TWO breaks a day in construction gives better cost and schedule performance than one!
At Mafic, using our FairPay technology, a wearable device which attaches to a hardhat and can understand the time-on-tools from the movement of their head, we setup an A/B test with a drylining client completing a prestigious project in London. We ran 2 different shift patterns for a number of weeks. The first was a single 30 minute break at midday, this is represented by the grey line in the figure below. We then took the same group of guys and gave them 2 x 30 minutes break at 10:00 and at 14:00. The results were fascinating. We identified a couple of really interesting mechanisms which can dramatically improve cost and schedule performance and perhaps even quality.
Firstly, in the single break pattern the guys were taking 2 unofficial breaks in the morning around 10:00 and also in the afternoon at 14:30. You can see this in the slight dip in productive minutes on the grey line. This is understandable since it’s very difficult for anyone to work for such a long period of time without a breather. The second really interesting mechanism was the reduction in active time after 15:00. The single break pattern who only had a break at lunchtime, significantly reduced their output in the afternoon compared to the group who had most recently had a break.
The 2-break pattern had a 6-7% labour cost saving over the single break. It could be argued that this saving comes from the fact that the working time in the double shift is 30 minutes shorter, hence the cost is lower. This is true however the active minutes and the number of times a tool was used in the double shift was slightly higher compared to the single shift, meaning the teams are doing more work and installing more screws in 9.0 hours compared with 9.5 hours. Cost Performance AND Schedule Performance both genuinely increase if you move to a double shift.
There are further questions on these tests which we are currently answering such as what about fixed plant costs on site which are charged on a daily basis? To minimise the total cost of these daily hires you need to complete as much work as possible every day. Considering the fatigue curve of the workforce, what is the optimum shift length which will maximise CPI (Cost Performance Index) but will minimise preliminary costs? I’ll give you a hint, it’s not 12 hour shifts (unless you have the worlds most expensive MEWP hire).
There are also more questions about further optimising the shift pattern, morning sessions are most productive and it’s the last afternoon session which needs to ‘protected’ as much as possible. Making the morning breaks as late as possible so the afternoon sessions are as short as possible will likely push productivity by another 2-3%.
In this blog we have identified opportunities for contractors to cut their labour cost by 6-8%. Considering labour is approximately 30-40% of contractor’s overheads and also recognising the number of contractors which are filing for administration every month, these changes represent a 2-3% improvement in profit margins. Not something to be sniffed at! If you are on a single shift I highly recommend you adjust to a double shift. If you want to learn more and improve your operations further then get in touch and I am sure we can help you unlock that hidden profit margin.