One of the problems that operators face is trying to meter a line that is located in a street / parking lot / or other vehicle traffic area.

While Packaged Metering Manholes provide all-in-one primary device integration with easy operator access in one structure structure, the problem is then what to do with the flow meter. 

The problem is usually solved in one of two ways: either put the flow meter in the same manhole as the primary device or located the flow meter out of the way of the traffic.

• Flow Meter in the Manhole
  • Putting the flow meter in the metering manhole presents a problem if the installation is classified as a confined space.  If that occurs, then confined space entry protocols would have to be followed (involving multiple operators, a hoist, and gas detection equipment).  The need to enter the device manhole can sometimes be eliminated by configuring the manhole so that fixed distance calibration targets can be used (ultrasonic flow meters) or so that the sensor can be removed without manhole entry (bubbler / pressure transducer flow meters), but if the flow meter is installed in the metering manhole, then the operator is back to square one – having to enter the manhole.
• Flow Meter Mounted Away From Manhole
  • The alternate method, putting the flow meter out of the way of traffic, is great – so long as the meter is not so far away that there is an appreciable lag between when the visual observation of the level is made and when it is checked against (or entered into) the flow meter.  As the distance between the metering manhole and the flow meter increased, the greater the chance is that the level changes making the check / calibration entry wrong.

A third approach- and frankly one that we’d never thought of before - is to put in a second, short manhole right next to the metering manhole. 

The second manhole can house the flow meter and any communications equipment or batteries.  If the meter is installed on a telescoping stand, the operator need never even enter the second manhole, the can simply pull up the meter, verify / correct the level, and then stow the flow meter back in the manhole.

Even if the second manhole had to be entered, there may be no need for it to be rated as a confined space if the two manholes are sealed off from each other.