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Changing tunnellers' shift patterns

35507 crossrail western tunnels

What impact do changing shift patterns have on the health, safety and fatigue of workers on tunnelling projects?

With major tunnelling projects such as Crossrail and Scottish Water’s Shieldhall Tunnel concluding and others such as High Speed 2 (HS2) on the horizon, there is a debate about how best to manage workers’ time?

In the tunnelling industry, the argument to move to three, eight hour shift patterns, as opposed to the current industry norm of two, 12 hour shifts, is not as straightforward as it may seem.

The primary reason given for the change is to protect the workforce. The view among many in the industry is that 12 hours is too long to sustain the physically and mentally demanding job of tunnelling work.

Tiring long shifts

Towards the end of a long shift, fatigue can creep in, increasing the chances of an accident. But at the moment this is only an opinion as there is insufficient data to back it up.

New Civil Engineer has spoken to, a mix of clients, contractors and researchers and they broadly agree that a move to working eight hours instead of 12 would be a positive step. But each had their own concerns or caveats.

A poll conducted by New Civil Engineer  at its recent Tunnelling Summit showed that 42% of the industry favours the move.

However, research shows that introducing eight hour shifts can contribute to worker fatigue, if shift patterns are rotated between morning, afternoon and night.

When you rotate around an eight hour shift pattern, mornings, afternoons and evenings, there are problems with that

Employers say they have been talking about fatigue for quite some time and some have come to the conclusion that fatigue is not the issue, so much as the changes in shift patterns. This in turn leads to the difficult subject of circadian rhythms.

“We’re really only at the early stages on recording this more accurately,” says Crossrail safety director Martin Brown.

There are many ways in which shift patterns can be put together and how they can be regulated.

Consecutive days

The issues concern the number of consecutive nights or days that are timetabled, and how much time off should be given for recovery.

Other variables such as the location of a project can also have an impact. In cities, there is more for workers to do during their time off. How time off is spent when working close to or away from family or friends can also be a factor.

In  France and Germany there are defined limits on how many hours which can be worked in a month.

Although research has been conducted in other sectors such as the military and aviation, findings cannot necessarily be applied  directly to tunnelling.

Research has been conducted in other sectors such as the military and aviation, findings cannot necessarily be applied  directly to tunnelling.

Tideway is one client which has made the move to mandating shorter working hours, but it has stopped short of specifying eight-hour shifts.

Instead it stipulates that workers must not spend more than 10 hours underground and that a copy of the contractor’s fatigue management plan be made available to ensure measures are in place to prevent workers becoming over-tired.

Tideway asset management director Roger Bailey says that when this is done, shift patterns, which can also impact on fatigue, can be taken into account.

‘Wrong to work 12 hours’

“We looked at this four to five years ago and we said by inspection that it’s wrong to work 12 hours, but it’s not as simple as replacing it with three times eight hours,” says Bailey.

“What we should be saying is: ‘you can’t do more than 10 hours and we want to see your fatigue management plan’, because the shift patterns, whether it’s five shifts and two days off or seven shifts, are relevant too.

“It’s a whole piece.”

He disagrees with the view that it should be up to clients to specify eight hour shifts. “Otherwise you end up telling the contractors and specialists how to do their job,” he says.

More research needed

Contractor Bam Nuttall has switched to three, eight hour shifts for some of its tunnelling jobs, and is looking at how the move is affecting accident and productivity rates.  Divisional director for major projects John Heffernan applauds Tideway for taking the step towards changing attitudes.

But he also agrees that more research to find optimum work patterns is needed.  

One issue which comes up repeatedly is how time spent outside work affects worker fatigue.

Reducing shift times from 12 to eight hours is only beneficial if workers use that time for restful activities. Or as one engineer who asked not to be named said: “If workers spend the four hours down the pub because they have nothing else to do, then they might be just as fatigued as they were otherwise”.

Influencing leisure time

But as Brown points out, the question of employers influencing workers’ leisure time is a “really tricky place to go to”.

Another issue is pay. Will tunnelling work become a less desirable if pay is reduced to account for shorter shift lengths? And how is this balanced by safety considerations?

HS2 promoter HS2 Ltd says it has yet to decide what approach it is going to take for its tunnelling work, but shorter working shifts are not currently included in its works information for prospective tenderers.

With a lack of research into the finer details and implications of shorter shifts, the jury is still out on how and in what circumstances they should be implemented. But there is hope says Brown.

“I think in the civil engineering sector, over the last four or five years there’s been a much better understanding of why health and fatigue are important,” he says.

“And there’s a much greater desire to do something about it.”




Readers' comments (1)

  • On the Channel Tunnel, UK side, all the TBM's were on 8 hours change at the face, with most of the rest of the underground work on 10hours change at the surface.

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