods of silence were not to protect workers’ hearing though. This makes the current restoration project unique.
So how loud is Big Ben? The answer is, unsurprisingly, very loud.
Big Ben’s chimes have been measured at 118 decibels. This makes it louder than a hammer drill and the majority of regularly used construction and industrial equipment (see graph).
Official guidance by the Health and Safety Executive states any regular exposure of more than a minute to sounds in excess of 110 decibels would cause permanent hearing loss. Big Ben easily falls into this category.
The level at which employers must provide hearing protection and hearing protection zones is now 85 decibels (daily or weekly average exposure) and the level at which employers must assess the risk to workers’ health and provide them with information and training is now 80 decibels.
There is also an exposure limit value of 87 decibels, taking account of any reduction in exposure provided by hearing protection, above which workers must not be exposed.
Indeed, a spokesperson for the parliamentary authorities said the chimes were being stopped to provide a safe environment for the workers that will be on scaffolding.
Constant proximity to the chimes would ‘pose a serious risk to their hearing, and prevent efficient working’, they said.
But can’t the workers just wear ear defenders?
There are probably are fair number of readers that are thinking: ‘Why not just buy some PPE and get the team to wear ear defenders on site?’
Well, this question has indeed been answered by the restoration team.
A spokesperson for the work told the Evening Standardthat clock mechanics who work on Big Ben currently get ear defenders, but are exposed to the ringing bells for only short periods of time each week.
“People will be working on the scaffolding day-in day-out throughout the works, and, while protective headgear could be provided, it is not desirable for individuals working at height to have their hearing obscured as there is concern the ability to hear each other and any alarms could be affected.”
Assessing noise levels like Big Ben? See this flowchart:
When exactly does Big Ben stop – and for how long?
On Monday 21 August 2017 following the 12 noon chimes Big Ben’s bongs will temporarily cease.
The Great Bell’s striking and chiming will be paused until 2021 to ensure the prolonged safety of those working on the project.
Parliament’s specialist clock mechanics will ensure that Big Ben can still bong for important national events such as New Year’s Eve and Remembrance Sunday.
Visitors and safety
There is also a fire safety angle and health and safety for visitors to the works on Big Ben.
The tower ‘needs to be brought in line with fire prevention guidance, and health and safety measures for staff and visitors need to be improved’, the authorities said.
In order to provide a better means of emergency evacuation, and to improve accessibility for a wider range of people, a lift will also be installed within the existing ventilation shaft of the Tower.
A recently conducted feasibility study of the Tower has shown that this work cannot be delayed until the larger scale regeneration project due to begin in the 2020s, and as the Tower has not been extensively renovated for over 30 years, it now requires ‘urgent attention’.
The Regulatory Reform Order (fire safety) 2005 (RRO) requires Parliament to comply with current fire safety requirements by 2018. At present, the Elizabeth Tower is not compliant, and alterations must be made to meet these requirements.
There are also a number of workplace health and safety risks which must be addressed in order to ensure the safety of those working in the Tower and visitors. This includes implementing a solution to ensure that in the event of an emergency, a casualty could be evacuated from the Tower as quickly as possible.
Three-year programme of works
The move is part of a £29m three-year programme of essential works to conserve the Elizabeth Tower, the Great Clock and the Great Bell, also known as Big Ben are due to begin early 2017.
As the Tower is 96 metres tall, scaffolding is needed to enable workers to reach high levels safely. Scaffolding will be dismantled as the work is completed from the top, and at least one clock face will be on show at all times.
Works will include:
Repair problems which cannot be rectified whilst the clock is in action
Conserve significant elements of the Tower
Repair and redecorate the interior, renew the building services and carry out work to improve health and safety and fire prevention
Increase energy efficiency to reduce the Tower’s environmental impact
Rt Hon Tom Brake MP, Spokesperson for the House of Commons Commission, said: “The Elizabeth Tower is a symbol of the UK’s democratic heritage and forms part of a UNESCO World Heritage Site.
“We have a duty to ensure that it is safeguarded for future generations to appreciate, just as we owe it to our predecessors to restore their masterpiece to its former glory. While these works are much needed in the short-term, they will also ensure the long-term future and sustainability of Big Ben.”
Steve Jaggs, Keeper of the Clock, said: “This historic clock is loved by so many people. It is both an honour and a great responsibility to keep it in good working order for public enjoyment. Every day our team of highly skilled clock mechanics cares for this Victorian masterpiece but, in order to keep the Clock ticking, we must now take the time to thoroughly inspect and restore it.
“These essential works balance value for money with Parliament’s custodial responsibility to the building as well as to those visiting and working in the Elizabeth Tower. This project will enable us to give one of Britain’s most famous landmarks the TLC it so desperately needs and deserves.”