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FROM THE FIELD: M&V — How To Do It Right


Lyn Gomes, PE, CCP, LEED AP, CLCATT
kW Engineering

I did a post-occupancy site visit for a job where the M&V component wasn’t designed very well. Our design review comments were not included and it wasn’t coordinated between disciplines. As a result, the problems never got fixed and still plague the project – over a year later. (another lesson learned: unresolved problems in design never go away; the responsibility for fixing them just gets passed along.)

Here are tips for making sure M&V is done right on your next job:

Make sure MEP drawings show all the metering points

  • The ones that were missed ended up being change orders (over $10k worth!)

Create a network diagram

  • This is a must where there are multiple control systems. The diagram was needed to describe the integration scope between the electrical and HVAC systems.

Specify integration

  • This never was done for the electrical meters. As a result, the electrical metering system is standalone and is gathering dust in the electrical room. The data must be manually downloaded, so you know that’s never going to get done

Identify outputs and protocols

  • The electrical metering system spoke Modbus and was on its own platform. HVAC spoke BACnet and was on its own network. Identifying this beforehand would have clued the engineers that they needed scope and equipment to have the two systems work together. To fix would be another $10k change order.
  • Similar issue with the water meters. Most water meters use a pulse protocol (read more about it here). The meter for this project had a digital protocol.

Include communication wiring and any other equipment/gateways/ repeaters/etc. that need to be installed (see above)

Provide details for how the instruments will be installed.

  • The water meters were installed 6’ below grade in a single-width meter box (1’ x 1.5’ x 6’ deep). It was not possible to modify them, much less read them.
  • dP sensors were installed 6’ AFF, making reading the instrument impossible without a ladder.

Don’t ignore metering:

  • Ask about it at bidding
  • Include it in design review (and don’t forget the M&V plan)
  • Make it a part of your controls integration meeting

The instrument and inputs to the BMS must be functionally tested if the Owner hopes to make use of the data. Forewarned is forearmed!

 

 

  1. Ben Burgoyne
    Reply

    Thanks for sharing. In my experience, metering often seems to be one the last after-thoughts – and the topic is a prime example of significant money that can be saved easily by addressing in the design stage. Thinking with the end in mind, I find it helpful to continually ask the project team “in the end, how is the user going to access this data?”

    • Lyn Gomes (author)
      Reply

      Yes, you’re absolutely right!! Unfortunately, when it is a LEED requirement, that question never gets asked

  2. Timothy Heinrich
    Reply

    The points made are spot on and must be pushed at the Engineer/Construction Team.
    If we hadn’t had a BCxA certified Commissioning Agent through CMTA on our HCPSS NetZero ASHRAE Cat II – 1st Place Technology Award for Wilde Lake MS, the metering would have been missed, as we all focused on Resolving immense BAS Contractor Problems, while our CxA never took his eye off the prize by making sure that the Electrical Contractor provided working Lighting Controls, A Jace to translate the ModBus to BACnet and finally to making sure the Kiosk actually read the correct values within 1% accuracy of our Electricity providers readings.
    Without the Collaboration of CxA, Engineer, Construction Manager, Owner & Contractors (Mechanical brought in another acceptable BAS Vendor who got it done right), we certainly would never achieved a 13.8 EUI, when Design was for 22 EUI.
    It still blows my mind what will be accomplished next by BCxA Commissioning Agents!

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