Hi All
We were recently contacted by a major UK chain of restaurants to look into whether or not they had a leak between their mains incoming water supply and the main feed at the end of the road.
They had 1 meter provided by the utility company at the end of the road (down a wet 1m deep hole) and some more meters internal in their building connected to the main incoming feed. In theory, the meters internally will match up with the meter at the end of the road.
[fast forward 3 months.]
During the 3 months we have:
- Fitted an eight channel pulse counter to the incoming meters (BBSP-PM8)
- Fitted a battery powered GPRS pulse counting meter to the utility provided meter at the end of the road
- Checked the validity of data from both devices by measuring pulses taken during a week long period and comparing those pulses with the meter readings
- Configured Energy Manager Online with the appropriate data feed points
The graph of the data usage is shown below. The units on the graph are litres used per hour.
You can see clearly that the water meter from the utility has a [reasonably] constant 100 litres per hour feed *more* than the internal water meters are getting which means either:
- We’ve missed something and there is another pipe fitted off of the pipe that runs between the utility meter and the site, or
- There is a leak of around 100 l per hour.
We checked the pipe schematics and there is no other pipe which means there must be a leak.
We did some experiments in the office and found that a gently dribbling tap gave a flow of roughly 1.2 litres in 1 minute which is roughly 100 litres per hour. This will be the sort of magnitude of leak we have discovered. If water costs c. £2 per cubic meter this means that by fixing this leak we save 876 cubic meters of water per year or c. £1,750 per year. Over the 20 year operational life of the building this means the landlords will save c. £35k in total.
We’re pleased to have tracked this down and happy to work with anyone else in a similar situation.